联合多种荧光光谱和GC-MS研究高铁酸钾对菲的降解机理

Degradation of phenanthrene by potassium ferrate(Ⅵ)characterized by fluorescence and GC-MS

研究了高铁酸钾对PAHs中的菲的降解反应过程,对该反应过程联合了时间扫描、偏振、偏振三维(PEEM)、三维(EEM)等多种荧光光谱模式进行了表征和分析,并结合GC-MS进一步检测分析了该反应过程的中间产物,最后系统探讨了高铁酸钾对菲降解的动力学反应规律及降解机理.实验结果表明,在设定的高铁酸钾-菲降解体系的物质的量之比为1∶1、1∶2、1∶3、2∶1、3∶1的各个降解反应过程均符合一级反应动力学特征,其拟合系数在0.905—0.995之间.通过不同摩尔比的高铁酸钾-菲降解过程的时间扫描荧光参数直接求得了各反应的动力学方程及曲线;菲降解过程的荧光偏振度值与PEEM共同揭示出高铁酸钾对菲的有效降解,且产物均为无偏振效应、无产生新的特征荧光的小分子结构,各特征光谱峰强与时间变化关系也与时间扫描荧光曲线相符合;最后结合GC-MS深入分析了菲的降解产物,并由此推测了高铁酸钾对菲的降解机理.降解产物中9,10-菲醌的大量存在表明菲结构中9,10位发生氧化而开始降解.

In this paper, the degradation process of phenanthrene by potassium ferrate（ VI） , one of PAHs, was researched by means of multiple fluorescence modes, such as time？scan fluorescence, polarized fluorescence, and polarized excitation emission matrix（ PEEM） . Further analysis indicated the intermediate products within the phenanthrene？potassium ferrate （ VI ） degradation system through GC？MS. Finally, the phenanthrene′s degradation mechanism and kinetics were preliminarily speculated. According to the results, the phenanthrene′s degradation progress was belong to first order equation, as the mole ratios（ phenanthrene ：potassium ferrate） were 1∶1, 1∶2, 1∶3, 2∶1, 3∶1 separately. Each fitting coefficients were simply obtained through the time？scan fluorescence curves of each mole ratios degradation, and between 0. 905 and 0. 995. Polarized fluorescence degree and PEEM common revealed that phenanthrene was effectively degradated by potassium ferrate（VI）, and the degradation products included small molecular structure with no obvious fluorescent and polarized effect. Relationship of the feature fluorescence peaks with the change of time was in accord with the time？scan fluorescence′s curve. At last, phenanthrene′s degradation mechanism were speculated by combination with the intermediates analysed by GC？MS. The existence of 9, 10？phenanthrenequinone indicated that the phenanthrene began oxidation and then degradation at 9,10 in its structure.