【作者】 张继红；

【导师】 李亚男； 宋正光；

【作者基本信息】 太原理工大学 ， 建筑与土木工程（专业学位）， 2021， 硕士

【摘要】 含氮杂环化合物（NHCs）具有覆盖面广,生物毒性高,可生化性低等特点,其不易被降解的特性对水环境和人类的发展都有严重的危害。目前,针对NHCs的降解技术普遍存在对反应条件要求苛刻、氧化降解不完全和成本高等问题。化学氧化法因其较广的处理范围,降解速度快且效果较好,在降解有毒难降解有机物方面具有一定的优势。本文利用高铁酸钾（Fe（Ⅵ））的强氧化性、绿色无毒等优点,选取吲哚、喹啉和吡啶作为NHCs的典型代表,采用高效液相色谱检测、Fe（Ⅱ）和Fe（Ⅲ）浓度检测、羟基自由基捕获和气相色谱测定等方法,确定Fe（Ⅵ）氧化降解吲哚、喹啉和吡啶的最佳反应条件,建立动力学模型,识别氧化产物,推测反应路径,探明Fe（Ⅵ）及联用工艺氧化吲哚、喹啉和吡啶的反应机理。并考察Fe（Ⅵ）对模拟焦化废水中吲哚、喹啉和吡啶的氧化降解效果,为实际废水中NHCs的氧化去除提供理论依据。主要研究结论如下:（1）Fe（Ⅵ）氧化降解吲哚的最佳条件是pH=7,温度为25℃,Fe（Ⅵ）和吲哚的质量比为15。在此条件下,吲哚的去除率在15 min内达到了77.91%。前7 s为Fe（Ⅵ）降解吲哚的快速反应阶段,吲哚的降解速率符合准一级反应动力学模型,其反应速率常数为0.13468 s^-1。Fe（Ⅵ）对吲哚的总降解包括氧原子的转移,脱羟基,羟基的加成和氧化。（2）序批投加Fe（Ⅵ）以及Fe（Ⅵ）/H₂O₂联用均能有效提高吲哚的去除率。其中,当投加次数为5次时,吲哚的去除率由一次性投加时的77.91%提高到92.9%;Fe（Ⅵ）与H₂O₂物质的量比为1:5投加时,吲哚的去除率提高到87.3%。（3）Fe（Ⅵ）对喹啉的降解主要发生在前1s内,该反应在10 min内基本完成。在温度为25℃,pH为5,喹啉与Fe（Ⅵ）的物质的量比为1:5的条件下,喹啉的去除率达到81.16%。Fe（Ⅵ）对喹啉的总降解包括氧原子的转移,脱羟基,苯环的加成,羟基的加成和氧化,最终形成α-己基肉桂醛,紫苏醛和二氢香芹醇。序批投加Fe（Ⅵ）能有效提高喹啉的去除率,当投加次数为4次时,喹啉的去除率由一次性投加时的81.16%提高到96.12%。（4）Fe（Ⅵ）氧化降解吡啶在5 min内基本完成,在温度为25℃,pH为7,吡啶与Fe（Ⅵ）的物质的量比为1:3的条件下,吡啶的去除率达到了36.89%。Fe（Ⅵ）对吡啶的总降解包括吡啶羟基化,裂解NC键,以及羟基的进一步氧化,最终形成2,3-二甲基戊醛和2-甲基戊酮。序批投加Fe（Ⅵ）4次时,吡啶的去除率提高到43.0%;但Fe（Ⅵ）/H₂O₂,Fe（Ⅵ）/过硫酸盐联合工艺均没有提高吡啶的去除率。（5）焦化废水中可溶性物质可能影响了Fe（Ⅵ）对吲哚、喹啉和吡啶的氧化降解,但Fe（Ⅵ）对NHCs的去除仍具有较高的选择性。更多还原

