碳化泡沫负载Co_(3)O_(4)活化过硫酸盐降解罗丹明B

Carbonized Foam Supported Co_(3)O_(4) Activated Peroxymonosulfate Towards Rhodamine B Degradation

Co_(3)O_(4)具有优良的活化过硫酸盐的性能而受到人们的重视,但Co_(3)O_(4)粉体易团聚、使用过程中难以分离、易流失和重复利用率差等问题严重制约了其实际应用.通过水热法制备碳化三聚氰胺泡沫负载Co_(3)O_(4)非均相催化剂.采用X-射线衍射仪(XRD)和扫描电子显微镜(SEM)对催化剂的结构和表面形貌进行分析.研究不同因素对催化剂活化过硫酸氢钾(PMS)降解罗丹明B(RhB)的性能.其最优催化工艺参数:催化剂投加量为35 mg·L^(-1)、PMS质量浓度为50 mg·L^(-1)和pH为7、RhB初始质量浓度为10 mg·L^(-1),30 min反应后对RhB降解率为98%.结果表明,增大碳化泡沫负载Co_(3)O_(4)非均相催化剂投加量和PMS质量浓度能明显提高对RhB的降解率;而增加RhB初始质量浓度和提高pH值会明显抑制RhB的降解率.催化反应过程符合准一级动力学方程.温度对RhB降解率的影响符合阿伦尼乌斯模型,降解过程是表面反应控制.水体中Cl^(-)对RhB降解有轻微的促进作用,NO_(3)^(-)和SO_(4)^(2-)则表现出不同程度的抑制,而CO_(3)^(2-)明显抑制RhB降解.自由基捕获实验结果表明SO_(4)^(-)·是RhB降解的主要活性自由基.经过4次循环使用后催化剂对RhB降解率仍达到93%以上.

Co_(3)O_(4)has received much attention because of its excellent performance in activating peroxymonosulfate.However,the practical application of Co_(3)O_(4)has been seriously restricted by the problems of agglomeration of Co_(3)O_(4),difficult separation,easy loss,and poor recycling.In this study,the CMF/Co_(3)O_(4)heterogeneous catalyst was prepared using the hydrothermal method.The crystal structure and morphology of CMF/Co_(3)O_(4)were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).Rhodamine B(RhB)degradation was employed as a model test for evaluating potassium peroxymonosulfate(PMS)activation.The degradation rate of RhB can reach 98%in the catalyst dosage of 35 mg·L^(-1),PMS concentration of 50 mg·L^(-1),pH of 7,and RhB initial concentration of 10 mg·L^(-1) after a 30 min reaction.The results showed that the degradation rate of RhB could be significantly improved by increasing the amount of CMF/Co_(3)O_(4)heterogeneous catalyst and the mass concentration of PMS.The degradation rate of RhB can be inhibited by increasing the initial mass concentration of RhB and pH value.The process of degradation of RhB can be fitted by using the pseudo first-order kinetics model.The effect of temperature on the degradation rate of RhB conformed to the Arrhenius model,and the degradation process was a surface reaction-controlled process.The results of the free radical capture experiment showed that the sulfate radicals were the dominant active species for RhB degradation.After four cycles,the degradation rate of RhB still remained above 93%with CMF/Co_(3)O_(4)catalyst.