Photodegradation of orange I in the heterogeneous iron oxide–oxalate complex system under UVA irradiation
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- 作者：Jing Lei ; Chengshuai Liu ; Fangbai Li ; Xiaomin Li ; Shungui Zhou ; Tongxu Liu ; Minghua Gu and Qitang Wu
- 关键词：Iron oxide ; Oxalate ; Azo dye ; Photodegradation ; Photo-Fenton
- 刊名：Journal of Hazardous Materials
- 出版年：2006
- 出版时间：21 September 2006
- 年：2006
- 卷：137
- 期：2
- 页码：1016-1024
- 全文大小：641 K
文摘
To understand the photodegradation of azo dyes in natural aquatic environment, a novel photo-Fenton-like system, the heterogeneous iron oxide–oxalate complex system was set up with the existence of iron oxides and oxalate. Five iron oxides, including γ-FeOOH, IO-250, IO-320, IO-420 and IO-520, were prepared and their adsorption capacity was investigated in the dark. The results showed that the saturated adsorption amount (Γmax) was ranked the order of IO-250 > IO-320 > γ-FeOOH > IO-420 > IO-520 and the adsorption equilibrium constant (Ka) followed the order of IO-250 > IO-520 > γ-FeOOH > IO-420 > IO-320. The effect of initial pH value, the initial concentrations of oxalate and orange I on the photodegradation of orange I were also investigated in different iron oxide–oxalate systems. The results showed that the photodegradation of orange I under UVA irradiation could be enhanced greatly in the presence of oxalate. And the optimal oxalate concentrations () for γ-FeOOH, IO-250, IO-320, IO-420 and IO-520 were 1.8, 1.6, 3.5, 3.0 and 0.8 mM, respectively. The photodegradation of orange I in the presence of optimal was ranked as the order of γ-FeOOH > IO-250 > IO-320 > IO-420 > IO-520. The optimal range of initial pH was at about 3–4. The first-order kinetic constant for the degradation of orange I decreased with the increase in the initial concentration of orange I. Furthermore, the variation of pH, the concentrations of Fe3+ and Fe2+ during the photoreaction were also strongly dependent on the and iron oxides.