Reactions of aqueous aluminum species at mineral surfaces

Journal Article · Wed Jan 01 04:00:00 EST 1975 · Geol. Surv. Water-Supply Pap. (U.S.); (United States)

OSTI ID:5407442

Brown, D W; Hem, J D

Aqueous aluminum solutions containing 4.5 x 10/sup -4/ molar aluminum in 0.01 molar NaClO/sub 4/ were partly neutralized with NaOH to give OH:AL mole ratios from 1.40 to 2.76. Measured amounts of montmorillonite, kaolinite, volcanic ash, or feldspathic sand were added to provide an area of inert surface. Reactions that occurred during 100 days of aging were compared with those in similar solutions without added surfaces, studied in earlier work. Adsorption of monomeric species Al(H/sub 2/O)/sub 6//sup +3/, AlOH(H/sub 2/O)/sub 5//sup +2/, and Al(OH/sub 2/)(H/sub 2/O)/sub 4//sup +/ on the added surfaces follows a cation exchange mass law equilibrium model, and adsorption is essentially complete in 1 hour. Only minor changes in monomeric aluminum species occurred after that. Rapid adsorption of polynuclear aluminum hydroxide species also occurs and follows the pattern of the Langmuir adsorption isotherm. In the absence of surfaces, the polynuclear ions slowly increase in size and become microcrystalline gibbsite during aging. Electron micrographs showed microcrystalline gibbsite was present on surfaces after aging only 2 days. However, the analytical data suggest this material must have been adsorbed after it had already attained a near-crystalline state. Adsorbed polynuclear aluminum hydroxide species were not extensively converted to microcrystalline gibbsite during 100 days of aging.

• OSTI ID: 5407442
• Journal Information: Geol. Surv. Water-Supply Pap. (U.S.); (United States), Journal Name: Geol. Surv. Water-Supply Pap. (U.S.); (United States) Vol. 1827-F; ISSN XIWSA
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACIDIFICATION
ADSORPTION
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM HYDROXIDES
ALUMINIUM SILICATES
CHEMICAL REACTIONS
CLAYS
ENVIRONMENTAL EFFECTS
GIBBSITE
HYDROGEN COMPOUNDS
HYDROXIDES
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KAOLINITE
LAND POLLUTION
MATERIALS
MINERALS
MONTMORILLONITE
OXIDE MINERALS
OXYGEN COMPOUNDS
POLLUTION
SAND
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SORPTION