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化学学报
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化学学报 ›› 2012, Vol. 70 ›› Issue (17): 1819-1826.DOI: 10.6023/A12060320 上一篇    下一篇

研究论文

水体中壬基酚光降解机理研究

李艳霞, 段晓勇, 李先国, 唐旭利   

  1. 中国海洋大学海洋化学理论与工程技术教育部重点实验室 青岛 266100
  • 投稿日期:2012-06-18 发布日期:2012-07-25
  • 通讯作者: 李先国
  • 基金资助:
    项目受国家自然科学基金(No. 40976041)资助.

Mechanism Study on Photodegradation of Nonylphenol in Water by Intermediate Products Analysis

Li Yanxia, Duan Xiaoyong, Li Xianguo, Tang Xuli   

  1. Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
  • Received:2012-06-18 Published:2012-07-25
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 40976041).

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在模拟太阳光条件下, 通过测定光解过程中壬基酚(NP)残留率和中间产物, 考察了溶解氧(DO), H2O2, NO3-及Cl-对水体中NP光解的影响, 并推测了降解途径. 结果表明: DO浓度越低NP降解越慢, 产物有4-壬基-邻苯二酚、壬醇、壬醛和壬酸, 其中以壬酸为主, 推测NP在 O2·-作用下, 生成邻酚, 再发生共轭加成. H2O2, NO3-的添加显著加快NP降解速率, 产物有碳链缩短(2～8碳)的酚、4-壬基-邻苯二酚、壬醇、壬醛、壬酸, 其中以壬醛为主, H2O2, NO3-在光照下生成·OH, ·OH进攻NP电子云较集中的位置, NO3-吸收光同时产生·NO2, 检测到2-硝基-4-壬基酚. 在H2O2存在下, Cl-的添加对NP降解先促进后抑制, 并检测到壬酰氯, 推测·OH与Cl-共存, 形成Cl2-参与反应, 氯代产物的前驱体可能是壬醛.

关键词: 壬基酚, 光降解, 溶解氧, 过氧化氢, 硝酸根, 氯离子

The photodegradation mechanisms of nonylphenol (NP) with the involvement of dissolved oxygen (DO), hydrogen peroxide, nitrate ion and chloride ion in water by simulated sunlight were studied, respectively. The influence of each factor on the photodegradation of NP has been assessed through contrasting the residual rate of NP. And the photodegradation pathways in different conditions have been proposed according to the intermediate products identified by GC-MS. DO was a key factor in the photodegradation of NP and the rate of photoreaction depended on O2 concentration; the existence of H2O2 or NO3- increased the NP degradation rate significantly; with the existence of H2O2, the addition of Cl- first accelerated then slowed down the NP degradation rate. When NP reacted with DO, 4-nonylcatechol, nonanol, nonanal and nonoic acid have been identified as the degradation products. The accumulated amount of nonoic acid was the most. The proposed mechanism was that the 4-nonylcatechol and ortho-quinone derivative were produced after the formation of 4-nonylphenoxyl radical and superoxide radical anions (O2·-), then the intermediates underwent conjugate addition, nonanol, nonanal and nonoic acid were produced. In the presence of H2O2, 4-n-akylphenol (HOC6H4-CnH2n+1, n＝2～8), 4-nonylcatechol, nonanol, nonanal and nonoic acid were the degradation products. And the accumulated amount of nonanal was the most. The hydroxyl radicals (·OH) generated by the photolysis of H2O2 attacked the electronic gathered positions of NP molecules. The products detected in the presence of NO3- were same as which detected in the presence of H2O2. The irradiated NO3- can produce ·OH and ·NO2, so 2-nitryl-4-nonylphenol was found as the product of ·NO2 attacking the ortho-position of phenolic hydroxyl. In the presence of Cl- and H2O2, the nonanoyl chloride was found. The accumulated amount of nonanal was the most, so the probable mechanism was that the chlorine radical which generated from the reaction of ·OH and Cl- reacted with nonanal.

Key words: nonylphenol, photodegradation, dissolved oxygen, hydrogen peroxide, nitrate ion, chloride ion