研究了NaOH-H2O2组成的碱溶剂体系对玉米秸秆的溶解规律,并结合酸沉、醇析方法分离出了3种主要成分,研究了过氧化氢浓度、pH、液固比、温度、时间对玉米秸秆组分分离过程的影响。结果表明:碱溶剂处理后的剩余固体物质是纤维素和不溶物,...研究了NaOH-H2O2组成的碱溶剂体系对玉米秸秆的溶解规律,并结合酸沉、醇析方法分离出了3种主要成分,研究了过氧化氢浓度、pH、液固比、温度、时间对玉米秸秆组分分离过程的影响。结果表明:碱溶剂处理后的剩余固体物质是纤维素和不溶物,滤液经酸沉后的固体为木质素,酸沉后的滤液调pH后醇析所得的固体为半纤维素。试验确定了分离过程的最佳工艺条件:过氧化氢浓度5%,pH=12,反应时间3 h,溶解温度60℃,液固比30 m L/g。在此条件下,纤维素回收率84.2%,木质素回收率为66.6%,半纤维素回收率96.7%,滤液经4次循环使用,纤维素回收率82.7%,木质素回收率67.6%,半纤维素回收率97.4%。碱处理及酸沉、醇析后剩余固体的结构分析证明了此方法的可行性。展开更多
Both activity and stability of the catalyst can be improved in heterogeneous Fenton reaction,in particular,with no limitation for the working p H and no production of the sludge.In this work,a combination of catalyst ...Both activity and stability of the catalyst can be improved in heterogeneous Fenton reaction,in particular,with no limitation for the working p H and no production of the sludge.In this work,a combination of catalyst Cu_2O and pore-channel-dispersed H_2O_2is proposed to treat the pulp wastewater.Degradation degree of CODs in the wastewater was up to 77%in the ceramic membrane reactor using Cu_2O powder(2.0 g·L^(-1))and membranefeeding H_2O_2(0.8 ml·L^(-1))within 60 min.Evolution of·OH radical formation in the advanced oxidation process was analyzed with a fluorescent method.Utilization efficiency of H_2O_2was successfully enhanced by 10%with the membrane distributor.Further on,the catalyst recyclability was evaluated in a five-cycle test.The concentration of copper ions being dissolved in the treated water was monitored with ICP.After Cu_2O/H_2O_2(membrane)treatment the effluent is qualified to discharge with COD concentration lower than 15 mg·L^(-1)with regard to the national standard GB25467-2010.展开更多
As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Ly...As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Lyocell fiber is claimed as“green and eco-friendly fiber”with a good application prospect in the 21st century.The preparation of lyocell fiber is based on the cellu-losic non-derivative solution system,i.e.,N-methylmorpholine-N-oxide system which is nontoxic and recyclable.In this review,firstly,the demands of dissolving pulp properties for regenerated-cellulosic fiber(RCF),especially for lyocell fiber,were introduced in detail.Next,the whole manu-facturing processes including pretreatment,preparation of spinning dope,spinning,posttreatment and efficient solvent recovery technologies were reviewed emphatically.Then,the properties and structural characteristics of lyocell fiber were illustrated.At last,some suggestions were proposed for lyocell fiber development in China.展开更多
文摘研究了NaOH-H2O2组成的碱溶剂体系对玉米秸秆的溶解规律,并结合酸沉、醇析方法分离出了3种主要成分,研究了过氧化氢浓度、pH、液固比、温度、时间对玉米秸秆组分分离过程的影响。结果表明:碱溶剂处理后的剩余固体物质是纤维素和不溶物,滤液经酸沉后的固体为木质素,酸沉后的滤液调pH后醇析所得的固体为半纤维素。试验确定了分离过程的最佳工艺条件:过氧化氢浓度5%,pH=12,反应时间3 h,溶解温度60℃,液固比30 m L/g。在此条件下,纤维素回收率84.2%,木质素回收率为66.6%,半纤维素回收率96.7%,滤液经4次循环使用,纤维素回收率82.7%,木质素回收率67.6%,半纤维素回收率97.4%。碱处理及酸沉、醇析后剩余固体的结构分析证明了此方法的可行性。
基金Supported by the Prospective Research Project of Jiangsu Province(BY2014005-06)
文摘Both activity and stability of the catalyst can be improved in heterogeneous Fenton reaction,in particular,with no limitation for the working p H and no production of the sludge.In this work,a combination of catalyst Cu_2O and pore-channel-dispersed H_2O_2is proposed to treat the pulp wastewater.Degradation degree of CODs in the wastewater was up to 77%in the ceramic membrane reactor using Cu_2O powder(2.0 g·L^(-1))and membranefeeding H_2O_2(0.8 ml·L^(-1))within 60 min.Evolution of·OH radical formation in the advanced oxidation process was analyzed with a fluorescent method.Utilization efficiency of H_2O_2was successfully enhanced by 10%with the membrane distributor.Further on,the catalyst recyclability was evaluated in a five-cycle test.The concentration of copper ions being dissolved in the treated water was monitored with ICP.After Cu_2O/H_2O_2(membrane)treatment the effluent is qualified to discharge with COD concentration lower than 15 mg·L^(-1)with regard to the national standard GB25467-2010.
基金This work was financially supported by National Key Research and Development Program of China(No.2017YFB0308200 and No.2017YFE0101500).
文摘As one of the regenerated cellulosic fibers,viscose fiber has the largest output.However,the wastes produced in the manufacturing process are difficult to eliminate,which restricts the de-velopment of viscose fiber.Lyocell fiber is claimed as“green and eco-friendly fiber”with a good application prospect in the 21st century.The preparation of lyocell fiber is based on the cellu-losic non-derivative solution system,i.e.,N-methylmorpholine-N-oxide system which is nontoxic and recyclable.In this review,firstly,the demands of dissolving pulp properties for regenerated-cellulosic fiber(RCF),especially for lyocell fiber,were introduced in detail.Next,the whole manu-facturing processes including pretreatment,preparation of spinning dope,spinning,posttreatment and efficient solvent recovery technologies were reviewed emphatically.Then,the properties and structural characteristics of lyocell fiber were illustrated.At last,some suggestions were proposed for lyocell fiber development in China.
