Influence of Surfactants on the Physical Properties of Silica Nanoparticles Synthesis via Sol-Gel Method

Silica nanoparticles (n-SiO2) have been synthesized using hydrolysis of Tetraethyl orthosilicate (TEOS) as starting material and ethanol as solvent by sol-gel method. The effect of different surfactants such as non-ionic surfactants sorbitan tristearate (Span 65) and sorbitan trioleate (Span 85) and anionic surfactants Sodium dodecyl sulfate (SDS) and emulsifier T-80 (Tween-80) on morphology and size of the particles was investigated. The role of these surfactants in controlling the size and properties of silica nanoparticles has been discussed. The particles size of silica nanoparticles is controlled also using Ammonia as base catalyst. Silica nanoparticles with average particles size 18 nm have been synthesized with span 65. Various analytical methods, i.e., scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV- visible absorption spectroscopy and X-ray diffraction (XRD) were used to comprehensively characterize the obtained silica nanoparticles. The synthesized Si NPs has been used for adsorption of uranium from aqueous waste solution and the best conditions were achieved at pH 4.0. The adsorption isotherms were described by means of Langmuir and Freundlich isotherm models. The maximum sorption capacity of the prepared Si NPs and experimental results showed this to be 20.6 mg.g^-1.