Enhanced degradation performance of sulfisoxazole using peroxymonosulfate activated by copper-cobalt oxides in aqueous solution: Kinetic study and products identification

5 years ago

Enhanced degradation performance of sulfisoxazole using peroxymonosulfate activated by copper-cobalt oxides in aqueous solution: Kinetic study and products identification

In recent years, numerous studies have been concentrated on enhancing the efficiency of SO4 ⁻ based advanced oxidation processes (AOPs) on eliminating contaminants. In this study, an efficacious heterogeneous copper-cobalt catalyst (Cu0.39Co1.01O4.57) was synthesized by a simple coprecipitation method to activate peroxymonosulfate (PMS) to degrade sulfisoxazole (SIX). On the surface of this catalyst, active sites like Co²⁺, Co³⁺ and Cu²⁺ were found. In the optimal condition, SIX could be completely degraded in 30min at ambient temperature, pH=7 and by 1.87mM PMS and 0.1gL⁻¹ Cu0.39Co1.01O4.57. The addition of this catalyst also enhanced the degradation of other 5 sulfonamides (SAs). The possible catalytic mechanism was discussed that Co²⁺ first formed Co(OH)⁺, then it activated PMS to produce sulfate radicals, and Cu²⁺ on the surface may participate in reducing Co³⁺. Twelve transformation products of SIX by PMS were identified by HPLC–MS/MS analysis. The degradation mechanism of SIX in PMS/Cu0.39Co1.01O4.57 system was proposed, which is comprised of four pathways. Both experiments and theoretical calculations demonstrate that N7, C2 and C6 on the aniline ring, and the SN and ON bonds are the most active sites to be attacked by oxidizing species.

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DOI: S1385894717313025