[Degradation of malachite green in aqueous solution by Fe3+/H2O2 catalyzed with EDTA].
This study found that the discolorization of malachite green solutions (0.01 mmol/L) was improved by Fe3+/H2O2 catalyzed with EDTA, at pH 7. Oxidation was carried out in presence of various hydrogen peroxide concentrations, in a wide range of temperature and EDTA concentration. It was found that oxidation with EDTA promoted the discolorization of MG from 43% to 98.3% as compared with the cases without EDTA. The discolorization of MG increased by 40% with the increase of EDTA concentration by 5 fold. The H2O2 concentration and temperature are higher, the discolorization of MG better, t-BuOH inhibited the improvement from EDTA. With the same total dosage of applied H2O2, the multiple steps addition did not show a much higher removal efficiency than that obtained by one step. OH free radical or an iron-oxo species may be the highly reactive oxidizing species, the latter may be the major oxidant. With the time, EDTA was a little oxidized.
Li
Chun-Juan
CJ
School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. juanzichengqun@126.com
Ma
Jun
J
Yu
Min
M
Zhang
Ying-Jie
YJ
D002384:Catalysis / Q000187:drug effects; D002614:Chelating Agents / Q000737:chemistry / Q000494:pharmacology; D004396:Coloring Agents / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry / Q000494:pharmacology; D005290:Ferric Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D012394:Rosaniline Dyes / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D002614:Chelating Agents; D004396:Coloring Agents; D005290:Ferric Compounds; D012394:Rosaniline Dyes; C005095:malachite green; D004492:Edetic Acid; D006861:Hydrogen Peroxide