Pu在粘土岩和膨润土中的胶体行为研究

发布时间：2018-04-10 17:33

本文选题：钚 + 胶体　；参考：《西南科技大学》2017年硕士论文

【摘要】：钚本身为一种战略物资,是核武器重要的核装料,具有较强的放射性和毒性。为了获取关于钚这一放射性核素的胶体行为以及迁移机理等,本文从高庙子膨润土和内蒙阿拉善粘土岩胶体研究出发,以探究这两种天然矿物胶体在地下水中对放射性核素钚的吸附行为为目的,主要采用多种表征手段和静态吸附方法研究两种胶体对钚的吸附特征和规律,同时用铝皂石和水辉石这两种人造矿物胶体辅助对比研究,其结果如下:(1)在胶体表征方面:四种矿物在水相环境中均能形成较为稳定、分散性良好的胶体。在成分分析方面:高庙子膨润土的主要成分是蒙脱石、石英和高岭石,而胶体的主要成分为蒙脱石和高岭石,内蒙阿拉善粘土岩的主要成分是伊利石、方解石和绿泥石,而胶体的主要成分为伊利石和绿泥石,并含有微量的方解石;在结构和性质分析方面:四种矿物胶体的红外图谱基本和它们的X射线衍射结果相符。(2)四种矿物胶体吸附Pu的分配系数Kd值随着钚初始浓度的增大开始先增大,除了水辉石由于很大的比表面积,Kd值一直上升之外,其它三种矿物胶体在3×10-9g/m L-4×10-9g/m L处达到峰值后便开始降低,在此条件下胶体吸附能力阿拉善粘土岩水辉石高庙子膨润土≈铝皂石。(3)在酸性环境中,四种矿物胶体的分配系数Kd值均很低。随着pH的上升,四种矿物胶体的Kd值不断上升,在强碱性环境又开始下降。其中天然矿物胶体最适环境为中性,人造矿物胶体最适环境约为弱碱性。从pH影响结果推测出天然矿物胶体吸附钚的机理是胶体表面的羟基和钚与钚的水解产物络合。(4)离子影响实验中,Fe3+和CO2-3会减弱胶体对钚的吸附量,其中Fe3+的机理是和Pu4+的竞争作用和水解产生的酸性环境,此外Fe3+在浓度变高时会使Kd值变大,其原因可能是形成了Fe(OH)3胶体,因而Kd值的上升是由于Fe(OH)3胶体吸附钚而不是矿物胶体;CO2-3则通过络合Pu4+使Kd值急剧下降;Ca2+会使天然矿物胶体的稳定性、水合能力、膨胀性等性质增强,从而使胶体的表面基团活性增强和比表面积增大,从而使它们的吸附能力增强,此外,腐殖酸的存在会使四种矿物胶体的Kd值变大。
[Abstract]:The plutonium itself as a strategic material, is an important nuclear charge of nuclear weapons, radioactive and toxic. In order to get on the colloidal behavior of plutonium and radioactive nuclide migration mechanism, this article from the Gaomiaozi bentonite and Inner Mongolia Alashan clay colloid research starting, to explore these two kinds of natural mineral colloid adsorption the behavior of radionuclide plutonium in underground water for the purpose, mainly by the adsorption characteristics and regularity of the plutonium to study a variety of characterization methods and static adsorption method of two kinds of colloidal aluminum and water, while the two pyroxene smectite artificial mineral colloid comparative study, the results are as follows: (1) in four aspects: characterization of colloid the mineral can form more stable in aqueous environment, good dispersibility in colloid. Component analysis: the main component of Gaomiaozi bentonite is montmorillonite, quartz and kaolinite, and the main colloid Composition of montmorillonite and kaolinite, the main component of Inner Mongolia Alashan clay is illite, calcite and chlorite, and the main component of colloid illite and chlorite, and contains trace amounts of calcite; in the analysis of the structure and properties of four kinds of mineral colloid: infrared spectrum and their basic results (X ray diffraction. 2) the distribution coefficient of Kd four mineral colloid adsorption value of Pu increases with the initial concentration of plutonium began to increase, in addition to water because of pyroxene and large specific surface area, Kd value has been rising, the other three kinds of mineral colloids in 3 * 10-9g/ m L-4 * 10-9g/m L at the peak and began to decrease, under this condition colloid adsorption capacity of Alashan clay rock hectorites GMZ-1 is aluminum smectite. (3) in the acidic environment, the distribution coefficient of Kd four mineral colloid values were very low. With the increase of pH, four kinds of mineral colloid Kd wasvalues Rise in the strong alkaline environment began to decline. The natural mineral colloid optimum environment for neutral, artificial mineral colloid optimum environment about weak alkaline. From pH results that the mechanism of the natural mineral colloid adsorption of plutonium is colloid surface hydroxyl groups and the hydrolysis product of plutonium and plutonium complex. (4) ion effect in the experiment, Fe3+ and CO2-3 will weaken the adsorption of colloids on plutonium, which is the mechanism of Fe3+ and Pu4+ acidic environment due to the competition and the hydrolysis of Fe3+ in high concentration, in addition to the Kd value becomes large, probably due to the formation of Fe (OH) 3 colloid, Kd value is rising so the Fe (OH) 3 colloid adsorption plutonium rather than mineral colloid; CO2-3 through complex Pu4+. Kd value decreased sharply; Ca2+ will make the stability of natural mineral colloid hydration ability, swelling properties increased, so that the active surface groups of colloid enhancement and specific surface area increased, In addition, the presence of humic acid will increase the Kd value of the four mineral colloids.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.353;O648.1

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