Eu(III)在北山花岗岩上的吸附作用  

The adsorption of Eu(III) on Beishan granite

作　　者：郭治军[1,2] 陈宗元[2] 吴王锁[2] 刘春立[1] 陈涛[1] 田文宇[1] 黎春[1] 

机构地区：[1]北京分子科学国家实验室北京大学化学与分子工程学院,北京100871 [2]兰州大学核科学与技术学院,兰州730000

出　　处：《中国科学：化学》2011年第5期907-913,共7页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(10775008&20971061);教育部博士点基金(20060001032);国防科工委军工遗留专项基金(科工计[2007]840);中央高校基本科研业务费专项资金;北京大学测试基金(第13–18期)资助

摘　　要：用电位滴定法研究了甘肃北山花岗岩(BS03,600m)的酸、碱性质,用批式法研究了Eu(III)在该花岗岩上的吸附行为.实验结果表明:在离子强度I=0.1M的NaCl溶液中,北山花岗岩的pHPZNPC为9.4,当I增大至0.4M时,pHPZNPC为9.0.不同离子强度下花岗岩的电位滴定曲线与类似条件下蒙脱石的相仿.Eu(III)在北山花岗岩上的吸附分配比(Kd)随pH、离子强度和Eu(III)浓度的变化而变化.在低pH范围,Eu(III)的Kd值随离子强度的增大显著减小,而在高pH值范围,离子强度对Kd的影响甚微.用模型定量解释了Eu(III)在北山花岗岩上的吸附随pH、离子强度和Eu(III)浓度而变化的实验数据,该模型包含Eu3+与花岗岩发生的阳离子交换反应以及Eu(III)与花岗岩表面羟基发生两个内层表面配合反应(inner-sphere surface complexation reactions).用所建模型对离子强度为0.1M时Eu(III)在北山花岗岩上的吸附行为作了预测,并与文献报道的类似条件下Am(III)在北山花岗岩上的吸附实验数据作了比较.The acid-base chemistry of Beishan （Gansu, China） granite （BS03, 600 m） was studied by potentiometric titration, and the adsorption of Eu（III） on the granite was investigated using a batch technique. It was found that the pHPZNPC of the granite is 9.4 at I = 0.1 M NaCl and decreases to 9.0 at I = 0.4 M NaCl. The profile of parallel titration curves of the granite at variable ionic strengths is roughly comparable to that of montmorillonite under similar conditions. The distribution coefficient （Kd） of Eu（III） on the granite varies with pH, ionic strength and Eu（III） concentration. The Kd values of Eu（III） decrease significantly with increasing ionic strength in the low pH range, whereas the effect of ionic strength on the Kd values is very weak in the high pH range. The experimental results of Eu（III） adsorption on the granite as a function of pH, ionic strength and Eu（III） concentration were quantitatively interpreted by a model with a cation exchange reaction of Eu3＋ on the granite and two inner-sphere surface complexation reactions of Eu（III） on the surface hydroxyl sites. The adsorption of Eu（III） on the granite at I = 0.1 M was predicted by the proposed model, which was compared with the results of Am（III） adsorption on the granite under similar conditions reported by other groups.

关 键 词：北山花岗岩 吸附 EU(III) 表面配位 构模 

分 类 号：P588.121[天文地球—岩石学]