Abstract:

The iron-cobalt bimetallic composite catalyst was prepared by solvothermal method followed by high-temperature calcination to activate peroxymonosulfate (PMS) to degrade the azo dye orange Ⅱ (OGⅡ). The composites were characterized by X-ray diffractometer, scanning electron microscope, vibrating sample magnetometer and X-ray photoelectron spectrometer. The effects of cobalt compound amount, different removal systems, catalyst dosage, PMS dosage, pollutant concentration, pH and coexisting anions on the degradation effect of OGⅡ were investigated, and the reuse effect of iron-cobalt composite catalyst was explored. The experimental results show that the iron-cobalt composite catalyst can effectively activate PMS to degrade OGⅡ. When n(Co₃O₄)∶ n(Fe₂O₃)=0.1, the dosage of catalyst is 1.0 g/L, the dosage of PMS is 0.4 mmol/L, the concentration of OGⅡ is 30 mg/L and pH of solution is 6.2, after 60 min of reaction, the degradation rate of OGⅡ reached 95.81%, the degradation process conformed to the pseudo-first-order kinetic model, and the maximum reaction rate constant was 0.0491 min^-1. The composite catalyst still had a degradation rate of 68.85% to OGⅡ after 4 cycles. ·SO${}_{\mathrm{4}}^{-}$, ·OH and ¹O₂ are reactive oxygen species produced in the reaction system, and ¹O₂ plays a major role in the degradation of OGⅡ.

Key words: ferromagnet, spinel, composites, activation, persulfate, degradation

摘要：

采用溶剂热法后高温煅烧的方式制备了铁钴双金属复合催化剂，用以活化过一硫酸盐(PMS)降解偶氮染料金橙Ⅱ(OGⅡ)。通过X射线衍射仪、扫描电子显微镜、振动样品磁强计和X射线光电子能谱仪等仪器对复合材料进行了表征。考察了钴复合量、不同去除体系、催化剂投加量、PMS投加量、污染物浓度、pH和共存阴离子等因素对OGⅡ降解效果的影响，并探究了铁钴复合催化剂重复利用的效果。实验结果表明，铁钴复合催化剂可以有效活化PMS降解OGⅡ，在n(Co₃O₄)∶n(Fe₂O₃)=0.1、催化剂投加量为1.0 g/L、PMS投加量为0.4 mmol/L、OGⅡ浓度为30 mg/L、溶液pH为6.2的条件下，反应60 min后，OGⅡ的降解率达到了95.81%，其降解过程符合准一级反应动力学模型，最大反应速率常数为0.0491 min^-1。复合催化剂使用4次后对OGⅡ仍有68.85%的降解率。·SO${}_{\mathrm{4}}^{-}$、·OH和¹O₂是反应体系产生的活性氧物种，¹O₂在OGⅡ的降解中起主要作用。

关键词: 铁磁体, 尖晶石, 复合材料, 活化, 过硫酸盐, 降解