Our previous work indicated that hydroxyl radicals (HO•) exist in the filtrate of Al + acid + HO system. In this work, the behind mechanism was investigated in detail and a new catalyst for advanced oxidation processes (AOPs) was found for the first time. It was revealed that metastable hexacoordinated aluminum cluster ions ([Al(HO)]*), which are produced by Al-water reaction, can be as direct catalyst and decompose HO into HO• in a full pH range (2.5–12.0), and efficiently degrade and mineralize organic pollutants without precipitates. Of course, their catalytic activity in acidic aqueous solution is higher than that in neutral and alkaline solutions. Furthermore, [Al(HO)]* cluster ions have an excellent recyclability and their catalytic efficiency for generating HO• and degrading phenol and bisphenol A (BPA) did not decrease significantly even the cycling number was up to ten. Meanwhile, [Al(HO)]* cluster ions have a long lifetime and can keep their catalytic activity for more than three months under ambient condition. The present finding shows that Al ions can be also as a cost-efficient catalyst for AOP technology.

中文翻译：

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铝-水反应产生亚稳态铝簇离子及其在高级氧化过程中的应用


我们前期的工作表明，Al+酸+H2O体系的滤液中存在羟基自由基（HO•）。在这项工作中，详细研究了其背后的机制，并首次发现了一种用于高级氧化过程（AOP）的新型催化剂。研究表明，铝-水反应产生的亚稳态六配位铝簇离子（[Al(H2O)]*）可以作为直接催化剂，在整个pH范围（2.5-12.0）内将H2O分解为H2O•，高效降解、矿化有机污染物，且不产生沉淀。当然，它们在酸性水溶液中的催化活性高于中性和碱性溶液中的催化活性。此外，[Al(H2O)]*团​​簇离子具有优异的可循环性，即使循环次数达到10次，其生成HO·以及降解苯酚和双酚A（BPA）的催化效率也没有明显下降。同时，[Al(H2O)]*簇离子寿命长，在环境条件下可以保持催化活性三个月以上。目前的发现表明，Al 离子也可以作为 AOP 技术的经济高效的催化剂。