Adsorption of Water by Homoionic Exchange Forms of Wyoming Montmorillonite (SWy-1)

Hall, Peter G.

doi:10.1346/ccmn.1989.0370409

Cited by 51 publications

(40 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Water loss varied depending on the interlayer cation, producing a trend of increasing water content as follows: Na + < Fe 3+ < Ca 2+ < Mg 2+. This is comparable to adsorption isotherm trends observed for Na § and Ca 2 § montmorillonites (Hall and Astill 1989) and for Na § Ca 2+ and Mg 2 § hectorites , where the amount of water absorbed by a given smectite varies with the type of interlayer cation and the relative humidity.…”

Section: Thermal Gravimetric Analysessupporting

confidence: 85%

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Bishop

Pieters

Edwards

1994

Clays and clay miner.

382

256

View full text Add to dashboard Cite

Abstract--Interlayer cations and moisture content greatly influence the molecular vibrations of H20 in montmoriUonite as shown through reflectance spectroscopy in the infrared. The absorptions due to H~O have been studied in montmorillonites exchanged with H, Na, Ca, Mg and Fe 3+ interlayer cations under variable moisture environments. Band assignments have been made for absorptions in the 3 ~tm region due to structural OH vibrations, symmetric and asymmetric 1-120 stretching vibrations and the H20 bending overtone. Changes in the energies of the absorptions due to H20 stretching vibrations were observed as the samples were dehydrated by reducing the atmospheric pressure. Absorptions near 3620 cm -1 and 3550 cm -1 have been assigned to water bound directly to cations (inner sphere) and surfacebonded H20 and absorptions near 3450 cm -1 and 3350 cm ~ have been assigned to additional adsorbed water molecules. Band assignments have been made for combination bands in the near-infrared as well. Absorptions near 1.41 ~m and 1.91/zm are assigned to bound H20 combination bands, while the shoulders near 1.46 izm and 1.97 ~*m are assigned to combinations of additional H20 molecules adsorbed in the interlayer regions and along grain surfaces.

show abstract

Section: Thermal Gravimetric Analysessupporting

confidence: 85%

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Bishop

Pieters

Edwards

1994

Clays and clay miner.

382

256

View full text Add to dashboard Cite

show abstract

“…Recently, Hall and Astill (1989) reported adsorption isotherms for water on SWy-1 montmorillonite exchanged with Ca, Li, Na, and K that show that considerably more water is present in the desorption isotherm at a given P/Po than in the adsorption isotherm (i.e., hysteresis). A similar result was reported long ago by Mooney et al (1952a), who showed that desorption isotherms were reproducible, but adsorption isotherms depended strongly on the initial water content and were, in general, not reproducible.…”

Section: Discussionmentioning

confidence: 99%

“…When less than three molecular layers of water are present in the interlamellar region, the structure of sorbed water on smectites has been shown to be influenced predominantly by exchangeable cations (Mooney et al, 1952b;Clementz et al, 1973Clementz et al, , 1974Prost, 1975;McBride, 1982;Sposito and Prost, 1982;Sposito et al, 1983;Bidadi et al, 1988;Grandjean and Laszlo, 1989;Kogelbauer et al, 1989;Hall and Astill, 1989;Trillo et aL, 1990;Fu et aL, 1990;Delville et aL, 1991;Tinet et al, 1992). Spectroscopic investigations of smectite-water interactions (Prost, 1975;Sposito and Prost, 1982;Brown and Kevan, 1988;Weiss et al, 1990a;Bank et al, 1991;Tinet et al, 1992) suggest that two distinct environments of sorbed water are present: 1) water molecules coordinated directly to exchangeable metal cations, and 2) physisorbed water molecules occupying interstitial pores, interlameUar spaces between exchangeable metal cations, or polar sites on external surfaces.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Probe Studies of Water Interactions with Montmorillonite

Johnston

Sposito

Erickson

1992

Clays and clay miner.

