Synthesis and Characterization of Mesoporous Silica from Algerian River Sand for Solar Grade Silicon: Effect of Alkaline Concentration on the Porosity and Purity of Silica Powder

In the present work, we report the successful extraction of high purity silica from the Algerian siliceous sand. We improved the chemical extraction process of silica using acid pretreatment before purification and studied the effect of sodium hydroxide (NaOH) solution molarity on the purity of as-obtained silica. X-ray diffraction, Energy-dispersive X-ray spectroscopy, and Scanning Electron Microscopy analyses were carried out on the samples before, during, and after chemical purification. The results show the improvement of the purity of the resulting powder with the change of the alkaline concentration. The results showed a decrease in the impurity concentration of the sand after acid leaching. The extracted silica has a purity of more than 99% and has an amorphous and mesoporous nature, confirmed by the mentioned analysis techniques, together with Fourier Transform Infrared Spectroscopy, thermogravimetric analysis, and the Physical Adsorption Analysis, which makes our chemical extraction method very promising, and the resulted silica is a good source to elaborate solar grade silicon used in photovoltaic applications.