Hindawi Publishing CorporationInternational Journal of Chemical EngineeringVolume 2013, Article ID 475303, 3 pageshttp://dx.doi.org/10.1155/2013/475303
EditorialToward Green Chemical Engineering
Antonia Pérez de los Ríos,1 Francisco José Hernández Fernández,2 María Gómez Gómez,1
Said Galai,3 and Pascual Pérez Ballesta4
1 Chemical Engineering Department, Faculty of Chemistry, University of Murcia, 30071 Murcia, Spain2 Chemical & Environmental Engineering Department, School of Industrial Engineering, Technical University of Cartagena,Murcia, 30202 Cartagena, Spain
3 Laboratory of Protein Engineering and BioactiveMolecules (LIP-MB), National Institute of Applied Sciences and Technology (INSAT),University of Carthage, North Urban Center, BP676-1080 Tunis, Tunisia
4Air and Climate Unit, Institute for Environment and Sustainability, European Commission, Joint Research Centre,TP 441, 21027 Ispra, Italy
Correspondence should be addressed to Antonia Perez de los Rıos; [email protected]
Received 29 October 2013; Accepted 29 October 2013
The chemicals industry and other related industries supply uswith a huge variety of essential products to everyday living.However, these industries have the potential to seriouslydamage our environment. In the last decade, the scientificcommunity has witnessed a growing interest in environ-mental issues and the value of environmentally friendlyenergy generation and chemical processes. The combinationof chemical engineering tools with the findings of greenchemists, biologists, and environmental scientists has allowedthe design of new processes for themanufacture of chemicals,fuels, and products with amuch reduced environmental foot-print. Furthermore, the developed environmentally benignalternative technologies have been proven to be economicallysuperior and function as well as or better than more toxictraditional options.
In the call for papers, we invited contributions thatpromote the design and efficient use of environmentallybenign chemical processes, including the development ofprocesses that use clean solvents and renewable resources,biocatalysis, alternative reactors, and innovative environ-mental technologies for water treatment and pollution con-trol. All contributions were peer-reviewed according to theusual high standards of this journal. Our thanks go to highlyqualified and thorough referees that helped us accept sevenpapers. They greatly contributed to the high quality of thefinal papers. In the following, a brief overview and summaryof the individual contributions are given.
The first contribution in this issue from G. R. L. Samana-mud et al. (University of Sao Paulo, Brazil) is entitled “Theapplication of a surface response methodology in the solar/UV-induced degradation of dairy wastewater using immobilizedZnO as a semiconductor.” An Advanced Oxidation Process(AOPs) was carried out in this study with the use ofimmobilized nanometric ZnO and solar/UV as energy sourceto degrade dairy wastewater. Experiments were performedbased on a surface response methodology in order to opti-mize the photocatalytic process. Degradation was measuredin percentage terms by total organic carbon (TOC).The entryvariables were ZnO coating thickness and pH using threelevels of each variable. The optimized results showed a TOCdegradation of 31.7%. Optimal parameters were metal-platecoating of 100 𝜇m of ZnO and pH of 8.0. Since solar/UV is aconstant and free energy source in most tropical countries,this process suggests an elevated potential contribution indairy wastewater treatment, especially as a pretreatment. Inaddition, authors suggest that nanometric ZnO can be usednot only for dairy wastewater treatment, but also for othertypes of industrial wastewater such as in the treatment of dyeindustry effluents, since 50% of color removal was reached inthe dairy effluent.
The paper by D. Jing et al. (Chalmers University ofTechnology, Sweden) is entitled “Examination of perovskitestructure 𝐶𝑎𝑀𝑛𝑂
3−𝛿with MgO addition as oxygen carrier for
chemical looping with oxygen uncoupling using methane and
2 International Journal of Chemical Engineering
syngas.” These authors produce cheap and environmentallyfriendly Ca-Mn combined oxides with MgO additions withgeneral formula CaMn
𝑥Mg1−𝑥
O3using the spray-drying
method and sintering at different temperatures. These newoxygen carriers were examined for chemical looping withoxygen uncoupling (CLOU). The active compound in theoxygen carriers was likely the perovskitematerial CaMnO
3−𝛿,
and it showed highly promising results with respect toreactivity and stability. Generally, average methane conver-sion above 97%, full syngas conversion, and substantialCLOUproperties were recognized at the tested temperatures,ranging from 900∘C to 1050∘C. It is worthy to note also thegood stability showed for CaMn
0.8Mg0.2O3sintered at 1300∘C
in 50 cycles’ tests. The very high reactivity with fuel gases,comparable to that of baseline oxygen carriers of NiO, makesthese perovskite particles highly interesting for commercialChemical-LoopingCombustion (CLC) application. Contraryto NiO, oxygen carriers based on CaMnO
3−𝛿have no ther-
modynamic limitations for methane oxidation to CO2and
H2O, not to mention that the materials are environmentally
friendly and can utilize much cheaper raw materials forproduction.
The paper “Carbonic anhydrase: an efficient enzyme withpossible global implications” by C. D. Boone et al. (Uni-versity of Florida, Florida, USA) highlights some of therecent accomplishments in the use of a family of enzymesknown as the carbonic anhydrases (CAs) to help lower CO
2
atmospheric emissions and promote biofuel production. CAsreversibly catalyze the hydration of CO
2into bicarbonate,
and they are fairly inexpensive to produce and reuseable andcan work at ambient temperatures. The authors proposedan optimized system that would include a cyclic productionof biofuels via algal and/or microalgal cultures that wouldsubstitute for fossil fuel combustion. The flue gas could thenbe scrubbed for CO
2by the CAs in the same algal cultures,
which would also promote the formation of bicarbonate,inducing further biomass production and increasing the rateof calcite precipitation. As such, this system would providethe benefits of reducedCO
2emissionswhile also providing an
essentially self-enclosed fuel and calcite generator, providedthat other essential ingredients and nutrients are available.
