BioResources, Volume 5, Issue 4
NOTE: Each current issue of BioResources continues to build as new articles are approved.
Articles published in scholarly journals, such as this one, tend to be mainly addressed to researchers at universities. Industrial follow-up and implementation of results from a scholarly article appears to be the exception, rather than the rule. Research grant specifications, as well as university policies, favor the generation of new knowledge, rather than the implementation of good ideas. But without patent protection, corporations have low motivation to expend the considerable effort to reduce ideas to practice after they have been openly published. The author speculates that the situation could be much more dynamic if there were a system of priority of implementation. According to such a system, the first company to successfully implement an idea that first appears in a peer-reviewed journal article, as validated by its debut in the marketplace, would have a grace period during which competitors would have to pay them a fee to sell a generic version of the same thing. PDF
Carbon footprint reduction is a global concern. For the papermaking industry, strategically effective measures of carbon footprint reduction can include many aspects such as energy efficiency improvement, use of renewable carbon-neutral energy, practicing of sustainable forestry, and development of an integrated forest products biorefinery. Filler addition in papermaking can save substantial amounts of pulp fibers, and reduce energy consumption, which can surely contribute to reduction in paper’s carbon footprint. However, the negative effect of filler addition on paper recycling, and the energy consumption associated with the production, processing, and treatment of fillers, will contribute to the carbon footprint. On balance, it can be considered that filler addition in reasonable amounts is likely to lower the paper’s carbon footprint. Certain research work is still needed to better understand the relationship between filler addition and the carbon footprint of papermaking. PDF
A convenient and efficient application of heterogeneous La-containing SBA-15 systems for the microwave assisted oxidation of a lignin model phenolic monomer, 4-hydroxy-1-phenylpropane, is reported. Low-cost and environmentally friendly H2O2 was used as the oxygen atom donor. The catalyst was prepared by immobilizing lanthanum species on the periodic mesoporous channels of siliceous SBA-15. Powder X-ray diffraction data and ICP-AES revealed that the host retains its hexagonal mesoporous structure after immobilization and most of the lanthanum species are better dispersed in the calcined materials. The surface area and pore size of La/SBA-15 was considerably decreased, indicating the intrapore confinement of the Lanthanum species. The activity of the La/SBA-15 was investigated in the oxidation of 4-hydroxy-1-phenylpropane in the presence of hydrogen peroxide as oxidant. 70.5% conversion of 4-hydroxy-1-phenylpropane was obtained after 30 min of reaction under 200W microwave irradiation, compared to a poor 28.1% degradation after 24h under conventional heating. The possibility of recycling the catalyst was studied. PDF
Electroless nickel deposition was carried out on Fraxinus mandshurica veneers for EMI shielding under a new activation process. In the process, Pd(II) was absorb ed on the surface of veneers modified with γ-aminopropyltrihydroxysilane (APTHS) obtained from the hydrolysis of γ-aminopropyltriethoxysilane (APTES). After the reduction, electroless plating was successfully initiated, and Ni-P coating was deposited on the veneers. The activation process and resulting coating were characterized by XPS, SEM-EDS, and XRD. The metal deposition, surface resistivity, and electromagnetic shielding effectiveness were measured. XPS analysis proved that Pd(II) was bonded to the amino group of APTHS and reduced to Pd(0). The coating was continuous, uniform, and compact. It consisted of 97.4 wt% nickel and 2.6 wt% phosphorus. XRD analysis showed that the coating was crystalline, which was related to the low phosphorus content. The plated Fraxinus mandshurica veneers exhibit good electro-conductivity with surface resistivity of 0.21Ω·cm-2 and higher electromagnetic shielding effectiveness of over 50dB in frequencies from 10 MHz to 1.5 GHz. PDF
Pyrolysis characteristics of corn stalk hemicellulose were investigated in a tubular reactor at different temperatures, with focus mainly on the releasing profiles and forming behaviors of pyrolysis products (gas, char, and tar). The products obtained were further identified using various approaches (including GC, SEM, and GC-MS) to understand the influence of temperature on product properties and compositions. It was found that the devolatilization of hemicellulose mainly occurred at low temperatures (<500°C), and produced large amounts of tar. A higher reactor temperature was conducive to the yield of gas products, accompanied by a reduction of tar because of the secondary cracking of volatiles. The gas components mainly consisted of CO2, CO, H2, and CH4, together with trace C2H4 and C2H6. The CO2 evolved easily and reached a relatively large yield of 129.2ml/g at 550°C, while CO and H2 were mainly released at higher temperatures (700-900°C). The tar was mainly composed of a range of oxygenated compounds, including ketones, furans, carboxylic acids, and alcohols, and their contents were influenced by the final temperature. An in-depth analysis of the properties of the products generated at different temperatures is favorable for a better understanding of the mechanism of hemicellulose pyrolysis. PDF
Krongtaew, C., Messner, K., Ters, T., and Fackler, K. (2010). "Characterization of key parameters for biotechnological lignocellulose conversion assessed by FT-NIR spectroscopy. Part 1. Qualitative analysis of pretreated straw," BioRes. 5(4), 2063-2080.
Wheat straw (Triticum aestivum L.) and oat straw (Avena sativa L.) were subjected to acid and alkaline pre-treatments partly in combination with hydrogen peroxide. The aim was to remove lignin and increase the accessibility of the polysaccharides to enzymatic digestion. Accessibility was evaluated by digestion with a cell wall degrading enzyme complex to yield reducing sugars that may serve as precursor substrates for biofuels or building block chemicals. Changes in lignin, hemicelluloses, as well as amorphous, semi-crystalline, and crystalline regions of cellulose moieties of pretreated straw were efficiently characterized by Fourier transform near-infrared (FT-NIR) reflectance spectroscopy. These alterations of the chemical structure of straw after different pre-treatment methods were powerfully differentiated by principal component analysis (PCA). Characteristics of the different samples owing to the different pre-treatment methods could be clustered from the PCA loadings spectra. PDF
Krongtaew, C., Messner, K., Ters, T., and Fackler, K. (2010). "Characterization of key parameters for biotechnological lignocellulose conversion assessed by FT-NIR spectroscopy. Part 2. Quantitative analysis by partial least squares regression," BioRes. 5(4), 2081-2096.
Wheat straw (Triticum aestivum L.) and oat straw (Avena sativa L.) were chemically pretreated at different severities with the purpose of delignification, which in turn leads to a better accessibility of plant cell wall polysaccharides for further biotechnological conversion. Key parameters of these samples, i.e. weight loss, residual lignin content, and hydrolysable sugars serving as precursors for biofuel production were monitored by wet-chemistry analyses. Fourier transform near infrared (FT-NIR) spectra were correlated to these data by means of partial least-squares (PLS) regression. Weight loss (4.0 – 33.5%) of the wheat straw could be predicted (RMSEP = 3.5%, R²test = 0.75) from the entire FT-NIR spectra (10000 – 4000 cm-1). Residual lignin content (7.9 – 20.7%, RMSEP = 0.9%, R²test = 0.94) and amount of reducing sugars based on pretreated wheat straw (128 – 1000 mg g-1, RMSEP = 83 mg g-1, R²test = 0.89) were powerfully evaluated between 6900 and 5510 cm-1, a spectral region where polysaccharides and lignin absorb. All these parameters could be equally predicted with even higher accuracy from pre-treated oat straw samples. Furthermore, some important parameters for anaerobic conversion of wheat straw to biogas – biogas production, total solids, and volatile solids content – could be estimated. PDF
Shibata, S., Bozlur, R. M., Fukumoto, I., and Kanda, Y. (2010). "Effects of injection temperature on mechanical properties of bagasse/polypropylene injection molding composites," BioRes. 5(4), 2097-2111.
