High-temperature adsorption of carbon dioxide on mixed oxides derived from hydrotalcite-like compounds.
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.
Wang
Xiao Ping
XP
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
Yu
Jun Jie
JJ
Cheng
Jie
J
Hao
Zheng Ping
ZP
Xu
Zhi Ping
ZP
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*
D000393:Air Pollutants; D010087:Oxides; D002245:Carbon Dioxide; C010467:hydrotalcite; D000536:Aluminum Hydroxide; D008276:Magnesium Hydroxide