Ammonia Activation of Carbonized Polysaccharides and their Application for the Carbon Capture

Porous carbons derived from polysaccharides (cellulose, chitosan, and alginic acid) have been prepared by heat treatment under N₂ atmosphere and activated at high temperature under ammonia gas atmosphere. The CO₂ adsorption capacities of prepared porous carbon materials and their dependence on the surface area and pore volume were investigated. The surface area of pristine carbon from cellulose, chitosan, and alginic acid at 800 .deg. C was measured as 406.5, 206.8, and 258.2 m²/g with the pore volume of 0.27, 0.14, and 0.15 cm³/g, respectively. The surface area and pore volume of carbons derived from cellulose, chitosan, and alginic acid further increased up to 976.6, 883.4, and 1031.9 m²/g and 0.54, 0.45, and 0.65 cm³/g, respectively, after the activation at high temperature under ammonia gas environment. The CO₂ adsorption capacities of pristine carbons were measured as high as 1.85 mmol/g and further increased up to 2.44 mmol/g by ammonia activation.