Matching Biochar Characteristics with Metals- C Contaminated Soil to Effectively Reduce Metal i d S il Eff i l R d M l Bioavailability at Mining Sites Mark G. Johnson Research Soil Scientist Research Soil Scientist Clu-In Seminar November 7, 2017
Outline of Presentation • What is biochar? • How is biochar made? • Biochar properties Biochar properties • Biochar and metal sorption • Why EPA and biochar? • Biochar as an amendment for metal Bi h d t f t l contaminated spoil soils • Tuning biochar properties to address spoil soil limitations limitations • Insuring a good match between site conditions and soil amendments • Field Studies Field Studies • Target soils • Monitoring site conditions • Summary Summary • Outlook for the future 2
What is Biochar? • Carbon-rich solid produced by heating biomass in the by heating biomass in the absence of oxygen (pyrolysis) • Residual product of bio- p energy production Biochar from Wood Chips • Porous solid with a number of beneficial properties • Properties depend upon f feedstock, pyrolysis d k l conditions and possibly other modifications modifications Biochar from Wood Pellets 3
What is Biochar? Ponderosa Pine Biochar Ponderosa Pine Biochar Poultry Litter Biochar Poultry Litter Biochar 4
Charcoal being added to Willamette Valley soil following a grass field fire 6
Making Biochar via Pyrolysis: Energy Extraction from Biomass Energy Extraction from Biomass Concept diagram of low-temperature (350 to 500 °C) pyrolysis based bio-energy production with biochar storage in soil. Typically, between 20 and 50% of the initial biomass carbon is converted into biochar and can be returned to soil (Lehmann, 2007). 7
Comparison of Pyrolysis Processes for Syngas (Energy) and Biochar Production (Energy) and Biochar Production http://www.csiro.au/files/files/poei.pdf 8
Pyrolyzers: Heating Biomass Without Oxygen Old School Highly Controlled Lab-Scale Industrial Portable 9 Slide - D. Crowley
Modern Slow Pyrolysis Unit: Prineville, OR Beehive, Teepee or Wigwam Burner – Historically used to burn sawmill wastes 10
Pyrolysis Retort Feedstock Hopper Biochar Product 11
Examples of Biochar Feedstocks Switchgrass Switchgrass Pine Chips Pine Chips Swine Solids Swine Solids Poultry Litter Poultry Litter 12
Energy Extraction and Biochar Production Wood Chip Wood Chip Retort Auger Saw Mill Waste Coarse Wood Chips Wood Chips Feed Into Gasification Retort Coarse Fine Biochar Biochar Bi h Retort Volatile Boiler Gases Hot Water From Boiler Heats “Waste Product” = High Volatile Gases From 5 Acres of Greenhouses Quality Biochar Retort Feed Into Boiler 13
Biochar has a Range of Structural Properties that Depend Upon Pyrolysis Temperature and Conditions Depend Upon Pyrolysis Temperature and Conditions (Keiluweit et al, 2010) 14
Adsorption, Leaching, and Distribution of Simazine in Soils Amended with Biochar Control Control 15 D.L. Jones et al. / Soil Biology & Biochemistry 43 (2011) 804-813
Weed control of barnyard grass with Diuron herbicide applied at different concentrations to soil amended with varying y g concentrations of wheat straw biochar. (Yang 2006) 16
Key Biochar Properties Key Biochar Properties • pH • Ash content • Ash content • Proximate carbon • Volatile matter • Fixed carbon i d b • Surface area • Porosity Porosity • Pore size distribution • Chemistry • Total elemental • Total elemental • Nutrients • Cation exchange capacity (CEC) 17
SEM Images of Douglas-fir Wood Chip Feedstock and Biochar Raw Feedstock 300 °C 400 °C 500 °C 600 °C 700 °C 18
Proximate Carbon Analysis Procedure • Quantify three constituents of biochar Adapted from ASTM Method D1762-84: Chemical Analysis of Wood Charcoa l • Volatile matter l il Weigh Dry Biochar into Inconel Crucibles (A) • Low molecular weight carbon • Labile carbon fraction Heat Biochar in Covered • Fixed carbon Fi d b Crucibles at 950°C for 6 minutes. • Stable forms of carbon • Biopolymer (lignin, cellulose, Reweigh when cool. (B) hemicellulose etc ) hemicellulose, etc.) • High degree of aromaticity Heat Biochar in Uncovered Crucibles at • Ash content 750°C for 6 hours. • Residual mineral matter • Residual mineral matter Reweigh when cool. (C) Volatile matter = B – A; Fixed carbon = B – C; Ash content = C 19
