Abstract:To improve the antifouling performance and enhance the humic acid (HA) removal rate of polyethersulfone (PES) ultrafiltration membrane, the mesoporous silica (MS) was incorporated in PES membrane by phase inversion method and the surface of PES/MS membrane was negatively modified. The effects of MS on the PES membrane structure, surface chemical property and filtration performance were studied. The HA separation property of negatively charged PES/MS membrane and the effects of pH value, ion strength and Ca2+ concentration on the filtration performance were also investigated. SEM images showed that MS particles dispersed evenly on the PES/MS surface and the membrane pore connectivity was improved. After the hydrophilic charged modification, the contact angle of PES membrane decreased from 68° to 57°, the zeta potential decreased from -6.31mV to -11.45mV; the HA removal rate increased from 72% to 95% while the flux decline rate decreased from 29.8% to 4.9%. Results indicated that hydrophilic charged modification on the PES membrane could be an effective way for better removal of HA and reduction of the membrane fouling; In addition, solution environment, including pH, ionic strength and calcium ion concentration, affecting HA filtration process could be adjusted to achieve higher removal rate and less fouling.