An Insight into Electro-dialysis for Water Treatment (original) (raw)
Related papers
Electrodialysis desalination for water and wastewater: A review
Chemical Engineering Journal, 2020
The principle of electrodialysis (ED) desalination was first presented in 1890 by Maigrot and Sabates, and its development into industrial scale started for more than 50 years ago. The operation of ED is driven by the development of ion exchange membranes produces high water recovery and does not require phase change, reaction, or chemicals. These advantages provide environmental benefits without the use of fossil fuels and chemical detergents. Whilst there are a number of reviews that have attempted to optimise ED performance for various applications, ED technology still has limitations involving scaling, membrane fouling, and permselectivity. In this paper, an extensive review of current studies on the process, principles, and setups of ED technology is given to deliver a comprehensive collection of all the main findings published on this technology so far. Also, it provides an overview of the possible sustainability approaches to be integrated with the ED process. The current developments and the sustainability of ED are critically examined for in-depth knowledge of what makes ED a promising desalination for potable water production. Finally, mathematical approaches to the design of ED process are briefly mentioned.
2020
Electrodialysis was applied as a tertiary treatment for effluents from a Brazilian sewage treatment plant, and the results are discussed in terms of membrane ageing and process efficiency. Current-voltage analysis and electrodialysis (ED) treatment were performed in a bench cell. The treatment was discontinuously carried out for 930 hours within one year. During the experiments, samples were collected for evaluation, and the pH, conductivity and ion concentration were monitored. Thermogravimetric analyses of the membrane were also performed. A reduction in electrical conductivity and the high ion percentage extraction demonstrated the efficiency of the ED treatment, confirming the possibility of using ED as a tertiary treatment for sewage. ED showed 100% effectiveness in terms of meeting the quality standards established by Brazilian legislation on the discharge of effluents. Additionally, important corrosive (Cl) and encrusting ions (Ca and Mg) that limit certain industrial uses of...
Desalination, 2017
Large demands for water in industry and consumer markets have led to the development of seawater desalination plants worldwide. Electrodialysis allows the removal of ions at a much lower specific energy consumption than pressure-driven systems and holds the potential to move the desalination industry to greater water yields, lowering the degree of water wasted and energy required for separations. This study investigates the use of traditional electrodialysis as well as electrodeionization for the removal of contaminant ions from brackish water as well as samples from industrial sources. Results indicated that conventional electrodeionization can successfully remove ion contaminants from brackish water at specific energy consumptions of approximately 0.9-1.5 kWh/m 3 water recovered with high water productivity at 40-90 L/m 2 h. Ion-exchange resin wafer electrodeionization showed greater promise with specific energy consumption levels between 0.6-1.1 kWh/m 3 water recovered and productivity levels between 10-40 L/m 2 h. From these results, electrodialysis and electrodeionization have demonstrated viability as alternatives to pressure-driven membrane systems for brackish water desalination.
DESALINATION AND WATER TREATMENT
The use of domestic wastewater (DWW) in irrigation offers numerous advantages because of its nutrient compositions. However, the direct use of DWW is risky to both human health and the environment. Hence to comply with circular economy principles, designing a strategy for treating and capturing nutrients from DWW is imperative. Electrodialysis (ED) is a promising technology to achieve this objective. This study investigated the effect of pH and potential difference (voltage) on the performance of the ED. The desalination and transport fate of some nutrients on real DWW is also monitored. The ED system attained an optimum desalination performance of 0.469 mS/cm in 20 min at voltage 15 V and pH 7. Under these conditions, the system achieved 90% nitrate and nitrite removal, while phosphate removal was at 67%. Under continuous flow conditions, the system managed to concentrate the target nutrients in a subsequent chamber. The removal of some organics was also attained.
Various applications of electrodeionization (EDI) method for water treatment—A short review
Desalination, 2014
Electrodeionization (EDI), also known as continuous deionization (CDI), is a hybrid separation process combining ion-exchange resins with ion-exchange membranes. The EDI gained increasing attention for removal/recovery of ions from water. There are different types of applications for the EDI on the removal and concentration of various species from effluent streams. The aim of this paper is to give a brief overview of those studies. The presented examples of applications have shown that EDI process is very efficient in environmental protection, production of ultra pure water, and for the recovery of some valuable species. Normally, weakly-ionized species, such as carbon dioxide and boron are difficult to remove via such membrane processes as reverse osmosis and electrodialysis reversal (EDR). The EDI offers the benefit of continuous removal of these species to a very high degree. The main technological parameters determining the efficiency of an EDI module are the current strength, flow velocity in the dilute and concentrate compartments, temperature, and TDS (in both initial and purified water).
