Calorimetric and spectroscopic studies of water adsorption onto alkaline earth fluorides

Toshinori Mori, Yasushige Kuroda, Ryotaro Kumashiro, Koji Hirata, Hidehiro Toyota, Mahiko Nagao

Research output: Contribution to journalArticle

Abstract

Interactions between the surfaces of alkaline earth fluorides (CaF2, SrF2 and BaF2) and water molecules were investigated by calorimetric and spectroscopic methods. The exposed surfaces of the alkaline earth fluoride samples, with which the (100) crystalline plane is mainly associated, were found to be fully covered with strongly adsorbed water molecules, resulting in characteristic IR bands at 3684, 2561, 1947 and 1000 cm-1, respectively. This surface was homogeneous towards further water adsorption. The strongly adsorbed water molecules were almost completely desorbed from the surface on evacuating the sample up to 473 K. The heat of immersion in water also increased with increasing pretre atment temperature; this may be attributed to surface rehydration of the alkaline earth fluorides. The state of the surface changed drastically as the pretreatment temperature was increased and stabilized towards incoming water molecules. Thus, the surface formed after evacuation at temperatures greater than 473 K was resistant to hydration even after immersion in water at room temperature. This surface was relatively heterogeneous towards water adsorption, although it behaved homogeneously towards argon adsorption. These facts indicate that strongly adsorbed water molecules appear to be somewhat specific towards the adsorption of further incoming water molecules. The adsorption properties of the (100) plane of alkaline earth fluorides towards water and argon molecules depend strongly on both the electrostatic field strength and the extent of rehydration of the alkaline earth fluoride surface.

Original languageEnglish
Pages (from-to)425-436
Number of pages12
JournalAdsorption Science and Technology
Volume23
Issue number6
DOIs
Publication statusPublished - 2005

Fingerprint

Fluorides
fluorides
Earth (planet)
Adsorption
adsorption
Water
water
Molecules
molecules
Argon
submerging
evacuating
argon
Temperature
Hydration
pretreatment
temperature
hydration
field strength
Electric fields

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Process Chemistry and Technology
  • Physical and Theoretical Chemistry
  • Chemical Engineering(all)

Cite this

Calorimetric and spectroscopic studies of water adsorption onto alkaline earth fluorides. / Mori, Toshinori; Kuroda, Yasushige; Kumashiro, Ryotaro; Hirata, Koji; Toyota, Hidehiro; Nagao, Mahiko.

In: Adsorption Science and Technology, Vol. 23, No. 6, 2005, p. 425-436.

Research output: Contribution to journalArticle

Mori, Toshinori ; Kuroda, Yasushige ; Kumashiro, Ryotaro ; Hirata, Koji ; Toyota, Hidehiro ; Nagao, Mahiko. / Calorimetric and spectroscopic studies of water adsorption onto alkaline earth fluorides. In: Adsorption Science and Technology. 2005 ; Vol. 23, No. 6. pp. 425-436.
@article{1bdf998eec9c4155a90811352099fd16,
title = "Calorimetric and spectroscopic studies of water adsorption onto alkaline earth fluorides",
abstract = "Interactions between the surfaces of alkaline earth fluorides (CaF2, SrF2 and BaF2) and water molecules were investigated by calorimetric and spectroscopic methods. The exposed surfaces of the alkaline earth fluoride samples, with which the (100) crystalline plane is mainly associated, were found to be fully covered with strongly adsorbed water molecules, resulting in characteristic IR bands at 3684, 2561, 1947 and 1000 cm-1, respectively. This surface was homogeneous towards further water adsorption. The strongly adsorbed water molecules were almost completely desorbed from the surface on evacuating the sample up to 473 K. The heat of immersion in water also increased with increasing pretre atment temperature; this may be attributed to surface rehydration of the alkaline earth fluorides. The state of the surface changed drastically as the pretreatment temperature was increased and stabilized towards incoming water molecules. Thus, the surface formed after evacuation at temperatures greater than 473 K was resistant to hydration even after immersion in water at room temperature. This surface was relatively heterogeneous towards water adsorption, although it behaved homogeneously towards argon adsorption. These facts indicate that strongly adsorbed water molecules appear to be somewhat specific towards the adsorption of further incoming water molecules. The adsorption properties of the (100) plane of alkaline earth fluorides towards water and argon molecules depend strongly on both the electrostatic field strength and the extent of rehydration of the alkaline earth fluoride surface.",
author = "Toshinori Mori and Yasushige Kuroda and Ryotaro Kumashiro and Koji Hirata and Hidehiro Toyota and Mahiko Nagao",
year = "2005",
doi = "10.1260/026361705774859910",
language = "English",
volume = "23",
pages = "425--436",
journal = "Adsorption Science and Technology",
issn = "0263-6174",
publisher = "Multi-Science Publishing Co. Ltd",
number = "6",

