Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethano...Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethanol production.Cellulose and hemicellulose,when hydrolyzed into their component sugars,can be converted into ethanol through well established fermentation technologies.However,sugars necessary for fermentation are trapped inside the crosslinking structure of the lignocellulose.Hence,pretreatment of biomass is always necessary to remove and/or modify the surrounding matrix of lignin and hemicellulose prior to the enzymatic hydrolysis of the polysaccharides(cellulose and hemicellulose)in the biomass.Pretreatment refers to a process that converts lignocellulosic biomass from its native form,in which it is recalcitrant to cellulase enzyme systems,into a form for which cellulose hydrolysis is much more effective.In general,pretreatment methods can be classified into three categories,including physical,chemical,and biological pretreatment.The subject of this paper emphasizes the biomass pretreatment in preparation for enzymatic hydrolysis and microbial fermentation for cellulosic ethanol production.It primarily covers the impact of biomass structural and compositional features on the pretreatment,the characteristics of different pretreatment methods,the pretreatment study status,challenges,and future research targets.展开更多
Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the...Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.展开更多
Titanium dioxide nanoparticle was synthesized by the reduction of titanium tetrachloride using borohydride, water as solvent, and polyvinyl-pyrrolidone as stabilizer. The average size of nano-TiO2 is estimated to be 5...Titanium dioxide nanoparticle was synthesized by the reduction of titanium tetrachloride using borohydride, water as solvent, and polyvinyl-pyrrolidone as stabilizer. The average size of nano-TiO2 is estimated to be 5 - 10 nm using a transmission electron microscope (TEM);this was confirmed by X-ray diffraction and UV-Vis spectroscopy. Nano-TiO2 was impregnated into cotton fabric to impart multifunctional properties and this was confirmed by scanning electron microscope and scanning electron microscope coupled with high energy distribution X-Ray (SEM-EDX). The TiO2 nanoparticles loaded cotton fabrics showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) 96.6% and Klebsiella pneumonia (Gram negative) 95.2%. Also, TiO2 nanoparticles enhanced the self-cleaning and the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics. The TiO2 nanoparticles were durable in-situ cotton fabrics even after 20 laundering wash cycles.展开更多
Plant evolution, nutritional genomics, and mineral nutrition have been well documented but no studies have focused on the molecular adaptation of crop metabolism to wide variations of mineral ion composition and conce...Plant evolution, nutritional genomics, and mineral nutrition have been well documented but no studies have focused on the molecular adaptation of crop metabolism to wide variations of mineral ion composition and concentration. Diversification of peanut species from primary centers of domestication in South America depended on metabolic adaptation to the mineral ion conditions of the newer habitats. Understanding the diversification molecular biology of peanut metabolic pathways will permit the synthesis of the best mineral ion combinations for doubling CO2 assimilation. Valencia and Virginia cultivars belong to different subspecies of the tetraploid Arachis hypogaea. They were planted in the absence and presence of up to 99 mM (equivalent to 166 moles per hectare) of different mineral ions. Molecular properties of the primary metabolic pathways were studied by Northern analyses using Valencia GDH-synthesized RNAs as probes for Virginia mRNA and GDH-synthesized RNAs. Messenger RNAs are silenced by homologous RNAs synthesized by GDH. Peanut cellulose was analyzed by gravimetry;and fatty acids by HPLC. Complementary DNA probes made from Valencia GDH-synthesized RNAs hybridized perfectly to Virginia mRNAs and GDH-synthesized RNAs. Wide variations in mineral ion compositions and concentrations induced the GDHs of Valencia and Virginia to synthesize RNAs that differentially down-regulated the mRNAs encoding phosphate translocator, granule-bound starch synthase, phosphoglucomutase, glucosyltransferase, acetyl CoA carboxylase, nitrate reductase, and NADH-glutamate synthase so that the percent weights of oil (41.53 ± 8.75) and cellulose (30.29 ± 3.12) were similar in the control and mineral-treated peanuts. Therefore, RNA sequences that defined the molecular adaptation of mRNAs encoding the enzymes of primary metabolism were the same in the varietal types of A. hypogaea, in agreement with genetic data suggesting that tetraploid Arachis evolved relatively recently from the wild diploid ancestral species. Another molecula展开更多
