大豆秸秆生物炭对金属硫化物尾矿污染土壤的修复作用

发布时间：2018-05-02 00:10

本文选题：重金属 + 金属硫化物尾矿　；参考：《湖南科技大学》2017年硕士论文

【摘要】：金属硫化物矿山尾矿污染不同于一般成因的重金属污染,还存在尾矿中硫化矿物氧化产酸并不断释放重金属的问题。由于氧化作用,硫化物尾矿产生大量含重金属和硫酸根离子的酸性矿山废水,对周边生态环境造成严重影响,并通过食物链作用对人体健康构成威胁。生物炭因具有独特物理化学性质,可以通过静电吸附、离子交换、表面络合及共沉淀等方式有效降低土壤重金属的活性和毒性,起到修复土壤的作用。为控制硫化物尾矿氧化带来的环境影响,本论文以江西银山矿业选矿厂尾矿为研究对象,采用生物炭处理尾矿的方式,抑制尾矿氧化,控制重金属和硫酸根离子的释放。并通过模拟金属矿山尾矿污染土壤为研究对象,采用盆栽试验和发芽试验,研究了生物炭施用于尾矿污染土壤,对植物生长及吸收土壤重金属的影响,探讨生物炭在金属硫化物矿山尾矿重金属污染土壤中的修复潜力。主要结论如下:(1)在500℃制备的大豆秸秆生物炭,pH值大于7,表现出碱性。傅立叶红外光谱分析可知生物炭含有羟基、芳香结构以及酸性含氧官能团等,扫描电镜观察其表面形貌可知生物炭具有多孔结构,微孔数量多且形状规则,比表面积大。(2)通过对铜尾矿的理化性质进行分析,尾矿主要成分有石英、针铁矿、赤铁矿与少量石膏、高岭石等,主要元素有Fe、Al、Si以及少量的S等。通过对铜尾矿重金属总量测定分析,铜尾矿中总金属Cu、Zn和Pb含量都很高,Cd含量相对较低。(3)在淹水条件下的氧化实验,结果表明,双氧水作为氧化剂能够加速尾矿氧化,使尾矿迅速氧化生成大量的Fe~(3+)和SO_4~(2-),且使溶液中重金属含量明显增大。在双氧水加速氧化环境下,生物炭仍然能发挥良好的钝化效果。在自然氧化过程中,生物炭能够明显提高尾矿pH,抑制尾矿氧化,固化重金属。(4)在干湿交替条件下的氧化实验,结果表明,在尾矿污染土壤中,生物炭能提高土壤pH,降低土壤体系氧化性,抑制尾矿氧化产酸作用,降低重金属含量。而生物炭与油酸钠/硅酸钠协同处理在提高土壤pH值、降低氧化性、抑制硫酸根产生及钝化重金属效果上都比生物炭单独处理效果好。其中,硅酸钠与生物炭协同处理土壤pH值最大,油酸钠在降低硫酸根含量上效果最明显。在铜尾矿污染土壤组中,对于提高土壤pH、降低氧化性,抑制重金属释放效果生物炭不如油酸钠和硅酸钠。而在锌尾矿污染土壤组中,生物炭对重金属释放的抑制效果比油酸钠和硅酸钠好。(5)盆栽实验和发芽实验结果表明,添加生物炭能明显促进空心菜生长,其中生物炭对空心菜根部生长的影响比茎叶效果更为明显。空心菜组织中的Cu、Zn、Pb、Cd含量与土壤中Cu、Zn、Pb、Cd浓度呈现出显著的正相关性。生物炭明显降低空心菜中Cu、Zn、Pb、Cd的含量,钝化土壤重金属作用明显。生物炭能显著提高污染土壤pH值,明显缓解硫化矿物氧化产酸问题。在复合重金属污染土壤中,生物炭在减少空心菜植株含重金属Pb的效果最为显著。生物炭能减轻尾矿污染土壤对空心菜种子的毒害作用,提高种子的发芽率和成苗率。
[Abstract]:The pollution of metal sulfide mine tailings is different from the common cause of heavy metal pollution. There are also the problems of oxidation of sulphide minerals in the tailings and the continuous release of heavy metals in the tailings. The sulphide tailings produce a large number of acid mine wastewater containing heavy metals and sulfate ions, which have serious effects on the surrounding ecological environment and through food. Because of its unique physical and chemical properties, biological charcoal can effectively reduce the activity and toxicity of heavy metals in soil by electrostatic adsorption, ion exchange, surface complexation and co precipitation, and play a role in the remediation of soil. This paper is based on Jiangxi. The tailings of Yinshan mining plant are used as the research object, using biological carbon to treat tailings, to inhibit the oxidation of tailings and to control the release of heavy metals and sulfate ions. By simulating the contaminated soil of the tailings of metal mines, the pot experiment and germination test were used to study the application of biological carbon to the contaminated soil of tailings and the growth of the plants. The main conclusions are as follows: (1) the results are as follows: (1) the pH value of soybean straw bio carbon prepared at 500 centigrade is more than 7, showing alkalinity. The Fu Liye infrared spectrum analysis shows that biological carbon contains hydroxyl, aromatic structure and acid oxygen content officer. The surface morphology of the scanning electron microscope shows that the biological carbon has a porous structure, the number of micropores is large and the shape is regular and the surface area is large. (2) through the analysis of