Polysulfone/MMT Mixed Matrix Membranes for Hexavalent Chromium Removal from Wastewater

Polysulfone (psf)/nanoclay mixed matrix ultrafiltration membranes with N-methyl pyrrolidone as a solvent and polyvinylpyrrolidone (PVP) as porogen were prepared using phase inversion techniques. Unlike the other nanocomposites membranes prepared using nanoclays, the present work deals with the incorporation of montmorillonite clay (MMT) and MMT modified with methyl dihydroxy ethyl hydrogenated tallow ammonium (mMMT) to psf matrix as nanoparticle to improve the performance of the membrane. The amount of PVP is optimised by analysing porosity and equilibrium water content. The thermal, chemical and morphological characterisation is carried out using X-ray diffractometer, thermal gravimetric analyser, FTIR and scanning electron microscopy. From the studies, it is found that membrane with 0.6% PVP has higher porosity with a lower contact angle. The water flux and chromium (VI) ion rejection were studied using a crossflow filtration unit. The MMT and mMMT concentration was varied from 1 to 5% and found that polymer nanocomposite membrane (psf/mMMT) with 3% mMMT is having higher rejection and flux. Antifouling performance of the pristine membrane, psf/MMT and psf/mMMT membrane was conducted using bovine serum albumin as organic foulant. The flux recovery ratio of psf/mMMT membrane with 3% mMMT increased to 83%, which is higher than the pristine polysulfone membrane, and the total fouling is reduced to 39%.