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Details for article 6 of 7 found articles
| Title: |
Mass-transfer processes of chromium(VI) adsorption onto guava seeds |
| Author: |
Abdelwahab, O. Sikaily, A. El Khaled, A. Nemr, A. El |
| Appeared in: |
Chemistry & ecology |
| Paging: | Volume 23 (2007) nr. 1 pages 73-85 |
| Year: |
2007-02 |
| Contents: |
The chromium(VI) biosorption onto guava seeds, as an alternative method for Cr6+ removal from aqueous solutions, was investigated. The parameters affecting kinetics and equilibrium of Cr6+ adsorption onto guava seeds were studied. An external mass-transfer diffusion coefficient k and intra-particle diffusion coefficient ki were determined to measure the rate-limiting step of adsorption. A single external mass-transfer diffusion model and intra-particle diffusion models were used. The effects of initial pH, sorbent mass, and initial Cr6+ concentrations on mass-transfer coefficients were investigated. The external mass-transfer coefficient has an average value of 7.2×10-3 cm s-1, while the intra-particle mass-transfer diffusion coefficient was 0.34 mg g-1 min-0.5. This indicates that external diffusion to the guava seeds surface and intra-particle diffusion are both involved in the sorption process. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models with an average correlation coefficient R2=0.98. The maximum removal of Cr6+ was obtained at pH 1 (about 100% for adsorbent dose of 15 g l-1 and 25 mg l-1 initial concentration of Cr6+). The results indicated that the guava seeds exhibit acceptable sorption capacity. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 6 of 7 found articles
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