【作者】 王鑫；

【导师】 秦洪伟；

【作者基本信息】 渤海大学 ， 分析化学， 2020， 硕士

【摘要】 本文研究了苯二酚异构体同步检测的电化学方法、苯二酚异构体的芬顿氧化降解以及传统芬顿氧化体系的优化,并且对实验条件、实验方法和技术手段等进行调整优化,对反应原理和降解机理进行探究验证,主要内容如下:1.三种苯二酚异构体的电化学同步检测以制备的不同修饰电极分别对苯二酚异构体进行电化学检测,选出了性能最佳的还原氧化石墨烯（rGO）修饰电极,在优化了各项检测条件后,最终实验结果表明:电极修饰材料用量为0.01 mg,以乙酸-乙酸钠缓冲液作为支持电解质,pH为5.5,富集时间300 s的条件下,rGO修饰电极可以对苯二酚异构体进行快速同步检测,并且单独检测三种苯二酚时检出限可达10^-77 mol/L,在一定浓度范围内苯二酚异构体浓度与电化学信号呈明显线性关系,并对模拟水样检测取得满意结果。2.芬顿氧化法降解三种苯二酚异构体采用传统芬顿氧化法对苯二酚异构体进行了氧化降解实验,并以所建立的电化学检测方法对降解后苯二酚浓度进行监测,实验分别探究了各条件对苯二酚异构体氧化降解的影响以及苯二酚异构体的降解机理,最终实验结果表明:芬顿试剂Fe²⁺与H₂O₂摩尔比约为5:4,投加量为9.8×10^-55 mol,氧化降解时间为45 min,pH为4.5时,对三种苯二酚异构体降解率均在85%以上。对降解后溶液进行分析,得到苯二酚共性的降解机理为:苯二酚类物质先被氧化为苯醌类物质,继而开环后形成无机酸,最终进过多次氧化后完全矿化为CO₂和H₂O。3.电还原铁促进芬顿反应降解三种苯二酚异构体通过实验构建了阳极为Ti-Ag,阴极为石墨-碳纳米管-石墨烯电极（GE-CNT-GR）的Fe³⁺电还原体系,该电还原体系在阴极电位为+0.2 V的条件下,60 min内对Fe³⁺的还原率可达52.9%。将该电还原体系与传统芬顿氧化体系结合后对苯二酚异构体进行氧化降解实验,结果表明所构建的Fe³⁺电还原体系可以有效促进芬顿反应的进行,在不影响苯二酚异构体降解效果的前提下可以减少约50%初始铁盐投加量,并且在优化条件后对三种苯二酚异构体的降解率分别可达98.20%（对苯二酚）、98.08%（邻苯二酚）和94.96%（间苯二酚）,与传统芬顿体系相比具有更好的效果。更多还原

【Abstract】 In this paper,the electrochemical methods for the simultaneous detection of hydroquinone isomers,Fenton oxidation degradation of hydroquinone isomers,and improve traditional Fenton oxidation systems are studied.In addition,the experimental conditions,experimental methods and technical means are adjusted,and the reaction principle and degradation mechanism are explored and verified.The main contents are as follows:Ⅰ.Electrochemical simultaneous detection of three hydroquinone isomersDifferent modified electrodes are prepared for electrochemical detection of hydroquinone isomers,and the reduced graphene oxide（rGO）modified electrode is selected as the best performance.After optimizing the detection conditions,the final experimental results show that the electrode modification material amount was 0.01 mg,using acetic acid-sodium acetate buffer solution as the electrolyte,pH=5.5,and preconcentration time of 300 s are the best detection conditions.The rGO modified electrode could be used for rapid and simultaneous detection of hydroquinone isomers.The detection limit for the individual detection of three types of hydroquinone is 10^-77 mol/L.Within a certain concentration range,the hydroquinone isomers concentration has a significant linear relationship with the electrochemical signal,and satisfactory results have been obtained for simulated water samples.Ⅱ.Fenton oxidative degradation of three hydroquinone isomersThe traditional Fenton oxidation method was used for the oxidative degradation of hydroquinone isomers,and the hydroquinone isomers concentration that after degradation were monitored by the established electrochemical detection method.The experiments explored the various conditions effects on the oxidative degradation of the hydroquinone isomer and the hydroquinone isomers’degradation mechanism.The final experimental results show that the molar ratio of Fe²⁺to H₂O₂ in Fenton’s reagent is about 5:4,the dosage is 9.8×10^-55 mol,the oxidative degradation time is 45 min,and the pH=4.5,the degradation rates of three hydroquinone isomers are above 85%.And the analysis of the solution after degradation shows that the hydroquinone isomers’degradation mechanism is as follows:the hydroquinone is first oxidized to benzoquinone,then the benzene ring is opened to form inorganic acids,which is finally mineralized into H₂O and CO₂ after repeated oxidation.Ⅲ.Electroreduced iron promotes Fenton oxidation of three hydroquinone isomersAn Fe³⁺electroreduction system with Ti-Ag electrode as the anode and Graphite electrode-carbon nanotube-graphene（GE-CNT-GR）as the cathode was constructed through experiments.Under the conditions that the cathode potential is+0.2V,the reduction rate of Fe³⁺can reach 52.9%within 60 minutes.The electro-reduction system was combined with traditional Fenton oxidation system to conduct oxidative degradation of hydroquinone isomers,and the results show that the Fe³⁺electroreduction system can effectively promote the Fenton reaction,and can reduce the initial iron salt dosage by about 50%without affecting the hydroquinone isomers’degradation percentage.After the optimization of the conditions,the degradation percentages of the three hydroquinone isomers are98.20%（hydroquinone）,98.08%（catechol）and 94.96%（resorcinol）,and it has better results compared to the traditional Fenton system.更多还原