Application And Synthesis Of Silica-Based Aerogels For The Removal Of Persistent Organic Pollutants From Water: A Review
Date
2025Author
Odongo, Irene Akinyi
Njoroge, Peter Waithaka
Opiyo, Sylvia Awino
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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
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