The solution phase complexing of atrazine by fulvic acid: Equilibria at 25°c

Haniff, Mohammed I.; Zienius, Raymond H.; Langford, Cooper H.; Gamble, Donald S.

doi:10.1080/03601238509372477

Cited by 24 publications

(12 citation statements)

References 23 publications

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“…coverage and hence on solution composition (47). Apparently constant values of the atrazine -fulvic acid binding equilibrium function have been observed experimentally however, by Haniff et al (44). A possible reason for this result was that only a small fraction of the carboxyl binding sites was oc_cupied _by atrazine.…”

Section: Sorption Equilibriamentioning

confidence: 69%

“…The experimental evidence for this postulate has been provided by recent investigations of atrazine complexing by fulvic acid (42)(43)(44). The collection of chemically nonidentical carboxyl groups is expected to have a spectrum of weak acid K, values (39,46,47,5 1).…”

Section: The Heterogeneous Catalysis Systemmentioning

confidence: 98%

“…The atrazine -fulvic acid solution phase work has indicated that unionized carboxyl groups are hydrogen bonding sites. In addition, the only two catalysts for atrazine hydrolysis identified were hydrogen ions and unionized carboxyl groups (44)(45)(46)(47). Under field conditions, some atrazine could be sorbed from solution into water swollen particles, encountering an internal gel solution containing unionized carboxyl groups and free hydrogen ions.…”

Section: Introductionmentioning

confidence: 99%

“…Previous work with atrazine in fulvic acid solutions has demonstrated interactions between atrazine and unionized carboxyl groups and hydrogen ions (42)(43)(44)(45). The atrazine -fulvic acid solution phase work has indicated that unionized carboxyl groups are hydrogen bonding sites.…”

Section: Introductionmentioning

confidence: 99%

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Atrazine hydrolysis in aqueous suspensions of humic acid at 25.0 °C

Gamble¹,

Khan²

1988

Can. J. Chem.

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. J. Chem. 66,2605Chem. 66, (1988.The acidic properties of a Chemozemic humic acid were determined by equilibrium titration. The number of carboxyl groups is 2.828 (mmol/g) ? 0.5%. The results were used for an investigation of Bronsted acid catalysis of atrazine hydrolysis by a suspension of the humic acid. There is sufficient sorption so that the rates of change of atrazine and product hydroxyatrazine in solution differ both from each other and form the rate of atrazine conversion on the catalytic sites. An important objective of this work was the separate determination of the sorption equilibrium constants for atrazine and hydroxyatrazine, and the rate constant for atrazine conversion on the catalytic sites. All three constants are relevant to environmental research. The apparent rate constants for changes in solution are experimental artifacts however, not useful for such research. calculated-in terms of carboxyl sorption sites in the free acid form, the sorption equilibrium constants were 1.74 X lo2, CJ = 0.03 X 10' and 8.5 x lo2, a = 2.3 X lo2, for atrazine and hydroxyatrazine, respectively. The rate constant for conversion on catalytic sites ranges from 1.8 X lo-' day-' k 20% to 2.9 X lo-' day-' r 20%, for atrazine coverage of sites from 9.0 ( p,mol/g) to 1.0 ( p,mol/g).

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Section: Sorption Equilibriamentioning

confidence: 69%

Section: The Heterogeneous Catalysis Systemmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atrazine hydrolysis in aqueous suspensions of humic acid at 25.0 °C

Gamble¹,

Khan²

1988

Can. J. Chem.

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“…The early approach to sorption equilibrium was used for the calculation of sorption and desorption rate constants. soil interactions (1,(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). The extent to which the extractable iron and aluminum of this New Brunswick soil might be blocking carboxyl or clay sorption sites is unknown.…”

Section: Kinetics Chemical Speciation Experimentsmentioning

confidence: 99%

Atrazine in mineral soil: the analytical chemistry of speciation

Gamble¹,

Ismaily²

1992

Can. J. Chem.

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The HPLC–microfiltration method previously described for determining atrazine and hydroxyatrazine species in organic soil has been adapted to a mineral soil. The method was able to monitor atrazine concentrations of less than 1.0 × 10−6 M, which is over 40 times lower than the atrazine concentrations measured in the earlier organic soil experiments. During kinetics.experiments, it also monitored four free and sorbed chemical species instead of only one. Measurements were obtained with much better accuracy and productivity than can be obtained by conventional methods. The atrazine sorption capacity of the mineral soil was also measured. The analytical chemical data produced can support heterogeneous chemical kinetics calculations.

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Chemical Stoichiometry and Molecular Level Mechanisms as Support for Future Predictive Engineering Calculations

Gamble¹,

Langford

Bruccoleri

NATO Science Series

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The solution phase complexing of atrazine by fulvic acid: Equilibria at 25°c

Cited by 24 publications

References 23 publications

Atrazine hydrolysis in aqueous suspensions of humic acid at 25.0 °C

Atrazine hydrolysis in aqueous suspensions of humic acid at 25.0 °C

Atrazine in mineral soil: the analytical chemistry of speciation

Chemical Stoichiometry and Molecular Level Mechanisms as Support for Future Predictive Engineering Calculations

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