Toward anti-fouling properties and enhanced performance in separation process - carbon nanotubes - PVDF hybrids

Abstract

The development of membranes with anti-fouling properties is one of the leading research paths for emerging membrane technology. In work, anti-fouling PVDF-based membranes were produced. The material engineering focused on the silanization, via molecules equipped either with one or three reactive groups, of the PVDF surface rich in hydroxyl (OH) moieties. Subsequently, carboxylic functionalized multi-walled carbon nanotubes (MWCNTs) were covalently attached to the silanized surfaces. For the first time, the chemically-covalently attached MWCNTs were used to tune the surface features of PVDF for fouling mitigation. All produced materials were characterized and utilized in osmotic membrane distillation for the juice dehydration process of raw apple juice. The tests covered morphology, changes in materials chemistry, wettability, surface charge, thermal stability, and fouling studies in the separation process with natural products. It was revealed that modification mitigates fouling significantly and improves the transport properties of the membranes. The membranes prepared during the modification with a one-reactive group modifier possessed better transport and materials features than hybrid materials grafted with silanes with three reactive groups. It was related to better self-organization of the grafted layers with a one-reactive group molecules.