Hydrotalcites as advanced materials for adsorptive removal of heavy metals from wastewater

Access to safe drinking water is a basic human need and a necessity for optimum health. However, over the past years, water quality has decreased due to pollutants that are introduced into the water bodies (rivers, lakes, seas, and groundwater). Researchers have reported that heavy metals such as Cd, Pb, As, and Tl, among others, are the dominating contaminants in water bodies. Heavy metals are highly bioaccumulated, and when they are introduced into water bodies, they become toxic, threatening the health of both human and aquatic life. Because of their high toxicity, it is crucial for them to be eliminated from the water bodies. Several methods have been used to remove heavy metals from wastewater, and adsorption is regarded as a promising method for extracting these heavy metals from water because it is highly efficient and low costs. Among materials used in adsorption, hydrotalcites (especially layered double hydroxides (LDHs)) have gained much attention as adsorbents for removing heavy metals from wastewater. This chapter discusses recent developments in the application of hydrotalcites in the adsorptive removal of heavy metals in wastewater. The physicochemical properties and their influence on the adsorptive mechanisms of LDHs are also discussed in detail.