Sawdust xanthate modified with ethanediamine was used for the removal of Cu（Ⅱ） and Ni（Ⅱ） from aqueous solution. The influence of various operating parameters such temperature and adsorbent dosage on the adsorpti...Sawdust xanthate modified with ethanediamine was used for the removal of Cu（Ⅱ） and Ni（Ⅱ） from aqueous solution. The influence of various operating parameters such temperature and adsorbent dosage on the adsorption isotherms of modified sawdust was investigated. Thermodynamic parameters, namely Gibbs free energy （△GΘ）, enthalpy （△HΘ） and entropy （△SΘ） of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were calculated, showing that the adsorption is a spontaneous and exothermic process. The modified extended Langmuir equation approaches provide excellent prediction of the binary adsorption. In single and binary systems, the overall adsorption data were best described by the pseudo-second order kinetic model, then the calculated values of activation energy of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were 59.12 and 55.92 kJ/mol respectively. The results show that the affinity of each metal ion onto the modified sawdust surface is influenced by the presence of the other one.展开更多
The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied...The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied. The equilibrium time was found to be of the order of 60 min. Kinetics fit pseudo first-order, second-order and intraparticle diffusion models, hence adsorption rate constants were calculated. The adsorption data of metal ions at temperatures of 25, 45 and 60~C have been described by the Freundlich and Langmuir isotherm models. The thermodynamic parameters such as energy, entropy and enthalpy changes for the adsorption of heavy metal ions have also been computed and discussed. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the walnut sawdust. The selectivity order of the adsorbent is Pb（I1）~Cd（II）〉Ni（I1）. From these results, it can be concluded that the sawdust of walnut could be a good adsorbent for the metal ions from aqueous solutions.展开更多
The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fu...The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465 ℃, 61% at 490℃ and 60% at 475℃ respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.展开更多
The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,con...The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.展开更多
The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carded out in a self-manufactured vacuum pyrolysis reactor. The effects...The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carded out in a self-manufactured vacuum pyrolysis reactor. The effects of the system pressure and the activation condition （nitrogen or vacuum） on pore development were investigated. The results show that both high quality activated carbon and high added-value bio-oil can be obtained simultaneously via vacuum chemical activation. The characteristics of the activated carbons produced under vacuum conditions are better than those prepared under nitrogen atmosphere. The performance parameters of the activated carbon obtained under vacuum conditions are as follows： the pore size distribution is mainly microporous, the Brunauer-Emmett-Teller （BET） surface area is 1 070.59 m^2/g, the microporous volume is 0.502 4 cm^3/g, the average pore size is 2.085 nm, and the iodine adsorption value and the methylene blue adsorption value are 1 142.92 and 131.34 mg/g, respectively. The activated carbon from vacuum chemical activation has developed micropores, and the N2 adsorption equilibrium constant of the corresponding activated carbon gradually increases with the decrease of reaction system pressure.展开更多
Manganese （Mn） leaching and recovery from low-grade pyrolusite ore were studied using sulfiaric acid （H2SO4） as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pr...Manganese （Mn） leaching and recovery from low-grade pyrolusite ore were studied using sulfiaric acid （H2SO4） as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were inves- tigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H2SO4 using a liq- uid/solid ratio of 6.0 mL/g for 90min at 90℃. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.展开更多
In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fun...In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fungi with sufficient cellulose, hemicellulose and lignin and a small amount of nitrogen, phosphorus, potassium, calcium, magnesium, other mineral salts, and some vitamins for the growth of edible fungi. However, the Pinus massoniana wood contained a significant amount of terpenoids, which are detrimental to the growth of edible fungus and mycelial. The major and current detoxification methods for Pinus massoniana sawdust were analyzed, such as steaming method, distillation method, lime water immersion method, outdoor piling fermentation method, and chemical method. Their advantages and disadvantages were discussed and reviewed. Finally, the major issues in the application of Pinus massoniana sawdust as the cultivation substrate of edible fungi were analyzed, and the application prospect of Pinus massoniana sawdust as the substrate for the cultivation of edible fungi was also reviewed.展开更多
