Treatment of nitrophenols by cathode reduction and electro-Fenton methods.
Treatment of nitrophenols by cathode reduction and electro-Fenton methods.
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DOI：
10.1016/j.jhazmat.2006.02.069
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发表时间：
2006-09
影响因子：
13.6
通讯作者：
S. Yuan;Meng Tian;Yanping Cui;Li Lin;Xiao-hua Lu
中科院分区：
文献类型：
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作者：
S. Yuan;Meng Tian;Yanping Cui;Li Lin;Xiao-hua Lu
研究了阴极还原法和电芬顿法对硝基酚类化合物的降解。对苯酚（Poh）、2-硝基苯酚（2-NP）、3-硝基苯酚（3-NP）、4-硝基苯酚（4-NP）和2，4-二硝基苯酚（2，4-DNP）进行了处理，得到了不同的降解序列。讨论了硝基酚类化合物的结构与活性的关系。以4-NP为模型化合物，采用循环伏安法研究了4-NP在石墨阴极和铂阳极上的电化学行为。不同的反应的4-NP的降解的贡献进行了研究，在分开的细胞。4-NP在阴极池中的降解比在阳极池中快得多。在阴极池中，通过引入曝气和Fe 2+，4-NP的降解显著增强。紫外-可见（UV-vis）光谱揭示了阳极电池和阴极电池中降解的不同反应途径。在未分隔槽中处理高浓度4-NP的实验表明，两种工艺对4-NP的去除率均在98%以上，总有机碳（TOC）的去除率均在13%左右，而后续的生物降解性试验表明，电芬顿可以消除4-NP的毒性，提高4-NP的生物降解性。在这两个过程中检测到的硝酸根和亚硝酸根离子的量可以忽略不计，表明没有直接释放的-NO2和-NO基团从4-NP及其降解中间体。通过气相色谱/质谱（GC/MS）检测中间体，如氢醌和苯并醌。电芬顿法降解4-NP的机理为阴极还原-羟基氧化。
This study deals with the degradation of various nitrophenols by cathode reduction and electro-Fenton methods. Phenols (Poh), 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP) are treated and different degradation sequences are obtained. The relationship between the structure and activities of nitrophenols is discussed. Using 4-NP as a model nitrophenol, the electrochemical behaviors on graphite cathode and Pt anode are analyzed by cyclic voltammetry. The contribution of different reactions to the degradation of 4-NP is investigated in divided cells. The degradation of 4-NP is much faster in the cathode cell than in the anodic cell. In the cathode cell, the degradation of 4-NP is significantly enhanced by the introduction of aeration and Fe2+. Ultraviolet–visible (UV–vis) spectra reveal different reaction pathways for the degradation in the anodic cell and cathode cell. Treatment of high concentration of 4-NP in the undivided cell shows that more than 98% removal of 4-NP and about 13% removal of total organic carbon (TOC) are obtained for both processes, while the subsequent biodegradability test shows that electro-Fenton can eliminate the toxicity and improve the biodegradability of 4-NP. Negligible quantity of nitrate and nitrite ions detected in both processes indicates that there is no direct release of –NO2and –NO groups from 4-NP and its degradation intermediates. Intermediates such as hydroquinone and bezoquinone are detected by gas chromatography/mass spectrum (GC/MS). The degradation pathway of 4-NP in electro-Fenton process is proposed as the cathode reduction followed by hydroxyl oxidation.