Effect of three different PEO-containing additives on the fouling behavior of PES-based ultrafiltration membranes

PES-based hollow fiber membranes were fabricated using three different PEO-containing additives (PEG-10 k, Pluronic (R) F127 and Triton (R) X100) in the starting polymer dope. All additives enhanced pure water permeance significantly, which was attributed to the increased porosity and pore connectivity caused by the hydrophilicity of the additives. ATR-FTIR analyses of the membrane surfaces after fabrication and after storage in water revealed that all three additives remain in the membrane matrix after fabrication and do not leach out after 60 days. The fouling behavior of the three membranes containing additives and the pure PES membrane was investigated in constant permeate flux filtrations. All three additives decreased the degree of fouling while the membrane with PEG experienced more adsorptive fouling in the first cycle compared to the other two membranes with additives. The fouling reversibility was also better with the two amphiphilic additives Triton and Pluronic. The better fouling behavior with these additives is explained with their amphiphilic nature, which probably results in PEO brushes on the membrane surfaces regardless of the molecular weight of the additive