Toute reproduction ou représentation intégrale ou partielle, par quelque procédé que ce soit, des... more Toute reproduction ou représentation intégrale ou partielle, par quelque procédé que ce soit, des pages publiées dans le présent ouvrage, faite sans l'autorisation de l'éditeur est illicite et constitue une contrefaçon. Seules sont autorisées, d'une part, les reproductions strictement réservées à l'usage privé du copiste et non destinées à une utilisation collective et, d'autre part, les analyses et courtes citations justifiées par le caractère scientifique ou d'information de l'oeuvre dans laquelle elles sont incorporées (Loi du 1 er juillet 1992-art. L 122-4 et L 122-5, et Code pénal art. 425).
In this paper, the technical capabilities of a lab-scale electrodeionization (EDI) process and it... more In this paper, the technical capabilities of a lab-scale electrodeionization (EDI) process and its basic technology electrodialysis (ED) process that used for removing NO3 – from nitrate-contaminated groundwater were investigated. The EDI unit with three chambers (anode, diluted and cathode) was used; it utilized electricity to regenerate ion-exchange resins instead of chemicals. At first, the voltage-current (V-I) characteristic curves about the ED and EDI processes were studied, and then chose the optimum operating voltage which based on the curves. The effects of operational parameters (voltage, water flow rate and initial NO3 –-N concentration) on nitrate removal rate and concentration effect of ED and different ion-exchange resins, the proportion of anion and cation resins and the voltage used for regeneration of EDI were investigated. The results of ED showed that NO3 –-N concentration could be reduced from initial 50–300 mg/l to 1–6 mg/l, with the removal rate 99% and the conductivity could be reduced to less than 10 µs/ cm. Under the conditions of equal (1–8 l/h) and unequal (1:1,2,3,4,5,6,7,8 l/h) water flow rate between concentrated and diluted water, the concentrated water could be reached to 2–5 times more than the initial water. The current efficiency and energy consumption was 17–34% and – 0.–1.7 W•h/l, respectively. It was shown that ED was effective to NO3 removal and concentration. As to EDI process, the results showed that continuous electrodeionization could regenerate the resins effectively from simulated nitrate-contaminated water. Under the condition of 50 V as the regenerate voltage, after 90 h, the regeneration rate was as high as 60%. In addition, the NO3 –-N concentration of the diluted water was reduced to 5 mg/l from initial 50 mg/l. As a fundamental technology of in-situ remediation for groundwater contamination, the process was proved to be feasible and provided foundation for further research.
In this paper, a laboratory-scale process which combined electrolysis (EL) and electrodialysis (E... more In this paper, a laboratory-scale process which combined electrolysis (EL) and electrodialysis (ED) was developed to treat copper-containing wastewater. The feasibility of such process for copper recovery as well as water reuse was determined. Effects of three operating parameters, voltage, initial Cu 2+ concentration and water flux on the recovery of copper and water were investigated and optimized. The results showed that about 82% of copper could be recovered from high concentration wastewater (HCW, >400 mg/L) by EL, at the optimal conditions of voltage 2.5 V/cm and water flux 4 L/h; while 50% of diluted water could be recycled from low concentration wastewater (LCW, <200 mg/L) by ED, at the optimal conditions of voltage 40 V and water flux 4 L/h. However, because of the limitation of energy consumption (EC), LCW for EL and HCW for ED could not be treated effectively, and the effluent water of EL and concentrated water of ED should be further treated before discharged. Therefore, the combination process of EL and ED was developed to realize the recovery of copper and water simultaneously from both HCW and LCW. The results of the EL-ED process showed that almost 99.5% of copper and 100% of water could be recovered, with the energy consumption of EL ≈3 kW h/kg and ED ≈2 kW h/m 3 . According to SEM and EDX analysis, the purity of recovered copper was as high as 97.9%.
Toute reproduction ou représentation intégrale ou partielle, par quelque procédé que ce soit, des... more Toute reproduction ou représentation intégrale ou partielle, par quelque procédé que ce soit, des pages publiées dans le présent ouvrage, faite sans l'autorisation de l'éditeur est illicite et constitue une contrefaçon. Seules sont autorisées, d'une part, les reproductions strictement réservées à l'usage privé du copiste et non destinées à une utilisation collective et, d'autre part, les analyses et courtes citations justifiées par le caractère scientifique ou d'information de l'oeuvre dans laquelle elles sont incorporées (Loi du 1 er juillet 1992-art. L 122-4 et L 122-5, et Code pénal art. 425).
In this paper, the technical capabilities of a lab-scale electrodeionization (EDI) process and it... more In this paper, the technical capabilities of a lab-scale electrodeionization (EDI) process and its basic technology electrodialysis (ED) process that used for removing NO3 – from nitrate-contaminated groundwater were investigated. The EDI unit with three chambers (anode, diluted and cathode) was used; it utilized electricity to regenerate ion-exchange resins instead of chemicals. At first, the voltage-current (V-I) characteristic curves about the ED and EDI processes were studied, and then chose the optimum operating voltage which based on the curves. The effects of operational parameters (voltage, water flow rate and initial NO3 –-N concentration) on nitrate removal rate and concentration effect of ED and different ion-exchange resins, the proportion of anion and cation resins and the voltage used for regeneration of EDI were investigated. The results of ED showed that NO3 –-N concentration could be reduced from initial 50–300 mg/l to 1–6 mg/l, with the removal rate 99% and the conductivity could be reduced to less than 10 µs/ cm. Under the conditions of equal (1–8 l/h) and unequal (1:1,2,3,4,5,6,7,8 l/h) water flow rate between concentrated and diluted water, the concentrated water could be reached to 2–5 times more than the initial water. The current efficiency and energy consumption was 17–34% and – 0.–1.7 W•h/l, respectively. It was shown that ED was effective to NO3 removal and concentration. As to EDI process, the results showed that continuous electrodeionization could regenerate the resins effectively from simulated nitrate-contaminated water. Under the condition of 50 V as the regenerate voltage, after 90 h, the regeneration rate was as high as 60%. In addition, the NO3 –-N concentration of the diluted water was reduced to 5 mg/l from initial 50 mg/l. As a fundamental technology of in-situ remediation for groundwater contamination, the process was proved to be feasible and provided foundation for further research.
In this paper, a laboratory-scale process which combined electrolysis (EL) and electrodialysis (E... more In this paper, a laboratory-scale process which combined electrolysis (EL) and electrodialysis (ED) was developed to treat copper-containing wastewater. The feasibility of such process for copper recovery as well as water reuse was determined. Effects of three operating parameters, voltage, initial Cu 2+ concentration and water flux on the recovery of copper and water were investigated and optimized. The results showed that about 82% of copper could be recovered from high concentration wastewater (HCW, >400 mg/L) by EL, at the optimal conditions of voltage 2.5 V/cm and water flux 4 L/h; while 50% of diluted water could be recycled from low concentration wastewater (LCW, <200 mg/L) by ED, at the optimal conditions of voltage 40 V and water flux 4 L/h. However, because of the limitation of energy consumption (EC), LCW for EL and HCW for ED could not be treated effectively, and the effluent water of EL and concentrated water of ED should be further treated before discharged. Therefore, the combination process of EL and ED was developed to realize the recovery of copper and water simultaneously from both HCW and LCW. The results of the EL-ED process showed that almost 99.5% of copper and 100% of water could be recovered, with the energy consumption of EL ≈3 kW h/kg and ED ≈2 kW h/m 3 . According to SEM and EDX analysis, the purity of recovered copper was as high as 97.9%.
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