Our peer-reviewed sister journal: Lignocellulose (no author payment)
BioResources, Volume 5, Issue 3
The current state of biorefinery development is focused almost entirely on the production of fuel ethanol. However, an ethanol-centric approach misses the crucial example set by the petrochemical industry. The ability to fractionate a raw material, rather than simply pretreating it, enables the parallel production of low value, high volume fuels and high value, low volume chemicals. By developing analogous fractionation processes for biomass, giving separate process streams of cellulose, hemicellulose and lignin, the biorefining industry will be able to recognize the synergistic advantages of producing both energy and profits. PDF
The papermaking industry can benefit a lot from nanotechnology. This versatile technology can also be used in the area of fillers for papermaking wet end applications. In such applications the main technological examples currently available include wet end addition of commercially available nanofillers, formation of nanofiller/fiber or nanofiller/fibril hybrids, development of novel categories of nanofillers such as high aspect ratio nanofillers, and combination of microfillers with nanostructures by specially controlled routes to obtain composite nanofillers. It is worth noting that there are certain challenges associated with nanofillers, such as high cost, difficulty in structure and performance control, poor dispersability and retention, possible severe negative effects on paper strength, possible detrimental interactions between nanofillers with some wet end additives, and the industry-related limitations. However, in the long run, the research and development in the area of nanofillers will surely create many fruitful results. PDF
Kerala in south India grows several cash crops such as banana and pineapple, the crop residues of which are sources of natural fibres that can be used in hand papermaking. Kerala, however, does not have a tradition in hand papermaking. The following is an account of an attempt to popularize the art and craft of hand papermaking among self-help groups as a means of self-employment and waste utilization, using fibres extracted from agriwaste and local plants. PDF
The aim of this research is to examine the market potential for wood plastic composite (WPC) products in the highway construction sector in place of non-renewable materials (e.g. virgin plastic and steel) and preservative-based products (treated wood). State-level transportation officials indicate that the majority of highway construction purchases are conducted by highway construction contractors. Results from a mail survey of highway contractors in eight western U.S. states indicate that a substantial volume of highway construction material may be suitable for substitution with WPCs. Overall, respondents were not familiar with WPC as a material, but compared it favorably with other materials commonly used in the sector. When making purchase decisions, respondents were most concerned with products meeting regulatory specifications, cost, availability, and trust in quality. Attributes related to sustainability, location of manufacture, and content of recycled material were viewed as less important. PDF
Xing, M., Yao, S., Zhou, S.-K., Zhao, Q., Lin, J.-H., and Pu, J.-W. (2010). "The influence of ultrasonic treatment on the bleaching of CMP revealed by surface and chemical structural analyses," BioRes. 5(3), 1353-1365.
Effects of ultrasonic pretreatment on the bleaching of chemimechanical pulp (CMP) fiber of triploid Chinese white Poplar were investigated. Before single-stage hydrogen peroxide bleaching, CMP was sonicated at 1.5% pulp consistency and 50oC for 20min with 90% amplitude and 20s pulse; these conditions showed the most favorable effect of a 3.5% ISO increase of brightness, reaching a final value of 80.2% ISO. The benefit may be because the ultrasound can accelerate heterogeneous reactions, which arise from the impingement of microjets and shockwaves on the solid surface, which are then capable of inducing striking changes in surface morphology, composition, and reactivity. To prove the theory, the surface structure and surface morphology were investigated by SEM and AFM, and the crystalline structure and characteristics of the cellulose in terms of XRD and FT-IR were also evaluated. PDF
Kline, L. M., Hayes, D. G., Womac, A. R., and Labbé, N. (2010). "Simplified determination of lignin content in hard and soft woods via UV-spectrophotometric analysis of biomass dissolved in ionic liquids," BioRes. 5(3), 1366-1383.
A new simple and safe method for quantifying lignin content in lignocellulosic biomass is described. The approach consists of measuring the absorbance of a solution of whole biomass dissolved in the ionic liquid 1-n-butyl-3-methyl imidazolium chloride, [Bmim][Cl], at 440 nm via ultraviolet- (UV-) visible spectrophotometry. An extinction coefficient for a lignin standard, highly pure lignin isolated from biomass through an organosolv process, is used in conjunction with the Beer-Lambert Law to calculate the lignin concentration. Principal component analysis (PCA) of Fourier Transform-Infrared (FTIR) spectra collected for several different lignin standards was performed to understand the differences in their chemical structure and composition (e.g., the relative amounts of syringyl and guaiacyl units). A rapid FTIR analysis of the whole biomass sample with unknown lignin content is required to assist in the proper selection of the lignin standard for the subsequent spectrophotometric analysis. The proposed method was tested and validated on two biomass types: Yellow poplar and Southern pine. The spectrophotometric approach yielded lignin contents for Yellow poplar and Southern pine of 25.7 ± 1.1% and 26.7 ± 0.7%, respectively, which are comparable to the values obtained by a standard wet chemical protocol, 25.1% ± 0.7 and 26.6 ± 0.4%, respectively. PDF
Babayemi, J. O., Dauda, K. T., Kayode, A. A. A., Nwude, D. O., Ajiboye, J. A., Essien, E. R., and Abiona, O. O. (2010). "Determination of potash alkali and metal contents of ashes obtained from peels of some varieties of Nigeria grown Musa species," BioRes. 5(3), 1384-1392.
