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Elsevier Editorial System(tm) for Bioresource TechnologyManuscript Draft

Manuscript Number:

Title: Influence of Pyrolysis Temperature on Cadmium and Zinc Sorption Capacity of Sugarcane Straw-Derived Biochar

Article Type: Original research paper

Keywords: Heavy metals; Biomass; Tropical soils; Adsorption

Corresponding Author: Dr. Leonidas Carrijo Azevedo Melo,

Corresponding Author's Institution: Universidade Federal de Viosa

First Author: Leonidas Carrijo Azevedo Melo

Order of Authors: Leonidas Carrijo Azevedo Melo; Aline R Coscione; Cleide A Abreu; Aline P Puga;Otvio A Camargo

Abstract: The effect of pyrolysis temperature (400, 500, 600 and 700 oC) on the characteristics andmetal sorption capacity of sugarcane straw derived-biochar (BC) was investigated. By increasing thepyrolysis temperature there was a reduction in the O/C and H/C molar ratios. Sorption capacity ofbiochar pyrolyzed at 700 C was nearly four-times greater than that produced at 400 C. In the Entisolmixture there was an increase up to seven-fold in the sorption of both Cd and Zn, while in the Oxisolmixture there was a maximum 20% increase in sorption, compared to the control. For remediationpurposes of Cd and Zn contaminated substrates the use of higher pyrolysis temperature biochars arerecommended due to their higher metal sorption capacity.

S gg t d R i L M


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Suggested Reviewers: Lena Ma

All authors are in agreement with the submission of the manuscript. Also, themanuscript is original work and has not been submitted earlier to BITE or to any other

journal. In this work it is described a detailed characterization and the utilization, asmetal sorbent, of biochar produced from sugar cane residues. It was found that byincreasing the pyrolytic temperature the sorption of zinc and cadmium was enhancedgreatly both in aqueous solution and in soils. The sugarcane industry produces a hugeamount of biomass that can be used to generate electricity as well as biochar. Therefore,such results may help to encourage the use of this type of biomass for a different use,i.e. as metal sorbent with potential to reclaim areas contaminated by heavy metals.Subject Classification number 40: BIOMASS & FEEDSTOCK UTILIZATION

Cover Letter
http://popupclassificationdetail%28185%29/http://popupclassificationdetail%28185%29/


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HIGHLIGHTS

Pyrolysis temperature affected the physicochemical properties of biochar.

Higher pyrolysis temperature increased the capacity of biochar to sorb Cd and Zn.

The effect of biochar in the sorption of Cd and Zn is pronounced in sandy soils.

*Highlights (for review)


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Influence of Pyrolysis Temperature on Cadmium and Zinc Sorption1

Capacity of Sugarcane Straw-Derived Biochar2

3Lenidas C. A. Melo, a,* Aline R. Coscione, b Cleide A. Abreu, b Aline P. Puga b and Otvio4A. Camargo b 5a Departamento de Solos, Universidade Federal de Viosa, CEP 36570-000, Viosa, MG, Brazil. 6*Corresponding author: Tel.: +55 31 3899 1048; Fax.: +55 31 3899 2648. E-mail adress:[email protected] 8

b Centro de Solos e Recursos Ambientais, Instituto Agronmico de Campinas, CEP 13020 902, Campinas, SP,9 Brazil.10

11

ABSTRACT12

The effect of pyrolysis temperature (400, 500, 600 and 700 oC) on the characteristics and13

metal sorption capacity of sugarcane straw derived-biochar (BC) was investigated. By14

increasing the pyrolysis temperature there was a reduction in the O/C and H/C molar ratios.15

Sorption capacity of biochar pyrolyzed at 700 C was nearly four-times greater than that16

produced at 400 C. In the Entisol mixture there was an increase up to seven-fold in the17

sorption of both Cd and Zn, while in the Oxisol mixture there was a maximum 20%18

