水体中菲的光降解途径与影响因素研究

发布时间：2017-12-27 04:22

本文关键词：水体中菲的光降解途径与影响因素研究　出处：《辽宁大学》2016年硕士论文　论文类型：学位论文

更多相关文章： PHE 光降解 降解途径 影响因素

【摘要】：多环芳烃(Polycyclic Aromatic Hydrocarbon, PAHs)是一类在环境中可持久性存在的有机污染物。大部分多环芳烃具有致癌、致畸、致突变作用,可通过不同介质的生态循环蓄积在环境和生物体内,对环境和生物体存在着巨大的潜在或直接危害。菲(Phenanthrene)是多环芳烃中比较典型的具有致癌性的K区和惰性“湾”区的三环芳烃,其分子量小、结构较简单,已成为众多环境科研工作者研究多环芳烃的最具代表性物质。目前对于菲在环境中的处理办法主要有物理法、化学法、生物法等。用物理法处理菲仅仅在不同介质中的转移,并未从根本上使之降解乃至消除；用生物法处理环境中的菲,虽然运行资金少、处理效率高、无二次环境污染,但生物法处理时耗费时间长且有地域性差异、适用范围有较大限制；用化学法特别是高级氧化技术处理菲,降解效果好、处理时间短、无太大环境要求,但处理成本较高。鉴于此,本论文提出通过利用光源并添加一些辅助物质光化学降解菲,以期降低处理成本和达到较好的处理效果。研究了菲的光化学降解处理方法。首先,针对菲在环境中光化学降解途径进行了研究,通过含氧环境(好氧-厌氧)的不同考察了菲光降解状态是直接光降解或间接光降解。其次,通过查阅文献选择PHE初始浓度、pH、HA浓度、Cl-浓度、NO3-浓度、H2O2浓度六个影响因素考察对菲的光降解过程影响。最后,在单因素实验基础上筛选影响因素进一步考察各因素之间交互作用对菲光降解的影响。得出以下结论：针对不同光源和不同含氧条件进行了菲光降解实验,好氧条件下紫外光源照射180 min菲将降解效率最好,作为后续实验基础条件。菲光降解途径实验中发现,好氧条件下,菲的光降解过程以光氧化过程为主,直接光降解和光敏化降解为辅助；厌氧条件下,菲的光降解过程通过直接光降解。整个光降解过程有活性氧物种1O2、·OH参与。菲的单因素实验中,在实验范围内,随PHE的初始浓度的增加菲光降解效率不断降低,从而起到抑制作用；pH值对菲的光降解过程影响效果不大,菲光降解效率较平缓波动；Cl-浓度和NO：,-浓度随着浓度不断增加对菲的光降解反应过程起到了促进作用；HA在实验范围内随着自身浓度的不断增加,菲光降解效率也不断降低,HA起到抑制作用；H2O2随着浓度的不断增加,菲的光降解效率先增大后减小。中心组合实验设计四因子五水平实验,考察了不同因素(PHE初始浓度、HA浓度、H2O2浓度、C1-浓度)之间交互作用对菲光降解过程的影响。实验结果表明：四个影响因素均是菲光降解过程的显著性影响因素,影响顺序为HA浓度PHE初始浓度H2O2浓度Cl-浓度；经过多因素实验优化得出,在PHE初始浓度2.8μM、HA Omg/L、H2O2浓度0.05mM、C1浓度0.5M时,菲的光降解效率可达52.75%。
[Abstract]:Polycyclic Aromatic Hydrocarbon (PAHs) is a class of organic pollutants that can persist in the environment. Most PAHs have carcinogenic, teratogenic and mutagenic effects. They can accumulate in the environment and organisms through different ecological cycles, which have great potential or direct harm to environment and organisms. Phenanthrene (Phenanthrene) is a typical carcinogenic K region and inert Bay area of PAHs. Its molecular weight is small and its structure is relatively simple. It has become the most representative material for many environmental researchers to study polycyclic aromatic hydrocarbons. At present, there are mainly physical, chemical and biological methods for the treatment of phenanthrene in the environment. By physical Fa Lee Faye only in different medium, the degradation did not fundamentally make use of biological treatment and eliminate; environment in Philippines, while running less capital, high treatment efficiency, no two pollution, but when the biological process takes a long time and there are regional differences, larger applicable range limit by using chemical method; especially the advanced oxidation technology of phenanthrene, degradation effect, short treatment time, no big environmental requirements, but the high cost of processing. In view of this, this paper proposed that the photochemical degradation of phenanthrene by using light source and adding some auxiliary materials to reduce the cost of treatment and to achieve better treatment effect. The photochemical degradation treatment of phenanthrene was studied. First, the photochemical degradation pathways of phenanthrene in the environment were studied. The degradation of phenanthrene was directly photodegradation or indirect photodegradation through the different oxygen environment (aerobic anaerobic). Secondly, six factors, including initial concentration of PHE, pH concentration, HA concentration, Cl- concentration, NO3- concentration and H2O2 concentration, were selected to investigate the photodegradation process of phenanthrene. Finally, the influence factors of interaction on phenanthrene photodegradation were further investigated on the basis of single factor experiments. The following conclusions are drawn: for different light sources and different oxygen conditions, phenanthrene photodegradation experiment is carried out. Under ultraviolet irradiation, 180 min phenanthrene will give the best degradation efficiency under aerobic condition, which will serve as a basic condition for subsequent experiments. In the experiment of phenanthrene photodegradation, it is found that photodegradation is the main process of photodegradation of phenanthrene under aerobic conditions, and photodegradation and photosensitization degradation are the main auxiliary. Under anaerobic conditions, the photodegradation process of phenanthrene is directly photodegraded. The whole photodegradation process is involved in the active oxygen species 1O2,. OH. Single factor experiment of phenanthrene, in the experimental range, with the increase of initial PHE concentration of phenanthrene degradation efficiency decreases, thus inhibiting effect; pH value of phenanthrene degradation process has little effects, the Philippines photodegradation efficiency with gentle fluctuation; the concentration of Cl- and NO:, with the concentration increasing light concentration degradation of phenanthrene promoted; HA in the experimental range, with the increase of its concentration, the Philippines photodegradation efficiency also decreases, HA plays an inhibitory effect; with the increase of H2O2 concentration, the photodegradation efficiency of phenanthrene increased first and then decreased. The central composite experiment was designed with four factor and five level experiment. The interaction between different factors (PHE initial concentration, HA concentration, H2O2 concentration and C1- concentration) on the degradation process of phenanthrene was investigated. The experimental results show that the four factors are significant factors that influence the photocatalytic degradation process of phenanthrene, influence the order of HA concentration of initial PHE concentration H2O2 Cl- concentration; after the optimum factors, in the initial concentration of PHE 2.8 M, HA Omg/L, H2O2 0.05mM, C1 concentration 0.5M concentration, the photocatalytic degradation of phenanthrene the efficiency can reach 52.75%.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X52

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