Computational and experimental studies on the CO2 adsorption of layered double hydroxide intercalated by anionic surfactant

The Mg[sbnd]Al, Ca[sbnd]Al, Zn[sbnd]Al and Mg[sbnd]Fe layered double hydroxides intercalated by sodium dodecyl sulfate was prepared by a co-precipitation method. These materials were characterized by elemental analysis, Powder X-ray diffraction (XRD) and N2 physical adsorption and desorption. Adsorption of CO2 on the samples was investigated by thermogravimetric analysis at 30 °C under 1 bar. The samples had a CO2 adsorption capacity in the range of 0.35–0.58 mmol/g. Ca[sbnd]Al layered double hydroxide intercalated by sodium dodecyl sulfate (SDS) had the highest CO2 adsorption capacity. The layered structures were analyzed by using quantum chemical calculation methods. The simulation results showed that CO2 adsorption capacity was correlated to the ELUMO and the density of Lowest Unoccupied Molecular Orbital (LUMO). The higher ELUMO and density of LUMO orbitals promoted the formation of O-H…O hydrogen bonds, which leaded to the higher CO2 adsorption capacity.