A systematic review of metal organic frameworks materials for heavy metal removal: Synthesis, applications and mechanism

Worldwide rapid urbanization and development accelerate anthropogenic heavy metals release and dispersion from local to broader areas, posing serious threats to aquatic ecosystems and human health. Although removing various heavy metal ions in aqueous solutions is well explored, current approaches on how to treat heavy metal pollution efficiently and pertinently still need improvement. Adsorption has been identified as the best technique for heavy metal removal, while metal–organic frameworks (MOFs) were considered to be one of the most promising emerging adsorbents capable of addressing complex environmental problems and possessing excellent adsorption properties. Therefore, the synthesis techniques, functionalization methods, and adsorption mechanisms (including adsorption kinetics, adsorption isotherms, etc.) of MOFs to provide optimal solutions for the design, synthesis, and optimization of MOFs were comprehensively reviewed in this work. In addition, a detailed overview and comparison of the applications of pristine MOFs, functionalized MOFs, and MOFs complexes in the removal of heavy metals are also carried out, from which we summarize the adsorption characteristics of various MOFs and give prospects for the development of MOFs. In brief, this review offers a detailed summary of the current information on the removal of heavy metals by MOFs, aiming to provide a strong reference for the synthesis of MOFs and a feasible solution for heavy metal treatment.