Polyvinylidene fluoride/poly(ethylene-co-vinyl alcohol) blended membranes and a systematic insight into their antifouling properties

PVDF/EVOH (P/E) membranes were prepared via immersion precipitation to realize an antifouling property better than that of PVDF membranes. To determine the optimum conditions for preparing a P/E blended membrane, the effects of the P/E weight ratio and temperature of the coagulation bath on the properties of the blended membrane were investigated. The fouling behaviors and membrane-foulant interaction force of the P/E blended membrane were compared with those of a PVDF membrane for unraveling its antifouling ability. Results show that the P/E membrane appeared to be more hydrophilic, having a higher pure-water flux and bovine serum albumin rejection rate than the PVDF membrane. The integrated performance of the P/E membrane was best when the P/E weight ratio and temperature of the coagulation bath were fixed at 9/1 and 20 degrees C, respectively. Analysis of the antifouling ability revealed that the flux decline rate of the P/E membrane was much less than that of the PVDF membrane. This phenomenon, combined with the measurements of the membrane-foulant interaction force, demonstrates that the membrane-fouling interaction force was reduced by the addition of EVOH, which could weaken the adsorption and accumulation of foulants on the membrane surface or pores and reduce the rate of membrane flux decline.