case annual meeting 2016 synthesis of cellulose
TRANSCRIPT
Synthesis of Cellulose Nanoparticles from Lignocellulosic Feedstock: A Roadmap
Kalavathy Rajan1,2, Angele Djioleu1,2, Elizabeth Martin1,3, and Jin-Woo Kim1,2
1Bio/Nano Technology Laboratory, Institute for Nanoscience & Engineering; 2Department of Biological & Agricultural Engineering; 3Arkansas Institute of Nanoscale Materials Science and
Engineering; University of Arkansas, Fayetteville, AR
ABSTRACT Cellulose, when deconstructed to nano-crystalline particles, finds a variety of applications from drug delivery to
material engineering owing to its unique physicochemical properties. Cellulose can be extracted from lignocellulosic biomass, an inexpensive and renewable feedstock, which contains cellulose in the ranges of 35 to 50%. There are different methods available for the production of cellulose nanoparticles from lignocellulosic biomass namely, I) biological delignification, II) chemical pulping, III) mechanical diminution, IV) dissolution and V) integrated synthesis and chemical modification. These methods are used to fractionate the lignocellulosic biomass and extract the cellulose fibers, which are then processed further to produce cellulose nano fibrils or cellulose nanocrystals. Each method has its own advantages and disadvantages and can be customized to fit the end user requirements. Lignocellulose is a complex polymer and it often necessitates combining two or more of the above-said fractionation techniques in order to improve the yield of cellulose nanoparticles. This presentation provides a road map for the deconstruction of lignocellulosic biomass to cellulose nanoparticles and a comparison of the feasibility and suitability of each of the production processes.
CASE Annual Meeting 2016
November 24–25, 2016 Little Rock, AR, USA
BACKGROUND & SIGNIFICANCE
Strategies to synthesize CNC from woody biomass will pave way for production of value added cellulosic co-products from forestry residues
DELIGNIFICATION STRATEGIES SUMMARY & CHALLENGES
The complex matrix of lignocellulose warrants a combined utilization of mechanical and chemical treatments and advanced fractionation techniques to obtain a suitable end product
MECHANICAL STRATEGIES
Center for Advanced Surface Engineering
Tunicates
Algae
Municipal solid waste
Woody biomass
Herbaceousbiomass
Cellulosic feedstock
Sources: NASS, USDA, 2012; Arkansas Energy Office, AEDC. http://arkansasenergy.org/energy-sources/biomass
14.1
2.8
2.7
0.24
0.14
0.11
0 5 10 15
Forestry residues
Municipal solid waste
Rice residues
Corn residues
Wheat residues
Cotton residues
Arkansas state renewable biomass sources (2013)
Million dry ton/ year
Lignocellulose is a renewable feedstock for the production of high-value cellulosic products like Cellulose Nano-Crystals (CNC). CNC has some unique properties such as, elastic modulus of 110-220 GPa similar to that of 302 stainless steel, tensile strength of 7500-7700 MPa, which is twice as much as that of Kevlar and density of 1.6 g/cm3, which is lighter than 302 stainless steel (Brinchi et al., 2013). CNC are rigid rod-like particles of variable dimensions; CNC from hardwood, for example, will have a dimension of 140-150 x 4-5 nm (Habibi et al., 2010). CNC are liquid crystalline and show birefringence (Moon et al., 2011). And since it is biodegradable and non-toxic, CNC find a variety of useful applications such as, “green” structural composites, rheology modifiers, barrier films, electro-optic devices, tissue scaffolds, contrast agents, etc. (Sinha et al., 2015).
Fig. 1A- Natural sources of cellulosic feedstock Fig. 1B- Renewable feedstock available in Arkansas for the production of value-added cellulosic co-products
Renewable sources of lignocellulosic feedstock grown in Arkansas are southern pine, hardwoods, rice and corn residues, etc. (Fig. 1B). Woody biomass are the largest sources of cellulosic feedstock and in Arkansas, the timber product output was reported to be 489 million cu. ft. (USDA Forestry service, 2009), which roughly translates to 60 million tons of cellulose per annum. There are a few studies on the production of CNC from bleached wood pulp and even fewer that focus on the production of CNC from woody feedstock. Conversion of woody biomass to CNC is a painstakingly long process and this study has strived to summarize the various production pathways.
Solid state fermentation of loblolly pine chips with white rot fungus (Trametes versicolor)
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Glucan
Xylan
Galacta
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Control 30 days
White rot fungi, like Trametes versicolor, are known to disrupt the surface lignin of woody biomass by virtue of secreting lignin-degrading enzymes like, polyphenol oxidases and lignin peroxidases. Thus it results in enriching the cellulose content of woody biomass by 18-20%. Pros: “Green” technology, consumes less energy and capital Cons: Time consuming, inconsistency in fungal growth
Biological delignification
Changes in loblolly pine chips composition after 30 days of incubation with Trametes versicolor fungi. Substrate carbohydrate concentration determined by HPLC analysis. Averages & standard deviation, n=3.