Effects of injection temperature on thermal degradation and porosity of the bagasse/polypropylene injection molding composites were studied. Above 185 ºC, incomplete filling occurred. The incomplete filling increased with increase of injection temperature. It was found that the gas generated by thermal degradation of bagasse fibers was so accumulated in the injection cylinder that the injected composites ended up with incomplete filling. A modified injection method with the venting of gas increased the complete filling percentage. Mechanical properties decreased with increase of injection temperature from 165 ºC to 260 ºC. This was due to increase of porosity and fiber shortening. The calculated flexural modulus, which incorporated the effect of porosity and fiber length, agreed well with the experimental results. Composites with maleic acid anhydride grafted polypropylene (MAPP) were also investigated. Flexural strength and impact strength were improved by 45% and 35%, respectively, by addition of 20wt% MAPP. In the MAPP composites, fiber breakages at their roots were observed in the fracture surface after an impact test, while pulled-off fibers were observed in those without MAPP. PDF
This study sought to determine the suitability of fractionation and consequence-selective processing (separation of long fiber and short fiber, beating long fiber, and remixing with short fiber to target freeness) as a new approach to use of kenaf whole stem pulp for paper and paper-board production. A laboratory Bauer-McNett Classifier with screen 18 mesh was used to separate short fibers and long fibers of the unbeaten kenaf whole stem soda-anthraquinone high kappa and low kappa pulps. For comparison, the initial unbeaten pulps were beaten in the PFI mill to the same freeness (300 mL CSF). Results of our patented method showed that the fractionation process was able to provide a good opportunity to beat the long fiber portion at higher PFI revolutions and to achieve better fibrillation, significantly improving all paper properties of kenaf pulps except for tear index and producing sheets with better drainage and strength properties compared to conventionally beaten pulps, especially in the case of kenaf high kappa pulp. PDF
Dutt, D., Upadhyaya, J. S., and Tyagi, C. H. (2010). "Studies on Hibiscus cannabinus, Hibiscus sabdariffa, and Cannabinus sativa pulp to be a substitute for softwood pulp - Part 1: AS-AQ delignification process," BioRes 5(4), 2123-2136.
Hibiscus cannabinus, Hibiscus sabdariffa, and Cannabinus sativa, which are renewable non-woody fiber resources having characteristics similar to that of softwood (bast fibers), when used together with hardwood (core fibers), gave higher pulp yield with good mechanical strength properties when using an alkaline sulphite-anthraquinone (AS-AQ) pulping process rather than a conventional kraft pulping process and bleached more readily than kraft and soda pulps with a CEHH bleaching sequence. A comparison of properties AS-AQ pulping processes with soda and kraft pulping processes of H. cannabinus, C. sativa, and H. sabdariffa was made. All the properties were found to be better than soda and kraft pulps except tear index. All of the mechanical strength properties of handsheets of AS-AQ pulp improved except tear index. Therefore, the AS-AQ pulping process can be considered as ideal for manufacturing of paper grades like greaseproof, glassine, and high-quality writing and printing paper. PDF
Dutt, D., Upadhyaya, J. S., and Tyagi, C. H. (2010). "Studies on Hibiscus cannabinus, Hibiscus sabdariffa, and Cannabinus sativa pulp to be a substitute for softwood pulp - Part 2: SAS-AQ and NSSC-AQ delignification processes," BioRes 5(4), 2137-2152.
Hibiscus cannabinus, Cannabis sativa, and Hibiscus sabdariffa, fast growing productive annual plants, could provide fiber necessary to partially alleviate the world’s fiber deficit. The present study aimed at producing high yield pulp and the best mechanical strength properties with minimum impact on environment by SAS-AQ, and NSSC-AQ pulping processes. A total alkali of 13% (as Na2O), an alkali ratio of 0.80, and a Na2SO3 charge 11.70% (as Na2O) were found optimum to reduce maximum kappa number. A lower kappa number and good strength properties were achieved by increasing total alkali and Na2SO3 charge. SAS-AQ pulps showed good response towards CEHH bleaching. The NSSC-AQ pulping was conducted at a total alkali charge of 8% (as Na2O) by varying the ratio of sulphite-to-carbonate (100:0-0:100), and cooking time (60-120 min) at 1600C. A ratio of sulphite-to-carbonate 60:40 was suitable for corrugating medium (cooking time 60 min), while a ratio of sulphite-to-carbonate 70:30 showed better strength properties (longer cooking time). PDF
Removal of detrimental contaminants from paper machine circulation waters is known to benefit process runnability and paper quality. The applicability of selective flotation to remove substances of a hydrophobic nature from paper machine circulation waters was investigated in laboratory-scale experiments. The separation efficiency of ink, stickies, and wood extractives was studied by using a flotation scheme in which the froth was generated by the white water’s inherent surface active components without any chemical addition. The removal efficiency of detrimental contaminants was considered in relation to total losses of solid materials. The results showed that while not all white waters were able to produce stabile froth, those that generated froth also exhibited substantial separation of contaminants in the froth. With a moderate removal of 10% of total solids from white waters, removal of 45% of stickies, 27% of ink, and 20 to 50% of wood extractives was observed. Higher removal of contaminants resulted in solids losses at levels that are not economically feasible in paper production. The results showed that selective white water flotation can have beneficial results for papermaking processes. PDF
By removing the primary fines from an oxygen-delignified mill birch pulp, a fiber fraction was obtained having low metals content and no extractives. After DEDeD bleaching the fiber fraction had somewhat higher brightness and better brightness stability than the birch pulp containing the primary fines. The fines fraction was enriched with lignin, extractives, xylan, and metals. Bleaching the fines fraction in a QQP sequence did not affect the extractives, whereas a ZeQP sequence clearly reduced the extractives content. In a biorefinery concept, the fines fraction could be utilized as a source of xylan, fatty acids, sterols, and betulinol. Another possibility is to use the fines fraction unbleached or separately bleached as a bonding material in various fiber furnishes. PDF
A pyrolysis tube furnace system was designed to assess the impact of different components on pyrolysis characteristics under nitrogen atmosphere, and pyrolysis temperature (400 to 900oC) as important factors acting on the samples during pyrolysis. The obtained pyrolysate was classified into three groups, i.e. the condensed liquid product (bio-oil), solid product (bio-char), and light gas. Gas chromatography (GC) was used to analyze ingredients of the light gas released during pyrolysis, and a gas chromatography/mass spectrometer (GC/MS) was used to analyze bio-oil. The results revealed that the volatiles from rice straw pyrolysis exceeded that from lignin at temperatures below 700oC as a result of the higher char generation from lignin pyrolysis. With an increase of pyrolysis temperature, the yield of char decreased and light gas persistently increased, and the yield of bio-tar was maximized at 500oC. In the gas product, H2, CO, CO2 and some light hydrocarbons (CH4, C2H4 and C2H6) could be found, and H2 and CO were abundant. Compounds of bio-oil derived from lignin were simple and consisted of aromatic hydrocarbons, chain hydrocarbon, monoaromatics, and a minor amount of ketones. Phenolic compounds, which comprised 50 to 60%, can be converted easily to obtain high-value chemicals and high quality biofuels. PDF
Gu, R., Kokta, B. V., Frankenfeld, K., and Schlufter, K. (2010). "Bacterial cellulose reinforced thermoplastic composites: Preliminary evaluation of fabrication and performance," BioRes. 5(4), 2195-2207.
