Synthesis of mesoporous Silica SBA-15 from geothermal sludge

Abstract

The silica sludge from geothermal power plants has been prepared into silica products that potentially meet various industrial applications. The abundance of high-concentration silica in the sludge is interesting to ensure the availability of the raw material and support the environmental-friendly material processing. The present study aimed to synthesise mesoporous SBA-15 silica using sodium silicate from geothermal sludge without complicated purification. The sol-gel method and pluronic-P123 templating via a hydrothermal route were used to prepare the SBA-15 silica samples. The route was tested with commercially available sodium silicate. The sample powder was prepared using sodium silicate from geothermal sludge, using the route chosen from the successful synthesis route of commercial sodium silicate. The samples were then characterised and identified by FTIR, XRD, TEM, and BET. The sample prepared from the sludge has a specific surface area of 711.93 m2/g, pore volume of 0.85 cm3/g, pore size in diameter of 3.82 nm, micropore volume of 0.19 cm3/g, and N2-adsorption capacity of 604.64 cm3/g meanwhile the TEM images exhibit the hexagonal arrangement of pore structure as the special feature of SBA-15 silica.