偶氮染料的光汗协同降解及其生成芳香胺的测定

以活性艳红X-3B为目标染料,选择AATCC标准人工汗液在光照条件下进行偶氮染料的降解反应.通过测定降解过程中紫外-可见吸收光谱的变化,表征了光汗协同对偶氮染料降解过程的影响.结果表明,光照与汗液对偶氮染料的降解脱色具有明显的协同作用.汗液中有机组分对偶氮染料的光汗协同降解起主要作用,但汗液中的无机盐组分对偶氮染料的降解脱色有一定的抑制作用.在相同辐照时间下,染料的降解脱色率随辐照强度的增加而增加,光强为2.68 mW/cm~2辐照240 min时,模拟水样中活性艳红X-3B的降解脱色率达35%以上.光汗协同降解反应过程中-lnA_t/A_0与t的关系符合一级动力学方程;反应的速率常数随光强的增加而增大.通过采用纤维膜保护液相微萃取和毛细管电泳联用的方法,实现了活性艳红X-3B光汗协同降解过程中生成苯胺的测定.

Synergistic degradation of azo dyes by photo-perspiration and the determination of the degradation formation aniline

The paper intends to introduce a reaction process we have studied by using UV-VIS spectrum and a method we have developed known as hollow-fiber protected liquid-phase micro-extraction for capillary electrophoresis for analyzing the degradation. For our research purpose, we have carried out degradation experiments of the reactive brilliant X-3B by using photo-perspiration based on the AATCC standard system. The results of our investigation and analysis show that human perspiration and light tend to have synergistic effects on the degradation reaction of azo dyes. In fact, the organic components of perspiration prove to have been playing the key role on the degradation of the azo dyes, while the inorganic salt of perspiration sometimes tends to decelerate the fading extent. In addition, the removal efficiency of chroma by using lactic acid or L-histidine hydrochloride can reach respectively 11.55% and 23.8% whereas the removal efficiency of lactic acid and L-histidine hydrochloride in eliminating chroma proves to be 30.1%, higher than that of AATCC standard system, which was only 19.9%. Furthermore, the reduction of azo dyes has been significantly enhanced with the increase of the irradiation. However, in the condition of ultraviolet intensity of 0.75 mW/cm~2,during the irrational time of 240 min, the removal efficiency of reactive brilliant X-3B tends to be just 16.18%. Nevertheless, if the ultraviolet intensity were just increased to 2.68 mW/cm~2,the removal efficiency would rise to 35%. Thus, the degradation process proves to follow the first kinetics law, that is, the degradation rate tends to increase constantly with the increase of ultraviolet intensity. Its respective apparent rate constant turns out 0.035 4, 0.071 3, 0.102 3 on the conditions of ultraviolet intensity of 0.75 mW/cm~2, 0.69 mW/cm~2, 2.68 mW/cm~2. As the same time, hollow-fiber protected liquid-phase micro-extraction could be coupled with on-line back-extraction field-amplified sample injection in helping to determine the aniline release from the degradation of reactive brilliant X-3B. So far, the method has already been applied to the standard sampling of aniline (1.0 μg/mL), with its limit of detection (LOD) approaching 0.005 μg/mL, relative standard deviation 4.8% (n=6), and the enrichment multiple 280. Thus, the degradation reaction of azo dyes by photo-perspiration proves to be a photoreduction reaction, with its concentration of aniline in azo dyes solution being 0.064 μg/mL after 240 min reaction.