本文關(guān)鍵詞：等離子體—電化學(xué)耦合處理難降解廢水的應(yīng)用研究　出處：《蘇州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 耦合放電 難降解有機(jī)廢水 影響因素 放電傳質(zhì)反應(yīng)過(guò)程 降解機(jī)理

【摘要】：環(huán)境污染問(wèn)題日益得到廣泛關(guān)注。難降解有機(jī)污廢水的處理是目前環(huán)境工程界研究的焦點(diǎn)之一。氯酚是一種廣泛使用的化工原料,具有穩(wěn)定的化學(xué)性質(zhì)、結(jié)構(gòu)及較強(qiáng)的生物毒性,是一類優(yōu)先監(jiān)控的難降解有機(jī)污染物。因此,開展氯酚廢水處理的研究在工業(yè)應(yīng)用方面有著重要的理論與實(shí)際意義。本文提出一種新型的大氣壓放電等離子體-電化學(xué)耦合技術(shù),有效的實(shí)現(xiàn)了4-氯酚廢水及實(shí)際難降解有機(jī)廢水的氧化處理,并通過(guò)降解效果測(cè)定、氣泡影像采集、Danckwerts繪標(biāo)法及活性物種分析等多種技術(shù)途徑系統(tǒng)探討了主要影響因素對(duì)反應(yīng)體系的影響規(guī)律,并對(duì)相關(guān)機(jī)理進(jìn)行了研究。主要的研究?jī)?nèi)容和結(jié)論如下:(1)通過(guò)對(duì)耦合系統(tǒng)電源電壓的優(yōu)化,得到4-氯酚(4-CP)降解最優(yōu)耦合電壓為:電氧化電壓8.0 V,等離子體峰值電壓14.2 kV。經(jīng)對(duì)比發(fā)現(xiàn),在相同的放電時(shí)間內(nèi),耦合系統(tǒng)內(nèi)4-氯酚降解率遠(yuǎn)大于單獨(dú)電化學(xué)氧化和單獨(dú)等離子體放電系統(tǒng)。(2)通過(guò)研究耦合系統(tǒng)電解池溶液中鹽含量與4-氯酚降解率的變化關(guān)系,得到溶液的最佳鹽含量為80 mg/L NaCl。(3)溶液初始pH對(duì)4-氯酚降解率、溶液COD和TOC去除率的影響規(guī)律:初始pH為9.23時(shí),相同時(shí)間下,4-氯酚去除率達(dá)到88.28%(4-氯酚降解的平均能量效率為0.72 g/kWh),遠(yuǎn)高于pH為6.50和3.65時(shí)的81.32%和79.99%。COD去除率在堿性條件下最高,達(dá)到61.10%(COD去除的平均能量效率為1.35 g/kWh),而中性為59.44%,酸性為49.29%。TOC去除率堿性條件最高,酸性次之,中性最差。(4)利用靛蘭三磺酸鉀分光光度法、草酸鈦鉀比色法和對(duì)羥基苯甲酸捕獲法分別測(cè)定了耦合系統(tǒng)放電過(guò)程中產(chǎn)生的活性物質(zhì)O3、H2O2和?OH。在pH為3.65和9.23時(shí),O3的生成速率最快,且堿性大于酸性中的產(chǎn)率。酸性條件下,H2O2在90 min放電時(shí)間內(nèi)的產(chǎn)量最大,為0.0507 mmol/L,中性次之,堿性最少。堿性條件下,?OH生成速率達(dá)到了2.67×10-5 mmol/(L s),能量產(chǎn)率高達(dá)1.16×10-7 mol/J。由此說(shuō)明,在堿性條下促進(jìn)4-氯酚降解的主要活性物質(zhì)是O3和?OH,而在酸性和中性條件下為?OH和H2O2。(5)利用照相技術(shù)獲取了放電等離子體系統(tǒng)內(nèi)的瞬間氣泡影像,統(tǒng)計(jì)并計(jì)算了不同實(shí)驗(yàn)條件下的氣泡分布和特征參數(shù)。利用Danckwerts繪標(biāo)法,測(cè)定了相同體系中的氣-液傳質(zhì)系數(shù),發(fā)現(xiàn)理論計(jì)算與氣泡影像的統(tǒng)計(jì)結(jié)果基本一致,共同解釋了等離子體放電反應(yīng)器在不同條件下的傳質(zhì)反應(yīng)過(guò)程。(6)采用HPLC和IC對(duì)4-氯酚芳香類中間產(chǎn)物和小分子有機(jī)酸進(jìn)行測(cè)定。結(jié)合活性物質(zhì)和中間產(chǎn)物的分析可推斷4-氯酚在不同pH下的降解歷程:在酸性和中性溶液中,主要是由?OH和H2O2誘導(dǎo)的羥基鄰、對(duì)位上的親電取代反應(yīng),分別生成了4-氯鄰苯二酚和對(duì)苯二酚。在堿性溶液中,4-氯酚更易發(fā)生由臭氧化引發(fā)的親電取代反應(yīng),并伴隨著少量?OH引發(fā)的親電取代反應(yīng)。O3分子易攻擊羥基的鄰、對(duì)位碳原子,引起氯原子從4-氯酚苯環(huán)上脫去形成對(duì)苯二酚和苯酚,而羥基鄰位上的氫原子被?OH取代分別生成了4-氯鄰苯二酚。(7)利用耦合體系對(duì)實(shí)際難降解廢水進(jìn)行了應(yīng)用實(shí)驗(yàn)研究,結(jié)果發(fā)現(xiàn)在沒加催化劑的條件下,耦合系統(tǒng)處理難降解實(shí)際廢水的效果比加入催化劑更佳,COD的去除率較高,但隨著等離子體峰值電壓的增大,COD的去除率呈現(xiàn)下降的趨勢(shì)。在峰值電壓為14.2 kV時(shí),COD去除率高達(dá)67.68%。此時(shí),整體耗能又是最少的。同時(shí)經(jīng)過(guò)電氧化電壓和等離子體峰值電壓的交叉優(yōu)化,得到的最優(yōu)耦合電壓條件為:電氧化電壓5.0 V,等離子體峰值電壓16.6 kV。此時(shí),廢水COD的去除率為43.33%,能量效率為0.48 g/k Wh。
[Abstract]:The problem of environmental pollution has been widely concerned. To deal with the degradation of organic wastewater is one of the focus of research in the field of environmental engineering at present. Chlorophenol is a widely used chemical raw materials, has stable chemical properties, structure and strong biological toxicity, is a kind of priority organic pollutants monitoring. Therefore, to carry out research on chlorophenols wastewater treatment has important theoretical and practical significance in industrial application. This paper presents a novel atmospheric pressure plasma electrochemical coupling technology, the effective implementation of the 4- oxidation treatment of chlorophenol wastewater and actual refractory organic wastewater, and the degradation effect of determination of bubble image acquisition, effect of the main influence the factors on the reaction system of Danckwerts plotting method and active species analysis and other technical approach system, and the related mechanism was studied. The main research The contents and conclusions are as follows: (1) through the optimization of the coupling system of the power supply voltage, 4- chlorophenol (4-CP) degradation of optimal coupling voltage: electro oxidation voltage of 8 V, the plasma peak voltage of 14.2 kV. by comparison, at the same time of discharge, coupled system 4- chloro phenol degradation rate is far greater than the single electrochemical oxidation and a separate plasma