title: High-temperature adsorption of carbon dioxide on mixed oxides derived from hydrotalcite-like compounds.
abstract: Various XnY(3-n)Al-hydrotalcite-like compounds (HTlcs) were synthesized by the constant pH coprecipitation method with the (X2+ + Y2+)/Al3+ molar ratio fixed at 3.0. Well-mixed oxides Xn,Y(3-n)AlO were derived from corresponding HTlcs precursors upon calcination. Physicochemical characterization with X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and the Brunauer-Emmett-Teller equation indicates that the derived oxides are of either periclase or spinel phase, with an interparticle pore diameter of 9.6-15.4 nm. These oxides generally show a high CO2 adsorption capability at 350 degrees C. For example, CaCoAlO captures 1.39 mmol/g of CO2 (i.e., 6.12 wt %) from a gas mixture (8% CO2 in N2) at 350 degrees C and 1 atm in a fixed-bed reactor within 20 min. All other mixed oxides adsorb 0.87-1.28 mmol/g (3.83-5.63 wt %) of CO2. Therefore, these mixed oxides are potential cost-effective CO2 sorbents for environmental remediation. In addition, the CO2 adsorption behavior is well-described with the deactivation model. The species of CO2 formed on the sorbents are various carbonates, as revealed by in situ IR spectra as well as TGA.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors.forename: Xiao Ping
authors.initials: XP
authors.lastname: Wang
authors.forename: Jun Jie
authors.initials: JJ
authors.lastname: Yu
authors.forename: Jie
authors.initials: J
authors.lastname: Cheng
authors.forename: Zheng Ping
authors.initials: ZP
authors.lastname: Hao
authors.forename: Zhi Ping
authors.initials: ZP
authors.lastname: Xu
mesh_terms: D000327:Adsorption; D000393:Air Pollutants / Q000737:chemistry*; D000397:Air Pollution / Q000517:prevention & control; D000536:Aluminum Hydroxide; D002245:Carbon Dioxide / Q000737:chemistry*; D006358:Hot Temperature; D008276:Magnesium Hydroxide; D010087:Oxides / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D010087:Oxides; D002245:Carbon Dioxide; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D008276:Magnesium Hydroxide