Preparation of silica nanoparticles from geothermal sludge via sol-gel method

Silica geothermal is abundantly available as side products or waste from the production of energy from Geothermal Power Plants. These inexpensive waste materials was used to produce silica nanoparticles which in return increased the value of silica geothermal. The purpose of this research is to synthesize nanoparticle silica from geothermal waste following the sol-gel method. This was conducted by reacting silica waste with NaOH 1.5 N and subsequently the addition of 2N HCl solution to form a gel at pH 5. The ageing time of the gel were varied from 18 to 72 hours and the specific surface area were characterized by the Brauner Emmett Teller (BET) Adsorption. Aging time at 18 hours showed the highest specific surface area of 289 m²/g. The surface chemistry of the silica nanoparticles were performed using Fourier Transform Infra Red (FTIR) which showed that silanol dan siloxane groups were prominent. In contrast with its precursor, the silica geothermal waste, which was in its amorphous phase, the X-Ray Diffraction (XRD) of the silica nanoparticles showed high crystallinity.