Nanofiltration membrane for treating printing and dyeing wastewater and preparation method thereof

Abstract

The application relates to the field of industrial wastewater treatment, and specifically discloses a nanofiltration membrane for treating printing and dyeing wastewater and a preparation method thereof. The preparation method comprises the following steps: S1. Pour the aqueous solution containing m-phenylenediamine, camphorsulfonic acid and triethylamine onto the surface of polysulfone ultrafiltration membrane, stay for 10-30s, and then remove the excess aqueous solution on the surface; S2. The organic solution of triformyl chloride and interfacial auxiliary polymerization agent is poured onto the surface of the film obtained in step S1, reacted for 5-20s, and then removes the excess solution on the surface; S3. the obtained film in step S2 is left to stand, heat-treated, and washed with water to obtain nano filter membrane. The nanofiltration membrane that the present application makes reaches more than 94% to the rejection rate of NaCl under the filtration pressure of 0.5MPa, MgSO 4 The interception rate reaches more than 99%, and the pure water flux is greater than 25L / m 2 • h for high water flux and high salt rejection.

Description

technical field [0001] The present application relates to the field of industrial wastewater treatment, and more particularly, to a nanofiltration membrane for treating printing and dyeing wastewater and a preparation method thereof. Background technique [0002] Textile printing and dyeing is one of the most internationally competitive traditional industries in China, but it discharges about 1.8 to 2 billion tons of salty wastewater every year, accounting for about 11% of the country's total wastewater discharge. It is one of the key polluting industries in my country. Therefore, in the field of textile printing and dyeing, in order to reduce the discharge of wastewater, reverse osmosis membranes are currently used to treat and reuse printing and dyeing wastewater. However, due to the high desalination rate of the reverse osmosis membrane, in the actual operation process, its operating pressure is high, generally not less than 1.5MPa, the water reuse rate is low, generally ...

AI Technical Summary

Problems solved by technology

However, the current nanofiltration membranes still have the following deficiencies: (1) the rejection rate of monovalent salts (such as NaCl) is not high: the rejection rate of conventional nanofiltration membranes to monovalent salts NaCl is generally below 50%; Low flow rate: especially for some special nanofiltration membranes, that is, nanofiltration membranes with a NaCl rejection rate of 90%. According to literature, patent reports or currently commercialized nanofiltration membranes, the water flux is usually not more than 20L / (m 2 h), unable to meet the demand for industrial reuse water; (3) High filtration pressure: The filtration pressure of existing literature reports and commercialized nanofiltration membranes is generally above 1.0 MPa, and some are even higher than the filtration pressure of low-pressure reverse osmosis, High energy consumption during industrial application; (4) Serious membrane pollution: the higher the filtration pressure, the more significant the compaction effect of the membrane surface fouling layer, the more serious the fouling phenomenon and organic and microbial pollution on the membrane surface, and the recovered water volume increases with time. The more pronounced the drop, the more frequent the chemical cleaning

[0004] Therefore, under the premise of a certain operating pressure, there will be a "trade-off effect" between the water flux and the salt rejection rate during the preparation of the nanofiltration membrane. Faced with the problem of increasing the water flux of the membrane, the desalination rate will always be lost

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