Permeation and antifouling performance of poly (ether imide) composite ultrafiltration membranes customized with manganese dioxide nanospheres

Abstract

MnO2 nanospheres are prepared by simple hydrothermal technique, and their influence on the permeation, antifouling and contaminant removal properties of poly (ether imide) (PEI) ultrafiltration (UF) membranes is investigated by adding them at three different concentrations such as 0.5, 1.0 and 2.0 wt.% (designated as PEI-0.5, PEI-1 and PEI-2). The hydrophilic property of PEI/MnO2 membranes is investigated using contact angle and pure water flux measurements. The addition of MnO2 nanospheres reduces the contact angle to 60.8° and enhances the pure water flux to 129.8 Lm−2h−1 for PEI-1 membrane due to the increased surface hydrophilicity. SEM and AFM characterization revealed that the custom-made membranes showed noticeable changes in the formation of macrovoid, porosity and roughness parameters. During the separation of contaminants such as bovine serum albumin (BSA), humic acid (HA) and oil, the tailored membranes show enhanced rejection (between 96.8 and 99%) and flux recovery ratio (FRR) (between 95.5 and 99.5%) due to the improvement in hydrophilicity and formation of the water layer on the membrane surface proved their better rejection and antifouling capacity. Hydraulic resistance (14.7 kPa/Lm−2h−1) and tensile strength (5.58 MPa) results suggested that, the PEI-1 membrane showed better resistance to pressure and mechanical stress compared to the standard PEI membrane, due to the changes occurred in their morphologies. However, the additive loading limited at 2 wt.%, in order to avoid the negative effects of MnO2 nanospheres at higher concentrations.