Mechanical properties of polyethylene (PE) composites were evaluated as a function of the addition of bacterial cellulose (BC). It was found that BC could improve the mechanical properties of the composites with or without the combination of traditional wood fiber. The improvements were affected by post-treatment. It was confirmed that BC had a significant influence on impact strength. The pellicle form of BC was able to achieve superior impact strength compared to the fluffy form of BC, but had similar effects on the tensile strength in comparison to the composites with fluffy BC. PDF
Attiogbe, F. K., Bose, S. K., Wang, W., McNeillie, A., and Francis, R. C. (2010). "The peroxymonocarbonate anions as pulp bleaching agents. Part 1. Results with lignin model compounds and chemical pulps," BioRes. 5(4), 2208-2220.
The peroxymonocarbonate mono-anion (HCO4─) is generated when the bicarbonate anion is added to a H2O2 solution. The mono-anion is believed to have a pKa value of ca. 10 and as such would start dissociating to the di-anion (CO42─) at pH ca. 8. The mono-anion should demonstrate electrophilic properties, while the di-anion should be a nucleophile. In an alkaline, non-sulfur pulping process such as soda/AQ, Na2CO3 could be obtained from the chemical recovery system and carbonated with CO2 from a flue gas stream to produce NaHCO3. In such a case only H2O2 would need to be purchased to generate the peroxymonocarbonate (PMC) anions. Bicarbonate anions could also be produced from the carbonation of solutions containing NaOH, Mg(OH)2 or mined Na2CO3. One or both of the PMC anions was found to be effective in oxidizing two lignin model compounds as well as lowering the lignin content of kraft and soda/AQ hardwood pulps. The PMC anions were generated in-situ by NaHCO3 or Na2CO3 + CO2 addition to dilute H2O2 solutions. PDF
Attiogbe, F. K., Wang, W., McNeillie, A., and Francis, R. C. (2010). "The peroxymonocarbonate anions as pulp bleaching agents. Part 2. Mechanical pulp brightening and effects of metal ions," BioRes. 5(4), 2208-2220.
The peroxymonocarbonate mono-anion (HCO4─) is generated in solutions containing bicarbonate anions (HCO3─) and hydrogen peroxide (H2O2). The mono-anion is believed to have a pKa value of ca. 10 and as such would start dissociating to the di-anion (CO42─) at pH ca. 8. The mono-anion should demonstrate electrophilic properties, while the di-anion should be a nucleophile. Results that appear to be due to electrophilic reactions of HCO4─ were presented in Part 1 of this series for lignin model compounds (LMCs) and chemical pulps. Some evidence was also observed for nucleophilic reactions with LMCs in the pH range of 8.8 to 9.5. Results are now being presented for mechanical pulp brightening, where nucleophilic reactions were observed. Hydrogen peroxide decomposition in the HCO3─ solutions was significant on some occasions, and Fe catalyzed decomposition was the most significant contributor in both pulp slurries and pulp-free solutions. PDF
The aim of this study was to investigate the effect of esterification via acetic or propionic anhydride on the surface roughness of eastern cottonwood. Eastern cottonwood (Populous deltoides) was esterified by using acetic or propionic anhydride without using any solvent or catalyst under different conditions. Two different weight percentage gains (WPGs) were obtained for each of the modifying chemicals. Three main surface roughness parameters, namely average roughness (Ra), mean peak to valley height (Rz) and maximum roughess (Rmax) were measured by a stylus method before and after esterification. The surface roughness was significantly increased due to the esterifications. The surface roughness of wood increased with increasing WPG. PDF
It is difficult to use lignin in any analytical methodology without reducing its considerable polydispersity by fractionation. An ammonium lignosulphonate sample was fractionated using a method of partial solubility in solutions of isopropanol increasingly diluted with distilled water, effectively fractionating by polarity. Selected fractions were characterised by gravimetric determination of the fractions, and determination of acid insoluble lignin, soluble lignin, and carbohydrate contents. Acid-insoluble lignin content was very low, and soluble lignin provided the majority of the lignin content, as should be expected from sulphonated lignin. Carbohydrate contents were also fairly low, the highest percentage at 14.5 being in Fraction 2, with the bulk lignin and Fraction 3 having 6.5% and 3.2%, respectively. Differences in the composition of each fraction support the efficacy of the fractionation process and permitted selection of fractions for use in subsequent studies. PDF
Nickel-based activated carbon was prepared from coconut shell activated carbon by electroless plating with palladium-free activation. The materials were characterized by scanning electron microscopy (SEM), X-ray energy dispersion spectroscopy (EDS), vibrating sample magnetometry (VSM), and vector network analyzer, respectively. The results show that the surface of the activated carbon was covered by a Ni-P coating, which was uniform, compact, and continuous and had an obvious metallic sheen. The content of P and Ni was 2.73% and 97.27% in the coating. Compared with the untreated activated carbon, the real permeability μ′ and imaginary permeability μ″ of Ni-based activated carbon became greater, whereas the real permittivity ε′ and imaginary permittivity ε″ became smaller. Also, the plated activated carbon was magnetic, making it suitable for some special applications. In general, the method reported here might be a feasible procedure to coat activated carbon with other magnetic metals, which may find application in various areas. PDF
Ghasemi, S., Eshkiki, R. B., Fatehi, P., and Ni, Y. (2010). "Impact of acid washing and chelation on Mg(OH)2-based hydrogen peroxide bleaching of mixed hardwoods CMP at high consistency," BioRes. 5(4), 2258-2267.
