Effect of process variables on adsorption characteristics of activated carbons from sugar cane bagasse.

J. BLANCO CASTRO; P. R. BONELLI; E. G. CERRELLA; A. L. CUKIERMAN

SEVILLA, ESPAÑA

Congreso; 1st. World Conference and Exhibition on Biomass for Energy and Industry.; 2001

Conversion of sugar cane bagasse into activated carbons constitutes an attractive alternative to transform this copious waste into a useful product. Activated carbons from bagasse were prepared by thermal treatment of the residue impregnated with phosphoric acid under a self-generated atmosphere. The effects of varying the weight ratio of phosphoric acid to precursor (R), the thermal treatment temperature and the carbonisation time on the developed pore structure of the resulting carbons were examined. Textural features of the carbons were characterised from nitrogen adsorption measurements. A progressive development of the adsorption capacity takes place with increasing temperature up to 500 °C, attaining a maximum surface area of around 1130 m2/g for R=1.5 and 1 hour. At a higher temperature, a considerable reduction in adsorption capacity occurs likely due to structural contraction. Increasing R or varying carbonisation time leads to detrimental effects, decreasing adsorption capacity. Distinctive surface features were visualized for the carbons obtained under different conditions by SEM. Carbons showing the best surface properties were additionally tested towards the removal of some species from solution and compared with a commercial sample. The selected carbon results in a high-quality product with adsorption characteristics comparable to the commercial sample.