Utilization of Rice Husks into Biochar and Nanosilica: For Clean Energy, Soil Fertility and Green Nanotechnology
Marilou M. Sarong, Ricardo F. Orge, Paul Jhon G. Eugenio, Juvy J. Monserate
Abstract
Rice husks are often dumped and burned in the field that emits greenhouse gases. Through green nanotechnology, developing these materials into diverse applications will not only create an avenue for new ideas and innovations but also beneficial to the environment. Thus, this study aimed to utilize rice husks in an eco-friendly way. Rice husks were converted into rice husk biochar (RHB) through continuous-type rice husk pyrolizer (CtRHP) which produces two important products: heat energy and biochar. High grade RHB was used as an amendment for degraded acid upland soil (Annam series) grown with corn. Plant height and biomass, and total N uptake, increased linearly with increasing rates of RHB levels. A linear trend of the effects of RHB on soil pH (water), and total N with the increasing RHB rates while soil pH and OC had a quadratic trend. The produced RHB were further derivatized into nanosilica (nSi). Characterization of nSi through SEM micrographs showed a cloudy-like structure with various particle sizes ranging from 5 to 20 nm, while XRD analysis revealed that the synthesized nSi is amorphous. Converting RHB into nSi will have various industrial applications such as catalysts, electronic and thin film substrates, and humidity sensors.