Fabrication strategies and Cr(VI) elimination activities of the MOF-derivatives and their composites

Hexavalent chromium (Cr(VI)), as one of the hazardous heavy metals, has attracted increasing attention due to its toxicity, carcinogenicity along with the threat to the health and safety of aquatic organisms. The Cr(VI) removal methods mainly include adsorption and catalytic reduction. Metal-organic frameworks (MOFs) exhibit some merits like large surface area, inherent porous structure and adjustable topology. MOF-derivatives like porous carbon, metal oxides and metal sulfides can retain the merits of their MOFs precursors, which have been used in adsorption, catalysis, as well as energy storage and conversion. This review presented the state-of-the-art status of the MOF-derivatives and their composites for the purpose of Cr(VI) removal, in which the Cr(VI) removal mechanisms over the various MOF-derivatives and their composites were carefully introduced. Finally, the challenges and prospects of MOF derivatives and their composites in Cr(VI) removal from water were proposed.