Kinetics and mechanisms of aluminum adsorption on kaolinite using a two-site nonequilibrium transport model
Kinetics of Al adsorption on Ca-kaolinite at selected concentrations, pH, and column lengths were studied using a miscible displacement technique. Observed breakthrough curves (BTC) for continuous injection of pH 4.3, 0.75 to 7.75 g mL S Al solution were well-described by a two-site nonequilibrium transport model which assumes that sorption sites can be divided into two fractions: instantaneous equilibrium sites and sites following first-order reversible kinetics. Independent verification of the fitted parameter US , related to the fraction of type-1 equilibrium sites, was possible by assuming negative surface charge sites of kaolinite were in local equilibrium with the solution phase. Confirmation of the fitted parameter R, which is a measure of the total Al adsorbed, was not possible due to the nonsingular nature of the equilibrium adsorption isotherm. First-order rate coefficients ( ) for Al adsorption on kaolinite were unaffected by column length. Effects of influent Al concentration on were small but suggested that kinetic reaction of Al with kaolinite was not strictly first-order. Decreasing the pH of influent solution from 4.3 to 4.0, eliminated type-2 kinetic sites. These effects indicate that kinetic reactions involve Al polymerization on kaolinite while equilibrium reactions reflects Ca-Al exchange.
- Research Organization:
- Virginia Polytechnic Institute and State Univ., Blacksburg
- DOE Contract Number:
- AS05-83ER60179
- OSTI ID:
- 6183594
- Journal Information:
- Soil Sci. Soc. Am. J.; (United States), Vol. 49:4; Conference: 48. annual meeting, Soil Science Society of America, Chicago, IL, USA, 1-6 Dec 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kaolinite dissolution and precipitation kinetics at 22oC and pH4
The role of colloidal kaolinite in the transport of cesium through laboratory sand columns
Related Subjects
ALUMINIUM
CHEMICAL REACTION KINETICS
KAOLINITE
ADSORPTION
MATHEMATICAL MODELS
PH VALUE
RESPONSE MODIFYING FACTORS
SOIL CHEMISTRY
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CHEMISTRY
ELEMENTS
KINETICS
METALS
MINERALS
OXYGEN COMPOUNDS
REACTION KINETICS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SORPTION
510200* - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)
510100 - Environment
Terrestrial- Basic Studies- (-1989)