A highly dispersed magnetic polymetallic catalyst to activate peroxymonosulfate for the degradation of organic pollutants in wastewater

Abstract

Oxytetracycline (OTC), a broad-spectrum antibiotic, has posed considerable risks to the ecosystem because of its resistance to adsorption and the inefficiency in biodegradation. In this study, nitrogen–sulfur co-doped graphene oxide anchored with a nickel–zinc ferrite (Zn_0.5Ni_0.5Fe₂O₄-N, S-GO) polymetallic magnetic catalyst was successfully fabricated for the first time by a simple hydrothermal reaction and employed as a peroxymonosulfate (PMS) activator for the rapid and highly efficient degradation of OTC. The obtained catalysts were systemically investigated by numerous characterization analyses to prove the successful synthesis of Zn_0.5Ni_0.5Fe₂O₄-N, S-GO. The total organic carbon (TOC) removal efficiency of the Zn_0.5Ni_0.5Fe₂O₄-N, S-GO/PMS system reached up to 90.7% within 60 min. In contrast, the PMS-only system achieved less than 60% TOC removal efficiency under the same experimental conditions. Moreover, the catalyst not only had high degradation efficiencies for various organic pollutants (tetracycline, sulfadiazine, cephalothin and enrofloxacin) but also exhibited excellent OTC degradation performances in various actual water bodies (distilled water, drinking water, tap water, pond water and river water). This study provides a novel strategy for the development of high-efficiency catalysts, and the proposed Zn_0.5Ni_0.5Fe₂O₄-N, S-GO/PMS system shows great potential in the remediation of practical wastewater.