Facile construction of iron-based MIL-101@MIL-53 Z-scheme heterojunction for the efficient removal of tetracycline hydrochloride

A novel microporous iron-based MIL-101@MIL-53 Z-scheme heterojunction photocatalyst was synthesized via a one-pot solvothermal strategy. Composition, structure, morphology and optical properties of the prepared photocatalyst were characterized using XRD, SEM, FT-IR, XPS and UV-vis DRS. The formation mechanism of the iron-based MIL-101@MIL-53 Z-scheme heterojunction was proposed to be attributed to the gradual transformation from MIL-101 to MIL-53. The in situ formation of an iron-based MIL-101@MIL-53 Z-scheme heterojunction facilitated the electron transfer from MIL-53 to MIL-101. Therefore, the separation of photogenerated charge carriers was enhanced. The removal efficiency of 300 mg L−1 tetracycline hydrochloride reached 99.6% in 90 min under simulated solar light irradiation. Radical capturing experiments showed that ˙O2− was the main active substance for the degradation of tetracycline hydrochloride. This work provided strategies for development and application of iron-based MIL-101@MIL-53 Z-scheme heterojunction and efficient treatment of wastewater with a high tetracycline hydrochloride concentration.