电化学处理水中无机物、重金属及金属有机络合物研究
文献类型：学位论文
| 作者 | 张宝锋 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 赵旭 |
| 关键词 | 电混凝，电芬顿，砷，Cu-EDTA，工业废水 Electrocoagulation, Electro-Fenton, Arsenic, Cu-EDTA, Industrial wastewater |
| 其他题名 | Treatment of Inorganic Matters, Heavy Metals and Metal-Organic Complexs in Water by Electrochemisty |
| 学位专业 | 环境工程 |
| 中文摘要 | 电化学技术在水处理过程中日益受到重视，电混凝与电芬顿是电化学水处理技术中研究与应用较多的方法。本论文首先以氟、砷为目标物，研究电混凝对砷与氟的去除效果与过程机制；以油墨废水、煤制油废水、Cu-EDTA络合物为目标，研究阳极电芬顿处理水中有机污染物的效果、主要影响因素与影响机制，并开展了中试研究。 首先建立了组合电氧化和电混凝反应系统，将其用于去除地下水中的砷和氟污染物.反应系统内，As(III)首先被氧化为 As(V)，然后被电混凝过程产生的絮体共沉淀。电化学极板由钛钌网（DSA）和铁电极组成。As(III)氧化发生在 DSA电极表面。同时，铁电极在电感应的作用下会各种氢氧化铁化合物，这些絮体对 As(V)有较强的吸附、共沉淀作用。研究了电氧化-混凝处理 As(III)时的影响因素，发现，Ca2+和 Mg2+可以促进 As的去除；而 Cl−, CO32−, SiO32−, 和 PO43−抑制 As的去除，且 PO43−的抑制能力最强。pH=8.0时 As的去除效率最佳，过高或者过低的 pH均不利于 As的去除。利用傅里叶变换红外光谱研究电氧化-混凝处理 As的絮体，发现，絮体中 As(III)被氧化为 As(V)。 研究电絮凝同时去除水中的氟和砷污染物时，将形稳阳极与铁电极、铝电极组合，采用电感应的方法，产生铝离子及铝氧化物絮体、铁离子及铁氧化物絮体，对水中的氟离子和砷离子同时进行有效去除。考察了铁极板和铝极板的比例、电流密度、溶液 pH、共存阴阳离子等对氟离子和砷离子去除的影响，并分析了 As(III)的氧化程度，以及铁、铝的溶出对实验效果的影响。结果表明，在初始砷离子浓度为 1.0 mg/L，氟离子浓度为5.0 mg/L，电流为 120.0 mA时，铁板：铝板=1：3时可同时将溶液中的氟和砷去除，使水质达到饮用水水质标准。电混凝过程对 As(III)和 As(V)均具有较高的去除率。 针对络合态重金属污染物Cu-EDTA，开展了电芬顿氧化破络 Cu-EDTA，并通过产生的铁絮体以及铁氧化物的絮凝、吸附以及共沉淀等作用协同去除 Cu 离子及 EDTA 的实验研究。结果显示，溶液总有机碳（TOC）值随电流密度的增大、反应时间的延长而降低。当电流密度增大至 31.25 A/m2时，TOC由120.0 mg/L降至 54.7 mg/L，去除率为54.4%，继续增大电流密度至 114.58 A/m2时会降低溶液中 TOC 的去除率。电芬顿处理Cu-EDTA 时，溶液中 EDTA 的去除速率远远大于大于 TOC，电芬顿反应 5.0 分钟时，溶液中 EDTA去除率已达 99.0%。H2O2投量的增加有助于 TOC和 EDTA去除率的提高，在 H2O2投量为 98.8 mmol/L时，电芬顿反应 30 分钟后，TOC去除率达74.2%。初始pH为 3.0时TOC的去除效率最高，而pH过大或过低均不利于 TOC的去除。电芬顿反应初期•OH产量低于电芬顿反应中期，主要原因在于 Fe2+传质速率的影响。 针对油墨废水，开展了电混凝和电芬顿处理油墨废水的研究。研究发现，油墨废水中 30.0%的有机组分为悬浮性有机物，剩余 70.0%为溶解性有机物。电混凝可有效去除悬浮性有机物，但对溶解性有机物去除效率不佳；电芬顿反应 5.0 分钟有机物的去除率可达76.0%。电化学反应器中铁极板产生的Fe(II)和适量外源投加的H2O2发生芬顿反应，产生活性极高的羟基自由基（OH•），氧化降解水中的有机物，从而促进了 COD的去除。但是，外源 H2O2的过量投加，在反应初期，反而会消耗电芬顿产生的 OH•，阻碍了 COD的去除。电芬顿反应中，COD 去除率随 pH 的升高而降低，溶液中 Fe(II)的浓度取决于溶液的 pH、H2O2投量以及电流密度。利用凝胶色谱仪，紫外分光光度计，傅里叶变换红外光谱技术和三维荧光光谱技术对电混凝和电芬顿过程中有机物的组分和变化进行了研究，发现电芬顿过程中，污水中的部分芳香族有机物和大分子量有机物被氧化为脂肪烃类物质和小分子有机物。 煤制油废水广泛存在于煤制油工艺中。在实验内，使用 1.0 L 的反应器，利用阳极电芬顿与 NaClO氧化处理煤制油废水。在阳极电芬顿过程中，氧化剂 H2O2的投量为 6.0‰，COD值可从进水的5500.0 mg/L 降至出水时的 2200.0 mg/L，与此同时，NH4-N含量从530.0 mg/L升高至 550.0 mg/L，色度由反应前的 55.0升高至 1790.0，这是因为阳极电芬顿反应之后，产生的大量 Fe(II)和 Fe(III)和水中残留的有机物鳌合、络合，从而使色度急剧增加。大量的 Fe(II)和 Fe(III)的存在会阻碍后续的生化反应，因此投加 NaClO氧化剂于阳极电芬顿出水中，以破络合金属有机物。NaClO氧化工艺的最佳效果为：COD，NH4-N，色度和浊度去除率分别为 11.0%、89.0%、94.0%、98.0%。反应过程中 95 %的铁-有机物络合物被破络合，从而使 Fe(III)顺利沉淀。 |
| 英文摘要 | Environmental electrochemistry is the electrochemical theory and method applied in the field of environmental protection.Electrocoagulation and anode electric fenton electrochemical technology of environmental electrochemistry is widely used in environmental protection. In this experiment, with the target of fluorine, arsenic and chromium,the treatment effect of removal of inorganic matter and heavy metals in water by electrocoagulation and chemical reductant-electric flocculation were studied; with the target of plugboard wastewater and coal oil wastewater, the effects of removal of organic contaminant by the anode fenton technology were studied. An electrochemical reactor was built and used to remove arsenite from water. In this reactor, arsenite can be oxidized into arsenate, which was removed by electro-coagulation process simultaneously. The reactor mainly included dimension stable anode (DSA) and iron plate electrode. Thus, the arsenic was removed by coagulation process. Influencing factors on the removal of arsenite were investigated. It is found that Ca2+ and Mg2+ ions promoted the removal of arsenite. However, Cl−, CO32−, SiO32−, and PO43− ions inhibited the arsenic removal. And, it is observed that the inhibition effect was the largest in the presence of PO43−. Furthermore, it is observed that the removal efficiency of arsenate is the largest in the pH value of 8. Increase or decrease of pH value did not benefit to the arsenite removal. Fourier transform infrared spectra were used to analyze the floc particles, it is suggested that