Showing papers on "Electrodeionization published in 2009"
TL;DR: In this article, a specially designed electrodeionization (EDI) stack was used for deep softening from simulated aqueous solutions containing low concentrations of hardness ions, and performances of different processes were compared under various experimental conditions of applied voltage, concentrate flow rate, and feed solution composition.
69 citations
TL;DR: In this paper, the capabilities of continuous electrodeionization process (CEDI) and its basic technologies (electrodialysis (ED) and ion exchange (IX)) were analyzed in order to remove hexavalent chromium from synthetic solutions at pH 5.
60 citations
TL;DR: In this paper, continuous electrodeionization (CEDI) was investigated for removal and recovery of Cr(VI) from synthetic wastewater, and different anion exchange resins, including the gel strong-base resin, gel weak-base resins and macro-porous strong base resins were examined.
50 citations
TL;DR: In this article, an electrodialysis (ED) cell was assembled and experiments were performed with acetic acid solution as model trace chemical in water and a real wastewater stream was also treated and results were discussed in terms of current efficiency and energy consumption.
Abstract: A study has been carried out on the possibility of recovery light carboxylic acids (C1–C6) from an acidic waste stream by means of electrodialysis (ED) technique. The starting solution has very low concentration in organic acids and low specific conductivity. The main object of the study is the identification of the critical aspects for a complete electrodeionization of the water in a scheme of water reuse as process water or boiler feed-water. Concentration and recovery of carboxylic acids from wastewater streams can be a sustainable “green” alternative to biological degradation and turn into a valuable alternative, the more the higher the possibility of reusing the concentrated organic acid stream. In this work an ED cell was assembled and experiments were performed with acetic acid solution as model trace chemical in water. A real wastewater stream was also treated and results are discussed in term of current efficiency and energy consumption.
39 citations
TL;DR: In this paper, a mathematical model for deionization of electrolyte solutions containing more than one ion and ions that are multivalent in nature is presented, and the model validity is verified by comparing the results with a few experimental observations.
Abstract: Electrodeionization (EDI) technology combines the operation principle of both ion exchange and electrodialysis in one single unit and overcomes the disadvantages of either unit. This technology has been widely used in the production of ultrapure water due to its better performance and economical operation at low feed concentrations. As a result, there have been several studies that deal with application of this technology for the removal of ions from water. However, except for a few studies, most of the reported works deal with the experimental study of EDI. This study deals with the development of a mathematical model for deionization of electrolyte solutions containing more than one ion and ions that are multivalent in nature. The model validity is verified by comparing the results with a few experimental observations. This is followed by a sensitivity study of the EDI unit to explore the effect of various operating and system parameters on the ion removing ability of the EDI unit. Consequently, a syste...
34 citations
TL;DR: In this paper, a new type of ionic and electronic current sinks made of electrode graphite powder were used as a new kind of current sinks for electrodialysis of simulated copper plating rinse water containing 100 mg L -1 Cu 2+ ions and electrodeionization of a 0.001 M CuSO4 solution with simultaneous electrochemical regeneration of the used ion exchange resin beds.
Abstract: Electrostatic shielding zones made of electrode graphite powder were used as a new type of ionic and electronic current sinks. Because of the local elimination of the applied electric field, voltage and current within the zones, ions are led inside them and accumulate there. We implemented the current sinks in electrodialysis of a simulated copper plating rinse water containing 100 mg L -1 Cu 2+ ions and electrodeionization of a 0.001 M CuSO4 solution with simultaneous electrochemical regeneration of the used ion exchange resin beds and obtained pure water with a Cu 2+ ion concentration of less than 0.12 mg L -1 at a flow rate of 1.29x10 -4 L s -1 diluate stream and a current density of 2 mA cm -2
33 citations
TL;DR: In this article, the effects of major operational variables including current density, wastewater flowrate and influent Cr(VI) concentration on the performance of continuous electrodeionization (CEDI) were investigated systematically.
