本文關(guān)鍵詞： 土壤粒徑 PAHs 微生物修復 甲基β環(huán)糊精 紫花苜蓿　出處：《貴州大學》2015年碩士論文　論文類型：學位論文

【摘要】：多環(huán)芳烴(Polycylic aromatic hydrocarbons,PAHs)是一類疏水性有機污染物,且化學性質(zhì)較穩(wěn)定,在土壤中不易降解,會造成土壤PAHs的嚴重污染。PAHs長期滯留于土壤中,對土壤微生物、植物以及動物會造成不可逆的損傷,使土壤環(huán)境存在潛在生態(tài)風險。眾所周知,PAHs一旦進入土壤環(huán)境,常與土壤有機質(zhì)緊密結(jié)合,在物理、化學及生物過程等共同作用下發(fā)生老化現(xiàn)象,導致PAHs在土壤中的生物可利用性降低,影響PAHs從土壤中的去除效率。因此,為了進一步提高土壤中PAHs的修復效率,本文以環(huán)糊精及植物作為強化手段,較為系統(tǒng)地研究甲基β環(huán)糊精對不同粒徑土壤中PAHs的微生物修復強化作用及土壤中PAHs的三相解析動力學特征,以及紫花苜蓿對土壤不同粒徑組分中PAHs的微生物修復強化作用,為研發(fā)PAHs污染土壤的微生物修復技術(shù)提供科學依據(jù)。取得的主要結(jié)果如下:(1)通過室內(nèi)微域培養(yǎng)試驗結(jié)果發(fā)現(xiàn),高效降解菌HPD-2處理組PAHs去除率最高,培養(yǎng)2周及4周后,在不同粒徑中5環(huán)PAHs的去除率均高于2、3、4環(huán)中的去除率,且低環(huán)PAHs在較小粒徑中去除率較高。接種降解菌HPD-2后土壤過氧化氫酶、多酚氧化酶、脲酶活性得到明顯提高。熒光定量PCR分析結(jié)果表明,培養(yǎng)1周后HPD處理組和環(huán)糊精(MCD)強化處理組的優(yōu)勢降解菌HPD-2豐度增大,培養(yǎng)4周時HPD處理及H+M處理HPD-2豐度顯著上升。當培養(yǎng)至5周時,土壤中HPD-2的數(shù)量減少,恢復至培養(yǎng)1周時的降解菌數(shù)量。這與土壤中PAHs含量的動態(tài)變化具有一致性。(2)運用Tenax TA樹脂提取修復前后土壤中PAHs,并模擬了其三階段解吸動力學過程。動力學過程模擬結(jié)果顯示,添加MCD的處理,慢速解析與極慢速解析組分的比例較其他處理增大,Fsl及Fvl分別為1.942與2.363。而且修復4周過程中,Fsl及Fvl值逐漸增大,這說明MCD對土壤中PAHs的增溶作用越來越強。(3)盆栽試驗結(jié)果表明,紫花苜蓿-根瘤菌聯(lián)合作用對土壤中PAHs具有明顯的去除效果,其去除率達60%以上。不同粒徑組分中PAHs含量分布表現(xiàn)為細砂粉砂粉粒黏粒,且PAHs含量達顯著性差異。低環(huán)(2、3環(huán))PAHs在各粒徑組分中去除率較低(20%以下),四環(huán)PAHs的去除主要存在于粉砂及細砂中,5環(huán)PAHs的去除則主要存在于黏粒與粉粒中。研究還發(fā)現(xiàn),低環(huán)PAHs在培養(yǎng)過程中可以在不同粒徑組分間發(fā)生非均衡分配,以2環(huán)PAHs分配為主轉(zhuǎn)為3環(huán)PAHs的分配,不同處理后3環(huán)PAHs所占比例明顯升高。
[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.
【學位授予單位】：貴州大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X53;X17

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