The role of oxalate in 4-chlorophenol (4-CP) oxidation by permanganate (Mn(VII)) was explored in this study. The performance of oxalate was heavily depended on pH and oxalate concentration. 4-CP degradation by Mn(VII) was significantly enhanced at pH 4.0–6.0 in the presence of oxalate, while negligible influence was observed at pH 7.0–9.0. The oxalate plays a dual role in Mn(VII) oxidation over the pH range of 4.0–6.0: one is the chelate, which coordinates with Mn(III) to form Mn(III)-oxalate complexes, and the other is the reductant, which reacts with Mn(III) to form Mn(II). The stable Mn(III)-oxalate complexes can work as an efficient oxidant for 4-CP. While their unstable counterparts, due to the lower concentration of oxalate or the higher pH, would auto-decomposed to MnO₂ and Mn(II), and then the MnO₂ works as both a catalyst and an oxidant for the decomposition of 4-CP.

本研究探讨了草酸盐在高氯酸盐（Mn（VII））氧化4-氯苯酚（4-CP）中的作用。草酸盐的性能在很大程度上取决于pH值和草酸盐浓度。在草酸存在下，pH 4.0-6.0时，Mn（VII）对4-CP的降解作用明显增强，而在pH 7.0-9.0时，观察到的影响可忽略不计。草酸盐在4.0-6.0的pH范围内对Mn（VII）的氧化起双重作用：一种是螯合物，与Mn（III）配合形成Mn（III）-草酸盐络合物，另一种是还原剂，它与Mn（III）反应形成Mn（II）。稳定的草酸锰（III）配合物可作为4-CP的有效氧化剂。虽然它们不稳定的对应物，由于较低的草酸盐浓度或较高的pH值，它们会自动分解为MnO ₂和Mn（II），然后分解为MnO。₂作为4-CP分解的催化剂和氧化剂。