Dong Yifan, Li Jinhua, Li Xuejin, Zhou Baoxue
1School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 People's Republic of China.
2Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240 People's Republic of China.
Nanomicro Lett. 2016;8(4):320-327. doi: 10.1007/s40820-016-0091-7. Epub 2016 May 4.
A significant promotion effect of low-molecular hydroxyl compounds (LMHCs) was found in the nano-photoelectrocatalytic (NPEC) degradation of fulvic acid (FA), which is a typical kind of humic acid existing widely in natural water bodies, and its influence mechanism was proposed. A TiO nanotube arrays (TNAs) material is served as the photoanode. Methanol, ethanediol, and glycerol were chosen as the representative of LMHCs in this study. The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value. The adsorption constants of FA, methanol, ethanediol, and glycerol were 43.44, 19.32, 7.00, and 1.30, respectively, which indicates that FA has the strongest adsorption property. The degradation performance of these organics and their mixture were observed in a thin-layer reactor. It shows that FA could hardly achieve exhausted mineralization alone, while LMHCs could be easily oxidized completely in the same condition. The degradation degree of FA, which is added LMHCs, improves significantly and the best promotion effect is achieved by glycerol. The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process. The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products. Among the chosen LMHCs, glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion. This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.
发现低分子羟基化合物（LMHCs）对富里酸（FA）的纳米光电催化（NPEC）降解具有显著的促进作用，富里酸是天然水体中广泛存在的一种典型腐殖酸，并提出了其影响机制。采用TiO纳米管阵列（TNAs）材料作为光阳极。本研究选择甲醇、乙二醇和甘油作为LMHCs的代表。利用瞬时光电流值研究了有机物在TNAs表面的吸附性能。FA、甲醇、乙二醇和甘油的吸附常数分别为43.44、19.32、7.00和1.30，这表明FA具有最强的吸附性能。在薄层反应器中观察了这些有机物及其混合物的降解性能。结果表明，FA单独难以实现完全矿化，而LMHCs在相同条件下可容易地被完全氧化。添加LMHCs的FA降解程度显著提高，甘油的促进效果最佳。LMHCs对FA降解的促进作用可能归因于NPEC过程中大量羟基自由基的形成。羟基自由基可促进FA及其中间产物的完全降解。在所选择的LMHCs中，具有三个羟基的甘油分子可产生最多的羟基自由基，并具有最佳的有效促进作用。这项工作为促进FA的NPEC降解提供了一种新方法，并为从污染水中去除腐殖质提供了一个方向。
