某地核废物填埋区土壤的表面电荷及矿物组成对核素锶吸附的影响

THE EFFECT OF SUPERFICIAL CHARGE AND MINERAL COMPONENT OF SOIL ON NUCLIDE STRONTIUM'S ADSORPTION IN SOME RADWASTE BARRIER

为了降低放射性废物的危害,一般采取就地填埋的处置技术。影响核素锶吸附的因素针对吸附的基础物料土壤来说,主要有表面电荷、矿物组成;而外界环境因素如添加剂,对核素的吸附比也有很大影响。实验采用静态吸附的方法,通过测定核素锶的浓度,求得不同土壤对核素锶的吸附比,进而判断出应选用哪种物料吸附核素。实验结果表明,该地核废物填埋区的不同土壤,表面电荷中的正、负电荷均发育,但负电荷相对于发育的土壤而言对锶的吸附比偏大。矿物组成中以石英为主,但也含有一些吸附性强的粘土矿物(如蒙脱石、伊利石等)。实验最后选定的棕黑色砂质粉土TY29,在加入适量的添加剂碳酸钠后,吸附系数可达103数量级,满足工程屏蔽的要求。

In order to reduce the pollution of radwaste,we usually adopt fill-in method near the radwaste.The factor that affect the adsorption of Strontium has superficial charge,mineral component,and besides the outer factor,such as additive also has impact on it.In this article,experiment static adsorption is adopted,and through measuring the concentration of Strontium to acquire the adsorption ratio of different soils for selecting the best adsorption material.The outcome of experiment indicates that although different soil superficial charge in nuclide waste barrier contain positive and negative charges,the soil that contain more negative charge has the higher adsorption ratio;And in the mineral component's quartz is primary,and it is,however,also composed of some strong adsorption minerals,such as montmorillonite,illite.The brown arenaceous powder TY29 joined with sodium carbonate had the highest Kd(103) content,which meets the need of barrier.For the other factors that affect adsorption need further validation.