This study investigated the effects of sawdust as a soil amendment on certain growth parameters of Solanum esculentum Linn. grown in soil polluted with various concentrations of waste engine oil, and changes in the ph...This study investigated the effects of sawdust as a soil amendment on certain growth parameters of Solanum esculentum Linn. grown in soil polluted with various concentrations of waste engine oil, and changes in the physicochemical proper- ties of the soil. The purpose was to assess the soil remediation potentials of sawdust in waste engine oil-polluted soil. The experiment was divided into three regimes： control （air-dried soil without waste engine oil and with clean sawdust）, pol- luted （waste engine oil-contaminated soil）, and amended （oil-polluted soil amended with sawdust）. Enough 3-kg soil samples were sieved and air-dried to prepare five treatment levels of waste engine oil-contaminated soil （30 mL, 1%; 60 mL, 2%; 90 mL, 3%; 120 mL, 4%; and 150 mL, 5%）, as well as five additional treatment levels （the same amounts ofoil contamination） in soil amended with sawdust. The treatment levels were replicated five times in a completely randomized design. A nursery bed was planted with a hybrid tomato variety （Roma V F） obtained from National Horticultural Research Institute （NIHORT） in Ibadan, Nigeria. During the maturation period, the growth parameters such as plant height, number of leaves, and number of branches per plant were determined and then the harvested plants were oven dried at 70 ℃for 48 hours to determine their dry weights. The effects of the sawdust amendment on the soil were assessed by determining the soil pH （glass electrode pH meter）, total nitrogen （Kjeldahl method）, total phosphorus （Bray-1 solution）, and potassium （on the leacheate by a flame photometer）. Chromium, lead, and cadmium contents were determined using an atomic absorption spectrophotometer. Analysis of variance and a Duncan multiple-range test were employed to test significant differences in the soil properties of the three regimes. The growth performance ofSolanum esculentum Linn. in the amended regime （soil with sawdust） at the 150-mL waste engine oil-contamination level was significantly higher than in the polluted regime （soil without sawdust）. After plant harvest, the pH of the soil was shown to be clearly affected by the addition of waste engine oil. The control soil （air-dried only, no sawdust, no oil） had the highest pH value, 6.60, which was significantly different from the pH values at other levels of waste engine oil contamination. However, when amended with sawdust, the control soil had a significantly lower pH value than the unamended control soil. This study further demonstrates that sawdust has the potential of amending waste engine oil-contaminated soil for increasing tomato growth performance because it is capable of increasing the soil nutrient content and reducing the soil total hydrocarbon content.展开更多
Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catal...Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.展开更多
This work studied the effects of firing temperatures on the refractory properties of insulating firebricks produced from a blend of hydrometallurgically purified clay, high alumina cement and sawdust. Twenty grams out...This work studied the effects of firing temperatures on the refractory properties of insulating firebricks produced from a blend of hydrometallurgically purified clay, high alumina cement and sawdust. Twenty grams out of a bulk (1000 Kg) of clay obtained from Ipetumodu in Nigeria was analyzed for size range, consequent upon which the remaining bulk was sieved to 100 μm, being the average size. The bulk was there after leached under a predetermined condition (1.6 mol/dm3 of oxalic acid at 70oC for 150 min and 200 rev/min agitation speed) and cylindrical samples (5 cm diameter by 5 cm high) containing different quantities of high alumina cement (5% - 20%) and sawdust (1% - 5%) were prepared, dried at 110oC and subsequently fired at 900oC, 1100oC, 1300oC and 1500oC, at the rate of 4oC/min and soaked for 2 hrs. These samples were subjected to different refractory tests (permanent linear change, modulus of rupture, bulk density, cold crushing strength and apparent porosity). Even though samples containing more than 20% alumina crumbled at elevated temperatures, it was still observed that the bricks performed to expectations at lower alumina contents, even at 1500oC. The sample containing 3% sawdust and 10% alumina cement however, gave the desired requirement for preparing good insulating firebricks with reliable phase integrity, as revealed by scanning electron microscopy (SEM).展开更多
