Application And Synthesis Of Silica-Based Aerogels For The Removal Of Persistent Organic Pollutants From Water: A Review

Abstract

Background: Water contamination is a major global issue that necessitates the development of new and sustainable purification technologies. Aerogels, ultra-light porous materials with a large surface area and unique properties, have emerged as promising candidates for water treatment, particularly in removing organic contaminants. These materials are highly porous and low-density foams with a microstructure consisting of nano-sized pores and interconnected primary particles. Materials and Methods: The sol-gel synthesis of silica aerogels involves hydrolyzing a silica precursor such as tetraethyl orthosilicate (TEOS) in the presence of a catalyst to form a sol, which undergoes condensation reactions to create a three-dimensional siloxane (Si–O–Si) network. This sol gradually transitions into a wet gel, which is then aged to strengthen the structure. The solvent within the gel is carefully replaced with a low surface tension liquid, often ethanol, to minimize damage during drying. Various methods are used to dry the gel while preventing collapse of the delicate network. Results: Silica aerogels are excellent adsorbents for removing organic pollutants like PCBs because of their high surface area, ultra-high porosity and tunable pore sizes, which enhance contact and diffusion of pollutants. Conclusion: Their elemental composition and structural properties can be precisely tailored using the sol-gel method, enabling the efficient adsorption and degradation of organic pollutants from water sources