*ManuscriptClick here to view linked References
mailto:[email protected]:[email protected]://ees.elsevier.com/bite/viewRCResults.aspx?pdf=1&docID=41629&rev=0&fileID=1034748&msid={7255CC8D-5649-42D3-8955-49CDB686BBC5}http://ees.elsevier.com/bite/viewRCResults.aspx?pdf=1&docID=41629&rev=0&fileID=1034748&msid={7255CC8D-5649-42D3-8955-49CDB686BBC5}mailto:[email protected]


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chemical quality (Maia et al. 2011) and/or enhance carbon sequestration (Lehmann et al.28

2006). Most recently biochar has been considered as an option for remediation of heavy29

metals and organic pollutants contaminated soils, as reviewed by Beesley et al. (2011).30

Chemically, biochar is difficult to define due to the wide variety of biomass and31

charring conditions used in its production, which results in materials with a wide range of32

final characteristics (Lehmann and Joseph 2009). By increasing the pyrolysis temperature,33

there is a gradual increase in the aromaticity of the plant biomass, forming a continuum 34

from partially charred plant materials, to charcoal, soot and ultimately graphite (Preston and35

Schmidt 2006). In the range of temperature that biochar is produced (usually < 700 C),36

after an extensive characterization of grass and wood based biochar, Keiluweit et al. (2010)37

proposed a categorization based on its chemical and physical states during pyrolysis: (i)38

transition chars the crystalline character of the feedstock is preserved; (ii) amorphous39

chars - heat-altered molecules and incipient aromatic polycondensates are randomly mixed;40

(iii) composite chars - poorly ordered graphene stacks embedded in amorphous phases; and41


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in the environment that could an advantage to avoid field re-applications. Another51

mechanism of stability is the formation of mineral-biochar complexes related to increasing52

surface oxidation of the biochars during the aging, as observed by Lin et al. (2012) after53

incubation of an Fe rich soil (ferrosol) with biochars produced at 550 C.54

Chen et al. (2011) verified that corn straw-derived biochar pyrolyzed at 600 C55

adsorbed about twice as much of Cu(II) and Zn(II) from aqueous solution, as compared to a56

hardwood-derived biochar pyrolyzed at 450 C. On the other hand, Cao et al. (2009)57

observed that manure-derived biochar produced at 200 C (BC200) showed higher Pb58

sorption than the biochar formed at 350 C (BC350). This was mainly attributed to the59

precipitation of lead with soluble P, which was higher in BC200 than in BC350. Such60

research findings show that the use of biochar as metal sorbent depends strongly on the61

feedstock and pyrolysis conditions, and should be evaluated case-by-case.62

In Brazil, the sugarcane processing facilities convert the feedstock (sugarcane) into63

a variety of products such as sugar, bioethanol, electricity, and other by-products (Cavalett64


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sorption capacity is sought for future application of biochar to reclaim Zn contaminated73

mine soils.74

75

2. Material and Methods76

77

Sugarcane straw was collected in a field experiment, just after the harvest of78

sugarcane. The material was oven-dried at 60 C for 24h and placed in a pyrolyzer, sealed79

and heated to 400, 500, 600 and 700 C at the rate of 10 C/min. The desired temperature80

was held for about one hour (slow pyrolysis), after which the pyrolysed material was left to81

slowly cool down to room temperature. The weights of the starting biomass and of the82

resulting material (biochar - BC) were recorded to determine the BC yield. Biochar was83

ground to pass a stainless steel sieve (< 0.5 mm) and used for characterization and84

subsequent experimentation. A clay-rich Oxisol and an Entisol were used in the batch85

sorption experiments.86


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and two portions of 20 mL of the acetate solution. The excess solution (non-adsorbed96

