Thin film composite membranes: Preparation, characterization, and application towards copper ion removal

Abstract

A novel thin film composite (TFC) membrane was fabricated from a thin layer of hybrid membrane formulated from a blend of polyvinyl alcohol (PVA)/chitosan and cross linked with tetraethylorthosilicate (TEOS), which was layered on the polysulfone (PSF) membrane. Besides producing membrane from polymer blend of PVA/chitosan only, concentrations of TEOS as cross linker was varied at 1 wt%, 3 wt% and 5 wt% with fixed concentration of PVA solution (10 wt.%) and chitosan (2 wt.%) respectively during the formulation of hybrid membranes. The thermal properties, mechanical strength, water contact angle, swelling measurement and anti-fouling behaviour of these membranes were investigated. The performance of the thin film composite was evaluated through filtration of the pure copper ion solution and the industrial wastewater containing copper respectively. The fabricated TFC with 3 wt.% TEOS was found to possess better tensile strength and strain, and thermal stability as compared with other concentration of TEOS. The membrane also exhibit good rejection of copper ion (> 90%) from pure copper solution especially at pH 7 of feed solution. A further treatment conducted on the wastewater reveals that TFC with 3 wt.% TEOS could remove the copper ion, where the filtered water could be directly discharged to the river. Furthermore, the TFC portrayed good anti fouling behaviour, where it have 3% of relative flux decay and 76% of relative flux recovery even with the presence of humic acid as NOM (natural organic matter).