Synergistic activation of PDS by a waste-derived catalyst from electrolytic manganese residue and coal gasification fine slag: Performance and non-radical mechanism

In this study, a novel heterogeneous catalyst (E-EMRCG) was successfully fabricated by synergistically integrating electrolytic manganese residue (EMR) and coal gasification fine slag (CGFS) for the efficient activation of peroxydisulfate (PDS). By leveraging the abundant transition metals (e.g., Mn and Fe) inherently present in EMR as active catalytic centers, the incorporation of CGFS significantly enhanced the adsorption capacity and facilitated the structural transformation of these transition metal species, thereby accelerating the PDS activation efficiency. Under optimized conditions (1.0 g L −1 catalyst, 10 mmol L −1 PDS), the E-EMRCG/PDS system achieved a remarkable 97.8% removal of 50 mg L −1 salicylhydroxamic acid (SHA) within 120 min. Mechanistic investigations, including quenching experiments, electron paramagnetic resonance (EPR), and electrochemical measurements, revealed that the degradation was primarily driven by a non-radical pathway involving surface-confined activated persulfate-carbon complexes. Density functional theory (DFT) calculations and chromatographic analysis further identified the O9, O11, N10, and H12 sites as the most vulnerable positions for nucleophilic and electrophilic attacks, leading to the formation of phenolic intermediates. This research provides a sustainable "waste-to-resource" strategy for developing low-cost transition-metal-based catalysts for the advanced remediation of organic-contaminated mineral processing wastewater.