Rejection of Caffeine and Carbamazepine by Surface-Coated PVDF Hollow-Fiber Membrane System

Abstract

In this research, we investigated surface-coated ultrafiltration (UF) poly(vinylidene fluoride) (PVDF) hollow-fiber membrane for the removal of organic micropollutants (OMPs) in water. Coating of PVDF membranes with poly(1-phenylethene-1,2-diyl)/polystyrene solution through physical adsorption was carried out in two modes: dipping and spraying . The performances of the coated membranes in the rejection of the model organic micropollutants caffeine and carbamazepine spiked in deionized water (at 300 and 500 g/L) correlated with the coating methods used. The dip-coated membranes exhibited a better removal of recalcitrant hydrophobic carbamazepine compared to the spray-coated membrane, whereas for both methods of coating, removal of caffeine was relatively insignificant. From these results, we infer that hydrophobic interactions and size exclusion might be the major removal mechanisms involved in rejection by the coated membranes. The coating layer potentially enhances the reduction of the pore size, decreasing the membrane permeability and providing more sites for possible hydrophobic interactions.