Potash alkali and metal contents of ashes obtained from peels of six varieties of Nigeria Musa species were investigated. The varieties of Musa species – Musa paradisiaca (plantain), Musa ‘Gross Michel’ (Igbo banana), M.sapientum L. (paranta), Musa ‘Wild Banana’ (omini), Musa ‘Red’ (sweet banana), and Musa ‘Fugamo’ (somupeke), were investigated. The moisture, dry matter, ash and alkali contents; concentration of metals in the ashes and in the contents extracted with water from the ashes; and the ratio of potassium to other metals in the ashes and in the corresponding extracts were determined. Moisture contents ranged from 80.9 to 86.7%; dry matter content, 13.3 to 19.1%; ash content, 6.3 to 12.0%; alkali content, 69.0 to 81.9% of ash and 4.7 to 9.6% of dry sample. Samples ranged between 2.60 and 720mg/kg and in the corresponding extracts, BDL to 500.49mg/kg; ratio of concentration of potassium to other metals in the samples, 0.6 to 395; and in the extracts, 0.5 to 313. Gross michel showed the highest concentration of K (750mg/kg) while omini banana gave the lowest average value (112.70mg/kg). PDF
The paracrystallinity of cellulose samples was studied with a complex of investigation methods including X-ray, NMR, sorption, calorimetry, and some others. It was found that the paracrystalline fraction of cellulose is located on the surface of crystallites as thin monomolecular layers having an average thickness of 0.4 nm. The paracrystalline surface layers have distorted and loose packing that is characterized by a high distortion parameter δp = 0.18, increased specific volume Vp=0.664 cm3/g, and decreased specific gravity ρp= 1.51 g/cm3. The paracrystalline fraction of the crystallite can be quantified by the parameter (α), which has an expressed influence on some properties of cellulose. Increasing of the α-value causes expansion of inter-plane distances in the C1 unit cell, as well as promotes mercerization and dissolution of cellulose. PDF
Beis, S. H., Mukkamala, S., Hill, N., Joseph, J., Baker, C., Jensen, B., Stemmler, E. A., Wheeler, M. C., Frederick, B. G., van Heiningen, A., Berg, A. G., and DeSisto, W. J. (2010). "Fast pyrolysis of lignins," BioRes. 5(3), 1408-1424.
Three lignins: Indulin AT, LignoboostTM, and Acetocell lignin, were characterized and pyrolyzed in a continuous-fed fast pyrolysis process. The physical and chemical properties of the lignins included chemical composition, heat content, ash, and water content. The distributed activation energy model (DAEM) was used to describe the pyrolysis of each lignin. Activation energy distributions of each lignin were quite different and generally covered a broad range of energies, typically found in lignins. Process yields for initial continuous-fed fast pyrolysis experiments are reported. Bio-oil yield was low, ranging from 16 to 22%. Under the fast pyrolysis conditions used, the Indulin AT and LignoboostTM lignin yielded slightly more liquid product than the Acetocell lignin. Lignin kinetic parameters and chemical composition vary considerably and fast pyrolysis processes must be specified for each type of lignin. PDF
Corporate environmental sustainability calls for sustainable product manufacturing with less creation of waste material or increased reuse of waste materials. One example is the use of keratin fiber from the poultry industry and cotton linter from the textile industry for paper and tissue manufacturing. In this paper, the feasibility of using these waste fibers to make paper was demonstrated in handsheets. The properties of these handsheets were compared to the properties of handsheets made with standard bleached eucalyptus tropical hardwood fibers. A blend of cotton linter and keratin fibers at 80/20 and 60/40 ratios showed a 59% and 73% improvement in sheet bulk, respectively, compared to eucalyptus handsheets. Similarly, air permeability of the cotton / keratin fiber handsheets improved 414% and 336%, respectively, versus the eucalyptus. However, the tensile index of the cotton and keratin fiber blends was lower than the eucalyptus sheets. There was no remarkable difference in water absorbency up to 20% keratin fiber. Above 20% of keratin fibers the water absorbency started to decrease, which is likely attributable to the hydrophobic nature of the protein-based keratin fiber. PDF
This paper reports results concerning characterization and improvement of biological quality of beechwood prehydrolysate in order to adapt the Candida Scottii yeast to this nutritive medium. Some difficult aspects caused by the presence of lignin compounds in the prehydrolysate are mentioned. Studies carried out also made it possible to evaluate yeasts as regards the chemical composition and their nutritive value, tested in case of a mixed fodder used for chicken breeding. PDF
This study was carried out to identify an appropriate alkaline pulping condition for Malaysia cultivated kenaf (Hibiscus cannabinus L.). The chemical composition of the kenaf bast and core fibers, and also whole stalk with different growing time were examined prior to pulping attempts. The results of various soda-AQ pulping showed that the degree of carbohydrate degradation and delignification increased with the increase of active alkali and cooking temperature, but decreased with the increase of liquor to material (L:M) ratio. The most satisfactory properties of pulp and handsheets from bast could be attained by employing soda-AQ pulping with 19.4% active alkali, 0.10% AQ, and L:M ratio of 7:1 cooked for 2 hours at 160˚C. Besides, it was also found that a mild alkaline pre-impregnation prior pulping improved the pulp viscosity and handsheets’ strength properties, especially the tensile index and folding endurance effectively. Moreover, among the three alkaline pulping processes—kraft, kraft-AQ, and soda-AQ—the results of pulp and handsheet properties showed that the soda-AQ pulp was comparable or even slightly of higher quality than the kraft pulps. Between the unbeaten bast and core soda-AQ handsheets, the strength properties of the core were higher than the bast, as the thin-walled core fibers exhibited much better conformability than the thick-walled bast fibers. PDF
