Activated carbon from cotton stalks by impregnation with phosphoric acid

摘要

Dried, crushed cotton stalks were impregnated with varying concentrations of phosphoric acid (20-85 wt./100), dried at 383 K and carbonized at 773 K for 2 h. Porosity was determined by analysis of N_2/77 K adsorption isotherms. High adsorbing carbons with well developed mesoporosity were obtained. Analysis for microsporosity, by the α_S-method, proved the presence of minor content in all products. Non-dried impregnated precursor produced a carbon with much lower adsorption capacity, whereas carbonization at 673 K furnished a carbon with comparatively lower texture parameters. TG analysis of the acid-impregnated precursor exhibited considerable modification in the pyrolysis characteristics. The effect of activant was associated with its effect as dehydrant, shift in decomposition to higher temepratures, suppression of volatiles, and space left by its leaching thereafter.