This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium ...This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium and high density timber species. Particle sizes of maize cobs and sawdust used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (Sawdust:maize cobs). Briquettes were produced at room temperature (28°C) using compacting pressures 20, 30, 40 and 50 MPa. The results suggested that combining maize cob particles with sawdust of low, medium and high density wood species could significantly enhance the relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from agricultural biomass residue like maize cobs. The results further indicated that the physical and mechanical characteristics of briquettes produced from combinations of sawdust of low density species and maize cobs were exceptionally higher than that produced from combinations of maize cob particles, and medium density and high density timber species. The R2 values for the regression model between the independent variables (mixing percentage and compacting pressure) and relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from combinations of maize cob particles and sawdust of low density species (Ceiba pentandra) were 0.966, 0.932 and 0.710 respectively. This study provides a hope for briquetting maize cobs at room temperature using a low compacting pressure.展开更多
The effects of sulfuric acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust were investigated in this study.Sulfuric acid could act as an acidic catalyst to depolymerize holocellulose th...The effects of sulfuric acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust were investigated in this study.Sulfuric acid could act as an acidic catalyst to depolymerize holocellulose through cleavage of the glycosidic bonds,the dissociation energies of which were supplied by the impact of a ball on pine sawdust,during milling.The destruction of glycosidic and hydrogen bonds in pine sawdust resulted in a decrease of crystallinity and an increase of water solubility.The sulfuric acid could promote the hydrolysis of holocellulose and its hydrolysis products.It also destroyed the chemical linkages between holocellulose and lignin during ball milling.The cleavage of chemical linkages with holocellulose made lignin more difficult to hydrolyze in subcritical water,and higher activation energy was needed to hydrolyze pretreated pine sawdust at higher reaction temperatures.It also led to the formation of glucose char and aromatic-linked polymer char from the hydrolysis products of holocellulose.展开更多
In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll ...In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.展开更多
Many timber producing countries generate more than 2 million m3 of sawdust annually. In developing countries, sawdust is often disposed of by open dumping, open burning, or dumping in landfills. This poses huge enviro...Many timber producing countries generate more than 2 million m3 of sawdust annually. In developing countries, sawdust is often disposed of by open dumping, open burning, or dumping in landfills. This poses huge environmental challenges related to air pollution, greenhouse gas emissions, and destruction of plant and aquatic life. Findings from this review article reveal that sawdust can be used to make sawdust construction composites with good modulus of elasticity, water absorption and strength characteristics that satisfy international specifications. These composites include particleboards, sawdust concrete blocks or bricks and sawdust concrete. The article concludes that partially replacing 5% to 17% of sand with sawdust, or replacing cement with sawdust ash in proportions of 5% to 15% in concrete mixes can produce structural concrete with compressive strengths greater than 20 MPa. Partially replacing 10% to 30% of sand used in the manufacture blocks and bricks with sawdust can also produce sawdust bricks and blocks with compressive strengths greater than 3 MPa. Sawdust composites are also attractive for their low thermal conductivity, high sound absorption and good sound insulation characteristics. These findings indicate that increased utilisation of sawdust composites in construction will mitigate against potential sawdust environmental pollution, conserve energy and reduce disposal costs.展开更多
The thermodynamics and sorption efficiencies for the remediation of Cr, Ni and Cd from their aqueous solutions using Maize Cob (MC) and Sawdust (SD) in a batch system are reported. Efficiencies were judged based on pa...The thermodynamics and sorption efficiencies for the remediation of Cr, Ni and Cd from their aqueous solutions using Maize Cob (MC) and Sawdust (SD) in a batch system are reported. Efficiencies were judged based on parameters such as sorbent weight, initial adsorbate loading concentration, pH and surface area. Shimadzu AA650 Double Beam Atomic Absorption/Flame spectrophotometer was employed to study concentration differences before and after the adsorption process. Parameters such as ΔH, ΔS and ΔG were determined. On MC, ΔH varied as 1466.59, 1271.21 and 1347.70kJmol-1 for Cr, Ni and Cd respectively. While on SD it varied as -566.85, 256.32 and 888.77kJmol-1respectively for the same order of metal ions. The three ions were found to be chemisorbed onto MC, while on SD Cr and Ni were physisorbed and Cd remains chemisorbed as suggested by Freundlich isotherm.展开更多
