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Cotton wool, cotton textile, tissue paper and printing paper, all potential waste cellulosic materials, were directly converted to sorbitol using a Ru/CNT catalyst in the presence of H 2 and using only water as solvent, without any acids. Conversions up to 38% were attained for the raw substrates, with sorbitol yields below 10%. Ball-milling of the materials disrupted their crystallinity, allowing reaching 100% conversion of cotton wool, cotton textile and tissue paper after 4 h, with sorbitol yields around 50%. Mix-milling these materials with the catalyst greatly enhanced their conversion rate, and the materials were efficiently converted to sorbitol with a yield around 50% in 2 h. However, ball- and mix-milled printing paper presented a conversion of only 50% after 5 h, with sorbitol yields of 7%. Amounts of sorbitol of 0.525, 0.511 and 0.559 g could be obtained from 1 g of cotton wool, cotton textile and tissue paper, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Wood from the leguminous tree, Leucaena diversifolia, was subjected to hydrothermal treatment (autohydrolysis) at 160–180°C for 0–30min followed by ethanol–soda–anthraquinone delignification. The liquid phase contained 18.65g of sugars per liter, and the solid phase had a gross heating value of 19.083MJ/kg, but could also be used as a source of cellulose pulp for the production of paper with tear, burst, and tensile indexes of 2.4Nm2/kg, 2.6MPam2/kg and 40.7kNm/kg, respectively. L. diversifolia lends itself readily to valorization for energy production, and also to integral, fractional exploitation by autohydrolysis and ethanol–soda–anthraquinone delignification, which can additionally bring environmental benefits to cropping zones. [Copyright &y& Elsevier]

Abstract: The aim of this work was to chemically characterize orange tree prunings and use it in pulping and combustion processes. Soda-anthraquinone pulping of the main fraction of orange pruning (stems with a diameter >0.5cm) was simulated with polynomial and neurofuzzy models, that predicted pulp properties as a function of operating variables (155–185°C, 40–90min, soda concentration, 10–16%) with errors less than 20%. The heating values (16,870kJ/kg), the flame temperature (1150–2150°C) and dew point temperature of fuel gas (47–53°C) for the residual fraction from orange pruning (stems diameter <0.5cm and leaves) was determined and compared with other non-wood lignocellulosic materials. As a consequence the price of kJ obtained by combustion of this residual fraction is less than other lignocellulosic materials, much lower than those of fossil fuels. [Copyright &y& Elsevier]

Abstract: Chitosan–guanidine complexes were prepared by reacting chitosan and polyhexamethylene guanidine hydrochloride or crosslinked polyhexamethylene guanidine hydrochloride in the presence of sodium tripolyphosphate as a crosslinking agent. The complexes, used as functional additives for paper, synergistically improved wet-strength and antimicrobial activities. In comparison with the control sample, the wet/dry strength ratio of hand-sheets treated with the complexes was increased from 2.65% up to 23.3%. The MIC values of the chitosan–PHGH and chitosan–PHGHE complexes against Escherichia coli were 15.6 and 31.2μgmL−1, respectively, thus demonstrating excellent antimicrobial activity. Hand-sheets treated with the complexes exhibited antibacterial activity against E. coli and Staphylococcus aureus. The release of the guanidine polymers included in the complexes was dynamically monitored using UV and the results showed the amount released exceeded 80%. Atomic force microscopy images indicated that the antimicrobial mechanism of the complexes was likely due to membrane damage. [Copyright &y& Elsevier]

Abstract: Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. [Copyright &y& Elsevier]

Abstract: The influence of the hydrothermal treatment conditions of rice straw (temperature – 150–190°C , time – 0–20min after reaching the operation temperature – and liquid/solid ratio – 6–8), on the composition of liquid and solid fractions was studied. Polynomial models were found for to reproduce the experimental results with errors less than 6%. Operating to 190°C, 15min and 9 liquid/solid ratio was obtained high values of glucose (1.92g/L), xylose (3.97g/L), arabinose (0.99g/L) and acetic acid (1.96g/L), what allows to save capital when not operating with the maximum time and/or liquid/solid ratio; yield in the solid fraction is 88.1% and lignin content 24.43%. If what it is required to obtain good values of yield (96.46%) and lignin content, is necessary to operate to 150°C, obtaining lower concentrations glucose (1.11%), xylose (2.78%), arabinose (0.56%) and acetic acid (0.39%). Ethanolamine pulping of solid fraction of hydrothermal treatment provides pulp with higher or similar properties to those obtained of pulping rice straw with ethanolamine or soda. [Copyright &y& Elsevier]

