TY - JOUR
T1 - Thermodynamics of H2O and CO2 Absorption and Guest-Induced Phase Transitions in Zeolite RHO
AU - Guo, Xin
AU - Corbin, David R.
AU - Navrotsky, Alexandra
N1 - Funding Information:
We are grateful to Sergey Ushakov and Pinghui Zhang for helpful discussions on absorption measurement. D.R.C. is grateful to Drs. Mark Shiflett, Bill Gilbert, and David Minnick at the Center for Environmentally Beneficial Catalysis at the University of Kansas for their assistance in sample selection. This work was supported by the U.S. Department of Energy grant DE-SC0016573.
Publisher Copyright:
© Copyright 2018 American Chemical Society.
PY - 2018/9/6
Y1 - 2018/9/6
N2 - Gas absorption calorimetry at low pressures has been employed to probe the interaction of water and carbon dioxide with several ion-exchanged zeolite RHO samples. It reveals that guest-induced framework flexibility transitions from a less hydrated (initially anhydrous) acentric form to the more hydrated centric phase during water absorption. The differential enthalpy of absorption as a function of water loading directly identifies the strengths of different interactions along with possible water binding mechanisms. Interactions with CO2 are weaker, and no phase transition is seen except in Li,H-RHO. The most negative initial enthalpies have been obtained in both water and CO2 absorption for Cd and Cs-RHO. However, Li,H-RHO shows the strongest capture ability for CO2 despite a less exothermic initial enthalpy of absorption. The derived differential enthalpy, chemical potential, and entropy elucidate the thermodynamic behavior of multiple interactions of small guest molecules (H2O and CO2) and ion-exchanged flexible zeolite frameworks.
AB - Gas absorption calorimetry at low pressures has been employed to probe the interaction of water and carbon dioxide with several ion-exchanged zeolite RHO samples. It reveals that guest-induced framework flexibility transitions from a less hydrated (initially anhydrous) acentric form to the more hydrated centric phase during water absorption. The differential enthalpy of absorption as a function of water loading directly identifies the strengths of different interactions along with possible water binding mechanisms. Interactions with CO2 are weaker, and no phase transition is seen except in Li,H-RHO. The most negative initial enthalpies have been obtained in both water and CO2 absorption for Cd and Cs-RHO. However, Li,H-RHO shows the strongest capture ability for CO2 despite a less exothermic initial enthalpy of absorption. The derived differential enthalpy, chemical potential, and entropy elucidate the thermodynamic behavior of multiple interactions of small guest molecules (H2O and CO2) and ion-exchanged flexible zeolite frameworks.
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U2 - 10.1021/acs.jpcc.8b06070
DO - 10.1021/acs.jpcc.8b06070
M3 - Article
AN - SCOPUS:85052326264
SN - 1932-7447
VL - 122
SP - 20366
EP - 20376
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 35
ER -