| 不同粒径零价铁活化过硫酸钠氧化降解酸性橙7的影响及动力学研究 |
| 摘要点击 3195 全文点击 1588 投稿时间：2014-01-17 修订日期：2014-04-23 |
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| 中文关键词 过硫酸钠(PS) 零价铁(ZVI) 酸性橙7(AO7) 粒径 降解动力学 中间产物 |
| 英文关键词 persulfate zero-valent iron acid orange 7 particle size degradation kinetics intermediate products |
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| 中文摘要 |
| 以偶氮染料酸性橙7（AO7）为目标污染物，研究了不同粒径零价铁（包括1 mm-ZVI、150 μm-ZVI、50 nm-ZVI）对活化过硫酸钠（PS）氧化降解AO7的影响，并探讨了这3种不同粒径的零价铁活化体系中AO7的降解动力学及中间产物. 结果表明，3种粒径零价铁均可以高效活化PS氧化降解AO7，反应90 min后，1 mm-ZVI、150 μm-ZVI 和50 nm-ZVI 活化体系对AO7的去除率分别为43%、97%和100%. AO7动力学方程拟合结果表明，1 mm-ZVI 和150 μm-ZVI 活化PS降解AO7是一级反应，50 nm-ZVI活化体系中AO7的降解是二级反应，这3种粒径零价铁活化PS降解AO7的速率常数大小顺序为50 nm-ZVI>150 μm-ZVI>1 mm-ZVI. 反应过程中1 mm-ZVI 反应后主要生成α-Fe2O3和少量Fe3O4，150 μm-ZVI表面的腐蚀产物主要是Fe3O4，而50 nm-ZVI的主要氧化物为α-Fe2O3和α-FeOOH. GC/MS检测出AO7降解中间产物有2-萘酚、邻甲酚、3-甲基-4-乙基苯酚、邻苯二甲酰亚胺、邻苯二甲酸等，AO7溶液吸收光谱的变化特征及GC/MS检测结果表明3种粒径零价铁活化PS氧化降解AO7的途径可能存在差异. |
| 英文摘要 |
| This research described the heterogeneous reactions of persulfate with different particle sizes of zero-valent iron (including 1 mm-ZVI,150 μm-ZVI,50 nm-ZVI) for degradation of acid orange 7(AO7), and studied the kinetics and intermediate products of AO7 under these systems. The results demonstrated that these three types of ZVI were efficient in promoting the degradation of AO7, the degradation efficiencies of AO7 were 43%, 97%, and 100% within 90 min respectively, in the 1 mm-ZVI,150 μm-ZVI and 50 nm-ZVI systems, respectively. With the results of kinetic fitting models, the pseudo first-order kinetics exhibited better fitting results in the 1 mm-ZVI,150 μm-ZVI systems, while the second-order kinetics exhibited better fitting results in the 50 nm-ZVI system. And the different ZVI types exhibited difference on the AO7 degradation rate constant, which ranged as 50 nm-ZVI>150 μm-ZVI>1 mm-ZVI. The iron corrosion products coating on the ZVI after reaction were composed of α-Fe2O3 and some Fe3O4 in the 1 mm-ZVI system while that consisted of Fe3O4 and α-Fe2O3, FeOOH respectively, in the150 μm-ZVI and 50 nm-ZVI systems,. Which were identified by scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) and Raman spectroscopy. Some intermediate products, including 2-naphthalenol, 2-methylphenol, 4-ethyl-3-methyl-phenol, isoindole-1,3-dione and phthalic acid et al. were identified by GC/MS measurement. Both UV-vis absorbance spectra and GC/MS determination indicated that there was difference in degradation paths of AO7 between the three systems. |
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