Aerogel powder production and characterization from silica based natural raw and waste materials

In this current study, it was purposed to produce silica aerogel powder using natural silica based raw materials (perlite, zeolite, pumice, quartz) and waste materials (window glass, borate, soda bottle glass dust) by sol-gel method. In the prepared NaOH solution, silica source powders were dissolved by reflux process and then filtered to obtain a sodium silicate solution. The pH of the solution was neutralized using HCl acid and the first step of the aging process was initiated at room temperature in the closed position. The aging process was continued as the volume in the %20 H2O/Ethanol, %70 Ethanol/TEOS and n-heptane for 1 day with keeping in oven. Surface modification with TEOS (tetraethylorthosilicate) was carried out at the aging stage in order to strengthen the bonds in the silica aerogel structure and to increase the material strength. The final of aging step, the liquid in the gel structure was removed by drying under atmospheric pressure for a period of time determined at different temperatures, and finally silica aerogel powders were produced at room temperature. The obtained silica aerogel powders was characterized using SEM, FESEM, EDS, XRD, DTA, FTIR, XRD and BET devices and the properties of silica aerogels produced from different natural and waste materials are comparatively detailed. According to the characterization results achieved in this thesis research; they were found that silica aerogels have very low density due to the three-dimensional and porous network and high porosity values with porous spongy structures made up of millions of holes with SEM, FESEM analysis; endothermic peaks were observed from dehydration, decomposition reactions and exothermic peaks were observed from oxidation with DTA analysis. The FTIR analysis showed that Si-C peaks originated from vibration, strong and prominent Si-O-Si peaks originating from asymmetric and symmetrical bonds of molecules and movement of the bonds, C-H peaks originated from adsorption and O-H adsorption peaks originating from physically adsorbed water. Surface area, pore volume, pore diameter, nanoparticle size results and adsorption-desorption isotherm curves of the powders were obtained by BET analysis.