1Department of Materials Science and Engineering Faculty of Engineering and Industrial Technology Silpakorn UniversityNakhon Pathom 73000 Thailand2National Center of Excellence for Petroleum Petrochemicals and Advanced Materials Chulalongkorn UniversityBangkok 10330 Thailand
Correspondence should be addressed to Achanai Buasri achanai130gmailcom
Received 13 August 2014 Accepted 20 October 2014
Academic Editor Alina Balu
Copyright copy 2015 Achanai Buasri et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Microwave-assisted biodiesel production via transesterification of Jatropha curcas oil with methanol using solid oxide catalystderived from waste shells of oyster and Pyramidellawas studiedThe shells were calcined at 900∘C for 2 h and calcium oxide (CaO)catalyst characterizations were carried out by X-ray diffraction (XRD) X-ray fluorescence (XRF) scanning electron microscope(SEM) and the Brunauer-Emmett-Teller (BET) surface area measurements The effects of reaction variables such as reaction timemicrowave powermethanoloilmolar ratio and catalyst loading on the yield of biodieselwere investigated Reusability ofwaste shellcatalyst was also examinedThe results indicated that the economic and environmentally friendly catalysts derived from oyster andPyramidella shells showed good reusability and had high potential to be used as biodiesel production catalysts under microwave-assisted transesterification of Jatropha curcas oil with methanol
1 Introduction
Many recent research programs based on energy sector arefocused on the development of concepts such as renewableresources sustainable development green energy and eco-friendly process [1] Biodiesel a renewable biodegradablenontoxic carbon neutral and environmentally benign fuelfor diesel engines has been attracting considerable interestall over the world which can significantly reduce globalwarming and the dependence on conventional fossil fuels[2] It can be easily synthesized through transesterificationof oil or esterification of fats using basic acidic enzymaticor other kinds of catalysts with heating functions [3 4]Most commonly biodiesel production utilizes an alkalinecatalyst but it is difficult to adapt this process for use withsome waste oils and fats [5] Moreover in this conventionalhomogeneous method the removal of catalysts after reactionis technically difficult and a large amount of waste-water is
produced to separate the catalyst and clean the productsTherefore heterogeneous catalysts are very important forbiodiesel synthesis as these catalysts have many advantagesover homogeneous catalysts [6]
Calcium oxide (CaO) is one of the most promisingheterogeneous alkali catalysts since it is cheap and abundantlyavailable in nature and some of the sources of this compoundare renewable [7] It closely resembled an environmentallyfriendly material Generally calcium carbonate (CaCO
3) is
the raw material to produce CaO Besides the economicadvantage the performance of CaO as catalyst for biodieselproduction is also comparable to several homogeneous cat-alysts [8] There are several natural calcium sources fromwastes such as eggshell crab shell and animal bone Usingwastes as raw materials for catalyst synthesis could eliminatethe wastes and simultaneously produced the catalysts withhigh cost effectiveness [9] The catalyst synthesized withthe waste shells opens door for renewable catalyst and at
Hindawi Publishing CorporationJournal of ChemistryVolume 2015 Article ID 578625 7 pageshttpdxdoiorg1011552015578625
2 Journal of Chemistry
CalcinedCrushed
Oyster shell
Pyramidella shell
Sieved
Figure 1 Preparation of CaO catalyst derived from oyster and Pyramidella shells
the same time recycles the waste generated These shellsmay also find their utility in other base catalyzed importantorganic reactions which will add value to the waste generated[1 4] Oyster and Pyramidella are found in several parts ofThailand In the production of oyster and Pyramidella prod-ucts on very large scale the processing also produces signif-icant amounts of shell waste The aim of this investigation isto examine the effect of the microwave irradiation generatedfrom a household microwave for the transesterification ofJatropha curcas (physic nut) oil with methanol into biodieselwhen a solid CaO catalyst derived from waste oyster andPyramidella shells was employedThe effects of reaction timemicrowave power methanoloil molar ratio catalyst loadingand reusability of catalyst were systematically investigated
2 Materials and Methods
21 Materials Jatropha curcas oil was purchased from ThaiPhysic Nut Oil Company Limited Thailand The oyster andPyramidella shells were collected as wastes from universitycafeterias and bay in southernThailandThewaste shells wererinsed with water to remove dust and impurities and werethen dried in an oven at 80∘C for 12 h All chemicals wereanalytical-grade reagents (Merck gt99 purity) and wereused as received
22 Preparation of CaO Catalysts Thedried oyster and Pyra-midella shells were crushed and sieved to pass 100ndash200meshscreens (38ndash75 120583m) The solid catalysts were prepared by acalcination method The waste shells were calcined at 900∘Cin air atmosphere with a heating rate of 10∘Cmin for 2 h [3]The products (CaO catalyst) were obtained as white powderAll calcined samples were kept in the close vessel to avoidthe reaction with carbon dioxide (CO
2) and humidity in air
before used [4] Figure 1 showed the preparation process ofwaste shell-derived catalyst
23 Characterization of CaO Catalysts A Rigaku (MiniFlexII England) X-ray diffraction (XRD) analyzer was usedto examine the catalysts Samples were ground at room
temperature in an alumina mortar and pestle and placed onthe XRD holder Samples were analyzed at 40 kV and 44mAat an angle of diffraction (2120579) between 15∘ and 80∘ with a step-size of 004∘ and a scan rate of 3∘min
The inorganic compositions of the catalysts were deter-mined by an X-ray fluorescence spectroscopy (XRF OxfordED-2000 England) under energy dispersivemode for precisemeasurement of both light and heavy elements
The microstructures of the calcined waste shells wereobserved by a scanning electron microscope (SEM) TheSEM images of the representative sample were obtained froma Camscan-MX 2000 (England) equipped with an energydispersive spectroscope (EDS)
The surface area mean pore diameter and pore volumeof the catalysts were determined using a QuantachromeInstrument (Autosorb-1 Model No ASIMPVP4 USA) basedon the nitrogen (N
