Graphene oxide composite nanofiltration membrane and its preparation method and application

Abstract

The invention provides a graphene oxide composite nanofiltration membrane and its preparation method and application. The graphene oxide composite nanofiltration membrane is a sandwich structure formed by deposition of an upper layer, a middle layer and a lower layer; the modified graphite oxide of the upper layer and the lower layer The surface of ene is positively charged or non-polar, and the middle layer is graphene oxide; the present invention uses the idea of ​​charge to change the charging properties of graphene oxide, and the potential of the prepared sandwich nanofiltration membrane is "positive / negative / positive", Similar to the principle of same-sex repulsion and opposite-attraction in nature, when nanofiltration membranes process charged solutions, electrostatic interaction will enhance the sieving performance of nanofiltration membranes and enhance their stability; using the principle of polarity Change the polarity of graphene oxide, the cross-linking agent makes graphene oxide carry lipophilic groups, that is, the functional groups are non-polar, and the prepared sandwich structure nanofiltration membrane is "non-polar / polar / non-polar", Therefore, the service life and anti-pollution ability of the membrane in aqueous solution can be effectively enhanced.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and in particular relates to a graphene oxide composite nanofiltration membrane and a preparation method and application thereof. Background technique [0002] In the field of water treatment, the water flux, screening performance and stability of nanofiltration membranes are three key factors to evaluate membrane performance. However, there is always an unbalanced contradiction between water flux and sieving performance, that is, the increase of water flux often leads to the decrease of sieving performance, and the improvement of sieving performance often leads to the decrease of water flux. In addition, under the premise of ensuring that the nanofiltration membrane has good water flux and sieving performance, the stability of the membrane is also crucial. Therefore, it is necessary to fully balance the relationship between the three during the research process, so that The membrane can...

AI Technical Summary

Problems solved by technology

Physical approach shows outstanding performance in limiting swelling of graphene oxide membranes [7,9] , in order to improve the water flux of the membrane under the premise of high screening performance, the graphene oxide membrane is externally treated to limit the swelling of the graphene oxide membrane within a certain range, thus obtaining high water flux and high salt screening rate [7] , but this method needs to be carried out under a relatively high pressure environment, and has a high requirement for the control of the pretightening force

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