Forest industries look for multiple utilizations for their timber production. In Brazil, the genus Eucalyptus has a great potential for solid wood products; however, only a small amount of Eucalyptus is used as sawn timber. About 50% of the log volume ends up as waste during mechanical processing, resulting in serious economic and environmental problems. In most cases, such residue is discarded at random or used as fuel, and in this context the sustainable management of processing industrial waste is an urgent necessity. Parallel to this, Eucalyptus has not been employed for small wooden object (SWO) production. Hence, the aim of this work was to evaluate the performance of small wooden objects produced with Eucalyptus urophylla, E. camaldulensis, and E. grandis waste from sawmilling. Brazilian craftsmen manufactured SWOs with Eucalyptus, and these crafted objects were presented at exhibits and trade fairs for assessment. The proposed small wooden objects made with Eucalyptus residues exhibited satisfactory performance and achieved excellent acceptance by the visitors. This work gave evidence that the use of sawmill waste as raw material for small wooden object manufacture has potential to generate income for economically underprivileged communities near to a plantation. PDF
The bending moment capacity was studied under the diagonal tensile and compression loadings of miter corner joints with dovetail fitting in frames made with medium density fiberboard (MDF). The influence of the type of adhesive in the joints with dovetail fitting on bending moment capacity under diagonal tensile and compression loading were considered, and the joints without adhesive were compared. A total of 80 each miter frame corner joint specimens with dovetail fitting were made. Polyvinyl acetate (PVAc), polyurethane (PU), and cyanoacrylate (CA) adhesives were used, and 20 specimens were prepared without adhesive (WA) with dovetail fitting. MDF was used as a frame material, as in normal practice. The specimens were subjected to diagonal tensile and compression loadings in accordance with ASTM-D 143-94. The data were analyzed statistically. The highest bending moment capacity under diagonal tensile loading (46.09 Nm) was obtained in the specimens bonded with CA adhesive and the highest bending moment capacity under diagonal compression loading (72.04 Nm) was obtained in the specimens glued with PVAc adhesive. Other than this, since there is no difference between these and the unbonded joints, the PU adhesive was not effective in increasing the bending moment capacity under diagonal tensile loading, and the PU and CA adhesives were not effective in increasing the bending moment capacity under diagonal compression loadings. PDF
Superabsorbent polymer was prepared by graft polymerization of acrylic acid onto the chain of cellulose from flax shive by using potassium persulfate (KPS) as an initiator and N,N’-methylenebisacrylamide (MBA) as a crosslinker under microwave irradiation. SEM photographs were also studied for more information about the shive, cellulose from shive, and the superabsorbent polymer. The structure of the graft copolymer was confirmed by FT-IR spectroscopy and thermogravimetric analysis (TGA). The biodegradability in soil was measured at 32 and 40 oC. The polymer was porous, and thermal stability of the polymer was observed up to approximately 200 oC. FT-IR analysis indicated that acrylic acid in polymer was successfully grafted onto the cellulose. The graft copolymer was found to be an effective superabsorbent resin, rapidly absorbing water to almost 1000 times its own dry weight at pH around 7.3. The water absorbency in 0.9% NaCl, KCl, FeCl3 solutions and urine were 56.47 g/g, 54.71g/g, 9.89g/g and 797.21g/g, respectively. The product biologically degraded up to 40% at 40 oC in 54 days, which shows good biodegradability. PDF
Lee, J. M., Jameel, H., and Venditti, R. A. (2010). "One and two stage autohydrolysis pretreatments for enzyme hydrolysis of coastal Bermuda grass to produce fermentable sugars," BioRes. 5(3), 1496-1508.
Coastal Bermuda grass (CBG) is an agricultural residue with considerable potential as a feedstock for lignocellulosic-based ethanol. The treatment of biomass with water at high temperature, termed autohydrolysis, can be used to recover sugars in the filtrate and to improve enzyme digestibility of the pretreated solids. The effect of a two- stage autohydrolysis process with respect to total sugar recovery relative to a one stage process was investigated. CBG was subjected to lab scale one-stage (150, 160, and 170 °C) and two-stage (150/170 °C and 160/170 °C) isothermal autohydrolysis processes followed by enzyme hydrolysis on the residual solids with different loadings (5 to 30 FPU/g). Two-stage autohydrolysis (160/170 °C) solubilized 94.2% of the hemicellulose based on the original CBG material but only 17.7% of the cellulose and 30.4% of the lignin. Increases in the severity factor (a combination of time and temperature) of autohydrolysis pretreatments decreased the recoverable carbohydrates and total solids. Two-stage autohydrolysis enhanced enzyme digestibility of the cellulose in pretreated solids relative to one-stage autohydrolysis, especially at higher values of FPU/g. The overall total theoretical sugar recovery achievable by the two stage process was 57.8% and for the one stage process only 51.6% with 30 FPU/g. This marginal increase would have to be considered relative to increased complexity of operations when deciding whether to implement one or two stage autohydrolysis. PDF
The formation of vanillin and syringaldehyde during an oxygen delignification process was evaluated. The cleavage of conjugated Cα-Cβ bonds in phenolic lignin caused by the attack of oxygen leads to the formation of aromatic aldehydes and ketones. The formation mechanism was confirmed by the organic compounds identified in the spent liquor by GC/MS. Additionally, the formation of aromatic aldehydes and ketones of hardwood, softwood, and grass was investigated. The results showed that the formed aromatic aldehydes and ketones were related to the units of lignin structure. Among the aromatic aldehydes and ketones present in the spent liquor from oxygen delignification, vanillin and syringaldehyde are of high content, making the spent liquor a potential resource for vanillin and syringaldehyde production. PDF
Rekaby, M. M., El-Thalouth, I. A., Rahman, A. A. H., and El-Khabery, S. A. E. (2010). "Technological evaluation of carboxymethyl sesbania galactomannan gum derivatives as thickeners in reactive printing," BioRes. 5(3), 1517-1529.