The removal of transition metal ions is crucial for improving the efficiency of subsequent peroxide bleaching. Acid-washing and chelation have been proposed for such a purpose. However, their influences on the Mg(OH)2-based peroxide bleaching of hardwood pulps at a high consistency have not been well documented in the literature. In this work, we studied the influence of acid-washing using sulfuric acid or chelation using diethylenetriaminepentaacetic (DTPA) on the Mg(OH)2- or NaOH-based hydrogen peroxide bleaching efficiency, effluent properties of bleaching filtrates, and paper properties. The results showed that for Mg(OH)2-based peroxide bleaching, the pulp yield and water retention value of acid-washed pulp were higher than those of the chelated pulp; the chemical oxygen demand (COD) and turbidity of the bleaching filtrates for the acid-washed pulp were lower than those of the chelated pulp. The bleached acid-washed pulp had lower strength properties than bleached chelated pulp did. Additionally, at a high pulp consistency (25%), the Mg(OH)2-based process had a higher bleaching efficiency and superior bleaching effluent properties, but a lower strength properties, in comparison with the NaOH-based process. PDF
The chemical composition of rice hulls produced in an artisan mill and its conversion to fermentable sugars was investigated. The carbohydrate fraction represented 59.2% (w/w) of the dry hulls. Cellulose, with 36.6%, was the main component, followed by xylan with 13.9%. An important contribution of starch (8.7%) was also detected. The content of ash (19.6%) and lignin (15.5%) was comparable with that of rice hulls obtained in industrial mills. Dilute-sulphuric acid hydrolysis at different temperatures, from 160 to 210°C, was evaluated for production of fermentable sugars. Due to starch hydrolysis, the concentration of glucose in the hydrolysates produced at 160°C was higher than the values that have previously been reported for industrial sorts of rice hulls under comparable conditions. The xylan-to-xylose conversion increased steadily with increase of the temperature and reached a maximum (67.7%) at 190°C. Further increases of the hydrolysis temperature decreased the yield of sugars due to their dehydration to furfural and HMF. PDF
Khalil, H. P. S. A., Bhat, I.-u.-H., and Sartika, M. Y. (2010). "Degradation, mechanico-physical, and morphological properties of empty fruit bunch reinforced polyester composites," BioRes. 5(4), 2278-2296.
This research aims to study the effects of degradation on mechanical, physical, and morphological properties of empty fruit bunch (EFB) fiber- reinforced polyester composites. The unsaturated polyester resin has been used to produce thermoset polymer composites. The reinforcing effect in composites was evaluated at various fiber loadings, including an overall fiber content (by weight) of 20% and 40%. The mechanical (tensile, flexural, and impact) and physical (density, moisture content, and water absorption) properties were studied before and after the samples were buried in the soil for period of 12 months. Scanning electron microscope (SEM) analysis was conducted to visualize the effect of the quality of adhesion between the fibers and matrix. The soil burial investigation results revealed that EFB fiber-polyester composites showed highest degradation percentage as compared to polyester resin and fiberglass. PDF
Ladeira, N. C., Peixoto, V. J., Penha, M. P., Barros, E. B. P., and Leite, S. G. F. (2010). "Optimization of 6-pentyl-alpha-pyrone production by solid state fermentation using sugarcane bagasse as residue," BioRes. 5(4), 2297-2306.
Solid state fermentation (SSF) has been used as a model for the study of metabolism and physiology of microorganisms. The aim of the present study was to enhance 6-PP production by Trichoderma harzianum 4040 in solid state fermentation using sugarcane bagasse as a residue. A fractional factorial design was used to select the components of the nutrient solution. The fermentation was carried out during 9 days, and the aroma extraction was done on the third, fifth, seventh, and ninth days using organic solvent. On the seventh day the major concentration of 6-PP was found. The variables glucose, sucrose, and MgSO4 were found to be significant statistically (p> 0.05) as components of the nutrient solution used in the production of 6-PP by filamentous fungi in SSF using sugarcane bagasse as a residue. GC-MS was used for quantification of 6-PP aroma. PDF
This paper presents the outcomes from an extensive investigation on the structure and geometry of single hemp fibres, as well as configurations and related tensile strength (TS) of hemp fibres, with the aid of field emission scanning and optical microscopy. The results showed that 1) the TS increased with the decrease of the diameter of individual test pieces, due possibly to the stacks of multiple single fibres within the test pieces; 2) shear failure between single fibres in a test pieces played a significant role in the test results; 3) the TS was closely related to the number of both the inherent joints along the fibre length and single fibres contained in the test pieces; 4) the splits along the length and width of hemp fibres may complicate the test results, and 5) the optimized treatment prior to decortications may double the TS of hemp fibres compared to a normal retting processing. Reliable TS of single hemp fibres have been derived by a power regression, and the predicted TS were verified with an excellent agreement with experimentally tested results. The tensile strain-stress plot was found to be linear for all hemp test pieces, showing that the behaviour of single hemp fibres obeys Hooke’s law. PDF
Polyethersulfone (PES) is a common material used for ultrafiltration (UF) membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose ﬁbrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils. PDF
This paper describes a method for the removal of acid-soluble lignin from acid-hydrolyzed hemicelluloses extracted from a mixture of northern US hardwood chips, by using Amberlite XAD-4 resin, which was shown to remove 100% of furan derivatives and 90% of acid-soluble lignin. Subsequent fermentation of the resin-treated hydrolyzates gave ethanol yields as high as 97% of theoretical and showed a marked increase in the fermentation rate. Regeneration of resin performed with 75% acetone was 85% efficient with respect to acid-soluble lignin. PDF
Polypyrrole (PPy) was chemically synthesised at two pH levels (pH = 2 and unadjusted pH, i.e. 6.6) using pre-formed carboxymethylcellulose-iron (CMC-Fe) complexes. The CMC-Fe complexes were prepared at a fixed CMC concentration, i.e. 5.5x10-5 mol/L, and with an increasing FeCl3 amount (from 4x10-3 to 5x10-2 mol/L). The quantity of iron bound to CMC was determined by the inductively coupled plasma (ICP-MS) method. In order to understand the interactions between CMC and iron, speciation of the systems was simulated by Phreeqc software. SEM analysis showed that, in some conditions (particularly at pH = 2), Py polymerised within the CMC-Fe complexes, forming particles with size ranging between 300 and 600 nm. In order to evaluate polymer electric conductivity, films were prepared by direct casting of the PPy-CMC-Fe dispersions with and without addition of film-forming CMC, and bulky PPy-CMC-Fe pellets were obtained by compression. Despite the different arrangement PPy-CMC-Fe particles in dry films, the amount of iron bound to CMC during the formation of CMC-Fe complexes was found to be the dominant parameter affecting polymer conductivity. PDF
Stajić, M., Kukavica, G., Vukojević, J., Simonić, J., Veljović-Jovanović, S., and Duletić-Laušević, S. (2010). "Wheat straw conversion by enzymatic system of Ganoderma lucidum," BioRes. 5(4), 2362-2373.
