Fouling control in sugarcane juice ultrafiltration with surface modified polysulfone and polyethersulfone membranes

Commercial 50 and 100 kD polyethersulfone (PES) and polysulfone (PS) ultrafiltration membranes were surface modified by UV photografting of poly(ethylene glycol) methacrylate (PEGMA) monomer. The modified membranes were characterized by the degree of grafting, water flux and molecular weight cutoff (MWCO) rating. The flux and fouling of the modified and unmodified membranes were examined with sugarcane juice and its polysaccharide fraction. Under the conditions of this study, the modified membranes displayed a low degree of grafting (26-36 μg/cm²), which was independent of the UV exposure duration; however, both membrane water flux and MWCO rating were affected by the irradiation time. In the best case, the modified membranes exhibited lower fouling with sugarcane juice; furthermore, the propensity to foul also decreased. More significantly, juice flux recovery was almost complete for successive UF-cleaning cycles.