The synergistic activation of peroxymonosulfate for the degradation of Acid Scarlet GR by palygorskite/MnO2/Fe3O4 nanocomposites

Abstract

A heterogeneous Fenton-like system comprising palygorskite/MnO₂/Fe₃O₄ (PMM) as a superior, low-cost, and eco-friendly ternary catalyst for the activation of peroxymonosulfate (PMS) was investigated with regard to its ability to degrade Acid Scarlet GR in an aqueous solution. Under the optimum catalytic oxidation conditions of 1 g L⁻¹ PMM, 0.7 g L⁻¹ PMS, and an initial pH value of 5, 200 mg L⁻¹ Acid Scarlet GR was completely degraded within 300 min. PMM exhibited outstanding magnetic recovery ability and reusability after nine cycles with a degradation efficiency of up to 95.4%. The PMM catalyst had a broad working pH range. Singlet oxygen ¹O₂ was considered to play the principal role in the degradation of Acid Scarlet GR in the PMM/PMS system. The synergistic effect between MnO₂, Fe₃O₄, and PG substantially accelerated the catalytic activity of PMM, and MnO₂ was identified to be the primary active site. These findings indicate that PMM is a nanocatalyst that can efficiently activate PMS for the treatment of dye-containing wastewater.