Sawdust which is basically considered as?a timber-industrial waste?that pollutes the environment can become a valuable commodity which is considered in three ways: Manufacturing, Energy and Agricultural utilization. T...Sawdust which is basically considered as?a timber-industrial waste?that pollutes the environment can become a valuable commodity which is considered in three ways: Manufacturing, Energy and Agricultural utilization. The sawdust is burnt in an updraft gasifier under a limited supply of air to obtain?producer gas which is carbon II oxide and hydrogen as main components. The sawdust and other biomass materials are mixed in certain proportions, then bound together and palletized to a small blocks called briquettes. The material?was also considered to be composted by mixing it with animal digestion or?wood ashes and calcium carbonate to form fertilizers. The sawdust and wood shavings can be used for particle board as well as oil production.展开更多
Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other woo...Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other wood-based industries (e.g. furniture, floor production), which do not use water for manufacturing processes, generate different wastewater streams after: 1) cleaning/washing of machinery that applies adhesives and coatings onto wood surfaces;2) cleaning/washing of machinery that applies specific products for the curing phase of adhesives;3) cleaning/washing of sharp planar blades used for the sawn process and to prepare wood surfaces for the adhesive application;4) cleaning/washing of the floor;5) cleaning/washing of trucks and vehicles. The dilution of low-volumes of highly polluted wastewater is not acceptable any longer since conventional treatment plants are not designed for these types of industrial wastewater. There is a need for proper characterization, treatability studies, designing and testing alternative small size and cost-effective treatment systems for on-site implementation. Treatment systems based on sorption mechanisms are flexible, easy to operate and generate less sludge and several low-cost sorbents generated by forestry activities have advantageous physico-chemical characteristics. The current paper presents the preliminary results from a pilot treatment system consisting of an equalization tank, settling/sedimentation and two sorption reactors in parallel using Pinus sylvestris sawdust as sorbent implemented as part of an integrated water management plan in a wood-floor industry. The simple to operate and cost-effective pilot treatment system performs satisfactorily during an initial period of operation. The study shows an average 39% - 54% reduction of TPH;17% - 38% reduction of oil;2% - 15% of reduction of COD and;11% - 74% reduction of most toxic metals but for Co, Ni and Zn in the system B. Based on these results, Pinus sylvestris sawdust is a potential low-cost and abundant material to be considered for industrial wastewater treatment plants.展开更多
In this research, composites based on treated tropical sawdust and polypropylene (PP) were prepared using hot press molding machine. Raw sawdust was chemically treated with monomer, 2 - ethylhexyl methacrylate in orde...In this research, composites based on treated tropical sawdust and polypropylene (PP) were prepared using hot press molding machine. Raw sawdust was chemically treated with monomer, 2 - ethylhexyl methacrylate in order to improve the mechanical properties of the composites. The influence of the chemically treated sawdust on the physical and mechanical properties of sawdust-PP composites were investigated at various loading level from 10 wt.% up to 30 wt.%. Results indicate that the mechanical properties of the chemically treated sawdust–PP composites were found to be higher than those of the raw ones respectively. The surface morphology obtained from scanning electron microscopy (SEM) showed that raw sawdust–PP composites possess surface roughness and weak interfacial adhesion between the matrix and the filler while the chemically treated one showed improved filler–matrix interaction. This indicates that better dispersion of the filler with the PP matrix has occurred upon chemical treatment of the filler. Water absorption tests showed that composites prepared from the chemically treated sawdust absorb lower amount of water compared to the ones prepared from raw sawdust, suggesting that hydrophilic nature of the cellulose in the sawdust has significantly decreased upon chemical treatment.展开更多
基金Project(41061044)supported by the National Natural Science Foundation of ChinaProjects(2010GXNSFD013016,2012GXNSFAA053017)supported by the Natural Science Foundation of Guangxi,China
文摘Sawdust xanthate modified with ethanediamine was used for the removal of Cu（Ⅱ） and Ni（Ⅱ） from aqueous solution. The influence of various operating parameters such temperature and adsorbent dosage on the adsorption isotherms of modified sawdust was investigated. Thermodynamic parameters, namely Gibbs free energy （△GΘ）, enthalpy （△HΘ） and entropy （△SΘ） of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were calculated, showing that the adsorption is a spontaneous and exothermic process. The modified extended Langmuir equation approaches provide excellent prediction of the binary adsorption. In single and binary systems, the overall adsorption data were best described by the pseudo-second order kinetic model, then the calculated values of activation energy of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were 59.12 and 55.92 kJ/mol respectively. The results show that the affinity of each metal ion onto the modified sawdust surface is influenced by the presence of the other one.