The Far East population of Miscanthus sinensis (Andersson) was introduced into the West Siberia conditions. There was distinguished a form with a modified structure of the rootage which forms long shoots with leader b...The Far East population of Miscanthus sinensis (Andersson) was introduced into the West Siberia conditions. There was distinguished a form with a modified structure of the rootage which forms long shoots with leader buds and rapidly colonizes soil, thus forming a continuous and flat (without tussocks) plantation of miscanthus. It is shown that using usual agrotechnologies, it is possible to obtain 10-15 tons of dry biomass of high quality cellulose (about 40%) per ha/year.展开更多
Carboxyethylation pretreatment was used to prepare microfibrillated cellulose(MFC)in this study.In order to evaluate the adaptability of this pretreatment method,carboxyethylated MFC was prepared from six different ce...Carboxyethylation pretreatment was used to prepare microfibrillated cellulose(MFC)in this study.In order to evaluate the adaptability of this pretreatment method,carboxyethylated MFC was prepared from six different cellulosic materials.The carboxyl content,degree of polymerization,water retention value,charge density,chemical structure,size distribution,and micromorphology of the materials before and after pretreatment and grinding were studied and compared.The viscosity,ultraviolet(UV)transmittance,and thermal stability of the MFC samples at a certain concentration were determined.The results showed that the carboxyl content,water retention value,charge density,degree of polymerization,size distribution,and micromorphology of the pretreated and ground samples varied with those of the raw materials.The initial viscosity varied based on the type of raw material used.The MFC suspension prepared from cotton linter pulp had the highest UV transmittance,while the MFC prepared from bleached softwood kraft pulp had the highest viscosity at a low shear rate.After thermal degradation,the amount of residual char from the MFC prepared with the thermo-mechanical pulp was slightly higher than that of the other MFCs.This study demonstrates that carboxyethylation is an effective pretreatment method for different cellulosic materials.展开更多
In this paper, the rapid liquefaction of a corncob was achieved by plasma electrolysis, providing a new method for cellulosic biomass liquefaction. The liquefaction rate of the corncob was 95% after 5 min with polyeth...In this paper, the rapid liquefaction of a corncob was achieved by plasma electrolysis, providing a new method for cellulosic biomass liquefaction. The liquefaction rate of the corncob was 95% after 5 min with polyethylene glycol and glycerol as the liquefying agent. The experiments not only showed that H~+ ions catalyzed the liquefaction of the corncob, but also that using accelerated H~+ ions, which were accelerated by an electric field, could effectively improve the liquefaction efficiency. There was an obvious discharge phenomenon, in which the generated radicals efficiently heated the solution and liquefied the biomass, in the process of plasma electrolytic liquefaction. Finally, the optimum parameters of the corncob liquefaction were obtained by experimentation, and the liquefaction products were analyzed.展开更多
Instead of finishing the fabrics with inorganic particles by a binder, in this study the fine aluminium oxide powder were added during the polymerization system of a monomer with functional hydroxyl groups HPMA. The h...Instead of finishing the fabrics with inorganic particles by a binder, in this study the fine aluminium oxide powder were added during the polymerization system of a monomer with functional hydroxyl groups HPMA. The hot alkaline testing showed that the Al<sub>2</sub>O<sub>3</sub> particles had reacted with the polymer latex. The absorbability and wash durability of the fabric treated with such a latex with Al<sub>2</sub>O<sub>3</sub> were measured.展开更多
We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-g...We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-gel process at low temperature. The samples were characterized by means of several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogra- vimetric analysis. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under UV-Vis illumination. Moreover, flame-retardancy was tested by vertical flame spread test. The optimum add-on value for donating flame-retardancy onto cellulosic fabric was obtained to be in the range of 15.24 to 23.20 g of the ZnO per 100 g of fabric. Thermogravimetric analysis of pure and flame-retarded samples were accomplished and discussed. The results obtained are in agreement with Wall effect theory and Coating theory. The originality of this work on introducing photoactive flame-retarded fibers is highly valuable for industrial implementation.展开更多
