Recent development in processing technology on nanobiosilica by-product

Abstract

Nanobiosilica constitutes a product from rice husk ash processing. Silica has been prepared through alkaline extraction and precipitates separation processes. During the processing of nano biosilica, a considerable amount of residue was formed, this by-product must be utilised. From the mass balance of rice husk ash extraction, 90% silica from rice husk ash has been generated as well as around 10% residue containing carbon and minor other mineral composition. This research aimed to develop agroindustrial products from the residue of nanobiosilica processing for the removal of colour and odour from water. The residue was carbonised at 800 oC after chemical activation. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) were used in characterising the adsorbents. The results showed that the residue of nanobiosilica extraction still contained huge amount Si02. SEM characterisation revealed that microporous space on the surface of the adsorbents increased significantly after activation. XRD patterns showed that the adsorbent contains 61-73% crystalline and the BET surface was significantly different from iodin adsorption results. However, the composites maintained high surface area after chemical activation, hence it could be used as adsorber to apply in water purification applications. The colour and odour removal application represents an alternative bio adsorbent that could be used in water treatment.