Sr、Cs在碱矿渣-粘土复合水泥水化物粉体中的吸附行为

Adsorption Behavior of Sr and Cs in Hydrated Paste Powder of Alkai-activated Slag-clay Minerals Composite Cement

水泥的水化物对核素离子吸附性能将影响水泥固化体对核素离子固化性能。应用静态吸附法研究碱矿渣-粘土复合水泥(AASCM)水化物粉体对模拟放射性核素Sr、Cs的吸附性能及其影响因素,并和硅酸盐水泥(PC)、铝酸盐水泥(AC)、矿渣硅酸盐水泥(PSC)、碱矿渣水泥(AASC)进行对比。结果表明,实验条件下,母液浓度提高,AASCM水化物粉体对Sr、Cs的吸附量增大,吸附比减小;温度升高,吸附平衡时间缩短,吸附量和吸附比下降。Cs在AASCM粉体中的吸附在一定的浓度范围内服从Freudlich吸附等温方程;AASCM水化物粉体与Sr2+的作用在母液浓度较大时存在吸附和沉淀双重机制,与Cs+的作用则主要是吸附机制;AASCM水化物粉体较PC、AC、PSC、AASC具有更强的吸附能力。

The adsorption capacity of hydrated cement to radio nuclides has an influence on the solidified performance of radio nuclides in the waste forms. The adsorption of simulated radio nuclides Sr and Cs in hydrated paste powder of alkali-activated slag-clay minerals composite cement（AASCM） was studied by means of static adsorption method and a comparison with those of Portland cement（PC）, aluminate cement（AC）, Portland blast-furnace slag cement（PSC） and alkali-activated slag cement（AASC） was made. The results showed that, under the experimental conditions, the adsorption capacity of Sr and Cs in hydrated paste powder of AASCM increases and adsorption ratio decreases with initial concentration of Sr^2＋ and Cs^＋. The adsorption equilibrium time shortens and the adsorption capacity and ratio decrease with temperature, In a certain range of Cs concentration, the adsorption isothermal curve of Cs in hydrated paste powder of AASCM is in conformity to Freudlich formula. The action mechanism of hydrated paste powder of AASCM with Sr^2 ＋ includes both adsorption and precipitation at higher initial concentration while there is only adsorption with Cs^＋ . The adsorption of Cs in hydration paste powder of AASCM is more powerful than that of PC, AC, PSC and AASC.