高级氧化法降解对硝基苯酚的工艺与机理研究

发布时间：2018-04-02 09:22

  本文选题：超声电化学　切入点：高锰酸钾　出处：《华南理工大学》2016年硕士论文

【摘要】：酚类化合物属于难降解有机物,广泛存在于各行各业,特别是随着工业的发展,水体中的酚类污染物越来越多。由于低含量的酚类物质即可造成生物体中毒,近年来酚类物质的降解也受到越来越多的关注。其中较普遍应用的就是超声电化学法和高级氧化法。本论文主要开展了以下几点研究:在已有实验工作基础上进一步探究了单独脉冲超声、单独脉冲电化学、连续超声电化学、脉冲超声电化学工艺降解对硝基苯酚的效果,分析了后三种工艺的反应机理和反应动力学,并通过对脉冲超声电化学工艺的反应总有机碳和能耗的探索,分析了其实际工业操作中的可行性。研究结果表明,最佳反应条件脉冲超声电化学工艺在2 h时处理对硝基苯酚的效率达到94.1%,高于连续超声电化学的89.0%和脉冲电化学的58.9%,其降解情况符合一级动力学模型,但降解2 h时溶液中总有机碳量基本保持不变,经济效应分析该种方法在工业上实施难度较大且不能完全去除污染物。本研究采用高锰酸钾处理对硝基苯酚溶液这一更加经济高效的水处理方法,研究了反应温度、pH、最佳投加量、对硝基苯酚初始浓度和总有机碳去除情况。通过对反应过程中生成的二氧化锰MnO2-1与实验室由高锰酸钾和水合硫酸锰制备的二氧化锰MnO2-2进行FTIR、BET和XRD表征对比分析,解释了反应中原位生成的MnO2-1可能的作用。实验对高锰酸钾降解对硝基苯酚的作用机理进行了TOC、GC-MS和LC-MS分析,推断了中间产物。研究结果表明,在实验条件初始pH=2.0,高锰酸钾与对硝基苯酚摩尔比K-P=10,温度T=40℃,对硝基苯酚初始浓度200 mg/L的条件下反应5 min PNP降解率达99%以上,原位生成的二氧化锰吸附和氧化作用较小可忽略不计。该工艺条件同时适用于低浓度和高浓度的对硝基苯酚溶液。降解过程中生成了大量对硝基苯酚二聚体、2,4-二硝基苯酚、对硝基邻苯二酚、硝基苯、苯酚、马来酸等中间化合物,在反应进行1 h时总有机碳的去除率达到97.9%,确立了一种高效、经济合理的有机物处理方法。
[Abstract]:Phenolic compounds are difficult to degrade organic compounds and widely exist in various industries, especially with the development of industry, more and more phenolic pollutants in water. In recent years, more and more attention has been paid to the degradation of phenols, among which ultrasonic electrochemical method and advanced oxidation method have been widely used. One step to explore the single pulsed ultrasound, The effect of pulse electrochemistry, continuous ultrasonic electrochemistry and pulse ultrasonic electrochemistry on the degradation of p-nitrophenol was studied. The reaction mechanism and kinetics of the latter three processes were analyzed. By exploring the total organic carbon and energy consumption of pulsed ultrasonic electrochemical process, the feasibility of its practical industrial operation is analyzed. The results show that, The optimum reaction conditions were as follows: the treatment efficiency of p-nitrophenol reached 94.1 at 2 h, which was higher than that of continuous ultrasonic electrochemistry (89.0%) and pulse electrochemistry (58.9%). The degradation of p-nitrophenol was in accordance with the first-order kinetic model. However, the total organic carbon content in the solution remained basically unchanged after 2 h degradation. This method is difficult to implement in industry and can not completely remove pollutants. In this study, potassium permanganate was used to treat p-nitrophenol solution, which is a more economical and efficient water treatment method. The pH of the reaction and the optimum dosage were studied. The initial concentration of p-nitrophenol and the removal of total organic carbon. The manganese dioxide MnO2-1 produced in the reaction process and the manganese dioxide MnO2-2 prepared by potassium permanganate and manganese sulfate hydrate in laboratory were characterized by FTIR BET and XRD. The mechanism of degradation of p-nitrophenol by potassium permanganate was analyzed by TOCX GC-MS and LC-MS, and the intermediate product was inferred. Under the conditions of initial pH 2.0, molar ratio of potassium permanganate to p-nitrophenol 10, temperature 40 鈩，

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