NH 4+) was washed out with three portions of 30 mL of isopropyl alcohol. The biochar was97

rinsed with four portions of 50 mL of 1M KCl solution and the rinsate was collected and98

brought to the final volume of 250 mL and the NH 4+ was determined by the Kjeldahl99

method.100

Prior to the analysis of the point of zero charge (pH pzc ), the ash of biochar samples101

was removed by washing with 0.1 M HCl (27 g L -1) by constant stirring for 1 h, then the102

material was rinsed three times with distilled deionized water (DDW) and dried overnight103

at 80 C (Uchimiya et al. 2011b). The pH pzc was determined as described by Yang et al.104

(2004). In 60 mg of BC were added 20 mL of 0.01M CaCl 2 solution previously adjusted105

with diluted HCl or NaOH solutions to pH 4, 6, 8 and 10. After shaking for 24 h the pH106

was measured and when the final pH was equal to the initial pH (line 1:1) it was considered107

as pH pzc . The CHN elemental composition was determined in an elemental analyzer (Perkin108

Elmer series II 2400). The oxygen contents were estimated by mass difference, i.e. 100% -109


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119

2.2 FT-IR and thermal analysis120

121

Surface functional groups of BC were analyzed by Fourier transform-infrared122

spectroscopy (FT-IR, Spectrum One, Perkin Elmer), in the range of 4000 to 450 cm -1, by123

using 20 scans/min at 4 cm -1 resolution. Measurements were performed in pellets of BC124

blended with KBr.125

Thermogravimetric analysis of BC was performed in a TGA 2050 TA Instrument.126

The measurements were obtained under N 2 atmosphere from room temperature up to 950127

C at a heating rate of 20 C/min. Samples mass varying from 5.1 to 5.7 mg were used.128

129

2.3 Scanning Electron Microscopy130

131

Analysis of Scanning Electron Microscope (SEM) was carried out using a LEO Evo132


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extracted with a 1 M KCl solution and measured by titration with a 0.025 M NaOH142

solution. Phosphorus, Ca, Mg and K were extracted by ionic exchange resin and determined143

by ICP OES. The cation exchange capacity (CEC) was calculated as the sum of cations (Ca144

+ Mg + K + H + Al). Total acidity (H+Al) was estimated at pH 7.0 with buffer SMP145

solution. Available sulfur was extracted by Ca(H 2PO 4)2 0.01 M and determined146

turbidmetrically, after reaction with BaCl 2.2H 2O. Soil available concentrations of Cu, Fe,147

Mn and Zn were extracted with DTPA pH 7.3 (Lindsay and Norvell, 1978). Boron was148

extracted by hot water and determined colorimetrically. For a more detailed149

characterization of these soils see Melo et al. (2011).150


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2.5 Batch sorption experiments151

152

Sorption experiments were carried out following the procedures described by153

Uchimiya et al. (2011c), with modifications. Briefly, 0.2 g of BC or 2.0 g of soil + BC154

mixture (1.8 g of Oxisol or Entisol + 0.2 g of BC) were weighted into 50 mL centrifuge155

tubes, in duplicate. Then, 20 mL of synthetic rainwater (SR - obtained by addition of 10156

mM H 2SO 4 in deionized water until pH 4.5 was reached) were added to the sample and157

shaken horizontally for 24 h at 100 oscillations/min. After, 200 L of a 0.2 M stock158

solution of Cd or Zn were added in order to reach a final concentration of 2 mM and the159

tubes were shaken for another 24 h, and subsequently filtered. In the equilibrium solution160

Cd or Zn were measured by ICP-OES. Control treatments were achieved by using blank161

reagents in all batch procedures. Tests of sorption using longer times (i.e. 48 h and 96 h)162

were performed and showed no significant difference (data not shown), confirming the163

duration (24 h) was adequate for equilibration.164


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pH and electrical conductivities was observed, probably reflecting the greater ash content174

of biochar obtained at higher pyrolysis temperatures.175

The cation exchange capacity (CEC) reduced, while the increase of the carbon176

content corresponded to a decrease of O and H was observed at higher pyrolysis177

temperatures. Consequently there was a reduction in the O/C and H/C molar ratios. The178

reduction in CEC is probably related to loss of O containing functional groups. Such179

findings are in agreement with other authors (Singh et al., 2010; Mukherjee et al. 2011;180

