Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
J Environ Radioact. 2013 Jan;115:143-50. doi: 10.1016/j.jenvrad.2012.08.006. Epub 2012 Aug 30.
In this paper, the adsorption and desorption behavior of uranium (VI) in aerated zone soil (from Southwest China) was systematically investigated using a static experimental method in order to provide useful information for safety assessment of the disposal of (ultra-)low uraniferous radioactive waste, as well as a potential remediation method for uranium-contaminated soils. The adsorption behavior of uranium (VI) was firstly studied by batch experiments as functions of contact time, pH, liquid/solid ratio, temperature, colloids, minerals and coexistent ions. The results indicated that the adsorption of uranium (VI) by natural soil was efficient at an initial concentration of 10 mg/L uranium (VI) nitrate solution with 100 mg natural soil at room temperature when pH is about 7.0. The adsorption was strongly influenced by the solution pH, contact time, initial concentration and colloids. The adsorption equilibrium for uranium (VI) in soil was obtained within 24 h and the process could be described by the Langmuir adsorption equation. For uranium (VI) desorption, EDTA, citric acid and HNO(3) were evaluated under different conditions of temperature, concentration and proportion of liquid to solid. The adsorbed uranium (VI) on natural soil could be easily extracted by all these agents, especially by HNO(3), implying that the uranium-contaminated soils can be remedied by these reagents.
本文采用静态实验方法系统研究了有氧带土壤（来自中国西南地区）中铀（VI）的吸附和解吸行为，以期为（超）低放贫铀废物处置的安全评估提供有用信息，以及铀污染土壤的潜在修复方法。首先通过批实验研究了铀（VI）的吸附行为，考察了接触时间、pH 值、液固比、温度、胶体、矿物和共存离子等因素的影响。结果表明，在室温下，初始浓度为 10mg/L 的硝酸铀酰溶液中用 100mg 天然土壤处理时，天然土壤对铀（VI）的吸附在初始浓度为 10mg/L 时效率较高，pH 值约为 7.0。吸附强烈受溶液 pH 值、接触时间、初始浓度和胶体的影响。土壤中铀（VI）的吸附平衡在 24 小时内达到，吸附过程可以用朗缪尔吸附方程描述。对于铀（VI）的解吸，在不同的温度、浓度和液固比条件下评价了 EDTA、柠檬酸和 HNO3 的效果。天然土壤上吸附的铀（VI）可以很容易地被所有这些试剂提取，特别是 HNO3，这意味着这些试剂可以修复铀污染的土壤。
