In situ synthesis of FeOOH-coated trimanganese tetroxide composites catalyst for enhanced degradation of sulfamethoxazole by peroxymonosulfate activation

Abstract

• FeOOH-coated trimanganese tetroxide composites were obtained by coprecipitation. • 40 MF possesses effective activation performance of PMS for degrading SMX. • 1 O 2 was the dominant active species for SMX degradation. • SMX degradation mechanism in 40 MF/PMS system was proposed. • Ecotoxic evolution of SMX and its degradation products was elucidated. Sulfate radicals based advanced oxidation processes (SR-AOPs) have been widely studied for the removal of pollutants from water, but researchers are still trying to find effective activation methods to improve the productive rate of free radical. Therefore, starting from the Fe-Mn based materials abundant in nature, the construction of in situ FeOOH coated Mn 3 O 4 binary composites through one-step co-precipitation method was successfully achieved, and used it as the active agent of peroxymonosulfate (PMS) to remove sulfamethoxazole (SMX) antibiotics. Expectantly, Composite materials containing 40 wt% FeOOH (40 MF) presented more excellent activation performance of PMS than that of single catalyst, which was mainly attributed to its larger specific surface area, pore diameter, and the effective electron transfer. After 40 min reaction, the degradation efficiency of SMX could reach 92.2% by 40 MF. The main reactive oxygen species (ROSs) detected by chemical capture experiment and electron spin resonance spectroscopy (ESR) were 1 O 2 , SO 4 •- , and • OH in 40 MF/PMS system. Through identification of intermediate products, the degradation pathways of SMX could be defined. The ecotoxicity of degraded SMX was also significantly reduced. Moreover, 40 MF presented a long-term stability by multiple cycles. These results demonstrated that Fe-Mn based materials catalyzed PMS oxidation might be an efficient approach for remediation of wastewater containing antibiotics.