1-(3-Aminopropyl) imidazole (APIm) modified ultrafiltration (UF) membrane for mitigating alginate fouling caused by calcium

UF is widely used as a wastewater treatment and recycling technology. However, membrane fouling is still an important factor affecting the wide application. In this study, APIm with positive amino group was adsorbed to the surface of the carboxylated polyacrylonitrile (PAN) membrane by electrostatic force to reduce the fouling of sodium alginate (SA) caused by Ca 2+ . The results show that 1 v/v% APIm was selected as the optimal dosage, accompanied by the highest water flux of 330.5 L·m -2 h −1 bar −1 and bovine serum albumin (BSA) rejection rate of 91.0 %. When the concentration of Ca 2+ was increased to 10 mM, the Ca 2+ catch amount increased to 48.25 mg/cm 2 . The main anti-fouling mechanism was that APIm captured a certain amount of Ca 2+ in situ, destroyed the complex structure of sodium alginate (SA) and Ca 2+ . Then the fouling layer was easy to be removed by physical cleaning. At the concentration of 10 mM Ca 2+ , the membrane flux recovery rate of 1 v/v% APIm membrane was increased to 80.1 %. This study demonstrates a fouling control strategy for in-situ removal of Ca 2+ bound SA fouling, providing a new approach for the future development of UF membrane.