络合剂存在下类Fenton反应降解水中有机污染物研究

发布时间：2018-11-25 16:01

【摘要】：Fenton/类Fenton氧化法在污水预处理和深度处理中有着广泛应用。然而Fenton/类Fenton法存在应用p H较低,Fe(III)向Fe(II)转化速度慢,Fe(II)利用率低等缺点。乙二胺四乙酸(EDTA)、氨基三乙酸(NTA)与Fe3+/Fe2+形成的络合物在中性或弱碱性溶液中较稳定,保证了可溶性Fe(III)/Fe(II)浓度。杂环芳烃衍生物代表阿特拉津(AT)和苯环芳烃衍生物代表硝基苯(NB)是广泛存在于各水体中的难降解有机污染物,Fenton/类Fenton法是较理想的降解方法。本研究以EDTA、NTA为络合剂分别与AT和NB组成模拟污水,以硫酸铁溶液和H2O2组成类Fenton体系,研究不同络合剂的存在对类Fenton反应降解有机物的影响,并对Fe IIINTA/H2O2反应降解不同目标物进行研究。NTA、EDTA的存在对类Fenton反应降解AT影响实验结果:(1)络合剂存在时,在p H为7和9时,AT降解效果相对于无络合剂存在时明显提升。(2)当NTA和EDTA存在时,由于p H值的提高改变了Fe(III)络合物的形态结构,使Fe IIINTA更容易与过氧化氢络合,并且H2O2本身也更容易被分解,p H=3~9时,AT的降解效率随p H值提升而提升。(3)由于Fe IIINTA和FeIIIEDTA不同p H值下形态和空间结构差异,p H=7~9范围内,NTA存在下类Fenton反应降解AT的效果优于EDTA。(4)NTA和EDTA存在时,H2O2和Fe(III)初始浓度增加能提升AT的降解效果。(5)反应体系中叔丁醇浓度的增加对AT的降解抑制明显,这表明EDTA、NTA存在下类Fenton反应降解有机物的主要活性物种是羟基自由基。(6)Fe IIINTA和Fe IIIEDTA在降解AT的过程中自身均有分解,Fe IIIEDTA能分解成Fe IIINTA,会加快反应速率。FeIIINTA/H2O2反应降解不同结构目标物的研究表明:(1)由于NB降解中间产物的作用以及AT、NB本身结构的差异,NTA存在下,p H=3时,NB的降解效能比AT降解效能高,而p H=7时AT的降解效能更高。(2)除NTA初始浓度以外的其它因素对AT和NB的降解的影响基本相似。(3)NB降解的中间产物与无络合剂存在的类Fenton反应降解硝基苯的中间产物相同,降解途径相似。(4)NB降解中间产物对类Fenton反应自催化作用不明显,说明NTA阻碍了Fe(III)与中间产物的接触。
[Abstract]:Fenton/ type Fenton oxidation process is widely used in wastewater pretreatment and advanced treatment. However, the Fenton/ class Fenton method has some disadvantages such as low, Fe (III) conversion speed to Fe (II), low, Fe (II) utilization rate and so on. The complex formed by ethylenediamine tetraacetic acid (EDTA), aminotriacetate (NTA) and Fe3 / Fe2 is stable in neutral or weak alkaline solution, which ensures the concentration of soluble Fe (III) / Fe (II). Heterocyclic aromatic derivatives represent atrazine (AT) and benzene ring aromatic derivatives represent nitrobenzene (NB), which are widely used as refractory organic pollutants in various water bodies. Fenton/ Fenton method is an ideal method for degradation. In this study, EDTA,NTA was used as complexing agent with AT and NB to form simulated sewage, and ferric sulfate and H2O2 were used to form Fenton system to study the effect of different complexing agents on the degradation of organic compounds by Fenton reaction. The effect of NTA,EDTA on the degradation of AT by Fenton reaction was studied. The results were as follows: (1) in the presence of complex agent, pH was 7 and 9, respectively. The degradation effect of AT was significantly improved compared with that without complex agent. (2) in the presence of NTA and EDTA, the morphological structure of Fe (III) complex was changed due to the increase of pH value, which made it easier for Fe IIINTA to complex with hydrogen peroxide. The degradation efficiency of AT increased with the increase of pH value. (3) because of the difference in morphology and spatial structure of Fe IIINTA and FeIIIEDTA under different pH values, the degradation efficiency of AT increased with the increase of pH value. In the presence of NTA, the degradation of AT by Fenton reaction was better than that by EDTA. (4) NTA and EDTA. The increase of initial concentration of H2O2 and Fe (III) could enhance the degradation of AT. (5) the degradation of AT was inhibited obviously by the increase of tert-butanol concentration in the reaction system. It is suggested that the main active species for Fenton reaction degradation of organic compounds in the presence of EDTA,NTA is hydroxyl radical. (6) Fe IIINTA and Fe IIIEDTA decompose, Fe IIIEDTA to Fe IIINTA, in the process of AT degradation. The results show that: (1) due to the effect of NB on degradation of intermediate products and the structure difference of AT,NB itself, in the presence of NTA, pH = 3, The degradation efficiency of NB was higher than that of AT. The degradation efficiency of AT was higher than that of pH = 7. (2) the effect of other factors other than the initial concentration of NTA on the degradation of AT and NB was similar. (3) the intermediate product of NB degradation was similar to Fenton reaction without complexing agent to degrade nitrate. The intermediate products of benzene are the same, The degradation pathway was similar. (4) the autocatalytic effect of the intermediate product of NB degradation on Fenton reaction was not obvious, which indicated that NTA hindered the contact between Fe (III) and the intermediate product.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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