Activation of Na2S2O8 by MIL-101(Fe)/Co3O4 composite for degrading tetracycline with visible light assistance

• MIL-101(Fe) and Co 3 O 4 composites (MIL-101(Fe)/Co 3 O 4 ) were tested as catalysts. • Heterogeneous catalysis system with Na 2 S 2 O 8 and Vis light degrades tetracycline (TC) • Quenching experiments showed that 1 O 2 , •SO 4 ‾, •OH, and O 2 ‾ led to removal of TC. MIL-101(Fe)/Co 3 O 4 composites were synthesized using a facile solvothermal method to establish the superiority of a heterogeneous photochemical catalysis system in the presence of Na 2 S 2 O 8 with visible light irradiation. In the present system, the MIL-101(Fe)/Co 3 O 4 catalyst showed better catalytic performance than the single photocatalytic or chemical catalytic system, implying that the MIL-101(Fe)/Co 3 O 4 catalyst can combine both photocatalysis and chemical catalysis well. When tetracycline (TC) is the target pollutant, the highest degradation efficiency can be achieved within 40 min, reaching to 86 %. Crystallinity, morphology, and elemental valence of the MIL-101(Fe)/Co 3 O 4 composite were explored by using X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as X-ray photoelectron spectroscopy (XPS). From the quenching experiments, it was found that 1 O 2 , SO 4 ‾, OH, and O 2 ‾ make contributions to the effective removal of tetracycline. Apart from that, the recovery and reuse characteristics of MIL-101(Fe)/Co 3 O 4 may facilitate the sustainable wastewater treatment.