Improved degradation of tetracycline by Cu-doped MIL-101(Fe) in a coupled photocatalytic and persulfate oxidation system: Efficiency, mechanism, and degradation pathway

•MIL-101(Fe/Cu) exhibited superior activity for SR-AOPs coupled with photocatalysis on TC degradation.•Compared with MIL-101(Fe), MIL-101(Fe/Cu) showed higher binding energy for PS (-5.92 eV).•Doped Cu could capture the photogenerated electrons to inhibit recombination of electrons-holes pair.•DFT calculation indicated that MIL-101(Fe/Cu) has greater electronic conductivity.