2) adsorption-desorption method at 77K
Prior to the analysis all samples were degassed at 300∘C for4 h to desorb the volatiles (if any) from the surface A residualpressure of 300 120583mHg for 24 hwas performedusing the degasport The surface area was calculated using the Brunauer-Emmett-Teller (BET) equation and the mean pore diameterand pore volume were obtained by applying the Barrett-Joyner-Halenda (BJH)method on the desorption branch [10]
24 Transesterification of Jatropha curcas Oil with MethanolThe reactions were carried out in a 500mL glass reactorequipped with condenser and mechanical stirrer at atmo-spheric pressure placed inside a household microwave oven(Samsung Korea) The fixed 100 g of Jatropha curcas oil andthe desired amount of the derived CaO catalysts (2 3 4 5and 6wt) were added to the reactor and then the methanolwas introduced to the oil at variousmethanoloil molar ratiosof 9 1 12 1 15 1 18 1 and 21 1 The transesterification wasoperated at 180ndash800W with varied reaction time of 2ndash6minunder microwave irradiation (Figure 2) and it was instantlystopped by rapid cooling in an ice bath In some cases thereaction was allowed to proceed for a period of time after themicrowave irradiation was stopped [3] All experiments were
Journal of Chemistry 3
Figure 2 Microwave reactor for biodiesel production
repeated 3 times and the standard deviation was never higherthan 7 for any point
Composition of the fatty acid methyl ester (FAME) wasanalyzed with gas chromatograph-mass spectrometry (GC-MS QP2010 Plus Shimadzu Corporation Japan) equippedwith a flame ionization detector (FID) and a capillary column30m times 032mm times 025 120583m (DB-WAX Carbowax 20M) Yieldof FAME was calculated by
Yield () =119898119894119860119887
119860119894119898119887
times 100 (1)
where 119898119894is the mass of internal standard added to the
sample 119860119894is the peak area of internal standard 119898
119887is the
mass of the biodiesel sample and 119860119887is the peak area of the
biodiesel sample [11] The physical and chemical propertiesof FAME including kinematic viscosity density flash pointcloud point pour point acid value and water content wereanalyzed according to ASTMmethods [12]
3 Results and Discussions
The major component of both oyster and Pyramidella shellswas CaCO
3with the absence of CaO peak as demonstrated
by their clear XRD patterns Figures 3 and 4 show thechanges in the XRD pattern of the waste shells with thecalcination method The waste shells maintained their XRDpatterns of CaCO
3 while materials calcined at 900∘C for
2 h exhibited those of CaO indicating that the completeconversion of CaCO
3to CaO by evolving the carbon dioxide
(CO2) required the calcination above 800∘C [13] Narrow and
high intense peaks of the calcined catalyst define the well-crystallized structure of the CaO catalyst [7 14] The resultreveals sharp XRD reflections with (1 1 1) (2 0 0) (2 2 0) (3 11) and (2 2 2) orientations implying that the calcinedmaterialwas well crystallized during the heat treatment process [4]
The major element present in the catalyst is calcium(94wt) in the form of oxide and is the active material
0 10 20 30 40 50 60 70 80 90
Inte
nsity
(au
)
Natural shell
Calcined shell
2-120579
Figure 3 XRD patterns of natural and calcined oyster shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
0 10 20 30 40 50 60 70 80 90In
tens
ity (a
u)
2-120579
Natural shell
Calcined shell
Figure 4 XRD patterns of natural and calcined Pyramidella shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
Table 1 Chemical compositions of waste shell-derived catalyst
for the conversion of triglyceride (TG) into methyl ester(ME) Si Mg Al Sr Na Fe Te and so forth were foundin trace amounts (Table 1) The presence of calcium as themajor constituent was an indication that the waste shellcomprised ofCaCO
3and upon calcination they can be almost
completely converted to CaO [15]The microscopic features of oyster and Pyramidella shells
calcined at 900∘C (2 h) were examined by high resolutionSEM (Figure 5) The natural waste shell displays a typicallayered architecture [16] With the calcination temperatureat 900∘C the microstructures of natural shell are changedsignificantly from layered architecture to porous structure[17] The calcined oyster shell showed similar particle mor-phology with the calcined Pyramidella shell The calcined
4 Journal of Chemistry
(a) (b)
(c) (d)
Figure 5 SEM images of (a) natural oyster shell (b) calcined oyster shell (c) natural Pyramidella shell and (d) calcined Pyramidella shell
Table 2 The physical properties of waste shell-derived catalyst
waste shells were irregular in shape and some of thembonded together as aggregates However the smaller sizeof the grains and aggregates could provide higher specificsurface areas Since all samples are considered to be less-porous or even nonporous the size of the particle shoulddirectly respond to the surface area [18]
The physical properties (surface area mean pore diam-eter and pore volume) of the catalyst are summarized inTable 2 The calcined oyster shell had the surface area24m2g pore diameter 66 A and pore volume (004 cm3g)and presented a uniform pore size The calcined Pyramidellashell present higher values for surface area (29m2g) andpore volume (006 cm3g) related to oyster shellThe calcinedsample was well crystallized during the heat treatment pro-cess Furthermore the chemical composition of the calcinedcatalyst mainly contains a high purity of CaO with a largebasic strength and a variety of basic sites The basicityon the catalyst surface is of key importance in biodiesel
production [3] It can be seen that the heterogeneous catalystresulted in a strong increase in the active sites [19]
The effect of single variable on the biodiesel yield suchas reaction time microwave power methanoloil molar ratiocatalyst loading and reusability of catalyst was examined(Figures 6ndash10) For the following experiments calcined oysterand Pyramidella shell were used as low-cost catalyst to cat-alyze the microwave-assisted transesterification of Jatrophacurcas oil and methanol
