Heterotopic reaction strategy for enhancing selective reduction and synergistic oxidation ability through trapping Cr (VI) into specific reaction site: A stable and self-cleaning ion imprinted CdS/HTNW photocatalytic membrane

Ion imprinted CdS/HTNW photocatalytic membrane (IM-Cd/HT membrane) was prepared by assembling the oxidation type H2TinO2n+1·xH2O nanowires (HTNW) and the reduction type ion imprinted CdS (IM-CdS) for the removal of Cr6+ and tetracycline. Due to the imprinted cavities, Cr6+ was preferentially adsorbed and trapped at specific reaction sites for reduction reactions under the interference of other ions, and the selective reduction coefficients reached 80.01-fold and 91.92-fold. More intriguingly, Cr6+ and tetracycline reacted on the IM-Cd/HT membrane in a heterotopic manner, Cr6+ migrated to IM-CdS for selective reduction, while tetracycline migrated to HTNW for synergistic oxidation, and there was no interference between the two reactions, thereby IM-Cd/HT membrane exhibited a good synergistic balanced removal effect for Cr6+ and tetracycline. Besides, the Cr6+ flux of IM-Cd/HT membrane reached about 2952 L m−2 h−1 bar−1, and the rejection rate of Cr6+ was 62.02%. This study provides a reference for the design of functional self-cleaning membrane with good synergistic photocatalytic ability.