Activity of Aluminum Hydroxy Sulfate and the Stability of Hydroxy Aluminum Interlayers in Montmorillonite

Singh, Sneha; Brydon, J. E.

doi:10.4141/cjss70-030

Cited by 18 publications

(4 citation statements)

References 7 publications

(14 reference statements)

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“…In particular, the structure of the interlayer hydroxy-Al polymers (Hsu, 1968;Veith, 1977;Lahav et aL, 1978;Plee et al, 1985) and their adsorption reactions with anions (Webber and Clark, 1969;Singh and Brydon, 1970;Keren and Gast, 1983;Goh and Huang, 1984;Harsh and Doner, 1985) have been examined in relation to anion solubility (Traina et aL, 1987) or AI toxicity (Goh et al, 1986). Huang and Violante (1986) summarized research on the influence Copyright 9 1991, The Clay Minerals Society of organic acids on the genesis of hydroxy-A1 montmorillonite under conditions similar to those in acidic surface soils that contain significant amounts of labile organic matter.…”

Section: Introductionmentioning

confidence: 99%

Interactions of Citric Acid and Synthetic Hydroxy-Aluminum Montmorillonite

Cambier

Sposito

1991

Clays and clay miner.

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Abstract--Hydroxy-Al-montmorillonite was prepared by mixing Na-Wyoming montmorillonite with AI(OH)z5 polycations and aging the mixture for 10 days. The reactions of this complex with citric acid at millimolar concentrations were investigated at different pHs for a 4-hr reaction time. The citrate sorption data, X-ray powder diffraction patterns of the montmorillonite adsorbent, and solubility products for AI(OH)3, estimated after computer speciation of the aqueous solution phase, suggested two reaction mechanisms, depending on pH. At 4 < pH < 5.5, the complex was stable, and only external hydroxy-A1 polycations could react with citrate, yielding a sorption envelope characteristic of an acid having a low pI~. At higher pH, and particularly at pH > 7, the interlayer Al-polymers became accessible to the ligand and desorbed quickly from the montmorillonite basal planes to form a new, external, X-rayamorphous solid phase with citrate. This reaction produced a large second peak in the sorption envelopes near pH 8, which was controlled by the increasingly negative surface charge at high pH and by the initial concentration of citric acid. This ligand accelerated, i.e., favored kinetically, the dissociation of adsorbed hydroxy-Al polymers from moutmorillonite at pH > 7.Key Words--Adsorption, Citric acid, Hydroxy-Al, Montmorillonite, X-ray powder diffraction.R6sum6--On pr6pare une smectite hydroxyalumineuse en m61angeant et en laissam en suspension 10 jours une montmorillonite du Wyoming Na et des polycations AI(OH)2 5. Les r6actions de ce complexe avec racide citrique en concentration millimolaire et~ different pH sont analys6es ~ partir des quantit~s de citrate adsorb6, de la diffraction X appliqu~e ~t des d~pbts orient6s de l'arglle ayant r~agi, du calcul du produit de solubilit6 AI(OH)~ et des concentrations des diverses esp~ces en solution. Deux m6canismes sont invoqu6s selon les domaines de pH. A 4 < pH < 5.5, le complexe est stable et seuls les polym6res d'Al des surfaces extemes peuvent r6agir avec le citrate, conduisant ~t une fixation de citrate faible, caract6ris6e par des courbes en fonction du pH avec un maximum apparent. A pH plus 61ev~ et surtout pH > 7, tousles polym~res d'A1 deviennent accessibles au ligand, et sont rapidement d~tach~s des surfaces basales pour former avec le citrate une nouvelle phase amorphe en dehors des feuillets de l'argile. Cette derni~re r~action se traduit par un deuxi~me maximum plus important darts les courbes enveloppes, vers pH 8, dont l'amplitude est limit~e par l'effet de l'augmentation des charges n6gatives ~ pH 61ev6, et par la quantit~ initiale de citrate. Cet anion acc61~re la dissociation des polym~res d'A1 et de la montmorillonite/l pH > 7.

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Section: Introductionmentioning

confidence: 99%

Interactions of Citric Acid and Synthetic Hydroxy-Aluminum Montmorillonite

Cambier

Sposito

1991

Clays and clay miner.

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“…Investigations of white aluminous precipitates in acid mine waters indicate that this material can be approximated most closely by either amorphous to crystalline aluminum hydroxide [Al(OH) 3 ] or amorphous basaluminite [Al 4 (OH) 10 SO 4 ] (Singh, 1969;Singh and Brydon, 1970;Adams and Rawajfih, 1977;Nordstrom, 1982;Nordstrom and others, 1984). The following two reactions were used to define the precipitating phases for the OTEQ simulations:…”

Section: Thermodynamic Datamentioning

confidence: 99%

Questa baseline and pre-mining ground-water quality investigation. 12. Geochemical and reactive-transport modeling based on tracer injection-synoptic sampling studies for the Red River, New Mexico, 2001-2002

Ball¹,

Runkel²,

Nordstrom³

2005

Scientific Investigations Report

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“…In experiments with a mixecl sc, + cl system, Singh and Brydon (1970) ' Oriented-aggregate specimens for X-ray diffraction analyses were prepared by washing the solids once with water, and then drying the aliquots (1 ml) of suspensions c6ntaining about 20 mg of solids on 37. There is a net deflcit o!…”

Section: Ii{troductionmentioning

confidence: 99%