This study was conducted to determine the characteristics and biogas production potential of organic materials separated from municipal solid wastes using a rotary drum reactor (RDR) process. Four different types of wastes were first pretreated with a commercial RDR system at different retention times (1, 2 and 3 d) and the organic fractions were tested with batch anaerobic digesters with 2.6gVSL−1 initial loading. The four types of waste were: municipal solid waste (MSW), a mixture of MSW and paper waste, a mixture of MSW and biosolids, and a mixture of paper and biosolids. After 20 d of thermophilic digestion (50±1°C), it was found that the biogas yields of the above materials were in the range of 457–557mLgVS−1 and the biogas contained 57.3–60.6% methane. The total solid and volatile solid reductions ranged from 50.2% to 65.0% and 51.8% to 66.8%, respectively. For each material, the change of retention time in the RDR from 1 to 3d did not show significant (α =0.05) influence on the biogas yields of the recovered organic materials. Further studies are needed to determine the minimum retention time requirements in the RDR system to achieve effective separation of organic from inorganic materials and produce suitable feedstock for anaerobic digesters. [Copyright &y& Elsevier]

Abstract: The influence of operational variables in the pulping of vine shoots by use of ethylene glycol [viz. temperature (155–185°C), cooking time (30–90min) and ethylene glycol concentration (50–70% v/v)] on the properties of the resulting pulp (viz. yield, kappa number and viscosity) and paper sheets (breaking length, stretch, burst index, tear index and brightness) was studied. A central composite factorial design was used in conjunction with the software ANFIS Edit Matlab 6.5 to develop fuzzy neural model that reproduced the experimental results of the dependent variables with errors less than 5%. The model is therefore effective with a view to simulating the ethylene glycol pulping process. [Copyright &y& Elsevier]

Waste gas containing diethyldisulphide (DEDS) is generated from various industries including pulp and paper, refinery, rayon and molasses based distilleries, etc. DEDS has odour threshold detection with an average concentration of 10−9 mg/m3 at 25°C. DEDS is toxic to bacteria, fungus and also to mammals when exposed for a long period. Waste gas containing DEDS require proper treatment prior to discharge into the environment. DEDS containing waste gas was treated in a biofilter, packed with compost along with wooden chips and enriched with DEDS degrading microorganisms. The biofilter could remove DEDS to the extent of 94±5% at a loading of 1.60g/m3/h with an empty bed retention time of 150s. At optimal operating conditions, the average moisture content required by the biofilter was in the range of 60–65%. The biodegradative products of DEDS were thiosulphate and sulphate. [Copyright &y& Elsevier]

This paper reports on the influence of independent variables in the pulping of holm oak wood [viz. temperature (135–195°C), cooking time (30–90min) and soda concentration (10–20%)] on the properties of the resulting paper sheets. By using a central composite factorial design and a fuzzy neural model, equations relating each dependent variable to the different independent variables were derived that reproduced the experimental results for the dependent variables with errors less than 14%. Using a soda concentration of 17.5% at 195°C for 30min, it is possible to reduce the working capital (cost of chemical) and the capital investment, because it is operated with smaller values of the soda concentration and cooking time that maximum considered (20% of soda concentration and 90min). The pulp yield thus obtained differed by less than 31.3% from the highest possible value; also, the resulting pulp and paper sheets had acceptable properties that differed by less than 21.10% from their optimum values. [Copyright &y& Elsevier]

In order to identify faster-growing non-woody species usable for biomass and paper production, four Leucaena species (L. diversifolia, L. colinsii, L. salvadorensis and three varieties of L. leucocephala) were tested. All the Leucaena species showed a good soil and climatic adaptation to Spain Southwest except for L. salvadorensis. Studied Leucaena species showed biomass productivity ranges from 67.14 to 9.44tha−1 (o.d.b.) and 43.6 to 11.4tha−1 under Mediterranean conditions for the first and second year sprouts, respectively. The quantity of solubles and extractives shows similar values when compared with wood materials. Relatively lower lignin content in Leucaena (from 15.7% to 21.4%) species has been found with respect to other vegetal species. The α-cellulose contents (39.4–45.3%) are in the range of the normal values expected for the other non-wood raw materials. The study confirms the feasibility of organocell yield pulping process to Leucaena species. Organocell process provides an efficient delignification (kappa number 12.4 and pulp yield 42.2%) for L. leucocephala and suitably physical characteristics of paper sheet (tensile index 20.3kNm/kg for L. diversifolia). [Copyright &y& Elsevier]

