Functionalized Metal-Organic Frameworks for Hg(II) and Cd(II) Capture: Progresses and Challenges.

Mercury and cadmium are deemed to be the most harmful heavy metal ions for elimination due to their persistent bio-accumulative and bio-expanding toxic effects. Although many technologies have been developed for capturing Hg(II) and Cd(II) ions from aqueous solution, developing efficient and practical capature technology remains a big challenge. Metal-organic frameworks (MOFs) have been considered as the most promising adsorbents for Hg(II) and Cd(II) removal due to their high porosity and easy functionalization, and various of MOF-based adsorbents based on different synthetic strategies have been prepared and studied. In this article, the progresses of MOF-based absorbents for Hg(II) and Cd(II) capture are described according to the synthetic strategies and the types of functional groups, and the comparison and practical analysis of various adsorbents are also presented.