硼酸和磷酸对PMS/Co2+均相催化氧化有机物的影响因素与机制

基于过一硫酸盐（PMS）的高级氧化方法被广泛用于有机污染物的降解.本研究以富电子偶氮染料酸性橙7（AO7）为目标有机物，探究了在硼酸（路易斯酸）和磷酸（布朗斯台德酸）两种不同类型的缓冲液中，PMS/Co²⁺均相催化氧化降解有机物的差异、影响因素及作用机制.PMS/Co²⁺均相催化氧化体系在磷酸盐缓冲液中降解有机物的k值高于其在硼酸盐缓冲液中，而在磷酸盐缓冲液中的前10 s降解率却低于其在硼酸盐缓冲液中.该体系氧化降解有机物在硼酸和磷酸缓冲液中的差异随着缓冲液、PMS浓度、Co²⁺浓度和pH的变化而有所不同.PMS/Co²⁺体系在磷酸盐缓冲液中主要通过SO₄^-·或·OH氧化降解有机物，在硼酸盐缓冲液中，PMS/Co²⁺体系主要通过非自由基途径（¹O₂）降解有机物.该研究将为PMS均相催化中不同类型缓冲液的应用提供参考.

Role of Borate and Phosphate Buffers in the Degradation of Organic Compounds in a PMS/Co2+ System: Influencing Factors and Mechanisms

Peroxymonosulfate(PMS)-based advanced oxidation processes were widely used for the degradation of organic pollutants. Electron-rich azo dye Acid Orange 7(AO7) was selected as the target organic matter in this work. The differences, influencing factors, efficiency, and mechanisms of a PMS/Co²⁺ homogeneous system in the degradation of organic pollutants with two different buffers of boric acid(Lewis acid) and phosphoric acid(Bronstede acid) were investigated. The k value of AO7 degradation in the PMS/Co²⁺ homogeneous system with phosphate buffer was greater than that with borate buffer, but the degradation percentage during the first 10 seconds of the reaction was lower in the former case. These differences were affected by buffer concentration, the PMS and Co²⁺ dosages, and pH. In the phosphate buffer, ·OH or SO₄^-· contributed to organic degradation in the PMS/Co²⁺ system, while in the borate buffer, the nonradical pathway(¹O₂) made a critical contribution to the removal of organics. This study provides a reference for the application of different types of buffers in the homogeneous catalysis of PMS.