The Regulating Role Of Visible Light On The Activation Of Peroxymonosulfate By MOF-derived 3D Mesoporous Magnetic BiFeO₃

Naproxen（NPX）is a typical anti-inflammatory and anti-rheumatic drug,which is widely used for treating pain and rheumatoid arthritis.Due to its general application and high resistance to biodegradation,NPX has been detected in different water matrix at concentrations ranging from ng L^-1toμg L^-1,such as surface water,groundwater,effluent of wastewater treatment plants even drinking water.It was found NPX had potential harm to human health and traditional water treatment technologies showed poor removal effect to NPX.In this research,sulfate radical-based advanced oxidation process（SR-AOP）is combined with visible-light photocatalysis technology,achieving synergistic and wonderful effect for NPX removal.Research found compared to bismuth ferrite prepared by hydrothermal synthesis method（hs-BFO）and ferric oxide prepared by PB-MOF template-sacrificial method（ts-Fe₂O₃）,bismuth ferrite prepared by PB-MOF template-sacrificial method（ts-BFO）presented highest catalytic activity attributed to its own 3D mesoporous structure and Bi site.In addition,it was found that SR-AOP（ts-BFO/PMS/Dark）and visible light photocatalysis（ts-BFO/Vis）presented synergetic effect to NPX removal in ts-BFO/PMS/Vis system with synergy index of 2.28.Further research found visible light presented a regulating effect to reactive oxygen species（ROSs）formation,that is to say,the greatest contribution to NPX removal in ts-BFO/PMS/Dark system was SO₄^·-,however,h⁺and ¹O₂made greater contribution to NPX removal in ts-BFO/PMS/Vis system.Moreover,the amount of SO₄^·-and·OH in the reaction system reduced,however,the amount of ¹O₂ markedly increased,accompanying the formation of O₂^·-after visible light irradiation.Finally,the formation pathways of ROSs under dark and visible light and the degradation mechanisms of NPX in ts-BFO/PMS/Vis system were proposed.In ts-BFO/PMS/Vis system,NPX removal followed pseudo-first-order kinetic model.The apparent degradation rate constant(k_app)of NPX increased and then decreased with the increase of PMS concentration and ts-BFO concentration;compared to alkaline condition,acidic and neutral conditions were more beneficial to removal NPX;the maximum value of k_appwas obtained when the ratio of ts-BFO concentration and PMS concentration was 1:1.Moreover,response surface experiment results indicated the optimum condition for NPX removal was PMS concentration of 0.12 m M,ts-BFO concentration of 0.12 g L^-1 and initial pH value of 6.6 in ts-BFO/PMS/Vis system.In ts-BFO/PMS/Vis system,the impacts of NPX initial concentration,common anions and natural organic matter of humic acid（HA）on NPX removal were explored,respectively,at optimum condition.Research found the value of k_app decreased with increasing initial concentration of NPX.HPO₄^2-and HCO₃^-ions inhibited NPX removal in order of HPO₄^2->>HCO₃^-,however,NO₃^-ion promoted NPX removal.Humic acid（HA）presented negative impact on NPX removal.