122

114

View full text Add to dashboard Cite

Abstract--Imeraction of water with montmorillonite exchanged with Na +, K +, Co 2+, and Cu 2+ cations as a function of water content was examined using an FTIR/gravimetric cell designed to collect spectroscopic and sorption data simultaneously. Correlation of water desorption isotherms with infrared spectra of the clay-water complex showed that the position of the HOH bending band of water decreased as a function of water content. The largest decreases in frequency were observed for Cu 2+ and Co 2 +; smaller decreases were found for Na + and K + . In addition, the molar absorptivity of sorbed water increased upon decreasing the water content. The decrease in frequency and the concomitant increase in molar absorptivity were attributed to polarization effects on the sorbed water molecules by exchangeable cations. The interference fringes of a self supporting clay film permitted d-spacings to be determined optically and, therefore, changes in frequency, molar absorptivity, and water sorption behavior to be related directly to changes in interlayer spacing. The d-spacings obtained from the interference fringes were consistently larger by approximately 0.5 ~ than those determined using powder XRD.

show abstract

“…The exchangeable cation abundance is characterized by the cation exchange capacity, which in total is 81 meq L-• for SWy-1. The breakdown by species is 48 meq Na+; 1.1 K+; 12 Mg2+; 21 Ca 2+ [Hall and Astill, 1989].…”

Section: Methodsmentioning

confidence: 99%

H₂O adsorption on smectites: Application to the diurnal variation of H₂O in the Martian atmosphere

Zent¹,

Howard²,

Quinn³

2001

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. Observations of the Martian planetary boundary layer lead to interpretations that are baffling and contradictory. In this paper we specifically address the question of whether or not water vapor finds a substantial diurnal reservoir in the Martian regolith. To address this issue, we have measured H20 adsorption kinetics on SWy-1, a Na-rich montmorillonite from Wyoming. The highest-temperature (273 K) data equilibrate rapidly. Data gathered at realistic H20 partial pressures and temperatures appropriate to early morning show two phenomena that preclude a significant role for smectites in diurnally exchanging a large column abundance. First, the equilibration timescale is longer than a sol. Second, the equilibrium abundances are a small fraction of that predicted by earlier adsorption isotherms. The explanation for this phenomenon is that smectite clay actually increases its surface area as a function of adsorptive coverage. At Mars-like conditions we show that the interlayer sites of smectites are likely to be unavailable. Introduction Martian Boundary Layer Is PuzzlingObservations of the Martian planetary boundary layer, although incomplete and difficult to reduce, lead to interpretations that are baffling and contradictory. In this paper we specifically address the question of whether or not water vapor finds a substantial diurnally exchangeable reservoir in the Martian regolith. The planetary boundary layer (PBL) is the lowest section of the atmosphere, which is diurnally affected by substantial momentum transfer from the heated planetary surface. Observations disagree on whether or not the total atmospheric column abundance of H20 varies significantly at a specific location as a function of hour angle. Some observations, chiefly from ground-based telescopes and from the infrared mapping spectrometer (ISM) instrument on Phobos, indicate a tremendous variation over the course of the day. Other observations, specifically, those from Pathfinder and the Viking Orbiters, are most conveniently interpreted to indicate no measurable diurnal variations in the H20 column abundance. Numerical models of the PBL, coupled with an adsorbing material on the Martian regolith, have been developed and exercised in a variety of configurations. They are uniformly unable to predict observable diurnal variations in atmospheric H20 abundance when constrained with independent variables that are most compatible with observations. That said, there are clearly ways in which models can be forced to predict substantial diurnal exchange, although this comes at the cost of violating observational constraints. The simplest technique for forcing substantial exchange is to posit that the Martian surface is locally covered with a highly adsorbing smectite clay. These clays have a much larger adsorptive capacity than ordinary particulates comprising regolith One important assumption must be made, however, in order to force PBL models to predict observable diurnal H20 exchange with smectite clays: the clays must equilibrate with the surr...

show abstract

Adsorption of Water by Homoionic Exchange Forms of Wyoming Montmorillonite (SWy-1)

Cited by 51 publications

References 30 publications

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Vibrational Probe Studies of Water Interactions with Montmorillonite

H₂O adsorption on smectites: Application to the diurnal variation of H₂O in the Martian atmosphere

Contact Info

Product

Resources

About

Adsorption of Water by Homoionic Exchange Forms of Wyoming Montmorillonite (SWy-1)

Cited by 51 publications

References 30 publications

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Infrared Spectroscopic Analyses on the Nature of Water in Montmorillonite

Vibrational Probe Studies of Water Interactions with Montmorillonite

H2O adsorption on smectites: Application to the diurnal variation of H2O in the Martian atmosphere

Contact Info

Product

Resources

About

H₂O adsorption on smectites: Application to the diurnal variation of H₂O in the Martian atmosphere