The activity of Mg-Al layered double hydroxides intercalated with nitrogen-containing anions towards the removal of carbon dioxide from natural gas

Abstract

Magnesium-aluminum layered double hydroxides (Mg-Al LDH) with different metal concentrations are prepared using homogenous precipitation by urea hydrolysis. Mg-Al LDH are synthesized at temperatures ranging from 80 °C to 100 °C. The results obtained from elemental chemical analysis, X-ray diffraction, Fourier transform infrared spectra, and thermal analysis indicate the presence of intercalated urea-derived anions as well as carbonate in the LDH. The suggested anions may be urea, carbamate, cyanate and/or isocyanate, and carbonate species. The capture of CO2 from the natural gas stream using the synthesized Mg-Al LDH has been performed using dynamic flow system at temperature of 30 °C under atmospheric pressure. The results revealed that the intercalation of nitrogen-containing anions in the LDH structure greatly enhances the adsorption activities for CO2 even at low aluminum content. Under the experimental conditions, the maximum adsorption capacity is 5.07 mmol/g for Mg-Al LDH having 5% Al content and synthesized at 80 °C.