Effects of different Ca2+ behavior patterns in the electric field on membrane fouling formation and removal of trace organic compounds
Ruying Li , Zhen Du , Min Ji
DOI:10.1016/j.jes.2021.03.046
Received February 08, 2021,Revised , Accepted March 31, 2021, Available online April 21, 2021
Volume 34,2022,Pages 292-300
The effects of Ca2+ on membrane fouling and trace organic compounds (TrOCs) removal in an electric field-assisted microfiltration system were investigated in the presence of Na+ alone for comparison. In the electric field, negatively charged bovine serum albumin (BSA) migrated towards the anode far away from the membrane surface, resulting in a 42.9% transmembrane pressure (TMP) reduction in the presence of Na+ at 1.5 V. In contrast, because of the stronger charge shielding of Ca2+, the electrophoretic migration of BSA was limited and led to a neglectable effect of the electric field (1.5 V) on membrane fouling. However, under 3 V applied voltage, the synergistic effects of electrochemical oxidation and bridging interaction between Ca2+ and BSA promoted the formation of denser settleable flocs and a thinner porous cake layer, which alleviated membrane fouling with a 64.5% decrease in TMP and nearly 100% BSA removal. The TrOCs elimination increased with voltage and reached 29.4%–80.4% at 3 V. The electric field could prolong the contact between TrOCs and strong oxidants generated on the anode, which enhanced the TrOCs removal. However, a stronger charge shielding ability of Ca2+ weakened the electric field force and thus lowered the TrOCs removal.
