چكيده به لاتين
Today, the tendency to use hypercrosslinked polymers (HCPs) adsorbents has increased due to its low cost for removal of the flue gas of fossil-fuel power plants. The main objective of this work is to synthesize carbazole-based hypercrosslinked adsorbent to capture CO2 in a batch reactor and optimize adsorbent through post-synthesis modification to improve adsorption capacity. Structural characteristics of the adsorbent were studied using various techniques including FTIR, BET and EDS. Response surface methodology (RSM) was employed to optimization the synthesis parameters and three factors of synthesis time, crosslinker ratio and catalyst type, in the range of 8-18 h, 1-4 and two Lewis acid catalysts, Fecl3 and Alcl3, respectively, as input variables and absorption capacity (mg/g) and adsorption percentage were considered as responses. The optimum operating conditions of temperature and pressure were considered to be 25 °C and 5 bar, respectively. The optimum amount of synthesis parameters for carbazole-based hypercrosslinked on synthesis time, crosslinker ratio and catalyst type were 11.2 h, 2.7 and Fecl3 as the optimum catalyst and adsorption capacity is 191.22 mg/g, respectively. Furthermore, additional experiments were performed to examine the isotherm and kinetic models and the thermodynamic parameters of absorption. For the carbazole-based hypercrosslinked adsorbent, the isotherm model is consistent with the Hill isotherm model, which indicates the equilibrium of the adsorbent bond with the adsorption sites and the interaction of the sites. The study of kinetic models showed that for the carbazole-based hypercrosslinked sample, the Elovich kinetic model is the best fiting with CO2 adsorption data. Finally, feasibility of the adsorption process were determined by thermodynamic modelling and enthalpy, entropy and Gibbs free energy differences of adsorption at 298.15 k and 5 bar were calculated -15.035 kj/mol, -0.025 kj/mol.k and -7.822 kj/mol, respectively.
