不同溶剂和光源下六溴苯的光降解研究

Study on photodegradation of hexabromobenzene under different solvents and light sources

利用气相色谱仪GC、气相色谱-质谱联用仪GC-MS研究了替代型阻燃剂六溴苯在不同溶剂、不同光源下的光降解动力学及降解途径。结果表明,六溴苯的吸收光谱为210~280 nm,在260 nm处达到了最大吸收波长。在初始浓度、光源条件一定的条件下,六溴苯的光降解符合一级动力学方程。同一光源和同一浓度下,六溴苯的光降解速率为正己烷>甲苯;在溶剂浓度相同、不同光源下,六溴苯的降解速率为500 W金卤灯>500 W汞灯>300 W汞灯>500 W氙灯;六溴苯的降解途径为逐步脱溴过程,降解产物主要是低溴代的五溴苯、四溴苯、三溴苯等。

The photodegradation kinetic and degradation pathway of substituted flame retardant hexabromobenzene under different solvents and different light sources were studied by gas chromatography（ GC） and gas chromatography-mass spectrometry（ GC-MS）. The results show that the absorption spectrum of hexabromobenzene is 210-280 nm and the maximum absorption wavelength is reached at 260 nm. Under certain initial concentration and light source, the photodegradation of hexabromobenzene accords with the first-order kinetic equation. The photodegradation rate of hexabromobenzene in n-hexane is faster than that in toluene under the same concentration and light source. Under the same solvent concentration and different light sources, the degradation rate of hexabromobenzene is 500 W metal halide lamp 〉 500 W mercury lamp 〉300 W mercury lamp〉 500 W xenon lamp. The degradation pathway of hexabromobenzene is gradual debromination process. The degradation products are mainly lower bromine generation benzenes, such as pentabromobenzene, tetrabromobenzene, tribromobenzene, etc..