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

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)2effectively 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 confirm1O2as the primary reactive species with a steady-state concentration of 1.67 × 10−12M. The catalyst demonstrates strong resistance to common anions and humic acid, along with excellent stability over four cycles. Furthermore, Mg(OH)2enables in situ flocculation and removal of degradation products. This work highlights Mg(OH)2as an efficient, stable, and multifunctional activator, offering a integrated strategy for practical wastewater treatment.