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采用266nm激光闪光光解瞬态吸收光谱和254nm紫外光降解,研究了乙腈及乙腈-水混合溶液中4-n-壬基酚(4-n-NP)的各种光解行为,考察了不同物理化学体系对4-n-NP光解行为的影响规律.实验发现,在266nm激光闪光光解下,4-n-NP既发生光电离又发生光激发,获得了4-n-NP光电离生成的阳离子自由基,以及光激发生成的激发三重态的瞬态特征吸收谱.由S2O82-光分解产生的SO4·-可快速氧化4-n-NP,测得反应速率常数为2.85×109M-1s-1,判定4-n-NP阳离子自由基在pH高于2.2条件下会转变成脱质子中性自由基.研究发现,使用254nm紫外光直接降解4-n-NP比较困难,UV结合添加H2O2可提高其降解效率,UV结合添加K2S2O8可极大提高4-n-NP降解效率,3.5min的光照即可使1×10-4M的4-n-NP完全降解.本文就4-n-NP在各种条件下的光解机理进行了探讨,为此类具有生物激素效应的非离子表面活性剂光降解奠定了基础.
The photolysis behavior of 4-n-nonylphenol (4-n-NP) in acetonitrile and acetonitrile-water mixtures was investigated by using 266 nm laser photolysis transient absorption spectroscopy and 254 nm UV degradation. NPs on the photolysis behavior of 4-n-NP. The experimental results showed that 4-n-NP photoionization and photoexcitation occurred under 266nm laser flash photolysis. 4-n-NP photoionization Generated cationic free radicals and the transient characteristic absorption spectra of the excited triplet states generated by photoexcitation.The SO 4 · - generated by S2O82-photodecomposition oxidized 4-n-NP rapidly and the reaction rate constant was 2.85 × 109 M- 1s-1, it was determined that 4-n-NP cation radical would change to deproton-neutral radical when the pH was higher than 2.2. It was found that using 254nm UV light to directly degrade 4-n-NP was more difficult. UV- H 2 O 2 could improve the degradation efficiency of 4-n-NP, and the combination of UV and K2S2O8 could greatly improve the degradation efficiency of 4-n-NP, and 4-n-NP of 1 × 10-4M could be completely degraded by 3.5min light irradiation.In this paper, Photolysis mechanism of NP under various conditions was discussed, and laid the foundation for the photodegradation of such nonionic surfactants with bio-hormone effect.