Catalytic Properties of Biochar for Chemical Synthesis Jim Kastner, Joby Miller, Rick Ormsby (Biological and Ag. Engineering Dept.) Jason Locklin, Kristen Fries (Chemistry and FOE) and Down to Earth Energy, Monroe GA IBE 2010 Biofuels/Biomaterials Conference March 4-7 th, 2010 Cambridge, MA
Research Objectives Develop value added products from agricultural and forestry residues Develop catalysts from the thermochemical biorefinery Develop carbon supported catalysts Convert biomass (e.g., peanut hulls) into a functional carbon Attach catalytic functional groups to carbon surface Attach acid and basic functional groups Produce solid acid and base carbon supported catalysts
Research Rational Develop solid acid and base catalysts for liquid fuel and chemical synthesis (biodiesel production and lignocellulose hydrolysis) Recoverable and reusable Reduce/eliminate pollution Current catalysts (H 2 SO 4, sodium methoxide) end up as waste More stable, less expensive then current solid catalysts Made from renewable biomass Made from a thermochemical biorefinery
Models for Catalyst Formation from Biochar via Biomass Pyrolysis Hardwood Hemicellulose Sulfonation 99% H 2 SO 4, 20 ml/12.5 g char, mixed, decanted Heated at 100-250 o C, 12-18 h O OH S O Acidic Cellulose Lignin Pyrolysis 400-500 o C, N 2 Depolymerization Volatilization Cracking Dehydration Rearrangment O S O OH Formation of Sulfonate Groups on Aromatic Surface Structure of Char Toda et al., Nature 438, 10 (2005) 178 Synthesized via sulphonation with 96% H 2 SO 4 or fuming sulfuric for 15 h
Introduction Biodiesel Application
Solid Catalysts for Biodiesel Problems with Current Biodiesel Process Feedstock s too expensive, currently can t use high FFA feedstocks, competition with food Less expensive feedstocks contain high level of FFA s Waste Oils, Rendered Fats and Oils Possible conversion of free fatty acids (FFAs) to methylesters 1 fatty acid + 1 methanol 1 fatty acid methylester + 1 H 2 O Not possible with current liquid homogeneous catalytic systems Current catalysts (liquids) end up as waste Can t use cheaper feedstock s due to presence of FFA s Free fatty acids, such as palmitic or stearic acid FFA s create soap if used with base catalyst Solid acid and base catalysts, potential solution Recoverable and Reusable Can treat high FFA feedstock Eliminates waste Potential continuous process
Advantages of Solid Carbon Catalysts Stable under acidic and basic conditions Stable at high temperature (200-300 C) Active material (e.g., acidic functional groups) can be finely dispersed throughout the carbon structure Renewable carbon source can be used to generate the active carbon Use biochar generated from pyrolysis or thermochemical platform Non-polar nature of the support matrix may prevent adsorption of polar molecules (e.g., water or glycerol) that can deactivate the catalyst in transesterification/esterification of lipids Can have very high surface areas 500 to 1500 m 2 /g
Experimental Methods Biochar Generation and Functionalization
Solid Acid Catalyst from Biochar Biomass Sources Pelletized peanut hulls and pine, and pine chips Pyrolyzed in batch reactor 400, 500, and 600 C 2 C/min 30-40 min holding time at temperature set point Temperature (C) 700 600 500 400 300 200 100 0 Temperature Profile -Clean Pine Chips 400C Pyrolysis 0 60 120 180 240 300 360 420 480 540 600 Time (minutes) N2 Sweep Gas Tank Mass Flow Controller Biomass Pyrolysis Reaction Internal Reactor/External Furnace Biochars characterized ph, surface area, DRIFT, ATR, some SEM CHNS and elemental analysis Solids collected, acid/base functionalized (1) (2) (3) Permanent Gases CO, CO2, H2 Bio-oil Collection (4) Condensation Unit Three Condensers in Series in and Ice Bath