Uchimiya et al. 2011a; Song and Guo 2012) that also observed similar results for the effect181

of temperature on these biochar parameters, produced from various biomasses suggesting182

that variations in these parameters with temperature occurs regardless of the parent biomass183

and seems to be a general rule. 184

The molar ratios obtained from the elemental analysis are commonly used to185

determine the degree of aromaticity (H/C) and polarity (O/C) of coal and have been used186

for biochar characterization (Uchimiya et al. 2011a) since by increasing the pyrolysis187


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expected to be more available. The relatively high levels of Ca, Mg and K in all BCs tested197

are due to the sugarcane straw s initial composition, which is rich in such elements, mainly198

K (Oliveira et al., 2002). It should be noted that since this BC presents alkaline reaction199

(pH ranging from 8.6 to 10.1) and is rich in nutrients, such factors indicate its good200

potential for reclaiming contaminated land, since it could act as a metal immobilizer and a201

nutrient supplier, allowing the growth of plants in bare soils. Such characteristics make this202

particular biochar an attractive option for this purpose. Al-Wabel et al. (2013) verified203

enrichment of 232%, 199% and 304% for Ca, Mg, K, respectively, for biochar produced204

from conocarpus wastes at 800 C. They concluded that such an increase in alkaline205

elements could be responsible for liming effects induced by biochar pyrolyzed at high206

temperatures.207

The FTIR spectra revealed in all cases bands at the region of 3500 to 3400 cm -1,208

which relates to stretches of hydroxyl groups and indicates hydrogen bonds (Figure 1). The209

bands between 2900 and 2800 cm -1 are related to the elongation of CH aliphatic chains.210


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decrease in the intensity of the peaks of different groups, which is consistent with the lower219

O contents of biochars at higher temperatures.220

The mass loss at different TGA stages analysis of the biochar samples are presented221

in Table 2. For all samples considered the stage 1, around 100 C, was observed and it is222

consistent with the loss of water (moisture) from samples. With the increase of furnace223

temperatures occurred a plateau until around 380 C (400 BC) and 450 C (700 BC), in224

which no effective loss of mass was observed. After, at stage 3 there was a sudden drop, of225

approximately 50% sample weight loss, up to 640 C. An exception here is the BC700, in226

which the mass loss is relatively low (23.7%) at stage 3, as compared to biochar samples227

obtained at lower temperatures. The mass loss at this range of temperature is related to the228

decomposition of organic remaining content of the BC samples, including cellulose and229

hemicellulose. The latter starts to decompose from 220 C up to 315 C, and it is followed230

by cellulose decomposition (Yang et al. 2007).231Finally, a loss of approximately 20% of samples mass that has occurred between232


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Furthermore, the surface properties of materials are also important to explain its240

reactivity. In general, the surface morphology of the sugarcane straw biochar samples,241

despite the temperature it is produced at, showed an irregular amorphous surface with a242

porous structure (Figure 2). This effect could be the result of melting and fusion process of243

the lignin and other small molecules compounds, such as pectin and inorganic compounds,244

as was described by Liu et al. (2010) in pinewood biochar produced at 300 C and 700 C.245

246

3.2 Adsorption of Cd and Zn in soils247

248

The Oxisol and the Entisol used for experimentation were slightly acidic and had249

contrasting characteristics, mainly governed by the clay content/fraction (63% for the250

Oxisol x 6% for the Entisol), CEC and organic matter content (Table 3). The lower251

available P and micronutrient (i.e. Cu, Fe, Mn and Zn) contents in the Oxisol as compared252

to the Entisol, indicate a naturally higher sorption capacity of the Oxisol.253


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removal from aqueous solution with biochar produced from a giant Miscanthus at higher263

pyrolysis temperature. Jiang et al. (2012) observed that the application of rice straw derived264

biochar in an Ultisol increased soil pH, making the surface charge more negative, and265

significantly reduced the acid soluble Cu(II) and Pb(II). They also found that the functional266

groups (i.e. -COOH e -OH) of the biochar formed stable complexes mainly with Cu(II),267

enhancing greatly its adsorption.268

Interesting results were found when biochar was mixed into the soils, as related to269

