Functionalization of zinc oxide (ZnO) nanoparticles and its effects on polysulfone-ZnO membranes

Abstract

Incorporation of nanoparticles in membranes has recently been reported to lead to enhancement of the membrane performance for various applications. In this study, ZnO nanoparticles were synthesized via sol-gel method using zinc acetate and oxalic acid as starting materials. However, the influence of additive, in this case ethylene glycol (EG), on the size of ZnO nanoparticles produced was investigated. All diffraction peaks of XRD patterns indicated the wurtzite structure and the hexagonal phase of ZnO nanoparticles. Uniform spherical particle sizes with lower sizes and reduced agglomeration were observed when EG was used under the same experimental conditions. The particle size was found in the range of 20-30 nm when EG was used as compared to those without EG, which was between 50-60 nm. Dispersion property of the ZnO NPs was further verified by zetasizer analysis. Subsequent incorporation of the smaller size ZnO nanoparticles in membranes has shown improvement in the characteristics and performance of the membranes. Membranes incorporated with ZnO showed improved hydrophilicity and enhancement of membrane performance in terms of permeability, porosity, and rejection ability.