Solid Acid Catalyst from Biochar Acid Functionalization Sulfonation Concentrated sulfuric acid Pelleted biochar ground, screened 4-12 mesh 12.5 g treated with 20 ml, 99% H 2 SO 4 Heated in ceramic crucible in a muffle furnace 100, 150, and 250 C for 12 hours Cooled, washed with DI water until rinse constant ph, and dried overnight (110 C) Anticipated functional group: -C-SO 3 H
Solid Acid Catalyst from Biochar Acid Functionalization Ozone Treated 25 g biochar, room temp. 1 L/min, 33 mg/m 3 ozone, 6 hours Anticipated functional group carboxylic acid, -COOH (2) (3) Mawhinney and Yates, Carbon 39 (2001) 1167 1173 Oxygen (1) (4) Ozone Treatment 1 - pure oxygen input 2 - mass flow controller 3 - ozone generator 4 - packed bed column 5 - ozone detector 6 - exhaust (5) Tessonnier et al., Angew. Chem. Int. Ed. 2009, 48, 6543 6546 functionalizing CNT s with amines (6)
Solid Base Catalyst from Biochar Base Functionalization Similar Process to Acid Low temperature pyrolysis 500 C 2 C/min 30-40 min holding time at temperature set point Pretreated with Ozone or HNO 3 Adds carboxylic acid groups to surface Treat with a strong organic base Organic base attached to carboxylic acid groups» Ethylenediamine (EDA),» 4-aminophenoxide (4-AP) Heated, 65-110 C Holding time, 22 h 3 days EDA NH 2 H 2 N H N O - 2 Na + 4-AP Organic base decanted, catalyst washed with MeOH (8-10 X) Heated/dried at 100 C overnight
Solid Acid Catalyst Results Biochars (non-functionalized) Low surface area, 2-4 m 2 /g Variable ph, but basic DRIFT analysis Aromatic and aliphatic groups Acid functionalized biochars - DRIFT Analysis Ozone Treatment Non-polar structure eliminated Carboxylic acid groups formed Sulfonation A large peak at 1750 cm -1, indicative of a carboxylic acid group appeared in the sulfonated peanut hull chars generated at 400 and 500 C SO 3 H groups identified by DRIFT and ATR Acid density increased with decreasing pyrolysis temperature and sulfonation temperature
Results Biochar Characterization Solid Acid Esterification Tests
Solid Acid Catalyst Characterization Physical and chemical characteristics of biochar used to develop catalysts Materials Activated * Peanut Hull Char Peanut Char Pine Chip Char Pine Chip Char Properties Carbon (400 C) (500 C) (400 C) (500 C) (Lignite Coal) Generation Process Steam Pyrolysis-N 2 Pyrolysis-N 2 Pyrolysis-N 2 Pyrolysis-N 2 Reactor/Residence Time Unknown Batch/40min Batch/40min Batch/40min Batch/40min ph 4.6 10.5 10.1 7.55 8.3 Surface Area, m 2 g -1 506 ± 34 NM 3.2±0.6 3.8 ± 0.14 2.75 ± 0.2 O 3 treated, 30 min 494 ± 57 ND ND ND ND Pore Volume (ml g -1 ) 0.55 ± 0.005 NM 0.004± 3e -4 ND ND Selected Elements Mean Mean Mean Mean Mean (ppm or mg kg -1 ) Cu ND 16 18 25 9 Mn 116 157 274 258 Mo 4.8 < 1 < 1 < 1 Ni 2.3 3.95 < 2 < 2.91 Fe 1000 1094 150 50 Ca 4620 4,090 1710 1850 K 15,200 20,700 1450 1450 Mg 2,190 2,478 600 590 ND - Not Determined, NP- Not Performed, AC Activated Carbon, BDL Below detection limit of 2 ppm *, Measured by Down to Earth Energy
DRIFT Analysis PCC 400C, O 3 DRIFT analysis of pine chip char (PCC) chars generated at 400 C via pyrolysis, pre-oxidized with ozone. DRIFT analysis in the Kubelka- Munk mode, the signal ranged from 0-0.25 for the ozonated chars, and 0-6 for the nontreated chars (i.e., biochar). Biochar 1000-1500 and 3100-3500 cm -1, C-O, ethers C-H, aliphatics 1600 cm -1, C=C olefinic 2900 cm -1, C-H aromatic PCC 400C Ozonated Biochar 1750 cm -1,C=O 500 1000 1500 2000 2500 3000 3500 Wavelength, cm -1
