Presentation on theme: "Use of chemical and physical characteristics to investigate trends in biochar feedstocks Fungai Mukome, Xiaoming Zhang, Lucas C.R. Silva, Johan Six,"— Presentation transcript:
1Use of chemical and physical characteristics to investigate trends in biochar feedstocks Fungai Mukome, Xiaoming Zhang, Lucas C.R. Silva, Johan Six, and Sanjai J. ParikhUniversity of California, DavisUS Biochar Conference, Rohnert Park, CAJuly 2012
3All biochars are not created equal…. (McLaughlin et al. 2009) Differ onpHSurface areaAsh contentWater holding capacityCation exchange capacity (CEC)H/C ratioC/N ratioThe top 3 are usually proprietaryFeedstock choice based on locally available resources – airborne loss, transportation costs and reduced carbon footprintAll a function of pyrolysis temperature (highest treatment temperature-HTT), pyrolysis method, residence time and feedstock
4ObjectivesTo characterize physical and chemical properties of various biochars (mostly commercially available)To determine if trends exist for biochar properties that can be related to feedstock material, which can serve to develop guidelines for biochar use.
5Objectives 1 Twelve biochars were analyzed Physical properties: Moisture contentAsh contentBET Surface areaSurface morphologyChemical properties:Elemental contentH and C contentpHCation exchange capacitySurface basicity and aciditySurface functionality (ATR-FTIR and Raman)
6Physical properties Char Source Material Pyrolysis Temp (°C) Ash (wt %)BET Surface Area (m2/g)Type (Hysteresis)BC_ ATurkey litter6421.8aPs. II (H3)BC_BbWalnut shell90040.4227.1Ps. II (H4)BC_CInoculated materialunavailablec15.595.9BC_DSoft wood2.425.2BC_EWood + Algal digestate6.42Ps. II (H3)BC_FWood5103165.8BC_G4102.62.8BC_HWood chips174.9BC_Iunavailable5164.1BC_J153.1BC_K5.5154.4BC_L4.2301.6Separate intoa Ps.II = Pseudo Type IIb Unknown, not willing to provide or proprietaryc Not commercially availableWoodNon-wood
7Scanning Electron Microscopy analysis SEM images of three biochars showing a) a char with type H3 hysteresis loop b) a char with type H4 hysteresis loop and c) a char with high ash content.c) BC_Ba) BC_Gb) BC_F10µm100µm60µmType II isotherms - capillary non-porous or macroporous adsorbents and represent monolayer-multilayer adsorption.Lower surface areas (BC_J,BC_H, BC_A and BC_G) - Type H3 hysteresis loops - lack of microporosity, plate-like particles and slit shaped pores.Higher surface area - (BC_L, BC_K, BC_J, BC_I, BC_F) - Type H4 hysteresis loops- narrow slit-like pores
9Greater aromaticity in wood derived biochar FTIR: Fourier Transform Infrared SpectroscopyAromaticC=CC-HAliphatic/FunctionalizedC-O, C-HC-OC=OGreater aromaticity in wood derived biochar
10xAliphatic ether (1029cm-1) xAromatic carbonyl (1690cm-1) CharxAromatic C-H (744cm-1)xAliphatic ether (1029cm-1)xAliphatic CH3 (1417cm-1)xAromatic C=C (1587cm-1)xAromatic carbonyl (1690cm-1)BC_A-2.910.210.02BC_B1.12.2BC_C0.533.60.380.690.39BC_D0.632.672.462.61.2BC_E0.272.832.050.94BC_F2.091.72.30.28BC_G2.160.831.50.4BC_H1.121.711.780.41BC_I1.831.98BC_J0.711.671.410.36BC_K1.051.171.61.9BC_L1.011.220.12x. Ratios of peak intensities relative to the aromatic C-H stretch at 870cm-1 common to all spectra
11ID - sp2 disordered C atoms in aromatic ring structures CharAliphatic ether (1029cm-1)yRaman Id/IgBC_A2.90.4BC_B1.10.34BC_C3.60.76BC_D2.670.58BC_E2.830.65BC_F2.09BC_G2.160.25BC_H10.83BC_I1.20.68BC_J1.670.72BC_K1.170.59BC_L1.010.71y. Ratio of peak intensities of the Carbon D (1350cm-1) and G (1690cm-1) bands in Raman spectraID - sp2 disordered C atoms in aromatic ring structuresIG - sp2 disordered C atoms in aliphatic and olefinic moleculesApproximates sp2: sp3 ratio in amorphous carbonD band(aromatic)G band(aliphatic & olefinic)
