Enhanced hydrophilicity of integral membrane

Membrane separation plays a big role in filtering heavy metals in wastewater. In order to achieve good separation, the membrane needs to possess certain properties such as high thermal stability, high water uptake, and high percentage of metal removal. Thus, the fabrication of a blend membrane from chitosan (CS), polysulfone (PSf), and polyvinyl alcohol (PVA) aims to achieve these desirable properties to ensure that a high amount of mercury can be eliminated from wastewater. In this study, a novel blend membrane from PSf, PVA and CS was fabricated by phase inversion method. The integral membranes with different compositions of PVA (1 wt% and 2 wt%) were characterized in terms of thermal stability, water uptake, pure water flux, antifouling properties, and mercury removal. Prior to performance testing, the blending of the integral membranes were confirmed via FTIR analysis. Results show that the integral membranes exhibit higher thermal stability, water uptake and pure water flux compared to pure PSf membrane. PSf/CS/PVA 2 wt% has the highest water uptake and pure water flux which are 233% and 57.96 L/m2h respectively. This enhanced hydrophilicity is attributed to the presence of OH groups in PVA. Meanwhile, PSf/CS/PVA 1 wt% exhibited constant and total mercury removal (100%) during a filtration period of 1 hour. PSf/CS/PVA 2 wt% achieved 70.57% of mercury removal in the first 15 minutes but the percentage decreased to 68.21% at the 30th minute before falling to 0%. In terms of antifouling properties, both membranes undergo irreversible fouling. This may be due to the high concentration of humic acid used during filtration. Hence, further studies are required on the antifouling performance of the membranes.