Chitosan based ceramic ultrafiltration membrane: Preparation, characterization and application to remove Hg(II) and As(III) using polymer enhanced ultrafiltration

Abstract

This work presents the fabrication of chitosan based ceramic membranes using dip coating technique. Low-cost ceramic supports were prepared from local clay of IIT Guwahati and kaolin with an average pore size of 1093 nm and porosity of 0.37. Different ceramic membranes were prepared by varying chitosan concentration and dipping time and were characterized using scanning electron microscope (SEM), air and hydraulic permeability tests. The average pore sizes were in the range of 760–13 nm which confirmed that the chitosan impregnated ceramic membranes were applicable for both microfiltration (MF) and ultrafiltration (UF) applications. An increase in both chitosan concentration and dipping time was found to reduce the pore size. The lowest pore size ultrafiltration membrane (pore size: 13 nm) was used for the removal of mercury and arsenic from wastewater by polymer enhanced ultrafiltration (PEUF) technique using polyvinyl alcohol (PVA) as the chelating agent. The effects of initial concentrations of mercury, arsenic and PVA on the extent of removal of both the heavy metals were investigated in detail. The efficiency of PEUF was explored in terms of rejection of metals and permeates flux. Almost 100% removals were observed for both 500 μg L −1 mercury and 1000 μg L −1 arsenic.