Environmental friendly and cost effective caramel for congo red removal, high flux, and fouling resistance of polysulfone membranes

This study demonstrates the caramel as a hydrophilic additive material towards improving the performance and antifouling properties of Polysulfone (PSF) membranes. It is found that the functional molecules that formed upon the caramelization of sugar enhance the performance of the PSF membranes in terms of their permeability as well as the hydrophilicity. Thus, the PSF-based flat sheet membranes were prepared by phase inversion technique with different additional amounts of caramel (i.e., 50 mg, 150 mg and 250 mg). The prepared membranes were characterized and their performance was evaluated by pure water flux, water uptake and contact angle measurements. Studies on the rejection and fouling properties of membranes in water treatment were carried out using Bovine Serum Albumin (BSA). The modified membranes showed a significantly enhanced flux of similar to 350 L/m(2) h and the rejection of BSA was found to be 90%. It was also found that the antifouling capacity of the PSF membranes enhanced with caramel modification. Congo red removal using PSF-Caramel membrane was observed to be very effective in acidic conditions and the dye was able to be successfully recovered using ethanol. The membranes were reused for several times, which showed a consistent performance in flux and rejection of Congo red. Overall, the caramel modified membranes can open up new possibilities in enhancing the thermal, mechanical, hydrophilicity, water flux and antifouling properties of PSF membranes.