三峡库区消落带土壤重金属污染的微生物修复技术研究

发布时间：2019-03-20 20:45

【摘要】：随着现代工业的发展,重金属土壤污染已成为日渐突出的环境问题,时刻威胁着动植物的生长、人类的身体健康和生态环境的破坏。国内外许多关于土壤重金属污染的修复研究不胜枚举,但成果不太明显,传统的土壤重金属污染修复方法因各种限制已不能满足实际需求,近年来,土壤重金属微生物修复以其高效率、无二次污染等特点,已成为国内外一个新型的研究领域,引起了人们的广泛关注。本课题前期已针对消落带重金属污染土壤进行了相关植物修复技术研究,并取得一定研究进展,修复效果理想。本研究在前期基础之上,选取具有较佳植物修复效果的三峡库区消落带云阳段土样为研究对象,从土样中筛选分离出5种对铜、锌、镉具有去除作用的菌株。其中,B01为具有去除Cu2+作用的菌株,B02、B03为具有去除Cd2+作用的菌株,B04、B05为具有去除Zn2+作用的菌株。上述菌株经过培养、富集与分离纯化,初步鉴定结果为:B01、B02、B04为产碱菌属;B03为黄假胞菌属;B05为假单胞菌属。实验中,根据不同pH、温度、重金属离子初始浓度,设置单一因子变化分别配置不同的营养液对Cu2+、Cd2+、Zn2+的去除作用进行观察,其中,菌株B01去除Cu2+,菌株B02、B03去除Cd2+,菌株B04、B05去除Zn2+。实验结果表明:菌种B01去除Cu2+的实验,重金属去除率分别与p H、温度的变化曲线为先上升后下降,与Cu2+初始浓度的变化呈负相关;Cu2+去除量与Cu2+初始浓度的变化曲线为先上升后下降;pH在7时,Cu2+的去除率达到最高值,为70%;温度为30℃时,Cu2+的去除率达到最高值,为70%;Cu2+初始浓度为100mg/L时,Cu2+的去除量达到最高值,为70mg/L。菌种B01对铜的去除作用在30~100mg/L Cu2+浓度时满足零级动力学方程。菌株B02、B03去除Cd2+的实验,重金属去除率分别与pH、温度的变化曲线为先上升后下降,与Cd2+初始浓度的变化呈负相关;Cd2+去除量与Cd2+初始浓度的变化曲线为先上升后下降;pH在7时,菌株B02、B03对Cd2+的去除率达到最高值,分别为66%、42%;温度为30℃时,菌株B02、B03对Cd2+的去除率达到最高值,分别为66%、42%;Cd2+初始浓度为70mg/L时,菌株B02、B03对Cd2+的去除量达到最高值,分别为49mg/L、40.6mg/L。菌种B02、B03对镉的去除作用在30~70mg/L Cd2+浓度时满足零级动力学方程。菌株B04、B05去除Zn2+的实验,重金属去除率分别与pH、温度的变化曲线为先上升后下降,与Zn2+初始浓度的变化呈负相关;Zn2+去除量与Zn2+初始浓度的变化曲线为先上升后下降;pH在7时,菌株B04、B05对Zn2+的去除率达到最高值,分别为68%、65%;温度为30℃时,菌株B04、B05对Zn2+的去除率达到最高值,分别为63%、58%;Zn2+初始浓度为150mg/L时,菌株B04、B05对Zn2+的去除量达到最高值,分别为67.5mg/L、61.5mg/L。菌种B04、B05对镉的去除作用分别在10~200mg/L和10~150mg/L Zn2+浓度时满足零级动力学方程。
[Abstract]:With the development of modern industry, heavy metal soil pollution has become an increasingly prominent environmental problem, threatening the growth of animals and plants, human health and the destruction of ecological environment. There are many researches on remediation of soil heavy metal pollution at home and abroad, but the results are not obvious. The traditional remediation methods of soil heavy metal pollution can not meet the actual needs because of various restrictions, in recent years, Microbial remediation of heavy metals in soil has become a new research field at home and abroad because of its high efficiency and no secondary pollution. Some researches on phytoremediation of soils contaminated by heavy metals have been carried out in the early stage of this project, and some progress has been made in the research, and the effect of remediation is satisfactory. On the basis of the previous study, the soil samples of Yunyang section of the fluctuation zone in the three Gorges Reservoir area, which have better phytoremediation effect, were selected as the object of study. Five strains with removal effects on copper, zinc and cadmium were screened and isolated from the soil samples. Among them, B01 is the strain with Cu2 removal, B02, B03 is the strain with removal of Cd2, B04, B05 is the strain with the effect of removing Zn2. After culture, enrichment and purification, the results were as follows: B01, B02, B04, Pseudomonas flavum, B05, Pseudomonas, B03, B05, B01, B02, B04, B03, and B05, respectively. In the experiment, according to the different pH, temperature, the initial concentration of heavy metal ions and the change of single factor, the effects of different nutrient solution on the removal of Cu2, Cd2 and Zn2 were observed. Among them, strain B01 removed Cu2, strain B02, strain B03 removed Cd2, while strain B01 removed Cu2, strain B02, and strain B03 removed Cd2. Strain B04, B05 removed Zn2. The experimental results showed that the removal rate of heavy metals was first increased and then decreased with pH and temperature of strain B01, which was negatively correlated with the change of initial concentration of Cu2. The results showed that the removal rate of heavy metals was negatively correlated with the initial concentration of Cu2. The curve of removal of Cu2 and initial concentration of Cu2 increased first and then decreased, the removal rate of Cu2 reached the highest value of 70% when pH was at 7, and the removal rate of Cu2 reached to the highest value of 70% at 30 鈩，

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