无机锶吸附剂的制备及其应用

摘要

为了去除放射性溶液中的90 Sr,采用高锰酸钾和氯化锰的水溶液在 pH=10~12、60℃的水浴中反应制备了一种 MnO2吸附材料,并用 X 射线衍射法对其进行了初步分析和表征,该样品为α-MnO2和γ-MnO2的混合晶相。采用静态实验对该吸附剂进行研究,并将其与9种常见的天然锶吸附材料进行比较。结果表明：该吸附剂对90 Sr 的吸附效果明显好于常用天然吸附材料；其对90 Sr 的吸附速率非常快,约20 min 即可吸附平衡,且具有较高的理论饱和吸附容量(Q≈0.52 mmol/g)和吸附分配系数(Kd ),其典型 Kd ≈104 mL/g；随着硝酸浓度增加90 Sr 的 Kd 值迅速降低,当 c(HNO3)=0.01 mol/L 时,Kd ≈6×103 mL/g,而当 c(HNO3)=0.1 mol/L时,Kd 值仅为6 mL/g,降低了3个数量级；Na+、K+的含量对 Kd 值的影响较小,随其浓度增加 Kd 值缓慢降低,但 Co2+、Ca2+对锶的 Kd 值具有较大的影响,随离子浓度增加 Kd 值快速减小。该吸附剂对模拟和真实放射性废液的90 Sr 动态去除实验结果表明,其对锶具有很好的吸附性能,可用于去除放射性废水中的90 Sr。%In order to remove 90 Sr from the liquid radioactive waste,a novel of inorganic adsorbent MnO2 was prepared through the reaction of potassium permanganate with manga-nese chloride in the pH=10-12 aqueous solution,under the 60 ℃ water bath condition.The material sample was characterized and analyzed by X-ray diffraction method.The adsorbent was studied through the static experimental test in details,and compared with several common natural strontium sorption materials.The results indicate that the adsorption effect of the adsorbent for 90 Sr is obviously better than those of other sorption materials.The adsorption rate of the adsorbent for 90 Sr is very fast,and the adsorption can reach equilibri-um in about 20 min.The adsorbent has high theoretical saturated adsorption capacity (Q=0.52 mmol/g)and distribution coefficient (K d ).The typical K d value is about 10 4 mL/g. The influence of HNO3 ,Na+ ,K+ ,Co2 + and Ca2 + concentration on the adsorption for 90 Sr were studied in this paper.The results show that the K d value decreases rapidly with increasing the concentration of HNO3 ,when the concentration of nitric acid is 0.01 mol/L, and the K d value is about 6×10 3 mL/g.When the concentration of nitric acid is 0.1 mol/L,the K d value is only 6 mL/g yet,that reduces 3 orders of magnitude.The content of mono-valnet cations Na+ ,K+ have little effect on the K d value.While the two divalent cations Co2 + ,Ca2 + have great influence on the K d value,it rapidly decreases with the increase of ion concentration.At last,the adsorbent was used to remove the 90 Sr in the simulated and real radioactive waste liquid by dynamic experiments respectively.The results prove that the adsorbent has excellent adsorption performance for strontium,and it has good application prospect on the removal of 90 Sr from radioactive waste liquid.