文摘The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied. The equilibrium time was found to be of the order of 60 min. Kinetics fit pseudo first-order, second-order and intraparticle diffusion models, hence adsorption rate constants were calculated. The adsorption data of metal ions at temperatures of 25, 45 and 60~C have been described by the Freundlich and Langmuir isotherm models. The thermodynamic parameters such as energy, entropy and enthalpy changes for the adsorption of heavy metal ions have also been computed and discussed. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the walnut sawdust. The selectivity order of the adsorbent is Pb（I1）~Cd（II）〉Ni（I1）. From these results, it can be concluded that the sawdust of walnut could be a good adsorbent for the metal ions from aqueous solutions.
文摘The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465 ℃, 61% at 490℃ and 60% at 475℃ respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.
基金the Universiti Sains Malaysia for the financial support (No. 304/PKIMIA/638056)
文摘The potential of base treated Shorea dasyphylla（BTSD） sawdust for Acid Blue 25（AB 25） adsorption was investigated in a batch adsorption process.Various physiochemical parameters such as pH,stirring rate,dosage,concentration,contact time and temperature were studied.The adsorbent was characterized with Fourier transform infrared spectrophotometer,scanning electron microscope and Brunauer,Emmett and Teller analysis.The optimum conditions for AB 25 adsorption were pH 2,stirring rate 500 r/min,adsorbent dosage 0.10 g and contact time 60 min.The pseudo second-order model showed the best conformity to the kinetic data.The equilibrium adsorption of AB 25 was described by Freundlich and Langmuir,with the latter found to agree well with the isotherm model.The maximum monolayer adsorption capacity of BTSD was 24.39 mg/g at 300 K,estimated from the Langmuir model.Thermodynamic parameters such as Gibbs free energy,enthalpy and entropy were determined.It was found that AB 25 adsorption was spontaneous and exothermic.
文摘The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carded out in a self-manufactured vacuum pyrolysis reactor. The effects of the system pressure and the activation condition （nitrogen or vacuum） on pore development were investigated. The results show that both high quality activated carbon and high added-value bio-oil can be obtained simultaneously via vacuum chemical activation. The characteristics of the activated carbons produced under vacuum conditions are better than those prepared under nitrogen atmosphere. The performance parameters of the activated carbon obtained under vacuum conditions are as follows： the pore size distribution is mainly microporous, the Brunauer-Emmett-Teller （BET） surface area is 1 070.59 m^2/g, the microporous volume is 0.502 4 cm^3/g, the average pore size is 2.085 nm, and the iodine adsorption value and the methylene blue adsorption value are 1 142.92 and 131.34 mg/g, respectively. The activated carbon from vacuum chemical activation has developed micropores, and the N2 adsorption equilibrium constant of the corresponding activated carbon gradually increases with the decrease of reaction system pressure.
