Presentation is loading. Please wait.

Presentation is loading. Please wait.

Use of chemical and physical characteristics to investigate trends in biochar feedstocks Fungai Mukome, Xiaoming Zhang, Lucas C.R. Silva, Johan Six, and.

Similar presentations


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, and."— Presentation transcript:

1 Use of chemical and physical characteristics to investigate trends in biochar feedstocks Fungai Mukome, Xiaoming Zhang, Lucas C.R. Silva, Johan Six, and Sanjai J. Parikh University of California, Davis US Biochar Conference, Rohnert Park, CA July 2012

2 What is Biochar? Walnut shell Wood Wood chips Fly ash carbon-negative.us Corn stover Rice HusksManure Orange peels

3 All biochars are not created equal…. (McLaughlin et al. 2009) Differ on – pH – Surface area – Ash content – Water holding capacity All a function of pyrolysis temperature (highest treatment temperature-HTT), pyrolysis method, residence time and feedstock – Cation exchange capacity (CEC) – H/C ratio – C/N ratio

4 Objectives 1.To characterize physical and chemical properties of various biochars (mostly commercially available) 2.To determine if trends exist for biochar properties that can be related to feedstock material, which can serve to develop guidelines for biochar use.

5 Objectives 1 Physical properties: – Moisture content – Ash content – BET Surface area – Surface morphology Chemical properties: – Elemental content – H and C content – pH – Cation exchange capacity – Surface basicity and acidity – Surface functionality (ATR-FTIR and Raman) Twelve biochars were analyzed

6 CharSource Material Pyrolysis Temp (°C) Ash (wt %) BET Surface Area (m 2 /g) Type (Hysteresis) BC_ ATurkey litter a Ps. II (H3) BC_B b Walnut shell Ps. II (H4) BC_CInoculated materialunavailable c Ps. II (H4) BC_DSoft wood Ps. II (H4) BC_E Wood + Algal digestate Ps. II (H3) BC_FWood Ps. II (H4) BC_GWood Ps. II (H3) BC_HWood chips Ps. II (H3) BC_IWood chipsunavailable5164.1Ps. II (H4) BC_JWood chipsunavailable Ps. II (H4) BC_KWood chipsunavailable Ps. II (H4) BC_LWood chipsunavailable Ps. II (H4) a Ps.II = Pseudo Type II b Unknown, not willing to provide or proprietary c Not commercially available Physical properties Wood Non-wood

7 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_F 10µm 100µm60µm Type 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 Scanning Electron Microscopy analysis

8 Char C (wt %) N (wt %) H (wt %) O (wt %) PO 4 -P (wt %) K (wt %) S (ppm) Fe (ppm) pH w (1:2) CEC a cmol/kg Acidity (meq/g) Basicity (meq/g) BC_A BC_B b BC_C BC_D BC_E BC_F BC_G BC_H BC_I BC_J BC_K BC_L a CEC = Cation exchange capacity b Not commercially available Chemical properties Wood Non-wood

9 Aromatic Aliphatic/Functionalized C=O C=C C-H C-O, C-H C-O FTIR: Fourier Transform Infrared Spectroscopy Greater aromaticity in wood derived biochar

10 Char x Aromatic C-H (744cm -1 ) x Aliphatic ether (1029cm -1 ) x Aliphatic CH 3 (1417cm -1 ) x Aromatic C=C (1587cm -1 ) x Aromatic carbonyl (1690cm -1 ) BC_A BC_B BC_C BC_D BC_E BC_F BC_G BC_H BC_I BC_J BC_K BC_L x. Ratios of peak intensities relative to the aromatic C-H stretch at 870cm -1 common to all spectra

11 Char Aliphatic ether (1029cm -1 ) y Raman I d /I g BC_A BC_B BC_C BC_D BC_E BC_F BC_G BC_H10.83 BC_I BC_J BC_K BC_L y. Ratio of peak intensities of the Carbon D (1350cm - 1 ) and G (1690cm -1 ) bands in Raman spectra D band (aromatic) G band (aliphatic & olefinic) I D - sp 2 disordered C atoms in aromatic ring structures I G - sp 2 disordered C atoms in aliphatic and olefinic molecules Approximates sp 2 : sp 3 ratio in amorphous carbon

12 Objective 2 1. Sharma et al. Fuel 2004, 83, Keiluweit et al. Environmental Science & Technology 2010, 44, Zheng et al. Journal of Hazardous Materials 2010, 181, Cao, X. et al. Bioresource Technology 2010, 101, Özçimen et al. Renewable Energy 2010, 35, Jindarom et al. Chemical Engineering Journal 2007, 133, Chan et al. Soil Research 2008, 46, Azargohar et al. Applied Biochemistry and Biotechnology 2006, 131, Wu et al. Industrial & Engineering Chemistry Research 2009, 48, Toles et al. Bioresource Technology 2000, 71, Van Zwieten et al. Plant and Soil 2010, 327, Chen, B. and Chen, Z. Chemosphere 2009, 76, Major et al. Plant and Soil 2010, 333, Argudo, M. et al. Carbon 1998, 36, Hammes et al. Applied Geochemistry 2008, 23, Chun et al. Environmental Science & Technology 2004, 38, Mahinpey et al. Energy & Fuels 2009, 23, Rondon et al. Biology and Fertility of Soils 2007, 43, Abdullah, H. and Wu, H. Energy & Fuels 2009, 23, Cheng, C.-H and Lehmann, J. Chemosphere 2009, 75, Spokas et al. Chemosphere 2009, 77, Steiner et al. J. Environ. Qual. 2009, 39, Busscher et al. Soil Science 2010, 175, Brewer et al. Environmental Progress & Sustainable Energy 2009, 28, Novak et al. Annals of Environmental Science 2009, 3, Novak, J. M. and Reicosky, D. C. Annals of Environmental Science 2009, 3, Singh et al. J. Environ. Qual. 2010, 39, n= 85 van Krevelen diagram of a) selected biochar (from literature) and b) 12 study biochar (inset) A algae G grass L hull M manure N nutshell P pomace W wood

13 Change 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 softwood

14 Change in the C/N ratio as a function of pyrolysis temperature of biochar derived from hard and softwood. Change in the C/N ratio as a function of pyrolysis temperature of biochar

15 Change 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

16 Box 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

17 Suggested guidelines CharacteristicSuggested guideline Ash content grass ≈ manure >> nut shells, pomace and wood (hard wood > soft wood) C/N ratio wood >> grass> pomace> manure (soft wood > hard wood) Surface area temperature dependent (soft wood > hard wood) PropertyAgroecosystem consideration Ash contentHydrophobicity and retention of agrochemicals C/N ratioInitial Immobilization of soil N Surface area Sorption of pesticides, herbicides and heavy metals, sites for fungal and microbial colonization

18 Acknowledgements Xiaoming Zhang Lucas C.R. Silva Johan Six Sanjai J. Parikh UC Davis Agricultural Sustainability Institute (ASI) Junior Faculty Award David and Lucile Packard Foundation

19 Effects of biochar Improves – water holding capacity – nutrient retention – soil fertility – agricultural yield – greenhouse emission (GHG) mitigation However many other studies have shown – no 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.


Download ppt "Use of chemical and physical characteristics to investigate trends in biochar feedstocks Fungai Mukome, Xiaoming Zhang, Lucas C.R. Silva, Johan Six, and."

Similar presentations


Ads by Google