The effect of the ionic strength on the adsorption isotherms of nickel on silica

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Journal of Colloid and Interface Science

DOI:https://doi.org/10.1006/jcis.1997.4840· OSTI ID:514741

Kosmulski, M ^[1]

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1. Forschungszentrum Karlsruhe (Germany). Inst. fuer Nukleare Entsorgungstechnik

Isotherms of adsorption of Ni(II) on silica from 0.01 M NaClO{sub 4} are almost linear with a log-log slope of 0.95, and the percentage of uptake at a given pH is insensitive to the initial Ni concentration. At higher ionic strengths ({ge}0.1 mol/dm{sup 3}) two kinds of behavior are observed. For low Ni concentrations the adsorption is approximately equal to that observed at lower ionic strengths. For higher Ni concentrations (but still much lower than the concentration of surface sites) the Ni adsorption from 0.1 and 0.3 mol/dm{sup 3} NaClO{sub 4} is lower than the adsorption from 0.01 M NaClO{sub 4} by a factor of 2 (pH 9) to 3 (pH 8). When water is replaced by a mixed solvent (e.g., 2% aqueous DMSO, THF, methanol, glycerol) the Ni adsorption isotherms obtained in the presence of 0.1 /mol/dm{sup 3} NaClO{sub 4} are linear with a log-log slope of 0.95. These adsorption isotherms are rather insensitive to the nature and concentration of the organic cosolvent. It is impossible to explain the Ni adsorption curves over the entire studied range of initial concentrations and ionic strengths in terms of surface complexation model, unless the Boltzmann factor is properly corrected.

• OSTI ID: 514741
• Journal Information: Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 1 Vol. 190; ISSN 0021-9797; ISSN JCISA5
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ADSORPTION ISOTHERMS
CONCENTRATION RATIO
NICKEL
ORGANIC SOLVENTS
PH VALUE
SILICA
SORPTIVE PROPERTIES