Strategy for oxygen vacancy enriched CoMn spinel oxide catalyst activated peroxodisulfate for tetracycline degradation: process, mechanism, and toxicity analysis

Abstract

Antibiotic-like organic pollutants are harmful to aquatic ecosystems and seriously disrupt the ecological balance. Herein, we propose a simple and versatile method to prepare cobalt–manganese oxides with high specific surface area and abundant oxygen vacancies using low-temperature reduction crystallization, which greatly facilitates the adsorption and electron transfer between the catalyst, PDS, and TC, thus accelerating the degradation of tetracycline (TC). Among them, the degradation efficiency of TC in the CoMn₂O₄(C)/PDS system was 99.8% in 60 min and the degradation rate remained above 90% after four cycles. The possible degradation mechanism is also discussed, where Co is the main metal active center of the catalyst and Mn plays an auxiliary catalytic role to promote the generation of reactive radicals in PDS through redox interactions between Co and Mn, where SO₄⁻˙ is the main active species for TC degradation. Finally, the possible degradation pathways of TC are proposed and the toxicity of the intermediates is evaluated. Findings from this work will shed light on the rational design of bimetallic oxide catalysts.