Enhanced removal of tetracycline by sandwich layer composite membrane based on the synergistic effect of photocatalysis and adsorption.

• A sandwich structured composite membrane with synergistic removal of TC by photocatalysis and adsorption was prepared. • The combination of photocatalysis and membrane filtration significantly reduces membrane fouling. • The maximum stress borne of the membrane were improved by 10.58% using polyester-cotton fabric as the supporting layer. • The removal percentage of TC by the composite membrane can reach 87.10% after four cycles. Environmental pollution has become increasingly serious, especially the abuse of tetracycline (TC) antibiotics, which has brought serious problems to human life. Therefore, the residual TC in the environment has become an urgent problem to be solved. To improve the efficiency of TC wastewater purification and solve the problem of powder material recovery during photocatalysis, a sandwich layer photocatalytic composite membrane with catalytic/adsorption synergistic effect was prepared in this study. The first layer of the composite membrane is composed of a polyether sulfone (PES) membrane loaded with UiO-66-NH 2 /Bi 2.15 WO 6 (UN/BWO) photocatalyst (named as UN/BWO@PES), the middle layer is a support layer composed of polyester/cotton fabric, and the lower layer is composed of a calcium alginate/diatomite (CA@DE) membrane with adsorption for TC. Under dark conditions, the rejection percentage of TC by sandwich composite membrane (M4.5 D 0.02-3) can reach 50.81%, while under light conditions, the removal efficiency of TC by M4.5 D 0.02-3 can reach 93.94%. Even after four cycles, the removal percentage of TC by M4.5 D 0.02-3 can still reach 87.10%. Therefore, the visible light responsive photocatalytic composite membrane developed in this study has dual advantages of photocatalysis and membrane adsorption filtration, and has enormous application potential in wastewater treatment, which can minimize membrane pollution and improve the reusability of photocatalysts. [ABSTRACT FROM AUTHOR]