Recent advances in the detection and removal of heavy metal ions using functionalized layered double hydroxides: a review

Heavy metal pollution is one of the most severe environmental problems, possessing high ecotoxicity and health risk. Therefore, it is important to develop effective methods and corresponding materials for the detection and removal of heavy metals. Recent studies reveal the great potential of layered double hydroxides (LDHs) in detecting and removing heavy metals owing to their designable structure and tunable surface composition. In this review, we majorly discuss the recently adopted detection and removal of heavy metal ions based on LDHs. This review starts with an introduction of the structural characteristics and functionalization of LDHs. Then, the sensing tactics and mechanisms are introduced regarding LDH-based heavy metal ion detection. Based on the type of interaction, the removal of heavy metal ions with LDHs is summarized into two categories: reversible adsorption and irreversible mineralization. This review ends with a discussion on the challenges and future trends of LDH-based detectors and adsorbents for heavy metal ions.