Figure 6 depicts the reaction time dependence of FAMEyield during transesterification by employing oyster andPyramidella shells derived catalyst It shows an increasein the yield with time from 2 to 5min with a catalystamount of 4wt relative to oil and a methanoloil molarratio of 15 1 The maximum yields of 9481 and 9512were obtained in 6min at 800W for oyster and Pyramidellashell respectively In the initial stages of the microwave-assisted transesterification reaction production of biodieselwas rapid and the rate diminished and finally reachedequilibrium [20] in about 5minThis can be explained by thefact that transesterification reaction between Jatropha curcasoil and methanol is reversible when the reaction time is longenough [21]
In order to determine the optimum parametric con-ditions for production of biodiesel assisted by microwaveirradiation the effect of power supplied by the microwaveoven was studied The FAME result shown in Figure 7elucidated the effect of microwave power at 150W (2658)
Journal of Chemistry 5
60
65
70
75
80
85
90
95
100
2 3 4 5 6
Yiel
d of
FA
ME
Reaction time (min)
Oyster shellPyramidella shell
Figure 6 Effect of reaction time on yield of FAME
Oyster shellPyramidella shell
20
40
60
80
100
150 300 450 600 800
Yiel
d of
FA
ME
Microwave power (W)
Figure 7 Effect of microwave power on yield of FAME
Oyster shellPyramidella shell
60
70
80
90
100
9 12 15 18 21
Yield
of F
AM
E
Methanoloil molar ratio (mdash)
Figure 8 Effect of methanoloil molar ratio on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
0 2 3 4 5 6
Yiel
d of
FA
ME
Catalyst loading (wt)
Figure 9 Effect of catalyst loading on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
1 2 3
Yiel
d of
FA
ME
Number of catalyst reusability
Figure 10 Effect of reusability of catalyst on yield of FAME
300W (4584) 450W (5737) 600W (7590) and800W (9392) for oyster shell It was clear that highermicrowave power gave rise to higher biodiesel yield Thusthe microwave power of 800W would be chosen for fur-ther investigationThemicrowave-assisted transesterificationreaction overwaste shell-derived catalysts could proceedwitha rapid reaction time It was considered that the related chem-ical reactions are accelerated by microwave energy givingrise to intense localized heating and thereby accelerating thechemical reaction and giving high product yields in a shorttime [3]
The effect of increasing the methanoloil molar ratio wasalso studied with the 4wt CaO catalysts Figure 8 shows theFAME conversion over time using molar ratios of methanolto oil of 9 1 12 1 15 1 18 1 and 21 1The lowermethanoloilratios resulted in poor suspension of the slurry in the reactingsolution which possibly induced mass transfer problemsthus resulting in lower activity On the other hand andin accordance with reported literature the activity steadily
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
Figure 1 Preparation of CaO catalyst derived from oyster and Pyramidella shells
the same time recycles the waste generated These shellsmay also find their utility in other base catalyzed importantorganic reactions which will add value to the waste generated[1 4] Oyster and Pyramidella are found in several parts ofThailand In the production of oyster and Pyramidella prod-ucts on very large scale the processing also produces signif-icant amounts of shell waste The aim of this investigation isto examine the effect of the microwave irradiation generatedfrom a household microwave for the transesterification ofJatropha curcas (physic nut) oil with methanol into biodieselwhen a solid CaO catalyst derived from waste oyster andPyramidella shells was employedThe effects of reaction timemicrowave power methanoloil molar ratio catalyst loadingand reusability of catalyst were systematically investigated
2 Materials and Methods
21 Materials Jatropha curcas oil was purchased from ThaiPhysic Nut Oil Company Limited Thailand The oyster andPyramidella shells were collected as wastes from universitycafeterias and bay in southernThailandThewaste shells wererinsed with water to remove dust and impurities and werethen dried in an oven at 80∘C for 12 h All chemicals wereanalytical-grade reagents (Merck gt99 purity) and wereused as received
22 Preparation of CaO Catalysts Thedried oyster and Pyra-midella shells were crushed and sieved to pass 100ndash200meshscreens (38ndash75 120583m) The solid catalysts were prepared by acalcination method The waste shells were calcined at 900∘Cin air atmosphere with a heating rate of 10∘Cmin for 2 h [3]The products (CaO catalyst) were obtained as white powderAll calcined samples were kept in the close vessel to avoidthe reaction with carbon dioxide (CO
2) and humidity in air
before used [4] Figure 1 showed the preparation process ofwaste shell-derived catalyst
23 Characterization of CaO Catalysts A Rigaku (MiniFlexII England) X-ray diffraction (XRD) analyzer was usedto examine the catalysts Samples were ground at room
temperature in an alumina mortar and pestle and placed onthe XRD holder Samples were analyzed at 40 kV and 44mAat an angle of diffraction (2120579) between 15∘ and 80∘ with a step-size of 004∘ and a scan rate of 3∘min
The inorganic compositions of the catalysts were deter-mined by an X-ray fluorescence spectroscopy (XRF OxfordED-2000 England) under energy dispersivemode for precisemeasurement of both light and heavy elements
The microstructures of the calcined waste shells wereobserved by a scanning electron microscope (SEM) TheSEM images of the representative sample were obtained froma Camscan-MX 2000 (England) equipped with an energydispersive spectroscope (EDS)
The surface area mean pore diameter and pore volumeof the catalysts were determined using a QuantachromeInstrument (Autosorb-1 Model No ASIMPVP4 USA) basedon the nitrogen (N
2) adsorption-desorption method at 77K
Prior to the analysis all samples were degassed at 300∘C for4 h to desorb the volatiles (if any) from the surface A residualpressure of 300 120583mHg for 24 hwas performedusing the degasport The surface area was calculated using the Brunauer-Emmett-Teller (BET) equation and the mean pore diameterand pore volume were obtained by applying the Barrett-Joyner-Halenda (BJH)method on the desorption branch [10]
24 Transesterification of Jatropha curcas Oil with MethanolThe reactions were carried out in a 500mL glass reactorequipped with condenser and mechanical stirrer at atmo-spheric pressure placed inside a household microwave oven(Samsung Korea) The fixed 100 g of Jatropha curcas oil andthe desired amount of the derived CaO catalysts (2 3 4 5and 6wt) were added to the reactor and then the methanolwas introduced to the oil at variousmethanoloil molar ratiosof 9 1 12 1 15 1 18 1 and 21 1 The transesterification wasoperated at 180ndash800W with varied reaction time of 2ndash6minunder microwave irradiation (Figure 2) and it was instantlystopped by rapid cooling in an ice bath In some cases thereaction was allowed to proceed for a period of time after themicrowave irradiation was stopped [3] All experiments were