DRIFT Analysis ATR Analysis Sulfonated Biochar 500C PHC, 250C Sulfonation 1750 cm -1,C=O 600 cm -1,C-S 1040 cm -1,SO 3 1200 cm -1,S=O 1377 cm -1, O=S=O 500C PPC, 250C Sulfonation PCC 400C, 100S 400C PCC, 100C Sulfonation PCC 400C - Control 500 1000 1500 2000 2500 3000 3500 Wavelength, cm -1 1000 1500 2000 2500 3000 3500 Wavelength, cm -1
Sulfur Analysis of Functionalized Biochar Catalysts Carbon, % Nitrogen,% Sulfur, % SO 3 H Density mmol/g a PHC-500P 64 ± 1.7 2.0 ± 0.30 0.14 ± 0.05 PCC-400P 65 ± 0.38 1.8 ± 0.6 0.10 ± 0.03 PCC-400P-100S 56 ± 0.30 0.24 ± 0.01 3.7 ± 0.08 1.12 ± 0.02 PPC-400P-100S 62 ± 0.76 0.40 ± 0.08 1.2 ± 0.11 0.34 ± 0.01 PCC-400P-100S 58 ± 0.23 0.39 ± 0.13 2.30 ± 0.08 0.69 ± 0.006 PCC-400P-150S 46 ± 17.4 0.31 ± 0.03 1.39 ± 0.35 0.41 ± 0.08 PCC-400P-250S 62 ± 20.5 0.43 ± 0.23 0.86 ± 0.30 0.24 ± 0.06 PHC, Peanut Hull Char; PCC, Pine Chip Char; PPC, pine pellet char P, Pyrolysis Temperature; S, Sulfonation Temperature a, calculated from sulfur content assuming all S atoms are in the SO 3 H form with baseline sulfur content subtracted
Catalytic Testing/Screening Esterification of Palmitic and Stearic Acid Small scale batch reactor system (Reacti-Therm, Pierce Thermo Scientific) Used for Screening Catalysts Known amount of catalyst, typically 0.2 g used 5 ml total volume Known initial mass of palmitic (C 16 -saturated FFA) or stearic (C 18 -saturated, both at 200-500 ppm) and methanol (4 ml). Mixture was then heated at 55-60 C and sub-samples taken as function of time to determine the formation of methylesters via GC analysis Control reactions consisted of the untreated char (negative control) or use of HCl (positive control)
Catalytic Testing Fractional removal of palmitic or stearic acid measured Based on the defined initial concentrations of the FFA's Maximum theoretical amount of methylester that could form, and the concentration of the methylesters of the FFA's that formed during the catalytic reaction Measured by GC/FID or GC/MS
Catalytic Testing All sulfonated chars catalytically active for esterification of palmitic and stearic acid with methanol Chars treated with ozone only were not active (too weak an acid) Sulfonated biochars - typically complete ( 90-100% conversion) within 30-60 minutes at 55-60 C Of the synthesized catalysts, 400 C pyrolyzed pine chip char, sulfonated at 100 C, resulted in the highest reaction rate and lowest reduction in conversion (or deactivation) when reused multiple times Catalytic activity declined with reuse (without regeneration) Heating catalyst at 125 C allowed reuse without catalytic decay (95-100% conversion up to 7 times) Demonstrated esterification of FFA s (11-14%) spiked in poultry fat 70-90% conversion in 2 h at 65 C
1.2 Palmatic Acid Esterification, Pine Pellet Biochar Catalytic Testing 1.2 Palmatic Acid Esterification, Pine Pellet Biochar 1.0 1.0 Fractional Conversion 0.8 0.6 0.4 0.2 Ozonated and Sulfonated Sulfonated Ozonated Only Untreated Biochar Fractional Conversion 0.8 0.6 0.4 0.2 Ozonated and Sulfonated Sulfonated Ozonated Only Untreated Biochar 0.0 0.0 0 20 40 60 Time, min 0 20 40 60 Time, min Palmitic Acid Esterification, Peanut Hull Biochar Stearic Acid Esterification, Peanut Hull Biochar 1.2 1.2 1.0 1.0 Fractional Conversion 0.8 0.6 0.4 0.2 Ozonated and Sulfonated Sulfonated Ozonated Only Untreated Biochar Fractional Conversion 0.8 0.6 0.4 0.2 Ozonated and Sulfonated Sulfonated Ozonated Only Untreated Biochar 0.0 0.0 0 20 40 60 Time, min 0 20 40 60 Time, min Comparison of esterification catalytic activity between sulfonated pelletized peanut hull and pine biochar (500 C pyrolysis, sulfonation 250 C). Reactions conditions were 200 ppm palmitic or stearic acid in methanol (5 ml), 0.20 g char, and 58 C.
