Improved negative charge of tight ceramic ultrafiltration membranes for protein-resistant and easy-cleaning performance

Fouling caused by adsorption is a challenge in protein separation and purification using membrane technology. The interaction between the membrane surface and proteins is significant for developing antifouling modified membranes. In this study, a negative ZrO2 tubular ceramic membrane was constructed by grafting polyacrylic acid (PAA) to mitigate protein fouling. PAA of 2000 Da had little effect on the membrane pore and surface wettability, as characterized by XPS, dextran retention, contact angle, and water permeance. The protein resistance of the modified membrane was investigated by protein filtration. The modified membranes had a higher stable normalized flux (0.6) and flux recovery ratio (90 %) than that of the original membrane. In addition, the performance of the modified membranes was sensitive to the pore sizes of the original membranes. When the original membrane was unable to completely reject bovine serum albumin (BSA), the weak interaction between BSA and the membrane pores would reduce rejection after PAA modification. And the flux recovery ratio of modified membrane increased by 55 %. Overall, PAA modification reduces irreversible fouling by electrostatic repulsion, and improves the protein-resistant and easy-cleaning performance of ceramic membranes.