Sulfur‑vacancy‑rich FeS/biochar activates peroxydisulfate for highly efficient degradation of 1,4‑dithiane in water: Transformation and ecological toxicity reduction mechanism - Xinyuan Sun; Pengfei Guo; Yinjie Zhang; Tingting Zhang; Jie Gao; Guangbo Qu; Sanping Zhao; Yongbing Zhu (Journal of Environmental Sciences, 2026)