Catalytic Testing Comparison of esterification catalytic activity between different sulfonated biochars. Reactions conditions were 500 ppm palmitic and stearic acid, 0.50 g char, and 58 C for 1 hour. Catalysts were recovered, rinsed with methanol and reused without further treatment. 400C-P, is 400 C pyrolysis 100C-S, is 100 C sulfonation temperature
Catalytic Testing - Reuse Theory water adsorption inhibiting catalyst Tested heating recovered solid acid catalyst for reuse Effect of heating the acid catalyst in heptane (left, 250 C) or heating only (right, 125 C) on esterification activity during reuse. The period before A indicates methanol rinsing only, after A indicates heptane rinsing following by heating at 250 C, and after B represents heptane rinsing followed by heating 125 C (left). The catalyst was generated from pine chip biochar pyrolyzed at 400 C and sulfonated at 100 C for 12 h. All reactions were performed at 60 C with0.5gof sulfonated char for 30 minutes. Note Regeneration treatment was not performed on reuse of the char catalyst from treatments 1 to 7 (top, left).
Catalytic Testing Poultry Fat Larger scale batch reactors 50 ml volume Collected local rendered poultry fat Spiked with palmitic and stearic acid 11.5% FFA s 36 g fat, 2.2 g palmitic, 2 g stearic 33 ml of methanol 2g of acid functionalized biochar used Used best char from previous studies Pine chip char - Pyrolysis at 400 C, sulfonation at 100 C Heat at 65 C for 2 hour Measured FFA s at end 70-99% conversion of FFA s in Poultry Fat (triplicate)
Catalytic Esterification Comparison to Literature Free fatty acid conversions (palmitic and stearic acids) to methyl esters in rendered poultry fat and soybean oil using a solid acid carbon catalyst (400 C pine chip biochar, sulfonated 100 C) and comparison with literature (65 C, 2 h, 2.0 grams of biochar catalyst). Catalyst Fat or Oil MeOH:FFA % FFA s % Catalyst % Conversion Residence Time, Conversion Molar Ratio (w/w) (w/w) Temp. Measurement (h, C) Method PCC-400P-100S Poultry Fat 39:1 13.9 5.6 49 ±7 2, 65 GC/FID 98 ±0.03 2, 65 TAN* 55:1 10.5 3 81 ±16 2, 65 GC/FID 101.6 ±0.02 2, 65 TAN* Soybean Oil 39:1 13.5 5.6 53 ±6.5 2, 65 GC/FID Pyrolyzed-Starch a Waste Oil 20:1 27.8 10 60 2, 80 GC/FID Amberlyst BD20 b Trap Grease 6:1 50 20 62 2, 80 TAN Pyrolyzed-Glucose c Palmitic-Soybean Oil 6:1 10 2 20 1, 60 1 H-NMR, Acid Titration Dowex 550A d Oleic- Sunflower 6:1 10.7 2.3 80-90 2, 55 Acid Titration *, Conversion to methyl esters based on measurement of free fatty acids using potentiometric titration (ASTM 664), TAN is total acid number a, Lou et al., 2008 % conversion for esterification of FFA s and transesterification of triglycerides b, Park et al., 2010 c, Mo et al., 2008 - solid acid, carbon catalyst via glucose impregnation of Amberlite XAD1180, followed by pyrolysis and sulfonation d, Marchetti et al., 2007 ethanol used in esterification
Results Biochar Characterization Solid Base Transesterification Tests
Solid Base Catalysts Base Functionalization Similar Process to Acid Low temperature pyrolysis Used pine and peanut hull pellets 500 C 2 C/min 30-40 min holding time at temperature set point Pretreated with Ozone or HNO 3 Adds carboxylic acid groups to surface 2 Different strong organic bases attached Total of six solid base catalysts generated 2 Biochars - peanut hull and pine pellets 2 pretreatments - HNO 3 treated (minus pine pellets), Ozone treated 2 organic bases or EDA and 4-aminophenoxide