Journal of Chemistry 3
Figure 2 Microwave reactor for biodiesel production
repeated 3 times and the standard deviation was never higherthan 7 for any point
Composition of the fatty acid methyl ester (FAME) wasanalyzed with gas chromatograph-mass spectrometry (GC-MS QP2010 Plus Shimadzu Corporation Japan) equippedwith a flame ionization detector (FID) and a capillary column30m times 032mm times 025 120583m (DB-WAX Carbowax 20M) Yieldof FAME was calculated by
Yield () =119898119894119860119887
119860119894119898119887
times 100 (1)
where 119898119894is the mass of internal standard added to the
sample 119860119894is the peak area of internal standard 119898
119887is the
mass of the biodiesel sample and 119860119887is the peak area of the
biodiesel sample [11] The physical and chemical propertiesof FAME including kinematic viscosity density flash pointcloud point pour point acid value and water content wereanalyzed according to ASTMmethods [12]
3 Results and Discussions
The major component of both oyster and Pyramidella shellswas CaCO
3with the absence of CaO peak as demonstrated
by their clear XRD patterns Figures 3 and 4 show thechanges in the XRD pattern of the waste shells with thecalcination method The waste shells maintained their XRDpatterns of CaCO
3 while materials calcined at 900∘C for
2 h exhibited those of CaO indicating that the completeconversion of CaCO
3to CaO by evolving the carbon dioxide
(CO2) required the calcination above 800∘C [13] Narrow and
high intense peaks of the calcined catalyst define the well-crystallized structure of the CaO catalyst [7 14] The resultreveals sharp XRD reflections with (1 1 1) (2 0 0) (2 2 0) (3 11) and (2 2 2) orientations implying that the calcinedmaterialwas well crystallized during the heat treatment process [4]
The major element present in the catalyst is calcium(94wt) in the form of oxide and is the active material
0 10 20 30 40 50 60 70 80 90
Inte
nsity
(au
)
Natural shell
Calcined shell
2-120579
Figure 3 XRD patterns of natural and calcined oyster shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
0 10 20 30 40 50 60 70 80 90In
tens
ity (a
u)
2-120579
Natural shell
Calcined shell
Figure 4 XRD patterns of natural and calcined Pyramidella shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
Table 1 Chemical compositions of waste shell-derived catalyst
for the conversion of triglyceride (TG) into methyl ester(ME) Si Mg Al Sr Na Fe Te and so forth were foundin trace amounts (Table 1) The presence of calcium as themajor constituent was an indication that the waste shellcomprised ofCaCO
3and upon calcination they can be almost
completely converted to CaO [15]The microscopic features of oyster and Pyramidella shells
calcined at 900∘C (2 h) were examined by high resolutionSEM (Figure 5) The natural waste shell displays a typicallayered architecture [16] With the calcination temperatureat 900∘C the microstructures of natural shell are changedsignificantly from layered architecture to porous structure[17] The calcined oyster shell showed similar particle mor-phology with the calcined Pyramidella shell The calcined
4 Journal of Chemistry
(a) (b)
(c) (d)
Figure 5 SEM images of (a) natural oyster shell (b) calcined oyster shell (c) natural Pyramidella shell and (d) calcined Pyramidella shell
Table 2 The physical properties of waste shell-derived catalyst
waste shells were irregular in shape and some of thembonded together as aggregates However the smaller sizeof the grains and aggregates could provide higher specificsurface areas Since all samples are considered to be less-porous or even nonporous the size of the particle shoulddirectly respond to the surface area [18]
The physical properties (surface area mean pore diam-eter and pore volume) of the catalyst are summarized inTable 2 The calcined oyster shell had the surface area24m2g pore diameter 66 A and pore volume (004 cm3g)and presented a uniform pore size The calcined Pyramidellashell present higher values for surface area (29m2g) andpore volume (006 cm3g) related to oyster shellThe calcinedsample was well crystallized during the heat treatment pro-cess Furthermore the chemical composition of the calcinedcatalyst mainly contains a high purity of CaO with a largebasic strength and a variety of basic sites The basicityon the catalyst surface is of key importance in biodiesel
production [3] It can be seen that the heterogeneous catalystresulted in a strong increase in the active sites [19]
The effect of single variable on the biodiesel yield suchas reaction time microwave power methanoloil molar ratiocatalyst loading and reusability of catalyst was examined(Figures 6ndash10) For the following experiments calcined oysterand Pyramidella shell were used as low-cost catalyst to cat-alyze the microwave-assisted transesterification of Jatrophacurcas oil and methanol
Figure 6 depicts the reaction time dependence of FAMEyield during transesterification by employing oyster andPyramidella shells derived catalyst It shows an increasein the yield with time from 2 to 5min with a catalystamount of 4wt relative to oil and a methanoloil molarratio of 15 1 The maximum yields of 9481 and 9512were obtained in 6min at 800W for oyster and Pyramidellashell respectively In the initial stages of the microwave-assisted transesterification reaction production of biodieselwas rapid and the rate diminished and finally reachedequilibrium [20] in about 5minThis can be explained by thefact that transesterification reaction between Jatropha curcasoil and methanol is reversible when the reaction time is longenough [21]
In order to determine the optimum parametric con-ditions for production of biodiesel assisted by microwaveirradiation the effect of power supplied by the microwaveoven was studied The FAME result shown in Figure 7elucidated the effect of microwave power at 150W (2658)
Journal of Chemistry 5
60
65
70
75
80
85
90
95
100
2 3 4 5 6
Yiel
d of
FA
ME
Reaction time (min)
Oyster shellPyramidella shell
Figure 6 Effect of reaction time on yield of FAME
Oyster shellPyramidella shell
20
40
60
80
100
150 300 450 600 800
Yiel
d of
FA
ME
Microwave power (W)
Figure 7 Effect of microwave power on yield of FAME
Oyster shellPyramidella shell
60
70
80
90
100
9 12 15 18 21
Yield
of F
AM
E
Methanoloil molar ratio (mdash)
