Comparison of the Performance of Improved Activated Carbon and Alumina Adsorbents with Hydroxide Solutions to Enhance Carbon Dioxide Adsorption

In the present study, active carbon and active alumina adsorbents were improved using sodium hydroxide and potassium hydroxide solutions in order to increase the absorption of carbon dioxide. The effect of different operating parameters including the amount of adsorbent, concentration of hydroxide solution, temperature, and pressure on the adsorption process were investigated. The results of the adsorption experiments showed that the carbon dioxide absorption capacity increases by decreasing the temperature and increasing the pressure. The optimum conditions were 20 ° C, 6 bar, 2 g of adsorbent with 30% weight sodium hydroxide and potassium hydroxide. The maximum carbon dioxide absorption capacity for activated carbon modified with sodium hydroxide and potassium hydroxide solutions were 104.42 mg/g and 84.8 mg/g, respectively, which indicates 83 and 48 percent increase for modified activated carbon in comparison with unmodified ones. The carbon dioxide absorption capacity for activated alumina modified with sodium hydroxide and potassium hydroxide solutions were 146.70 and 130.84 mg/g, respectively, which indicates 47 and 65 percent increase for modified activated carbon in comparison with unmodified ones. As a result, generally, the modified activated alumina adsorbent revealed higher carbon dioxide absorption capacity carbon in comparison with the modified activated carbon.