Galactomannan gum isolated from the seeds of sesbania was subjected to chemical modification via carboxymethylation in non-aqueous medium using monochloroacetic acid under the catalytic action of sodium hydroxide. The obtained derivatives were subjected to measuring the degrees of substitution (D.S.), rheological properties of their pastes, and evaluated as thickeners in printing cotton fabrics with reactive dyes. Highly substituted derivatives could be used successfully as thickening agents in printing cotton fabrics either alone or in admixture with sodium alginate. Prints acquire soft handle, colour strength (K/S), and fastness properties nearly identical to corresponding samples that were printed using sodium alginate. PDF
The objective of this study was to test the bonding performance of nanoscale bondlines, which were fabricated with polyelectrolytes by layer-by-layer assembly process onto wooden substrates. In this study, environmental scanning electron microscopy (ESEM) was used to characterize adsorbed multilayers of polyacrylic acid and polyallylamine hydrochloride on the wood surface. Cross-linking between PAA and PAH layers at various temperatures was studied using Fourier Transform Infrared Spectroscopy (FTIR). The evaluation of polyelectrolyte multilayers as bonding agents for wood was conducted through compression shear block and flexural bending tests. Altogether, this research demonstrates a route to utilize nanoscale coatings as bonding agents. PDF
Azizi Mossello, A., Jalaluddin, H., Resalati, H., Rushdan I., Paridah, M. T., Fallah Shamsi, S. R. and Ainun, Z. M. A. (2010). "Soda-anthraquinone pulp from Malaysian cultivated kenaf for linerboard production," BioRes. 5(3), 1542-1553.
The goal of this study was to prepare soda- anthraquinone pulp from kenaf whole stem and to compare the resultant core and bast pulps for linerboard production. Pulping was done under mild cooking conditions (active alkali 12-15%) with a cooking time of 30-90 min and a temperature of 160ºC. During the pulping process, kappa numbers ranged from 56.0 to 20.6, while total yields varied from 58.4 to 54.2% with a rejection rate of 2.3 to 0.1%. Based on the quality of pulp produced, kappa numbers 49.4 and 25.4 was selected as symbolic of high and low pulps respectively. The results of the study revealed significant difference between the properties of core, whole stem (KHK and KLK), and bast pulps. Core pulps with low freeness and high drainage time the study found produced sheets with greater density, tensile index, burst index and RCT, with lower light scattering coefficient and tear index than bast pulp. Whole stem pulps showed properties between those of core and bast pulps. Moreover, KLK with high drainage time produced papers with significantly higher strength properties than KHK. PDF
A new method was developed for production of low molecular weight chitosan, in which high molecular weight chitosan was treated with dilute sulfuric acid at 120°C. Chitosan was dissolved in the acid solution in a few minutes, and as depolymerized to low molecular weight chitosan by longer times. Low molecular weight chitosan was recovered from the acid by cooling down the solution and increasing the pH to 8-10. A low molecular weight chitosan with Mv (viscosity average molecular weight) of 174×103 was prepared from a high molecular weight chitosan (Mv = 1,388×103) with 82% recovery by using 72 mM sulfuric acid solution for 30 min. Increasing the time to 240 min reduced the Mv to 24×103, though the recovery of chitosan was reduced to 54%. Higher concentrations of acid (216 and 360 mM) resulted in higher depolymerization degrees and lower recoveries of chitosan in identical treatment times. Analysis of glucosamine and N-acetyl glucosamine showed that the prepared low molecular weight chitosan had more than 80% purity. PDF
Sugarcane bagasse was delignified with alkali and peracetic acid in a two-stage process to obtain pulps with high yield and low kappa number. The experimental results indicated that alkali pretreatment prior to peracetic acid (PAA) delignification could significantly reduce PAA loading by partially removing lignin and swelling the fibers. An optimum condition for the two-stage delignification was obtained for pulping of sugarcane bagasse. The pulps were further characterized by chemical composition analysis, strength property tests, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Thermal Gravimetric Analysis (TGA). It was found that the alkali-PAA process could be conducted under milder conditions with resulting higher pulping selectivity, higher degree of polymerization (DP), and superior mechanical properties of pulps, compared to the kraft pulping process. Both kraft pulps and alkali-PAA pulp had similar FTIR spectra, XRD spectra, and TGA (DTG) curves. However, further analysis indicated that the alkali-PAA pulp had higher infrared crystallization index and cellulose crystallinity. PDF
Statistically based experimental designs were used to construct a mixed-culture community for maximizing the chemical oxygen demand (COD) degradation of pulping effluents by the use of six different strains, i.e., Agrobacterium sp., Bacillus sp., Enterobacter cloacae, Gordonia, Pseudomonas stutzeri, and Pseudomonas putida. Significant effects of single and mixed strains on COD degradation were quantified first by applying a fractional factorial design (FFD) of experiments, and four strains were selected as the main driving factors in the process of biodegradation of effluents. Then the Steepest Ascent method was employed to approach the experimental design space, followed by an application of response surface methodology to further optimize the proportion of cell concentration for different strains in pulping effluent. A quadratic model was found to fit COD removal efficiency. Response surface analysis revealed that the optimum levels of the tested variables for the degradation of COD, and optimized cells concentrations (OD600) of four strains in mixed-culture community were 0.35 Agrobacterium sp., 0.38 Bacillus sp., 0.43 Gordonia sp., and 0.38 P. putid., respectively. In a confirmatory experiment, three test runs were performed by using the optimized conditions, and a COD removal efficiency of (65.3 ± 0.5)% was observed, which was in agreement with the prediction. PDF
Azizi Mossello, A., Harun, J., Ibrahim, R., Resalati, H., Shamsi, S. R. F., Tahir, P. M., and Yusoff, M. N. M. (2010). "Evaluation of linerboard properties from Malaysian cultivated kenaf soda-anthraquinone pulps versus commercial pulps," BioRes. 5(3), 1595-1604.