Polyfunctional reactive dyes have been introduced by the renowned dye manufacturers in the recent years for better exhaustion and fixation performance. This paper deals with evaluation of the dyeing performance of thr...Polyfunctional reactive dyes have been introduced by the renowned dye manufacturers in the recent years for better exhaustion and fixation performance. This paper deals with evaluation of the dyeing performance of three cellulosic fibres namely cotton, modal and lyocell with polyfunctional (Avitera Cardinal SE) reactive dye in comparison a bifunctional-(Novacron Brilliant Red FN-3GL) reactive dye. The purpose of this study is to achieve a better understanding of exhaustion and fixation behaviour in dyeing of cotton, modal and lyocell fibres using these two types of reactive dyes. The dyeing was carried out at four different shade% (1%, 2%, 3%, and 4%). Besides studying exhaustion (%) and fixation (%) along with K/S values of dyed fabrics, several other quality parameters e.g. bursting strength, pilling resistance and colour fastness to wash were also examined. Finally, the optimum combination among the three types of cellulosic fabrics and two types of reactive dyes was observed. Lyocell fabric and polyfunctional reactive dyes have been found more sustainable.展开更多
Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. For...Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. Fortunately, the thermophilic nature of C. thermocellum can be exploited in sequential culture. Experiments were conducted to determine the effect of feedstock particle size on fermentation by sequential cultures and to demonstrate this effect could be shown by gas production. Dual-temperature sequential cultures were conducted by first culturing with C. thermocellum (63°C, 48 h) before culturing with C. beijerinckii (35°C, 24 h). Switchgrass (2, 5 or 15 mm particle size) was the feedstock in submerged substrate (10% w/v) fermentation. The extent of fermentation was evaluated by gas production and compared by analysis of variance with Tukey’s test post hoc. C. thermocellum alone produced 78 kPa cumulative pressure (approx. 680 mL gas) when the particle size was 2 or 5 mm. The C. thermocellum cultures with 15 mm feedstock particles had a mean cumulative pressure of 15 kPa after 48 h, which was less than the 2 and 5 mm treatments (P °C) and inoculated with C. beijerinckii, and the cumulative pressures were reset to ambient, cumulative pressure values as great as 70 kPa (equivalent to an additional 670 mL gas) were produced in 24 h. Again, the longer (15 mm) particle size produced less gas (P < 0.05). When the substrates were inoculated with C. beijerinckii without previous fermentation by C. thermocellum, the mean cumulative pressures were approximately 10 kPa. These results indicate that biological pretreatment with C. thermocellum increased the availability of switchgrass carbohydrates to C. beijerinckii, and that gas production is suitable method to show the effectiveness of a pretreatment.展开更多
Biorefineries are keen to design optimal biomass supply chains to minimize production, harvest, transport, and other costs. Such a design problem is challenging with the availability of multiple feedstocks (agricultur...Biorefineries are keen to design optimal biomass supply chains to minimize production, harvest, transport, and other costs. Such a design problem is challenging with the availability of multiple feedstocks (agricultural residues, perennials such as energy crops, short rotation woody crops), sourced from multiple harvest sheds, and transported across multiple modes (trucks, rails, and barges). This paper presents a multi-period optimization model to analyze the feasibility of collection from multiple harvest sheds. The results are demonstrated for a case study location in Alpena, MI served by truck and water transport. The model results suggest that: i) perennial biomass with higher yields would be preferred due to higher biomass production per unit area;ii) transport from farther locations are warranted only if the biomass production costs in the farther harvest sheds are cheaper by 20% - 30% compared to the adjacent harvest shed;and iii) the local situations of a biorefinery—characterized by the parametric inputs in the model—play a key role in determining the optimal feedstock composition across multiple harvest sheds. The results also support long term contracts associated with high yielding perennial feedstocks such as energy crops and short rotation woody crops.展开更多