Cadmium (Cd) or Zinc (Zn) sorption (Figures 3B and 3C). The addition of 10% BC to the270

Oxisol increased the adsorption of either Cd or Zn up to 20%, as compared to the control.271

As discussed above the Oxisol is clay-rich and naturally exhibits a relatively high sorption272

capacity. Even so, BC played a role to increase metal sorption capacity in this soil. When273

BC was applied to the Entisol there was an increase up to seven-fold the sorption of both274

cations, as compared to the control (without BC). Uchimiya et al. (2011c) also found275

similar results for Cu retention in two soils (Norfolk and San Joaquin), with distinct276


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functional groups that are able to retain cationic metals. On the other hand, results from286

Uchimiya et al. (2011a) show that biochar formed at lower temperature (350 C) was more287

effective to retain heavy metals in an acidic and eroded soil than biochar formed at higher288

temperatures. They concluded that surface functional groups of biochars (which govern289

pH pzc and VM and oxygen contents) control their ability to retain heavy metals in the soil 290

Therefore; they stated that biochar selection for soil amendment must be made case-by-291

case based on the biochar characteristics, soil property, and the target function . In this292

particular case, the pH pzc of the BC at 350 C was the only one unit below the equilibrium293

pH. The higher is the difference between pH pzc and equilibrium pH the higher are expected294

to be the electrostatic interactions between cationic metal species and negatively charged295

surfaces (Uchimiya et al. 2011a), which in our case is for BC at 700 C, helping to explain296

its higher metal sorption.297

Uchimiya et al. (2012), however, found that BC poultry litter pyrolyzed at 350 C298

was better to retain and stabilize Pb in a contaminated soil than the BC produced at 650 C.299


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increased the capacity of sugarcane straw-derived biochar to sorb Cd and Zn. The effect of309

biochar in the sorption of Cd and Zn is much more pronounced in sandy soils with low310

natural ability to retain metal pollutants than in clayey soils. The specific intention being311

the application of sugarcane straw-derived biochars to Zn contaminated mine soils higher312

pyrolytic temperatures are recommended.313

314

Acknowledgments315

316

The authors are grateful for the financial support of the So Paulo Research317Foundation FAPESP (Grant. No. 2011/12346-3) and for the postdoctoral fellowship318

(Grant. No. 2011/02844-6) for the first author. We also are grateful to Prof. J.O. Brito319

(Esalq/USP) for kindly provide the biochar for the study and Dr. Luke Beesley (The James320

Hutton Institute) for the helpful comments on the article.321

322


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Cavalett, O., Junqueira, T.L., Dias, M.O.S., Jesus, C.D.F., Mantelatto, P.E., Cunha, M.P.,333

Franco, H.C.J., Cardoso, T.F., Maciel Filho, R., Rossell, C.E. V., Bonomi, A., 2011.334 Environmental and economic assessment of sugarcane first generation biorefineries in335Brazil. Clean Technol. Environ. Policy 14, 399 410.336

Chen, X., Chen, G., Chen, L., Chen, Y., Lehmann, J., McBride, M.B., Hay, A.G., 2011.337Adsorption of copper and zinc by biochars produced from pyrolysis of hardwood and338corn straw in aqueous solution. Bioresour. Technol. 102, 8877 8884.339

Ferreira-Leito, V., Gottschalk, L.M.F., Ferrara, M.A., Nepomuceno, A.L., Molinari,340H.B.C., Bon, E.P.S., 2010. Biomass residues in Brazil: availability and potential uses.341Waste Biomass Valorization 1, 65 76.342