discharge system. (2) through the study of the relationship between the coupling system of electrolysis pool solution and the salt content changes 4- chlorophenol degradation rate, the optimal solution of the salt content is 80 mg/L NaCl. (3) initial solution pH on 4- chlorophenol degradation rate, influence of solution COD and TOC removal rate: initial pH 9.23 at the same time, by 4-, the removal rate reached 88.28% (the average energy efficiency of 4- chlorophenol degradation is 0.72 g/kWh), far higher than the pH 6.50 and 3.65 was 81.32% and the highest rate of 79.99%.COD removal under alkaline conditions, COD removal reached 61.10% ( The average energy efficiency of 1.35 g/kWh), and neutral acid is 59.44%, the removal rate of 49.29%.TOC alkaline conditions the highest acidity of neutral, the worst. (4) using indigo three sulfonic acid potassium spectrophotometry, potassium titanyl oxalate colorimetry and p-hydroxybenzoic acid capture were measured by the method of discharge process coupling in the system of active material O3 and H2O2? OH. at pH 3.65 and 9.23, the rate of O3 formation is the fastest, and greater than the yield of alkaline acid. Under acidic conditions, H2O2 in the 90 min discharge time maximum yield was 0.0507 mmol/L, neutral second, the less alkaline alkaline conditions. Next, the formation rate reached 2.67? OH * 10-5 mmol/ (L s), the energy yield of 1.16 * 10-7 mol/J.. This indicates that in alkaline under promote the main active substances 4- chlorophenol degradation are O3 and OH?, and in acidic and neutral conditions for OH and H2O2.? (5) the use of photography the discharge plasma technology The moment the bubble image system, calculated bubble distribution and characteristic parameters under different experimental conditions. Using Danckwerts plotting method, the same system in the determination of gas - liquid mass transfer coefficient, theoretical calculation and statistics found that the bubble image results are basically the same, the common interpretation of mass transfer reaction process of plasma discharge reactor under the different conditions. (6) using HPLC and IC to 4- by aromatic intermediates and small molecular organic acids were determined. Combined with the analysis of degradation process of active substances and the intermediate products can be inferred 4- chlorophenol in different pH: in acidic and neutral solutions, is mainly composed of OH H2O2 and the adjacent hydroxyl? The induction of the para position of the electrophilic substitution reaction, were generated 4- chloride of catechol and hydroquinone. In alkaline solution, 4- chlorophenol occurred more often caused by ozonation of electrophilic substitution, and accompanied by a small amount of OH caused? The electrophilic substitution reaction of.O3 molecules to attack the hydroxyl o para carbon atoms caused by chlorine atoms from 4- chlorophenol benzene off formation of hydroquinone and phenol, and the hydrogen atoms on the ortho hydroxyl? 4- chloride catechol formation of OH substituted respectively. (7) the actual wastewater was applied to experimental study using coupling the results found in the system, without catalyst under the condition of coupling system in treatment of refractory wastewater is better than adding catalyst is better, the removal rate of COD is higher, but with the increase of plasma peak voltage, the removal rate of COD decreased. The peak voltage is 14.2 kV, the removal rate of COD is up to 67.68%. at this time again, the overall energy consumption is minimal. At the same time through the cross optimization electro oxidation voltage and peak voltage of plasma, the optimal coupling voltage conditions are obtained: electro oxidation voltage of 5 V, the plasma peak voltage of 16.6 At this time, the removal rate of COD in the wastewater is 43.33% and the energy efficiency is 0.48 g/k Wh.

【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X703

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