CRYSTAL AND AMORPHOUS SILICA FROM KMnO4 TREATED AND UNTREATED RICE HUSK

In present research attempt has been made to determine effect of dilute solution of potassium permanganate on rice husk and the quality of amorphous silica obtained by controlled burning of treated rice husk. The rice husk was allowed to react with the dilute solution of KMnO4 (0.001N) at room temperature for half an hour. The treated and untreated rice husks were then analyzed by Scanning Electron Microscope (SEM) and by Thermogravimetric Analyses (TGA). The SEM results revealed that the cellulose and organic matters in the protuberances of the rice husk were partially dissolved into the solution of potassium permanganate. TGA of rice husks showed that the thermal degradation of potassium permanganate treated rice husk was relatively faster than the untreated rice husk due to the availability of oxygen from decomposition of KMnO4 and due to the reduced cellulose and organic contents. For X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectrometry (FTIR) analyses the pretreated rice husk was heated in tube furnace at 750 °C for one hour. FTIR results revealed that the O-Si-O bond in rice husk ash become weak due to the presence of potassium permanganate. Favorable results were obtained from XRD patterns indicating that potassium permanganate treated rice husk produced amorphous silica of good quality.