Abstract
Pulping in agro-waste processes are known to affect the chemical constituents of the materials obtained. In this study, activated carbons (ACs) were prepared using precursors based on rice straw, rice husks and bagasse. The composition of these precursors was first determined in order to study the influence of the components of each of these precursors on the sorption properties of the ACs obtained. The ash content was determined by calcination of the precursors as the main component present in ashes is silica, which is known to play a role on sorption processes. The surface chemistry of the ACs was assessed by ammonia thermo-desorption (NH3-TPD), before being tested for carbon dioxide capture. ACs obtained from bagasse were capable of capturing up to 14 wt % at atmospheric pressure and 25°C, regardless of the pulping process applied to the precursor. Rice-husks based AC gave a similar result when the precursor was pulped with a 12% soda solution. Rice straw based ACs were less interesting in terms of CO2 capture. These differences were rationalized in terms of composition and textural properties.