Environmental Chemistry and Engineering

Recently a group of solid adsorbent known as the graphene-based adsorbents has been developed by the scholars to reduce the adsorbent cost and enhance CO₂ capture. As a result of the unique combination of graphene's chemical, mechanical, structural and thermal properties, these adsorbents have some advantages in comparison with other adsorbents. Determination of pure CO₂ capacity on graphene-based adsorbents has been the main target of the researches. Therefore, there is a literature gap to estimate CO₂ adsorption capacity on these adsorbents in the binary or multi gas system which has different CO₂ partial pressures similar to CO₂ concentration in the flue gas of thermal power plants especially combined cycle power plants. In this study, an experimental model for calculation CO₂ working capacity on mesoporous graphene oxide-TiO₂ nanocomposite has been developed by response surface methodology based on the results of the breakthrough experiments (Figure 1 and 2) with respect to CO₂ concentration in the flue gas of combined cycle power plants (including, 3.109, 4.352 and 5.102% vol) and different temperatures (including, 25, 60, 95^oC) and various flow rates of feed gas (including, 20, 40 and 60 ml/min). CO₂ working capacity as the function of the above parameters has been illustrated as follows: CO₂ capacity=0.27644+ 0.06429 C-0.08541 T 0.02464 C²+0.02378 F²-0.01966 C×T-0.04669 T×F. Increase of CO₂ concentration and the gas flow rate have the positive implication on CO₂ working capacity. On the other hand, the gas temperature has the negative effect on CO₂ adsorption as a result of exothermic behavior of CO₂ capture. Furthermore, this parameter has the most negative effect on the experimental model of CO₂ working capacity. The interaction of the parameters including C×T and T×F has the negative implication on CO₂ working capacity.