The production of cellulosic bioethanol from non-edible plants is drawing increasing attention, as it potentially avoids food-fuel competition. Because growing such plants on farmland indirectly reduces food availabil...The production of cellulosic bioethanol from non-edible plants is drawing increasing attention, as it potentially avoids food-fuel competition. Because growing such plants on farmland indirectly reduces food availability, the plants should be grown on marginal, non-arable lands. In this study, we evaluated the growth of cellulosic energy crops at a former mining site in Indonesia. This mine was abandoned because it contained few mineral deposits, and exposed subsoils rather than toxic soils prevented revegetation. In the first trial, growths of two energy plant species Erianthus spp. and Napier grass (Pennisetum purpureum) were compared with that of maize (Zea mays) at the mine site and a nearby degraded farm. Erianthus and Napier grass produced 11.7 and 22.5 t·ha-1 of shoot dry matter at 8 months after planting (MAP) in the farm respectively while maize plants failed to establish, but none of the three species grew at the mine. In the second trial, two-week-old seedlings of Erianthus and Napier grass rather than stem cuttings as used in the first trial were planted at the mine site. Erianthus and Napier grass produced 16.3 and 24.0 t·ha-1 of shoot dry matter over the course of 18 months, respectively. Application of organic fertilizer significantly increased shoot dry matter to 18.9 and 39.6 t·ha-1 in Erianthus and Napier grass, respectively. During the 18-month growth period, both of the energy plants significantly increased soil carbon at the 0 - 0.3 m depth from 0.33% to 1.15% - 1.23% when chemical fertilizer was applied and to 0.67% - 0.69% when both chemical and organic fertilizers were applied. From 0 - 5 MAP, soil surface level dropped by 28.0 - 34.7 mm in plots without plants due to soil erosion. In contrast, both of the energy plants significantly reduced the drop of soil surface level to 16.0 - 19.3 mm in plots with chemical fertilizer alone and to 18.0 - 20.7 mm in plots with chemical and organic fertilizers. Proportions of small soil particles, that would be easily detached and transported by wate展开更多
Cationic modifying agent ( PECH- amine) with lower molecular weight and containing less nitrogen was prepared and characterized. The water-soluble cationic modification agent has high reactivity for cotton. Cotton mod...Cationic modifying agent ( PECH- amine) with lower molecular weight and containing less nitrogen was prepared and characterized. The water-soluble cationic modification agent has high reactivity for cotton. Cotton modified by this agent can be dyed under salt-free and neutral conditions with direct and reactive dyes. Dyes in the dyebath could be completely exhausted and a dyeing effluent without residual dyes and salt could be expected.展开更多
文摘Bioconversion of lignocellulosic biomass to ethanol is significantly hindered by the structural and chemical complexity of biomass,which makes these materials a challenge to be used as feedstocks for cellulosic ethanol production.Cellulose and hemicellulose,when hydrolyzed into their component sugars,can be converted into ethanol through well established fermentation technologies.However,sugars necessary for fermentation are trapped inside the crosslinking structure of the lignocellulose.Hence,pretreatment of biomass is always necessary to remove and/or modify the surrounding matrix of lignin and hemicellulose prior to the enzymatic hydrolysis of the polysaccharides(cellulose and hemicellulose)in the biomass.Pretreatment refers to a process that converts lignocellulosic biomass from its native form,in which it is recalcitrant to cellulase enzyme systems,into a form for which cellulose hydrolysis is much more effective.In general,pretreatment methods can be classified into three categories,including physical,chemical,and biological pretreatment.The subject of this paper emphasizes the biomass pretreatment in preparation for enzymatic hydrolysis and microbial fermentation for cellulosic ethanol production.It primarily covers the impact of biomass structural and compositional features on the pretreatment,the characteristics of different pretreatment methods,the pretreatment study status,challenges,and future research targets.
基金This work was financially supported by Innovation Capability Support Program of Shaanxi(2020KJXX082)the Foundation(202005)of Tianjin Key Laboratory of Pulp&Paper(Tianjin University of Science&Technology).
文摘Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.
