基于过硫酸盐体系的电化学发光及其在废水处理中的应用

发布时间：2018-06-05 02:16

本文选题：过硫酸盐 + 电化学发光　；参考：《西华师范大学》2016年硕士论文

【摘要】：电化学发光(ECL)是指电化学与化学发光的结合,是一种电化学诱导的原位发光行为。它涉及到电极表面高能量物质的产生,并通过电子转移反应产生发光现象。过硫酸盐(S_2O_8~(2-))是一种阴极ECL试剂,当电位为-0.6 V时,其在电极表面会发生还原反应生成SO_4~?-,SO_4~?-在水溶液中进一步的发生反应产生具有发光性的物质单线态氧,在电位-1.4~-1.8 V之间产生光辐射。除此之外,S_2O_8~(2-)还作为氧化剂被广泛的应用于污染物降解化工行业中,污染物的降解是基于S_2O_8~(2-)在反应过程中形成的中间体SO_4~?-的强氧化性,SO_4~?-能使不饱和键断裂,从而使污染物发生氧化降解。因此,活化S_2O_8~(2-)产生SO_4~?-是过硫酸高级氧化技术用于污染物处理的核心。研究已报道了多种活化S_2O_8~(2-)用于污染物降解的方法,而利用电化学诱导S_2O_8~(2-)氧化降解污染物,并应用S_2O_8~(2-)的ECL对污染物的降解进行检测的报道较少。基于此,本论文主要开展了以下工作:利用阴极电化学诱导(S_2O_8~(2-))原位生成硫酸根自由基(SO_4~?-)降解染料活性艳蓝X-BR,通过循环伏安-电化学发光(CV-ECL)的CV和ECL信号同步检测,建立反应动力学机理研究模型。通过紫外可见光谱(UV-vis)、红外光谱(IR)、气相色谱-质谱联用仪(GC-MS)对降解产物进行分析,明晰降解机理。研究结果表明,电化学诱导下,SO_4~?-通过氧化X-BR分子上的蒽醌、三嗪杂环等基团降解染料分子而使染料脱色。降解条件为:过硫酸钾溶液浓度0.1 mol·L-1,活性艳蓝X-BR浓度0.01mol·L-1,反应195 min,降解率达到最大为66.47%。降解反应符合一级反应动力学模型,反应速率常数为1.01×10-2 min-1。以小分子化合物对苯二酚(HQ)为目标污染物,利用电化学诱导S_2O_8~(2-)原位生成SO_4~?-的高级氧化技术对其氧化降解。实验中,动力学研究机理模型构建的方法与第一个工作中的一致,同时,借助于紫外可见光谱(UV-vis)、红外光谱(IR)对其降解产物进行分析。实验表明,在电化学诱导下,HQ的氧化还原峰的电流强度明显降低,对苯二酚的含量逐渐减少。降解条件为:饱和S_2O_8~(2-)溶液体积为0.8 m L,HQ的浓度为0.02 mol·L-1,p H为7.5,反应360 min,降解率达到最大为63.7%。降解反应符合一级反应动力学模型,180 min前,反应速率常数为2.4×10-3 min-1,180 min后,反应速率常数为9.5×10-4 min-1。实验采用一步电沉积法,在电极表面修饰一层金纳米(nano-Au),探讨了nano-Au对S_2O_8~(2-)发光的影响,发现nano-Au对S_2O_8~(2-)的ECL行为有明显的催化活化作用,能够促进S_2O_8~(2-)向SO_4~?-的转化。基于此,我们进一步的探讨了将nano-Au修饰在电极表面后,电化学诱导S_2O_8~(2-)对HQ降解的影响及S_2O_8~(2-)的消耗情况。研究结果显示,nano-Au在该体系中能够加速HQ的降解。降解率随着S_2O_8~(2-)加入量的增加而增加,S_2O_8~(2-)的消耗及HQ的降解反应均服从一级反应动力学模型。降解条件:饱和S_2O_8~(2-)溶液加入的体积为1.2 m L,HQ的最佳浓度为0.01 mol·L-1,p H为7.5,反应150 min,降解率达到最大为96.23%。
[Abstract]:Electrochemiluminescence (ECL) refers to the combination of electrochemistry and chemiluminescence. It is an electrochemical induced in situ luminescence. It involves the production of high energy materials on the surface of the electrode and produces luminescence by the electron transfer reaction. The persulfate (S_2O_8~ (2-)) is a cathode ECL reagent. When the potential is -0.6 V, it will appear on the surface of the electrode. The bioreduction reaction produces SO_4~? - SO_4~? - the further reaction in the aqueous solution produces luminescent material single state oxygen and produces light radiation between the potential -1.4~-1.8 V. In addition to this, S_2O_8~ (2-) is also widely used as an oxidizing agent in the industry of pollutant degradation. The degradation of pollutants is based on S_2O_8~ (2-). The strong oxidation of the intermediate SO_4~? - SO_4~? - can break the unsaturated bond and make the pollutants oxidize and degrade. Therefore, the activation of S_2O_8~ (2-) produces SO_4~? - the core of the advanced oxidation technology of sulphuric acid for the treatment of pollutants. The study has reported a variety of activated S_2O_8~ (2-) for the degradation of pollutants. Electrochemical induced S_2O_8~ (2-) oxidation degradation of pollutants, and the application of S_2O_8~ (2-) ECL to detect the degradation of pollutants is less. Based on this, this paper mainly carried out the following work: using cathode electrochemistry induced (S_2O_8~ (2-)) in situ formation of sulfate radical (SO_4~?) degradation