the physical and chemical properties of copper tailings, the main components of the tailings are quartz, goethite, hematite and a small amount of gypsum, kaolinite and so on. The main elements are Fe, Al, Si and a small amount of S. The determination of heavy metals in copper tailings is that the content of Cu, Zn and Pb in copper tailings is very high, and the content of Cd is relatively low. (3) the oxidation experiment under the condition of flooding shows that hydrogen peroxide as oxidant can accelerate the oxidation of tailings, make the tailings oxidize rapidly to produce a large amount of Fe~ (3+) and SO_4~ (2-), and make the content of heavy metals in the solution obvious. Increase. In the environment of hydrogen peroxide accelerated oxidation, biological carbon still can play a good passivation effect. In the natural oxidation process, biological carbon can obviously increase the pH of tailings, inhibit the oxidation of tailings and solidify heavy metals. (4) the oxidation experiment under dry and wet conditions shows that the biological carbon can improve the soil pH in the contaminated soil of the tailings. The oxidation of soil system, inhibiting the oxidation of tailing and reducing the heavy metal content, and the synergistic treatment of biological charcoal with sodium oleate / sodium silicate in improving soil pH value, reducing oxidation, inhibiting the effect of sulphuric acid root production and passivation of heavy metals are better than biological carbon alone. Large, sodium oleate has the most obvious effect on reducing the content of sulphate root. In the polluted soil group of copper tailings, the biological charcoal is not as good as sodium oleate and sodium silicate for improving the soil pH, reducing the oxidation and inhibiting the release effect of heavy metals. In the contaminated soil group of zinc tailings, the inhibitory effect of biological carbon on heavy metals release is better than sodium oleate and sodium silicate. (5) The experiment and germination experiment showed that adding bio carbon could obviously promote the growth of the cabbage, and the effect of biological charcoal on the root growth of the cabbage was more obvious than that of the stem and leaf. The content of Cu, Zn, Pb and Cd in the tissue of the cabbage showed a positive correlation with the concentration of Cu, Zn, Pb, Cd in the soil. Biological carbon obviously reduced Cu, Zn, Pb in the cabbage. The content of Cd is obvious in passivating soil heavy metals. Biological carbon can significantly improve the pH value of contaminated soil and obviously alleviate the oxidation of sulfuric acid in sulphide minerals. In the compound heavy metal contaminated soil, biological charcoal can reduce the effect of heavy metal Pb in the plants of the cabbage. The biological carbon can reduce the toxicity of the contaminated soil to the seeds of the cabbage. The germination rate and the seedling rate of the seeds were improved.

【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X753

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