In this study, layered double hydroxide [M^II-Al LDH (M^II = Mg/Zn)] were used as selective CO₂ adsorbents from methane stream. It prepared by microwave (MW) assisted homogenous precipitations via urea hydrolysis. The LDH structures and the type of intercalated anions were confirmed by the X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermal analysis (DSC and TGA), and elemental analysis, and scanning and transmission electron microscopes (SEM and TEM) imaging. The results indicated that; the LDH morphology and the intercalated anions (carbonate and urea species) were dependent on MW power, time, and M^II type. The predominant urea species were carbamate and isocyanate for Mg-Al LDH and Zn-Al LDH, respectively. The efficiencies of the LDH were tested towards CO₂ capture from methane stream using dynamic flow system under atmospheric pressure. Effect of temperature and adsorption/desorption cycles were studied. The best CO₂ adsorption capacities obtained at (30 °C) were 3.25, and 2.47 mmol g⁻¹ for Mg-Al-LDH and Zn-Al LDH, respectively. Whereas, those for the calcined LDH (at 550 °C) were 2.96 and 2.29 mmol g⁻¹ for Mg-Al-LDO and Zn-Al LDO, respectively. The results revealed the role of the intercalated urea derived anions type in enhancing the LDH adsorption properties to selectively capture CO₂ from methane stream.

在这项研究中，层状双氢氧化物 [M ^II -Al LDH (M ^II  = Mg/Zn)] 被用作甲烷流中的选择性 CO ₂吸附剂。它通过微波 (MW) 辅助尿素水解均相沉淀制备。通过 X 射线衍射 (XRD)、傅里叶变换红外 (FTIR)、热分析 (DSC 和 TGA)、元素分析以及扫描和透射电子显微镜 (SEM 和 TEM) 证实了 LDH 结构和嵌入阴离子的类型) 成像。结果表明；LDH 形态和嵌入的阴离子（碳酸盐和尿素种类）取决于 MW 功率、时间和 M ^II类型。对于 Mg-Al LDH 和 Zn-Al LDH，主要的尿素种类分别是氨基甲酸酯和异氰酸酯。在大气压下使用动态流动系统测试了 LDH 对从甲烷流中捕获CO ₂的效率。研究了温度和吸附/解吸循环的影响。在 (30 °C) 下获得的最佳 CO ₂吸附容量分别为 3.25 和 2.47 mmol g ^-1 Mg-Al-LDH 和 Zn-Al LDH。而对于 Mg-Al-LDO 和 Zn-Al LDO，煅烧 LDH（在 550°C）的那些分别为 2.96 和 2.29 mmol g ^-1。结果揭示了插层尿素衍生阴离子类型在增强 LDH 吸附性能以选择性捕获 CO _{2 中的作用} 来自甲烷流。