Optimized caged silica synthesis with lithium chloride and calcium chloride impregnation for prospective desalination application

Abstract

Caged Silica is an inorganic sorbent that is widely employed in a variety of applications, including catalysts, thermal insulation, energy storage batteries, and as an adsorbent in the extraction of fresh water. Researchers have devised several techniques to prepare mono-dispersed caged silica with standard morphology. Template synthesis is quite prominent due to its structural stability and versatility. In this work, we present synthesis of caged silica microsphere via hard template synthesis by employing the process of calcination at 550 • C for 4 hours at the rate of 3 • C/min and subsequent drying. Emulsion polymerization was utilized to develop the polystyrene required in the procedure. This study also looks at how different parameters like silica precursor concentration, surfactant concentration, and catalyst concentration affect silica morphology. It was investigated that caged silica synthesis was optimized at 1.5ml of TEOS, 1.25g of CTAB, 0.1g of PS and 75µl of NH 3 which was confirmed by SEM and TEM analysis. Surface area of caged silica was measured as 448m 2 /g with the stirring rate of 5 minutes. We also impregnated caged silica with 9% of hygroscopic salts (CaCl 2 and LiCl) and it showed substantial uptake improvement. Preliminary results showed that LiCl impregnated caged silica is more efficient at water uptake compared to CaCl 2 . The proposed composite adsorbent (Si-9-Li & Si-9-Ca) could be used for the desalination application.