FORMATION OF HYDROXY-Al-MONTMORILLONITE COMPLEXES AS INFLUENCED BY CITRIC ACID

Goh, Tee Boon; Huang, P. M.

doi:10.4141/cjss84-042

Cited by 22 publications

(16 citation statements)

References 20 publications

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“…In the genesis of interlayer aluminum hydroxide, anions such as carboxylate (Goh and Huang, 1984) or phosphate (Kodama and Webber, 1975) may partly replace the hydroxyls and thus occur between the layers (Violante and Huang, 1985). Hydroxy-Al polycations, however, are bound strongly to montmorillonite at pH of about 5, and are inaccessible to citrate.…”

Section: Discussionmentioning

confidence: 99%

“…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%

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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: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interactions of Citric Acid and Synthetic Hydroxy-Aluminum Montmorillonite

Cambier

Sposito

1991

Clays and clay miner.

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“…Kwong and Huang (1981) demonstrated that differences in the properties of the hydrolytic products orAl formed in the presence of low-molecular-weight orgarlic acids (e.g., citric acid) and high-molecular-weight polyphenolic organic acids (e.g., tannic acid) are attributable to the differences in the chemical as well as the physical behavior of the organic acids. Goh and Huang (1984) reported that the citric acid/Al molar ratio significantly influenced the degree to which citric acid perturbed the formation of hydroxy-Al-montmorillonite complexes at the A1/clay ratio of 600 meq AP+/100 g. They further noted that a citrate/Al molar ratio of 0.5 was apparently critical in perturbing the formation of the hydroxy-Al-montmorillonite complexes. The differences in the mechanism by which citric and tannic acids would influence the formation ofhydroxy-Al-montmorillonite was, however, not discussed.…”

Section: Introductionmentioning

confidence: 97%

“…In suppressing the hydrolysis of the A1 a+, the citrate ligands reduced the growth of the hydroxy-A1 polymers and, hence, their net positive charge. Furthermore, the structural distortion in the interlayer sheet (see Goh and Huang, 1984) reduced the tenacity with which the hydroxy-Al-citrate polymers were held. Thus, the proportion of the adsorbed A1 that was exchanged by 1 M KC1 increased as the citrate/A1 ratio increased to 1.0.…”

Section: Exchangeability and Extractability Of Al Removed From Solutionmentioning

confidence: 99%

Influence of Citric and Tannic Acids on Hydroxy-Al Interlayering in Montmorillonite

Goh

1986

Clays and clay miner.

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Abstract--The formation ofhydroxy-Al-interlayered montmorillonite was affected by complexing organic acids. Montmorillonite (<2.0 t~m) was aged for three months at an initial pH of 5.0 or 6.0 in A1C13 solutions containing citric or tannic acid at organic acid/A1 molar ratios from 0 to 1.0. The A1/clay ratio in the system was 900 meq AP+/100 g of montmorillonite. Ion-exchange experiments revealed that organically complexed A1 ions have both positive and negative charges. Evidence from X-ray powder diffraction, electron microscopic examination, measurements of specific surface, cation-exchange capacity, organic carbon, and the nature of sorbed A1 indicates that citric and tannic acids influence differently the hydroxy-A1 interlayer formation in montmorillonite. Hydroxy-Al-citrate can be adsorbed as interlayers in montmorillonite, but hydroxy-Al-tannate exists principally as a separate phase binding the clay particles. The differences observed between the influence of citric and tannic acids on AI interlayering are probably due to their differences in molecular weight (size) and structure.

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“…There are many reports in the literature on the concern on the characteristics of such systems as mineralorganic substance-aluminum, iron, and other ion salts (Bruggenwert et al Huang, 1984;Keren, 1986;Violante et al, 1999;Yariv & Cross, 2002). There are, however, few of them concerned with the issue here discussed, i.e.…”

Section: Introductionmentioning

confidence: 63%

Electrolytic conductivity of synthetic organomineral complexes

Ksiezopolska

2005

Sci. agric. (Piracicaba, Braz.)

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The mechanism of the formation of organomineral complexes in soils is very complex and still little known. Examination of the complexes in unaltered form, as isolated from the soil, is very difficult due to the dispersing effect of all extraction agents which break the complexes up, destroying their natural properties. It is much easier to perform most of the tests on preparations of organomineral complexes obtained under laboratory conditions. This paper is concerned with model research on the formation of synthetic complexes of humic acids with minerals: Na-montmorillonite, mica, kaolinite at various pH values (3-7) and in the presence of aluminum ions. The aim of the research was to develop an optimum reaction of suspension for the synthesis of organomineral complexes, to study the role of aluminum ions, and to attempt to determine the degree of their complexity on the basis of the electrolytic conductivity (EC). An important influence of the suspension pH value on the value of EC was observed. The greatest correlation was found in the organomineral preparations with kaolinite and with aluminum (r = 0.93 *** ). Generally, it can be stated that the degree of reaction of humic acids with minerals depended most of all on the type of mineral, on the pH value, and on the presence of aluminum.

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FORMATION OF HYDROXY-Al-MONTMORILLONITE COMPLEXES AS INFLUENCED BY CITRIC ACID

Cited by 22 publications

References 20 publications

Interactions of Citric Acid and Synthetic Hydroxy-Aluminum Montmorillonite

Interactions of Citric Acid and Synthetic Hydroxy-Aluminum Montmorillonite

Influence of Citric and Tannic Acids on Hydroxy-Al Interlayering in Montmorillonite

Electrolytic conductivity of synthetic organomineral complexes

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