| 镉在土壤中吸附与沉淀的特征与界限 |
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| 引用本文：费宇红,曹树堂,张光辉,聂振龙.1998.镉在土壤中吸附与沉淀的特征与界限[J].地球学报,19(4):409-414. |
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| 中文摘要:吸附和沉淀反应虽然是不同范畴的概念，但是，二者彼此依存，相互作用和制约，二者界限除考虑体系中Ｃｄ量和环境ｐＨ，Ｅｈ等因素外「ＣＯ＾２－３」／「ＯＨ＾－」关系及其质量浓度也是重要因素。在酸性条件下，吸附反应起主控作用；在碱性条件下，沉淀反应起主控作用；在ｐＨ介于６．５－８．５范围，吸附与沉淀综合利用效果最强。 |
| 中文关键词:Cd 包气带 吸附与沉淀 特征 界限 |
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| Characteristics and Boundary Line between Adsorption and Precipition of Cadmium in Soil |
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| Abstract:Based on a comparison between the experimental results and previous test results, the authors consider that the adsorption forms of soil adsorbing cadmium from soil solution are Freundlich's forms in unsaturated zone under the condition of pH = 6.5～11.5 and that the remnant speciation is the main form of cadmium existing in the unsaturated soil,formulae have been set up for the relationship between unit time adsorption content of cadmium from soil solution and soil solution concentration of cadmium, and between adsorption content and the concentration in each process of adsorbing cadmium by soil from soil solution; It is also held that the adsorption dominantly controls soil solution concentration of cadmium under the acid condition, the precipitation controls it under the alkaline condition, and the adsorption together with the precipitation control cadmium concentration under pH=6.～8.5 . In general, the relationship between the dissolution and the precipitation of CdCO 3-CO 2-pH or Cd(OH) 2-CO 2-pH controls the concentration of cadmium in soil, but the relationship between the adsorption and pH of soil solution controlls the concentration under the condition that the soil solution concentration of cadmium is lower than its critical concentration of the precipitation. The boundary line between the adsorption and the precipitation, which dominantly control the concentration of soil solution, is preliminarily established, which is at about 10 -8 (pH=8.5) ～10 -4 mol/L (pH=4.5), based on the condition of soil pH and p CO 2 in China and on the research results of this paper. |
| keywords:cadmium unsaturated zone asorption and precipition characteristics boundary line |
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