Fenton氧化降解苯胺的条件优化及机理研究

发布时间：2018-03-10 10:21

本文选题：Fenton　切入点：难降解有机物　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：苯胺是一种高毒性、不易生物降解的有机污染物,如何治理苯胺废水已成为当务之急。国内外相关研究动态表明Fenton技术具有氧化性强、反应条件简单、操作方便、不易产生二次污染物等特点,在处理难降解有机污染物时具有独特的优势。为了提高Fenton氧化效果应该确定最佳反应条件。Fenton反应的本质是氧化还原反应,而氧化还原电位(ORP)作为氧化还原反应的重要参数,理论上能够较好的指示Fenton反应进程。因此,系统地分析Fenton反应影响因素作用机制,、实现Fenton技术的在线控制有着重要指导意义。通过考察p H、H2O2/Fe2+的摩尔投加比以及绝对投加量等因素对Fenton氧化降解苯胺的影响,通过正交试验优化Fenton氧化条件;再根据不同条件下反应过程中ORP及其峰值的变化,筛选出Fenton反应体系的主要氧化还原电对,对Fenton氧化苯胺过程中氧化还原电位的变化规律进行研究,以达到通过ORP表观值控制Fenton反应进程的目的;通过检测Fenton降解苯胺的中间产物对其反应机理进行初步的研究和探讨。主要研究结果如下:(1)利用Fenton试剂处理浓度为100mg/L的模拟苯胺废水,通过单因素及正交试验得出其最优操作条件为:p H=3.3,H2O2/Fe2+投加摩尔比为10:1,H2O2和Fe2+的绝对投加量分别为12.5mmol/L及1.25mmol/L;在该条件下反应60min,苯胺和CODcr的去除率即可分别达到87.73%和67.12%。(2)氧化还原电对Fe3+/Fe2+直接决定Fenton反应过程中的ORP值,p H值、H2O2投加量和H2O2/Fe2+投加摩尔比等因素均可影响体系中铁离子形态转化,其中H2O2投加量的影响最为显著;根据Fenton反应过程中,ORP的变化规律指示有机物的降解程度。(3)借助气-质联用仪(GC-MS)分析检测了苯胺降解的中间产物,对苯胺的降解机理进行了初步探讨。苯胺降解的初始产物主要为氨基苯酚,随着反应的进行,苯环开环生成丁烯二酸。这一反应与羟基化经典理论相符。在Fenton试剂足够的条件下,丁烯二酸再同羟基自由基发生进一步反应,并最终转化为二氧化碳和水。
[Abstract]:Aniline is a highly toxic and not biodegradable organic pollutant. How to treat aniline wastewater has become an urgent matter. The related research trends at home and abroad show that Fenton technology has strong oxidation, simple reaction conditions and convenient operation. In order to improve the oxidation effect of Fenton, it should be determined that the best reaction condition is redox reaction. As an important parameter of redox reaction, redox potential can indicate the process of Fenton reaction in theory. It is important to analyze the mechanism of influencing factors of Fenton reaction and realize the on-line control of Fenton technology. The effects of molar ratio of p H 2O 2 / Fe 2 and absolute dosage on the oxidation and degradation of aniline by Fenton are investigated. The oxidation conditions of Fenton were optimized by orthogonal test, and the main redox electric pairs of Fenton reaction system were selected according to the change of ORP and its peak value during the reaction under different conditions. The change of redox potential in the process of aniline oxidation by Fenton was studied in order to control the process of Fenton reaction through the apparent value of ORP. The reaction mechanism of aniline was studied by detecting the intermediate product of aniline degradation by Fenton. The main results are as follows: 1) the simulated aniline wastewater with 100 mg / L aniline concentration was treated with Fenton reagent. By single factor and orthogonal test, the optimal operating conditions were obtained as follows: molar ratio of 10: 1: 1% H _ 2O _ 2 and Fe2 were 12.5 mmol / L and 1.25 mmol / L, respectively, and the removal rates of aniline and CODcr reached 87.73% and 67.12.1 mmol / L for 60 mins respectively (P < 0.05). The optimum conditions for oxidation of aniline and CODcr were as follows: the molar ratio of H _ 2O _ 2 to H _ 2O _ 2 was 10: 1 / 1 and the absolute dosages of H _ 2O _ 2 and Fe2 were 12.5 mmol / L and 1.25 mmol / L, respectively. Fe3 / Fe _ 2 directly determines the amount of H _ 2O _ 2 and H _ 2O _ 2 and the molar ratio of H _ 2O _ 2 / Fe _ 2 to Fe3 / Fe _ 2 in the Fenton reaction, which can affect the transformation of Fe ~ (2 +) in the system. The effect of H _ 2O _ 2 dosage on the degradation of aniline was the most significant, and the degradation degree of organic matter was indicated according to the variation rule of Fenton. The intermediate product of aniline degradation was detected by GC-MS. The degradation mechanism of aniline was preliminarily discussed. The primary product of aniline degradation was aminophenol. This reaction is consistent with the classical theory of hydroxylation. Under sufficient conditions of Fenton reagent, butene diacid reacts further with hydroxyl radical and is converted to carbon dioxide and water.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703.1

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