Activation of peroxydisulfate for selective degradation of organic pollutants using magnetic acetylene black in sp2 configuration: Synthesis, performance, and mechanism

Abstract

Carbon materials have garnered increasing attention due to their capacity for activating persulfate in pollutant degradation. Among these materials, acetylene black (AB), which possesses a distinct sp² configuration compared to conventional carbon materials, has been reported as an efficient activator for PDS. However, challenges pertaining to separation and reusability impede its practical application. In this study, we synthesized magnetic acetylene black (MAB) through a facile hydrothermal method. Batch experiments demonstrated that MAB exhibits excellent adsorption performance for the target pollutant and can effectively activate PDS, resulting in over 99 % degradation of BPA when using 1 g/L of MAB and 1 mM PDS. Furthermore, MAB exhibited remarkable efficacy over a broad pH range, superior tolerance towards inorganic anionic species, and easy separation from solution facilitated by an external magnet. The results of radical quenching experiments and electron paramagnetic resonance confirmed the significant role played by an electron transfer pathway in the removal process. Additionally, the OCO groups of MAB (such as carboxyl) acted as reaction sites, facilitating this electron transfer mechanism. Moreover, the MAB + PDS system displayed exceptional selectivity for degrading electron-rich organic compounds, and the quantitative structure–activity relationships (QSAR) analysis revealed a strong linear correlation between removal performance and ionization potentials of these organics, further supporting the predominant contribution of the electron transfer pathway involved. Overall, this work not only presents a successful strategy for applying carbon materials in wastewater treatment but also contributes to understanding the mechanisms underlying persulfate activation using highly graphitized carbon materials.