Al-pillared montmorillonite clay minerals: Low-pressure CO adsorption at room temperature

Three kinds of Al-pillared montmorillonite clay minerals (AlPMON) ion-exchanged with cobalt(II), nickel(II), or copper(II) ions were prepared (abbreviated as CoAlPMON, NiAlPMON, or CuAlPMON, respectively). For the 673-K- and 873-K-treated samples, carbon monoxide (CO) adsorption measurement was performed at room temperature under an atmosphere of low CO pressure. The 873-K-treated CuAlPMON sample exhibited more efficient adsorption properties for CO molecules, in comparison with both-temperatures-treated CoAlPMON and NiAlPMON samples and the 673-K-treated CuAlPMON sample. In addition, irreversibly adsorbed CO was present only on the CuAlPMON sample that had been treated at 873 K; the sites responsible for strong CO adsorption were formed in the sample after the pretreatment at the higher temperature.

Graphical abstractIrreversibly adsorbed CO molecules at room temperature were present only on the copper-ion-exchanged Al-pillared montmorillonite clay mineral that had been treated at a higher temperature in vacuo among the samples presented in this study; the sites responsible for strong CO adsorption were formed in this clay.Figure optionsDownload full-size imageDownload as PowerPoint slide