Recipient Organization
WEST VIRGINIA UNIVERSITY
886 CHESTNUT RIDGE RD RM 202
MORGANTOWN,WV 26505-2742
Performing Department
Forestry
Non Technical Summary
For the past 250 years, linear economy which is characterized by "take, make and waste" has served the global manufacturing industries well. However, increasingly linear economy is making room for the concept of "circular economy" which seeks to decouple economic growth from the extraction and consumption of constrained natural resources (i.e., scarce resources like fossil fuels with negative footprint) and emphasis minimization of waste in manufacturing. This concept also promotes conservation of resources and also significantly enhances profitability of overall manufacturing operation. Closely associated with circular economy is "bio-economy" or bio-based economy. The latter represents "the gradual shift from the use of extracted non-renewable resources to the use of renewable resources". To-date, the Forest Products Industry, like many other industries, is dominated by "linear economy", where biomass such as trees are harvested; converted to primary and secondary products (lumber, pulp and paper, wood composites, furniture, etc.) and the resulting waste-streams combusted; land-filled or used for a myriad of low-value products. This proposal seeks to develop methods for adding value to biomass waste-streams to "support the transformation from a linear on-way cradle to grave manufacturing model toward to a "circular economy". This approach will reduce the carbon footprint of wood processing and increase resource efficiency and conservation of carbon resources. The specific objectives of this study are (1) to convert biomass-waste streams, black liquor (lignin), hemicelluloses, condensed tannins to "green" carbon foams" which has a myriad of industrial applications (insulation, fire resistance), (b) to evaluate betulinol, an extractive from the outer bark of birch and beech, for evaluation as potential insecticides, coatings and some medical applications, and (c) to evaluate suberin fatty acids (SFA) from the outer bark of birch and beech as potential moisture barrier for packages and wood products.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
: 1. To produce "green" carbon foams from black liquor (lignin), condensed tannin and hemicelluloses2. To extract betulinol and SFA from the bark of birch and beech and evaluate their use as insecticides and coatings3. To extract from the outer bark of birch and beech bark suberin fatty acids (SFA) evaluate their potential as moisture barrier for packages and wood products
Project Methods
APPROACH:Two major groups of biomass waste-streams, black liquor (lignin), hemicelluloses, tannins, betulinol and suberin fatty acids will be studied.MATERIALS:Black liquor (lignin, obtained from pulp kills), concentrated sulfuric acid, hydrochloric acid, nitric acid, p-toluene-4-sulfonic acid (Fischer-Scientific); hemicelluloses (extracted from Appalachian hardwoods and commercial sources, Lignol Inc.); condensed tannins (extracted from northern eastern oaks, white and red); furfuryl alcohol (Sigma-Aldrich); zinc and aluminum nitrate (Sigma-Aldrich); diethyl ether, ethanol, (Sigma-Aldrich); suberin fatty acids and betulinol (extracted from birch and beech).Biomass waste-streams - Black liquor, hemicelluloses, and tanninsMETHODS:Carbon foams: Carbon foams are sponge-like light-weight (0.2-0.8 g/cm3) materials with a myriad of applications (high temperature insulation, ablative material, electromagnetic interference shielding, vibration damping, light weight fire resistance, thermal management, catalyst supports, etc.). They have a 3-D network porous structure. To-date, the primary precursors for making carbon foams have been meso-phase pitch and coal/coal-derived products. These are chemicals derived from fossil resources with large carbon and negative footprint. In line with the emerging circular and bio-economy, we propose to employ biomass processing waste-streams (black liquor, tannins, hemicelluloses) as precursors for the manufacture of carbon foams.There are five primary methods for producing carbon foams: (a) blowing of carbon-based precursors followed by carbonization, (b) template carbonization of carbon-based precursors, (c) compression of exfoliated graphite, (d) assembly of exfoliated nano-sheets and (e) others. In the proposed study, we shall employ the first method, blowing of three waste-streams of biomass processing, black liquor (technical lignin - lignosulfonate), hemicelluloses and condensed tannins). The three precursors are all polyols (have multiple -OH groups). Like lignin, tannin is a plant-derived