Efficient aniline aerofloat degradation by oxygen vacancies-rich copper tailings/peroxymonosulfate system: Performance evaluation and active sites

Abstract

Using peroxymonosulfate (PMS) activation system employing inexpensive solid waste-based catalysts to degrade organic pollutants is a sustainable strategy. In this study, a catalyst derived from copper tailings (CT-BA5) was developed to efficiently activate PMS for aniline aerofloat (AAF) degradation. The micromorphology of copper tailings (CT) was transformed from blocky to porous and loose after the modification, exposing more active sites for PMS activation. The degradation rate constant (k_obs) of AAF increased to 23.4 times of CT. The degradation efficiency of AAF by CT-BA5/PMS system was 98.79 % within 10 min. The results of XPS, ESR and DFT calculations demonstrated the important roles of Ca₃Fe₂Si₃O₁₂ and Ov as active sites in the reaction process, which enhanced the electron transfer rate and Fe(II)/Fe(III) valence cycle of the catalyst, thus promoting the generation of reactive oxygen species (ROS). ¹O₂ was the dominant ROS responsible for AAF degradation and preferentially attacked the P-N bond of AAF. Furthermore, the results of cycling experiments and actual flotation wastewater treatment showed CT-BA5 had excellent reusability and practical applicability. In conclusion, this study provides a solution for the development of solid waste-based environmental remediation materials and waste-to-energy treatment, which is expected to be widely used in practical wastewater treatment.