Malaysian cultivated kenaf has been identified as a suitable raw material for linerboard production. This study examines the soda-antraquinone (soda-AQ) pulp of kenaf fibers versus old corrugated container (OCC) and unbleached softwood kraft pulps as the main sources for linerboard production. The results showed significant differences among the pulp properties. The unbleached kraft pulp with very high freeness required high beating to reach an optimized freeness and produced paper with the highest strength properties, except for tear resistance. The OCC gave paper with the lowest strength properties. In the case of kenaf fractions, bast pulp with high freeness needed less beating than softwood and produced paper with high tear resistance. Core fiber, which had the lowest freeness and highest drainage time, led to paper with high strength but very low tear resistance. Kenaf whole stem pulp showed intermediate properties between core and bast and close to those of unbleached softwood pulp, but with very lower beating requirement. Finally, kenaf whole stem, due to its strength properties, moderate separation cost, and simple pulping process, was judged to be more suitable for commercialization for linerboard production in Malaysia. PDF
Bagasse is a renewable resource characterized by its low cost and environmental friendliness. In this work a novel technological process was proposed to make flame retarding composites (BFRCs) by using bagasse fiber. The bagasse was disintegrated by twisting it up and applying high consistency refining, and then it was used to prepare BFRCs via hot pressure. Chemical groups and thermal properties of bagasse fiber were studied through the use of FTIR spectroscopy, a universal mechanical testing machine, and TGA, while properties of BFRCs were also analyzed by SEM, and the surface water resistance and burning characteristics were measured. Results showed the pyrolysis temperature of bagasse fibers to be about 273oC. Chemical groups were not changed, while the content of groups was reduced a little during the manufacturing process. The BFRCs showed good performance for water resistance, and the optimum value was 1.7 g. They also had good flame retardant performance. The index of flame spread was 13.6 and the smoke index was 108, which reaches Class A by the ASTM E84-08 Standard. PDF
Kabir, M. A., Huque, M. M., Islam, M. R., and Bledzki, A. K. (2010). "Mechanical properties of jute fiber reinforced polypropylene composite: Effect of chemical treatment by benzenediazonium salt in alkaline medium," BioRes. 5(3), 1618-1625.
Raw jute fiber was treated with o-hydroxybenzenediazonium salt (o-HBDS) in alkaline media. Raw and modified jute fiber were used to prepare composites by mixing with polypropylene (PP) plastic in different weight fractions (20, 25, 30, and 35%) of jute fiber. The mechanical properties except elongation at break of o-HBDS-treated (in alkaline medium) jute fiber-PP composite were higher than those of PP alone, raw jute fiber-PP composites, and alkali-treated jute fiber-PP composites. The elongation at break of treated jute-PP composite decreased to a large extent as compared to that of PP. The increase of tensile strength, tensile modulus, flexural strength, flexural modulus, and Charpy impact strength were found to be exceptionally high (in some cases ~200%) as compared to those of literature values. PDF
Porankiewicz, B., Banski, A., and Wieloch, G. (2010). "Specific resistance and specific intensity of belt sanding of wood," BioRes. 5(3), 1626-1660.
This paper estimates and discusses the specific belt sanding resistance K (N·cm-2) and specific belt sanding intensity SI (g·cm-2·min-1), for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v). PDF
Rice bran carbon (RBC) prepared from rice bran (an agricultural waste) was successfully utilized for the removal of hexavalent chromium from aqueous solution. The potentiality of RBC was tested and compared with commercial activated carbon (CAC), and it was found that RBC removed 95% of hexavalent chromium at pH 2, 1000 µM Cr(VI) concentration, temperature 30 oC, and adsorbent dose of 2 g/L. The maximum uptake of total chromium obtained by applying the Langmuir isotherm model was 138.88 mg/g for RBC, which was found comparable to that obtained by utilizing CAC (116.28 mg/g) at 40 oC. The removal of Cr(VI) was found maximum at a proton to chromium ratio of 10 and chromium to carbon ratio of 0.052, and these ratios were found to be applicable over a range of Cr(VI) concentrations. The removal of Cr(VI), at low pH (< 2.0), was not only due to sorption of Cr(VI) but also because of reduction of Cr(VI) into less toxic Cr(III), which was also adsorbed on the surface of the sorbent. The rate of reduction removal of Cr(VI) followed pseudo-first order kinetics, whereas the sorption of total chromium followed pseudo-second order kinetics for both the types of activated carbons. PDF
Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic reduction of fresh water consumption in the industry enhances microbial development. Depending on their chemical nature, biocides may interfere with typical wet-end chemistry additives and furnish. A reference wet-end chemistry was set (including fixing aid, dry strength aid, sizing agent, and retention system), then biocides were added to the furnish (bleached virgin fibres + mineral filler) prior to handsheet making. Four of the tested biocides (organo-sulfur, dibromonitrilopropionamide, isothiazoline, and glutaraldehyde) were not found to interact with wet-end chemistry. On the other hand, the tested quaternary ammonium salt biocide showed very detrimental effects: it reduced filler retention in the sheet, decreased sheet strength, and destroyed sizing (sheet hydrophobicity). PDF
Meenakshi, Singh, G., Bhalla, A., and Hoondal, G. S. (2010). "Solid state fermentation and characterization of partially purified thermostable mannanase from Bacillus sp. MG-33," BioRes. 5(3), 1689-1701.
Bacillus sp. MG-33 was isolated from the desert of Rajasthan (India). The organism produced 500 and 200 Ug-1 of thermostable mannanase (after 96h) in solid state fermentation (SSF) of wheat bran and wheat straw rich-soda pulp at the moisture ratio of 1:1.5 and 1:3 at 30ºC, respectively. Two-step partially purified mannanase was optimally active at 65ºC and was 100% thermostable at 55 to 60ºC for 2h and also retained more than 50% residual activity at 65ºC for 2h. A pH of 6.5 was optimum for enzyme activity and 100% stability up to 4h at this pH. Mannanase activity was slightly enhanced by Ca2+, Fe3+, and Mg2+, while 100% activity was retained in the presence of Ba3+, Li+, and NiCl2 at 1.0-10mM. 1M NaCl and urea did not reduce the enzyme activity. The Km and Vmax of mannanase were 0.2mgml-1 and 60Umg-1ml-1, respectively. Hydrolysis of locust bean was rapid and linear between 5 and 20 min, and ~300µgml-1 mannose was obtained after 20 min of catalytic reaction by enzyme at 65ºC. TLC was used to confirm the mannose as an end product after hydrolysis of locust bean gum. PDF
Sheikhi, P., Talaeipour, M., Hemasi, A. H., Eslam, H. K., and Gumuskaya, E. (2010). "Effect of drying and chemical treatment on bagasse soda pulp properties during recycling," BioRes. 5(3), 1702-1716.
