Synthesis of Zn–Al LDHs intercalated with urea derived anions for capturing carbon dioxide from natural gas

Abstract Zinc–aluminum layered double hydroxides (Zn–Al LDHs) with different Zn/Al ratios (Zn/Al = 6, 3 and 2) were prepared using a homogenous precipitation method by urea hydrolysis. The preparation was performed at various temperatures (70–100 °C). The element chemical analysis, X-ray powder diffraction and Fourier transform infrared spectra show that urea species and cyanate anions are the main anions intercalated at low temperature and low Zn/Al ratios. This was confirmed by pH curves recorded during the reaction, thermal analyses, temperature programmed desorption. The presence of intercalated urea and cyanate species creates UV absorption activities for the ZA15-80 and ZA35-80 samples and enhance the selectivity of ZA15-80 toward the adsorption of carbon dioxide from natural gas.