氯酚光催化降解毒性中间产物生成阻断动态研究及其机制探讨

Chlorophenols is a class of persistent organic pollutants, which can lead to biological variation at very low concentration. To date, photocatalytic oxidation method is one of the most prospective technologies for degradation of these pollutants, in which, how to block the generation of high toxic intermediate products is the key for the control of environmental pollutants and it is still very hot and difficult. Based on these, the project intends to construct bioinorganic nanohybrids to block the generation of toxic intermediates during the photocatalytic degradation of chlorophenols. The key reactive oxygen species involved the transfomation of toxic intermediates was firstly studied and determined. On this basis, the generation type of ROS were regulated and controlled through synthesis of the bioinorganic nano-TiO2, which can block or inhibit the generation of high toxic intermediates during the photocatalytic degradation process. Furthermore, chemiluminescence spectroscopy, fluorescence spectroscopy, X-ray diffraction, electron spin resonance spectroscopy, high performance liquid chromatography -mass spectrometry technologies and luminescent bacteria toxicity test etc were used to verify and characterize the block of toxic intermediates, explore the intrinsic relationship between ROS generation, electron transfer and its interaction with the toxic intermediates, reveal the dynamic blocking mechanism for the generation of toxic intermediates, which can lay the theory foundation for its application in the field of environmental science and analytical chemistry.

氯酚是一类难降解有机污染物，超痕量暴露就会引起生物变异。针对这类污染物去除研究最活跃的是光催化氧化技术，催化降解高毒性中间产物的生成阻断是研究的难点和关键。基于此，申请者拟开展生物/无机纳米粒子参与氯酚光催化降解毒性中间产物的生成阻断研究。利用化学发光研究毒性中间产物动态转化的关键活性氧作用类型，构建各种生物/无机功能化TiO2纳米粒子，调控体系中活性氧的动态产生，阻断毒性中间产物的动态生成。采用化学发光光谱、紫外可见吸收光谱、荧光光谱、电子自旋共振、高效液相色谱-质谱、发光菌毒性测试等手段，对降解反应毒性中间产物的动态阻断进行验证和表征，探讨活性氧自由基动态生成消失、电子转移过程和氯酚降解毒性中间产物相互作用的内在联系，揭示氯酚光催化降解毒性中间产物的动态阻断机制和规律，为其在环境化学和分析化学领域中的应用研究奠定理论基础。

五氯酚是一类难降解有机污染物，超痕量暴露就会引起生物变异。针对这类污染物去除研究最活跃的是光催化氧化技术，催化降解中高毒性中间产物的生成阻断是研究的难点和关键。基于此，本项目构建了多巴胺/二氧化钛（PDA/TiO2）生物无机纳米粒子参与氯酚光催化降解过程，实现了五氯酚光催化降解毒性中间产物三氯苯醌（OH-TrCBQ）和四氯苯醌（TCBQ）的生成阻断。首先利用化学发光研究五氯酚光催化降解活性氧和毒性中间体的动态变化，确定了毒性中间体三氯苯醌和四氯苯醌生成转化的关键活性氧作用类型是超氧自由基和过氧化氢；在此基础上，合成了PDA/P25生物-无机纳米材料，通过PDA表面改性P25，调控P25表面活性氧自由基产生的种类和数量。研究发现PDA修饰P25后，PDA作为空穴猝灭剂能够抑制电子空穴复合，促进光生电子的生成，进而引起超氧自由基和H2O2增多，促进毒性中间产物TCBQ和OH-TrCBQ的降解；利用连续流化学发光法，动态检测了光催化降解PCP过程中产生的毒性中间产物四氯-1,4-苯醌和三氯苯醌，结果显示P25/PDA复合材料表面产生大量H2O2(约30 μM）和O2•-(约20 μM）来抑制大约70% TCBQ和40% OH-TrCBQ的产生；最后，利用化学发光光谱、紫外可见吸收光谱、荧光光谱、高效液相色谱-质谱、发光菌毒性测试等手段，对降解反应毒性中间产物的生成阻断进行验证和表征，探讨了活性氧自由基生成、电子转移过程和五氯酚降解毒性中间体相互作用的内在联系，揭示了五氯酚光催化降解毒性中间产物的动态阻断机制，为其在环境污染控制领域中的应用研究奠定理论基础。