螯合剂和表面活性剂强化巨菌草修复铅镉复合污染土壤研究

发布时间：2018-08-12 16:18

【摘要】：采用外源添加螯合剂或表面活性剂强化植物修复重金属污染土壤,在国内外己受到广泛关注,并取得了突破性的成果。本文以因使用生活垃圾肥而引起的重金属污染土壤为研究对象,采用内梅罗综合指数评价了该地区重金属污染情况,选择出了目标重金属Pb和Cd；通过室内静态活化实验探索了不同类型的螯合剂和表面活性剂对重金属的活化效果,得出了最佳活化时间和浓度,并采用室内盆栽和田间实验研究了巨菌草在表面活性剂和螯合剂作用下对重金属污染土壤的修复效果：(1)以《温室蔬菜产地环境质量评价标准》为标准,通过内梅罗综合指数对土壤中Pb、Cd、As和Hg进行了评价,结果显示As内梅罗指数在标准范围内,Hg在轻度污染范围内,而Pb和Cd的内梅罗指数分别为2.69和9.17,Pb达到中度污染,Cd已达到重度污染水平,其含量分别为105.97 mg·kg~（-1）和1.84 mg·kg~（-1）。(2)添加EDTA.柠檬酸、TX~（-1）00和茶皂素强化作用后,土壤溶液中的pH值均有下降,EDTA和柠檬酸强化第7d时pH值降低最显著,较强化前降低了0.15～0.99个单位,而TX~（-1）00和茶皂素强化第14d时pH值降低最显著,较强化前降低了0.11～0.83个单位,随着强化时间的增加,土壤溶液的pH值逐渐增加并在第28d趋于稳定；除TX~（-1）00外,在其他强化剂作用下,土壤中Pb和Cd有效态含量在强化第7d时增加最为显著,在且随浓度越大有效态含量越高,随着强化时间的增加有效态含量在第28d逐渐趋于稳定。(3)强化作用第28d后的土壤形态分析表明：土壤中酸溶态和可还原态Pb和Cd占总百分含量变化较为显著,其中酸溶态在一定程度上有所增加,且随螯合剂和表面活性剂浓度的增加而增加,可还原态有所降低,在高浓度条件下,降低幅度较为显著。(4)采用盆栽实验,外源添加非离子表面活性剂TX~（-1）00和生物表面活性剂茶皂素强化巨菌草修复重金属污染土壤。发现在表面活性剂强化第28d时,土壤中Pb和Cd的酸溶态、可还原态和可氧化态含量及其总量均有不同程度降低,且茶皂素作用效果优于TX~（-1）00。(5)TX~（-1）00均提高了巨菌草体内Pb和Cd的累积量,浓度为5.0 mmol·L~（-1）时效果最显著,较对照组分别增加了73.52%和35.77%；在茶皂素作用下巨菌草体内Pb和Cd含量也有显著增加,当浓度为5.0g.L~（-1）时Pb最大增加了76.37%,当浓度为1.0g·L~（-1）时Cd最大增加了48.3%,比较TX~（-1）00和茶皂素强化效果发现茶皂素TX~（-1）00。(6)采用蔬菜基地田间实验,分别添加10.0 mmol·L~（-1）的EDTA和柠檬酸强化巨菌草修复污染土壤。酸溶态Pb和Cd变化最为显著,在根际土壤中的含量较非根际土壤显著增加,其中EDTA强化处理分别增加了26.78%和9.13%,柠檬强化处理分别增加了25.41%和2.23%。在EDTA和柠檬酸作用下,Pb和Cd在巨菌草体内的累积量显著增加,且EDTA效果显著于柠檬酸,较对照组分别增加了92.43%和26.79%。
[Abstract]:The application of exogenous chelating agent or surfactant in plant remediation of heavy metal contaminated soil has received extensive attention at home and abroad, and breakthrough results have been obtained. In this paper, the heavy metal polluted soil caused by the use of domestic waste fertilizer was used as the research object, the heavy metal pollution in this area was evaluated by the Nemero comprehensive index, and the target heavy metals Pb and CD were selected. The activation effects of different chelating agents and surfactants on heavy metals were investigated by static activation experiments in laboratory. The optimum activation time and concentration were obtained. Pot experiment and field experiment were used to study the remediation effect of macrobacillus on heavy metal contaminated soil under the action of surfactant and chelating agent. (1) the environmental quality evaluation standard of greenhouse vegetable producing area was taken as the standard. In this paper, the PbCd-Cd-As and Hg in soil were evaluated by Nemero index. The results showed that the index of as was in the range of light pollution within the standard range. The content of Pb and CD were 105.97 mg kg-1 and 1.84 mg kg-1). (2, respectively. The NMELO index of Pb and CD were 2.69 and 9.17%, respectively. The content of Pb and CD reached the level of severe pollution, and the contents were 105.97 mg kg-1 and 1.84 mg kg-1). (2, respectively. The pH value of soil solution decreased significantly after strengthening with citrate TX-1 00 and tea saponin. The pH value of EDTA and citric acid decreased most significantly at the 7th day, and the pH value of TX-1 00 and tea saponin decreased significantly at the 14th day, compared with that before strengthening. The pH value of soil solution increased gradually and became stable on the 28th day, except for TX-1 ~ (-1) 00, under the action of other strengthening agents, the pH value of soil solution decreased by 0.11 ~ (0.83) units, and the pH value of soil solution gradually increased with the increase of strengthening time. The contents of available forms of Pb and CD in soil increased most significantly at the 7th day of enrichment, and the higher the concentration of available forms was, the higher the content of available forms was with the concentration of Pb and CD. With the increase of strengthening time, the content of available state gradually stabilized on the 28th day. (3) the analysis of soil morphology after 28 days of intensification showed that the contents of acid soluble and reducible Pb and CD in the soil changed significantly. The acid soluble state increased to some extent and decreased with the increase of chelating agent and surfactant concentration. Exogenous Nonionic surfactant TX-1 00 and biosurfactant tea saponin were added to enhance the remediation of heavy metal contaminated soil. It was found that the acid soluble, reductive and oxidizable state contents and total amount of Pb and CD in soil were decreased in different degree when the surfactant was strengthened for 28 days, and the effect of tea saponin was better than that of TX-1 000.5TX-1 00 increased the accumulation of Pb and CD in macrobacillus grasses, and the effect of tea saponin was better than that of TX-1. (5) TX-1 00 increased the accumulation of Pb and CD in the soil. When the concentration was 5.0 mmol L ~ (-1), the effect was the most significant, which increased 73.52% and 35.77%, respectively, compared with the control group, and the contents of Pb and CD also increased significantly under the action of tea saponin. When the concentration was 5.0 g 路L ~ (-1), Pb increased 76.37g 路L ~ (-1), and CD increased 48.3% when the concentration was 1.0 g / L ~ (-1). Compared with TX-1 ~ (-1) 00 and tea saponin fortified effect, it was found that tea saponin TX-1 ~ (-1) 00. (6) the field experiment was carried out in vegetable field. EDTA and citric acid supplemented 10.0 mmol L ~ (-1) were used to strengthen the remediation of contaminated soil. The content of acid soluble Pb and CD in rhizosphere soil was significantly higher than that in non-rhizosphere soil. The contents of Pb and CD were increased by 26.78% and 9.13% in EDTA and 25.41% and 2.23% in lemon fortified soil, respectively. Under the action of EDTA and citric acid, the accumulative amount of Pb and CD in macrobacillus was significantly increased, and the effect of EDTA was significantly higher than that of citric acid, which was 92.43% and 26.79% higher than that of the control group, respectively.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X53

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