31 citations
TL;DR: In this paper, a 2-compartment cell with diaphragm was found to be a suitable construction for electrochemical resin regeneration after previous discontinuous loading, and the determination of resin conductivities and transport numbers was also part of the studies.
16 citations
Patent•
02 Nov 2009TL;DR: In this paper, an on-demand system for intermittent high purity water production which by locating a storage tank for pre-polished water just prior to a final high purity polishing device reduces the potential for stagnant water in the system to reduce or degrade product high-purity water quality and reduces the actual degradation of high- purity water quality.
Abstract: An on-demand system for intermittent high purity water production which by locating a storage tank (10) for pre-polished water just prior to a final high purity polishing device reduces the potential for stagnant water in the system to reduce or degrade product high purity water quality and reduces the actual degradation of high purity water quality. Pre-polished water is preferably produced by reverse osmosis (2). Final polished water is produced by continuous electrodeionization (13).
10 citations
TL;DR: In this article, the authors constructed electrostatic shielding zones made of electrode graphite powder and used them as a new type of ionic and electronic current sinks, where ions are led inside them and accumulate there.
Abstract: We constructed electrostatic shielding zones made of electrode graphite powder and used them as a new type of ionic and electronic current sinks. Because of the local elimination of the applied electric field, voltage and current within the current sinks, ions are led inside them and accumulate there. The sinks become ion concentrating compartments whereas the adjacent compartments become ion depleting compartments. The proposed electrodeionization process uses no permselective ion exchange membranes. We implemented it in electrodialysis desalination of a synthetic brackish 0.03 M NaCl solution and obtained potable water with a NaCl concentration <500 mg L -1 . Furthermore, we performed electrodialysis of 0.002 M NiSO4 and electrodeionization of 0.001 M NiSO4 solutions with simultaneous electrochemical regeneration of the used ion exchange resin beds. By the continuous mode of electrodeionization of the 0.001 M NiSO4 solution we obtained pure water with a Ni 2+ ion concentration of less than 0.5 mg L -1 at a flow rate of 2.3 x10 -4 L s -1 diluate stream
7 citations
15 Nov 2009
TL;DR: In this paper, the application of fractional electrodeionization (FEDI) in the production of deionized water is discussed, including better quality of treated water, higher feed hardness tolerance, ability to handle feedwater quality fluctuations, optimized power consumption, and quick onsite regeneration of media.
Abstract: This paper reports on the application of fractional electrodeionization (FEDI) in the production of deionized water. The advantages of this two-stage dual-voltage technology over conventional electrodeionization (EDI) are discussed, including better quality of treated water, higher feed hardness tolerance, ability to handle feedwater quality fluctuations, optimized power consumption, and quick on-site regeneration of media. Operating data and experience from two power plants are presented. (orig.)
Patent•
01 Oct 2009
TL;DR: In this article, a water treatment system includes an electrodeionization apparatus 10 and a control means 20 for controlling the voltage applied to the electrodeionisation apparatus 10, wherein the control means20 is constituted of a means which controls the applied voltage in accordance with the treatment capacity of the electrodes and the electric conductivity of the water treated by the electrodes.
Abstract: PROBLEM TO BE SOLVED: To provide a water treatment system which permits the efficient deionization of water to be treated over a long period of time and consequently an extended maintenance cycle. SOLUTION: The water treatment system includes an electrodeionization apparatus 10 and a control means 20 for controlling the voltage applied to the electrodeionization apparatus 10, wherein the control means 20 is constituted of a means which controls the applied voltage in accordance with the treatment capacity of the electrodeionization apparatus. Preferably, the control means 20 is constituted of a means which controls the applied voltage in accordance with the electric conductivity of the water treated by the electrodeionization apparatus or the value of the electric current flowing through the electrodeionization apparatus. COPYRIGHT: (C)2010,JPO&INPIT
Journal Article•
TL;DR: In this article, the ultra pure water production using a self-designed thick cell EDI stack is investigated by using one stage reverse osmosis permeates as feed solutions, and the results show that the operating conditions including applied voltage, dilute flowrate, and concentrate flowrate significantly influence the resistivity of the EDI product.
