Novel chitosan based thin sheet nanofiltration membrane for rejection of heavy metal chromium

Abstract

In recent years, polymeric membranes holds superior position in filtration processes as it was cost effective and simple to prepare. In the present study we have synthesized a novel organic-inorganic hybrid thin sheet membrane using chitosan/polyvinyl alcohol and montmorillonite clay followed by non-solvent induced phase inversion technique. This hybrid clay-polymeric nanofiltration membrane possesses excellent overall performance, such as enhanced hydrophilic nature, and holds good rejection rate. Analytical techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and Scanning Electron Microscopy (SEM) have been employed to characterize the membrane material. Membrane characterizations such as pure water flux, membrane hydraulic resistance, water content, percentage of porosity and pore size were also evaluated. An important characteristic of membrane for long term usage "anti-biofouling activity" is investigated by determining zone of inhibition of membrane on pathogens of bacterial and fungal strains. The remediation of chromium was performed by varying the parameters such as pH, metal ion concentration, applied pressure and thickness of membrane. The rejection of chromium removal by CS/PVA/MMT membrane is confirmed by comparing the spectral images of EDAX and FT-IR taken before and after filtration.

Keywords: Chromium rejection; Fouling; MMT clay; Nanofiltration membrane.