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Removal of Cr(VI) from aqueous environments using micelle-clay adsorption.

Qurie M, Khamis M, Manassra A, Ayyad I, Nir S, Scrano L, Bufo SA, Karaman R - ScientificWorldJournal (2013)

Bottom Line: Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions.Langmuir adsorption isotherm fitted the experimental data giving significant results.The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Chemical Technology, Faculty of Science and Technology, Al-Quds University, 20002 Jerusalem, Palestine ; Department of Science, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy.

ABSTRACT
Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques.

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Effect of contact time on the removal of chromium by micelle-clay complex at pH 1 (♦) and pH 6 (■). Initial concentration of Cr(VI) = 50 mg L−1, temperature = 25.0 ± 0.2°C, and adsorbent dosage = 5.0 g L−1. Data represent averages of total-Cr triplicate measurements (AAS) ± SE.
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fig4: Effect of contact time on the removal of chromium by micelle-clay complex at pH 1 (♦) and pH 6 (■). Initial concentration of Cr(VI) = 50 mg L−1, temperature = 25.0 ± 0.2°C, and adsorbent dosage = 5.0 g L−1. Data represent averages of total-Cr triplicate measurements (AAS) ± SE.

Mentions: Figure 4 summarizes the effect of contact time on the percentage of chromium removed by the micelle-clay complex at different initially adjusted pH values, as measured by AAS. In the experiment performed at pH = 1, the removal percentage increased during the first 20 min, and then gradual decrease up to the equilibrium was reached. At pH = 6, the adsorption of Cr(VI) seems initially affected by the competition of hydroxyl ions, but after 60 min the adsorption equilibrium was restored irrespective of pH. It can be speculated that the binding of Cr(VI) to micelle-clays complex was initially regulated by acidity of solution, and then, as discussed above, reduction of Cr(VI) to Cr(III) can take place at a later stage, and chromium remains in the solution as unadsorbed fraction due to the positive charge of Cr(III). Similar results have been also reported in the literature using other low cost adsorbents [21, 22, 24–28].


Removal of Cr(VI) from aqueous environments using micelle-clay adsorption.

Qurie M, Khamis M, Manassra A, Ayyad I, Nir S, Scrano L, Bufo SA, Karaman R - ScientificWorldJournal (2013)

Effect of contact time on the removal of chromium by micelle-clay complex at pH 1 (♦) and pH 6 (■). Initial concentration of Cr(VI) = 50 mg L−1, temperature = 25.0 ± 0.2°C, and adsorbent dosage = 5.0 g L−1. Data represent averages of total-Cr triplicate measurements (AAS) ± SE.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814082&req=5

fig4: Effect of contact time on the removal of chromium by micelle-clay complex at pH 1 (♦) and pH 6 (■). Initial concentration of Cr(VI) = 50 mg L−1, temperature = 25.0 ± 0.2°C, and adsorbent dosage = 5.0 g L−1. Data represent averages of total-Cr triplicate measurements (AAS) ± SE.
Mentions: Figure 4 summarizes the effect of contact time on the percentage of chromium removed by the micelle-clay complex at different initially adjusted pH values, as measured by AAS. In the experiment performed at pH = 1, the removal percentage increased during the first 20 min, and then gradual decrease up to the equilibrium was reached. At pH = 6, the adsorption of Cr(VI) seems initially affected by the competition of hydroxyl ions, but after 60 min the adsorption equilibrium was restored irrespective of pH. It can be speculated that the binding of Cr(VI) to micelle-clays complex was initially regulated by acidity of solution, and then, as discussed above, reduction of Cr(VI) to Cr(III) can take place at a later stage, and chromium remains in the solution as unadsorbed fraction due to the positive charge of Cr(III). Similar results have been also reported in the literature using other low cost adsorbents [21, 22, 24–28].

Bottom Line: Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions.Langmuir adsorption isotherm fitted the experimental data giving significant results.The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Chemical Technology, Faculty of Science and Technology, Al-Quds University, 20002 Jerusalem, Palestine ; Department of Science, University of Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy.

ABSTRACT
Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques.

Show MeSH
Related in: MedlinePlus