Influence of Pretreatment with Soda (NaOH) on the Structural Characteristics of Activated Carbon Prepared by Chemical Means with Hsub3/subPOsub4/sub from Rice Bran

摘要

The purpose of this work is the preparation of best activated carbons from rice bran through carbonization at 500°C preceded by an impregnation in a 25% Hsub3/subPOsub4/sub solution. We carry out the study of the effects of pretreatment with soda and Xp impregnation ratio on characteristics of three series of activated carbons SRsub0N/sub, SRsub1N/sub and SRsub2N/sub corresponding to the pre-treatment with soda 0 M, 1 M and 2 M respectively. The iodine value and the textural properties of prepared carbons have been determined. The maximum iodine value, 893 mg.gsup-1/sup is obtained in the SRsub2N/sub series for Xp = 2.5. In the SRsub1N/sub series the maximum iodine value 866 mg.gsup-1/sup is obtained for Xp = 4. Also activated carbons CSsub1/sub (SRsub1N/sub - Xp = 4) and CSsub2/sub (SRsub2N/sub - Xp = 2.5) have the following characteristics: specific surface area equal to 1711.6 and 1558.5 msup2/supgsup-1/sup and porous volumes of 1.234 and 1.385 cmsup3/sup/g respectively. Studies conducted on phenol adsorption and thermodynamic showed that CSsub1/sub is slightly more effective than CSsub2/sub with a spontaneous and exothermic reaction. On the other hand, their adsorption isotherms are best described by the Langmuir model than that of Freundlich.