# Synergistic Activation of Peroxymonosulfate by CoMnOx Supported on Coal Gangue for Alkaline Wastewater Treatment

## TL;DR

A new catalyst made from coal gangue efficiently degrades phenol in alkaline wastewater using peroxymonosulfate.

## Contribution

A CoMnOx@CG catalyst is introduced for efficient and stable PMS activation in alkaline wastewater treatment.

## Key findings

- CoMnOx@CG achieved over 90% phenol removal within 10 minutes at pH 9 and 11.
- The catalyst maintained over 85% efficiency after four cycles with minimal cobalt leaching.
- Singlet oxygen, sulfate radicals, and hydroxyl radicals were identified as key reactive species in phenol degradation.

## Abstract

This study explores the application of a cobalt–manganese oxide catalyst supported on coal gangue (CoMnOx@CG) for peroxymonosulfate (PMS) activation to degrade phenol in coal chemical wastewater (CCW). The synthesized CoMnOx@CG catalyst demonstrated remarkable catalytic activity, achieving above 90% phenol removal within 10 min at pH 9 and 11. More importantly, the catalyst exhibited excellent stability and reusability, maintaining over 85% phenol removal efficiency after four consecutive cycles and cobalt leaching below 100 μg/L. Quenching experiments and electron paramagnetic resonance (EPR) analyses revealed that singlet oxygen (1O2), sulfate radicals (SO4·−), and hydroxyl radicals (·OH) contributed to the degradation process. When treating actual CCW, the system significantly reduced both phenol and fluorescent dissolved organic matter, demonstrating its effectiveness for complex wastewater matrices. CoMnOx@CG provides a sustainable and practical solution for alkaline refractory wastewater remediation.