Preparation and CO₂ adsorption of amine modified layered double hydroxide via anionic surfactant-mediated route

Amine modified layered double hydroxides were prepared via an anionic surfactant-mediated route followed by monoethanolamine (MEA) extraction. The as-prepared materials were characterized by elemental analysis, X-ray diffraction, thermogravimetric analysis and diffuse reflection infrared Fourier transform spectroscopy. CO₂ adsorption was performed in a TG 209 F1 thermogravimetric analyzer. The results showed that amine modified layered double hydroxides were successfully prepared via the anionic surfactant-mediated route but a considerable amount of amino groups were protonated which hindered CO₂ adsorption. After MEA extraction, the materials were exfoliated and lost their layered structure. Free amino groups were obtained through the ionic exchange between protonated amine group and ethanolamine. The CO₂ adsorption capacity at 25 °C reached 1.39 mmol g⁻¹ and the amine efficiency was about 0.4. The model derived from carbamate formation mechanism showed good agreement with the experimental data.