| Autor: |
Meunier, Nathalie, Laroulandie, Jéro⁁me, Blais, Jean-François, Tyagi, Rajeshwar Dayal |
| Předmět: |
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| Zdroj: |
Journal of Environmental Engineering. Aug2003, Vol. 129 Issue 8, p693. 6p. |
| Abstrakt: |
The objectives of this work were to evaluate the effects of different parameters (Pb concentration, solution pH, Ca/Mg/Na/K salt concentrations) on Pb uptake by cocoa shells and to study the mechanisms of Pb removal in very acidic conditions. Sorption tests were conducted in shaken flasks with synthetic Pb solutions and 15 g/L cocoa shells. A lead uptake value of 161 mmol/kg was measured during the assay with [Pb][SUBi]53.66 mmol/L in solution at pH[SUBi]52.0 and T522°C. Results show that Pb uptake is very similar (14.5-16.0 mmol/kg) for an initial pH between 2.0 and 4.0, but a moderate decrease (10.8 mmol/kg) occurred when the initial pH51.5 and the [Pb][SUBi]=0.25 mmol/L. High Ca and Mg concentrations (2.35 mol/L) in solution induced a significant decrease in Pb removal by cocoa shells, whereas high K and Na concentrations did not affect Pb uptake by this sorbent. This suggests that Pb uptake by cocoa shells is controlled by ion-exchange reactions with Ca/Mg ions and protons. Finally, chemical tests have shown that carboxyl and amine functional groups play a dominant role in Pb uptake by cocoa shells. [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
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