Fuertes, A.B., Arbestain, M.C., Sevilla, M., Maci-Agull, J.A., Fiol, S., Lpez, R.,343Smernik, R.J., Aitkenhead, W.P., Arce, F., Macias, F., 2010. Chemical and structural344

properties of carbonaceous products obtained by pyrolysis and hydrothermal345carbonisation of corn stover. Aust. J. Soil Res. 48, 618 626.346

Jiang, J., Xu, R., Jiang, T., Li, Z., 2012. Immobilization of Cu(II), Pb(II) and Cd(II) by the347addition of rice straw derived biochar to a simulated polluted Ultisol. J. Hazard. Mater.348229-230, 145 150.349

Keiluweit, M., Nico, P.S., Johnson, M.G., Kleber, M., 2010. Dynamic molecular structure350of plant biomass-derived black carbon (biochar). Environ. Sci. Technol. 44, 1247 3511253.352

Kim, W.-K., Shim, T., Kim, Y.-S., Hyun, S., Ryu, C., Park, Y.-K., Jung, J., 2013.353


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Liu, Z., Zhang, F.-S., Wu, J., 2010. Characterization and application of chars produced366

from pinewood pyrolysis and hydrothermal treatment. Fuel 89, 510 514.367

Maia, C.M.B.F., Madari, B.E., Novotny, E.H., 2011. Advances in biochar research in368Brazil. Dynamic Soil, Dynamic Plant 5 (Special Issue 1), 53-58.369

Melo, L.C.A., Alleoni, L.R.F., Carvalho, G., Azevedo, R.A., 2011. Cadmium- and barium-370toxicity effects on growth and antioxidant capacity of soybean (Glycine max L.)371

plants, grown in two soil types with different physicochemical properties. J. Plant372

Nutr. Soil Sci. 174, 847 859.373

Mukherjee, a., Zimmerman, a. R., Harris, W., 2011. Surface chemistry variations among a374series of laboratory-produced biochars. Geoderma 163, 247 255.375

Oliveira, M.W., Trivelin, P.C.O., Boareto, A.E., Muraoka, T., Mortatti, J., 2002. Leaching376of nitrogen , potassium , calcium and magnesium in a sandy soil cultivated with377sugarcane. Pesqui. Agropecu. Bras. 37, 861 868.378

Preston, C.M., Schmidt, M.W.I., 2006. Black (pyrogenic) carbon: a synthesis of current379knowledge and uncertainties with special consideration of boreal regions.380Biogeosciences 3, 397 420.381

Quirk, R.G., Zwieten, L., Kimber, S., Downie, A., Morris, S., Rust, J., 2012. Utilization of382 biochar in sugarcane and sugar-industry management. Sugar Tech 14, 321 326.383

Raij, B. van, Andrade, J.C., Cantarella,H., Quaggio, J.A., 2001. Chemical analysis to384evaluate the fertility of tropical soils (in Portuguese), Instituto Agronmico de385


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Uchimiya, M., Klasson, K.T., Wartelle, L.H., Lima, I.M., 2011c. Influence of soil398

properties on heavy metal sequestration by biochar amendment: 1. Copper sorption399 isotherms and the release of cations. Chemosphere 82, 1431 1437.400

Uchimiya, M., Wartelle, L.H., Klasson, K.T., Fortier, C. a, Lima, I.M., 2011a. Influence of401 pyrolysis temperature on biochar property and function as a heavy metal sorbent in402soil. J. Agric. Food Chem. 59, 2501 2510.403

Wu, W., Yang, M., Feng, Q., McGrouther, K., Wang, H., Lu, H., Chen, Y., 2012. Chemical404

characterization of rice straw-derived biochar for soil amendment. Biomass Bioenergy40547, 268 276.406

Yang, H., Yan, R., Chen, H., Lee, D.H., Zheng, C., 2007. Characteristics of hemicellulose,407cellulose and lignin pyrolysis. Fuel 86, 1781 1788.408

