水溶液中硝基芘的光化学反应动力学及影响因素

Photochemical kinetics and influence factors of nitropyrenes in water

通过建立降解动力学模型,对水溶液中2种硝基芘(nitropyrenes,NPs)——1-硝基芘和1,8-二硝基芘光降解过程进行了研究,考察了NPs浓度、光敏剂(H 2O 2、NO-2、NO-3)、pH值及甲醇等对NPs降解过程的影响.结果表明:2种NPs在紫外光照射下均发生了降解,且遵循一级反应动力学方程;提高1,8-二硝基芘初始浓度,其降解减慢;3种光敏剂均促进了NPs的降解;强酸和强碱条件均加速了NPs的降解,且在酸性条件下降解更快;甲醇也能促进NPs的降解,且随甲醇浓度增加NPs降解变快;此外,基于降解反应前后反应液pH值的变化,推测在NPs光解过程中可能发生了脱硝基作用.

The photochemical reaction of two nitropyrenes(NPs),1-nitropyrene(1-NP)and 1,8-dinitropyrene(1,8-DNP)in water was investigated.The photolysis kinetics of NPs was established.The effects of initial concentration of NPs,the existence of photosensitizers(hydrogen peroxide,nitrite and nitrate),pH and cosolvent methanol on the photoconversion of NPs were investigated.The results showed that NPs can be degraded by ultraviolet irradiation,and the photodegradation process obeys to the first-order reaction kinetics model.The existence of photosensitizers(hydrogen peroxide,nitrite and nitrate)promoted the photolysis of 1-NP and 1,8-DNP in varying degrees.Both strong acidity and alkalinity conditions promoted the photolysis of 1-NP and 1,8-DNP,especially in acidic conditions.The presence of cosolvent methanol promoted the photoconversion of NPs.With the increasing concentration of methanol,the photolysis of 1-NP and 1,8-DNP accelerated.Based on the change of pH value before and after photolysis,denitration process may occur during the photolysis of 1-NP and 1,8-DNP.