Volume 3 Issue 3

Traditional chemical industry depends on non-renewable fossil resources and is now facing great challenges. Lignocellulosic materials are the most abundant renewable resources in the world, and their efficient utilization provides a practical route to maintain sustainable development of chemical industry. Modern chemical technology as well as industrial biotechnology will play an important role in comprehensive utilization of lignocellulosic materials in an environmentally friendly way. Bio-refinery is a useful concept in use when considering lignocellulosic materials for a sustainable chemical industry.

Recently an excellent book on lignocellulosic-based biomass has been published. The book can be expected to profoundly impact research and development for sustainable science and engineering. For this reason we have decided to provide our readers with a review of this new ACS Press book entitled “Materials, Chemicals & Energy from Forest Biomass” edited by Dimitris S. Argyropoulos from NC State University. The book features unique, peer-reviewed chapters that were submitted to the American Chemical Society’s Pacifi-Chem 2005 Meeting in Honolulu, Hawaii. It presents a timely and focused review of research efforts encompassing work from the most pertinent derivatives of wood and related resources that include new polymers, composites, niche chemicals, and biofuels. This book will ultimately serve a number of disciplines and promises to focus the discussion of biomass for new avenues of chemicals, fuels, and materials.

In this paper the dependencies of the degree of surface burning and intensity during disc sanding perpendicular to the wood grains of Fagus silvatica L. were examinedfor several machining parameters. Significant impacts of sanding load, thickness, and width of a wooden specimen on the surface burning and disc sanding intensity were evidenced and analyzed by evaluation of multi-factor, non-linear relations. Less important influences of cutting speed and size of grit on the surface burning and the sanding intensity, as well as single sanding cycle time and total sanding operating time on the surface burning were observed.

Alkaline wet oxidation and steam explosion pretreatments of sugarcane bagasse were compared with regard to biomass fractionation, formation of by-products, and enzymatic convertibility of the pretreated material. Wet oxidation led to the solubilisation of 82% of xylan and 50% of lignin, and to a two-fold increase of cellulose content in the pretreated solids, while steam explosion solubilised only 60% of xylan and 35% of lignin and increased cellulose content in the solid material by one third. Wet oxidation formed more aliphatic acids and phenolics, and less furan aldehydes in the liquid fraction than steam explosion did. A better enzymatic convertibility of cellulose was achieved for the wet-oxidised material (57.4 %) than for the steam-exploded material (48.9 %). Cellulose convertibility was lower for the whole slurry than for the washed solids in both pretreatments, but more significantly in steam explosion. This investigation demonstrates the potential of wet oxidation as a promising pretreatment method for enzyme-based bagasse-to-ethanol processes.

Pyrolysis-gas chromatography/mass spectrometry (Py-GC-MS) was applied to measure the lignin syringyl/guaiacyl (S/G) ratio in E. dunni, E. grandis, E. nitens, E. urograndis, and E. urophylla woods. A total of 41 compounds were identified, of which 11 were derived from carbohydrates and 30 from lignins. The S/G ratio was calculated on the basis of the areas of peaks recorded in the pyrograms and compared with the results obtained by alkaline nitrobenzene oxidation. The values of S/G found by pyrolysis were similar for all the species using the compounds guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, 4-ethylsyringol, 4-vinylsyringol, homosyringaldehyde, acetosyringone, and syringylacetone, as lignin markers. The selected markers were efficient for the deter-mination of S/G ratio in eucalyptus wood by Py-GC-MS. The Py-GC-MS technique produced results that are comparable to the nitrobenzene oxidation method, with the advantage of requiring small wood samples and a short analysis time.