Figure 8 Effect of methanoloil molar ratio on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
0 2 3 4 5 6
Yiel
d of
FA
ME
Catalyst loading (wt)
Figure 9 Effect of catalyst loading on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
1 2 3
Yiel
d of
FA
ME
Number of catalyst reusability
Figure 10 Effect of reusability of catalyst on yield of FAME
300W (4584) 450W (5737) 600W (7590) and800W (9392) for oyster shell It was clear that highermicrowave power gave rise to higher biodiesel yield Thusthe microwave power of 800W would be chosen for fur-ther investigationThemicrowave-assisted transesterificationreaction overwaste shell-derived catalysts could proceedwitha rapid reaction time It was considered that the related chem-ical reactions are accelerated by microwave energy givingrise to intense localized heating and thereby accelerating thechemical reaction and giving high product yields in a shorttime [3]
The effect of increasing the methanoloil molar ratio wasalso studied with the 4wt CaO catalysts Figure 8 shows theFAME conversion over time using molar ratios of methanolto oil of 9 1 12 1 15 1 18 1 and 21 1The lowermethanoloilratios resulted in poor suspension of the slurry in the reactingsolution which possibly induced mass transfer problemsthus resulting in lower activity On the other hand andin accordance with reported literature the activity steadily
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
Figure 2 Microwave reactor for biodiesel production
repeated 3 times and the standard deviation was never higherthan 7 for any point
Composition of the fatty acid methyl ester (FAME) wasanalyzed with gas chromatograph-mass spectrometry (GC-MS QP2010 Plus Shimadzu Corporation Japan) equippedwith a flame ionization detector (FID) and a capillary column30m times 032mm times 025 120583m (DB-WAX Carbowax 20M) Yieldof FAME was calculated by
Yield () =119898119894119860119887
119860119894119898119887
times 100 (1)
where 119898119894is the mass of internal standard added to the
sample 119860119894is the peak area of internal standard 119898
119887is the
mass of the biodiesel sample and 119860119887is the peak area of the
biodiesel sample [11] The physical and chemical propertiesof FAME including kinematic viscosity density flash pointcloud point pour point acid value and water content wereanalyzed according to ASTMmethods [12]
3 Results and Discussions
The major component of both oyster and Pyramidella shellswas CaCO
3with the absence of CaO peak as demonstrated
by their clear XRD patterns Figures 3 and 4 show thechanges in the XRD pattern of the waste shells with thecalcination method The waste shells maintained their XRDpatterns of CaCO
3 while materials calcined at 900∘C for
2 h exhibited those of CaO indicating that the completeconversion of CaCO
3to CaO by evolving the carbon dioxide
(CO2) required the calcination above 800∘C [13] Narrow and
high intense peaks of the calcined catalyst define the well-crystallized structure of the CaO catalyst [7 14] The resultreveals sharp XRD reflections with (1 1 1) (2 0 0) (2 2 0) (3 11) and (2 2 2) orientations implying that the calcinedmaterialwas well crystallized during the heat treatment process [4]
The major element present in the catalyst is calcium(94wt) in the form of oxide and is the active material
0 10 20 30 40 50 60 70 80 90
Inte
nsity
(au
)
Natural shell
Calcined shell
2-120579
Figure 3 XRD patterns of natural and calcined oyster shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
0 10 20 30 40 50 60 70 80 90In
tens
ity (a
u)
2-120579
Natural shell
Calcined shell
Figure 4 XRD patterns of natural and calcined Pyramidella shell(symbols e CaCO
3
998771CaO andX Ca(OH)2
)
Table 1 Chemical compositions of waste shell-derived catalyst
for the conversion of triglyceride (TG) into methyl ester(ME) Si Mg Al Sr Na Fe Te and so forth were foundin trace amounts (Table 1) The presence of calcium as themajor constituent was an indication that the waste shellcomprised ofCaCO
3and upon calcination they can be almost
completely converted to CaO [15]The microscopic features of oyster and Pyramidella shells
calcined at 900∘C (2 h) were examined by high resolutionSEM (Figure 5) The natural waste shell displays a typicallayered architecture [16] With the calcination temperatureat 900∘C the microstructures of natural shell are changedsignificantly from layered architecture to porous structure[17] The calcined oyster shell showed similar particle mor-phology with the calcined Pyramidella shell The calcined
4 Journal of Chemistry
(a) (b)
(c) (d)
Figure 5 SEM images of (a) natural oyster shell (b) calcined oyster shell (c) natural Pyramidella shell and (d) calcined Pyramidella shell
Table 2 The physical properties of waste shell-derived catalyst
waste shells were irregular in shape and some of thembonded together as aggregates However the smaller sizeof the grains and aggregates could provide higher specificsurface areas Since all samples are considered to be less-porous or even nonporous the size of the particle shoulddirectly respond to the surface area [18]
The physical properties (surface area mean pore diam-eter and pore volume) of the catalyst are summarized inTable 2 The calcined oyster shell had the surface area24m2g pore diameter 66 A and pore volume (004 cm3g)and presented a uniform pore size The calcined Pyramidellashell present higher values for surface area (29m2g) andpore volume (006 cm3g) related to oyster shellThe calcinedsample was well crystallized during the heat treatment pro-cess Furthermore the chemical composition of the calcinedcatalyst mainly contains a high purity of CaO with a largebasic strength and a variety of basic sites The basicityon the catalyst surface is of key importance in biodiesel
production [3] It can be seen that the heterogeneous catalystresulted in a strong increase in the active sites [19]
The effect of single variable on the biodiesel yield suchas reaction time microwave power methanoloil molar ratiocatalyst loading and reusability of catalyst was examined(Figures 6ndash10) For the following experiments calcined oysterand Pyramidella shell were used as low-cost catalyst to cat-alyze the microwave-assisted transesterification of Jatrophacurcas oil and methanol
