Glucose-montmorillonite hydrochar composite activating peroxymonosulfate for sulfentrazone rapid degradation and phytotoxicity alleviation to rice

Sulfentrazone is an excellent herbicide for the control of broad-leaved weeds and some grasses. However, its herbicidal residues pose potential risks to the environment. The use of carbonaceous materials as catalysts for activating peroxymonosulfate (PMS) for managing pesticide contamination has attracted considerable attention. Herein, the rapid degradation of sulfentrazone in water and the alleviation of sulfentrazone-induced phytotoxicity alleviation to rice were investigated using glucose-montmorillonite hydrochar (GM-HC) activating PMS. The findings revealed that the GM-HC/PMS system can rapidly degrade sulfamethoxazole and achieved 93.90% of removal efficiency in 24 h. Specifically, GM-HC activating PMS generated the active species, including sulfate radicals (SO₄•^–), singlet oxygens (¹O₂) and superoxide radicals (O₂•⁻), which speeds up the degradation of sulfentrazone. Five major degradation products of sulfentrazone and two possible degradation pathways were proposed. The C-Cl and C-CH₃ of sulfentrazone molecules are the initiation sites attacked by active species for degradation according to density functional theory (DFT) calculation. Additionally, after the sulfentrazone was degraded by GM-HC/PMS system, sulfentrazone-induced phytotoxicity to rice seeds and seedlings was significantly alleviated. This work presents a novel approach for addressing herbicide wastewater pollution.