Solid Base Catalyst Characterization DRIFT Analysis O 3 and HNO 3 treatment generated COOH, 1750 cm -1 Reaction with organic bases indicated amide bond formation Band at 1750 cm -1 shifted to 1600-1650 cm -1
Pine Chip Biochar DRIFT Analysis EDA Functional Biochar 1750 cm -1,C=O 1650 cm -1, C=O in amide Peanut Hull Biochar DRIFT Analysis PCC 400C, O 3, EDA PHC 500C, HNO3, EDA PCC 400C, O3 PHC 500C,HNO3 PCC 400C PHC 400C 500 1000 1500 2000 2500 3000 3500 Wavelength, cm -1 500 1000 1500 2000 2500 3000 3500 Wavelength, cm -1
Solid Base Catalytic Testing/Screening Transesterification of glyceryl tridodecanaote Small Batch Reactors 0.5 g catalyst, 2 ml 500 ppm each of n-hexadecane and methyl pentadecanoate internal standards, and glyceryl tridodecanoate in anhydrous methanol Agitation at 300 rpm, 65 C, 3 h + 3 methanol (base catalyst) Quench reaction and sample for GC/FID or GC/MS to quantify dodecanoate methylesters Base functionalized chars resulted in 30-100% conversion of glyceryl tridodecanoate and formation of methylesters 3 +
Solid Base Catalytic Screening Transesterification of glyceryl tridodecanaote Biochar Pretreatment Base ph %Conversion Peanut Hull HNO 3 4-AP 9.56 100 Peanut Hull Ozone 4-AP 9.63 100 Peanut Hull HNO 3 EDA 10.32 30 Peanut Hull Ozone EDA 11.15 100
Solid Base Catalytic Screening Transesterification of glyceryl tridodecanaote Biochar Pretreatment Base ph %Conversion Pine Pellets Ozone 4-AP 9.50 79 Pine Pellets Ozone EDA 10.49 100
Solid Base Catalytic Testing Selected Base Functional Peanut Hull Biochar Transesterification of soybean oil Catalysts Tested Peanut hull biochar, ozone, EDA Peanut hull biochar, ozone, 4-AP Batch Reactor System 8 g of catalyst 41 g of soybean oil, 41 g of methanol Stirred at 65 C, 3 h Reaction mixture filtered, 2 phases Bottom layer, biodiesel, collected Analyzed by GC/FID - ASTM Method D6584-07 Potentiometric titration for total acids using ASTM Method 664-07 Closed cup flash point using ASTM Method D93-07
Solid Base Catalytic Testing Transesterification of soybean oil Compared to Sodium Methoxide catalyst (traditional method) Complete conversion of soybean oil to biodiesel using peanut hull, ozone pretreated, 4-AP attached catalyst Low to no measureable conversion using EDA catalyst Results comparable to sodium methoxide catalyst A B C Samples of soybean oil (A), biodiesel from 4 AP biochar catalyst (B), and biodiesel from sodium methoxide conventional methodology (C).
Solid Base Catalytic Testing GC/FID Results Soybean Oil Diglyceride and Triglycerides Solid Base 4AP, Catalyst Sodium Methoxide Catalyst C16, C18 methylesters or biodiesel C16, C18 methylesters or biodiesel
Catalytic Transesterification Comparison to Literature Catalytic activity of ozone oxidized biochar, functionalized with EDA and 4-aminophenoxide, as base catalysts for transesterification of triglycerides in soybean oil (except where noted) at 65 C for 3 hours using 8.5 grams of biochar catalyst and comparison with literature. Base Catalysts MeOH:Oil T % Catalyst % Conversion Catalyst Conversion Molar Ratio C (w/w) (Time, h) Treatment/Symbol Measurement Method EDA 8.5:1 65 8.9 0.0 (3) PHC-O-EDA-400-B GC/FID 4-AP 39:1 65 8.9 100 (3) PHC-O-4AP-500 GC/FID Na-Methoxide? 65? 100 (3) GC/FID CaO a 12:1 65 8 95 (3) 2 % water GC/FID CaO b 27:1 25? 99 (24) Nanocrystalline 1 H NMR Ca(OH 3 ) c 2 2:1 65 4 95 (2) GC/FID Aminated Carbon 12:1 60? 65 (3) or Nanotubes or CNT d 77 (8) Triethylamine attached CNT? *, conversion to methyl esters based on measurement of free fatty acids using potentiometric titration a, Liu et al., 2008 b, Reddy et al., 2006 c, Liu et al., 2008b d, Villa et al., 2009, substrate used was glyceryl tributyrate
