Thermal destruction of rice hull in air and nitrogen

Study on the effectiveness of thermally treated rice husks for petroleum adsorption

“…7). The XRD pattern features two diffused peaks at 2 22°and at 2 44°, which corresponds to the presence of amorphous silica and graphite structures, respectively [35]. As seen from Table 1, the full width at half maximum (FWHM 2-Theta) is higher in case of the 400°C sample, which indicates a smaller size of crystalline carbon.…”

“…The double peak at 1453 and 1383 cm −1 corresponds to the -C-O groups stretching of carboxylates. The pronounced peak at 1089 cm −1 with high intensity is attributed to the stretching vibrations of siloxane groups [35]. Fig.…”

“…In detail, the weight percentage of silicon in rice husk increased from 19.4% at 300°C to 40.1% at 700°C, and the carbon content decreased from 32.6% at 300°C to 9.0% at 600°C but increased again to 12.3% at 800°C. This can be explained by the fact that higher temperatures cause the thermal decomposition of organic substances in the rice husks and hence the relative silica content increases [35]. Increasing weight percent of silica positively influences the petroleum sorption capacity of rice husk due to the good adsorbent properties of silica (SiO 2 ).…”

Magnesiothermic reduction of rice husk ash for electromagnetic wave adsorption

“…It is clear that the micropore volumes of RA400-800 are much lower than that of RN400-800 because of the closure of pores induced by surface melting of oxides during heating process and magnesiothermic reduction [45]. The BET surface area of RA400-800 from 16.2 m 2 g -1 at 400 o C to 18.6 m 2 g -1 at 800 o C, much lower than that of RN400-800, which generally decrease with temperature, from 342.9 m 2 g -1 at 400 o C to 182.9 m 2 g -1 at 800 o C. When the temperature of magnesiothermal reduction increase to 800 o C, the unreacted silica and alkaline oxide in the ash could form a liquid phase that induce the surface melting of rice husk, slightly reduce the BET surface area of RA800.…”

“…For RN800, the absence of carbon residue in RN800 may retard the liquid phase formation and more carbon residue was consumed in magnesiothermal reduction with silica and Mg to produce SiC result in more developed mesopore structure and BET surface area of RN800. In general, RN samples exhibit more developed porous structure than that of RA400-800, because of the presence of nitrogen for rice husk ashing have retained the carbon and retarded the surface melting and the formation of critobalite [45]. The frequency dependence of EM parameters of all samples were detected by using vector network analyzer at range of 2 -18 GHz.…”