Figure 6 depicts the reaction time dependence of FAMEyield during transesterification by employing oyster andPyramidella shells derived catalyst It shows an increasein the yield with time from 2 to 5min with a catalystamount of 4wt relative to oil and a methanoloil molarratio of 15 1 The maximum yields of 9481 and 9512were obtained in 6min at 800W for oyster and Pyramidellashell respectively In the initial stages of the microwave-assisted transesterification reaction production of biodieselwas rapid and the rate diminished and finally reachedequilibrium [20] in about 5minThis can be explained by thefact that transesterification reaction between Jatropha curcasoil and methanol is reversible when the reaction time is longenough [21]
In order to determine the optimum parametric con-ditions for production of biodiesel assisted by microwaveirradiation the effect of power supplied by the microwaveoven was studied The FAME result shown in Figure 7elucidated the effect of microwave power at 150W (2658)
Journal of Chemistry 5
60
65
70
75
80
85
90
95
100
2 3 4 5 6
Yiel
d of
FA
ME
Reaction time (min)
Oyster shellPyramidella shell
Figure 6 Effect of reaction time on yield of FAME
Oyster shellPyramidella shell
20
40
60
80
100
150 300 450 600 800
Yiel
d of
FA
ME
Microwave power (W)
Figure 7 Effect of microwave power on yield of FAME
Oyster shellPyramidella shell
60
70
80
90
100
9 12 15 18 21
Yield
of F
AM
E
Methanoloil molar ratio (mdash)
Figure 8 Effect of methanoloil molar ratio on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
0 2 3 4 5 6
Yiel
d of
FA
ME
Catalyst loading (wt)
Figure 9 Effect of catalyst loading on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
1 2 3
Yiel
d of
FA
ME
Number of catalyst reusability
Figure 10 Effect of reusability of catalyst on yield of FAME
300W (4584) 450W (5737) 600W (7590) and800W (9392) for oyster shell It was clear that highermicrowave power gave rise to higher biodiesel yield Thusthe microwave power of 800W would be chosen for fur-ther investigationThemicrowave-assisted transesterificationreaction overwaste shell-derived catalysts could proceedwitha rapid reaction time It was considered that the related chem-ical reactions are accelerated by microwave energy givingrise to intense localized heating and thereby accelerating thechemical reaction and giving high product yields in a shorttime [3]
The effect of increasing the methanoloil molar ratio wasalso studied with the 4wt CaO catalysts Figure 8 shows theFAME conversion over time using molar ratios of methanolto oil of 9 1 12 1 15 1 18 1 and 21 1The lowermethanoloilratios resulted in poor suspension of the slurry in the reactingsolution which possibly induced mass transfer problemsthus resulting in lower activity On the other hand andin accordance with reported literature the activity steadily
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
waste shells were irregular in shape and some of thembonded together as aggregates However the smaller sizeof the grains and aggregates could provide higher specificsurface areas Since all samples are considered to be less-porous or even nonporous the size of the particle shoulddirectly respond to the surface area [18]
The physical properties (surface area mean pore diam-eter and pore volume) of the catalyst are summarized inTable 2 The calcined oyster shell had the surface area24m2g pore diameter 66 A and pore volume (004 cm3g)and presented a uniform pore size The calcined Pyramidellashell present higher values for surface area (29m2g) andpore volume (006 cm3g) related to oyster shellThe calcinedsample was well crystallized during the heat treatment pro-cess Furthermore the chemical composition of the calcinedcatalyst mainly contains a high purity of CaO with a largebasic strength and a variety of basic sites The basicityon the catalyst surface is of key importance in biodiesel
production [3] It can be seen that the heterogeneous catalystresulted in a strong increase in the active sites [19]
The effect of single variable on the biodiesel yield suchas reaction time microwave power methanoloil molar ratiocatalyst loading and reusability of catalyst was examined(Figures 6ndash10) For the following experiments calcined oysterand Pyramidella shell were used as low-cost catalyst to cat-alyze the microwave-assisted transesterification of Jatrophacurcas oil and methanol
Figure 6 depicts the reaction time dependence of FAMEyield during transesterification by employing oyster andPyramidella shells derived catalyst It shows an increasein the yield with time from 2 to 5min with a catalystamount of 4wt relative to oil and a methanoloil molarratio of 15 1 The maximum yields of 9481 and 9512were obtained in 6min at 800W for oyster and Pyramidellashell respectively In the initial stages of the microwave-assisted transesterification reaction production of biodieselwas rapid and the rate diminished and finally reachedequilibrium [20] in about 5minThis can be explained by thefact that transesterification reaction between Jatropha curcasoil and methanol is reversible when the reaction time is longenough [21]
In order to determine the optimum parametric con-ditions for production of biodiesel assisted by microwaveirradiation the effect of power supplied by the microwaveoven was studied The FAME result shown in Figure 7elucidated the effect of microwave power at 150W (2658)
Journal of Chemistry 5
60
65
70
75
80
85
90
95
100
2 3 4 5 6
Yiel
d of
FA
ME
Reaction time (min)
Oyster shellPyramidella shell
Figure 6 Effect of reaction time on yield of FAME
Oyster shellPyramidella shell
20
40
60
80
100
150 300 450 600 800
Yiel
d of
FA
ME
Microwave power (W)
Figure 7 Effect of microwave power on yield of FAME
Oyster shellPyramidella shell
60
70
80
90
100
9 12 15 18 21
Yield
of F
AM
E
Methanoloil molar ratio (mdash)
Figure 8 Effect of methanoloil molar ratio on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
0 2 3 4 5 6
Yiel
d of
FA
ME
Catalyst loading (wt)
Figure 9 Effect of catalyst loading on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
1 2 3
Yiel
d of
FA
ME
Number of catalyst reusability
Figure 10 Effect of reusability of catalyst on yield of FAME
300W (4584) 450W (5737) 600W (7590) and800W (9392) for oyster shell It was clear that highermicrowave power gave rise to higher biodiesel yield Thusthe microwave power of 800W would be chosen for fur-ther investigationThemicrowave-assisted transesterificationreaction overwaste shell-derived catalysts could proceedwitha rapid reaction time It was considered that the related chem-ical reactions are accelerated by microwave energy givingrise to intense localized heating and thereby accelerating thechemical reaction and giving high product yields in a shorttime [3]
