ランタン(La)ドープ-シリカ材の二酸化炭素(CO2)吸着メカニズムに関する考察

Abstract

Lanthanum (La) nanoparticle-dispersed amorphous silica (Si-O) powders were synthesized from chemical solution precursors. Then, in order to investigate the carbon dioxide (CO2) absorption and permeability mechanism La-dope silica, the relation between the microstructure of La nanoparticle-dispersed in amorphous Si-O powders specimen and CO2 absorption amount were measured and studied. As a result, CO2 adsorption property of the silica showed excellent data at lower temperature (100 C) in comparison with the high temperature (400 C). Moreover, the increase amount of the reversibly adsorbed CO2 was the highest for the composite samples Si content with a La/(Si-La) ratio. (Si : La = 4 : 1> 2 : 1). Calculating the diameter and volume of La nanoparticle in amorphous Si-O, a unique reversible CO2 adsorption property of La-doped silica was dependent on the surface are of LA2O3particle in Silica. This finding strongly suggested that when this La-Si-O composite material is used in the form of gas separation membrane, the reversibly CO2 adsorbed property is thought to contribute to the additional increase in the number of active surface sites of La2O3particle, which leads to a selective enhancement in the CO2 permeability.