Hydro Thermo-Baric Processing and Properties of Nano Silica from Rice Husk

Several processing methods have been used to obtain silica from rice husk with a
persistent problem of lack of scalability from laboratory scale to levels of production necessary for
commercial or industrial applications, at low cost. To address this draw-back, a novel methodhydro
thermo-baric process, was developed and used to process high purity silica from rice husk.
Since the suitability of rice husk silica in a given application is dependent on the nature of its
structure and morphology and the two parameters are affected by the processing methods used in
obtaining the silica, this paper reports the preliminary studies done on the silica obtained from this
novel method using XRF, XRD, FESEM and EDX. XRD results show that the silica produced,
which by XRF analysis had purity approaching 98%, is amorphous in nature. FESEM images
showed that the particles have nanometric size. However, EDX results show an increase in residual
carbon in the silica, with increase in the processing temperature. BET analysis showed an increased
surface area from 21.42m2/g to 133.94m2/g for the untreated and treated samples, respectively.