隔膜气—液放电等离子体降解水中有机污染物的研究

发布时间：2018-04-03 20:01

  本文选题：隔膜气-液放电　切入点：降解　出处：《大连海事大学》2017年硕士论文

【摘要】：低温等离子体水处理技术是集物理、化学、光学等于一体的新型高级氧化水处理技术,可形成紫外光福射、高能电子轰击、高氧化活性粒子等多因素协同作用,具有反应速率快、氧化能力强、不产生二次污染等优点。其中,气液两相放电等离子体技术相比较液相放电更加容易、稳定,与纯气相放电相比较其传质速度快更加迅速,在处理水中难降解有机污染物方面具有明显的优势。本研究采用自制的隔膜气-液放电反应器,研究其在不同放电载气的隔膜放电特性,并应用该反应器在不同实验条件下以偶氮染料艳红B和苯酚为研究对象进行放电等离子体氧化降解研究,实验结论如下:(1)在隔膜气-液放电过程中可产生.OH和O.强氧化性自由基,并且在氧气为放电载气时其相对光谱强度最强;而在以空气和氩气为放电载气时,其发射峰分别以N_2谱带和Ar Ⅰ谱带为主;随着放电时间的延长,不同载气放电下液相中溶解的O_3和H_2O_2浓度都逐渐升高;当氧气为放电载气时,形成的O_3和H_2O_2浓度最高,在放电10 min后其浓度值分别达到11.42 mg/L和85.38 mg/L。(2)在输入能量一定时,艳红B的降解率随着隔膜气-液放电孔数的增加而升高;在酸性强,电导率小的实验条件下有利于艳红B和苯酚的降解;在隔膜气-液放电体系中氧气为放电载气时的去除效果最好,其次为氩气和空气;并且当氧气为放电载气时,去除苯酚的能量效率最高,可达到2.250 g/kWh。(3)羟基自由基清除剂的添加对艳红B和苯酚的降解均具有抑制作用,表明·OH是放电反应过程中降解有机污染物的重要活性粒子;Fe~(2+)的添加对艳红B和苯酚的降解均具有催化作用,在本放电体系中Fe~(2+)的最佳投放浓度为0.4 mmol/L。(4)艳红 B 的降解产物中有 Cl-、NO_3~-、NO_2~-、SO_4~(2-)、CH_3COOH、HCOOH、HOOCCOOH,表明艳红B染料的偶氮键断裂以及苯环和萘环结构发生了开环并断链的一系列氧化过程;苯酚的降解中间产物主要有四种:间苯二酚、对苯二酚、邻苯二酚和对苯醌,其中间产物的浓度有先升高后降低的一个变化趋势,并随着放电时间的延长逐渐消失,最终的产物为二氧化碳和水。
[Abstract]:The low temperature plasma water treatment technology is a new advanced oxidation water treatment technology which integrates physics, chemistry and optics. It can form the cooperation of ultraviolet radiation, high energy electron bombardment, highly oxidized active particles and so on.It has the advantages of fast reaction rate, strong oxidation ability and no secondary pollution.The gas-liquid two-phase discharge plasma technology is easier and more stable than liquid-phase discharge, and its mass transfer rate is faster and faster than that of pure gas-phase discharge, and it has obvious advantages in the treatment of refractory organic pollutants in water.In this study, a self-made membrane gas-liquid discharge reactor was used to study the characteristics of membrane discharge in different discharge carrier gases.The oxidation degradation of azo dye brilliant red B and phenol by discharge plasma was studied in this reactor under different experimental conditions. The experimental results are as follows: 1) during the membrane gas-liquid discharge, .OH and O can be produced.The relative spectral intensity of strongly oxidized free radicals is the strongest when oxygen is the discharge carrier gas, while the emission peaks are mainly N2 and ar I bands when air and argon are the discharge carrier gas, respectively, with the prolongation of discharge time,The degradation rate of brilliant red B increased with the increase of gas-liquid discharge pore number, and was favorable to the degradation of brilliant red B and phenol under the conditions of strong acidity and low conductivity.In the membrane gas-liquid discharge system, the removal efficiency of phenol is the highest when oxygen is the discharge carrier gas, followed by argon and air, and when oxygen is the discharge carrier gas, the removal efficiency of phenol is the highest.The addition of hydroxyl radical scavenger can inhibit the degradation of red B and phenol.The results showed that the addition of OH, an important active particle for degradation of organic pollutants during discharge reaction, could catalyze the degradation of both brilliant red B and phenol.鍦ㄦ湰鏀剧數浣撶郴涓璅e~(2 )鐨勬渶浣虫姇鏀炬祿搴︿负0.4 mmol/L.(4)鑹崇孩 B 鐨勯檷瑙ｄ骇鐗╀腑鏈，

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