Study of CO(2) Adsorption on Chemically Modified Activated Carbon With Nitric Acid and Ammonium Aqueous

The study of CO(2) adsorption on adsorbent materials is a current topic of research interest. Although in real operating circumstances, the removal conditions of this gas is carried out at temperatures between 290 and 303 K and 1 Bar of pressure or high pressures, it is useful, as a preliminary approach, to determine CO(2) adsorption capacity at 273K and 1 Bar and perform a thermodynamic study of the CO(2) adsorption heats on carbonaceous materials prepared by chemical activation from African palm shell with CaCl(2) and H(3)PO(4) solutions, later modified with HNO(3) and NH(4)OH, with the aim to establish the influence that these treatments have on the textural and chemical properties of the activated carbons and their relationship with the CO(2) adsorption capacity. The carbonaceous materials were characterized by physical adsorption of N(2) at 77K, CO(2) at 273K, proximate analysis, Boehm titrations and immersion calorimetry in water and benzene. Activated carbons had a BET area between 634 and 865 m(2)g(−1), with a micropore volume between 0.25 and 0.34 cm(3)g(−1). The experimental results indicated that the modification of activated carbon with HNO(3) and NH(4)OH generated a decrease in the surface area and pore volume of the material, as well as an increase in surface groups that favored the adsorption of CO(2), which was evidenced by an increase in the adsorption capacity and the heat of adsorption.