Electrodeionization method and electrodeionization apparatus for treating low concentration ionic solution

Abstract

The invention discloses an electrodeionization method and an electrodeionization apparatus for treating a low concentration ionic solution, and relates to the technology of desalination and ultrapure water treatment. Adhering a material capable of catalyzing water dissociation (5) to one side facing to a light chamber of a cation exchange membrane (3) of the electrodeionization apparatus. A conversion degree of a resin in the light chamber can be easily controlled by changing the adhering positions of the catalytic layer (5) of the cation exchange membrane (3), changing types of the catalytic materials and changing resin filling ratios of a bed layer of the light chamber, and then a removal degree of salt ions can be controlled. With the abovementioned way, relatively high resin regeneration degree can be realized in a relatively low applied voltage, so that a relatively high ion removal rate can be realized at a relatively low operating voltage. The electrodeionization apparatus can significantly reduce the applied voltage and energy consumption, thus reducing an operating cost, so the electrodeionization apparatus has important application value in the field of heavy metal ion removement and ultrapure water production.

Description

technical field [0001] The invention relates to an electrodeionization method and device for treating low-concentration ion solutions, which are used to improve the performance of the electrodeionization system, and more specifically relate to a water dissociation catalyst attached to the cation exchange membrane in the deionization chamber , to increase the degree of ion exchange resin regeneration in the desalination chamber bed, to reduce the voltage and energy consumption of the membrane stack, and to obtain a higher ion removal rate with lower energy consumption. Background technique [0002] In the field of ultrapure water preparation, electrodeionization (EDI) technology is gradually replacing the traditional ion exchange method and becoming the mainstream technology. EDI is a new composite separation process that fills the fresh water chamber of the electrodialyzer with ion exchange resin, combines ion exchange and electrodialysis, and realizes deep removal of low-co...

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Problems solved by technology

But there are the following problems: (1) The external resistance element undoubtedly increases the total resistance of the membrane stack in a disguised form. Under the same ion removal rate, the voltage of the membrane stack increases and the energy consumption increases; (2) The resistance added at the outlet In fact, the function of resistance is realized by hindering the transfer path of ions, so while realizing the current offset, the resistance of ion transfer is increased, and the salt ions in the solution need to bypass the resistance element during transfer to pass out of the dilute chamber

However, this method also has the problem of increasing the total resistance. At the same time, there is no ion mass transfer channel in the doped particles, which hinders the mass transfer of ions. These two aspects also bring about the problem of increased energy consumption.

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