Study on antifouling behaviors of GO modified nanocomposite membranes through QCM-D and surface energetics analysis

Abstract

Organic fouling is one of the most significant challenges that restrict the sustainable application of membranes for large-scale wastewater treatment. The extent of organic fouling depends on membrane-foulant affinity, which relies on the physicochemical properties of the foulant and membrane. In this research, an extended DLVO (XDLVO) interaction energy analysis, fouling experiments, and quartz crystal microbalance with dissipation monitoring (QCM-D) were all employed to investigate the adsorption behavior of organic foulant from steam-assisted gravity drainage (SAGD) produced water on three synthesized ultrafiltration (UF) membranes including pristine polyethersulfone (PES), PES/polyvinylpyrrolidone (PVP), and PES/PVP/ graphene oxide (GO) nanocomposite. In the XDLVO analysis, the fundamental interactions (van der Waals, electrostatic, and acid-base interactions) that control organic fouling were evaluated. Surface tension parameters, derived from contact angle measurements, were employed to calculate the free energy of adhesion between membrane and foulant material to elucidate the differences in flux decline. It was found that acid-base interaction energies between foulant and membrane’s surface were the most influential factor on the total energy of interaction in distance shorter than 5 nm. This investigation demonstrated that surface free energy elements, evaluated for the wastewater and membranes, could successfully anticipate fouling behavior of organic matters on the membrane surface. QCM-D technique was also used to study the fouling behavior of membranes. The QCM-D results contrasted with XDLVO theory and fouling test due to different fluid conditions and surface characteristics.