}

TY - JOUR

T1 - Calorimetric and spectroscopic studies of water adsorption onto alkaline earth fluorides

AU - Mori, Toshinori

AU - Kuroda, Yasushige

AU - Kumashiro, Ryotaro

AU - Hirata, Koji

AU - Toyota, Hidehiro

AU - Nagao, Mahiko

PY - 2005

Y1 - 2005

N2 - Interactions between the surfaces of alkaline earth fluorides (CaF2, SrF2 and BaF2) and water molecules were investigated by calorimetric and spectroscopic methods. The exposed surfaces of the alkaline earth fluoride samples, with which the (100) crystalline plane is mainly associated, were found to be fully covered with strongly adsorbed water molecules, resulting in characteristic IR bands at 3684, 2561, 1947 and 1000 cm-1, respectively. This surface was homogeneous towards further water adsorption. The strongly adsorbed water molecules were almost completely desorbed from the surface on evacuating the sample up to 473 K. The heat of immersion in water also increased with increasing pretre atment temperature; this may be attributed to surface rehydration of the alkaline earth fluorides. The state of the surface changed drastically as the pretreatment temperature was increased and stabilized towards incoming water molecules. Thus, the surface formed after evacuation at temperatures greater than 473 K was resistant to hydration even after immersion in water at room temperature. This surface was relatively heterogeneous towards water adsorption, although it behaved homogeneously towards argon adsorption. These facts indicate that strongly adsorbed water molecules appear to be somewhat specific towards the adsorption of further incoming water molecules. The adsorption properties of the (100) plane of alkaline earth fluorides towards water and argon molecules depend strongly on both the electrostatic field strength and the extent of rehydration of the alkaline earth fluoride surface.

AB - Interactions between the surfaces of alkaline earth fluorides (CaF2, SrF2 and BaF2) and water molecules were investigated by calorimetric and spectroscopic methods. The exposed surfaces of the alkaline earth fluoride samples, with which the (100) crystalline plane is mainly associated, were found to be fully covered with strongly adsorbed water molecules, resulting in characteristic IR bands at 3684, 2561, 1947 and 1000 cm-1, respectively. This surface was homogeneous towards further water adsorption. The strongly adsorbed water molecules were almost completely desorbed from the surface on evacuating the sample up to 473 K. The heat of immersion in water also increased with increasing pretre atment temperature; this may be attributed to surface rehydration of the alkaline earth fluorides. The state of the surface changed drastically as the pretreatment temperature was increased and stabilized towards incoming water molecules. Thus, the surface formed after evacuation at temperatures greater than 473 K was resistant to hydration even after immersion in water at room temperature. This surface was relatively heterogeneous towards water adsorption, although it behaved homogeneously towards argon adsorption. These facts indicate that strongly adsorbed water molecules appear to be somewhat specific towards the adsorption of further incoming water molecules. The adsorption properties of the (100) plane of alkaline earth fluorides towards water and argon molecules depend strongly on both the electrostatic field strength and the extent of rehydration of the alkaline earth fluoride surface.

UR - http://www.scopus.com/inward/record.url?scp=27544463077&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27544463077&partnerID=8YFLogxK

U2 - 10.1260/026361705774859910

DO - 10.1260/026361705774859910

M3 - Article

AN - SCOPUS:27544463077

VL - 23

SP - 425

EP - 436

JO - Adsorption Science and Technology

JF - Adsorption Science and Technology

SN - 0263-6174

IS - 6

ER -