Abstract: In order to identify faster-growing non-woody species usable for biomass and paper production, four Tagasastes (Chamaecytisus proliferus) from different origins are tested. All the Tagasaste species (T. Huelva, T. Australia, T. New Zealand and T. La Palma island) show a good soil and climatic adaptation to Southwest Spain. The studied Tagasaste provenances shows biomass productivity ranges from 1.0tha−1 yr−1 to 3.4tha−1 yr−1 (o.d.b.) and 25.3tha−1 yr−1 to 49.4tha−1 yr−1 under Mediterranean conditions for first and second year sprouts, respectively. The quantity of solubles and extractives shows similar values when compared with wood materials. A relatively lower lignin content in Tagasaste (from 13.7% to 17.1%) species has been found with respect to other vegetal species. The α-celullose contents (43.6–45.3%) were in the range of the normal values expected for the other non-wood raw materials. The study confirms the feasibility of the organocell yield pulping process to Tagasaste provenances. Organocell processes provide an efficient delignification (kappa index from 7.2 to 10.9 and pulp yield from 43.6% to 54.1%). The best results are obtained for the physical properties of paper sheets for Tagasaste from Australia in the second year, with values of tensile index of 16.0kNm/kg, burst index of 1.12MPam2/kg and tear index of 0.55Nm2/kg. [Copyright &y& Elsevier]

Abstract: Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, α-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170°C and 90min; and (b) 80% solvent, 180°C and 150min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636mL/g and 17 °SR, respectively), and paper made from it the best breaking length (1709m), stretch (1.95%), burst index (0.98kN/g) and tear index (0.33mNm2/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose. [Copyright &y& Elsevier]

Abstract: The influence of temperature in the hydrothermal treatment of sunflower stalks on the composition of the liquid fraction obtained was examined. The remaining solid fraction was subjected to ethanol pulping in order to obtain pulp that was used to produce paper sheets. The pulp was characterized in terms of yield, kappa index, viscosity, and cellulose, hemicellulose and lignin contents; and the paper sheets in terms of breaking length, stretch, burst index and tear index. Hydrothermal treatment of the raw material at 190°C provided a liquid phase with maximal hemicellulose-derived oligomers and monosaccharide (glucose, xylose and arabinose) contents (26.9 and 4.2g/L, respectively). Pulping the solid fraction obtained by hydrothermal treatment at 180°C, with 70% ethanol at a liquid/solid ratio of 8:1 at 170°C for 120min provided pulp with properties on a par with those of soda pulp from the sunflower stalks, namely: 36.3% yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin and 551ml/g viscosity. Also, paper sheets obtained from the ethanol pulp were similar in breaking length (3.8km), stretch (1.23%), burst index (1.15kN/g) and tear index (2.04mNm2/g) to those provided by soda pulp. [Copyright &y& Elsevier]

Abstract: We characterized vine shoots, cotton stalks, Leucaena leucocephala and Chamaecytisus proliferus as pulping raw materials and found C. proliferus and cotton stalks to be the best for the intended purpose on the grounds of their increased contents in holocellulose (79.73% and 72.86%) and α-cellulose (45.37% and 58.48%), and their decreased contents in ethanol–benzene extractables (2.64% and 1.42%), hot water solubles (2.79% and 3.33%) and 1% soda solubles (16.67% and 20.34%). These properties resulted in increased pulp yields and hence in efficient use of these two types of raw material. The previous raw materials were pulped by using an ethyleneglycol concentration of 65% at 180°C for 75min, followed by beating at 1500 revolutions in a PFI refiner. The paper sheets obtained were characterized and those from C. proliferus found to be the best overall as they exhibited an increased breaking length (4644m), stretch (2.87%), burst index (2.46kN/g) tear index (0.33mNm2/g) and brightness (49.92% ISO); in addition C. proliferus pulp was obtained with a high-yield (62.88%). On the other hand, vine shoots provided the poorest results among the studied raw materials. [Copyright &y& Elsevier]

