Papers by Keyword: Ion Exchange Membrane

Abstract: Adoption of desalination technologies to produce fresh water in developing countries remains underutilized due to the substantial energy consumption, high operational costs, and membrane fouling associated with conventional methods. Microbial desalination cells (MDCs) have emerged as a promising alternative, offering simultaneous wastewater treatment, bioelectricity generation, and salt removal. This study aimed to evaluate the bio-templating of copper and zinc oxide nanoparticles on waste-derived eggshell membranes (CZ-ESM) and subsequently incorporated into ion exchange membranes (IEMs) for MDC applications. Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) confirmed the presence of calcinated CZ-ESM in the IEMs. The modified and control IEMs were compared based on water uptake, mechanical strength, biofouling resistance, and salt removal. Incorporation of calcinated CZ-ESM nanocomposites enhanced membrane hydrophilicity, reflected in increased water uptake while also exhibiting reduced microbial colonization, thereby improving anti-fouling performance. However, the addition of calcinated CZ-ESM nanocomposites resulted in decreased tensile strength due to nanocomposite aggregation and heterogeneous resin distribution. Modification of the IEMs showed statistically the same salt removal as that of the unmodified counterpart. These findings demonstrate the use of CZ-ESM nanocomposites as fillers for MDC membranes, highlighting their ability to enhance hydrophilicity and antifouling properties, but improvements in the mechanical properties and salt removal must be further investigated to address practical limitations in the MDC application.

Abstract: A new technology called microbial desalination cell (MDC) approaches a comprehensive way to design an innovative system for removal of organic matter and dissolved solids from wastewater. In this study, two laboratory scale MDCs having three chambered (3C-MDC) and five chambered (5C-MDC) configuration were developed for integrated biodegradation of steel plant wastewater. The 3C-MDC have anodic, middle desalination and cathodic chamber; while 5C-MDC have anodic, cathodic, middle desalination and two concentrate chambers separated by ion exchange membranes. Using synthetic saline water with 8 and 30 g/L of TDS and steel plant wastewater (3.74 g TDS/L) in desalination chamber, the TDS removal of 64 ± 2.3%, 75 ± 1.8%, and 58 ± 1.3% were observed in 3C-MDC, while in 5C-MDC, those were 58 ± 1.5%, 71 ± 2.1%, and 64 ± 2.4%, respectively in 96 h of fed batch operation. With 30 g/L of TDS concentration, the power generation observed in 3C-MDC and 5C-MDCs were (81 mW/m² and 78 mW/m²) higher than the power observed with 8 g/L (56 mW/m² and 45 mW/m²). However, with steel plant wastewater in desalination chamber the power density increased to 76 mW/m² in 5C-MDC and significantly decreased to 39 mW/m² in 3C-MDC.

Abstract: The removal of Cu2+ in water via an ion-exchange membrane under no external voltage condition was studied in the research, and effects such as Cu2+ concentration, concentration of compensation potassium ions, water stirring speed, temperature and hydraulic retention time (HRT) on the removal efficiency of Cu2+ were also investigated. The results showed that when the initial concentration of bivalent ion Cu2+ was 0.0787mmol/L （5mg/L）, under the experimental conditions of the water temperature at 25 °C , the HRT was 6h, the hydraulic mixing speed was 600±25rpm, and the concentration of the compensation ion K+ was 10 times as that of Cu2+, and the removal efficiency of Cu2+ could be achieved 85%. In addition, using the same equipments, when the inlet concentration of Cu2+ increased to 0.787mmol/L (50mg/L), the removal efficiency would be decreased to 76%; while the ratio of concentration of compensation potassium ions to that of inlet Cu2+ is larger than 20, the removal efficiency would not change significantly as the ratio continued increasing; the removal efficiency would be decreased to 60% when lowering the stirring speed to 300±25rpm; the removal efficiency would be decreased to 68% when lowering the temperature to 15+1 °C; the removal rate was no significant change when the hydraulic retention time (HRT) from 6h to 12h.

Abstract: A lab-made static electrodialysis (ED) unit was used to study the effect of oil and HPAM on the desalination process by electrodialysis. To do so, various kinds of wastewater samples were prepared to simulate the polymer flooding saltwater treated by ultrafiltration. The demineralization process and the fouling of the ion-exchange membranes could be studied by comparing the removal rates of salt by the desalination processes under different experimental conditions. Results showed that effect of oil on the desalination processes by electrodialysis was quite minor, while the polymer in simulated saltwater has much more effect on the desalination process, indicating serious fouling of ion-exchange membranes caused by HPAM.

Abstract: The aim of the present work was to study the effect of properties of ion exchange membrane on separation performance of electrodeionization (EDI) process for removal of nickel ions from dilute heavy metal solutions. It was shown that the properties of ion exchange membrane had a significant effect on removal of nickel ions. With feed water containing nickel ions at the concentration of 55mg•L^-1, the nickel ions concentration of dilute stream was lower than 0.5mg•L^-1 and the nickel rejection was greater than 99% when using EDI membranes, while that was in the range of 2.48-3.55mg•L^-1 with conventional heterogeneous ion exchange membranes. With optimum ion exchange material and operating conditions, EDI would be a very interesting and innovative technology for the treatment of dilute heavy metal solutions.

Abstract: It is a method of preparing hypophosphorous acid with electrodialysis. It comprises Ti-PbO2 anode, an insoluble cathode and an aqueous solution of hypophosphite anions in six-compartment electrolytic cell. The direct current, through the insoluble anode to cathode in electrical contact with the aqueous solution to generate H+, forms hypophosphorous acid solution. In this paper, the best term of different factors about the experiment was studied. The best condition was to keep the NaH2PO2 concentration between 300 and 500g/L, current value 3.0A, reaction time 12-18 h. The process is simple, low cost and highly efficient, which is a cleaner production without waste residue and waste water.

Abstract: The hypophosphorous acid was achieved with the electrodialysis, which comprises a Ti-PbO2 anode, a stainless steel cathode and an aqueous solution of sodium hypophosphite. The process of producing hypophosphorous acid was studied. Some factors, such as anodic voltage, product concentration and current efficiency were conducted. The results showed that, six-compartment electrodialytic cell could be used to improve the hypophosphorous acid content and purity. The Ti-PbO2 electrode was optimal anode material to cut down the cost of production. The process was simple, low cost and high efficient, and it was a cleaner production without waste residue and waste water.