基金financially supported by the China Ocean Mineral Resource Research and Development Association (No. DY125-15-T-08)the National Key Technology Research and Development Program of China (No. 2012BAB07B05)+1 种基金the National High Technology Research and Development Program of China (No. 2012AA062401)the National Natural Science Foundation of China (Nos. 21176242 and 21176026)
文摘Manganese （Mn） leaching and recovery from low-grade pyrolusite ore were studied using sulfiaric acid （H2SO4） as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were inves- tigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H2SO4 using a liq- uid/solid ratio of 6.0 mL/g for 90min at 90℃. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.
文摘In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fungi with sufficient cellulose, hemicellulose and lignin and a small amount of nitrogen, phosphorus, potassium, calcium, magnesium, other mineral salts, and some vitamins for the growth of edible fungi. However, the Pinus massoniana wood contained a significant amount of terpenoids, which are detrimental to the growth of edible fungus and mycelial. The major and current detoxification methods for Pinus massoniana sawdust were analyzed, such as steaming method, distillation method, lime water immersion method, outdoor piling fermentation method, and chemical method. Their advantages and disadvantages were discussed and reviewed. Finally, the major issues in the application of Pinus massoniana sawdust as the cultivation substrate of edible fungi were analyzed, and the application prospect of Pinus massoniana sawdust as the substrate for the cultivation of edible fungi was also reviewed.
文摘This study investigated the effects of sawdust as a soil amendment on certain growth parameters of Solanum esculentum Linn. grown in soil polluted with various concentrations of waste engine oil, and changes in the physicochemical proper- ties of the soil. The purpose was to assess the soil remediation potentials of sawdust in waste engine oil-polluted soil. The experiment was divided into three regimes： control （air-dried soil without waste engine oil and with clean sawdust）, pol- luted （waste engine oil-contaminated soil）, and amended （oil-polluted soil amended with sawdust）. Enough 3-kg soil samples were sieved and air-dried to prepare five treatment levels of waste engine oil-contaminated soil （30 mL, 1%; 60 mL, 2%; 90 mL, 3%; 120 mL, 4%; and 150 mL, 5%）, as well as five additional treatment levels （the same amounts ofoil contamination） in soil amended with sawdust. The treatment levels were replicated five times in a completely randomized design. A nursery bed was planted with a hybrid tomato variety （Roma V F） obtained from National Horticultural Research Institute （NIHORT） in Ibadan, Nigeria. During the maturation period, the growth parameters such as plant height, number of leaves, and number of branches per plant were determined and then the harvested plants were oven dried at 70 ℃for 48 hours to determine their dry weights. The effects of the sawdust amendment on the soil were assessed by determining the soil pH （glass electrode pH meter）, total nitrogen （Kjeldahl method）, total phosphorus （Bray-1 solution）, and potassium （on the leacheate by a flame photometer）. Chromium, lead, and cadmium contents were determined using an atomic absorption spectrophotometer. Analysis of variance and a Duncan multiple-range test were employed to test significant differences in the soil properties of the three regimes. The growth performance ofSolanum esculentum Linn. in the amended regime （soil with sawdust） at the 150-mL waste engine oil-contamination level was significantly higher than in the polluted regime （soil without sawdust）. After plant harvest, the pH of the soil was shown to be clearly affected by the addition of waste engine oil. The control soil （air-dried only, no sawdust, no oil） had the highest pH value, 6.60, which was significantly different from the pH values at other levels of waste engine oil contamination. However, when amended with sawdust, the control soil had a significantly lower pH value than the unamended control soil. This study further demonstrates that sawdust has the potential of amending waste engine oil-contaminated soil for increasing tomato growth performance because it is capable of increasing the soil nutrient content and reducing the soil total hydrocarbon content.
文摘Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.