polyphenol. However, lignin has fewer -OH groups than condensed tannins since a number of the free -OH groups in lignin are capped by etherification as aromatic "methoxy" groups. The number of -OH groups in technical lignin will be increased by demethylation to study the effect on carbon foam formation.Additionally, there also two methods for blowing biomass carbon precursors: (a) foaming under under pressure and (b) foaming by use of chemical additives (blowing agent). We shall employ the latter procedure. Further for this procedure, we shall use two approaches - Method A and Method B. The principle that underpins Method A, is that furfuryl alcohol reacts with polyols to form cross-linked condensed polymers. In Method B, which is applicable to only hemicelluloses, is based upon the principle that hemicelluloses like all sugars form viscous mixture upon heating where foaming is induced by additives (zinc nitrate, aluminum nitrate) which during the heating process generate gases (NO2). Hemicelluloses and condensed tannnins will be extracted from Appalachian hardwood chips and bark of red and white northern oaks respectively using hot water and dilute alkali.In Method A, the polyol-based carbon precursors (black liquor, condensed tannins, hemicelluloses) will be stirred mechanically with furfuryl alcohol, additives (graphite, clay), blowing agent (diethyl ether, ethanol) in beaker to form a mixture. Then, an acid catalyst (sulfuric acid, hydrochloric acid, nitric acid, p-toluene -4-sulfonic acid) will be added to the mixture, stirred again and poured into plywood boxes (50 X 50 X 70 mm, 4mm thick). This will initiate an exothermic reaction that will result in condensation of furfuryl alcohol with the carbon precursors (to form hardened polymers) and simultaneous foaming as result of evaporation of the blowing agents (ethanol, diethyl ether) due to the exothermic reaction (condensation reaction with the polyol precursors. After about 10 minutes, the skin of the foam will be cut out and the remaining structure left for four hours for the residual blowing agents to exit the foam structure. Depending upon the carbon precursor and/or catalyst used, the plywood box containing the mixture will be placed in a box oven at 120-160 oC for 8-20 minutes.In Method B, the hemicellulose precursor will be mixed with the blowing agent (zinc or aluminum nitrate) in a beaker and slowly heated (120 oC) to melt and thoroughly mixed to form a viscous mixture. Then, the viscous mixture will be quickly carbonized in a box furnace at 180 oC for about five minutes. For all foams, due to the vertical rising of the gas during foaming, the resultant foams are orthotropic in structure - the foams cells are slightly elongated in the direction of growth. Therefore, there are two measurement directions - the growing direction (z-direction corresponding to the vertical direction) and the flat (xy direction corresponding to the horizontal plane).All the foams will be cut into parallelpipeds. Some of the parallelpipeds will be carbonized in a quartz tube continuously flushed with high-purity nitrogen at 700-900 oC from room temperature at a rate of 4 oC per minute. Once the final temperature is reached, it will held for 2 h; then the furnace will be switched off and the samples allowed to cool to room temperature under nitrogen gas flow.Physical properties [densities (apparent, true), surface area cell structure (SEM, tomography)] and chemical properties (FTIR, XRD, Raman, DSC) and mechanical properties (elastic modulus, compression strength), thermal conductivity, radiative properties, electrical permeability, permeability, thermal coefficient and fire resistance will be determined.Biomass waste-streams - suberin fatty acids and betulinolMETHODS:Suberin fatty acids (SFA) and betulinol will be extracted from the outer bark of birch and beech. First, betulinol, a triterpenoid, will be extracted from Wiley milled ground outer bark of these wood species using trichloroethylene solvent via soxhlet method and ultra-sonic assisted method respectively. The residue will be hydrolyzed by 95% ethanol 0.5M NaOH at 90 oC for 2 h and allowed to cool to room temperature. The residue after filtration will be extracted with hot water; acidified with dilute H2SO4 to precipitate the SFA. The SFA precipitate will be washed with water; filtered and the final SFA lyophilized.Betulinol will be evaluated as an insecticide and a transparent resinous substance for coatings. Betulinol has also be reported to have medicinal applications such as sterilization of bandages and anti-tumor activities. SFA will be evaluated as vapor barrier for packages and wood products.