CoFe_(2)O_(4)/CoFe_(2)S_(4)活化PMS性能及机理

Performance and mechanism of PMS activation by CoFe_(2)O_(4)/CoFe_(2)S_(4)

通过简单的两步水热法合成CoFe_(2)O_(4)/CoFe_(2)S_(4)复合物.扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)及X射线光电子能谱(XPS)物性表征表明,CoFe_(2)O_(4)/CoFe_(2)S_(4)复合物由纳米片和纳米花颗粒混杂构成.与CoFe_(2)O_(4)相比,原位硫化引入轻微缺陷可以增加活性位点,从而促进CoFe_(2)O_(4)/CoFe_(2)S_(4)复合物的氧化还原活性,赋予CoFe_(2)O_(4)/CoFe_(2)S_(4)催化过一硫酸盐(PMS)体系更优异的氧化降解能力.进一步的参数优化实验表明,CoFe_(2)O_(4)/CoFe_(2)S_(4)与PMS体系氧化降解黄连素的最佳条件为1 mg/L CoFe_(2)O_(4)/CoFe_(2)S_(4)、0.8 mmol/L PMS、温度40℃、pH 7.0,该条件下黄连素的降解率在60 min内可达98.4%.CoFe_(2)O_(4)/CoFe_(2)S_(4)循环使用3次后,黄连素降解率依然在90%以上.电子顺磁共振(EPR)研究表明,CoFe_(2)O_(4)/CoFe_(2)S_(4)与PMS体系产生的主要活性氧化物种为SO^(-)_(4)·和HO·.自由基抑制实验证明,SO^(-)_(4)·是降解黄连素的主要活性物种.

The CoFe_(2)O_(4)/CoFe_(2)S_(4)composite is synthesized by a simple two-step hydrothermal method.Scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)characterization of physical properties show that the CoFe_(2)O_(4)/CoFe_(2)S_(4)composite is composed of nanosheets and nanoflower particles.Compared with CoFe2O4,the introduction of slight defects by in-situ vulcanization can increase the active sites,thereby promoting the redox activity of the CoFe_(2)O_(4)/CoFe_(2)S_(4)composite,and giving the CoFe_(2)O_(4)/CoFe_(2)S_(4)catalytic peroxymonosulfate(PMS)system a better oxidative degradation ability.Further parameter optimization experiments show that the optimal conditions for the oxidative degradation of berberine by the CoFe_(2)O_(4)/CoFe_(2)S_(4)and PMS system are 1 mg/L CoFe_(2)O_(4)/CoFe_(2)S_(4),0.8 mmol/L PMS,temperature of 40℃,pH of 7.0.Under these conditions,the degradation rate of berberine can reach 98.4%within 60 min.After three cycles of CoFe_(2)O_(4)/CoFe_(2)S_(4),the degradation rate of berberine is still above 90%.Electron paramagnetic resonance(EPR)studies show that the main active oxide species produced by the CoFe_(2)O_(4)/CoFe_(2)S_(4)and PMS system are SO^(-)_(4)· and HO·;free radical suppression experiments prove that SO^(-)_(4)· is the main active species that degrades berberine.