12Objective 2van Krevelen diagram of a) selected biochar (from literature) and b) 12 study biochar (inset)1. Sharma et al. Fuel 2004, 83,2. Keiluweit et al. Environmental Science & Technology 2010, 44,3. Zheng et al. Journal of Hazardous Materials 2010, 181,4. Cao, X. et al. Bioresource Technology 2010, 101,5. Özçimen et al. Renewable Energy 2010, 35,6. Jindarom et al. Chemical Engineering Journal 2007, 133,7. Chan et al. Soil Research 2008, 46,8. Azargohar et al. Applied Biochemistry and Biotechnology 2006, 131,9. Wu et al. Industrial & Engineering Chemistry Research 2009, 48,10. Toles et al. Bioresource Technology 2000, 71,11. Van Zwieten et al. Plant and Soil 2010, 327,12. Chen, B. and Chen, Z. Chemosphere 2009, 76,13. Major et al. Plant and Soil 2010, 333,14. Argudo, M. et al. Carbon 1998, 36,15. Hammes et al. Applied Geochemistry 2008, 23,16. Chun et al. Environmental Science & Technology 2004, 38,17. Mahinpey et al. Energy & Fuels 2009, 23,18. Rondon et al. Biology and Fertility of Soils 2007, 43,19. Abdullah, H. and Wu, H. Energy & Fuels 2009, 23,20. Cheng, C.-H and Lehmann, J. Chemosphere 2009, 75,21. Spokas et al. Chemosphere 2009, 77,22. Steiner et al. J. Environ. Qual. 2009, 39,23. Busscher et al. Soil Science 2010, 175,24. Brewer et al. Environmental Progress & Sustainable Energy 2009, 28,25. Novak et al. Annals of Environmental Science 2009, 3,26. Novak, J. M. and Reicosky, D. C. Annals of Environmental Science 2009, 3,27. Singh et al. J. Environ. Qual. 2010, 39,A algaeG grassL hullM manureN nutshellP pomaceW woodChallengesn= 85
13Change in ash content as a function of pyrolysis temperature of biochar Change in ash content as a function of pyrolysis temperature of biochar derived from hard and softwoodWood material has lower ash contentGreater ash content in hard wood compared to softwood
14Change in the C/N ratio as a function of pyrolysis temperature of biochar Change in the C/N ratio as a function of pyrolysis temperature of biochar derived from hard and softwood.
15Change in the surface area as a function of pyrolysis temperature of biochar Change in surface area as a function of pyrolysis temperature of biochar derived from hard and softwood
16Box plots showing differences in a) ash content and b) C/N ratios, but not in c) surface area across the different feedstocks. The grey boxes show the range from first to third quartiles, with the median dividing the interquartile range, into two boxes for the second and third quartiles. Letters show significant differences (p<0.05) according to a one-way ANOVA followed by Tukey (HSD) multiple means comparison
17Suggested guidelines Property Agroecosystem consideration Ash content Hydrophobicity and retention of agrochemicalsC/N ratioInitial Immobilization of soil NSurface areaSorption of pesticides, herbicides and heavy metals, sites for fungal and microbial colonizationCharacteristicSuggested guidelineAsh contentgrass ≈ manure >> nut shells, pomace and wood(hard wood > soft wood)C/N ratiowood >> grass> pomace> manure(soft wood > hard wood)Surface areatemperature dependent
18Acknowledgements Xiaoming Zhang Lucas C.R. Silva Johan Six Sanjai J. ParikhUC Davis Agricultural Sustainability Institute (ASI) Junior Faculty AwardDavid and Lucile Packard Foundation
19Effects of biochar Improves However many other studies have shown water holding capacitynutrient retentionsoil fertilityagricultural yieldgreenhouse emission (GHG) mitigationHowever many other studies have shownno increase in crop yields,increased GHG emissions,unintended “liming” of soils.Results often linked to the properties of the biochar used, application rate, soil type and climate.