Activation of Na₂S₂O₈ by MIL-101(Fe)/MoS₂ composite for the degradation of tetracycline with visible light assistance

In this paper, MIL-101(Fe) and MoS₂ composites (MIL-101(Fe)/MoS₂) were synthesized using a facile solvothermal method. As a new degradation system, the synthesized composites were investigated using persulfate (PS) activation based on visible light (Vis). To establish the superiority of a heterogeneous photochemical catalysis system, the MIL-101(Fe)/MoS₂ was used as the catalyst in the presence of Na₂S₂O₈ with visible light irradiation. In the system mentioned, the MIL-101(Fe)/MoS₂ catalyst presented a much better catalytic ability than that of either a single photocatalysis or chemocatalysis system. The better catalytic ability suggests that the MIL-101(Fe)/MoS₂ catalyst was capable of effectively integrating photocatalysis and chemocatalysis leading to the highest degradation efficiency of 85% in 40 min with tetracycline as the target pollutant. The catalytic system MIL-101(Fe)/MoS₂/PS/Vis degraded TC pollutant by forming species of O₂‾, ¹O₂, hydroxyl radicals (•OH) and sulfate radicals (•SO₄‾) to degrade TC. Furthermore, the MIL-101(Fe)/MoS₂ catalyst displayed better catalytic performance compared to those materials that were previously reported, as verified by the good stability (reached 80% after three cycles) and the high TC degradation rate (85%) of the currently developed material. This system may be applicable to the degradation of TC and other challenging organic pollutants.