Exploring behavior of Clinoptilolite@Graphene oxide compositeas a novel adsorbent for CO2 capture

Graphene oxide is an ideal base for solid adsorbents to capture CO2. In this study, two materials, Clinoptilolite and Graphene oxide (GO), were used to prepare Clin@GO by autoclave at constant temperature and pressure. The response surface methodology based on the Box-Behnken design was applied to predict maximum adsorption capacity under optimum conditions. The highest adsorption capacity was 9 mmol/g achieved at 30 °C, 3.09 bar, and 0.25 g of adsorbent weight. The results of the isotherm study reveal that the Sips model has a high value of R2. The Elovich kinetic model can describe experimental data showing the adsorption process on heterogeneous surfaces. The thermodynamic study results proved that the CO2 adsorption process by Clin@GO is a physisorption and exothermic process. The mass transfer study disclosed that the mass transfer coefficient, diffusion coefficient, and mass flux values for CO2 molecules as a gas phase in the single-component system are 0.9249 m/s, 0.00082 m2/s, and 0.00042 mol/m s, respectively.