Abstract: To determine the overall efficiency of processes designed to convert lignocellulosic polysaccharides to ethanol, it is first necessary to determine the composition of the lignocellulosic substrates. Three standard methods routinely referenced in the literature for this purpose are monoethanolamine, trifluoroacetic acid and concentrated sulphuric acid-based methods. However, in the course of our studies, the suitability of these standard methods for analysis of wastepaper and wheat straw came into question. This paper details our investigations in this area, together with recommendations for appropriate modifications to one of the standard methods for reproducible and representative lignocellulosic compositional analysis of waste paper and cereal straw. [Copyright &y& Elsevier]

Abstract: The operating conditions for an organosolv (ethyleneglycol) and two alkaline (soda–anthraquinone and kraft) processes for obtaining cellulose pulp and paper from holm oak (Quercus ilex) wood trimmings were optimized. A range of variation for each process variable (viz. temperature, cooking time and soda or ethyleneglycol concentration) was established and a central composite experimental design involving three independent variables at three different variation levels was applied. The results obtained with the three cooking processes used were compared and those provided by the kraft process were found to be the best. Thus, the tensile index values it provided (5.9–16.3Nm/g) were 23.7% and 41.5% better than those obtained with the soda–AQ and ethyleneglycol processes, respectively. Also, the kraft process provided the best burst index, brightness and kappa number values. Based on the optimum working ranges, the temperature and cooking time were the variables resulting in the most and least marked changes, respectively, in pulp properties. [Copyright &y& Elsevier]

Abstract: This paper examines the influence of the degree of refining of different pulps, produced from olive trimmings and eucalyptus wood, on various physical properties. Corresponding pulps were obtained by means of different cooking processes. Pulp from olive trimmings was obtained by means of an organosolv process and pulp from eucalyptus was obtained by means of a kraft process. Pulp from olive trimmings exhibited a lower specific surface area, water retention volume, breaking length, stretch and burst index, but a higher porosity, than eucalyptus pulp. On the other hand, the same degree of refining was achieved with less energy for olive pulp than for eucalyptus pulp. Mixed pulp from olive trimmings and eucalyptus provided paper sheets with acceptable physical properties but with reduced refining energy costs relative to eucalyptus pulp alone. [Copyright &y& Elsevier]

Abstract: The influence of temperature (150–170°C), pulping time (15–45min) and soda concentration (5–10%) in the pulping of abaca on the yield, kappa, viscosity, breaking length, stretch and tear index of pulp and paper sheets, was studied. Using a factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the pulping process were derived that reproduced the former with errors lower than 25%. Using a high temperature, and a medium time and soda concentration, led to pulp that was difficult to bleach (kappa 28.34) but provided acceptable strength-related properties (breaking length 4728m; stretch 4.76%; tear index 18.25mNm2/g), with good yield (77.33%) and potential savings on capital equipment costs. Obtaining pulp amenable to bleaching would entail using more drastic conditions than those employed in this work. [Copyright &y& Elsevier]

The XOAZRP TCF sequence was applied to bleach wheat straw pulp. Following each bleaching stage, the properties of the pulp (viz. kappa number, standard viscosity, borohydride viscosity and brightness) and of the resulting effluents were determined. The performance of the reagents was analyzed through the studies of xylanase treatment and crystallinity and scanning electron microscopy of the pulps. Finally, the pulp was refined at 1000 revolutions in a PFI mill and the mechanical properties of the resulting paper were determined and compared with those of paper from a eucalyptus pulp. Despite its shortcomings, wheat straw pulp can be effectively bleached with the proposed TCF sequence. [Copyright &y& Elsevier]

The influence of the operating conditions used in the bleaching of olive wood trimmings pulp (viz. hydrogen peroxide concentration and time) on the yield, kappa index and viscosity of the resulting pulp and on strength-related properties of paper sheets was studied to determine the optimal bleaching conditions of this pulp. Hydrogen peroxide bleached pulps at different sequences (oxygen, ozone, chlorine dioxide and alkaline extractions) were compared. Hydrogen peroxide bleaching proved to be suitable for this pulp. Considerable improvements in viscosity were obtained with respect to other bleaching sequences such as oxygen, ozone and chlorine dioxide. Hydrogen peroxide bleaching decreased the kappa index 51.3% less than ozone bleaching, 25.0% less than chlorine dioxide (D) and 6.3% less combined chlorine dioxide-alkaline extraction (DE). To obtain kappa indices 50.9% and 37.9% lower than the index achieved by hydrogen peroxide, oxygen (LaOp) and ozone (LaO(LaZ)R) sequences respectively were needed. Lower-medium levels of hydrogen peroxide concentrations (1–3%) and high reaction times (210 min) proved to be suitable for bleaching of pulp olive trimming residues. This approach could be used on this residue to produce adequately bleached pulp. [Copyright &y& Elsevier]

