重金属污染土壤化学淋洗修复机理的研究
毕业论文关键词：土壤团聚体；重金属；化学淋洗
Study on the Effect of the Reduction of Heavy Metal in Contaminated Soils by Chemical Washing
Abstract：In recent years, the problem of heavy metal pollution of soil in China is becoming increasingly serious, heavy metals Pb, Hg, Cr, Cu and the compound through the food chain in vivo enrichment, has posed a serious threat to soil quality, the quality of agricultural products and human health. At present, the methods for remediation of soil heavy metals pollution are physical, chemical, biological and combined remediation methods.This paper selected Qixia, Shaoguan, soil samples from Chang An three, to study the leaching before and after soil nutrients and heavy metal content changes; different forms of the three BCR extraction method for leaching and three soil samples in aggregates of heavy metals (acid soluble and reducible, oxidizable and residual) the major elements were extracted; leaching in the soil samples dissolution were analyzed with Fe and Al elements; an inquiry after washing free, non crystalline, complex state of three kinds of changes. Through these four aspects, we simply explore the mechanism of chemical leaching remediation of heavy metal soil. The results show that with the decrease of the size of soil particles, heavy metals and nutrient content of soil aggregates to clay enrichment increased; 100 mmol•L-1 +20 mmol•L-1 FeCl3 citric acid leaching of composite soil samples, Pb, Cd, Zn and Cu four kinds of heavy metals in the highest removal rate than the single use of citric acid the leaching rate increased by 31.83%, than the single FeCl3 leaching rate increased by 24.07%;The leaching rates of heavy metals Pb, Cd, Zn and Cu are coarse silty sand grade > silty sand grade > sand particle grade > clay grade.
Key words: soil aggregate;heavy metal;chemical washing
目 录
摘要1
关键词1
Abstract1
Key words1
引言 1
1材料与方法 2
1.1实验土样 2
1.2所用试剂及仪器 3
1.3重金属分级形态的测定 3
1.4淋洗液中的金属离子的测定3
1.5土壤团聚体的淋洗4
1.6数据处理 4
2 实验结果分析4
2.1土样团聚体的组成4
2.2淋洗效果与淋洗率 6
2.3土样团聚体中重金属的形态变化及形态分分析 7
3 总结 11
致谢11
参考文献12
重金属污染土壤化学淋洗修复机理的研究
引言
近年来，随着工农业的迅速发展,环境污染和生态破坏日益严峻，严重影响到了人类的健康和生存，其中重金属元素对环境的污染和破坏作用尤为严重，特别是Pb、Hg、Cr、Cu及其复合污染最为突出。污水的农田灌溉、污泥的农业利用、畜禽废弃物和无机肥料的施用皆会导致了部分土壤被重金属污染，同时土壤肥力退化，作物产量和品质降低[1]。且土壤中的重金属可以通过食物链在生物体内进行富集[2]，土壤中重金属元素的化学形态及其与土壤物质的结合形式是影响其迁移活动性和生物可利用性的主要原因。重金属在土壤中可被土壤组分如：土壤黏粒、土壤中的有机质等吸附在表面；也可与土壤矿物质如：与土壤矿物如碳酸盐、铁氧化合物、硫化物等结合形式存在[3]。重金属的生物毒性不仅与环境中所含重金属含量的多少有关，还与其形态分布有很大关系。不同的形态会产生不同的环境效应，可以直接影响到重金属的毒性、在环境中的迁移与与其在自然界的循环[4]。
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