东江湖铅锌矿渣堆场土壤重金属污染评价及治理方法研究

发布时间：2018-01-09 06:02

本文关键词：东江湖铅锌矿渣堆场土壤重金属污染评价及治理方法研究　出处：《湘潭大学》2015年硕士论文　论文类型：学位论文

【摘要】：重金属污染土壤对东江湖生态环境造成严重威胁,本研究沿东江湖铅锌矿渣堆场共布置71个具有代表性的采样点,对土壤中的Pb、Zn、Cu、Cd和As五种重金属含量及其pH进行了测定分析,并选用地积累指数法、环境容量法和潜在生态风险法对渣场分别进行土壤重金属污染风险评价。在此基础上,针对重金属污染土壤进行淋洗处理和稳定化的小试研究,采用草酸、柠檬酸、EDTA和茶皂素进行土壤重金属淋洗实验,确定最佳淋洗剂、淋洗浓度、淋洗时间和液土比。同时,采用骨炭、氧化钙、硫化钠、过磷酸钙、二乙基二硫代氨基甲酸钠、硫酸亚铁等不同类型的稳定剂进行土壤重金属稳定化实验,考察单一稳定剂和组配稳定剂对土壤重金属的稳定效果,并确定最佳单一稳定剂及其投加量、最佳组配稳定剂及其组配比例。研究所得主要结果如下:(1)东江湖铅锌矿渣堆场土壤中各重金属平均含量分别为湖南省土壤背景值的64、3.6、5.5、18.5、7.6倍;根据超标倍数排序为PbCdAsCuZn,对地积累指数平均值进行排序为PbCdAsCuZn,对环境容量评价结果平均值进行排序为:PbCdAsCuZn,对潜在生态风险平均值进行排序为:CdPbAsCuZn。堆场土壤重金属污染最为严重区域主要集中在矿渣原堆放点,即堆场的东北部、中部和西南部。(2)实验得到草酸为最佳淋洗剂,其对Pb、Zn、Cu、Cd和As均有较好的淋洗效果。最佳淋洗条件为:淋洗浓度为0.2 mol/L、淋洗时间为10h、淋洗液土比为25:1。在优化实验条件下,对Pb、Zn、Cu、Cd和As等重金属的去除率分别为38.45%、39.33%、39.66%、34.61%、35.24%。(3)根据单一稳定剂综合稳定率可知,氧化钙的综合稳定效果最好,其投加量为3g/100g时,土壤中Pb、Zn、Cu、Cd和As的稳定率分别为73.82%、38.11%、75.00%、42.94%和57.69%。(4)根据组配稳定剂综合稳定率可知,最佳组配稳定剂为稳定剂A(骨炭、硫化钠),其最佳组配比例为3:1,对土壤中的Pb、Zn、Cu、Cd和As均有良好的稳定效果,其稳定效率分别为99.05%、84.41%、64.29%、81.76%和11.54%。SEM表征结果表明,处理后土壤表面相对粗糙并出现部分结晶体,且形成了针状或棒状结晶,从而使得重金属离子难以浸出,形成稳定的固态体。
[Abstract]:The soil heavy metal pollution poses a serious threat to the ecological environment of the eastern lakes, rivers and lakes along the east yard layout is lead-zinc slag 71 representative samples, the soil Pb, Zn, Cu, Cd and As five kinds of heavy metal content and pH were analyzed, and the accumulation index method, environmental capacity and the potential ecological risk method of slag field is used to evaluate the risk of heavy metal pollution of soil. On the basis of laboratory study, washing treatment and stabilization for heavy metal contaminated soil using oxalic acid, citric acid, EDTA and tea saponin of soil heavy metal leaching experiment, determine the optimal eluent, elution concentration, leaching time and liquid soil. At the same time, the use of bone char, calcium oxide, sodium sulfide, calcium superphosphate, two ethyl two sodium dithiocarbamate stabilizer, ferrous sulfate and other different types of heavy metals in the soil of experimental stability, stable single study The effect of stabilizer and stability with stabilizer on heavy metals in the soil, and to determine the optimal single stabilizer and its dosage, the best combination of stabilizer and its combination ratio. The experimental results were summarized as follows: (1) the average content of heavy metals in soil in Dongjiang Lake lead-zinc slag yard were 64,3.6,5.5,18.5,7.6 times of the soil background value of Hunan province; according to the exceed the standard multiple ranked PbCdAsCuZn, the accumulation index average of the order of PbCdAsCuZn, ranking for average value of environmental capacity evaluation results: PbCdAsCuZn, as a sort of average value of the potential ecological risk of soil heavy metal pollution: CdPbAsCuZn. yard is the most serious areas are mainly concentrated in the original slag stacking yard, namely the northeast, central and the southwest. (2) the best oxalic acid as eluent, the Pb, Zn, Cu, Cd and As have better effect. The optimum conditions for leaching leaching: leaching concentration For 0.2 mol/L, the leaching time is 10h, the eluent is 25:1. ratio under the optimized experimental conditions, the Pb, Zn, Cu, Cd and As and other heavy metal removal rates were 38.45%, 39.33%, 39.66%, 34.61%, 35.24%. (3) according to the comprehensive stability rate of single stabilizer, the best comprehensive stabilization effect of calcium oxide, the dosage of 3g/100g, Pb in soil, Zn, Cu, Cd and As stable rates were 73.82%, 38.11%, 75%, 42.94% and 57.69%. (4) according to the group with stable rate of the integrated stabilizer stabilizer, A is the best combination of stabilizer (char, sodium sulfide), the best group the ratio of 3:1 to Pb in soil, Zn, Cu, Cd and As have good effect of stability, the stable rate was 99.05%, 84.41%, 64.29%, 81.76% and 11.54%.SEM. The results showed that after treatment, the soil surface is relatively rough and some crystals, and the formation of a needle or rod shape, which makes the from the heavy metal The seed is difficult to leach to form a stable solid.

【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X825

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