文摘Titanium dioxide nanoparticle was synthesized by the reduction of titanium tetrachloride using borohydride, water as solvent, and polyvinyl-pyrrolidone as stabilizer. The average size of nano-TiO2 is estimated to be 5 - 10 nm using a transmission electron microscope (TEM);this was confirmed by X-ray diffraction and UV-Vis spectroscopy. Nano-TiO2 was impregnated into cotton fabric to impart multifunctional properties and this was confirmed by scanning electron microscope and scanning electron microscope coupled with high energy distribution X-Ray (SEM-EDX). The TiO2 nanoparticles loaded cotton fabrics showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) 96.6% and Klebsiella pneumonia (Gram negative) 95.2%. Also, TiO2 nanoparticles enhanced the self-cleaning and the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics. The TiO2 nanoparticles were durable in-situ cotton fabrics even after 20 laundering wash cycles.
文摘Plant evolution, nutritional genomics, and mineral nutrition have been well documented but no studies have focused on the molecular adaptation of crop metabolism to wide variations of mineral ion composition and concentration. Diversification of peanut species from primary centers of domestication in South America depended on metabolic adaptation to the mineral ion conditions of the newer habitats. Understanding the diversification molecular biology of peanut metabolic pathways will permit the synthesis of the best mineral ion combinations for doubling CO2 assimilation. Valencia and Virginia cultivars belong to different subspecies of the tetraploid Arachis hypogaea. They were planted in the absence and presence of up to 99 mM (equivalent to 166 moles per hectare) of different mineral ions. Molecular properties of the primary metabolic pathways were studied by Northern analyses using Valencia GDH-synthesized RNAs as probes for Virginia mRNA and GDH-synthesized RNAs. Messenger RNAs are silenced by homologous RNAs synthesized by GDH. Peanut cellulose was analyzed by gravimetry;and fatty acids by HPLC. Complementary DNA probes made from Valencia GDH-synthesized RNAs hybridized perfectly to Virginia mRNAs and GDH-synthesized RNAs. Wide variations in mineral ion compositions and concentrations induced the GDHs of Valencia and Virginia to synthesize RNAs that differentially down-regulated the mRNAs encoding phosphate translocator, granule-bound starch synthase, phosphoglucomutase, glucosyltransferase, acetyl CoA carboxylase, nitrate reductase, and NADH-glutamate synthase so that the percent weights of oil (41.53 ± 8.75) and cellulose (30.29 ± 3.12) were similar in the control and mineral-treated peanuts. Therefore, RNA sequences that defined the molecular adaptation of mRNAs encoding the enzymes of primary metabolism were the same in the varietal types of A. hypogaea, in agreement with genetic data suggesting that tetraploid Arachis evolved relatively recently from the wild diploid ancestral species. Another molecula
文摘The Far East population of Miscanthus sinensis (Andersson) was introduced into the West Siberia conditions. There was distinguished a form with a modified structure of the rootage which forms long shoots with leader buds and rapidly colonizes soil, thus forming a continuous and flat (without tussocks) plantation of miscanthus. It is shown that using usual agrotechnologies, it is possible to obtain 10-15 tons of dry biomass of high quality cellulose (about 40%) per ha/year.
基金the financial support from the National Key Research and Development Program of China(2017YFB0307901,2017YFE0102500).
文摘Carboxyethylation pretreatment was used to prepare microfibrillated cellulose(MFC)in this study.In order to evaluate the adaptability of this pretreatment method,carboxyethylated MFC was prepared from six different cellulosic materials.The carboxyl content,degree of polymerization,water retention value,charge density,chemical structure,size distribution,and micromorphology of the materials before and after pretreatment and grinding were studied and compared.The viscosity,ultraviolet(UV)transmittance,and thermal stability of the MFC samples at a certain concentration were determined.The results showed that the carboxyl content,water retention value,charge density,degree of polymerization,size distribution,and micromorphology of the pretreated and ground samples varied with those of the raw materials.The initial viscosity varied based on the type of raw material used.The MFC suspension prepared from cotton linter pulp had the highest UV transmittance,while the MFC prepared from bleached softwood kraft pulp had the highest viscosity at a low shear rate.After thermal degradation,the amount of residual char from the MFC prepared with the thermo-mechanical pulp was slightly higher than that of the other MFCs.This study demonstrates that carboxyethylation is an effective pretreatment method for different cellulosic materials.
