Novel polyethersulfone (PES)/hydrous manganese dioxide (HMO) mixed matrix membranes with improved anti-fouling properties for oily wastewater treatment process

Abstract

In this work, hydrophilic hydrous manganese dioxide (HMO) nanoparticles were synthesized and used as the inorganic filler for the preparation of mixed matrix membranes (MMMs). The aim of adding HMO nanoparticles into the polyethersulfone (PES) membrane matrix is to improve membrane hydrophilicity and anti-fouling resistance against oil deposition and/or adsorption. The resulting membranes were characterized by SEM, AFM, FTIR, contact angle measurements and ultrafiltration (UF) of synthetic oily wastewater. Experimental results showed that the hydrophilicity of the PES/HMO membrane was significantly improved to a low value of contact angle (16.4°) by HMO loading, which as a consequence led to a promising pure water permeability (573.2 L m⁻² h⁻¹ bar⁻¹). In comparison, the pristine PES membrane only demonstrated 69.5° and 39 L m⁻² h⁻¹ bar⁻¹, respectively. Furthermore, the PES/HMO membrane exhibited an excellent oil rejection (almost 100%) and a promising water flux recovery (75.4%) when it was used to treat a synthetic oily solution containing 1000 ppm oil. The promising anti-fouling properties of the PES/HMO membrane could be attributed to the presence of hydrophilic –OH groups on the membrane surface resulting from HMO addition, making this membrane less susceptible to fouling when challenged with oil-in-water emulsions.