The purpose of this study was to resolve the question of whether various nitrogen sources and concentrations affect characteristics of selected G. lucidum ligninolytic enzymes participating in wheat straw fermentation. This is the first study reporting the presence of versatile peroxidase activity in crude extract of G. lucidum culture, as well as isoforms profile of Mn-oxidizing peroxidases. NH4NO3 was the optimum nitrogen source for laccase and Mn-dependent peroxidase activity, while peptone was the optimum one for versatile peroxidase activity. Four bands with laccase activity were obtained by native PAGE and IEF separations from medium enriched with inorganic nitrogen source, and only two bands from medium containing organic source. Medium composition was not shown to affect isoenzyme patterns of Mn-oxidizing peroxidases. Four isoforms of Mn-dependent peroxidase and three of versatile peroxidase were obtained on native PAGE. By IEF separation, five isoforms of Mn-dependent peroxidase and only two of versatile peroxidase were observed. The results demonstrated that G. lucidum has potential for mineralization and transformation of various agricultural residues and should take more significant participation in large-scale biotechnological processes. PDF
Many companies in the U.S. are entering the wood pellets market due to the increasing importance of woody biomass utilization for energy purposes. Despite a 200% increase in U.S. production, it is difficult to obtain reliable information from the research community relative to the production costs, requirements, and market trends for wood pellets. Based on comprehensive investigations, a techno-economical model for the determination of production costs for U.S. manufacturers (internal market, with sell strategy based on bagged product) was developed, considering the most important technical and financial factors that affect pellet production. Outcomes from a case-study show that pellet production is profitable for U.S. manufacturers and distributors/retailers, with more revenue margin for retailers. Sensitivity analyses were performed, showing that a pellet plant is especially sensitive to changes to the cost of biomass and labor. In addition, changes in energy and CAPEX also affect the NPV and IRR of the project, but not as significantly as biomass and labor costs. Additional findings indicate that increasing the plant size especially increases CAPEX, with labor being the least increased cost factor; in addition, production factors have to be closely monitored for small-scale producers, due to increases in operational costs. PDF
Date Palm Fiber (DPF) is one of the most available natural fibers in the Middle East, especially in Iran and the Persian Gulf region. This research provides a new insight into DPF, with consideration of morphological, chemical characteristics, and bulk density, as well as morphological and mechanical properties of DPF/HDPE wood plastic composite. There are three parts of date palm that are used for producing fiber, the trunk, rachis, and petiole. Results indicated that there is significant difference between trunk and petiole on fiber length but rachis has no significant differences relative to the other parts. The aspect ratios have significant differences among of three parts, with the highest and lowest values measured for the petiole and trunk, respectively. The chemical composition of various parts of the date palm tree differed significantly; with the highest amounts of cellulose and lignin content belong to rachis. Bulk density was measured for three parts of date palm, and the lowest amount was 0.082 g/cm3. The highest strengths were achieved in composites with 30 and 40% fiber content, depended on which original parts of the tree were used. PDF
Kurian, J. K., Minu, A. K., Banerji, A., and Kishore, V. V. N. (2010). "Bioconversion of hemicellulose hydrolysate of sweet sorghum bagasse to ethanol by using Pichia stipitis NCIM 3497 and Debaryomyces hansenii sp.," BioRes. 5(4), 2404-2416.
Production of ethanol from concentrated D-xylose solutions and hemicellulose hydrolysate of sweet sorghum bagasse was achieved by using Pichia stipitis NCIM 3497 and an isolated yeast Debaryomyces hansenii sp. These yeasts werecapable of producing ethanol from solutions containing 800 g/L D-xylose, and the optimum sugar concentration was found to be 150 g/L at pH 4, 30oC, with a production time of 72 hours. These yeasts were capable of utilizing multiple sugars. Hemicellulose hydrolysates of sweet sorghum bagasse were obtained by dilute acid hydrolysis and autohydrolysis including steam explosion treatment. The hydrolysate was treated by an over-liming process for detoxification and pH adjustment. Ethanol yield from hemicellulose hydrolysate was found to be higher than that of synthetic medium containing D-xylose. These yeasts can be used in production of ethanol from concentrated hemicellulose hydrolysates containing high pentose sugars obtained while treating lignocellulosic biomass at high substrate concentrations. PDF
The chemical properties and soda-ethanol pulping of Carpolobia lutea was investigated as an alternative raw material for pulp and paper production. The influence of temperature, time, and concentration of pulping liquor on the pulp yields and residual lignin contents was evaluated using a central composite design. The maximum variation in the minimum residual lignin content was caused by changes in time, while temperature and time were responsible for the variation in the highest pulp yield. A maximum pulp yield of 48.53% was obtained at low values of the process variables. The selectivity of lignin dissolution was independent of the working conditions but allowed quantitative estimations to be established between the yield and residual lignin content within the range studied. Combined effects of temperature and time revealed that pulping at high temperature for a short time may be more advantageous, especially when high rate of delignification and substantial savings in time is required. PDF
Zhong, L., Fu, S., Li, F., and Zhan, H. (2010). "Chlorine dioxide treatment of sisal fibre: Surface lignin and its influences on fibre surface characteristics and interfacial behaviour of sisal fibre/phenolic resin composites," BioRes. 5(4), 2431-2446.
This paper describes an investigation of the influences of chlorine dioxide treatment on fibre surface lignin. The fibre surface characteristics and the interfacial behaviour of the sisal fibre/phenolic resin composites were also studied by SEM, AFM, and XPS. The results show that the surface of the untreated fibre contains a large amount of lignin with granular structure and non-granular structure. The surface lignin concentration is up to 51% for the untreated fibre, and then it decreases to 24% and 20% for fibres treated with 1.5 % and 2.0% chlorine dioxide, respectively. The removal of lignin from the fibre surface can enhance the interfacial strength of the composites, giving rise to increases by 36% and 28% in tensile strength and internal bonding strength. These results indicate that the surface properties of single sisal fibres can be tailored to improve the fibre/resin interface. Chlorine dioxide treatment has potential for surface modification of sisal fibre in engineering the interfacial behaviour of composites. PDF
According to the character of straw pellet fuel cold molding technology, the compressing process was modeled by Finite Element Modeling (FEM) structure analysis tools. This indicated the variation laws between the stress and the strain, and the influence of the structure parameters of the die on the stress and the strain. It’s concluded from the work that when the length-to-diameter ratio of the die was 5.2 and the conicity of the die was 45o, the compress molding showed better degree of bonding and finish. This provided theoretical evidence for the study of the molding mechanism of the straw pellet and the selection of the structure parameters of the die. PDF
Mixtures of starch and lignocelluloses are available in many industrial, agricultural, and municipal wastes and residuals. In this work, dilute sulfuric acid was used for simultaneous pretreatment of lignocellulose and hydrolysis of starch, to obtain a maximum amount of fermentable sugar after enzymatic hydrolysis with cellulase and β-glucosidase. The acid treatment was carried out at 70-150°C with 0-1% (v/v) acid concentration and 5-15% (w/v) solids concentration for 0-40 minutes. Under the optimum conditions, obtained at 130°C, 1% acid, and 7.5% solids loading for 30 min, the starch was almost completely converted to glucose. However, the acid treatment was not successful for efficient hydrolysis of pure cellulose. A mixture of pine softwood and potato as representatives of lignocellulosic and starch components, respectively, were treated at the optimum conditions for acid hydrolysis of starch. The dilute-acid treatment resulted in 1.2, 60.5, and 23.6% hydrolysis of glucan, xylan, and mannan of pine wood and 67% of potato starch to fermentable sugars. After the acid treatment, the solid residue of the mixture was subjected to enzymatic hydrolysis. The enzymatic hydrolysis under the optimum conditions resulted in conversion of 76% of the glucan in the treated softwood. Therefore, using acid treatment of the mixture is a promising process for pretreatment of wood in addition to the hydrolysis of starch. PDF
Microbial biomass having 46% crude protein content and enriched with essential amino acids as well as extracellular xylanase activity (100-150 IU/ml) was produced by an efficient fungal strain, Penicillium janthinellum (NCIM St-F-3b). Optimization studies for maximum xylanase and biomass production showed that the fungus required a simple medium containing bagasse hemicellulose as carbon source and ammonium sulphate as the nitrogen source. Therefore bagasse, which is a waste product of the sugar industry, can be efficiently used in microbioal biomass protein preparation for animal feed. PDF
Esmeraldo, M. A., Barreto, A. C. H., Freitas, J. E. B., Fechine, P. B. A., Sombra, A. S. B., Corradini, E., Mele, G., Maffezzoli, A., and Massetto, S. E. (2010). "Dwarf-gren coconut fibers: A versatile natural renewable raw bioresource. Treatment, morphology, and physicochemical properties," BioRes. 5(4), 2478-2501.