【Abstract】 Nitrogen heterocyclic compounds（NHCs）have the characteristics of wide coverage,high biological toxicity,and low biodegradability.Because of the high chemical stability,the NHCs were hard to be degraded in wastewater,causing serious harm to water and humans.At present,the degradation technologies for NHCs have problems such as harsh reaction conditions,incomplete oxidative degradation and high cost,etc.The chemical oxidation method has advantages in degrading toxic and refractory organics due to its wide processing range,fast degradation speed.In this paper,indole,quinoline and pyridine were selected as typical representatives of NHCs.High-performance liquid chromatography detection,Fe（Ⅱ）and Fe（Ⅲ）concentration detection,capture of hydroxyl radicals and gas chromatography measurement methods were used.The optimal reaction conditions for Fe（Ⅵ）oxidative degradation of indole,quinoline and pyridine were determined,a dynamic model was established,the oxidation products were identified,and the reaction pathways were speculated to find out the reaction mechanism of Fe（Ⅵ）and the combined process to oxidize indole,quinoline and pyridine.The effect of Fe（Ⅵ）on the oxidation of indole,quinoline and pyridine in simulated coking wastewater was investigated,to provide a theoretical basis for the oxidative removal of NHCs in actual wastewater.The main research conclusions were as follows:（1）The optimal condition for oxidation of indole by the pH was 7,the temperature was 25℃,Fe（Ⅵ）was that the mass ratio of Fe（Ⅵ）to indole was 15,and in this condition,the removal rate of indole reached 77.91%within 15minutes.The first 7s of Fe（Ⅵ）degradation of indole was the rapid response stage,and the degradation rate of indole conformed to the quasi-first order reaction kinetic model.The rate constants of the reaction were 0.13468 s^-1under neutral conditions.The degradation pathways of indole by Fe（Ⅵ）included the transfer of oxygen atoms,dehydroxylation,addition and oxidation of hydroxyl groups.（2）Sequential batch addition of Fe（Ⅵ）and Fe（Ⅵ）/H₂O₂could effectively improve the removal rate of indole.When the number of dosing was 5 times,the removal rate of indole increased from 77.91%to 92.9,while the removal rate indole was 87.3%when the ratio of Fe（Ⅵ）to H₂O₂was 1:5 dosing.（3）The degradation of quinoline by Fe（Ⅵ）mainly occurred in the first 1s.The reaction was basically completed within 10 minutes.At a temperature of25℃,a pH of 5,and a ratio of quinoline to Fe（Ⅵ）of 1:5,the removal rate of quinoline reached 81.16%.Sequential batch addition of Fe（Ⅵ）could effectively improve the removal rate of quinoline.When the number of dosing was 4 times,the removal rate of indole increased from 81.16%to 96.12%.The degradation pathways of quinoline by Fe（Ⅵ）included the transfer of oxygen atoms,dehydroxylation,addition of benzene rings,addition and oxidation of hydroxyl groups.The final products wereα-hexylcinnamaldehyde,perillaldehyde and dihydrocarvol.（4）The Fe（Ⅵ）oxidative degradation of pyridine was basically completed within 5 minutes.Under the conditions of a temperature of 25℃,a pH of 7,and a ratio of pyridine to Fe（Ⅵ）of 1:3,the removal rate of pyridine reached 36.89%.Sequential batch dosing of Fe（Ⅵ）for 4 times,the removal rate of pyridine increased to 43.0%.However,the Fe（Ⅵ）/H₂O₂,Fe（Ⅵ）/persulfate combined process did not help to increase the removal rate of pyridine.The degradation pathways of pyridine by Fe（Ⅵ）included pyridine hydroxylation,cleavage of NC bonds,and further oxidation of hydroxyl groups.Finally,2,3-dimethylpentanal and 2-methylpentanone were formed.（5）Soluble organic matter in coking wastewater may affect the oxidative degradation of indole,quinoline and pyridine by Fe（Ⅵ）,but Fe（Ⅵ）still has a high selectivity for the removal of NHCs.更多还原