Production of Activated Carbon and Precipitated White Nanosilica from Rice Husk Ash

This work presented the preparation of rice husk ash (RHA) by Open-field burning and by combustion at 1000 oC for 4 hrs. X-ray diffraction studies of produced RHA revealed that increase in temperature of burning will increase the crystal growth rate with the occurrence of different varying degrees of quartz (Q), Cristobalite (C) and Tridymite (T). The purity concentration of silica in RHA samples were measured by X-Ray Fluorescence and found to be in the range of 82.7-91.6 % with major impurities of K2O, P2O5 and Cr2O3. RHA produced via open-field burning was treated with an activating reagent sodium hydroxide (3.5 mol/L), the activated rice husk so obtained was heated at a temperature of 900°C to get activated carbon. Silica was precipitated from sodium silicate by acidification using sulphuric acid with a percent yield 97% of extracted silica. Infrared spectral data supported the presence of hydrogen bonded silanol group (Si–O–H) and the siloxane group (Si–O–Si) in RHA and precipitated silica and reflects the high purity of precipitated white nanosilica (PWNS).