Construction of photocatalytic-persulfate synergistic system for efficient removal of environmental pollutants

Abstract

The persulfate-based advanced oxidation processes (PS-AOPs) can potentially enable the cost-effective and efficient removal of environmental pollutants. However, to advance this technology, an efficient photocatalytic composite persulfate system that removes recalcitrant organic pollutants from water is required and the regulatory mechanisms of free radical reactions during the removal process must be thoroughly understood. In this study, Co₃O₄ derived from metal–organic frameworks (MOFs) are loaded onto potassium ion (K⁺)-etched graphite-phase carbon nitride, forming an efficient PS-AOPs system that removes approximately 99 % of sulfamethoxazole (SMX) within 30 min. The incorporated K⁺ ions and efficient charge-transfer channels synergistically extend the lifetime of the photo-generated charge carriers, effectively enhancing the activation of peroxymonosulfate (PMS) and consequently improving the photocatalytic removal efficiency of SMX. Besides establishing a viable pathway for the removal of recalcitrant pollutants in water, this study deepens our understanding of the mechanism underlying PMS activation by metal–carbon-based catalysts.