en |
Sorption behavior of nine chromium (III) organic complexes in soil
Luo, Z.; Wadhawan, A. & Bouwer, J.
Abstract
Sorption data were obtained with a Matawan soil and the following chromium (III) organic complexes:
chromium (III) ascorbate, chromium (III) glutamate, chromium (III) histidine, chromium (III) mandelate, chromium (III)
citrate, chromium (III) cysteine, chromium (III) serine, chromium (III) pyruvate and chromium (III) oxalate. The influence
of pH (2-12), ionic strength (0.005-1 M) and concentration of sorbate (1-10 mg/L) on the extent of sorption
was evaluated. The pH value did not influence the percent sorption at environmentally relevant pH 7. Ionic
strength between 0.005 and 0.01 M KNO3 did not influence the sorption. Sorption and desorption data obtained at pH
7, 0.01 M KNO3 and 1-10 mg/L for each chromium (III) organic complex were analyzed using Freundlich and Langmuir
models. The Freundlich model provided good fits for all of the chromium (III) organic complexes. Sorption data for
chromium (III) glutamate, chromium (III) pyruvate, chromium (III) oxalate, chromium (III) cysteine, chromium (III)
ascorbate and chromium (III) citrate were described well by the Langmuir model. Estimates for the
saturated sorption capacities were 141, 70.9, 36.5, 35.5, 28.6 and 4.4 μg/g, respectively. It was not possible to desorb
significant amounts of the previously sorbed chromium (III) organic complexes. At the same pH, ionic strength and
solid:liquid ratio, the order of the observed sorption to the Matawan soil from highest to lowest was chromium (III)
mandelate, chromium (III) glutamate, chromium (III) histidine, chromium (III) cysteine, chromium (III) serine, chromium
(III) pyruvate, chromium (III) oxalate, chromium (III) ascorbate and chromium (III) citrate.
Keywords
Chromium (III) ascorbate; Chromium (III) histidine; Chromium (III) citrate; Chromium (III) cysteine; Chromium (III) serine; Desorption; Freundlich isotherm
|