Effects of chemical treatment on the potential for recycling of bagasse pulp were evaluated. The pulps were recycled three times with water (without treatment), sodium hydroxide, and ethylamine separately. Changes in crystalline structure of the pulp during recycling were investigated by x-ray diffractometry. Water retention content was measured by centrifugation. Morphological changes were investigated by scanning electron microscopy. The breaking length, burst index, fold number, water retention value, and density decreased continuously after recycling. Chemical treatment didn't have a positive effect on the swelling of the recycled pulp. But the light scattering coefficient increased continuously. The crystallinity index and crystallite size increased to an extent, compared to virgin pulp. Some particles on recycled fibers with chemical treatment and treated handsheets had more curled fibers than untreated handsheets. PDF
Wang, K., Jiang, J.-X., Xu, F., Sun, R.-C., and Baird, M. S. (2010). "Influence of steam pressure on the physico-chemical properties of degraded hemicelluloses obtained from steam-exploded Lespedeza stalks," BioRes. 5(3), 1717-1732.
Steam explosion pretreatment was used to release hemicelluloses from the stalks of Lespedeza crytobotrya, a potential woody biomass crop. Hemicelluloses from Lespedeza crytobotrya subjected to five different pretreatment severities were extracted with 60% aqueous ethanol solution containing 1% NaOH, characterized by component analysis, gel permeation chromatography (GPC), FT-IR, NMR spectroscopy, and thermal analysis, and compared with hemicelluloses obtained from untreated stalks. It was found that the hemicellulosic fractions mainly consisted of arabinoxylans and β-glucans or xyloglucans. Steam explosion pretreatment yielded noticeable degradation and debranching reactions, illustrated by a linear decrease of molecular weight and Ara/Xyl ratio with increasing severity. For further high-value utilization of the hemicellulosic polymers, steam explosion at 20 or 22.5 kg/m2 for 4 min is promising because of improved extraction efficiency and avoidance of over-drastic degradation of the polymers. PDF
Non-wood fibers such as bamboo and wheat straw have been playing important roles in the pulp and paper industry in China. In this study an ECF-bleached bamboo kraft pulp was compared with a bleached softwood kraft pulp (NBSK) as the reinforcement pulp in fine paper production. Areas that were examined include the refining of pure fibers, influence of bamboo on dewatering, retention, and sizing. The influence of bamboo kraft pulp as a part of a furnish replacing NBSK was compared as well. Results show that fiber shortening was more prominent with bamboo when refined. This resulted in a higher amount of fines, and addition wet-end chemicals may be required to compensate. Handsheets with bamboo as a reinforcement fiber showed similar mechanical and optical properties to handsheets containing NBSK. PDF
Twin-screw extrusion pulping is a new approach to the manufacture of pulp for paper production, designed for non-wood feedstocks. In this research, the production of pulp from rice stem with a newly fabricated twin-screw extruder was investigated. Extrusion pulping of rice stem was conducted following a central composite design using a two-level factorial plan involving three process variables (pretreatment NaOH concentration: 0.4, 0.8, 1.2%; extrusion temperature: 40, 60, 80 oC; and extruder rotational speed: 55, 70, 85 rpm). Responses of pulp and handsheets properties to the process variables were analyzed using statistical software (MINITAB 15). As the results show, pulping of rice stem fiber can be done at a relatively short pretreatment time about 4 hours and a low NaOH concentration about 0.8% by twin-screw extruder with limit extrusion temperature of about 80 oC and extruder rotational speed about 85 rpm. The effect of pretreatment solvent, NaOH, is greatly enhanced by increases in the extrusion temperature. Analysis of the results revealed that this process has suitable potential to be used to obtain a pulp with yields approximately equivalent to neutral sulfite semi-chemical pulping at fixed kappa number, which is applicable for fluting paper and linerboard production. PDF
Li, M.-F., Fan, Y.-M., Sun, R.-C., and Xu, F. (2010). "Characterization of extracted lignin of bamboo (Neosinocalamus affinis) pretreated with sodium hydroxide/urea solution at low temperature," BioRes. 5(3), 1762-1778.
