Recent advances in heavy metals uptake by tailored silica-based adsorbents

In the last decade, numerous designed adsorbent materials like metal-organic frameworks (MOFs), covalent organic frameworks (COF), carbon nanotubes (CNTs), etc. have been developed and investigated for metal ions extraction applications in the contaminated aquatic environment. These materials are facing the problems associated with large-scale production, cost, stability, and reusable. Conventional adsorption like carbon and silica is still valuable and is in use for industrial applications. In the last decade, silica has gone through a lot of alteration and modification to enhance its efficiency for heavy metal adsorption. In this review, the tailoring of the silica properties by surface functionalization or developing new hybrid composites for the scavenging of the heavy have been summarized. Silica functionalization with various organic functional groups, composites like silica/polymers, silica/metal oxide, silica aerogels, etc., has been explored. Moreover, interpretations of the effective metal uptake mechanisms associated with metal ions adsorption onto silica adsorbents are also investigated. Overall, the review offers comprehensive insights into the interface between metal ions and silica-based materials.