PAHs污染土壤的环糊精及植物强化微生物修复效应

发布时间：2018-02-14 10:26

  本文关键词： 土壤粒径 PAHs 微生物修复 甲基β环糊精 紫花苜蓿　出处：《贵州大学》2015年硕士论文　论文类型：学位论文

【摘要】：多环芳烃(Polycylic aromatic hydrocarbons,PAHs)是一类疏水性有机污染物,且化学性质较稳定,在土壤中不易降解,会造成土壤PAHs的严重污染。PAHs长期滞留于土壤中,对土壤微生物、植物以及动物会造成不可逆的损伤,使土壤环境存在潜在生态风险。众所周知,PAHs一旦进入土壤环境,常与土壤有机质紧密结合,在物理、化学及生物过程等共同作用下发生老化现象,导致PAHs在土壤中的生物可利用性降低,影响PAHs从土壤中的去除效率。因此,为了进一步提高土壤中PAHs的修复效率,本文以环糊精及植物作为强化手段,较为系统地研究甲基β环糊精对不同粒径土壤中PAHs的微生物修复强化作用及土壤中PAHs的三相解析动力学特征,以及紫花苜蓿对土壤不同粒径组分中PAHs的微生物修复强化作用,为研发PAHs污染土壤的微生物修复技术提供科学依据。取得的主要结果如下:(1)通过室内微域培养试验结果发现,高效降解菌HPD-2处理组PAHs去除率最高,培养2周及4周后,在不同粒径中5环PAHs的去除率均高于2、3、4环中的去除率,且低环PAHs在较小粒径中去除率较高。接种降解菌HPD-2后土壤过氧化氢酶、多酚氧化酶、脲酶活性得到明显提高。荧光定量PCR分析结果表明,培养1周后HPD处理组和环糊精(MCD)强化处理组的优势降解菌HPD-2丰度增大,培养4周时HPD处理及H+M处理HPD-2丰度显著上升。当培养至5周时,土壤中HPD-2的数量减少,恢复至培养1周时的降解菌数量。这与土壤中PAHs含量的动态变化具有一致性。(2)运用Tenax TA树脂提取修复前后土壤中PAHs,并模拟了其三阶段解吸动力学过程。动力学过程模拟结果显示,添加MCD的处理,慢速解析与极慢速解析组分的比例较其他处理增大,Fsl及Fvl分别为1.942与2.363。而且修复4周过程中,Fsl及Fvl值逐渐增大,这说明MCD对土壤中PAHs的增溶作用越来越强。(3)盆栽试验结果表明,紫花苜蓿-根瘤菌联合作用对土壤中PAHs具有明显的去除效果,其去除率达60%以上。不同粒径组分中PAHs含量分布表现为细砂粉砂粉粒黏粒,且PAHs含量达显著性差异。低环(2、3环)PAHs在各粒径组分中去除率较低(20%以下),四环PAHs的去除主要存在于粉砂及细砂中,5环PAHs的去除则主要存在于黏粒与粉粒中。研究还发现,低环PAHs在培养过程中可以在不同粒径组分间发生非均衡分配,以2环PAHs分配为主转为3环PAHs的分配,不同处理后3环PAHs所占比例明显升高。
[Abstract]:Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic pollutants, which have stable chemical properties and are not easily degraded in soil, which will cause serious pollution of PAHs in soil. Plants and animals can cause irreversible damage, resulting in potential ecological risks to the soil environment. It is well known that once PAHs enter the soil environment, they are often closely combined with soil organic matter in physics, In order to further improve the remediation efficiency of PAHs in soil, the bioavailability of PAHs in soil is decreased, and the removal efficiency of PAHs is affected by the combined action of chemical and biological processes. In this paper, using cyclodextrin and plants as means of enhancement, the microbial remediation of PAHs in soils with different particle sizes and the kinetic characteristics of PAHs in soil were studied systematically by methyl 尾 -cyclodextrin (尾 -cyclodextrin). And the microbial remediation of alfalfa on different particle size components of soil provides scientific basis for the development of microbial remediation technology for PAHs contaminated soil. The main results obtained are as follows: 1) the results of laboratory microculture experiments show that, The removal rate of PAHs was the highest in the HPD-2 treatment group. After 2 and 4 weeks of culture, the removal rate of 5-ring PAHs in different particle size was higher than that in 2 ~ 3N ~ 4 ring. The activities of catalase, polyphenol oxidase and urease in soil were obviously increased after inoculation with HPD-2. The results of fluorescence quantitative PCR analysis showed that the activity of catalase, polyphenol oxidase and urease were significantly increased after inoculation with HPD-2. After 1 week of culture, the HPD-2 abundance of dominant degrading bacteria increased in HPD treatment group and cyclodextrin MCD-enhanced treatment group, and the HPD-2 abundance of HPD treatment and H M treatment increased significantly after 4 weeks of culture. When cultured to 5 weeks, the amount of HPD-2 in soil decreased. It is consistent with the dynamic change of PAHs content in soil. (2) Tenax TA resin is used to extract PAHs from the soil before and after remediation, and its three stage desorption kinetic process is simulated. The simulation results show that, When MCD was added, the ratio of slow to very slow resolution components was 1.942 and 2.363, respectively, and the FSL and Fvl values of FSL and Fvl increased gradually during the 4 weeks of repair. The results of pot experiment showed that the combined effect of alfalfa and rhizobia had obvious effect on PAHs removal in soil. The removal rate is over 60%. The distribution of PAHs content in different particle size components is fine sand silt clay. The content of PAHs was significantly different. The removal rate of PAHs was lower than 20% in each particle size fraction, while the removal of PAHs from silt and fine sand was mainly found in clay and silt. During the culture of low ring PAHs, the disequilibrium distribution occurred among different particle size components, and the distribution of 2-ring PAHs was changed into that of 3-ring PAHs, and the proportion of 3-ring PAHs increased obviously after different treatments.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X17

【参考文献】

相关期刊论文 前10条

1 谢凝子;;环糊精在土壤有机污染物治理中的应用[J];环境科学与管理;2009年02期

2 廖文菊;;环糊精在有机污染土壤生物修复中的应用[J];环境保护科学;2010年06期

3 钟茂生;姜林;夏天翔;姚珏君;丁爱中;陈刚;;基于土壤中多环芳烃解吸特性的生物修复效果评价[J];环境科学学报;2012年03期

4 倪进治;骆永明;魏然;李秀华;钱薇;;长江三角洲地区土壤环境质量与修复研究 Ⅴ.典型地区农业土壤中多环芳烃的污染状况及其源解析[J];土壤学报;2008年02期

5 俞飞,林玉锁;城市典型工业生产区及附近居住区土壤中PAHs污染特征[J];生态环境;2005年01期

6 许超;夏北成;;土壤多环芳烃污染根际修复研究进展[J];生态环境;2007年01期

7 余莉莉;李军;刘国卿;刘向;祁士华;张干;;珠江三角洲表层土壤中的多环芳烃[J];生态环境;2007年06期

8 毛健;骆永明;滕应;李振高;;一株副球菌对污染土壤中多环芳烃的降解研究[J];土壤;2009年03期

9 彭驰;王美娥;廖晓兰;;城市土壤中多环芳烃分布和风险评价研究进展[J];应用生态学报;2010年02期

10 尹春芹;蒋新;杨兴伦;卞永荣;王芳;;施肥对花红苋菜吸收和积累土壤中PAHs的影响[J];中国环境科学;2008年08期

相关硕士学位论文 前1条

1 王菲;多环芳烃污染土壤的微生物修复对微生物种群的影响[D];中国海洋大学;2010年

，

本文编号：1510492