离子型稀土矿区土壤中稀土元素对氮化物影响与作用研究
发布时间：2019-06-06 16:52
【摘要】：针对赣南稀土矿区稀土矿开采造成土壤氮化物污染的问题,为了探索土壤氮化物污染与稀土元素间的联系,论文以稀土矿区原矿土壤为研究对象,制作土柱装置,先通过模拟降雨的淋滤实验来探究内源性稀土元素对土壤中氮化物分布特征影响;再采取向原矿土壤中添加不同种类和不同浓度的外源稀土元素,进行稀土元素对上下层土壤氮化物含量的影响研究;最后阐述了稀土元素和氮化物两者间的作用机理及氮化物的转化机理。得出以下结论:(1)在淋洗水流的冲刷下,铵态氮在原矿土壤中土柱各深度的淋失量为500 mg/kg左右,而在校园土壤各深度的淋失量为350-1300 mg/kg,在原矿土壤中的铵态氮淋失量明显大于原矿土,这是因为原矿土壤中稀土元素的存在加强了土壤的固氮能力;而硝态氮在原矿土中的迁移速率和迁移量要大于校园土壤。(2)总结添加不同浓度的氧化钇、氧化镧以及混合稀土对上下层土壤铵态氮含量的影响特征:“低促高抑”,即低浓度外源稀土对土壤铵态氮含量表现为促进作用,而高浓度则表现为抑制作用。确定对铵态氮含量值影响较大的添加氧化钇浓度的峰值在5-10 g/kg之间,添加氧化镧浓度的峰值在0-1 g/kg之间,添加混合稀土浓度的峰值在在0-1 g/kg之间。(3)添加不同浓度的氧化钇对上下层土壤硝态氮含量影响不显著,添加氧化镧则对上下层土壤硝态氮含量表现为抑制作用,而添加不同浓度的混合稀土对上下层土壤的硝态氮含量仍表现出“低促高抑”的特点。(4)在添加不同浓度的氧化钇、氧化镧以及混合稀土条件下,无论是上层还是下层土壤,有效氮含量随时间变化的趋势与铵态氮几乎一致,这是因为一方面原矿土壤中有机质含量较低,另一方面则是由于浸取剂硫酸铵残留于土壤中,土壤中铵态氮含量远远高于硝态氮和其他形态氮化物总和,铵态氮为有效氮的主要表现形式。(5)稀土元素与氮化物作用的机理主要是稀土离子与铵根离子的交换解析作用,生成络合物。而氮化物本身在外界条件下也会发生转化,稀土元素的加入可能会影响其转化途径和转化速率。
[Abstract]:In view of the problem of soil nitride pollution caused by rare earth mining in southern Jiangxi rare earth mining area, in order to explore the relationship between soil nitride pollution and rare earth elements, this paper takes the raw ore soil of rare earth mining area as the research object, and makes the soil pillar device. Firstly, the effect of endogenous rare earth elements on the distribution of nitride in soil was studied by the leaching experiment of simulated rainfall. Then different kinds and concentrations of exogenous rare earth elements were added to the raw ore soil to study the effect of rare earth elements on the nitride content in the upper and lower soils. Finally, the interaction mechanism between rare earth elements and nitride and the transformation mechanism of nitride are described. The conclusions are as follows: (1) under the scour of leaching flow, the leaching loss of ammonium nitrogen in each depth of soil column in raw ore soil is about 500 mg/kg, while that in campus soil is 350 鈮，
本文编号：2494454
[Abstract]:In view of the problem of soil nitride pollution caused by rare earth mining in southern Jiangxi rare earth mining area, in order to explore the relationship between soil nitride pollution and rare earth elements, this paper takes the raw ore soil of rare earth mining area as the research object, and makes the soil pillar device. Firstly, the effect of endogenous rare earth elements on the distribution of nitride in soil was studied by the leaching experiment of simulated rainfall. Then different kinds and concentrations of exogenous rare earth elements were added to the raw ore soil to study the effect of rare earth elements on the nitride content in the upper and lower soils. Finally, the interaction mechanism between rare earth elements and nitride and the transformation mechanism of nitride are described. The conclusions are as follows: (1) under the scour of leaching flow, the leaching loss of ammonium nitrogen in each depth of soil column in raw ore soil is about 500 mg/kg, while that in campus soil is 350 鈮，
本文编号：2494454
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