Precipitated Silica from Wheat Husk

Abstract

In present investigation extraction of amorphous silica from wheat husk and then converting it into precipitated silica by using sodium hydroxide has been  studied at various Na/Si ratios and reaction time. Wheat husk was calcined in electric tube furnace at 500 0 C for two hours to produce wheat husk ash (WHA). XRD of WHA confirmed its amorphous nature. The WHA was treated against sodium hydroxide at different molar ratios and reaction time to obtain sodium meta silicate. Each time sodium meta silicate was treated against 0.1N HCl to recover silica in precipitated form. XRD and FTIR results confirmed the amorphous nature of precipitated silica. It was also observed that one hour boiling with molar ratio Na/Si =2 is sufficient for optimum conversion into sodium meta silicate.