Background

Microbubbles have been widely used in advanced oxidation processes due to the generation of reactive oxygen species (ROS). In this study, the oxidation of ferrous ions in phosphoric acid solutions has been examined, focusing on the advanced oxidation activity of oxygen microbubbles.

Methods

Ultraviolet spectroscopy was used to determine the species and content of ROS. Electron spin-resonance spectroscopy and radical quenching experiments have confirmed the path of ROS generation.

Significant findings

It is concluded that the main ROS in the phosphoric acid solution was H₂O₂, and the generation of H₂O₂ was due to sequential single electron reduction of oxygen molecules. The amount of H₂O₂ generated was determined to be dependent on the temperature and phosphoric acid concentration, and under the optimal conditions (100 ºC and 7 mol/L H₃PO₄), 4.23 mmol/L H₂O₂ was produced from microbubbles. The kinetics analysis with respect to the oxidation of ferrous ions suggested significant reduction of reaction activation energy from greater than 56.1kJ/mol to 43.84 kJ/mol due to the oxidation via ROS, demonstrating that microbubble intensification is a facile and effective advanced oxidation method.

中文翻译：

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磷酸溶液中氧微泡产生活性氧及其在亚铁氧化中的应用

背景

由于活性氧 (ROS) 的产生，微泡已广泛用于高级氧化过程。在这项研究中，研究了磷酸溶液中亚铁离子的氧化，重点是氧微泡的高级氧化活性。

方法

紫外光谱用于确定ROS的种类和含量。电子自旋共振光谱和自由基猝灭实验已经证实了 ROS 的产生路径。

重要发现

可以得出结论，在磷酸溶液中的主ROS入H ₂ ö ₂，和H的生成₂ ö ₂，是由于氧分子的时序单一电子还原。H ₂ O _{2 的}生成量取决于温度和磷酸浓度，在最佳条件下（100 ºC 和 7 mol/LH ₃ PO ₄），4.23 mmol/LH ₂ O ₂是由微气泡产生的。关于亚铁离子氧化的动力学分析表明，由于通过 ROS 氧化，反应活化能从大于 56.1kJ/mol 显着降低到 43.84kJ/mol，表明微泡强化是一种简便有效的高级氧化方法。