Separation of different ions from wastewater at various operating conditions using electrodialysis
Separation and Purification Technology, 2007
In this paper, effect of influential factors on separation of monovalent (Na + ), divalent (Cu 2+ , Zn 2+ , Pb 2+ ) and trivalent (Cr 3+ ) ions from wastewater was investigated. Two types of different membranes (AMV and CMV made by Asahi Glass and AR204SXR412 and CR67MK111 made by Ionics) with different ion exchange capacities (IEC) were used. Taguchi experimental design was used to plan a minimum number of experiments. A L 9 orthogonal array (OA, four factors in three levels) was employed to evaluate effect of concentration (100, 500, and 1000 ppm), temperature (25, 40, and 60 • C), flow rate (0.07, 0.7, and 1.2 mL/s) and voltage (10, 20, and 30 V) on separation percent (SP) of the individual ions in the solution. A L 16 OA (five factors in four levels) was applied to enquire the effect of ion valence in a mixture of ions on the response (SP). Statistical analysis, ANOVA, was also employed to determine the relationship between experimental conditions and yield levels. The results show that increasing concentration, voltage and temperature improves cell performance; however, SP decreases with increasing flow rate. At concentrations of more than 500 ppm, dependency of SP on concentration diminishes. The optimum levels of influential factors, determined for all ions are: concentration 1000 ppm, temperature 60 • C, flow rate 0.07 mL/s and voltage 30 V. According to the results, using a membrane pair with higher IEC improves SP. It was found that performance of an electrodialysis (ED) cell is almost independent on the type of ions and only depends on the operating conditions and the cell structure. This result was confirmed by the experiments conducted on a mixture of ions. It was also found that SP of monovalent ions is larger than divalent and trivalent ions (S Cr < S Cu , S Zn , S Pb < S Na ). For ions of similar valence, SP was found to be restricted by molecular weight and electrochemical activation energy of the ions (S Pb < S Cu < S Zn ).
Effect of an ion-exchange filler on the deionized water quality in electrodialysis
Russian Journal of Electrochemistry, 2000
Desalination channels, containing an inert separator and a monolayer of ionites AV-17 and KU-2 taken in various volume ratios, are studied while maintaining concentrations of all solution components invariant. It is shown that the composition of the ion-exchange filler of the desalination channel affects the rate of transport of salt ions through relevant membranes, pH, and specific resistance of desalinated solution. The behavior of membrane systems in an overlimiting state is explained by using notions about different mechanisms governing the so-called overlimiting current through anion-exchange and cation-exchange membranes.
Application of Electrodialysis in Waste Water Treatment and Impact of Fouling on Process Performance
Journal of Membrane Science & Technology, 2018
Electrodialysis (ED) is a new advanced separation process that is commonly utilized for producing drinking water from water bodies as well as for the treatment of industrial effluents. ED process is applied on commercial scale. Basically, an ED process consists of an ion exchange membrane and the diving force necessary for applicability of the process is electric potential. Due to the presence of electric potential ions from one solution after passing through ion selective membrane barrier are transferred to another solution. The main factors on which ED process performance depends on concentration of ion in raw water, flow rate, concentration of feed, current density, membrane properties and cell compartments geometry. Fouling which is produced by foulants including organics, colloids and biomass on the inside membrane internal structure or on the outside surface results in reduction of process separation efficiency and energy consumption is enhanced. Fouling increases the membrane resistance and selectivity of membrane is reduced by fouling. Therefore, some methods are proposed to reduce fouling in ED system such as pre-treatment of feed solution, zeta potential control, membrane properties modification and flowrate optimization. It is a need of an hour to suggest a reducing method less energy and thus minimum operating and investment cost. Electrodialysis Reversal (EDR) system can be as regarded as best option because no extra chemicals are required and life of membrane increased by it. In EDR fouling progress is broken by revering electric potential (applied electric field). This paper elaborates ED process briefly and presents an overview of literature review on different kinds of fouling mechanisms. Also, different cleaning methods have been briefly described for enhancing efficiency of ED process.