Tailoring microstructure of polysulfone membranes via novel hexagonal ZnO particles to achieve improved filtration performance

Abstract

Incorporation of nanofillers into polymeric membranes has been the trend in the realm of membrane research owing to the improvements in many filtration characteristics with the modifications of membrane structure, morphology and bulk properties. The major drawback of the nanoparticle embedded membrane is the uncontrollable agglomeration, which could be mitigated by tailoring microstructure of the matrix by using designed nanoparticles. In the present study, polysulfone (PSf) based ultrafiltration membranes incorporated with designed MicNo® platelets composed of strongly bonded ZnO nanoparticles were prepared as single- and double-layer membranes using immersion precipitation technique. Filtration performance, morphological and bulk properties of the novel composite membranes containing MicNo® powders of varying amounts (0.01–1%, wt.) and particle sizes were determined in comparison to those of pristine PSf membrane. Single-layer composite membrane containing 0.5% MicNo® exhibited the greatest permeance improvement of 74% and a marked enhancement of 116% could be achieved with double-layer membrane system containing 0.5% and 0.1% MicNo® in the upper and bottom layers, respectively. The results demonstrated that MicNo® powders were successfully distributed throughout the membrane matrix without any surface imperfections owing to the well alignment of ZnO particles on their hexagonal platelet surfaces, which prevented the agglomeration of primary ZnO particles that ensured a more efficient hydrophilic surface generation in the membrane.