通过室内模拟实验,采用125W高压汞灯作为光源,在低温条件下(-14~-12℃)研究了冰相中硝酸根存在下苯酚的光解.考察了苯酚的浓度、硝酸根的浓度、pH值以及光强度等因素对冰相中苯酚光化学转化的影响.研究结果表明,在冰相中苯酚光转化速率随着光强度和NO3^-初始浓度的增加而加快,随着苯酚初始浓度的增加而减慢;在强酸或强碱条件下均抑制苯酚的光转化速率;苯酚的光解速率符合一级动力学模式.利用GC-MS和LC-MS分析了苯酚的光解产物,据此推测了苯酚在硝酸根体系中可能的光解反应历程.
The photolysis of nitrate ion ( NO3^- ) is widely studied in water. The formation of mutagens by photochemical reaction of aromatic compounds in aqueous solution was also observed and attributed to a photochemical nitration. While NO3^- is one of the dominating anions found in ice samples in both polar regions, the photolysis of NO3^- in ice is still an unknown field. Hence, the aim of this paper is to determine the kinetics and pathways of phenol photoconversion induced by NO3^- in ice. Using 125 W high-pressure mercury lamp as light source, under the condition of low temperature ( - 14- - 12 ℃), the ice photoconversion reaction of phenol was studied when NO3^- existed in ice. Each factor on phenol photoconversion in ice and phenol photo-conversion dynamics were inspected. The results showed that initial concentration of phenol, initial concentration of NO3^-, pH value and light strength all had greater influence on phenol photoconversion in ice. The photoconversion rate of phenol increases rapidly with the increasing of the initial concentration of NO3^- and light intensity, and decreases with the increasing of the initial concentration of phenol. Under the strong acid or alkali were decreased the photoconversion rate of phenol. The photoconversion of phenol follows first-order kinetics equation. The photoproducts of phenol photolysis in ice were analyzed by GC-MS and LC-MS and on this basis the photoconversion mechanism of phenol was proposed.