Selective adsorption of CO on CuCl/Y adsorbent prepared using CuCl2 as precursor: Equilibrium and thermodynamics

Abstract

Zeolite Y supported CuCl (CuCl/Y) has been prepared with CuCl2 as precursor by a monolayer dispersion method, followed by activation with CO. The samples are investigated for CO adsorption and characterized by inductively coupled plasma optical emission spectrometry, X-ray diffraction, N2 adsorption/desorption and X-ray photoelectron spectroscopy. The characterization results reveal that CuCl2 supported on zeolite Y can be completely reduced to CuCl after activation at 663K in CO, and the monolayer dispersion capacity of CuCl on zeolite Y support is 5mmol/g zeolite Y. The resulting adsorbent displays high CO adsorption capacity, high CO/N2, CO/CH4 and CO/CO2 adsorption selectivities, and excellent reversibility and regenerability. The adsorption equilibrium isotherms of CO on the adsorbents at temperatures up to 333K can be well fitted by both the Langmuir and Sips models, and the integral thermodynamic data of Gibbs’ energy change (ΔG), entropy change (ΔS) and enthalpy change (ΔH) are calculated from the fitted Langmuir adsorption equations. The negative ΔG and ΔH values indicate that the adsorption process of CO on CuCl/Y adsorbent is spontaneous and exothermic. The negative ΔS value indicates that the adsorbed CO molecules on the adsorbent are in an ordered arrangement.