Freshly formed elemental sulfur-sulfidated zero-valent manganese for enhanced chromium(VI) removal from wastewater

•SZVMn is prepared using sulfidation with freshly formed S0 as sulfidizing agent.•Efficient removal of Cr(VI) by SZVMn: maximum capacity of 190.8 mg/g.•SZVMn surpasses nZVMn in terms of matrix resistance and long-term storage ability.•Low S/Mn molar ratio at 0.1 in material synthesis is beneficial to Cr(VI) removal.•Cr(VI) is rapidly reduced by Mn0 and later by dissolved/surface-bound Mn2+.