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Method for recycling ion liquid from filature wastewater

A technology of ionic liquid and wastewater, which is applied in textile industry wastewater treatment, general water supply conservation, chemical instruments and methods, etc., can solve the problems of high-quality concentration brine treatment difficulties, high energy consumption of direct distillation, unfavorable energy saving and emission reduction, etc., to achieve The effect of high recovery rate, low cost and low energy consumption

Inactive Publication Date: 2009-12-16
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method consumes a lot of energy, and it is difficult to deal with a large amount of high-quality brine, which brings new problems; Chinese patent CN1804161A discloses a method for recovering ionic liquid in cellulose spinning wastewater, which uses spinning coagulation bath wastewater Through the process of precipitation-filtration-vacuum distillation-atmospheric distillation, the ionic liquid that enters the coagulation bath as a cellulose solvent through wet spinning is effectively recovered
However, due to the low content of ionic liquid in the spinning wastewater, the energy consumption of direct distillation is high, which is not conducive to energy saving and emission reduction

Method used

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  • Method for recycling ion liquid from filature wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The method of the present invention is used to treat the spinning wastewater obtained by preparing wood pulp cellulose fibers with ionic liquid 1-allyl-3-methylimidazolium chloride salt as a solvent, and the mass concentration of the ionic liquid is 0.01%:

[0028] 1. Pretreatment. The spinning waste water containing wood pulp cellulose fiber is subjected to the pretreatment process of sedimentation, rough filtration and fine filtration in order to filter out the mechanical impurities in it to obtain the pretreatment liquid.

[0029] 2. Ultrafiltration process treatment. Using an ultrafiltration membrane with a molecular weight cut-off of 6000, the pretreatment liquid obtained in the first step of ultrafiltration separation treatment at 0.01MPa is obtained to obtain an aqueous ionic liquid solution with a mass concentration of no wood pulp cellulose and still about 0.01%; the separated The wood pulp cellulose aqueous solution is directly returned to the pretreatment li...

Embodiment 2

[0033] Using the method of the present invention to treat the spinning waste water obtained by preparing polyacrylonitrile fibers with ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate as a solvent, the mass concentration of the ionic liquid is 0.5%:

[0034] 1. With embodiment 1;

[0035] 2. Ultrafiltration process treatment. Using an ultrafiltration membrane with a molecular weight cut-off of 10,000, the pretreatment solution obtained in the first step of ultrafiltration separation treatment at 0.1MPa is obtained to obtain an aqueous ionic liquid solution that does not contain polyacrylonitrile and still has a mass concentration of about 0.5%; the separated The polyacrylonitrile aqueous solution is directly returned to the pretreatment liquid.

[0036] 3. Nanofiltration concentration treatment. The ionic liquid aqueous solution obtained in the second step is used as the raw water concentrated by nanofiltration to carry out nanofiltration concentration treatment, t...

Embodiment 3

[0039] The method of the present invention is used to treat the spinning wastewater obtained by preparing polycotton fibers with ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium chloride salt as a solvent, and the mass concentration of the ionic liquid is 5%:

[0040] 1. Same as embodiment 1.

[0041] 2. Ultrafiltration process treatment. Adopting the ultrafiltration membrane that the molecular weight cut off is 50000 under 0.5MPa ultrafiltration separates and processes the pretreatment liquid obtained in the first step, obtains the ionic liquid aqueous solution that does not contain the mass concentration of polycotton fiber and is still about 5%; The cellulose aqueous solution is directly returned to the pretreatment liquid.

[0042] 3. Reverse osmosis concentration treatment. The ionic liquid aqueous solution obtained in the second step is used as the concentrated raw water of reverse osmosis to carry out reverse osmosis treatment, the desalination rate (1000ppm NaCl) ...

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Abstract

The invention relates to a method for recycling the ionic liquid in spinning wastewater, which comprises the processes: first, the spinning wastewater is pretreated by precipitating, roughly filtering as well as finely filtering to obtain the pretreatment solution; then, the pretreatment solution is processed by ultrafiltration process to obtain the water solution of the ionic liquid with mass concentration of 0.01-5 percent and the separated cellulose and the cellulose in polyacrylonitrile or the polyacrylonitrile are further processed by ultrafiltration washing and concentration or drying and then the obtained solution is recycled; ultrafiltration membrane of molecular weight cutoff adopted by the ultrafiltration process is 6000-50000 and the operation pressure is 0.01-0.5MPa; the obtained ultrafiltration water solution is further processed by nanofiltration and the reverse osmosis to obtain concentration solution of the ionic liquid with mass concentration of 5-30 percent and removed water after concentration is recycled and reused; the desalinization ratio of the nanofiltration membrane is 50-98 percent and the operation pressure is 0.4-1.0MPa; the desalinization ratio of the reverse osmosis membrane is 98 percent and the operation pressure is 1.0-15MPa; at last, the concentration solution of the ionic solution is decompressed and distilled under 60-110 DEG C to obtain the ionic solution with purity of 95-99 percent.

Description

technical field [0001] The invention relates to a separation membrane application technology, specifically a method for recovering ionic liquids in aqueous solutions by using separation membranes, especially a method for recovering ionic liquids from cellulose or polyacrylonitrile spinning wastewater, International Patent Classification The number is proposed to be Int.Cl.D01F 13 / 02 (2006.01). Background technique [0002] Ionic liquids are usually composed of alkylpyridine or dialkylimidazolium quaternary ammonium cations and tetrafluoroborate, hexafluorophosphate, nitrate, halogen and other anions, which have strong polarity, non-volatility, non-oxidation, good solubility and Most of the reagents are stable and have excellent characteristics. Room temperature ionic liquid, as a new type of green solvent, has been widely studied and applied in spinning cellulose fiber engineering, which has good social benefits. However, due to the high price of ionic liquids, industrial ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C02F1/52C02F1/44C02F1/04B01D61/14C02F103/30
CPCY02A20/124Y02A20/131
Inventor 王薇程博闻杜启云肖长发宋俊
Owner TIANJIN POLYTECHNIC UNIV