the removal mechanism of As(III) in this system seems to be oxidative of As(III) to As(V) and to be removed by adsorption/complexation with metal hydroxides generated in the process. Furthermore, in order to removal fluoride and arsenic ions simultaneously, combination of DSA electrode with aluminum electrodes and iron electrodes were used. Aluminum oxide flocs and iron oxide flocs were produced and can remove fluoride ion and arsenic ions effectively. Effects of ratio of the iron plate and aluminum plate, the current density, pH,coexisted cation-anions on the removal of fluoride and arsenic ions were investigated. The results showed that arsenic in the initial ion concentration of 1.0 mg/L, fluoride ion in the concentration of 5.0 mg/L can be simultaneously removed within 40 min with 120.0 mA and the ratio of iron to aluminum of 1:3. Meantime, both of the removal of As(III) and As(V) were efficient. Research was carried out in view of the complexing state of heavy metal pollutants of Cu-EDTA. Cu-EDTA was oxidized by electro-Fenton process, and Cu and EDTA ions were removed by flocculation, adsorption and coprecipitation of iron oxide etc together. Results shew that the removal rate of TOC value increased with the addition of current density and reaction. When the current density increased to 31.25 A/m2, TOC fell from 120.0 mg/L to 54.7 mg/L, removal rate of TOC was 54.4%. When the current density increased to 114.58 A/m2, he removal rate of TOC would reduce in the solution. Cu-EDTA was treated by electro-Fenton process, EDTA removal rate was much greater than the TOC in the solution. At 5.0 mins of electro-Fenton reaction, EDTA removal rate had reached to 99.0%. The increase of H2O2 dosage helped to improve the removal rate of TOC and EDTA. When the H2O2 dosage was 98.8 mmol/L, after 30 mins of electro-Fenton reaction, TOC removal rate was 74.2%. When the initial pH was 3.0, TOC removal efficiency was highest, oversize or undersize pH was detrimental to the TOC removal. At the early Fenton reaction, concentration of •OH was lower, while in the middle of electro-Fenton process, concentration of •OH was higher, the reason was mainly due to the effects of Fe2+ mass transfer rate. The treatment of the plugboard wastewater was performed by an optimal electrocoagulation and electro-Fenton. The organic components with suspended fractions accounting for 30.0% COD were preferably removed via electrocoagulation at initial 5.0 min.In contrast, the removal efficiency was increased to 76.0% with the addition of H2O2. The electrogenerated Fe2+ reacts with H2O2 and leads to the generation of OH, which is responsible for the higher COD removal.However, overdosage H2O2 will consume •OH generated in the electro-Fenton process and lead to the low COD removal.The COD removal efficiency decreased with the increased pH. The concentration of Fe2+ ions was dependent on the solution pH, H2O2 dosage and current density. The changes of organic characteristics in coagulation and oxidation process were differenced and evaluated using gel permeation chromatography,fluorescence excitation–emission scans and Fourier transform infrared spectroscopy. A laboratory-scale anode-Fenton (AF) followed by NaClO oxidation at a volume of 1.0 L was used to treat coal-into-oil wastewater. In the AF process, COD can be removed from 5500.0 mg/L to 2200.0 mg/L at the H2O2 dosage of 6.0% scale anode-Fenton (AF) followed to 550mg/L, and chromaticity raised a lot from 55.0 to 1790.0 because of Fe-organic complex produced by AF process. So NaClO was added into water to eliminate the complex in order to precipitate iron. Maximum removal AFeficiencies of 11.0%, 89.0%, 94.0% and 98.0% were obtained for COD, NH4-N, chromaticity and turbidity, respectively. |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/37043]  |
| 专题 | 生态环境研究中心_环境水质学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 张宝锋. 电化学处理水中无机物、重金属及金属有机络合物研究[D]. 北京. 中国科学院研究生院. 2016. |
入库方式： OAI收割
来源：生态环境研究中心
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