Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggr...Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellar complex.With addition of surfactant,the conformation of polyion chain changes from stretched to random coiled to spherical,and at the same time more free micelles are formed by surfactants in mixtures.Increasing the length of spacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble.The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini sur- factant.展开更多
The two types of biological consortia--real activated sludge and laboratory adapted consortium were immobilized in polyethylene oxide cryogels. Their potential to decolorize the anionic azo dye amaranth in sequencing ...The two types of biological consortia--real activated sludge and laboratory adapted consortium were immobilized in polyethylene oxide cryogels. Their potential to decolorize the anionic azo dye amaranth in sequencing batch biofilters was studied. At a growing concentration of azo dye （20 mg·L^-1, 25 mg·L^-1, 30 mg·L^-1） the biofilters had a mean feeding rate of 30.32 ± 25.78 mL^-1·h^-1 and 13.76 ：t： 8.33 mL^-1·h^-1, respectively for immobilized adapted consortia （AC） and activated sludge （AS）. The AC-biofilter reached an overall decolorization rate of 0.211 ± 0.14 mg dye.mLLh1 and a decolorization effectiveness of 60.28 ：t： 32.42%. In contrast, the mean values for overall decolorization rate and effectiveness in AS-biofilter were 0.249 ± 0.16 mg dye.mL^-1·h^-1 and 82.48± 14.41%. The system with immobilized activated sludge had more stable process dynamics and higher tolerance to shock azo dye loading in the first stage of the process. The immobilized adapted consortium presented a good ability to adequate response at higher azo dye concentrations and loading.展开更多
基金Supported by the National Natural Science Foundation of China （No.20476025）, the Doctoral Research Foundation of the Ministry of Education of China （No.20050251004）, E-institute of Shanghai High Institution Grid （No.200303） and Shanghai Municipal Science and Technology Commission of China （No.05DJ14002）.
文摘Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellar complex.With addition of surfactant,the conformation of polyion chain changes from stretched to random coiled to spherical,and at the same time more free micelles are formed by surfactants in mixtures.Increasing the length of spacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble.The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini sur- factant.
文摘The two types of biological consortia--real activated sludge and laboratory adapted consortium were immobilized in polyethylene oxide cryogels. Their potential to decolorize the anionic azo dye amaranth in sequencing batch biofilters was studied. At a growing concentration of azo dye （20 mg·L^-1, 25 mg·L^-1, 30 mg·L^-1） the biofilters had a mean feeding rate of 30.32 ± 25.78 mL^-1·h^-1 and 13.76 ：t： 8.33 mL^-1·h^-1, respectively for immobilized adapted consortia （AC） and activated sludge （AS）. The AC-biofilter reached an overall decolorization rate of 0.211 ± 0.14 mg dye.mLLh1 and a decolorization effectiveness of 60.28 ：t： 32.42%. In contrast, the mean values for overall decolorization rate and effectiveness in AS-biofilter were 0.249 ± 0.16 mg dye.mL^-1·h^-1 and 82.48± 14.41%. The system with immobilized activated sludge had more stable process dynamics and higher tolerance to shock azo dye loading in the first stage of the process. The immobilized adapted consortium presented a good ability to adequate response at higher azo dye concentrations and loading.
