| 水体中腐殖酸与Fe(Ⅲ)的络合物对2,4-D光降解的作用 |
| 摘要点击 2459 全文点击 2218 投稿时间：2009-03-10 修订日期：2009-05-26 |
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| 中文关键词 腐殖酸 铁 络合物 2,4-二氯苯氧乙酸（2,4-D） 光降解 |
| 英文关键词 humic acids (HAs) iron complex 2,4-dichlorophenoxyacetic acid (2,4-D) photodegradation |
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| 中文摘要 |
| 为探讨水体中腐殖酸（humic acids，HAs）和铁元素对共存系统中环境污染物迁移转化的影响，利用红外光谱、紫外/可见吸收光谱和荧光光谱仪等手段表征了腐殖酸和Fe(Ⅲ)共存时的结构形态．结果表明，二者形成了稳定的络合物．电子顺磁共振图谱表明,腐殖酸、Fe(Ⅲ)以及HAs-Fe(Ⅲ)络合物在<λ = 355 nm光照下均能产生·OH．氙灯光照下（λ> 290 nm），除草剂2,4-二氯苯氧乙酸（2,4-dichlorophenoxyacetic acid，2,4-D）的光降解遵循准一级动力学过程．单纯2 |
| 英文摘要 |
| To elucidate the roles of humic acids (HAs) and iron on the environmental fate and transport of organic pollutants in natural water,the interactions of HAs with Fe(Ⅲ) were characterized by Fourier transform infrared spectroscopy (FTIR) spectra,Ultraviolet-visible (UV-vis) spectra and fluorescence spectra,indicating the formation of HAs-Fe(Ⅲ) complex. Electron paramagnetic resonance (EPR) spectra show ·OH radicals are generated and can participate in the photoreaction in solutions containing HAs,Fe(Ⅲ) and HAs-Fe(Ⅲ) complex. Under Xe lamp irradiation (λ>290 nm),the photodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D),as a kind of herbicide,followed the pseudo-first-order reaction kinetics. The pseudo-first-order rate constant of 2,4-D photodegradation with the presence of only 2,4-D (2 mg·L-1) was 0.007 h-1. In the presence of HAs (5 mg·L-1),Fe(Ⅲ) (0.2 mmol·L-1) and HAs-Fe(Ⅲ) complex,the rate constants of 2,4-D degradation were 0.004,0.034 and 0.046 h-1,respectively. It was interesting to note that in the existence of HAs,2,4-D photodegradation was inhibited. While in the presence of Fe(Ⅲ),2,4-D photodegradation was enhanced. Furthermore,in the coexistence of HAs and Fe(Ⅲ),HAs-Fe(Ⅲ) complex showed better increased effect on the photodegradation of 2,4-D than Fe(Ⅲ) alone. |
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