# pH-Self-Buffering and Flocculation-Enabled Nonradical Oxidation via Magnesium Hydroxide-Activated Peroxymonosulfate for Selective Organic Pollutant Degradation

## TL;DR

A new method using magnesium hydroxide and peroxymonosulfate efficiently degrades pollutants in water while maintaining pH stability and enabling easy separation.

## Contribution

Mg(OH)2 is shown to activate PMS via nonradical oxidation, offering pH self-regulation and flocculation for pollutant removal.

## Key findings

- Mg(OH)2 catalyzes PMS decomposition via singlet oxygen, degrading pollutants like BPA rapidly.
- The system maintains pH stability at ~9.8 and works efficiently across a wide pH range.
- The catalyst is stable over four cycles and resists interference from common anions and humic acid.

## Abstract

Peroxymonosulfate (PMS)-based advanced oxidation is often hindered by pH instability and the lack of post-reaction separation. Herein, commercial magnesium hydroxide (Mg(OH)2) is introduced as a multifunctional catalyst to address these limitations. Mg(OH)2 effectively catalyzed PMS decomposition via a nonradical pathway dominated by singlet oxygen (1O2) generation, achieving rapid and complete degradation of electron-rich pollutants like bisphenol A (BPA) within 40 min. The system exhibits exceptional pH self-regulation, stabilizing the solution at ~9.8 and maintaining high efficiency across an initial pH range of 3–11. Mechanistic studies confirm 1O2 as the primary reactive species with a steady-state concentration of 1.67 × 10−12 M. The catalyst demonstrates strong resistance to common anions and humic acid, along with excellent stability over four cycles. Furthermore, Mg(OH)2 enables in situ flocculation and removal of degradation products. This work highlights Mg(OH)2 as an efficient, stable, and multifunctional activator, offering a integrated strategy for practical wastewater treatment.