Investigation of the effect of alumina-aerogel support on the CO2 capture performance of K2CO3

This study investigates a novel technique for the synthesis of alumina-aerogel-supported K2CO3 sorbent with remarkably high CO2 capture capacity and stability. The alumina-aerogel support exhibited a significantly high BET surface area of 2019 m(2)/g, which has never been attained in previous studies for an alumina-based material. The synthesized alumina-aerogel was supported on K2CO3 for use in the post-combustion CO2 capture process for the first time. The study examines the effect of various synthesis variables on the physical properties of the support, such as types of alcohols, solvent-to-co-solvent ratios, and ageing times. The highest BET surface area (2019 m(2)/g) was obtained using methanol as the solvent, at a solvent-to-co-solvent (methanol-to-toluene) ratio (v/v) of 1/5, and after five-day aging time. Using the response surface methodology, the effect of carbonation temperature and H2O-to-CO2 flowrate ratio on the CO2 capture capacity of the sorbent was modeled. Based on R-2, R-adj,(2). RMS and MAE values (0.9509, 0.9159, 0.6532 and 0.7363, respectively), the model demonstrated high accuracy in predicting the response. According to the models F-values and P-values, the effect of H2O-to-CO2 flowrate ratio on the CO2 capture capacity was more dominant than the carbonation temperature. The optimum levels of carbonation temperature and H2O-to-CO2 flowrate ratio were 56.1 degrees C and 1.1, respectively. Under the optimum condition, the CO2 capture capacity of the sorbent (based on 50 wt% support/K2CO3) reached the significant value of 7.2 mmol CO2 per gram of K2CO3 after 30 mins of carbonation time, which is equal to the theoretical CO2 capture capacity of K2CO3. The CO2 capture performance of the sorbent remained stable during 20 carbonation and regeneration cycles.