The effect of calcination temperature on the synthesis of magnetic silica nanoparticles from geothermal sludge

摘要

Geothermal sludge is a waste from geothermal power plants (PLTP) with very high silica content. Geothermal sludge waste is potential as a basic material in the synthesis of silica nanoparticles. The research was conducted using FeCl_3 salt as Fe ions precursors forming the silica magnetic nanoparticles. This was obtained by reacting silica waste with NaOH 1,5 N at 90°C, added with 1,6 gr FeCl_3 and subsequently adding 2N HCl solution to form a gel at pH 5 and aging for 18 hours. The calcination temperature of the samples were varied at 400°C, 500°C, 600°C and 700°C. Characterization of magnetic silica nanoparticle included Brauner Emmet Teller (BET) to determine the surface area, X-Ray Diffraction (XRD) for phase identification and morphology of the nanoparticles was characterized Transmition Electron Mycroscope (TEM). The results showed that samples calcined at 400°C was in its amorphous phase and has the highest surface area of 658.11 m~2/g.