The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation ...The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase (MnP) decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 μg/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78,9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 μg H202/L was superadded respectively together with 200 mg dye/L.展开更多
In this study, two polymeric resins with different pore sizes were synthesized to study comparative adsorption of reactive black KNB dye. Styrene-divinylbenzene copolymer resin NG-8 has an average pore size of 3.82 nm...In this study, two polymeric resins with different pore sizes were synthesized to study comparative adsorption of reactive black KNB dye. Styrene-divinylbenzene copolymer resin NG-8 has an average pore size of 3.82 nm, about half of that of polydivinylbenzene resin NG-7 (6.90 nm). NG-8 also has a surface acidity about 4 times that of NG-7, resulting in a much more negative surface of the former resin as compared to the latter at pH 6.05. Equilibrium adsorption of KNB was significantly influenced by the surface functionality of the resins, as evidenced by the observations that NG-8 adsorbed constantly less KNB than NG-7 and that the presence of CaCl2 enhanced the adsorption by both resins. The intra-particle diffusion appears to be the primary rate-limiting process. While the pores of both resins are accessible to KNB, the slower adsorption by NG-8 than by NG-7 suggests that the smaller pores of NG-8 further retard the intra-particle diffusion of KNB.展开更多
A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamin...A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamines(labeled Dipip)were characterized using 13C solidstate NMR,FTIR,TGA,DSC,XRD,SEM and EDX.The adsorptive performances of the synthesized polymers for Erichrome Black T(EBT)uptake from aqueous solution were investigated under batch process.Equilibrium,kinetic,and thermodynamic studies were conducted to determine the influence of different operational parameters of the adsorption process.The two most promising polymers among the series show an excellent EBT removal efficiency of~100%and~95%with high adsorption capacities of 775 mgg 1 and 917 mgg 1,respectively at a meager dosage of 5 mg.The sorption of EBT on the polymers was well described by RedlichPeterson&Langmuir model while the kinetic studies indicate that pseudosecond order model was followed.For the thermodynamic studies,the negative AG and positive AH values obtained suggest a spontaneity of the sorption process which was endothermic in nature.The results of reusability test of the resins were promising even at the fourth cycle,showcasing the potentials of the new polymers in dyes contaminated water treatment.展开更多
In this work a novel anode configuration consisting of an iron mesh double layer is proposed for the electrochemical treatment of wastewater. The removal of Reactive Black 5 dye(RB5) from synthetic contaminated wate...In this work a novel anode configuration consisting of an iron mesh double layer is proposed for the electrochemical treatment of wastewater. The removal of Reactive Black 5 dye(RB5) from synthetic contaminated water was used as a model system. At a constant anode surface area, identical process operating parameters and batch process mode, the iron mesh double layer electrode showed better performance compared to the conventional single layer iron mesh. The double layer electrode was characterized by RB5 and chemical oxygen demand(COD) removal efficiency of 98.2% and 97.7%, respectively, kinetic rate constant of 0.0385/min, diffusion coefficient of 4.9 × 10^(-5)cm^2/sec and electrical energy consumption of 20.53 kWh/kgdye removed. In the continuous flow system, the optimum conditions suggested by Response Surface Methodology(RSM) are: initial solution p H of 6.29,current density of 1.6 m A/cm^2, electrolyte dose of 0.15 g/L and flow rate of 11.47 m L/min which resulted in an RB5 removal efficiency of 81.62%.展开更多
基金This work was supported by the Program for New Century Excellent Talents in University in China(No.NCET-05-0612)the National Natural Science Foundation of China(No.20677014).
文摘The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase (MnP) decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 μg/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78,9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 μg H202/L was superadded respectively together with 200 mg dye/L.
基金This work was financially support by the State Key Laboratory of Pollution Control and Resources Reuse, China (Tongji University, Grant PCRRF 05003).
文摘In this study, two polymeric resins with different pore sizes were synthesized to study comparative adsorption of reactive black KNB dye. Styrene-divinylbenzene copolymer resin NG-8 has an average pore size of 3.82 nm, about half of that of polydivinylbenzene resin NG-7 (6.90 nm). NG-8 also has a surface acidity about 4 times that of NG-7, resulting in a much more negative surface of the former resin as compared to the latter at pH 6.05. Equilibrium adsorption of KNB was significantly influenced by the surface functionality of the resins, as evidenced by the observations that NG-8 adsorbed constantly less KNB than NG-7 and that the presence of CaCl2 enhanced the adsorption by both resins. The intra-particle diffusion appears to be the primary rate-limiting process. While the pores of both resins are accessible to KNB, the slower adsorption by NG-8 than by NG-7 suggests that the smaller pores of NG-8 further retard the intra-particle diffusion of KNB.
基金Imam Abdulrahman Bin Faisal University(IAU),Dammam for providing research facilities.
文摘A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamines(labeled Dipip)were characterized using 13C solidstate NMR,FTIR,TGA,DSC,XRD,SEM and EDX.The adsorptive performances of the synthesized polymers for Erichrome Black T(EBT)uptake from aqueous solution were investigated under batch process.Equilibrium,kinetic,and thermodynamic studies were conducted to determine the influence of different operational parameters of the adsorption process.The two most promising polymers among the series show an excellent EBT removal efficiency of~100%and~95%with high adsorption capacities of 775 mgg 1 and 917 mgg 1,respectively at a meager dosage of 5 mg.The sorption of EBT on the polymers was well described by RedlichPeterson&Langmuir model while the kinetic studies indicate that pseudosecond order model was followed.For the thermodynamic studies,the negative AG and positive AH values obtained suggest a spontaneity of the sorption process which was endothermic in nature.The results of reusability test of the resins were promising even at the fourth cycle,showcasing the potentials of the new polymers in dyes contaminated water treatment.
基金the financial support provided by the High Impact Research Grant UM.C/HIR/MOHE/ENG/43the Bright Sparks Program which made this research possible
文摘In this work a novel anode configuration consisting of an iron mesh double layer is proposed for the electrochemical treatment of wastewater. The removal of Reactive Black 5 dye(RB5) from synthetic contaminated water was used as a model system. At a constant anode surface area, identical process operating parameters and batch process mode, the iron mesh double layer electrode showed better performance compared to the conventional single layer iron mesh. The double layer electrode was characterized by RB5 and chemical oxygen demand(COD) removal efficiency of 98.2% and 97.7%, respectively, kinetic rate constant of 0.0385/min, diffusion coefficient of 4.9 × 10^(-5)cm^2/sec and electrical energy consumption of 20.53 kWh/kgdye removed. In the continuous flow system, the optimum conditions suggested by Response Surface Methodology(RSM) are: initial solution p H of 6.29,current density of 1.6 m A/cm^2, electrolyte dose of 0.15 g/L and flow rate of 11.47 m L/min which resulted in an RB5 removal efficiency of 81.62%.