Dwarf-green coconut fibers were modified by alkali treatment and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), as well as thermogravimetric (TGA), mechanical, and dielectric analyses. Changes in composition, structure, and morphology of the coconut fibers were observed after sodium hydroxide treatments due to the removal of lignin, hemicellulose, and other impurities. The XRD data were in agreement with the morphological analysis, where the crystallinity fraction increased with the concentration of alkali solution and fell off above 10%. The infrared spectrometry showed the partial dissolution of hemicellulose, lignin, and pectin, which was clearly identified by the band at 1736 cm-1. Thermogravimetric analysis showed a double degradation process for the untreated dwarf-green coconut fibers, while a single one was observed after the pretreatment. The tensile properties showed an increased elongation at break, modulus, and strength, and the dielectric results showed a decrease of all parameters (permittivity, dielectric loss, and conductivity), reflecting the reduced dipole and ion mobility associated with the loss of amorphous components. PDF
The effect of hemicellulose extraction of pine wood chips by water prehydrolysis on subsequent kraft cooking and paper properties was studied. Prehydrolysis reduced the required cooking time by approximately 40% and increased kappa number reduction in oxygen delignification. Prehydrolysis decreased the overall brownstock pulp yield on wood by 7.2 percentage units. Consequently, valuable products would need to be produced from the prehydrolyzate to compensate for the resulting increase in wood consumption. In DED-bleaching, lower bleaching chemical dosages were needed with prehydrolyzed than with unhydrolyzed pulps to obtain similar final brightness. As expected, removal of hemicelluloses led to a decrease in the tensile index and increase in the tear index. At a given density, the strength potential of prehydrolyzed pulps was higher than that of unhydrolyzed pulps. There was an up to more than fivefold increase in beating revolutions in a PFI-mill needed to obtain comparable tensile indices. This significant reduction in beating response might pose problems in the commercialization of prehydrolyzed pulps. In general, differences between the paper properties of prehydrolyzed pulps and unhydrolyzed pulps are attributed to decreased inter-fiber bonding in prehydrolyzed pulps. PDF
Current deinking processes use potentially environmentally damaging chemicals in large quantities. The use of enzymes could be an attractive alternative to certain other chemicals used in deinking. In this research, the effects of different HLB (hydrophile-lipophile balance) values and enzymatic treatments on the deinking of old newspaper pulp (ONP) was studied, and optical properties and mechanical strengths of deinked pulps (DIP) were determined. Enzymatic treatments of old newspaper pulps were performed at two temperatures, 20°C and 50°C. Nonionic surfactants with different HLB values were used as the flotation agent. The flotation was conducted for pulps with and without enzymatic treatment. The results showed that brightness values for the floated pulp without enzyme treatment were slightly greater than for the enzyme-treated deinked pulp. Also, dirt count for treated pulps with commercial cellulase and floated with ethoxylated fatty alcohol of HLB 12 at 50°C was lower than that of other pulps. The mechanical strengths of the enzymatically deinked pulps, in terms of burst, tensile, folding endurance, E-MOD, and elongation, were increased, but tear strength for the floated pulps with ethoxylated fatty alcohol of HLB 12 was increased at 50°C without enzymatic treatment. Also, the deinking efficiency of handsheets made from treated pulps with commercial cellulase and ethoxylated fatty alcohol of HLB 12 was highest. The treated pulps with enzyme only, with a combination of commercial cellulase and lipase at 50°C, showed the lowest freeness value in comparison with other pulps. PDF
Rodriguez, M., Rodrigues, A., Bayer R., J., Vilaseca, F., Girones, J., and Mutje, P. (2010). "Determination of corn stalk fibers' strength through modeling of the mechanical properties of its composites," BioRes. 5(4), 2535-2546.
Worldwide cultivation of corn is expanding, due in part to the increasing production of bioethanol. In consequence, huge amounts of corn stalks residues are been produced. Instead of incineration, we transformed the corn stalks into a semichemical pulp and successfully applied it as reinforcement in polypropylene composites. PP composites reinforced with 40% wt corn stalk single fibers were prepared, and their mechanical properties were evaluated. Through mechanical properties modeling of the composites, the intrinsic tensile strength of the cellulosic fibers that constitute the corn stalk have been determined. PDF
In order to develop novel polymeric supports based on cellulosics, cellulose extracted from pine needles, a perennial resource material available in huge quantities as waste, was graft copolymerized with vinyl monomers. Cellulose, cellulose derivatives, and their graft copolymers with highest percent grafting (Pg) were used as supports for immobilization of an industrially important protease enzyme and the protein bovine serum albumin (BSA) by a specific sorption method. The Manachini method was used to determine activity of the immobilized enzyme. Sorption of protein was characterized by activity of protein concentration by the Lowry method. Cellulose itself was found to be effective as a polymeric support to retain a good amount of protease and BSA, whereas cellulose derivatives were effective to adsorb BSA only. Among cellulose graft copolymers, those based on methyl methacrylate proved to be better sorbents. PDF
Cellulose nanofibers were isolated from kenaf core fibers by employing chemo-mechanical treatments. The morphologies and sizes of the fibers were explored with environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM). The results of chemical analysis showed that the cellulose contents of the bleached pulp fibers and nanofibers increased from 46% to 92% and to 94%, respectively. Most of the produced nanofibers had diameters in the range of 20 to 25 nm, whereas kenaf nanofibers ranged in diameter diameters from 10 to 75 nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the removal of lignin and the majority of the hemicelluloses from the kenaf core fibers. The thermogravimetric analysis (TGA), which was carried out to evaluate the thermal properties of the fibers, demonstrated that the thermal stabilities of these fibers were increased by the chemo-mechanical treatments. The results of X-ray analysis confirmed that chemical and mechanical treatments can improve the crystallinity of fibers. PDF
Loureiro, P. E. G., Domingues, E. F., Evtuguin, D. V., and Carvalhol, M. G., V. S. (2010). "ECF bleaching with a final hydrogen peroxide stage: Impact of the chemical composition of Eucalyptus globulus kraft pulp," BioRes. 5(4), 2567-2580.
