Analysis of fouling resistance of PAA-g-ZrO₂ composite membrane in filtrating BSA solution

Fouling of PAA-g-ZrO₂ composite membrane by BSA solution was investigated in conjunction with analysis of membrane total resistances and resistances distribution. The total resistances of the PAA-g-ZrO₂ composite membrane and ZrO₂ membrane increased with increasing filtration time, but the growth trend of the PAA-g-ZrO₂ composite membrane total resistances was lower than that of the ZrO₂ membrane. The fouling resistance of the ZrO₂ membrane was R_cp(concentration polarization resistance)-dominant, while R_cp and R_m (membrane resistance) controlled the PAA-g-ZrO₂ composite membrane separation process. The internal plugging resistance (R_if) of the PAA-g-ZrO₂ composite membrane was just half of that of the ZrO₂ membrane. The membrane resistance of PAA-g-ZrO₂ composite membrane increased with increasing pH. The densely packed brush-shaped structure of the PAA chains was considered to be responsible for reducing the protein adsorption on the membrane surface. Furthermore, the PAA-g-ZrO₂ composite membrane displayed high pH-sensitivity for BSA solutions, and could resist protein fouling in high pH applications.