Matrimid® 5218 in fabrication of UF membranes for wastewater treatment: Performance enhancement via graphene oxide nanoplates incorporation

In this paper, Matrimid® 5218 glassy polymer, which is predominantly used for fabrication of the dense gas separation membranes, was applied to fabricate porous ultrafiltration (UF) membranes for liquid phase filtration. The prepared bare and mixed matrix membranes (MMMs), containing different weight percentages of graphene oxide (GO) nanoplates were characterized by SEM, ATR-FTIR, and AFM analyses along with water contact angle (WCA), average pore radius, and porosity measurements. The SEM images displayed an asymmetric structure where the incorporation of hydrophilic GO nanoplates has resulted in construction of more and larger finger-like macrovoids in the sublayer. The optimum membrane, containing 0.02 wt% of GO nanoplates offered the overall porosity of 86.9%, average pore radius of 5.48 nm, as well as the highest pure water flux (PWF) and flux recovery ratio (FRR%) of 266 L m^-2 h^-1 and 83%, respectively. The WCA reduction by 10.7% accompanying with PWF and FFR% values enhancement by 30.6% and 74%, respectively confirmed the favourable effect of GO nanoplates embedment in increasing the prepared MMMs hydrophilicity and antifouling properties. In addition, the optimum membrane represented the highest bovine serum albumin (BSA) protein solution flux of 96.6 L m^-2 h^-1. The fabricated MMMs exhibited the BSA solution rejection values more than 96% and were capable of rejecting two organic azo dyes, including reactive yellow 160 and reactive black 5 more than ∼90%. The results approved that Matrimid® 5218 polymer can be properly employed in fabrication of porous asymmetric UF membranes for wastewater treatment applications.