Two industrial elemental chlorine free (ECF) bleaching sequences, D0(EOP)D1(EP)D2 and OQ(PO)DP, are compared with respect to the bulk content of lignin, carboxyl, hexeneuronic acids (HexA), and reducing groups after each bleaching stage. HexA groups contribute significantly to the total content of carboxyl groups, and their degradation during chlorine dioxide bleaching is reflected by a decrease of the carboxyl content. The higher degradation using an enhanced use of oxygen-based bleaching chemicals is associated with a higher fiber charge reduction, mainly due to xylan depletion. Additionally, the effect of process variables of a laboratory final hydrogen peroxide stage on the chemical composition of the fully bleached pulp (D0(EOP)D1P and OQ(PO)DP) is studied. The ability of final peroxide bleaching to raise the content of carboxyl groups is dependent on the operating conditions and pulp bleaching history. A balance between carbohydrate oxidation and dissolution of oxidized groups determines the effect on fiber charge. The effect of hydrogen peroxide stabilizers added into the final stage on the content of carboxyl groups is also reported. PDF
Urea-formaldehyde prepolymer and hot-press drying were used to improve the properties of poplar wood. The wood was impregnated with the prepolymer using a pulse-dipping machine. The impregnated timbers were compressed and dried by a multilayer hot-press drying kiln. The drying rate was more rapid during the chemical modification and hot-press drying than conventional kiln-drying. In addition, the properties of timber were also enhanced obviously. When the compression rate was 28.6%, the basic density, oven dry density and air-dried density of modified wood improved 22%, 71%, and 70%, respectively. The bending strength and compressive strength parallel to grain increased 60% and 40%. The water uptake of treated wood was significantly decreased compared with the untreated wood. The FTIR analysis successfully showed that the intensity of hydroxyl and carbonyl absorption peaks decreased significantly, which was attributed to a reaction of the NHCH2OH of urea-formaldehyde prepolymer with the wood carboxyl (C=O) and hydroxyl (-OH) groups. The XRD results indicated that the degree of crystallinity increased from 35.09% to 36.91%. The morphologic models of chemical within wood were discovered by SEM. PDF
González, D., Campos, A. R., Cunha, A. M., Santos, V., and Parajó, J. C. (2010). "Utilization of fibers obtained by peroxyformic acid processing of broom as reinforcing agents for biocomposites," BioRes. 5(4), 2591-2610.
Broom (Cytisus scoparius) samples were processed in media containing formic acid and hydrogen peroxide (MILOX process) to obtain cellulose-enriched solids. The chemical processing of broom samples was assessed by means of a centered, second order factorial design of experiments. Empirical models derived from the experimental data gave a close interpretation of the experimental patterns, and enabled the selection of operational conditions for achieving extensive delignification and hemicellulose removal, while minimizing the dissolution of cellulose. Broom samples processed under the selected conditions were employed to reinforce PLA composites, which were characterized mechanically and by DSC, SEM, and water absorption experiments. PDF
Hamdan, S., Rahman, M. R., Ahmed, A. S., Talib, Z. A., and Islam, M. S. (2010). "Influence of N,N-dimethylacetamid on the thermal and mechanical properties of polymeriflled wood," BioRes. 5(4), 2611-2624.
Mercerized wood species were impregnated with N, N-dimethylacetamid. The FT-IR showed enhanced absorption at 1419 cm-1(-C-/CH3), and the 1267 cm-1 (-N-/ CH3) stretching band confirmed the polymerization reaction. Differential scanning calorimetric analysis indicated that the decomposition temperature of WPC gives a higher thermal stability compared to the raw material. WPC yielded higher MOE and MOR compared to the untreated wood. The Young’s modulus of Xylopia Spp Artocarpus Rigidus and Eugenia Spp were significantly different between raw wood and WPC. The increase in the stiffness and the thermal stability of the composites increased due to the crystallinity of WPC as indicated by XRD analysis. PDF
The effect of hardwood admixture (15-25% birch or aspen) in kraft cooking on the strength properties of the fully bleached pulp was investigated. Results obtained from both lab- and mill-processed ECF bleached pulps showed that adding 15-25% birch or aspen to the production of fully bleached softwood kraft pulp had a minor effect on the strength properties. No significant effect was observed for the hardwood admixture on the apparent density over a wide range of breaking length. Under the conditions studied, the results showed that pulping of mixed softwood/hardwood chips (chip blending) resulted in overall better strength properties than the pulp blending at a given freeness. It was hypothesized that the softwood fibers would be cooked to a higher kappa number in the cooking of mixed softwood/hardwood chips for the same target kappa number, thus having higher fiber strength due to higher pulp viscosity and preservation of the hemicellulose. This was supported by the results from zero-span tensile strength of the long fiber fraction of the samples from chip blending and pulp blending. The implication is that some softwood kraft pulp mills can add up to 25% of hardwood chips to the kraft cooking of softwood chips without significantly affecting the overall pulp strength properties. PDF
Effects of temperature and press pressure on the anatomical structure of solid-wood panels produced by using Pinus sylvestris L. (Scotch pine) wood were evaluated. Solid wood panels with dimensions of 250 by 500 by 18 mm were hot-pressed using a laboratory hot press at a temperature of either 120°C or 150°C and pressure of either 5 or 7 MPa for 1 h. Microscopic investigations conducted by Light Microscopy (LM) and Scanning Electron Microscopy (SEM) showed that the highest deformation occurred in earlywood regions of all growth rings for each process condition and the distribution of deformation was not uniform in growth rings. Cell-wall thickness was observed to be an important factor in wood behavior during thermal compressing processes. The results showed clearly that the impact of pressure in wood structure is promoted by increased temperature. Significant densification was observed at the maximum temperature and maximum pressure condition employed in the study, and almost all earlywood layers showed cell collapse. The study revealed that a homogenous structure of growth rings with the uniform earlywood and latewood widths throughout the wood samples plays a major role in prevention of cell collapse. The results indicated that both process conditions and anatomical structure of the wood have an interaction. PDF
Feasibility of electrochemically generated biocides in papermaking was evaluated in pilot scale trials. The trials indicated that electrochemically generated biocides prevent microbial growth and proliferation in broke systems, as well as in water circulations. The spoilage of broke can be delayed, and already spoiled broke can be recovered using these biocides. The improved broke quality increases the stability of the paper machine and, consequently, less broke is produced. The biocides can be added to water or pulp, and they have hardly any negative effect on the process or the end product. The presence of reducing compounds may cause limitations in the use of these oxidative biocides. It was observed that electrochemically generated biocide was also efficient against heat-resistant spores. However, the biocide was less efficient against spores as compared to vegetative cells, both aerobic and anaerobic, especially when the spore numbers were higher than 104 cfu/ml. Onsite oxidant production eliminates the transportation and storage of biocides. Moreover, due to the short time between the production and use, the degradation of the active compounds can be minimized. PDF
