脉冲放电等离子体去除土壤中对硝基酚的研究

发布时间：2018-06-09 16:00

本文选题：脉冲放电等离子体 + 对硝基酚　；参考：《江苏大学》2017年硕士论文

【摘要】：基于传统修复方法修复有机污染土壤的局限,以及脉冲放电等离子体(pulsed discharge plasma,PDP)技术的诸多优点,本研究采用PDP技术处理污染土壤中的有机物。研究首先建立了对硝基酚(p-Nitrophenol,PNP)污染土壤的PDP处理体系,考察不同参数条件对于污染土壤中PNP降解的影响;其次,鉴于现实土壤污染的复杂性,研究模拟了PNP-Cu~(2+)复合污染土壤,并探究了各自浓度变化对于PNP降解率的影响,同时考察了添加粘土对于污染土壤的影响;最后,建立光谱检测体系,通过考察不同条件下体系中·OH和·O的相对含量及变化规律,说明·OH和·O在PDP修复有机污染土壤中的关键作用。研究结果归纳如下:(1)建立了七针-网式的脉冲放电等离子体土壤修复体系,以PNP为目标物,分别从电气参数、土壤特性及载气参数三方面考察了脉冲放电等离子体技术对PNP污染土壤修复的有效性,研究得出:脉冲峰值电压越高、PNP初始浓度越低、酸性环境及氧气环境都可以提高修复体系中PNP的降解效率。通过定量分析,得出以空气为载气的反应体系中PNP的两个主要降解中间产物为苯酚和邻苯二酚。(2)考察了PDP修复PNP体系中存在重金属离子Cu~(2+)对PNP降解情况的影响以及粘土矿物——高岭土的添加对PNP去除效果的影响规律。研究结果表明:当污染土壤中存在不同浓度的Cu~(2+)和一定浓度的PNP时,PNP降解率随着Cu~(2+)的加入而明显提高,且Cu~(2+)浓度越高,PNP降解率提高的越多;当向污染土壤中添加一定比例的高岭土并吸附一定时间后,不论是PNP污染土壤或是PNP-Cu~(2+)复合污染土壤,经PDP作用后,PNP的降解率都得到了明显提升。以上研究结果说明Cu~(2+)或高岭土的存在,均能提高PDP体系中PNP降解效果。(3)采用光谱检测技术测定载氧环境下PDP修复污染土壤体系中·OH和·O相对发射光谱强度的变化。通过对比实验分别考察了不添加土壤、添加原土、添加有机污染土壤和添加有机-重金属复合污染土壤的PDP体系中·OH和·O的相对发射光谱强度变化,同时考察了脉冲峰值电压、电极间距和O_2体积流量变化对·OH和·O的相对发射光谱强度的影响。研究结果表明:添加土壤有利于放电的发生而提高了PDP体系中·OH和·O的生成;添加有机污染土壤的PDP体系中·OH和·O发射光谱强度较原土体系中低,证明了PDP体系中·OH和·O于有机物的氧化作用;重金属离子的加入对于体系中有机物的自由基的生成有积极的促进作用。同时,脉冲峰值电压和O_2体积流量的增加有利于PDP体系中·OH和·O的产生,而电极间距的增加不利于PDP修复污染体系中·OH和·O的生成。该部分研究说明了·OH和·O在PDP用于污染土壤修复体系中的关键作用。
[Abstract]:Based on the limitation of the traditional remediation method and the advantages of pulsed discharge plasma-PDP (pulsed discharge plasma) technique, the organic matter in contaminated soil was treated by PDP. Firstly, the PDP treatment system of p-nitrophenol p-NitrophenolPNP) contaminated soil was established, and the effects of different parameters on PNP degradation in polluted soil were investigated. Secondly, in view of the complexity of actual soil pollution, the PNP-CuPNP2) contaminated soil was simulated. The effects of different concentrations on the degradation rate of PNP and the effect of adding clay on the contaminated soil were investigated. Finally, a spectrum detection system was established to investigate the relative content and variation of OH and O in the system under different conditions. The key role of OH and O in PDP remediation of organic contaminated soil was explained. The results are summarized as follows: (1) A seven-needle / netted pulsed discharge plasma soil remediation system is established. The PNP is taken as the target material, and the electrical parameters are taken into account. The effectiveness of pulsed discharge plasma technology in remediation of PNP contaminated soil was investigated from three aspects: the higher the peak voltage of pulse and the lower the initial concentration of PNP, the higher the peak voltage of the pulse was, the lower the initial concentration of PNP was. Acid environment and oxygen environment can improve the degradation efficiency of PNP in the remediation system. Through quantitative analysis, Two main degradation intermediates of PNP were phenol and catechol. 2) the effect of heavy metal ion CuPN 2) on PNP degradation and clay minerals were investigated. -the effect of kaolin addition on the removal of PNP. The results showed that the degradation rate of PNP in polluted soil increased with the addition of Cu2) and the degradation rate of PNP increased with the concentration of Cu (2). The higher the concentration was, the more the degradation rate of PNP was increased, and the higher the concentration was, the higher the degradation rate of PNP was. The higher the concentration was, the higher the degradation rate of PNP was. When a certain proportion of kaolin was added to the contaminated soil and adsorbed for a certain time, the degradation rate of PNP in PNP contaminated soil or PNP-CuP- (2) compound contaminated soil was obviously increased after PDP treatment. The above results show that the existence of Cujian2) or kaolin can improve the degradation effect of PNP in PDP system. The spectral detection technique is used to determine the changes of OH and O emission spectra in PDP remediation contaminated soil system under oxygen loading environment. The changes of the relative emission intensity of OH and O in PDP system without adding soil, adding original soil, adding organic contaminated soil and adding organic-heavy metal compound contaminated soil were investigated by contrast experiment. The peak pulse voltage was also investigated. The effects of electrode spacing and O _ 2 volume flow on the relative emission spectra of OH and O were investigated. The results showed that the formation of OH and O in PDP system was improved by adding soil, and the intensity of OH and O emission in PDP system was lower than that in original soil system. It is proved that the oxidation of OH and O in PDP system and the addition of heavy metal ions can promote the formation of free radicals in PDP system. At the same time, the increase of peak pulse voltage and volume flow of O _ 2 is beneficial to the production of OH and O in PDP system, but the increase of electrode spacing is not conducive to the formation of OH and O in PDP remediation system. In this part, the key role of OH and O in the remediation system of contaminated soil by PDP was explained.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

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