Activated clay/Opuntia microdasys incorporated polyvinyl alcohol membranes for fouling mitigation in wastewater filtration

Abstract

Membrane technology in water treatment is developing quickly, but more selectivity, specificity and fouling control are needed to efficiently target contaminants and recover useful pollutants with the least amount of energy. In this study, a solution casting process was utilized to successfully fabricate a series of ultrafiltration polyvinyl alcohol (PVA)-based membranes using varying amounts of activated clay (AC) and Opuntia microdasys (OM) as fillers. The morphology and chemical composition of the membranes were verified by SEM-EDS, FTIR, 1HNMR, XRD, and ZETA-sizer investigations. The incorporation of OM in addition to AC had a substantial impact on the morphology, hydrophilicity, porosity, filtration efficiency and antifouling characteristics of the produced membranes. Dead-end filtration studies were carried out on the membranes. The pure PVA membrane (MPVA) showed moderate porosity (52.1%) and pure water flux (PWF) (55.4 L/m²/h). In contrast, with the addition of AC and OM (1:1) to the MPVA the composite membrane exhibited significantly enhanced porosity (68.0%) and PWF (67.5 L/m²/h). The MPVA/AC:OM resulted in a 15.9% increase in porosity and a 21.8% increase in PWF, demonstrating substantial improvement in membrane performance. The results show that the composite membrane (MPVA/AC:OM)significantly outperforms the MPVA membrane, with a 29.7% increase in removal efficiency (RE) from 54.6% to 84.3% and a 41.4% reduction in fouling from 29.6% to 17.3%. Moreover, the flux recovery ratio (FRR) increases from 70.4% for the MPVA to 87.1% for the MPVA/AC:OMmembrane, indicating superior antifouling properties. The presence of a porose hydrophilic layer, which is created by AC and OM on the membrane surface inhibits the accumulation of contaminants, leading to a high FRR value.