Ball-milled bamboo (Neosinocalamus affinis) was first treated under ultrasound at 20 oC in 95% ethanol solution for 0 to 50 min, dissolved in sodium hydroxide/urea solution (7% NaOH/12% urea) at –12 oC, and then extracted with ethanol and dioxane to isolate lignin. The structure of the isolated lignin was characterized with a set of wet chemical and spectroscopic methods, including UV, FT-IR, 13C NMR, and HSQC spectroscopies. The results showed that the lignin extracted from bamboo consisted of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) type lignins with minor cinnamate units. The predominate lignin inter-units were β-O-4´ ether linkages, followed by phenylcoumaran and a lower proportion of resinol and spirodienone. It was also found that the ester groups of lignin were cleaved during the pretreatment process with cold alkaline solution. PDF
As a pulp bleaching agent, dimethyldioxirane (DMD) is effective and selective. In this study, it was employed as a delignifying agent or as an activating agent for hydrogen peroxide treatment in bleaching acetate-grade pulp. Brightness, kappa number, degree of polymerization (DP), and alpha-cellulose content were evaluated to determine the optimal charges of DMD: 2.5% AO, and 4% HSO5-, respectively. Results from the totally chlorine-free (TCF) sequences MEQMPA, MEpQMPA, and OQMPA suggested that DMD is both effective and selective as a delignifying agent but not as a brightening agent as compared to oxygen. And in a long sequence for the bleaching of dissolving pulp, acid treatment can be used in two approaches: to remove the metal ions without washing before the chelation stage, and to reduce hemicellulose and ash in the final stage. PDF
In the present communication, the effect of positional density on the DC electrical conductivity of bamboo fibres was studied. A comparative study was made between the DC conductivity behavior of bamboo fibres taken from upper and lower portions of bamboo. Four samples from each portion going from centre to periphery were taken. Bamboo fibers taken from the upper portion were less dense, hence showing lower values of DC conductivity. In spite of the lower portion of bamboo being more dense, it showed higher values of DC conductivity, which is attributed to moisture content. Bamboo fibres from centre to periphery were taken from the strips cut at 2 mm distance from centre. The DC conductivity increased from centre to periphery. A theoretical model was developed and verified with the experimental results. It was also found that experimentally determined σdc values of bamboo fibres taken from different radial locations from center to periphery were in agreement with those values obtained from the proposed equation. PDF
In order to obtain the adhesion force of fiber in a paper sheet easily, the relationships between internal bonding strength (IBS) and surface lignin content of masson pine CTMP treated with peracetic acid (PAA) have been investigated with XPS technique, and the surface morphology of fibers was also imaged by AFM. The results showed that the extent of lignin covered on the fiber surface was two times as high as that of whole pulp lignin, and the IBS was inversely proportional to surface lignin. The relationship between IBS and lignin coverage was formulated based on the experimental data. The mutual adhesion forces, cellulose-to-cellulose and lignin-to-lignin, were calculated using these equations, and the results were 28.69 mN/m and 2.487mN/m, respectively. PDF
A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol) (PEG 1000) was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid) (PLA) and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc) were characterized by tensile testing machine, atomic force microscope (AFM), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils. PDF
In this study, the effect of pine cone ratio on wettability and surface roughness of particleboards was examined. Contact angles of water on the produced samples were measured with a goniometer. The surface roughness of the samples was determined with a fine stylus tracing technique. Particleboards made from 100% wood particle had the lowest average contact angle (95.6°), but the highest was for the particleboards containing 50% pine cone (116.3°). Average surface roughness was higher for samples containing a higher amount of pine cone in the mixture. The smoothest surface (9.77 μm Ra) was observed when panels were produced using 100% wood particles. On the other hand, the roughest surface (15.50 μm Ra) was found for the samples containing 50% cone particles in the mixture. Rmax and Rz parameters had similar trends to the Ra values. Increasing the pine cone ratio in the mixture negatively affected the contact angle and surface roughness parameters of the particleboard. PDF
El-Wakil, N. A., Fahmy, Y., Abou-Zeid, R. E., Dufresne, A., and El-Sherbiny, S. (2010). "Liquid crystalline behavior of hydroxypropyl cellulose esterified with 4-alkoxybenzoic acid," BioRes. 5(3), 1834-1845.A series of 4- alkyoxybenzoyloxypropyl cellulose (ABPC-n) samples was synthesized via the esterification of hydroxypropyl cellulose (HPC) with 4-alkoxybenzoic acid bearing different numbers of carbon atoms. The molecular structure of the ABPC-n was confirmed by Fourier transform infrared (FT-IR) spectroscopy and 1H NMR spectroscopy. The liquid crystalline (LC) phases and transitions behaviors were investigated using differential scanning calorimetry (DSC), polarized light microscopy (PLM), and refractometry. It was found that the glass transition (Tg) and clearing (Tc) temperatures decrease with increase of the alkoxy chain length. It was observed that the derivatives with an odd number of carbon atoms are non-mesomorphic. This series of ABPC-n polymers exhibit characteristic features of cholesteric LC phases between their glass transition and isotropization temperatures. PDF
A study has been carried out to evaluate physical and flexural properties of composites made by areca fibers with a randomly distributed orientation of fibers. The extracted areca fibers from the areca husk were alkali treated with potassium hydroxide (KOH) to get better interfacial bonding between fiber and matrix. Then composites were developed by means of a compression molding technique with varying process parameters, such as fiber condition (untreated and alkali treated), and fiber loading percentages (50% and 60% by weight). The developed areca fiber reinforced composites were then characterized by physical and flexural tests. The results show that flexural strength increases with increase in the fiber loading percentage. Compared to untreated fiber, significant change in flexural strength has been observed for treated areca fiber reinforcement. PDF
The objective of this research was to investigate the utilization of olive mill sludge (OMS) as an alternative to wood in the manufacture of the medium density fiberboard (MDF). The MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from various mixtures of hardwood fiber/dried OMS flour, 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (by weight) percents, respectively. With increasing OMS flour content, the flexural properties of the panels, modulus of rupture and modulus of elasticity, decreased by 31.0% and 29.2% as compared to panels without OMS flour, respectively. However, the water resistance was improved by the addition of the OMS flour up to 20 wt % content. For example, the thickness swelling and water absorption values of the panels containing 20% OMS flour were 17.3% and 59.5%, while they were found for the panels without OMS flour as 21.5% and 75.6%, respectively. The findings obtained in the study showed that the OMS was capable of serving as lignocellulosic raw material in the manufacture of the MDF. PDF