The effect of increasing the methanoloil molar ratio wasalso studied with the 4wt CaO catalysts Figure 8 shows theFAME conversion over time using molar ratios of methanolto oil of 9 1 12 1 15 1 18 1 and 21 1The lowermethanoloilratios resulted in poor suspension of the slurry in the reactingsolution which possibly induced mass transfer problemsthus resulting in lower activity On the other hand andin accordance with reported literature the activity steadily
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
Figure 7 Effect of microwave power on yield of FAME
Oyster shellPyramidella shell
60
70
80
90
100
9 12 15 18 21
Yield
of F
AM
E
Methanoloil molar ratio (mdash)
Figure 8 Effect of methanoloil molar ratio on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
0 2 3 4 5 6
Yiel
d of
FA
ME
Catalyst loading (wt)
Figure 9 Effect of catalyst loading on yield of FAME
Oyster shellPyramidella shell
0
20
40
60
80
100
1 2 3
Yiel
d of
FA
ME
Number of catalyst reusability
Figure 10 Effect of reusability of catalyst on yield of FAME
300W (4584) 450W (5737) 600W (7590) and800W (9392) for oyster shell It was clear that highermicrowave power gave rise to higher biodiesel yield Thusthe microwave power of 800W would be chosen for fur-ther investigationThemicrowave-assisted transesterificationreaction overwaste shell-derived catalysts could proceedwitha rapid reaction time It was considered that the related chem-ical reactions are accelerated by microwave energy givingrise to intense localized heating and thereby accelerating thechemical reaction and giving high product yields in a shorttime [3]
The effect of increasing the methanoloil molar ratio wasalso studied with the 4wt CaO catalysts Figure 8 shows theFAME conversion over time using molar ratios of methanolto oil of 9 1 12 1 15 1 18 1 and 21 1The lowermethanoloilratios resulted in poor suspension of the slurry in the reactingsolution which possibly induced mass transfer problemsthus resulting in lower activity On the other hand andin accordance with reported literature the activity steadily
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
Kinematic viscosity (mm2s) 45 44 10ndash60 35ndash50Density (gcm3) 0879 0876 NS 0860ndash0900Flash point (∘C) 163 162 130 Min 120 MinCloud point (∘C) 11 13 NS NSPour point (∘C) 8 9 NS NSAcid value (mgKOHg oil) 037 041 08 Max 05 MaxWater content () 001 002 0050 Max 0050 MaxNS not specified Min minimum and Max maximum
increased with higher methanoloil molar ratios [22] TheFAME content increased significantly when the methanoloilmolar ratio was changed from 9 to 21 The high amount ofmethanol promoted the formation of methoxy species onthe CaO surface leading to a shift in the equilibrium inthe forward direction thus increasing the rate of conversionup to 9392 and 9481 for oyster and Pyramidella shellrespectively However further increases in the methanoloilmolar ratio did not promote the reaction It is understoodthat the glycerol would largely dissolve in excessive methanoland subsequently inhibit the reaction of methanol to thereactants and catalyst thus interfering with the separation ofglycerin which in turn lowers the conversion by shifting theequilibrium in the reverse direction [4 23]
The effect of catalyst amount on the Jatropha curcas oilconversion has been evaluated by running the microwave-assisted transesterification at 800W for 5min with catalystsubsequently 2 3 4 5 and 6wt with respect to the amountof oil loaded in the reactor In the absence of catalystthere was no FAME formed in the reaction A maximumconversion of 9481was obtainedwith a CaO catalyst (Pyra-midella shell) loading of 4wt The lower yields at catalystconcentrations above 4wt were due to the formation ofslurries which were too viscous for adequate mixing Thisresult implies that the transesterification of TG is stronglydependent on the amount of basic sites [24] From this studywe can conclude that the suitable amount of CaO required forthe transesterification of Jatropha curcas oil with methanol is4 wt
The reusability of the CaO catalyst prepared at the opti-mumpreparation conditionswas investigated by carrying outsubsequent reaction cycles After 5min of the reaction thecatalyst was separated from the reaction mixture by filtrationfollowed by washing with methanol to remove any adsorbedstains Afterwards it was dried at 80∘C in an oven for 12 hand was used again for second reaction cycle under the samereaction conditions as before The results indicated that theyield decreased with the repeated use of the waste shell-derived catalysts and it exhibited poor catalytic activity afterbeing used for more than two times This deactivation wasprobably due to the structural changes leading to the failure tomaintain the form of CaO or its transformation to other formsuch as Ca(OH)
2 This may also be due to the losses of some
catalyst amount during the process of washing filtration andcalcination [25]
For biodiesel to be used in diesel engines the fuelmust meet various specifications stated in biodiesel standardmainly United States biodiesel standard (ASTM D6751) andEuropean biodiesel standard (EN14214) [26 27] The fuelproperties of FAME obtained in this work were summarizedin Table 3 along with a comparison to the recommendedbiodiesel international standards ASTMD6751 and EN14214The physicochemical properties assessed include kinematicviscosity (40∘C) density (80∘C) flash point cloud point pourpoint acid value and water content It can be seen that mostof its properties are in the range of fuel properties as describedin the latest standards for biodiesel [28]
4 Conclusions
Activated waste oyster and Pyramidella shells have beensuccessfully utilized as heterogeneous catalysts in themicrowave-assisted transesterification of Jatropha curcas oilThis catalyst contains CaCO
3which is converted to CaO
after calcination at temperatures 900∘C for 2 hThe optimumconditions which yielded a conversion of oil of nearly 93for both waste shell-derived catalysts were reaction time5min microwave power 800W methanoloil molar ratio 15and catalyst loading 4wt The experimental results showthat CaO catalyst had excellent activity and stability duringreaction The catalyst was used for 3 cycles and apparentlow activity loss was observed The activity of spent catalystcould be restored by recalcination process The physical andchemical properties of biodiesel produced conform to theavailable standards
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgments
