A multi-stage membrane-based ionic liquid concentration and purification system and a method of operating the same

Abstract

The application belongs to the technical field of ionic liquid separation, and provides an ionic liquid concentration and purification system based on a multistage membrane and an operation method thereof, which comprises the following units: a pretreatment unit, a multistage membrane concentration unit, a dehydration unit and a purified water recycling unit. The ionic liquid is introduced into the pretreatment unit for adsorption filtration; the ionic liquid subjected to adsorption filtration is introduced into the multistage membrane concentration unit, sequentially enters a nanofiltration membrane system, a reverse osmosis membrane system, a brackish water reverse osmosis membrane system and a DTRO membrane system for concentration, and primary concentrated ionic liquid and purified liquid are obtained; the primary concentrated ionic liquid is introduced into the dehydration unit, and concentrated ionic liquid is obtained; and the purified liquid is introduced into the purified water recycling unit, and purified water is obtained. The scheme of the application reduces the loss of ionic liquid, avoids denaturation or performance degradation of the ionic liquid, ensures that the purity and use performance of the ionic liquid after concentration and purification meet the industrial recycling requirements, and realizes green and efficient recycling of the ionic liquid.

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