Yang, Y., Chun, Y., Sheng, G., Huang, M., 2004. pH-dependence of pesticide adsorption409 by wheat-residue-derived black carbon. Langmuir 20, 6736 41.410

411

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Figure 1. FTIR spectra of sugarcane straw derived biochar pyrolyzed at four temperatures.424

425

Figure 2. Scanning Electron Microscope (SEM) images of biochar. The images show426

biochars produced at 400C (a; c) and 700C (b; d), at 200x (a; b) and 1000x magnification427

(c; d).428

429

Figure 3. Adsorption of Cadmium and Zinc in biochars prepared at different temperatures430

(A); and adsorption of Cadmium (B) or Zinc (C) in an Oxisol and an Entisol alone or mixed431

with 10 % (w/w) biochar pyrolyzed at different temperatures. *Fig. B has the same legend432

as Fig. C433

434Table 1435Characterization of the Biochar436Parameter Pyrolysis Temperature (C)

400 500 600 700

Yield (%, w/w) 45 38 35 31EC (mS cm -1) 3.3 3.8 3.4 5.1

pH H2O 8.6 9.8 9.7 10.1


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Table 2440

Temperature range and mass loss for TGA in biochar samples441 Samples Stage 1 Stage 2 Stage 3 Stage 4 Totalmassloss(%)

Temp.range(C)

Massloss(%)

Temp.range(C)

Massloss(%)

Temp.range(C)

Massloss (%)

Temp.range(C)

Massloss(%)

BC400 < 96 2.4 96-378 6.1 378-641 45.5 641-950 24.1 78.1BC500 < 99 2.2 99-410 5.7 410-677 50.1 677-950 23.4 81.3BC600 < 96 2.0 96-439 4.3 439-683 44.8 683-950 24.5 75.6BC700 < 114 3.2 114-451 3.5 451-648 23.7 648-950 29.8 60.2

442443

Table 3444Characterization of the soils used in the sorption experiment445Soil pH SOM CEC Al Ca Mg K

CaCl 2 (g kg- ) ----------------------------mmol c kg

- ----------------------------Oxisol 5.7 0.0 37 2 94 7 - 39 2 26 2 1.4 0.1Entisol 5.2 0.2 23 2 69 4 1.4 0.1 28 1 1.9 0.8 0.6 0.1

P S Cu Fe Mn Zn B----------------------------------------------------mg kg - -------------------------------------------------------

Oxisol 3.9 0 60 3 0.7 0.1 39 1 14 2 0.5 0.1 0.3 0Entisol 173 6 15 1 3.0 0.1 130 13 28 1 11 0.1 1.0 0Values are mean (n = 3) standard deviation. SOM = Soil Organic Matter; CEC = Cation Exchange Capacity; - not446detected 447

448449450451

Figure


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Wavenumber (cm -1)

5001000150020002500300035004000

BC 400

BC 500

BC 600

BC 700

O-H3430

C=C

C-H aliphatic

Absorbance

C-H 2C-O-C

C-Haromatic

29182850

16181438

1112

874-810

g

Figure


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200 m

b

100 m

a

20 m

dc

20 m

Figure


26/26

T t t

Adsorbed metal (mg g

-1)

O x i s o lE n t i s o l

S 4 0 0 5 0 0 6 0 0 7 0 0

0 .0

0 .5

1 .0

1 .5

2 .0

2 .5

3 .0Z i n c

b

a a a a

c

b b b

a

T r e a t m e n t s


-1)

S 4 0 0 5 0 0 6 0 0 7 0 00 .0

0 .5

1 .0

1 .5

2 .0

2 .5

3 .0C a d m i u m

b

a a a a

c

b a b a b

a

P y r o l y s i s te m p e r a t u r e ( C )

4 0 0 5 0 0 6 0 0 7 0 0


-1)

0

4

8

1 2

1 6

2 0

C d

Z n

b

b

b

b

b

b

a

a

Date post:	04-Jun-2018
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Biocarvao Leon

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