【摘要】 核工业的发展对环境造成了一定程度的铀污染,植物修复作为修复铀污染土壤的一种经济环保的方法得到广泛关注,而铀在土壤中的生物有效性是制约这一技术的关键。本文运用土壤浸取方法,研究了土壤中常见的无机阴离子对土壤中铀的解析的影响,发现CO32对铀的浸取效率在一定范围随其浓度而上升,解析率可高达85%90%;SO42的浓度从5 g/L增加到40 g/L时,铀的解析率从41%增加到53%;铀的解析率与盐析剂NaCl的浓度没有相关性;土壤质量为5 g时,解析剂体积在20 mL达到解析平衡;在浸取前3 d随浸取时间增加铀的解析率逐渐增大,105 h达到解析平衡,平衡解析率可达90%。本实验的开展有利于了解铀在土壤中的吸附-解析机制,对提高土壤中铀的生物有效性具有一定参考价值,为提高植物修复效率奠定了一定的理论基础。更多还原

【Abstract】 Background:The development of the nuclear industry caused uranium contamination to the environment.As an economical and environmental friendly technique to repair uranium contaminated soils,phytoremediation has attracted much attention in recent years,and the key to this technology is uranium bioavailability in soils.Purpose:The present work investigates the impact of several inorganic anions in soils on uranium desorption from the uranium contaminated soils.Methods:Leaching test and inductively coupled plasma-mass spectrometry(ICP-MS) was used in this study.Results:It was found that uranium desorption rate increased with CO32 concentration,and the equilibrium was obtained with resolution rate of 85% 90%.Uranium desorption rate could increase from 41% 53%when SO42 content was in the range of 5 40 g·L 1.While Cl had no effect on uranium desorption.Uranium desorption obtained equilibrium at a volume of 20 mL for strippant with 5-g uranium contaminated soil.In the former3 days,uranium desorption rate increased rapidly,and finally obtained equilibrium at 105-h with a desorption rate of90%.Conclusions:First,CO32 and SO42 have better effect on uranium desorption compared to other anions.Effect of CO32 was greater than SO42 due to a greater binding ability of CO32 to U(VI),while Cl had little effect.Second,the solvent volume and leaching time also impact uranium leaching yield.This study would be helpful to increase the knowledge of improving uranium bioavailability in the soil,which also laid a theoretical foundation to improve the efficiency of phytoremediation.更多还原