Lignocellulose Hydrolysis Using Solid Acid Catalysts Biochemical Refinery Application
Cellulosic Ethanol Application Key Concept Replace Enzymes with Solid Acid Carbon Catalyst Hydrolyze cellulose and hemicellulose to sugars (e.g., glucose and xylose), then ferment or catalytically convert to liquid fuels (e.g., ethanol or isobutanol) or chemicals (lactic acid, HMF) Enzymes are expensive, currently unrecoverable, and sensitive to inhibitors Limited environmental conditions Near neutral ph Temperature typically < 40-50 C Enzymes sometimes have a much lower reaction rate compared to chemical catalysts
Cellulosic Ethanol Application Solid Acid Carbon Catalysts Generation Same method, only difference, Biochar generated from pyrolysis crushed to a fine powder before sulfonation to generate acid catalyst Biomass: Peanut Hulls Pellets, Pine Chips Pyrolysis at 400 C Sulfonated at 100 C, 12 h (99% H 2 SO 4 )
Catalytic Testing Lignocellulose Hydrolysis Small batch reactors 25 ml Pyrex Erlenmeyer flasks, bottles or 10 ml high pressure tubes Model Compounds Used: Cellobiose for cellulose, Xylan (birch wood and locust bean gum) for Hemicellulose 10 g/l Cellobiose, 1 and 10 g/l Xylan 30, 60, 90, and 120 C at various residence times Reactions performed at 30, 60 and 90 C performed in a shaker/water bath under agitation Reactions at 120 C were performed in an autoclave without agitation Subsequently moved to a reactor/stirrer/hot plate with high pressure tubes Cellobiose, glucose, and xylose measured using HPLC with RI detector and standards
Cellulosic Ethanol Application Catalytic Results - Cellobiose Significant activity not measured until 90 C Effect of temperature on the hydrolysis of cellobiose (10 g/l, 1 g catalyst) using sulfonated pine biochar.
Cellulosic Ethanol Application Catalytic Results - Cellobiose Solid acid catalyst generated from pine chips appeared to have the highest activity Thermal hydrolysis did not occur (top figure) Unknown compound did form in the catalytic systems attributed to a leachate from the biochar, since this same unknown appeared in reactors with the sulfonated biochar only (not shown)
Cellulosic Ethanol Application Catalytic Results - Cellobiose Catalysts used at 120 C were recovered (by filtration, but not washed) and reused The reused solid acid catalysts were active for cellobiose hydrolysis decline in fractional conversion, most notably for the peanut hull biochar Catalytic hydrolysis of cellobiose (10 g/l, 10 ml working volume) using solid acid catalysts (1 g biochar) at 120 C. X is the fractional conversion of cellobiose and Y is the glucose yield. Catalysts Peanut Hull Biochar Pine Chip Biochar Time, hrs X Y, g/g X Y, g/g 0 0 0 0 0 3 0.64 ± 0.02 0.66 ± 0.024 0.93 ± 0.084 1.0 ± 0.094 3 (Recovered/Reused) 0.12 ± 0.08 0.45 ± 0.023 * 0.85 ± 0.13 0.83 ± 0.3 *carryover from solid catalyst
Chemical Synthesis Catalytic Results for Control Char Non-sulfonated biochar used as control Did not anticipate a reaction Cellobiose apparently hydrolyzed Unknown products produced Base peanut hull char has ph of 10.7 compared to 7.8 for pine chip char Suggests the possibility of chemical synthesis using solid base carbon catalyst Lactic acid from glucose Glucose to fructose HPLC chromatograms of control reactions, pine chip biochar with cellobiose (top) and untreated peanut hull biochar (bottom).