reactive brilliant blue X-BR in the dye, through cyclic voltammetry The simultaneous detection of CV and ECL signals of electrochemiluminescence (CV-ECL) was used to establish the kinetic mechanism of reaction. The degradation products were analyzed by ultraviolet visible spectrum (UV-vis), infrared spectrum (IR) and gas chromatography-mass spectrometry (GC-MS), and the mechanism of degradation was clarifying. The results showed that the electrochemical induction, SO_4~? - through the oxidation of X-BR molecules Anthraquinone, three azine heterocyclic groups degrade dye molecules and degrade dyes. The degradation conditions are: the concentration of potassium persulfate solution is 0.1 mol. L-1, the active brilliant blue X-BR concentration is 0.01mol. L-1, the reaction is 195 min, the degradation rate reaches the maximum 66.47%. degradation reaction to the first order kinetic model, the reaction rate constant is 1.01 x 10-2 min-1. with small molecular chemistry. The compound of hydroquinone (HQ) as the target pollutant and the electrochemical induced S_2O_8~ (2-) in situ formation of SO_4~? - to oxidize it by the advanced oxidation technology. In the experiment, the method of establishing the kinetic model of the mechanism is consistent with the first work. At the same time, the degradation products are carried out with the aid of ultraviolet visible spectrum (UV-vis) and infrared spectroscopy (IR). The results show that the current intensity of the redox peak of HQ is obviously reduced and the content of hydroquinone decreases gradually under the electrochemical induction. The degradation conditions are: the volume of the saturated S_2O_8~ (2-) solution is 0.8 m L, the concentration of HQ is 0.02 mol. L-1, P H is 7.5, the reaction is 360 min, and the maximum degradation rate is in accordance with the first order reaction force for the 63.7%. degradation reaction Before 180 min, the reaction rate constant was 2.4 x 10-3 min-1180 min, and the reaction rate constant was 9.5 x 10-4 min-1. experiments using one step electrodeposition method. A layer of gold nanoparticles (nano-Au) was modified on the surface of the electrode. The effect of nano-Au on the luminescence of S_2O_8~ (2-) was investigated. It was found that nano-Au has obvious catalytic activation for ECL behavior of S_2O_8~ (2-). We can promote the transformation of S_2O_8~ (2-) to SO_4~? - based on this, we further explore the effect of nano-Au modification on the surface of the electrode and the effect of electrochemical induction of S_2O_8~ (2-) on the degradation of HQ and the consumption of S_2O_8~ (2-). The results show that nano-Au can accelerate the HQ degradation in this system. Adding and increasing, the consumption of S_2O_8~ (2-) and the degradation reaction of HQ obey the first order kinetic model. Degradation conditions: the volume of the saturated S_2O_8~ (2-) solution is 1.2 m L, the optimum concentration of HQ is 0.01 mol L-1, P H is 7.5, the reaction is 150, and the degradation rate reaches the maximum
【学位授予单位】：西华师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703;O657.1

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