Polyamide composite nanofiltration membrane and preparation method thereof

Abstract

The invention provides a polyamide composite nanofiltration membrane and a preparation method thereof.The polyamide composite nanofiltration membrane comprises a supporting base layer and a polyamidefunctional layer obtained on the supporting base layer through interfacial polymerization, and the polyamide functional layer comprises raw materials including diamine, inorganic salt, organic acid, polybasic acyl chloride, an oil-phase solvent and deionized water; wherein the diamine comprises at least one of piperazine, hexamethylenediamine, diaminopyridine and diaminopyrimidine; and the inorganic salt comprises at least one of lithium chloride, calcium chloride, sodium chloride, magnesium sulfate, lithium bromide and calcium bromide. The preparation method comprises the following steps: step 1, preparing a water-phase solution; step 2, preparing an oil-phase solution; and step 3, preparing the polyamide composite nanofiltration membrane. The water flux of the polyamide composite nanofiltration membrane prepared by the method is as high as 73.7 LMH, the rejection rate of divalent salt is as high as 99.31%, and the rejection rate of monovalent salt is as low as 31.83%. The preparationmethod is simple, short in technological process and low in cost.

Description

technical field [0001] The invention relates to the technical field of nanofiltration membrane preparation, in particular to a polyamide composite nanofiltration membrane and a preparation method thereof. Background technique [0002] With the rapid development of the global economy, the shortage of water resources worldwide has become increasingly apparent. The amount of wastewater treatment is also increasing, coupled with the country's mandatory requirement for zero discharge of wastewater, the recycling of wastewater has attracted widespread attention in the industry. Because nanofiltration membranes can separate salt very well, people pay more and more attention to them, and the market share of nanofiltration membranes is growing rapidly. [0003] Nanofiltration membrane-related research began in the 1970s. Film-tec Company North Star Research Institute, J.E.Cadotte et al. used piperazine (PIP) as the aqueous phase reaction monomer and organic phase monomer trimesoyl c...

AI Technical Summary

Problems solved by technology

[0004] But, there is following deficiency in existing nanofiltration membrane: (1) water flux is low; (2) rejection rate is not too high, and the rejection rate to divalent salt (as magnesium sulfate) is between 92%-97%

[0005] In summary, there is an urgent need for a polyamide composite nanofiltration membrane and its preparation method to solve the problems of low water flux and low rejection in the prior art

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