Controlling the amount of MoSe2 loaded SrTiO3 to activate peroxymonosulfate for efficient elimination of organic pollutants.

Abstract

It is critical to effectively eliminate recalcitrant organic pollutants from wastewater. In this paper, the MoSe₂/SrTiO₃ (MST) catalysts were synthesized through simply controlling the amount of MoSe₂ in the hydrothermal method to activate peroxymonosulfate (PMS) for the degradation of pollutants. The results demonstrated that sulfamethoxazole and tetracycline were almost eliminated by PMS/MST-3 (MoSe₂/SrTiO₃ mass ratio 0.3: 1) activation system. The effect of inorganic anions (Cl ^-, H₂PO₄ ^-, HCO₃ ^-) and metal ions (Cu²⁺, Ni²⁺, Zn²⁺) commonly found in actual water bodies on catalytic reaction was explored. Moreover, SO₄^{• -}, ^•OH and ¹O₂ were identified by EPR tests and scavenger experiments, where the SO₄^{• -} and ^•OH were the dominant reactive species. The XPS analysis indicated that the oxygen vacancies and charge transfer on the catalyst surface were the keys of PMS activation. The effect of active sites in SMX and TC on the catalytic degradation activity was explored by density functional theory, and it was obtained that the central nitrogen site of SMX was more vulnerable in the catalytic system, while the edge oxygen site of TC was more susceptible to attack.