Chemical Synthesis Apparent Isomerization Activity for Base Char Glucose Fructose Glucose or Fructose Added, 10g/L 1 g char, 120 o C, 5 h Formed equilibrium mixture of glucose and fructose More recent data indicate conversion complete (equilibrium reached) within 1 h or less (potentially faster) R I S i g n a l R I S i g n a l 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 16000 14000 12000 10000 8000 6000 4000 2000 0 0 Peanut Hull Char Glucose 10 g/l - 120C 5 h Glucose 0 2 4 6 8 10 12 14 16 18 20 Time, min Fructose Unknowns Peanut Hull Char Fructose 10g/L 120C 5h Glucose 0 2 4 6 8 10 12 14 16 18 20 Time, min Fructose Unknowns
Hardwood Hemicellulose Hydrolysis 2000 Xylan Control 120C, 5 hr (1 g/l) Birch wood xylan used as model Solid Acid Catalysts (1 g) used at 120 C After 5 hours Xylose formed Xylan solution (1 g/l) turned from cloudy/brown to light clear brown Pine chip biochar catalyst: 60% conversion of xylan Peanut hull biochar catalyst: 40% of conversion xylan Based on assumption that 1 g/l of xylan forms 1 g/l of xylose and HPLC analysis for xylose RI Signal RI Signal RI Signal 1500 Unknown 1000 500 0 0 2 4 6 8 10 12 14 16 18 20 Time, min 5000 PHC- Xylan 120 5 hr 4000 Unknown 3000 2000 Xylose 1000 0 0 2 4 6 8 10 12 14 16 18 20 Time, min 8000 Pine Char - Xylan 120 5 hr 6000 Unknown 4000 2000 Xylose 0 0 2 4 6 8 10 12 14 16 18 20 Time, min
Hardwood Hemicellulose Hydrolysis 25000 24 hr - Control - Xylan 10 g/l, 120 o C 10 g/l Xylan (birchwood) 1 g solid acid catalyst Sulfonated pine chip biochar Hardwood Hemicellulose Hydrolyis Using Solid Acid Catalyst - 120 o C, Trial 1 R I Signal 20000 15000 10000 5000 0 0 5 10 15 20 25 25000 1hr - PC 400 - Xylan 10 g/l, 120 o C 20000 7 6 R I Signal 15000 10000 Xylose Concentration (g/l) 5 4 3 2 1 0 0 5 10 15 20 25 30 R I Signal 5000 0 0 5 10 15 20 25 4 hr - PC 400 - Xylan 10 g/l, 120 o C 25000 20000 Xylose 15000 10000 5000 Time (hrs) 0 0 5 10 15 20 25 Time (min)
Softwood Hemicellulose Hydrolysis Model for softwood hemicellulose Galactomannan β-(1,4)-d-mannose units Every 4 units, 1 galactose side substituted 10 g/l xylan (locust bean gum) 1 g solid acid catalyst, 10 ml Sulfonated Pine Chip Biochar 120 C, 5 h Mannose Galactose R I Signal RI Signal R I Signal 35000 30000 25000 20000 15000 10000 5000 0 35000 30000 25000 20000 15000 10000 5000 0 35000 30000 25000 20000 15000 10000 5000 0 10 hr Control - LBG 10 g/l, 120 o C Trial 1 0 5 10 15 20 Time, min 2 hr - PC 400 - LBG 10 g/l, 120 o C Trial 1 0 5 10 15 20 Time (min) 4 hr - PC 400 - LBG 10 g/l, 120 o C Trial 1 0 5 10 15 20 Time (min)
Conclusions Demonstrated synthesis of solid acid and base carbon catalysts from biochar Demonstrated feasibility of solid carbon catalysts for biodiesel production Cellobiose and xylan hydrolysis using solid acid catalyst demonstrated Clear potential for use in forest biofinery Hemicellulose extraction before pulping and paper and forest product production New value added products from biorefinery developed Generated from agricultural and forestry residues Generated from renewable biomass resources Foundation for carbon catalysis and chemical/liquid fuels Methanol to dimethylether or DME (a diesel substitute) Glucose to lactic acid (biodegradable polymer or polylactic acid, PLA) Glucose and xylose to furfurals In-line catalytic esterification of bio-oil vapors to stabilize bio-oil
Future Work Optimize pyrolysis for catalyst synthesis More detailed characterization of biochar and formed catalysts Need better understanding of biochar structure before and after functionalization Correlate structure with pyrolysis conditions and catalytic testing Detailed studies on reuse, longevity, and kinetics of reactions needed Biodiesel synthesis Cellulose and Hemicellulose hydrolysis Couple with hot water treatment of biomass for cellulose hydrolysis More detailed studies on adding basic functional groups and resultant catalytic activity required Expand research on catalytic activity to other products DME, bio-oil stabilization, glucose and xylose to chemicals