Fabrication of a New Rationally Designed Mussel-Inspired Cationic Amphiphilic Terpolymer to Enhance the Separation and Anti-Fouling Performance of Membranes

Polyvinylidenefluoride (PVDF) membrane-based systems for treatingoily wastewater are prone to fouling. Herein, we introduced a novelmussel-inspired cationic amphiphilic terpolymer consisting of monomers N,N-diallyldimethylammonium chloride (DADMAC), N,N-diallyltetradecan-1-ammonium chloride (DTDAC), and mussel-inspired N,N-diallyldopamine hydrochloride (DADAHC) to improve theperformance and characteristics of the PVDF membranes for oil-in-wateremulsion separations. The cationic terpolymer, poly(DADMAC-co-DTDAC-co-DADAHC), shortened as PDDD,was synthesized in excellent yields via free radical polymerizationand has good compatibility with the PVDF owing to the presence ofhydrophobic long alkyl chains in DTDAC. The presence of dopamine motifshelps stabilize the PDDD-PVDF membrane by chelating with Fe3+ ions. The water contact angle on the PDDD-incorporated PVDF membraneswas reduced from 87.6 to 54.6 & DEG;, demonstrating improved hydrophilicitythan pristine PVDF (M-0). The incorporation of PDDD into the PVDFimproved the separation efficiencies of the membrane, which reachedup to 99% while treating the oil-in-water emulsions. IncorporatingPDDD into PVDF has significantly enhanced the anti-fouling characteristicsof the membranes, which are indicated by their remarkable flux recoveryratio (FRR) (up to 92%). The hydrophobic and hydrophilic groups workedsynergetically to enhance the performance of the fabricated membrane.

Automated summary

A novel mussel-inspired cationic amphiphilic terpolymer, PDDD, was introduced to improve the performance and characteristics of PVDF membranes for oil-in-water emulsion separations. The incorporation of PDDD into PVDF resulted in improved hydrophilicity and separation efficiencies, with a maximum of 99% for emulsion separation. Furthermore, the modified membranes showed enhanced anti-fouling characteristics, as indicated by a remarkable flux recovery ratio of up to 92%.