Adsorption of water and methanol by organic complexes of montmorillonites

Slabaugh, W. H.; Kennedy, George H.

doi:10.1016/0095-8522(63)90024-2

Cited by 12 publications

(2 citation statements)

References 6 publications

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“…With increasing delamination (decreasing n) the external free surface afe and the total free surface af~afi + afe increase, and the internal free surface afi decreases (Table 4). The heat of immersion AW H is split into terms for wetting of the internal (Aw^) and external surfaces (Awi / e) ： Aw/ / = A w^ + Awi / e (J/g) (15) Adsorption occurs on the free internal and external surfaces (Slabaugh & Kennedy, 1963): AW H = afi. Awht + afe.…”

Section: Discussionmentioning

confidence: 99%

Short-Chain alkylammonium montmorillonites and alcohols: gas adsorption and immersional wetting

Malberg

Dékány²,

Lagaly

1989

Clay miner.

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A B S T R A C T :Short-chain alkylammonium derivatives of montmorillonite ( < 8 or 10 C atoms in the alkyl chain) adsorb alcohols in the micropores between the alkylammonium ions. The external surface area and the micropore volume are derived from comparison plots of ethanol and butanol adsorption isotherms. The micropore volume varies between ~ 0 (decylammonium derivative) and 100/~l/g (methylammonium derivative); the external surface area determined by ethanol and butanol gas adsorption is about 50 m2/g, and is almost independent of the alkyl chain length. In contact with the alcohols, the alkylammonium ions in the interlayer space remain in h 1 or h2 arrangement (monolayers or bilayers of fiat-lying alkylammonium ions); on the external surface they move into an upward position. The heat of immersion decreases strongly with increasing alkyl chain length to a minimum for decylammonium ions, the variation being very similar for ethanol, butanol, hexanol, octanol and decanol. Immersion in ethanol increases the external surface area at the expense of the internal surface area. In butanol and longer alcohols this area remains unchanged. The increase of the external surface is related mainly to changes in the less ordered regions around the core of the crystals which consists of coherent silicate layers. The heat of wetting is ~ 110 mJ/m 2 (external and internal surfaces). The integral enthalpy of adsorption of butanol, 40-50 kJ/mol, is independent of the alkyl chain length (nr < 8).Montmorillonites with n-alkylammonium ions between the layers adsorb primary alcohols under formation of bimolecular structures. InterlameUar films consisting of long-chain alkylammonium ions and alkanol molecules are well known models for studying temperature-induced alkyl chain conformations and phase transitions (Lagaly, 1976(Lagaly, , 1981. However, interlamellar adsorption is accompanied by an expansion of the interlamellar distance (basal spacing) only when the alkylammonium ions are sufficiently long. Shortchain alkylammonium derivatives (with the exception of the methyl ammonium derivative) adsorb the alkanols without, or with modest (< 0-03 nm), changes in the basal spacing (Fig.

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Section: Discussionmentioning

confidence: 99%

Short-Chain alkylammonium montmorillonites and alcohols: gas adsorption and immersional wetting

Malberg

Dékány²,

Lagaly

1989

Clay miner.

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“…41 In other words, MMT nanoparticles because of their high surface area and cation exchange capacity absorb H + in the aqueous media in order to minimize their surface energy which causes the expansion of chitosan networks to be decreased. [54][55][56] In the case of chitosan/SMMT, the immobilized chitosan sulfate chains on the exfoliated clay nanosheets provide tighter networks with relatively lower water uptake capacity. To simulate the physiological condition, water uptake measurements were also performed using PBS solution (pH ¼ 7.4).…”

Section: Water Uptakementioning

confidence: 99%