Arundo donax - 300 C° Arundo donax - 500 C° † Ternary Plot of Proximate Carbon Fractions Arundo donax - 700 C° Formosa Mine Extract Study - Summer 2014 Anaerobically Digested Fiber - 300 C° Anaerobically Digested Fiber - 500 C° Anaerobically Digested Fiber 500 C Anaerobically Digested Fiber - 700 C° ARS Char #1 ARS Char #2 0 100 ARS Char #3 ARS Char #4 10 90 90 ARS Char #5 ARS Char #5 ARS Kentucky Bluegrass Seed Screenings 20 80 ARS Rice Seed Screenings ARS Tall Fescue Seed Screenings % 30 n ARS Wood 70 o A b Douglas fir - 300 C° s s r r 40 40 h h a Douglas fir - 500 C° 60 C C Douglas fir - 700 C° o d 50 n e Dairy Manure Biochar (Enchar) 50 t x e i Elymus - 300 C° F n t Elymus - 500 C° 60 % 40 Elymus - 700 C° y Granulated Activated Charcoal 70 30 Hazelnut Shells - 300 C° 700 °C Hazelnut Shells - 500 C° 80 300 °C 20 Hazelnut Shells - 700 C° Miscanthus - 300 C° 90 10 10 Miscanthus Miscanthus - 500 C 500 C° Miscanthus - 700 C° 100 Oregon White Oak - 300 C° 0 0 10 20 30 40 50 60 70 80 90 100 Oregon White Oak - 500 C° Oregon White Oak - 700 C° % Volatile Matter 500 °C Spent Brewer's Grain - 300 C° Spent Brewer's Grain - 500 C° Spent Brewer's Grain - 700 C° Sorghum - 300 C° Sorghum - 500 C° † ASTM Method D-1762 20 Sorghum - 700 C°
Physical Properties of Biochar from y p Grass † vs. Wood Wood ‡ Different Feedstocks: Grass Carbon Volatile Volatile Fixed Fixed Surface Surface Pyrolysis Carbon Yield Yield Ash* Ash* Temperature Content Content Matter Matter Carbon Carbon Area Area (wt%) (wt%) (wt%) (wt%) (°C) (wt%) (wt%) (wt%) (wt%) (wt%) (wt%) (m 2 g -1 ) (m 2 g -1 ) 100 99.9 99.8 48.6 50.6 69.6 77.1 23.5 21.7 6.9 1.2 1.8 1.6 200 96.9 95.9 47.2 50.9 70.7 77.1 23.6 21.4 5.7 1.5 3.3 2.3 300 75.8 62.2 59.7 54.8 54.4 70.3 36.2 28.2 9.4 1.5 4.5 3.0 400 37.2 35.3 77.3 74.1 26.8 36.4 56.9 62.2 16.3 1.4 8.7 28.7 500 31.4 28.4 82.2 81.9 20.3 25.2 64.3 72.7 15.4 2.1 50 196 600 29.8 23.9 89.0 89.0 13.5 11.1 67.6 85.2 18.9 3.7 75 392 700 700 28.8 28 8 22 0 22.0 94 2 94.2 92 3 92.3 9.1 9 1 6 3 6.3 71 6 71.6 92 0 92.0 19.3 19 3 1.7 1 7 139 139 347 347 † Tall Fescue, Tall Fescue, ‡ Ponderosa pine Ponderosa pine *Ash = Metal and non-metal oxides, chlorides, phosphates, and carbonate residue (From Keiluweit et al, 2010) 21
Physical Properties and pH of Douglas-fir Biochar: A Function of Pyrolysis Conditions and Feedstock A Function of Pyrolysis Conditions and Feedstock Property 300 °C 400 °C 500 °C 600 °C 700 °C Production Yield 49.9 36.6 31.3 28.8 27.2 (%) Volatile Matter Volatile Matter 46.90 32.35 20.54 11.80 7.96 (%) 52.70 67.16 78.87 87.51 89.12 Fixed C (%) 0.40 0.48 0.59 0.69 2.93 Ash Content (%) Surface Area 3.7 3 7 13 7 13.7 353 6 353.6 391 3 391.3 379.9 379 9 (m 2 g -1 ) 4.67 5.95 6.68 7.48 8.22 pH 22
Fourier Transformed Infrared (FTIR) Spectra of Douglas-fir Biochar and Feedstock Fourier Transformed Infrared (FTIR) Spectra of Douglas fir Biochar and Feedstock Aliphatic C-Hs O-H 700°C C=O C=C C=C C-O C-O 600°C C-O from Polysaccharides bance 500°C Aromatic C-Hs lative Absorb 400°C Rel 300°C Feedstock Transmission FTIR: 0.5 % material in pressed KBr pellet 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 Wavenumbers (cm -1 ) Wavenumbers (cm ) 23
Early Research: First Study Mine spoil “soil” from Leadville, CO • Simulated Rainwater (SRW) extraction Si l d i (S ) i (pH 4.5) • 25 mls of filtered SRW added to 0.25 g of Douglas-fir biochar • 24 hour contact time • Biochar separated from SRW solution Biochar separated from SRW solution • Characterization of SRW solution with ICP AES ICP-AES 24
% Change in Initial Metal Concentration of Simulated Rainwater Extract of Leadville, CO Mine Spoil after 24 Hour Contact with Extract of Leadville CO Mine Spoil after 24 Hour Contact with Douglas-fir Biochar Initial Metal Metal 300 °C 400°C 500°C 600°C 700°C Concentration (mg kg -1 biochar) Al 247 3.8 21.8 68.2 92.9 98.6 Ca 57922 -0.4 -0.8 -1.0 -2.4 -2.6 Cd 101 3.7 3.9 5.0 5.3 6.4 Cu 204 8.4 17.5 65.1 87.1 97.4 Mg 8441 3.8 3.4 2.8 2.1 5.9 Mn Mn 2364 2364 4 5 4.5 4.2 4 2 3 7 3.7 3 2 3.2 7 4 7.4 Pb 198 11.2 21.1 54.8 72.5 95.3 Zn 8720 3.6 2.9 3.1 3.6 5.5 25
Early Research: Second Study Cu sorption on biochar • 25 mls of a 5 mM Cu(NO 3 ) 2 ·2.5 H 2 O solution added to 0.25 g of Douglas- fir biochar • 24 hour contact time • Biochar separated from Cu solution, washed with MeQ water and dried Q • Cu sorption characterized with X-Ray Absorption Spectroscopy Absorption Spectroscopy 26
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