Adsorptive removal of heavy metal anions from water by layered double hydroxide: A review. (September 2022) - Dong, Yuecen
Abstract: High-valence heavy metals with high ecotoxicity are generally found in water in the form of anions, and this increases heavy metal pollution intensity and treatment difficulty. Recent studies have pointed to the potential efficiency of layered double hydroxides (LDHs) to meet this challenge. In this review, we retrospectively research the development of LDHs using a Java application called CiteSpace. We describe the unique layer structure, highly adjustable chemical properties, and diverse synthesis methods of LDHs, all of which decide the effective adsorption of heavy metal anions by LDHs. Subsequently, we focus on discussing the adsorption mechanism of LDHs on heavy metal anions, as well as the current state of research and future directions for microscopic interaction mechanisms. For practical applications, it is critical to improve the adsorption selectivity and stability. We then recommend solutions to improve the adsorption selectivity and stability after identifying the influencing mechanism. Finally, we provide our perspectives on the future development of LDHs adsorption of heavy metal anions. Graphical abstract: Image 1 Highlights: A co-citation analysis of layered double hydroxides studied in environmental field is carried out. Adjustable structural properties and diverse synthesis methods of layered double hydroxides are discussed. Adsorption mechanism of LDHs on heavy metal anions is multifaceted and deserves further exploration. Solutions to improve the heavy metal anion adsorption selectivity and stability of LDHs are summarized and recommended.