Journal of Chemical and Engineering Data, Vol.65, No.11, 5476-5482, 2020
Capturing Carbon Dioxide on the Wet SBA-15 Mesoporous Molecular Sieves with Different Surfactants
SBA-15 mesoporous molecular sieves were used as the adsorption medium to capture carbon dioxide by the gas hydrate method. First, it is confirmed that the synthesized SBA-15 material has a uniform pore size with the 77 K nitrogen adsorption-desorption isotherms and transmission electron microscopy analyses. Second, the effects of the capture of carbon dioxide on the SBA-15 material by adding different amounts of water were investigated. Each adsorption isotherm of the SBA-15 material with different presorbed water has a jump point, and the adsorption capacity of CO2 increased with the increase of the water-sample ratio (R-w, the mass ratio of the preadsorbed water and the dry SBA-15 material). At 2.5 MPa, the adsorption capacity of R-w = 2.0 is 20.14 mmol/g and that of the dry material is 3.86 mmol/g. The optimal water-sample ratio was determined to be 2.0. The formation of carbon dioxide hydrate of the jump point on the wet SBA-15 is verified by the enthalpy of capturing carbon dioxide. Finally, the effects on carbon dioxide hydrate formation at the wet SBA-15 material with different surfactants [SDS, sodium dodecyl benzene sulfonate (SDBS), and polysorbate 80 (Tween 80)] were investigated. The results show that the promoting effects of different types of promoters increase first and then decrease with increasing concentration. The optimal concentrations of SDS, SDBS, and Tween 80 are 1000, 1500, and 1000 mg/L, respectively. The wet SBA-15 with 1500 mg/L SDBS has the best promotion effect among the three surface surfactants.