Sulfonated ceramic membranes with antifouling performance for the filtration of BSA-containing systems

Membranes are widely used for protein separation and purification in biotechnology and food processing. However, fouling remains challenges in membrane filtration processes and limits further industrial application. In this study, a facile method for constructing the antifouling alumina membrane via sulfonation modification was comprehensively investigated. FTIR, XPS, FESEM, EDS and zeta potential were used to characterize the sulfonated alumina membrane (Al₂O₃-SO₃H membrane) and confirm that organosilanes grafted on the membrane surface and −SH groups were successfully oxidized to −SO₃H. The Al₂O₃-SO₃H membrane showed a strong negative charge in the neutral solution. In the antifouling test, the Al₂O₃-SO₃H membrane exhibited a high permeate flux during the filtration of bovine serum protein (BSA) solution, and its stable permeate flux was approximately-eight times that of the original Al₂O₃ membrane. This was attributed to the sulfonation of Al₂O₃ membrane and enhanced electrostatic repulsion. The Al₂O₃-SO₃H membrane also exhibited good antifouling performance in the filtration of bacteria-containing BSA solution. This was attributed to the electrostatic repulsion of the Al₂O₃-SO₃H membrane against BSA molecules, which reduced the adsorption of BSA on the membrane surface and pore walls. Finally, the structural stability and repeatability of the Al₂O₃-SO₃H membrane were investigated. The sulfonated alumina membranes exhibit excellent antifouling performance and are promising for the separation and purification of BSA-containing systems.