N. Lerkkasemsan andL. E. K.Achenie (Virginia Polytech-nic Institute and State University, VA, USA) contribute to thisissue of the journal with their paper “Life cycle costs and lifecycle assessment for the harvesting, conversion, and the use ofswitchgrass to produce electricity.” This work considers bothlife cycle assessment and the life cycle costs of the pyrolysisof switchgrass to use as an energy source in a conventionalpower plant. The process consists of cultivation, harvesting,transportation, storage, pyrolysis, transportation, and powergeneration. In the last step, pyrolysis oil is converted toelectric power through cocombustion in conventional fossilfuel power plants. The authors found that greenhouse gas(GHG) emission from the system was negative. Therefore,based on life cycle assessment, the power generation usingpyrolysis oil is environmentally friendly since it reducesGHG emissions. On the other hand, life cycle cost analysisreveals that the electricity cost per kwh is higher than theconventional technology which uses fossil fuels. However,
based on the analysis, the electricity cost from pyrolysis oilcould be competitive if we can utilize the system with thecheapest scenarios. They proposed a circular field entirelyfilled with switchgrass as the optimal scenario for reducingelectricity cost because of the lower cost of cultivation,harvesting, and transport.
The next contribution in this issue from X. Zhang et al.(Sichuan University, China) is entitled “Research of hydrogenpreparation with catalytic steam-carbon reaction driven byphoto-thermochemistry process.”The authors have studied thehydrogen preparation from steam-carbon reaction catalyzedby K2CO3at 700∘C, which was driven by the solar reaction
system simulated with the Xenon lamp. They found that therate of reaction with the catalyst was 10 times more than thatwithout catalyst, although there was no obvious change forthe rate of hydrogen generation with catalyst content rangefrom 10% to 20%. It is worthy to note that the conversionefficiency of solar energy to chemical energy in this system ismore than 13.1% over that by photovoltaic-electrolysis route.An analysis to the mechanism of catalytic steam-carbonreaction with K
2CO3is also given by the authors.
The paper by T. R. S. Baumgartner et al. (UniversidadeEstadual de Maringa, Brazil) is entitled “Biomass productionand ester synthesis by in situ transesterification/esterificationusing the microalga Spirulina platensis.” The production ofbiomass from microalgae is relatively simple, it requires lightand a nutrient source, and reaches high productivity in ashort time. In this work, the authors have analyzed thebiomass production from the microalga Spirulina platensisand its subsequent use for in situ synthesis of alkyl estersvia acid transesterification/esterification of biomass to pro-duce biodiesel. They found the best result using ethanol asalcohol and n-hexane as a cosolvent. In situ transesterifica-tion/esterification for ester formation, aiming at producingbiodiesel, adds unconventional dynamics to the use of thisfeedstock, in particular due to the reduction in reaction timeand volume of solvents used in the process.
The last contribution in this special issue is from G.Severa et al. (University of Hawaii, Hawaii, USA) and isentitled “Corecovery of bio-oil and fermentable sugars fromoil-bearing biomass.” In this work, an ionic liquid-methanolco-solvent was shown for the first time to effectively extractbio-oil and recover fermentable sugars fromoil-seed biomass.This represents an improvement over current approaches thathave focused solely on the recovery of bio-oil or fermentablesugars. Effective corecovery of both bio-oil and fermentablesugars was shown to require both cosolvent componentswith an optimal concentration of 70–30wt% ionic liquid 1-ethyl-3-methylimidazolium acetate to methanol ratio and aprocessing temperature of 120∘C. Under these conditions,nearly all the bio-oil (35.8 and 24.1 wt % relative to weight ofwhole seed) was extracted and autopartitioned to a separateimmiscible phase, and approximately 25.4 and 14.3 wt %(relative to weight of whole seed) of fermentable sugarswere recovered from the safflower and jatropha whole seeds,respectively. This constitutes a combined carbohydrate andbio-oil corecovery of 61.2 and 38.4 wt% of the safflower andjatropha whole seeds, demonstrating a new pathway forprocessing increased products from oil-seed biomass. A first
International Journal of Chemical Engineering 3
pass model analysis suggested that the most optimal process-ing pathwaywould be to pretreat the jatrophawhole seedwiththe co-solvent and recover bio-oil, fermentable sugars, and aprotein rich meal.
The collection of works in this special issue constitutesone more step forward in the race for the development ofdesired, greener, more sustainable chemical processes. Weare confident that much more advancements in this field willbe seen in the coming years. These advancements will bringgreat research opportunities and excitement to researchersand practitioners working in this field and will in the sametime make our living environment safer and more pleasant.We hope that you find these papers interesting and wish youmuch success in your research in the field of green chemicalengineering.
Acknowledgments
TheGuest Editors dedicate this special issue to the professorswho founded the Department of Chemical Engineering atthe University of Murcia: Antonio Soler Andres, AntonioBodalo Santoyo, Demetrio Gomez Perez, Agustın MinanaAznar, Manuel Rubio Torres, and Jose Saez Mercader. Wethank them for acting as a professional and personal referencefor us. Thank you.
Antonia Perez de los RıosFrancisco Jose Hernandez Fernandez