The influence of independent variables in the pulping of wheat straw by use of an ethanol–acetone–water mixture [processing temperature and time, ethanol/(ethanol + acetone) value and (ethanol + acetone)/(ethanol + acetone + water) value] and of the number of PFI beating revolutions to which the pulp was subjected, on the properties of the resulting pulp (yield and Shopper–Riegler index) and of the paper sheets obtained from it (breaking length, stretch, burst index and tear index) was examined.By using a central composite factor design and the BMDP software suite, equations that relate each dependent variable to the different independent variables were obtained that reproduced the experimental results for the dependent variables with errors less than 30% at temperatures, times, ethanol/(ethanol + acetone) value, (ethanol + acetone)/(ethanol + acetone + water) value and numbers of PFI beating revolutions in the ranges 140–180 °C, 60–120 min, 25–75%, 35–75% and 0–1750, respectively.Using values of the independent variables over the variation ranges considered provided the following optimum values of the dependent variables: 78.17% (yield), 15.21 °SR (Shopper–Riegler index), 5265 m (breaking length), 1.94% (stretch), 2.53 kN/g (burst index) and 4.26 mN m2/g (tear index).Obtaining reasonably good paper sheets (with properties that differed by less than 15% from their optimum values except for the burst index, which was 28% lower) entailed using a temperature of 180 °C, an ethanol/(ethanol + acetone) value of 50%, an (ethanol + acetone)/(ethanol + acetone + water) value of 75%, a processing time of 60 min and a number of PFI beating revolutions of 1750. The yield was 32% lower under these conditions, however.A comparison of the results provided by ethanol, acetone and ethanol–acetone pulping revealed that the second and third process-which provided an increased yield were the best choices. On the other hand, if the pulp is to be refined, ethanol pulping is the process of choice. [Copyright &y& Elsevier]

• Overall, synergism was observed across all temperature ranges (25–52 °C). • PC can be used for VFA production at temperature of ≥42 °C. • Optimized temperature for PWC, FWC and OFMSW were 52, 37 and 42 °C respectively. • Mainly, acetic and butyric acids were produced from PC at 52 °C and FC at 37 °C. This study explores individual contributions and synergistic effects of food and paper, main components of organic fraction of municipal solid waste (OFMSW) towards volatile fatty acids (VFA) fermentation under different temperatures (25, 37, 42 and 52 °C). Thanks to the synergism of food and paper component (FC & PC), the results revealed that OFMSW is suitable for VFA production. Maximum VFA production was noticed to be 21.5 mg/L at 42 °C, ~2.1, and 1.42 times higher than fermentation of PC and FC. Enhanced hydrolysis of PC occurred at >37 °C, increasing alkalinity in leachate to 6.7 g/L at 42 °C, thus maintaining a stable pH (5.4–5.6) during acidogenic fermentation. Additionally, 74% of COD is hydrolyzed, of which 79% is converted to VFA based on biodegradable carbon at 42 °C. It is suggested that co-existence of FC and PC can enhance VFA production of OFMSW, and targeted VFA production can be maximized through process optimization. [ABSTRACT FROM AUTHOR]

• Hydrogen bonds formed in the LTTMs enabled the removal of lignin from EFB. • Clear separation of precipitated lignin was observed in EFB strands after washing. • EFB powder showed stronger molecular bonding of pulp than EFB strands. • Paper formed from cactus based LTTMs-delignified EFB had less void space and pores. The aim of this work was to recover the cellulose fibers from EFB using low-transition-temperature-mixtures (LTTMs) as a green delignification approach. The hydrogen bonding of LTTMs observed in 1H NMR tends to disrupt the three-dimensional structure of lignin and further remove the lignin from EFB. Delignification process of EFB strands and EFB powder were performed using standard l -malic acid and cactus malic acid-LTTMs. The recovered cactus malic acid-LTTMs showed higher glucose concentration of 8.07 mg/mL than the recovered l -malic acid LTTMs (4.15 mg/mL). This implies that cactus malic acid-LTTMs had higher delignification efficiency which led to higher amount of cellulose hydrolyzed into glucose. The cactus malic acid-LTTMs-delignified EFB was the most feasible fibers for making paper due to its lowest kappa number of 69.84. The LTTMs-delignified EFB has great potential to be used for making specialty papers in pulp and paper industry. [ABSTRACT FROM AUTHOR]