纳米立方体PBA-Fe_(1)Mn_(2)活化过一硫酸盐降解偶氮有机物

Nanoscale PBA-Fe_(1)Mn_(2)activated peroxymonosulfate for degradation of Azo organic

采用油浴-水热两步法制备纳米立方体铁锰双金属催化剂普鲁士蓝类似物PBA-Fe_(1)Mn_(2),利用纳米立方体结构催化剂接触面积大、活性位点多的特点,活化过一硫酸盐(PMS)降解活性黑5(RBK5).通过X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)对催化剂进行表征,表明合成的催化剂PBA-Fe_(1)Mn_(2)具有普鲁士蓝立方体结构.铁锰双金属的协同作用与立方体结构上的活性位点有效地提高了RBK5的降解效率.在初始pH值为7、催化剂投加量为0.2g/L、PMS浓度为2mmol/L的最优条件下,在60min内可使10mg/L的RBK5脱色率高达100%.自由基淬灭实验及EPR表明该体系中HO·、SO_(4)^(-)·参与RBK5的降解.其中催化剂表面的羟基自由基为主要作用基团.XPS反映了铁锰元素存在价态变化以及双金属间的协同作用,不同铁锰价态变化的循环过程促进催化剂的活化.最后,根据XPS和三维荧光光谱分析降解机制,表明RBK5在体系中被降解.

The nano-scale Fe-Mn bimetallic catalyst of Prussian blue analogue PBA-Fe_(1)Mn_(2),was prepared by a two-step oil bath-hydrothermal method.The large contactable area and many active sites of the nanoscale catalyst was utilized to activate peroxymonosulfate(PMS)for reactive black 5(RBK5)degradation.Serious catalyst were characterized by X-ray powder diffractometry(XRD),scanning electron microscopy(SEM),and Fourier transform infrared spectroscopy(FTIR),indicating that the synthesized catalyst PBA-Fe_(1)Mn_(2)had structure of Prussian blue cubes.The synergistic effect of FeMn bimetal with the active site on the cubic structure effectively enhanced the degradation efficiency of RBK5.Under the optimal conditions of initial pH=7,catalyst dosage of 0.2g/L and PMS concentration of 2mmol/L,the decolorization efficiency of 10mg/L RBK5 could reach 100%within 60min.The free radical quenching experiments and EPR showed that HO·and SO_(4)^(-)·in this system were involved in the degradation of RBK5 and the hydroxyl radicals on the catalyst surface were the main acting groups.XPS reflected the changes of FeMn valence states,proved the synergistic interaction between bimetals,and identified the promotion of activity via FeMn valence cyclizing process.Finally,the degradation mechanism was analyzed according to XPS and 3D-EEM,which indicated that RBK5 was degraded in the system.