Abstract
The present study examined Cd solubility in pH 2-12 fresh and seawater media with and without humin to determine Cd species composition. The study, based on the Langmuir-Hinshelwood kinetics model, was conducted to determine the kinetic parameters of Cd(II) adsorption onto humin. We employed the Langmuir and Freundlich models to derive thermodynamic parameters. Aquo (Cd(H 2O) 6 2+) and chloro- (CdCl+ and CdCl2) complexes were responsible for Cd(II) adsorption onto humin. Results showed Cd as Cd(II) and Cd(H2O) 6 +2 was water soluble at 2 < pH < 7; with a portion of the soluble Cd precipitating as Cd(OH)2. The Cd(II) rate constant (k) in freshwater was 0.5 × 10-3 (min-1), occurring in a single phase, while in seawater fast and slow phase values for k were 31.88 × 10 -3 and 6.2 × 10-3 (min-1), respectively. The adsorption curves showed a better fit with the Langmuir than the Freundlich model.
Original language | English |
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Pages (from-to) | 352-357 |
Number of pages | 6 |
Journal | Bulletin of Environmental Contamination and Toxicology |
Volume | 92 |
Issue number | 3 |
DOIs | |
State | Published - 2014/03 |
Keywords
- Cadmium (II)
- Freshwater media
- Humin
- Seawater media
ASJC Scopus subject areas
- Toxicology
- Pollution
- Health, Toxicology and Mutagenesis