稀土在包头尾矿库区土壤中的吸附及迁移试验研究
发布时间：2018-09-19 14:07
【摘要】：包头尾矿中的稀土元素在雨水淋洗和渗流作用下会溶解浸出并进入地表及地下水体系中,然后发生迁移,对周围环境造成极大的危害,进而影响到人类的健康。因此定量分析尾矿库区污染物在环境中的吸附和迁移特征,预测不同地址环境下污染物的迁移过程,对进行污染物防治的规划、设计、施工、尾矿坝的正常运行、保护周边环境具有十分重要的意义。本文采用包头尾矿库周边土壤作为吸附介质,首先以静态吸附法研究了尾矿库区土壤对La3+的吸附,明确了包头尾矿库区土壤对La3+的吸附特征及腐殖酸、温度、pH和共存阳离子对La3+吸附的影响；其次采用脉冲注射模拟土壤柱迁移实验研究了土壤对La3+的动态吸附和迁移,明确了La3+的浓度、淋洗液pH值、溶液共存离子及腐殖酸胶体对迁移的影响。主要研究结果如下：1、土壤对La3+的静态吸附试验表明：该地区土壤对稀土元素的等温吸附过程用Freundlich吸附方程描述最佳,该吸附属于非均相吸附；吸附动力学符合准二级动力学方程,线性相关系数在0.9998以上；当pH小于4时,吸附作用随溶液pH的增大而迅速增大,当pH大于4时,吸附作用随溶液pH值增加的趋势减缓；吸附量随温度升高而增大,说明土壤对稀土元素的吸附是一个吸热过程；吸附过程也受到共存阳离子的影响,共存阳离子会抑制土壤对La3+吸附,影响结果为：Ca2+Fe3+Na+;腐殖酸可以促进土壤在不同影响因素下对镧离子的吸附。由于不同腐殖酸内部所含的酸性基团大小及芳香度不同,所以对镧离子吸附的促进程度不同。2、土壤对La3+的动态迁移实验结果表明：不同注射浓度的BTC曲线均在130s上达到最高峰。注射浓度为260μg/ml时具有相对较好对称性；该地区土壤的有效孔隙度为0.64,滞留因子Rd=0.1985；分配系数Kd=0.1794m L.g-1；pH=4-7穿透总时间较pH=8、9短,说明酸性条件下可以促进La3+在尾矿土壤中的迁移；Na+对La3+的迁移影响是先增大后减小,然后保持不变,在150μg/ml处取得最大；Ca2+浓度对La3+的迁移影响是随着钙离子浓度增大程直线上升趋势；HA的存在可促进La3+在土壤柱中的迁移。
[Abstract]:The rare earth elements in Baotou tailings will be dissolved and leached into the surface and groundwater system under the action of Rain Water leaching and seepage, and then migrated, which will cause great harm to the surrounding environment and affect human health. Therefore, quantitative analysis of the adsorption and migration characteristics of pollutants in the tailings reservoir area, prediction of pollutant migration process in different address environments, planning, design, construction and normal operation of tailings dam are carried out. It is of great significance to protect the surrounding environment. In this paper, the soil around Baotou tailings reservoir was used as the adsorption medium. Firstly, the adsorption of La3 on the soil was studied by static adsorption method, and the adsorption characteristics of La3 and humic acid in the soil of Baotou tailing reservoir were determined. The effects of temperature, pH and co-existing cations on the adsorption of La3 were studied. Secondly, the dynamic adsorption and migration of La3 to soil were studied by means of pulse-injection simulated soil column migration experiments. The concentration of La3 and the value of pH in leaching solution were determined. Effects of solution coexisting ions and humic acid colloid on migration. The main results are as follows: 1. The static adsorption experiment of La3 on soil shows that the isothermal adsorption process of rare earth elements in this area is best described by Freundlich adsorption equation, and the adsorption belongs to heterogeneous adsorption. The adsorption kinetics accords with the quasi-second-order kinetic equation, the linear correlation coefficient is more than 0.9998, when pH is less than 4, the adsorption increases rapidly with the increase of pH, and when pH is greater than 4, the adsorption decreases with the increase of pH value. The adsorption amount increased with the increase of temperature, indicating that the adsorption of rare earth elements in soil was an endothermic process, and the adsorption process was also affected by coexisting cations, which inhibited the adsorption of La3 to soil, and the result was Ca 2 / Fe3 Na. Humic acid can promote the adsorption of lanthanum ions in soil under different influence factors. Because of the different acidity group size and aromaticity in different humic acid, the promotion degree of lanthanum ion adsorption was different. The dynamic migration experiment of soil to La3 showed that the BTC curve of different injection concentration reached its peak at 130s. When the injection concentration was 260 渭 g/ml, the effective porosity of soil in this area was 0.64, and the Rd=0.1985; partition coefficient of Rd=0.1985; was shorter than that of pH=8,9, which indicated that the transport of La3 in tailings soil could be promoted under acidic conditions. The effect of Na on La3 migration was first increased and then decreased, and then remained unchanged. The effect of maximum Ca 2 concentration on La3 migration at 150 渭 g/ml was that the existence of HA could promote the migration of La3 in soil column with the increase of Ca 2 + concentration in a straight line.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X753
