This study compares the electrochemical oxidation of acid orange 74 (AO 74), a typical metal complex azo dye, on four anode materials (Ru, IrO₂, PbO₂, and boron doped diamond (BDD)). The results show that the BDD electrode was quite efficient in the anodic oxidation of AO 74 with a 100% removal of AO 74 and an 84.3% removal of COD. Analyzing the active species at different electrodes, we reported that oxidation on an inert electrode primarily depends on direct oxidation and indirect oxidation of active radicals (OH and O₂⁻ for the BDD anode and OH for the PbO₂ anode), whereas active electrodes (Ru and IrO₂) primarily depend on direct oxidation. The UV–vis spectrum demonstrated that Cr³⁺ could be oxidized only on the BDD anode, proving that the BDD electrode has the highest oxidation potential. Similar organic intermediates species were observed on different electrodes by GC–MS. Furthermore, the different organic products are attributed to the difference in the oxidation ability of the electrodes. From the UV–vis spectrum and GC–MS analysis, we speculate that AO 74 was first degraded to aromatic compounds and pyrazole because of the cleavage of the azo-bond. Then it formed amides and organic acid because of the cleavage of the benzene ring, and finally CO₂ and H₂O were formed.

本研究比较了酸性橙 74 (AO 74)（一种典型的金属复合偶氮染料）在四种负极材料（Ru、IrO ₂、PbO ₂和掺硼金刚石 (BDD)）上的电化学氧化。结果表明，BDD 电极在 AO 74 的阳极氧化中非常有效，AO 74 去除率为 100%，COD 去除率为 84.3%。分析不同电极上的活性物质，我们报告说，惰性电极上的氧化主要取决于活性自由基（BDD 阳极为OH 和O ₂ ^-，PbO ₂阳极为OH）的直接氧化和间接氧化，而活性电极（ Ru和IrO ₂) 主要依赖于直接氧化。UV-vis 光谱表明 Cr ³⁺只能在 BDD 阳极上被氧化，证明 BDD 电极具有最高的氧化电位。通过 GC-MS 在不同的电极上观察到类似的有机中间体。此外，不同的有机产物归因于电极氧化能力的差异。从 UV-vis 光谱和 GC-MS 分析，我们推测 AO 74 由于偶氮键的断裂首先降解为芳香族化合物和吡唑。然后由于苯环裂解生成酰胺和有机酸，最后生成CO ₂和H ₂ O。