Production of activated carbon by pyrolysis of rice husk of Vietnam

Abstract

Relevance of the work is caused by the need to utilize a large amount of husk formed at rice processing. The aim of the research is to determine the composition and structural characteristics of the solid carbon materials obtained by heat treatment of husk of rice grown in the Red River Delta (Republic of Vietnam). Methods: method of heat differential scanning calorimetry using a simultaneous thermal analyzer STA 449F3 Jupiter (Netzsch, Germany) combined with mass spectrometer QMS 403C Aёolos (Netzsch, Germany); electron microscopy (JEOL USA JCM-6000); ZAF method standardless quantitative analysis to determine the elemental composition; isotherm of hermal nitrogen desorption by using NOVA Station A device in accordance with the BET method and according to GOST 6217-74 to determine the porous structure characteristics (specific surface area - S, total pore volume - V[sigma], pore diameter - d). Results. Calcination of raw material at the temperature of 600 C results in significant decrease in oxygen content from 42,82 to 26,17 wt.%, increase in silicon content from 7,00 to 25,00 wt. %; the C/H ratio increases to 30 expectedly. Elemental composition and parameters of porous structure of rice husk, carbonizate, material after separation of SiO2 and activated carbon were investigated. Activation of the resulting material containing 10 wt. % of potassium carbonate at 900 C let obtain the activated carbon with specific surface area of 1329 m2/g and adsorption capacity of 0.811 cm3/g. Contribution of micropore surface to the specific surface area increases up to 60 % as a result of the carried out operations. The calculated C/H ratio reaches 84.

Keywords

• rice husk pyrolysis
• elemental composition
• carbonizate activation
• porous structure