Spruce galactoglucomannan is a wood-derived polysaccharide with a modest molar mass that has recently been made available in kg-scale for research and development of value-added products. To promote the application of spruce galactoglucomannans in, for example, food products, it is vital to understand also the rheological behaviour of the mixtures of galactoglucomannans with other polysaccharides. Rheological measurements were applied to study the rheological properties of mixtures of spruce galactoglucomannans and high-molar-mass konjac glucomannan, xanthan, guar gum, locust bean gum, and carrageenan. Shear rate-dependence of viscosity and applicability of the Cox-Merz relationship of mixtures of spruce galactoglucomannans with the other polysaccharides were studied. Spray-dried and ethanol-precipitated galactoglucomannans were also prepared for comparison. The effects of polysaccharide mixture ratio, temperature, ionic strength, and deacetyl-ation are discussed. Mixtures of spray-dried galactoglucomannans and konjac glucomannan showed lower elastic properties than those of ethanol precipitated galactoglucomannans and konjac glucomannan. The viscoelastic spectra of mixtures of both galactoglucomannans and deacetylated galactoglucomannans with konjac glucomannan showed temperature dependency throughout the cooling process. Ionic strength had an effect on the rheological properties of mixtures of galactogluco-mannans with konjac glucomannan. Deacetylation of galactoglucoman-nans did not affect the viscoelastic spectra significantly.

Mechanical compression and electrolyte infusion of wood, pyrolysis, and chemical activation of the resulting charcoals produced enhanced abilities to adsorb lead ion and benzene from model polluted water solutions. Iodine number (F) and methylene blue (E) indices also showed enhancement of surface activity. Ultrasonic techniques revealed a loss of pore structure during wood compression, as water infiltration likewise indicated for the resulting charcoals, but there was not necessarily a loss of adsorption ability for the above adsorbents on subsequent charcoals. Aspen based charcoals activated by pressurized H2O2 showed the most promise among those tested.

In this paper a dependence of the main cutting force upon several machining parameters by wood of black locust (Robinia pseudoaccacia L.) during straight turning was graphically illustrated and analyzed. Evidence for several interactions was found based on multi-factor nonlinear equations evaluated from an experimental matrix.

Baked starch/pulp foams were prepared from formulations containing zero to 25 weight percent of processed Alaskan fish by-products that consisted mostly of salmon heads, pollock heads, and pollock frames (bones and associated remains produced in the filleting operation). Fish by-products thermoformed well along with starch and pulp fiber, and the foam product (panels) exhibited useful mechanical properties. Foams with all three fish by-products, ranging between 10 and 15 wt%, showed the highest flexural modulus (500-770 Mpa). Above 20% fiber content, the modulus dropped considerably in all foam samples. Foam panels with pollock frames had the highest flexural modulus, at about 15% fiber content (770 Mpa). Foams with salmon heads registered the lowest modulus, at 25% concentration. Attempts were also made to cast starch-glycerol-poly (vinyl alcohol) films containing 25% fish by-product (salmon heads). These films showed a tensile strength of 15 Mpa and elongation at break of 78.2%. All foams containing fish by-product degraded well in compost at ambient temperature (24oC), loosing roughly between 75-80% of their weight within 7 weeks. The films degraded at a much higher rate initially. When left in water, foams prepared without fish by-product absorbed water much more quickly and deteriorated faster, whereas, water absorption in foams with fish by-product was initially delayed and/or slowed for about 24 h. After this period, water absorption was rapid.

Hierarchically porous α-Fe2O3 and silica-based Fe2O3 composites (I & II) ranging from nanopores to micrometer-sized pores have been prepared by a nanoscale casting process, using cypress wood tissue template in supercritical carbon dioxide (scCO2). These wood-templated Fe2O3 and its SiO2-based composites with special hierarchical but continuous pore size from 9 nm up to 20 μm, were prepared from scCO2’ hybrid solution with cosolvent and precursor(s). Different characterization techniques such as SEM, XRD, and N2 adsorption-desorption were used to investtig-ate the morphology and structure of Fe2O3 and its composites in different length scales. The Fe2O3 porous material showed a specific character-istic of being accumulated by Fe2O3 granules in the size range ca. 100–200 nm. The SiO2-based Fe2O3 composites exhibited a BET area of 99–104 m2/g, which was much higher than that of pure Fe2O3; this implies that the silica probably exists in the form of a gel skeleton.