Immobiling enzyme-like ligand in the ultrafiltration membrane to remove the micropollutant for the ultrafast water purification

Abstract Water security is one of the most pressing global challenges due to its effects on human health. To face the challenge of water pollution, membrane technology was widely applied for the removal of pollutants and desalination. In this work, an enzyme-like ligand, Iron (III)-tetraamidomacrocyclic ligand (Fe(III)-TAML), was for the first time immobilized into a polyethersulfone (PES) membrane for the catalytic oxidation removal of micropollutants during the ultrafiltration process. Through the introduction of graphene oxide-polyethyleneimine (GO-PEI), Fe(III)-TAML was successfully immobilized into the membrane. Results shown that porosity and hydrophilicity of the PES membrane were significantly enhanced after GO-PEI modification. Furthermore, about 100% of bisphenol A (BPA) in the feed water was removed after filtration using the Fe(III)-TAML immobilized membrane at a high flux of 192 L/m2 h, which was attributed to the generation of high valence Fe through activating Fe(III)-TAML by H2O2. Moreover, the Fe(III)-TAML in the membrane could be simply regenerated by a re-adsorption process, and the flux and removal efficiency of BPA were stabled during five cycles. Additionally, the TAML/GO-PEI/PES membrane maintained a high water flux and BPA removal efficiency for the filtration of actual surface water. Overall, these results highlight the potential of enzyme-like ligand catalytic oxidation coupled with ultrafiltration to remove micropollutants at a high flux for ensuring the water safety.