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Abstract: In this paper, diamine modified montmorillonite was prepared by water aided exfoliation/grafting method. The materials were characterized by elemental analysis (EA), X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectrometer (DRIFTS), automated surface area and porosity analyser (ASAP 2420) and thermogravimetric analysis (TGA). Adsorption of carbon dioxide on modified montmorillonite was investigated by isothermal CO2 adsorption, temperature ramp CO2 adsorption, regeneration screening test with adsorption/desorption cycles, and multiple cyclic test. The maximum adsorption capacity for modified montmorillonite is 2.4mmolg−1 at 100°C. In a 15% CO2 in N2 mixture, the material achieves a maximum adsorption capacity of 1.8mmolg−1, which is 75% of its maximum capacity in pure CO2. The optimum adsorption and desorption temperature are found to be 80 and 160°C, respectively, by regeneration testing. The long term performance was also studied in pure CO2, 15% CO2 in N2 and 15% CO2 in N2 with 1000ppm SO2. The material is stable in pure CO2 and 15% CO2 in N2, while the adsorption capacity drops dramatically with the presence of SO2. In order to understand the kinetics of CO2 adsorption, four kinetics models were evaluated, with the Avrami equation providing the best experimental-simulation fit. [Copyright &y& Elsevier]

Abstract: 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 1.39mmolg−1 and the amine efficiency was about 0.4. The model derived from carbamate formation mechanism showed good agreement with the experimental data. [Copyright &y& Elsevier]