A cost-effective method for treating oxalic acid (OA) during rare-earth extraction was developed using hydrodynamic cavitation (HC), ozone (O₃), and persulfate (PS) (HC@PS@O₃ process). The results showed that the optimal inlet pressure during HC was 5.10 kg cm⁻² with an orifice plate diameter of 2 mm. Moreover, HC was shown to activate PS, providing an alternative activation method to base or heat as an ultrasound activation method for chemical oxidation. O₃ was also shown to activate PS. For OA oxidation using the HC@PS@O₃ process, the optimum pH was 3 and the reaction rate increased with increasing temperature. Further, the activation energy was 36.69 kJ mol⁻¹. The mechanisms unveiled in this study will allow optimization of the HC@PS@O₃ process as a chemical oxidation technology. The kinetic investigation and economic evaluation of the HC@PS@O₃ process can be used as the basis for real wastewater treatment processes in the future.

开发了一种利用水力空化（HC），臭氧（O ₃）和过硫酸盐（PS）处理稀土萃取过程中草酸（OA）的经济有效方法（HC @ PS @ O ₃工艺）。结果表明，在HC期间的最佳入口压力为5.10 kg cm ^-2，孔板直径为2 mm。此外，显示出HC可以激活PS，从而提供了一种替代碱或热的激活方法，作为化学氧化的超声激活方法。O ₃也显示出激活PS。对于使用HC @ PS @ O ₃工艺的OA氧化，最佳pH为3，反应速率随温度升高而增加。此外，活化能为36.69 kJ mol ^-1。这项研究中揭示的机制将使作为化学氧化技术的HC @ PS @ O ₃工艺得以优化。HC @ PS @ O ₃工艺的动力学研究和经济评估可作为未来实际废水处理工艺的基础。