Aminated polysulfone/TiO2 composite membranes for an effective removal of Cr(VI)

A hydrophobic, ultrafiltration (UF), polysulfone (PSI) was reformed into a hydrophilic polymer by introducing amine groups via chemical modification. The amination was achieved by nitration to PSf followed by reduction using Na2S2O4. The modified polymer (aPSf) was characterized by NMR spectroscopy, ATR-IR, DSC and TGA. aPSf was further made into a composite membrane by using nano fillers. The prepared membranes were characterized by XRD, SEM and ion exchange capacity (IEC). The transformation in phase of TiO2 from anatase to rutile due to excess internal strain caused by amine groups was revealed by XRD patterns. Water uptake (WU), contact angle (CA) and pure water flux (PWF) were analyzed to study the hydrophilicity and performance of the membranes. These membranes were further considered for a novel approach of chromium removal by rejection/separation process. Essentially 100% separation was achieved depending on the surface charge properties of membrane, dosage of nano fillers, pH and interference of counter ions on rejection process. (C) 2015 Published by Elsevier B.V.