Chemical delignification Pulping process using caustic or acid sulfite reactions is commonly used in the paper industry for the extraction
of cellulose. Pulp yields are in the range of 80% of the theoretical maximum. During pulping the lignin molecules are depolymerized, chemically substituted and solubilized under acidic or alkaline conditions. After pulping, bleaching of wood pulp is required in order to remove the intractable lignin residues, if any, and bleaching agents such as, chlorine, oxygen, hydrogen peroxide, etc., are used under alkaline conditions. Pros: High purity. Cons: Time consuming, requires high chemical input and complicated downstream processing
EXPERIMENTAL SET-UP
CITED WORKS
2000 nm
A. TEM image of nanocellulose from cotton obtained by enzymatic hydrolysis and ultrasonication at 20 kHz. Bittencourt et al. 2008. https://www.hielscher.com/ultrasonic-production-of-nano-structured-cellulose.htm
B. TEM image of nanocellulose from hardwood obtained by high pressure homogenization at 30,000 psi using a microfluidizer. Tien et al. 2016, Carbohydrate Polymers 136, 485-492
C. TEM image of freeze dried Avicel®. Fortunati et al. 2012. Polymer degradation and stability, 97(10), 2027-2036 D. TEM image of ball-milled wheat straw cellulose. Nuruddin et al. J. Appl. Polym. Sci. DOI: 10.1002/APP.42990
• Brinchi et al.,2013. Carbohydrate polymers. 94(1):154-169 • Habibi et al., 2010. Chemical review. 110(6):3479-3500 • Moon et al., 2011. Chemical society reviews. 40:3941-3994 • Sinha et al., 2015. Journal of Biosystems Engineering. 40(4):373-393
A. Ultrasonication for dispersion of individual cellulose fibril B. Microfluidizer- It is a high pressure homogenization technique where the
cellulose fibrils are passed through a microfluidic pathway (30-50 µm) that creates high shear and facilitates fiber separation and size reduction.
C. Cryo-crushing- Uses lyophilization to enhance fiber fracture and size reduction.
D. Ball-milling- Fractures the cellulose fibers at the amorphous regions. Increases mechanical strength and promotes fibrillation.
E. Mechanical pulping- Fractionation of cellulose from woody biomass using heat and mechanical energy. Uses stone grinding mills and disc refiner plates. Pros: High yield. Cons: High energy input, low grade pulp
Strong acids like concentrated sulfuric and hydrochloric acid under controlled conditions can dissolve the amorphous cellulose and hemicellulose, to yield crystalline cellulose fibers. Milder acids like formic, acetic, peracetic and performic acids can be used to fractionate hemicellulose and acid soluble lignin regions. Enzymes like endo- and exo- cellulases and xylanases can be used to hydrolyze the amorphous cellulose and hemicelluloses.
Lignocellulose or Cellulose fiber
Acid hydrolysis
CNCEnzymatic hydrolysis
Solvent extraction
Ionic liquids
Chemical diminution
Dissolution Chemicals can be used to dissolve and fractionate either lignin (ethanol, methanol) or the carbohydrates (1-
ethyl-3-methylimidazolium acetate, N,N- dimethylacetamide, dimethylsulfoxide, persulfate) from woody biomass. Pros: Less energy consumption. Cons: Requires advanced fractionation and additional purification.
38 42
81 24 5
3 36 51
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Original HC ext. pine
Ext. Kraft pulp 1500
% T
otal
sol
ids
Lignin Hemicellulose Cellulose
Loblolly pine sawdust
Hemicellulose extraction Kraft delignification
Loblolly pine pulp 1 g 0.84 g 0.37 g
• Hemicellulose extraction o 0.5% H2SO4, 160 °C, 1 h
• Kraft delignification o 170 °C, effective alkalinity 24%,
sulfidity 66%, H factor 1500 o Carbohydrate composition was
determined by HPLC
Cellulose fiber Chemical/enzymatic depolymerization
Mechanical disruption/ refining
Physico-chemical fractionation
Chemical Diminution/ Dissolution
CNC
Advanced fractionation Size exclusion
Lignocellulose Cellulose nanoparticles
TEM image of commercially purchased CNC. Print Mag: 119,000 X @ 7 in. Source: Dr. Martin, UAF.
100 nm
CHEMICAL STRATEGIES