LaFexMn1-xO3 used to activate peroxymonosulfate in the degradation of refractory organics in water: Synthesis, performance, and mechanism

A perovskite catalyst (LaFe 0.05 Mn 0.95 O 3 , LFMO) was synthesized and used to activate peroxymonosulfate (PMS) in the treatment of refractory organic wastewater. The LFMO is a mesoporous material and Fe and Mn dominate the catalytic process. LFMO catalytic oxidative system can remove >96% RhB at 30 min under the optimal wastewater treatment conditions. The degradation process of RhB accords with pseudo-first-order kinetics, and the observed degradation kinetics constant shows an exponential function relationship with five critical parameters. LFMO catalytic oxidative system shows strong pH adjustment ability within the initial pH range of 3 to 9, and the effluent pH stabilizes between 4 and 5. The catalytic performance of LFMO decreases by 11.6% in its 6 th use, a reasonable extension of the treatment time (5 – 10 min) can stabilize the removal rate of RhB at 96%. 1 O 2 , O 2 ∙ − , SO 4 ∙ − and · OH exist in the system, and 1 O 2 plays the dominant role in the degradation of RhB. The working mechanism of LFMO includes three catalytic pathways, which all can produce 1 O 2 . The degradation of RhB undergoes N-de-ethylation, de-amination, de-carboxylation, opening rings, and mineralization. The excellent application feasibility of LFMO catalytic oxidative system has been confirmed by the treatment of three actual antibiotic wastewaters.