文摘This work studied the effects of firing temperatures on the refractory properties of insulating firebricks produced from a blend of hydrometallurgically purified clay, high alumina cement and sawdust. Twenty grams out of a bulk (1000 Kg) of clay obtained from Ipetumodu in Nigeria was analyzed for size range, consequent upon which the remaining bulk was sieved to 100 μm, being the average size. The bulk was there after leached under a predetermined condition (1.6 mol/dm3 of oxalic acid at 70oC for 150 min and 200 rev/min agitation speed) and cylindrical samples (5 cm diameter by 5 cm high) containing different quantities of high alumina cement (5% - 20%) and sawdust (1% - 5%) were prepared, dried at 110oC and subsequently fired at 900oC, 1100oC, 1300oC and 1500oC, at the rate of 4oC/min and soaked for 2 hrs. These samples were subjected to different refractory tests (permanent linear change, modulus of rupture, bulk density, cold crushing strength and apparent porosity). Even though samples containing more than 20% alumina crumbled at elevated temperatures, it was still observed that the bricks performed to expectations at lower alumina contents, even at 1500oC. The sample containing 3% sawdust and 10% alumina cement however, gave the desired requirement for preparing good insulating firebricks with reliable phase integrity, as revealed by scanning electron microscopy (SEM).
文摘This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium and high density timber species. Particle sizes of maize cobs and sawdust used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (Sawdust:maize cobs). Briquettes were produced at room temperature (28°C) using compacting pressures 20, 30, 40 and 50 MPa. The results suggested that combining maize cob particles with sawdust of low, medium and high density wood species could significantly enhance the relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from agricultural biomass residue like maize cobs. The results further indicated that the physical and mechanical characteristics of briquettes produced from combinations of sawdust of low density species and maize cobs were exceptionally higher than that produced from combinations of maize cob particles, and medium density and high density timber species. The R2 values for the regression model between the independent variables (mixing percentage and compacting pressure) and relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from combinations of maize cob particles and sawdust of low density species (Ceiba pentandra) were 0.966, 0.932 and 0.710 respectively. This study provides a hope for briquetting maize cobs at room temperature using a low compacting pressure.
基金supported by the National Natural Science Foundation of China(22078225)the Natural Science Foundation of Zhejiang Province(LGF22E080025 and LHY22E080005)。
文摘The effects of sulfuric acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust were investigated in this study.Sulfuric acid could act as an acidic catalyst to depolymerize holocellulose through cleavage of the glycosidic bonds,the dissociation energies of which were supplied by the impact of a ball on pine sawdust,during milling.The destruction of glycosidic and hydrogen bonds in pine sawdust resulted in a decrease of crystallinity and an increase of water solubility.The sulfuric acid could promote the hydrolysis of holocellulose and its hydrolysis products.It also destroyed the chemical linkages between holocellulose and lignin during ball milling.The cleavage of chemical linkages with holocellulose made lignin more difficult to hydrolyze in subcritical water,and higher activation energy was needed to hydrolyze pretreated pine sawdust at higher reaction temperatures.It also led to the formation of glucose char and aromatic-linked polymer char from the hydrolysis products of holocellulose.
文摘In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.
文摘Many timber producing countries generate more than 2 million m3 of sawdust annually. In developing countries, sawdust is often disposed of by open dumping, open burning, or dumping in landfills. This poses huge environmental challenges related to air pollution, greenhouse gas emissions, and destruction of plant and aquatic life. Findings from this review article reveal that sawdust can be used to make sawdust construction composites with good modulus of elasticity, water absorption and strength characteristics that satisfy international specifications. These composites include particleboards, sawdust concrete blocks or bricks and sawdust concrete. The article concludes that partially replacing 5% to 17% of sand with sawdust, or replacing cement with sawdust ash in proportions of 5% to 15% in concrete mixes can produce structural concrete with compressive strengths greater than 20 MPa. Partially replacing 10% to 30% of sand used in the manufacture blocks and bricks with sawdust can also produce sawdust bricks and blocks with compressive strengths greater than 3 MPa. Sawdust composites are also attractive for their low thermal conductivity, high sound absorption and good sound insulation characteristics. These findings indicate that increased utilisation of sawdust composites in construction will mitigate against potential sawdust environmental pollution, conserve energy and reduce disposal costs.
