Potential use of alkaline hydrogen peroxide in biomass pretreatment - PowerPoint PPT Presentation

NAXOS 2018 6 th International Conference on Sustainable Solid Waste Management Potential use of alkaline hydrogen peroxide in biomass pretreatment and valorization – a review Presented by: Ho Mun Chun Supervisor: A/P Wu Ta Yeong Date: 14 th June 2018

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Reaction Mechanism 5. Recent Applications 6. Advantages & Limitations 7. Conclusion 8. References 9. Acknowledgement 2

1 Introduction Bio-refinery:  Process to convert to bio-based biomass products and energy  Biomass – Food crop / Energy crop / Agro- industry waste (World Resource Council, 2016) Waste Valorization – Any processes or activities that utilize or convert normally neglected waste to highly useful and value added products or energy sources. (Kabongo 2013) 3

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Reaction Mechanism 5. Recent Applications 6. Advantages & Limitations 7. Conclusion 8. References 9. Acknowledgement 4

2 Problem Statement Cellulose Lignocellulosic biomass waste : (38 - 50%) (15 - 25%) Hemicellulose  Hundreds billion tonnes produced annually (23 - 32%) Lignin  Usually neglected Other  Potential feedstock for waste valorization Challenge in Utilizing Lignocellulosic Biomass :  Recalcitrant nature  Lignin-carbohydrate complex  Physical and Chemical Resistant (Yang et al, 2015) 5

2 Problem Statement Existing Pretreatment Methods Alkaline Hydrogen Peroxide :  Extraordinary performance  Little sugar degradation  Mild conditions 6

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Recent Applications 5. Advantages & Limitations 6. Conclusion 7. References 8. Acknowledgement 7

3 Background Information Hydrogen Peroxide: Hydroperoxyl anion:  Pulping and Bleaching solvent  Intermediate products under  React with aliphatic part of lignin under alkaline condition  Carbonyl and ethylene oxidation normal circumstances  Expose phenolic ring and causes  Initiator for radicals forming macromolecular structure alteration under alkaline condition and elevated temperature Alkaline HOO - + H 2 O H 2 O 2 + HO - H 2 O 2 + HOO - - • + H 2 O HO• + O 2 - •): Hydroxyl radical (HO•) and Superoxide anion radical (O 2  Strong oxidants  Oxidization of lignin  Fragmentation of biomass  Destruction of ester, ether cross-links and cleavage of β -O-4 bonds  Hemicellulose solubilisation and cellulose depolymerisation 8

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Recent Applications 5. Advantages & Limitations 6. Conclusion 7. References 8. Acknowledgement 9

4 Recent Applications Alkaline Hydrogen Peroxide  Dependent on operational variables  Optimization required targeting different biomass or applications Pretreatment  Efficiency depend on the promotions of radicals Lignin Hemicellulose Cellulose 10

4 Recent Applications Key findings :  Catalyst is essential in Recent Application hardwood pretreatment Biomass Initial pretreatment References  Maximum lignin solubilisation Li et al. Cu II (bpy)-catalyzed alkaline Hybrid of 50.2% (2013) poplar hydrogen peroxide  Uncatalysed lignin solubilisation 36.6% Solid loading = 1:10 (w/v)  Disproportional reactions due to T = Ambient temperature highly ordered cell wall matrix Time = 48 h  Diffusible homogeneous catalyst pH = 11.5 provide alternative route to H 2 O 2 concentration = 10 g/L improve site-specific reactions Catalyst concentration = 5mM 11

4 Recent Applications Recent Application Key findings :  Increased lignin removal from Biomass Initial pretreatment References 37.5% to 40.3% Li et al. Jerusalem Ultrasonic assisted alkaline  Degree of polymerization (2016) hydrogen peroxide artichoke reduced Ultrasonic frequency = 40kHz  Significantly increase Ultrasonic power = 500 W crystallinity index from 45% to Solid loading = 1:20 (w/v) 62.5% T = 50 ° C  Improve accessibility of Time = 120 min carbohydrate NaOH concentration = 2% (w/v) H2O2 concentration = 5% (w/v) 12

4 Recent Applications Recent Application Key findings:  Delignification of 22% Biomass Initial pretreatment References  Glucomannan removal of 78% Alvarez- Douglas fir Alkaline hydrogen peroxide  Little degradation of cellulose Vasco and Zhang (2013) while removing protective barrier Solid loading = 1:10 (w/v) T = 180 ° C Time = 60 min pH = 11.6 H2O2 concentration = 4% (w/w) 13

4 Recent Applications Recent Application Key findings :  Reduced peroxide loadings to Biomass Initial pretreatment References 0.5% (w/v) Morone et al. Rice Straw Alkaline hydrogen peroxide-  Maximum lignin removal of (2017) assisted wet air oxidation 77.29%  Maximum cellulose recovery of Soaking in alkaline hydrogen peroxide 83.01% Time = 14 h  High temperature promote pH = 11.9 formation of carboxylic acids, eg. H2O2 concentration = 0.5 % Acetic acids (w/v)  pH drop to as low as 5.63 Pressurized with 6 bar air at 190 ° C for 20 min with mixing at 200 rpm 14

4 Recent Applications Recent Application Key findings:  Lignin removal of 80% Biomass Initial pretreatment References  Glucose yield of 90 % Mittal et al. Corn Alkaline hydrogen peroxide  Xylose yield of 80% (2017) stover  Lignin extraction depends on Solid loading: 1:10 (w/v) T = 50 ° C peroxide concentration Time = 3 h pH = 11.5 H2O2 concentration = 250 mg H2O2 / g dry biomass 15

4 Recent Applications (c) Surface Morphology Biomass after pretreatment  Noticeable change in colour  Reduced particle size  Disorder fibrils and formation (a) of tiny holes (d)  Cell disjoining with dimmer cell wall (b) (Mittal et al. 2017) (Morone et al. 2017) 16

4 Recent Applications Inhibitors Acetic acid – Yes. Degradation of acetyl group in removed hemicellulose. Total phenolic content – Yes. Inhibitor to fermenting strain. Furfural – None 5-hydroxymethylfurfural (HMF) – None 17

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Recent Applications 5. Advantages & Limitations 6. Conclusion 7. References 8. Acknowledgement 18

5 Advantages & Limitations Advantages:  Hydrolysate detoxification  Less cellulose degradation  Mild conditions  Highly fermentable pretreated biomass  Absent of furfural and hydroxymethylfurfural (HMF)  Environmentally benign chemicals  Availability Limitations:  High pH to deprotonate hydrogen peroxide  High peroxide loadings may affect economic viability  Required relatively long time at ambient conditions 19

Outline of Contents 1. Introduction 2. Problem Statement 3. Background Information 4. Recent Applications 5. Advantages & Limitations 6. Conclusion 7. References 8. Acknowledgement 20

6 Conclusion Conclusion Alkaline hydrogen peroxide pretreatment is compatible to subsequent bioconversion , safer decomposition products , and flexible in different process requirement, hence provide an alternative sustainable route to effective valorize biomass for biofuels or biochemical productions. Recommendation  Ambient temperature in effective biomass processing  Synergism of alkaline hydrogen peroxide in stage-wise pretreatment strategies  Recyclability of alkaline hydrogen peroxide 21