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.