文摘The thermodynamics and sorption efficiencies for the remediation of Cr, Ni and Cd from their aqueous solutions using Maize Cob (MC) and Sawdust (SD) in a batch system are reported. Efficiencies were judged based on parameters such as sorbent weight, initial adsorbate loading concentration, pH and surface area. Shimadzu AA650 Double Beam Atomic Absorption/Flame spectrophotometer was employed to study concentration differences before and after the adsorption process. Parameters such as ΔH, ΔS and ΔG were determined. On MC, ΔH varied as 1466.59, 1271.21 and 1347.70kJmol-1 for Cr, Ni and Cd respectively. While on SD it varied as -566.85, 256.32 and 888.77kJmol-1respectively for the same order of metal ions. The three ions were found to be chemisorbed onto MC, while on SD Cr and Ni were physisorbed and Cd remains chemisorbed as suggested by Freundlich isotherm.
文摘Sawdust which is basically considered as?a timber-industrial waste?that pollutes the environment can become a valuable commodity which is considered in three ways: Manufacturing, Energy and Agricultural utilization. The sawdust is burnt in an updraft gasifier under a limited supply of air to obtain?producer gas which is carbon II oxide and hydrogen as main components. The sawdust and other biomass materials are mixed in certain proportions, then bound together and palletized to a small blocks called briquettes. The material?was also considered to be composted by mixing it with animal digestion or?wood ashes and calcium carbonate to form fertilizers. The sawdust and wood shavings can be used for particle board as well as oil production.
文摘Whereas the pulp and paper industrial sector—considered the second highest consumer of freshwater in Europe—has already been provided with sufficient wastewater characterization and treatment technologies, other wood-based industries (e.g. furniture, floor production), which do not use water for manufacturing processes, generate different wastewater streams after: 1) cleaning/washing of machinery that applies adhesives and coatings onto wood surfaces;2) cleaning/washing of machinery that applies specific products for the curing phase of adhesives;3) cleaning/washing of sharp planar blades used for the sawn process and to prepare wood surfaces for the adhesive application;4) cleaning/washing of the floor;5) cleaning/washing of trucks and vehicles. The dilution of low-volumes of highly polluted wastewater is not acceptable any longer since conventional treatment plants are not designed for these types of industrial wastewater. There is a need for proper characterization, treatability studies, designing and testing alternative small size and cost-effective treatment systems for on-site implementation. Treatment systems based on sorption mechanisms are flexible, easy to operate and generate less sludge and several low-cost sorbents generated by forestry activities have advantageous physico-chemical characteristics. The current paper presents the preliminary results from a pilot treatment system consisting of an equalization tank, settling/sedimentation and two sorption reactors in parallel using Pinus sylvestris sawdust as sorbent implemented as part of an integrated water management plan in a wood-floor industry. The simple to operate and cost-effective pilot treatment system performs satisfactorily during an initial period of operation. The study shows an average 39% - 54% reduction of TPH;17% - 38% reduction of oil;2% - 15% of reduction of COD and;11% - 74% reduction of most toxic metals but for Co, Ni and Zn in the system B. Based on these results, Pinus sylvestris sawdust is a potential low-cost and abundant material to be considered for industrial wastewater treatment plants.
文摘In this research, composites based on treated tropical sawdust and polypropylene (PP) were prepared using hot press molding machine. Raw sawdust was chemically treated with monomer, 2 - ethylhexyl methacrylate in order to improve the mechanical properties of the composites. The influence of the chemically treated sawdust on the physical and mechanical properties of sawdust-PP composites were investigated at various loading level from 10 wt.% up to 30 wt.%. Results indicate that the mechanical properties of the chemically treated sawdust–PP composites were found to be higher than those of the raw ones respectively. The surface morphology obtained from scanning electron microscopy (SEM) showed that raw sawdust–PP composites possess surface roughness and weak interfacial adhesion between the matrix and the filler while the chemically treated one showed improved filler–matrix interaction. This indicates that better dispersion of the filler with the PP matrix has occurred upon chemical treatment of the filler. Water absorption tests showed that composites prepared from the chemically treated sawdust absorb lower amount of water compared to the ones prepared from raw sawdust, suggesting that hydrophilic nature of the cellulose in the sawdust has significantly decreased upon chemical treatment.