本文编号：2250352
[Abstract]:The rare earth elements in Baotou tailings will be dissolved and leached into the surface and groundwater system under the action of Rain Water leaching and seepage, and then migrated, which will cause great harm to the surrounding environment and affect human health. Therefore, quantitative analysis of the adsorption and migration characteristics of pollutants in the tailings reservoir area, prediction of pollutant migration process in different address environments, planning, design, construction and normal operation of tailings dam are carried out. It is of great significance to protect the surrounding environment. In this paper, the soil around Baotou tailings reservoir was used as the adsorption medium. Firstly, the adsorption of La3 on the soil was studied by static adsorption method, and the adsorption characteristics of La3 and humic acid in the soil of Baotou tailing reservoir were determined. The effects of temperature, pH and co-existing cations on the adsorption of La3 were studied. Secondly, the dynamic adsorption and migration of La3 to soil were studied by means of pulse-injection simulated soil column migration experiments. The concentration of La3 and the value of pH in leaching solution were determined. Effects of solution coexisting ions and humic acid colloid on migration. The main results are as follows: 1. The static adsorption experiment of La3 on soil shows that the isothermal adsorption process of rare earth elements in this area is best described by Freundlich adsorption equation, and the adsorption belongs to heterogeneous adsorption. The adsorption kinetics accords with the quasi-second-order kinetic equation, the linear correlation coefficient is more than 0.9998, when pH is less than 4, the adsorption increases rapidly with the increase of pH, and when pH is greater than 4, the adsorption decreases with the increase of pH value. The adsorption amount increased with the increase of temperature, indicating that the adsorption of rare earth elements in soil was an endothermic process, and the adsorption process was also affected by coexisting cations, which inhibited the adsorption of La3 to soil, and the result was Ca 2 / Fe3 Na. Humic acid can promote the adsorption of lanthanum ions in soil under different influence factors. Because of the different acidity group size and aromaticity in different humic acid, the promotion degree of lanthanum ion adsorption was different. The dynamic migration experiment of soil to La3 showed that the BTC curve of different injection concentration reached its peak at 130s. When the injection concentration was 260 渭 g/ml, the effective porosity of soil in this area was 0.64, and the Rd=0.1985; partition coefficient of Rd=0.1985; was shorter than that of pH=8,9, which indicated that the transport of La3 in tailings soil could be promoted under acidic conditions. The effect of Na on La3 migration was first increased and then decreased, and then remained unchanged. The effect of maximum Ca 2 concentration on La3 migration at 150 渭 g/ml was that the existence of HA could promote the migration of La3 in soil column with the increase of Ca 2 + concentration in a straight line.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X753
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