Inositol hexaphosphate assisted polyamide thin-film composite membrane with ultrahigh performance for water desalination and dye fraction

Abstract

Developing membranes with highly permeable and selective separation remains a challenge. Here, inositol hexaphosphate (IP6) was first introduced into the active layer for preparing an IP6 integrated polyamide (IP6PA) thin-film composite (TFC) membrane. The IP6PA TFC membrane possessed a thinner PA layer with a smoother and better hydrophilic surface as well as strengthened electronegativity and enlarged pore size. The IP6PA membrane that was prepared with a low IP6 content presented a high pure water flux of 20.5 LMH/bar (1.6 times higher than that of the control membrane), and a high Na2SO4 rejection rate (98.5 %), which could be used to completely remove typical dyes and natural organic matters. Notably, the IP6PA membrane fabricated with a high weight ratio of IP6 exhibited an ultrahigh water flux (111.7 LMH/bar) while maintaining superior rejections for Congo red (98.5 %), Direct red 23 (98.6 %), and Brilliant blue R250 (99.5 %). The results show that the modified membrane presented excellent performance in separation of organic/salts, particularly with its outstanding permeability and superior rejection rate, compared with those of most reported polymeric membranes. This work provides a new scheme for the rational design and manufacture of natural acid regulated polyamide composite membranes with enhanced performance for water treatment.