Parameters influencing Cr(VI) removal from water using Fe(II)
Temperature, pH and dissolved oxygen strongly influence the aqueous Cr(VI) removal process using Fe(II). Reaction rate was increased by increasing pH from 6 to 8. At 25 oC and pH values higher than 7, maximum Cr(VI) removal was achieved at a reaction time equal or less than 5min, which in turn resulted in a second–order rate {d[Cr(VI)]/dt = kobs[Fe(II)][Cr(VI)]} coefficient kobs > 1x104 M-1s-1.
Dissolved oxygen strongly competed with Cr(VI) in Fe(II) oxidation increasing reaction ratio [Fe(II)]/[Cr(VI)] from an almost stoichiometric value 3.1 at pH 6 to 25 at pH 8. Reaction rate was also increased by increasing temperature from 10oC to 40oC, confirming the endothermic character of the reaction. Pilot scale experiments proved that the sand bed contributed to Fe(II) oxidation, improving in turn the removal of chromium recipitates. This was attributed to ferric oxy-hydroxides retained on the sand bed, whose surface hydroxyl groups coordinated with Fe(II) increasing its oxidation rate and removal.
| Copyright: | © Aristotle University of Thessaloniki | |
| Quelle: | 2nd International Conference 2009 (Juni 2009) | |
| Seiten: | 6 | |
| Preis inkl. MwSt.: | € 5,00 | |
| Autor: | M. Mitrakas  A. Pantazatou Roxani Tzimou-Tsitouridou C. Sikalidis | |
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