Electrodeionization (EDI) method and system dispensing with ion exchange membranes

Abstract

The invention discloses an electrodeionization (EDI) method and system dispensing with ion exchange membranes. The system is characterized in that porous water distribution plates, top electrodes, ion exchange resins, bottom electrodes and porous floating blocks with density less than that of water are placed in an insulating cavity from top to bottom in sequence; a top cover and the upper ends of cylindrical shells are sealed by upper seal rings; a bottom cover and the lower ends of the cylindrical shells are sealed by lower seal rings; the porous water distribution plates and the top electrodes are fixed between the top cover and the end faces of the cylindrical shells; the bottom electrodes are fixed on the porous floating blocks; intermediate seal rings are installed between the porous floating blocks and the cylindrical shells; and the top and bottom electrodes are respectively connected with a high-voltage direct current power supply. The method and the system have the following beneficial effect: the problems of membrane pollution, concentration polarization, scaling, hydroxide precipitates formed on the membrane surfaces when the heavy metal wastewater containing Cu<2+>, Ni<2+> and other ions are treated because the ion exchange membranes are adopted for EDI are solved. The method and the system are suitable for preparation of highly pure water, purification of electroplating rinse wastewater containing heavy metal ions and treatment of water and wastewater aiming at removing the ionic impurities.

Description

technical field [0001] The invention relates to an electrodeionization method and system, in particular to an electrodeionization method and system without an ion exchange membrane. Background technique [0002] Electrodeionization (EDI) is an environmentally friendly deionization method that only consumes electricity without consuming chemicals. Compared with ion exchange, reverse osmosis, nanofiltration, electrodialysis, distillation, capacitive deionization (CDI) and other methods, EDI has outstanding advantages such as high processing efficiency, environmental friendliness, and easy operation. It has a good industrial application prospect in the treatment of heavy metal wastewater. Today, EDI has been used in the preparation of high-purity water in industries such as medicine, electric power, semiconductor, chemical agent production, food and beverage. The quality of the effluent can reach the level of the traditional "mixed bed", or even better, which is beyond the re...

AI Technical Summary

Problems solved by technology

First of all, conventional EDI is actually equivalent to a kind of electrodialysis filled with ion exchangers in the fresh water chamber, which requires the use of a large number of ion exchange membranes.

Furthermore, some problems related to ion exchange membranes often occur during the operation of conventional EDI, such as: membrane fouling, concentration polarization, fouling, and the treatment of 2+ 、Ni 2+ Hydroxide precipitation is formed on the membrane surface during plasma heavy metal wastewater

The above defects have seriously affected the popularization and application of EDI

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