Abstract: The ultra pure water production using a self-designed thick cell EDI stack is investigated by using one stage reverse osmosis permeates as feed solutions.The results show that the operating conditions including applied voltage,dilute flowrate,concentrate flowrate and feed conductivity significantly influence the resistivity of the EDI product.Under conditions of dilute flowrate of 36 L/h,concentrate flowrate of 3.8 L/h,and applied voltage of 36 V,a product stream with resistivity of 16-18 MΩ·cm is achieved.
Patent•
15 Apr 2009
TL;DR: An electric deionization device suitable for high-purity water manufacturing system which can take the high-pressure processed water drainage which comes from atomic energy facilities and the like as high purity water for regeneration use is presented in this paper.
Abstract: An electric deionization device suitable for high-purity water manufacturing system which can take the high-pressure processed water drainage which comes from atomic energy facilities and the like as high-purity water for regeneration use The electric deionization membrane pile (10) is composed of a plurality of chambers divided respectively by chamber frames (11) and ion-exchange membranes (12) The chambers at the both ends constitute an anode chamber (13) and a cathode chamber (14), while the chambers configured between the anode chamber and the cathode chamber respectively constitute a concentrating room (15) and a deionization chamber (16) A concentrating water export (17) is provided on each chamber frame (11a) constituting the concentrating chamber, and a processing water export (18) provided on each chamber frame (11a) constituting the deionization chamber A concentrating water chamber (24) in which the concentrating water flows away from each concentrating water export of the electric deionization membrane pile, and a processing water chamber (25) in which the processing water flows away form each processing water export are provided in the pressure container divided by the partition (23)
Journal Article•
TL;DR: In this article, the influence of the ratio of resins and the operational parameters on separation performance was investigated, and the results showed that under optimized voltage and resin ratio and with 52.5 mg/L of Ni2+ feed concentration and 3.0 of pH value, the Ni 2+ concentration in dilute product can drop to 0.28 mg/l while that of the concentrated product reaches 3 407 mg/ln, which means the concentration difference can be as many as 12 000 times.
Abstract: The experimental system of electrodeionization with partially circulating of concentrate stream is designed for purifying and concentrating dilute solution containing nickel ion synchronously.The influences of the ratio of resins and the operational parameters on separation performance are investigated.And the results show that under optimized voltage and resin ratio and with 52.5 mg/L of Ni2+ feed concentration and 3.0 of pH value,the Ni2+ concentration in dilute product can drop to 0.28 mg/L while that of the concentrated product reaches 3 407 mg/L,which means the concentration difference can be as many as 12 000 times.The process also has a good stability.
Patent•
28 Jul 2009
TL;DR: A water softener having an ion exchange membrane electrodeionization system is provided to make it not necessary to perform the process of reproducing the ion exchange resin of the water softeners and improve hardness removal ratio of tap water as mentioned in this paper.
Abstract: A water softener having an ion exchange membrane electrodeionization system is provided to make it not necessary to perform the process of reproducing an ion exchange resin of the water softener and improve hardness removal ratio of tap water. A water softener having an ion exchange membrane electrodeionization system comprises: a main body(100) in which tap water flows to discharge tap water after storing tap water in the main body; an anode plate(120) provided within the main body; a cathode plate(122) spaced apart from the anode plate and provided within the main body; a cation exchange membrane(130) disposed between the anode plate and cathode plate to block a movement of anions toward the cathode plate and permit passage of cations; a bipolar membrane(132) disposed on one side of the cation exchange membrane to decompose water into hydrogen ion and hydroxyl ion; and an ion exchange resin(131) disposed between the cation exchange membrane and bipolar membrane.