This work is supported by the Silpakorn University Researchand Development Institute (SURDI 570151) The authorsacknowledge sincerely the Department of Materials Sci-ence and Engineering (MATSE) Faculty of Engineeringand Industrial Technology Silpakorn University (SU) andNational Center of Excellence for Petroleum Petrochemicals
Journal of Chemistry 7
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
and Advanced Materials (PPAM) Chulalongkorn University(CU) for supporting and encouraging this investigation
References
[1] J Boro D Deka and A J Thakur ldquoA review on solid oxidederived from waste shells as catalyst for biodiesel productionrdquoRenewable amp Sustainable Energy Reviews vol 16 no 1 pp 904ndash910 2012
[2] R Chakraborty S Bepari and A Banerjee ldquoApplication of cal-cined waste fish (Labeo rohita) scale as low-cost heterogeneouscatalyst for biodiesel synthesisrdquoBioresource Technology vol 102no 3 pp 3610ndash3618 2011
[3] P Khemthong C Luadthong W Nualpaeng et al ldquoIndustrialeggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel productionrdquo Catalysis Today vol 190 no 1pp 112ndash116 2012
[4] A Buasri N Chaiyut V Loryuenyong PWorawanitchaphongand S Trongyong ldquoCalcium oxide derived from waste shellsof mussel cockle and scallop as the heterogeneous catalyst forbiodiesel productionrdquo The Scientific World Journal vol 2013Article ID 460923 7 pages 2013
[5] C-YWei T-C Huang andH-H Chen ldquoBiodiesel productionusing supercritical methanol with carbon dioxide and aceticacidrdquo Journal of Chemistry vol 2013 Article ID 789594 6 pages2013
[6] B Sanjay ldquoHeterogeneous catalyst derived from naturalresources for biodiesel production a reviewrdquo Research Journalof Chemical Sciences vol 3 pp 95ndash101 2013
[7] W Suryaputra I Winata N Indraswati and S Ismadji ldquoWastecapiz (Amusium cristatum) shell as a new heterogeneous cat-alyst for biodiesel productionrdquo Renewable Energy vol 50 pp795ndash799 2013
[8] M Kouzu and J Hidaka ldquoTransesterification of vegetable oilinto biodiesel catalyzed by CaO a reviewrdquo Fuel vol 93 pp 1ndash122012
[9] N Viriya-empikul P Krasae B Puttasawat B Yoosuk NChollacoop and K Faungnawakij ldquoWaste shells of mollusk andegg as biodiesel production catalystsrdquo Bioresource Technologyvol 101 no 10 pp 3765ndash3767 2010
[10] A C Alba-Rubio F Vila D M Alonso M Ojeda R MariscalandM L Granados ldquoDeactivation of organosulfonic acid func-tionalized silica catalysts during biodiesel synthesisrdquo AppliedCatalysis B Environmental vol 95 no 3-4 pp 279ndash287 2010
[11] S T Jiang F J Zhang and L J Pan ldquoSodium phosphate asa solid catalyst for biodiesel preparationrdquo Brazilian Journal ofChemical Engineering vol 27 no 1 pp 137ndash144 2010
[12] A Buasri N Chaiyut V Loryuenyong C Rodklum T Chaik-wan and N Kumphan ldquoContinuous process for biodieselproduction in packed bed reactor from waste frying oil usingpotassium hydroxide supported on Jatropha curcas fruit shell assolid catalystrdquo Applied Sciences vol 2 pp 641ndash653 2012
[13] Y B Cho and G Seo ldquoHigh activity of acid-treated quaileggshell catalysts in the transesterification of palm oil withmethanolrdquo Bioresource Technology vol 101 no 22 pp 8515ndash8519 2010
[14] P-L Boey G P Maniam S A Hamid and D M H AlildquoUtilization of waste cockle shell (Anadara granosa) in biodieselproduction from palm olein optimization using responsesurface methodologyrdquo Fuel vol 90 no 7 pp 2353ndash2358 2011
[15] A Birla B Singh S N Upadhyay and Y C Sharma ldquoKineticsstudies of synthesis of biodiesel from waste frying oil using
a heterogeneous catalyst derived from snail shellrdquo BioresourceTechnology vol 106 pp 95ndash100 2012
[16] J Geist K Auerswald and A Boom ldquoStable carbon isotopes infreshwater mussel shells environmental record or marker formetabolic activityrdquo Geochimica et Cosmochimica Acta vol 69no 14 pp 3545ndash3554 2005
[17] S Hu Y Wang and H Han ldquoUtilization of waste freshwatermussel shell as an economic catalyst for biodiesel productionrdquoBiomass and Bioenergy vol 35 no 8 pp 3627ndash3635 2011
[18] N Viriya-Empikul P Krasae W Nualpaeng B Yoosuk andK Faungnawakij ldquoBiodiesel production over Ca-based solidcatalysts derived from industrial wastesrdquo Fuel vol 92 no 1 pp239ndash244 2012
[19] A Buasri N Chaiyut V Loryuenyong et al ldquoTransesterifi-cation of waste frying oil for synthesizing biodiesel by KOHsupported on coconut shell activated carbon in packed bedreactorrdquo ScienceAsia vol 38 no 3 pp 283ndash288 2012
[20] A Santana J MacAira and M A Larrayoz ldquoContinuousproduction of biodiesel using supercritical fluids a comparativestudy between methanol and ethanolrdquo Fuel Processing Technol-ogy vol 102 pp 110ndash115 2012
[21] C Samart P Sreetongkittikul and C Sookman ldquoHetero-geneous catalysis of transesterification of soybean oil usingKImesoporous silicardquo Fuel Processing Technology vol 90 no7-8 pp 922ndash925 2009
[22] D Salinas P Araya and S Guerrero ldquoStudy of potassium-supported TiO
2
catalysts for the production of biodieselrdquoApplied Catalysis B Environmental vol 117-118 pp 260ndash2672012
[23] B P Lim G P Maniam and S A Hamid ldquoBiodiesel fromadsorbed waste oil on spent bleaching clay using CaO as aheterogeneous catalystrdquo European Journal of Scientific Researchvol 33 no 2 pp 347ndash357 2009
[24] C Ngamcharussrivichai P Totarat and K Bunyakiat ldquoCaand Zn mixed oxide as a heterogeneous base catalyst fortransesterification of palm kernel oilrdquo Applied Catalysis AGeneral vol 341 no 1-2 pp 77ndash85 2008
[25] J Boro A J Thakur and D Deka ldquoSolid oxide derived fromwaste shells of Turbonilla striatula as a renewable catalyst forbiodiesel productionrdquo Fuel Processing Technology vol 92 no10 pp 2061ndash2067 2011
[26] H V Lee J C Juan and Y H Taufiq-Yap ldquoPreparationand application of binary acid-base CaO-La
2
O3
catalyst forbiodiesel productiordquo Renewable Energy vol 74 pp 124ndash1322015
[27] A Buasri B Ksapabutr M Panapoy and N Chaiyut ldquoSyn-thesis of biofuel from palm stearin using an activated carbonsupported catalyst in packed column reactorrdquoAdvanced ScienceLetters vol 19 no 12 pp 3473ndash3476 2013
[28] A Buasri B Ksapabutr M Panapoy andN Chaiyut ldquoBiodieselproduction from waste cooking palm oil using calcium oxidesupported on activated carbon as catalyst in a fixed bed reactorrdquoKorean Journal of Chemical Engineering vol 29 no 12 pp 1708ndash1712 2012