Experimental laminated veneer lumbers (LVLs) from rotary peeled I-214 (Populus x Euramericana) and two Populus deltoides I-77/51andS.307-26 fast growing hybrid poplar clones were manufactured with a melamine urea formaldehyde (MUF) adhesive successfully. Two Populus deltoides clones that are grown in Turkey were used for the first time in LVLs manufacturing. The results showed that clone types affected physical and mechanical properties of LVLs. Populus deltoides clones had better physical and mechanical properties compared to Populus x Euramericana clonedue to their higher density and fiber length values. S.307-26 clone had the highest and I-214 had the lowest properties among three hybrid poplar clones. The physical and mechanical properties of LVLs were higher than those of solid woods. This increase may be due to compaction factor (densification), manufacturing techniques, and the use of adhesives. The degree of contribution of solid wood properties to the LVLs’ properties was explained by using a contribution factor. Two Populus deltoides clones were found to be more suitable for LVLs manufacturing compared to Populus x Euramericana clone. PDF
In the present study, classical statistical tool Response Surface Methodology (RSM) was adopted for the optimization of process variables in the bioconversion of pretreated sugarcane bagasse into ethanol by cellulase and Candida wickerhamii MTCC 3013 based on Central Composite Design (CCD) experiments. A 23 five level CCD with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (25 – 45°) X1, pH (5.0 – 7.0) X2,and fermentation time (24 – 120 h) X3. Data obtained from RSM on ethanol production were subjected to analysis of variance (ANOVA) and analyzed using a second-order polynomial equation, and isoresponse contour plots were used to study the interactions among three relevant variables. Maximum response for ethanol production was obtained when applying the optimum values for temperature (33°C), pH (5.7), and fermentation time (104 h). Maximum ethanol concentration (4.28 g/l) was obtained from 50 g/l pretreated sugarcane bagasse at the optimized process conditions in aerobic batch fermentation. Various kinetic models such as Modified Logistic model, Modified Logistic incorporated Leudeking – Piret model, and Modified Logistic incorporated Modified Leudeking – Piret model were evaluated and the constants were predicted. PDF
Sodium titanate nanobelt was synthesized by treating titanium dioxide hydrothermally in concentrated sodium hydroxide solution. The product was characterized by SEM analysis and zeta potential measurement. It served as a microparticle to constitute a microparticle retention system with cationic polyacrylamide (CPAM), while the microparticle system was employed to induce the flocculation of kaolin clay. The flocculation behavior of kaolin clay in such a system was investigated by using a photometric dispersion analyzer connected with a dynamic drainage jar. It was found that the sodium titanate nanobelt carried negative charges and had a lower zeta potential at higher pH. It gave a large synergistic flocculation effect with CPAM at a very low dosage, and showed higher flocculation effect with CPAM under neutral and weak alkaline conditions. A suitably high shear level was helpful for the re-flocculation of clay by sodium titanate nanobelt. The clay flocculation induced by CPAM/titanate nanobelt system demonstrated high shear resistance and also generated dense flocs. PDF
The aim of this study was to evaluate effects of chemical pretreatment and storage on non-wood pulping and on pulp quality. The processes studied were hot water treatment followed by alkaline peroxide bleaching or soda cooking. The results showed that it is possible to store wheat straw outside for at least one year without significant changes in the raw material chemical composition and without adverse effects on the resulting pulp quality. The results are significant to the industry using non-woods to ensure the availability and the quality of the raw-material throughout the year in spite of the short harvesting time. PDF
Pitch-related deposition has been a significant issue in paper mills that produce wood-containing paper grades. A component analysis showed that a mill deposit sample was a mixture of wood resin, fiber, metal cations, and other inorganics. Based on the differential scanning calorimeter (DSC) method, some critical parameters, including pH, metal cations, and their interactions, on the thermal stability of pitch-related deposits were studied. The valency of metal cations determined the ability of capturing pitch the formation of deposits. Trivalent Al3+ or Fe3+ ions had much stronger effects than divalent Ca2+, Mg2+, or Mn2+. It was also found that a higher pH and trivalent Al3+ or Fe3+ increased the thermal stability of deposits formed in colloidal pitch solutions. PDF
Changes in the chemical structure of hornbeam and uludag fir woods during thermal treatment were investigated at three temperatures (170, 190, and 210 oC) and three durations (4, 8, and 12 hours). After thermal treatment, the extents of degradation in the chemical structure of the samples were determined, and the effects on the chemical composition of hornbeam wood and uludag fir wood were investigated. The data obtained were analyzed using variance analysis, and Tukey’s test was used to determine the changes in the chemical structure of uludag fir and hornbeam woods. The results showed that heating wood permanently changes several of its chemical structures and that the changes are mainly caused by thermal degradation of wood polymers. It was found that decreasing of the cellulose and holocelluloses ratio had a favorable effect on the interaction of the wood with moisture. According to the obtained results, hornbeam wood is affected more than uludag fir wood. For each wood, the maximum decreases of holocellulose and α-cellulose were found at 210oC for 12 hours, and the maximum increase of lignin occurred at the same treatment combination. PDF
A centrifugal method has been modified and applied to the assessment of water retention value (WRV) in cellulosic materials. Microcrystalline cellulose (MCC), small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller MCC particles/fibrils retained more water than the as-received MCC and pulp fibers. The results are useful for WRV measurements of cellulosic materials, especially for microfibrillated cellulose and small cellulosic fibrils. PDF
Baty, J. W., Maitland, C. L., Minter, W., Hubbe, M. A., and Jordan-Mowery, S. K. (2010). "Deacidification for the conservation and preservation of paper-based works: A review," BioRes. 5(3), 1955-2023.
Embrittlement threatens the useful lifetime of books, maps, manuscripts, and works of art on paper during storage, circulation, and display in libraries, museums, and archives. Past studies have traced much of the embrittlement to the Brønsted-acidic conditions under which printing papers have been made, especially during the period between the mid 1800s to about 1990. This article reviews measures that conservators and collection managers have taken to reduce the acidity of books and other paper-based materials, thereby decreasing the rates of acid-catalyzed hydrolysis and other changes leading to embrittlement. Technical challenges include the selection of an alkaline additive, selecting and implementing a way to distribute this alkaline substance uniformly in the sheet and bound volumes, avoiding excessively high pH conditions, minimizing the rate of loss of physical properties such as resistance to folding, and avoiding any conditions that cause evident damage to the documents one is trying to preserve. Developers have achieved considerable progress, and modern librarians and researchers have many procedures from which to choose as a starting point for further developments. PDF