This paper describes the development of a simple UV spectroscopic method for determination of silicon content in black liquor. The method is based on the fact that Si (IV) can react with ammonium molybdate to form Si-Mo heterophony acid in an acidic condition (pH=4). The absorption peak of α-Si-Mo heterophony acid is 340 nm. To avoid the compensation of the instrument, 360 nm is used for spectroscopic quantification. A certain time (20 min) for the reaction is necessary. Moreover, it was discovered that 480 nm could be used to develop a dual-wavelength method to account for the spectral interference from dissolved lignin in black liquor. This method is simple, rapid, sensitive, accurate, and has the potential for on-line applications. PDF
It was aimed in this study to determine the effect of the number of joints in frames produced from Oriented Strand Board (OSB) and of the type of adhesive on the diagonal tensile strength (DTS) of the frame. With this objective, a total of 152 specimens were prepared from OSB in accordance with the principles in the EN 2470 test standard. The diagonal tensile test was applied to the specimens in the universal test equipment in accordance with ASTM-D 1037. According to the statistical analysis of the data obtained from the tests, the number of dovetail joints and the type of adhesive had significant effects on the DTS. The highest DTS (0.117 N/mm2) was obtained in the specimens with a single dovetail joint and bonded with the PVAc adhesive. This alternative was followed by the specimens with a double dovetail joint bonded with the PVAc adhesive (0.078 N/mm2) and the specimens with a single dovetail joint bonded with the PU adhesive (0.073 N/mm2). The lowest DTS occurred in the specimens with single and double joints without adhesive. According to these results, adhesive should definitely be used in the corner joining of the dovetail joints, and the single dovetail joint joining type bonded with PVAc adhesive is preferred. PDF
Allix, J., Beneventi, D., Zeno, E., and Nortier, P. (2010). "Flotation de-inking of 50% ONP/ 50% OMG recovered papers mixtures using nonionic surfactant, soap, and surfactant/soap blends," BioRes. 5(4), 2702-2719.
A laboratory flotation column equipped with Venturi aerators and an adjustable froth removal system was used to study the effect of calcium soap and a mixture of calcium soap/alkyl phenol ethoxylate surfactant on ink and fibres transfer during flotation de-inking of a 50% old newprint (ONP) / 50% old magazines (OMG) recovered papers mixture. Mass transport phenomena determining the yield of the flotation process were interpreted using model equations describing particle removal in terms of flotation, entrainment, and drainage in the froth. A decrease in the ink and mineral fillers flotation rate constant, drainage through the froth, and in fibre entrainment was observed when increasing the surfactant concentration. These trends were consistent with the typical dispersing action of the studied nonionic surfactant. An opposite effect on ink and fillers was observed when using calcium soap alone, and the increase in the flotation rate constant and drainage through the froth were consistent with the collecting and defoaming action of the calcium soap. Moreover, fibre entrainment decreased when increasing the soap concentration. The study of the surfactant/soap mixture highlighted the absence of synergy between the calcium soap and the surfactant. PDF
A preliminary experimental study was carried out to examine the ability of a chemically modified Acacia spp. to resist biodegradation. The modifications of Acacia mangium and Acacia hybridwere carried out by propionic anhydride and succinic anhydride in the presence of sodium formate as a catalyst. The treated samples were found resistant to microbial attack, while the untreated ones were damaged on 12 months exposure to a soil burial. The appearance grading, mass loss, mechanical properties, and scanning electron microscopy results revealed that chemical modification enhances the resistance of Acacia mangium and Acacia hybrid wood species to biodegradation. PDF
Modified fillers consisting of kaolin particles encapsulated by starch have recently been demonstrated in mill trials to achieve significant filler loading levels without accompanying strength losses. In this work, laboratory experiments were conducted to explore the potential advantages of using starch-treated pigment for strength increases by application of surface coating. It is found that a platy clay coating will produce a higher increase in strength per unit weight of application compared to a fine clay, and more-so if the clay is encapsulated in starch. Starch encapsulation of clay produces a greater increase in strength than an equivalent weight proportion addition of starch to a kaolin formulation blend. The observations and measurements of changes in various physical properties of the coated samples are explained by a proportionate loss of void volume in the coating from the encapsulation process and the increase of stress transfer through introduction of higher platelet aspect ratio. PDF
Refining of bleached hardwood pulps and bleached softwood pulps having different counter-ions to the charged groups within the fibres was studied. The results show that an energy reduction of 50% for the hardwood pulps and 20% for the softwood pulp can be achieved if the fibres are converted into the Na+-form prior to refining. The results also show that the amount of charged groups in the fibres is important for the refinability, which explains why the refining efficiency is much lower for bleached softwood fibres, which have a much smaller amount of charged groups than the bleached hardwood pulp. PDF
Chitosan obtained by alkaline deacetylation of chitin is a non-toxic, biocompatible, and biodegradable natural polymer. Chitosan-based hydrogel polymeric beads have been extensively studied as micro- or nano-particulate carriers in the pharmaceutical and medical fields, where they have shown promise for drug delivery as a result of their controlled and sustained release properties, as well as biocompatibility with tissue and cells. To introduce desired properties and enlarge the scope of the potential applications of chitosan, graft copolymerization with natural or synthetic polymers on it has been carried out, and also, various chitosan derivatives have been utilized to form beads. The desired kinetics, duration, and rate of drug release up to therapeutical level from polymeric beads are limited by specific conditions such as beads material and their composition, bead preparation method, amount of drug loading, drug solubility, and drug polymer interaction. The present review summarizes most of the available reports about compositional and structural effects of chitosan-based hydrogel polymeric beads on swelling, drug loading, and releasing properties. From the studies reviewed it is concluded that chitosan-based hydrogel polymeric beads are promising drug delivery systems. PDF
Plant-derived cellulosic materials play a critical role when organic wastes are composted to produce a beneficial amendment for topsoil. This review article considers publications dealing with the science of composting, emphasizing ways in which the cellulosic and lignin components of the composted material influence both the process and the product. Cellulose has been described as a main source of energy to drive the biological transformations and the consequent temperature rise and chemical changes that are associated with composting. Lignin can be viewed as a main starting material for the formation of humus, the recalcitrant organic matter that provides the water-holding, ion exchange, and bulking capabilities that can contribute greatly to soil health and productivity. Lignocellulosic materials also contribute to air permeability, bulking, and water retention during the composting process. Critical variables for successful composting include the ratio of carbon to nitrogen, the nature of the cellulosic component, particle size, bed size and format, moisture, pH, aeration, temperature, and time. Composting can help to address solid waste problems and provides a sustainable way to enhance soil fertility. PDF