Parametric effect of adsorption variables on CO2 adsorption of amine-grafted polyaspartamide composite adsorbent during post-combustion CO2 capture: A response surface methodology approach

In this study, effect of operating variables (e.g., temperature, flue gas flow rate and pressure) on the CO₂ adsorption capacity of an amine-grafted polymer composite adsorbent, PAA, was investigated using a statistical approach (response surface methodology). A set of 25 experiments were designed using the central composite design (CCD) and six regression models were proposed to describe the behaviour of the materials for CO₂ capture under the influence of the operating variables considered in this study. The best model that adequately described the behaviour of the material displayed a mean error, a variance and a p-value of -2.6375 × 10^-12, 29 and 0.0006, respectively, indicating the statistical significance of the model to describe the behaviour of the material during CO₂ adsorption. In addition, results of the cross-validation of the model showed an error of about 5%, strengthening further the validity of the model. Under the main and interaction effects of the considered variables, a maximum amount of CO₂ adsorbed was approximately 45 mg CO₂/g adsorbent at a gas flowrate of 60 ml/min, a temperature of about 40°C, and at a pressure of 1.6 bar.