172nm真空紫外辐射降解水相有机染料的机理研究

研究了氙准分子灯的172nm真空紫外辐射对水相有机染料枣红的分解机理.氙准分子灯为平面状结构,反应溶液作为灯的一端电极直接与灯表面接触.分别在枣红溶液中通入氧气和氮气以及加入KCl,以具体确定172nm辐射对枣红分子的降解是通过直接光分解还是自由基起作用.研究结果表明,在枣红的降解过程中,直接光分解起主要作用,光降解过程符合准一级动力学反应,光量子产率为6 8×10 - 3mol·eistein- 1 .在HO·、HO2 ·和O2 ·- 自由基作用下,枣红的降解在10min后偏离了准一级反应.枣红降解效率达到约80 %后,COD去除率开始增大.GC MS分析表明,在光分解和热氧化作用下,枣红分子在降解过程中形成了许多小分子碎片.

Degradation mechanism of organic dye in water by 172nm vacuum-UV radiation

The degradation mechanism of organic dye claret in water was investigated by 172nm vacuum-UV (VUV) radiation emitted from the planar Xe-excimer lamp. The solution was served as one of the electrodes of the lamp. The dye solution was respectively saturated with pure oxygen and nitrogen, and KCl was added as hydroxyl radical scavenger. It was found that direct photolysis played a main role in the degradation process of claret dye. The degradation by direct photolysis was observed the pseudo-first-order kinetics in the whole degradation process while the degradation by HO^·,HO₂^· and O₂^·- radicals deviated from first-order kinetics after 10min. The quantum yield of claret dye by direct photolysis was 6.8×10^-3 mol·eistein^-1. After the degradation efficiency had got to 80%, the rate of COD removal began to increase significantly. Some organic by-products were identified by GC/MS spectrometry as a result of photolysis and oxidation production of claret dye.