Structural Effects and Interactions of Carbon Dioxide Molecules Adsorbed on Ni, Zn, and Cd Nitroprussides
- Univ. of Turabo, Gurabo (Puerto Rico). Inst. for Physical Chemical Applied Research
- Univ. of Puerto Rico, Mayaguez (Puerto Rico). Engineering Science and Materials Dept.
- Univ. of Puerto Rico, Mayaguez (Puerto Rico). Dept. of Chemical Engineering
- Univ. of Puerto Rico, Mayaguez (Puerto Rico). Chemistry Dept.
A thorough structural characterization of the synthesized Ni-, Zn-, and Cd-nitroprussides (NPs) with X-ray diffraction (XRD), thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectrometry (DRIFTS), M€ossbauer spectroscopy, and magnetic measurements was performed. We studied the innovative part of the research for the structural effects and the interactions of the CO2 molecule with the Ni-, Zn-, Cd-NP frameworks. DRIFTS of adsorbed molecules, high pressure adsorption, and in situ XRD adsorption experiments were performed. The DRIFTS spectra displayed peaks assigned to CO2 physical adsorption and the formation of adducts (M2+ ∙∙∙ O=C=O). The fitting of the adsorption data to the Dubinin₋Radushkevich equation and a Langmuir-type equation for volume filling allowed the calculation of the micropore volume and the isosteric heats of adsorption. Furthermore, the calculated parameters indicated an unusual behavior of the adsorption process in Cd-NP at high pressure. This fact was caused by the interaction of CO2 molecules with the framework cations and the small adsorption space of Cd-NP. The Ni- and Zn-NPs behaved normally. The Pawley fitting of the XRD profiles of the dehydrated materials and under CO2 adsorption indicated that in both cases Ni-NP, Zn-NP, and Cd-NPs displayed the Fm$$\overline{3}$$m, R$$\overline{3}$$, and Pnma space groups, respectively. The dehydrated samples demonstrated a change in the cell parameters. But, only Cd-NP presented a noticeable variation of its cell parameters under CO2 adsorption. This fact was linked to the unusual behavior of the adsorption process in Cd-NP. In addition, we show that dehydrated Ni-, Zn-, and Cd-NPs can store 27, 22, and 15 wt % of CO2 at 298 K and 9 atm., respectively. Then, Ni- and Cd-NPs are excellent for CO2 storage, and Cd-NP is good for gas cleaning.
- Research Organization:
- Univ. of Turabo, Gurabo (Puerto Rico)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF)
- DOE Contract Number:
- NA0000672; CHE-0959334
- OSTI ID:
- 1336257
- Journal Information:
- Journal of Physical Chemistry. C, Vol. 115, Issue 31; ISSN 1932-7447
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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