基金supported by the Natural Science Foundation of Guangdong Province, China (Grant No. 2015A030313005)the opening foundation (Grant No. 2016002) of Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang SciTech University)+2 种基金Fundamental Research Funds for the Central Universities, China (Grant No. 20720150022)Ministry of Educationthe Fund from the Fujian Provincial Key Laboratory for Plasma and Magnetic Resonance, China
文摘In this paper, the rapid liquefaction of a corncob was achieved by plasma electrolysis, providing a new method for cellulosic biomass liquefaction. The liquefaction rate of the corncob was 95% after 5 min with polyethylene glycol and glycerol as the liquefying agent. The experiments not only showed that H~+ ions catalyzed the liquefaction of the corncob, but also that using accelerated H~+ ions, which were accelerated by an electric field, could effectively improve the liquefaction efficiency. There was an obvious discharge phenomenon, in which the generated radicals efficiently heated the solution and liquefied the biomass, in the process of plasma electrolytic liquefaction. Finally, the optimum parameters of the corncob liquefaction were obtained by experimentation, and the liquefaction products were analyzed.
文摘Instead of finishing the fabrics with inorganic particles by a binder, in this study the fine aluminium oxide powder were added during the polymerization system of a monomer with functional hydroxyl groups HPMA. The hot alkaline testing showed that the Al<sub>2</sub>O<sub>3</sub> particles had reacted with the polymer latex. The absorbability and wash durability of the fabric treated with such a latex with Al<sub>2</sub>O<sub>3</sub> were measured.
文摘We have investigated the effect of zinc oxide as a photocatalyst and durable flame-retardant on cellulosic fibers. Zinc oxide nanocrystals were successfully synthesized and deposited onto cellulosic fibers using sol-gel process at low temperature. The samples were characterized by means of several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogra- vimetric analysis. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under UV-Vis illumination. Moreover, flame-retardancy was tested by vertical flame spread test. The optimum add-on value for donating flame-retardancy onto cellulosic fabric was obtained to be in the range of 15.24 to 23.20 g of the ZnO per 100 g of fabric. Thermogravimetric analysis of pure and flame-retarded samples were accomplished and discussed. The results obtained are in agreement with Wall effect theory and Coating theory. The originality of this work on introducing photoactive flame-retarded fibers is highly valuable for industrial implementation.
文摘Polyfunctional reactive dyes have been introduced by the renowned dye manufacturers in the recent years for better exhaustion and fixation performance. This paper deals with evaluation of the dyeing performance of three cellulosic fibres namely cotton, modal and lyocell with polyfunctional (Avitera Cardinal SE) reactive dye in comparison a bifunctional-(Novacron Brilliant Red FN-3GL) reactive dye. The purpose of this study is to achieve a better understanding of exhaustion and fixation behaviour in dyeing of cotton, modal and lyocell fibres using these two types of reactive dyes. The dyeing was carried out at four different shade% (1%, 2%, 3%, and 4%). Besides studying exhaustion (%) and fixation (%) along with K/S values of dyed fabrics, several other quality parameters e.g. bursting strength, pilling resistance and colour fastness to wash were also examined. Finally, the optimum combination among the three types of cellulosic fabrics and two types of reactive dyes was observed. Lyocell fabric and polyfunctional reactive dyes have been found more sustainable.
文摘Fermentation of cellulosic biomass can be done in a single step with cellulolytic, solventogenic bacteria, such as Clostridium thermocellum. However, the suite of products is limited in consolidated bioprocessing. Fortunately, the thermophilic nature of C. thermocellum can be exploited in sequential culture. Experiments were conducted to determine the effect of feedstock particle size on fermentation by sequential cultures and to demonstrate this effect could be shown by gas production. Dual-temperature sequential cultures were conducted by first culturing with C. thermocellum (63°C, 48 h) before culturing with C. beijerinckii (35°C, 24 h). Switchgrass (2, 5 or 15 mm particle size) was the feedstock in submerged substrate (10% w/v) fermentation. The extent of fermentation was evaluated by gas production and compared by analysis of variance with Tukey’s test post hoc. C. thermocellum alone produced 78 kPa cumulative pressure (approx. 680 mL gas) when the particle size was 2 or 5 mm. The C. thermocellum cultures with 15 mm feedstock particles had a mean cumulative pressure of 15 kPa after 48 h, which was less than the 2 and 5 mm treatments (P °C) and inoculated with C. beijerinckii, and the cumulative pressures were reset to ambient, cumulative pressure values as great as 70 kPa (equivalent to an additional 670 mL gas) were produced in 24 h. Again, the longer (15 mm) particle size produced less gas (P < 0.05). When the substrates were inoculated with C. beijerinckii without previous fermentation by C. thermocellum, the mean cumulative pressures were approximately 10 kPa. These results indicate that biological pretreatment with C. thermocellum increased the availability of switchgrass carbohydrates to C. beijerinckii, and that gas production is suitable method to show the effectiveness of a pretreatment.
文摘Biorefineries are keen to design optimal biomass supply chains to minimize production, harvest, transport, and other costs. Such a design problem is challenging with the availability of multiple feedstocks (agricultural residues, perennials such as energy crops, short rotation woody crops), sourced from multiple harvest sheds, and transported across multiple modes (trucks, rails, and barges). This paper presents a multi-period optimization model to analyze the feasibility of collection from multiple harvest sheds. The results are demonstrated for a case study location in Alpena, MI served by truck and water transport. The model results suggest that: i) perennial biomass with higher yields would be preferred due to higher biomass production per unit area;ii) transport from farther locations are warranted only if the biomass production costs in the farther harvest sheds are cheaper by 20% - 30% compared to the adjacent harvest shed;and iii) the local situations of a biorefinery—characterized by the parametric inputs in the model—play a key role in determining the optimal feedstock composition across multiple harvest sheds. The results also support long term contracts associated with high yielding perennial feedstocks such as energy crops and short rotation woody crops.
文摘The production of cellulosic bioethanol from non-edible plants is drawing increasing attention, as it potentially avoids food-fuel competition. Because growing such plants on farmland indirectly reduces food availability, the plants should be grown on marginal, non-arable lands. In this study, we evaluated the growth of cellulosic energy crops at a former mining site in Indonesia. This mine was abandoned because it contained few mineral deposits, and exposed subsoils rather than toxic soils prevented revegetation. In the first trial, growths of two energy plant species Erianthus spp. and Napier grass (Pennisetum purpureum) were compared with that of maize (Zea mays) at the mine site and a nearby degraded farm. Erianthus and Napier grass produced 11.7 and 22.5 t·ha-1 of shoot dry matter at 8 months after planting (MAP) in the farm respectively while maize plants failed to establish, but none of the three species grew at the mine. In the second trial, two-week-old seedlings of Erianthus and Napier grass rather than stem cuttings as used in the first trial were planted at the mine site. Erianthus and Napier grass produced 16.3 and 24.0 t·ha-1 of shoot dry matter over the course of 18 months, respectively. Application of organic fertilizer significantly increased shoot dry matter to 18.9 and 39.6 t·ha-1 in Erianthus and Napier grass, respectively. During the 18-month growth period, both of the energy plants significantly increased soil carbon at the 0 - 0.3 m depth from 0.33% to 1.15% - 1.23% when chemical fertilizer was applied and to 0.67% - 0.69% when both chemical and organic fertilizers were applied. From 0 - 5 MAP, soil surface level dropped by 28.0 - 34.7 mm in plots without plants due to soil erosion. In contrast, both of the energy plants significantly reduced the drop of soil surface level to 16.0 - 19.3 mm in plots with chemical fertilizer alone and to 18.0 - 20.7 mm in plots with chemical and organic fertilizers. Proportions of small soil particles, that would be easily detached and transported by wate
文摘Cationic modifying agent ( PECH- amine) with lower molecular weight and containing less nitrogen was prepared and characterized. The water-soluble cationic modification agent has high reactivity for cotton. Cotton modified by this agent can be dyed under salt-free and neutral conditions with direct and reactive dyes. Dyes in the dyebath could be completely exhausted and a dyeing effluent without residual dyes and salt could be expected.
