错流超滤技术在海水胶体态铀、钍、镭同位素和有机碳研究中的应用  

Application of the cross-flow ultrafiltration technique to the study of colloidal uranium, thorium, radium isotopes and organic carbon in seawater

作　　者：陈敏[1] 郭劳动[2] 黄奕普[1] 高众勇[1] 蔡毅华[1] 蔡明刚[1] 

机构地区：[1]厦门大学海洋系,厦门361005 [2]Department of Oceanography, Texas A& M University, 5007 Avenue U, Galveston

出　　处：《海洋学报》2000年第5期51-59,共9页

基　　金：国家自然科学基金!(编号:49706069);国家自然科学基金!(98-美014)

摘　　要：建立了由预过滤装置、蠕动泵、中空纤维超滤膜（Ａｍｉｃｏｎ Ｈ１０Ｐ１０－２０，标 称截留分子量 １０ ＫＤａ）和连接管组成的错流超滤系统，利用荧光标记的 ４０ ＫＤａ葡聚 糖和已知放射性活度的２３４Ｔｈ示踪剂评估了超滤膜的截留和吸附性质，探讨了２３４Ｔｈ 在超滤过程中的渗透行为，考查了该系统用于实际海水样品时铀、钍、镭同位素和有 机碳的质量平衡状况，结果表明，１０ ＫＤａ中空纤维超滤膜对４０ ＫＤａ葡聚糖具有良 好的截留效率（８５％），而吸附损失率为 １８％．铀、钍、镭同位素和有机碳在超滤过程 中均达到极佳的质量平衡，回收率 Ｒ＝ ９５％～ ９８％，优于大多数文献报道的值． ２３４Ｔｈ在超滤过程中的渗透行为可以很好地用渗透模型加以描述．研究组分胶体态含量占“溶解”态含量的份额大小顺序如下：钍同位素、有机碳、镭同位素约等于铀同 位素，这与社为强颗粒活性元素、铀和镭为水溶性元素的地球化学性质相吻合．A cross-flow ultrafiltration system, including a prefilter (0. 22 μm), a Masterflex pump and a polysulfone hollow fiber 10 KDa ultrafiltration membrane (Amicon H10P10-20), is evaluated for its feasibility in sampling colloidal uranium, thorium, radium isotopes and organic carbon (OC) in seawater. The retention characteristics and sorptive potential of the ic KDa ultrafilter are examined through laboratory experiments using a 4o KDa fluoresceintagged dextran and standard 234Th as tracers. The mass balance of 234U, 238U, 234Th, 224Ra, 226Ra and OC during ultrafiltration is also evaluated. The results show that the 10 KDa ultrafiltration membrane can indeed tetain the 40 KDa dextran with a retention coefficient of 0. 85. However, sorptive loss of the 40 KDa dextran to the system is 18%. Mass balance of uranium, thorium, radium isotopes and OC are excellent, with recoveries ranging from 95 % to 98%, indicating that losses or contamination problems during ultrafiltration are minimal. The concentration of 234Th in the permeate, when plotted as a function of concentration factor, is found to fit an ultrafiltration permeation model. Percentage of colloids in the dissolved phase decreases as follows: thorium isotopes, organic carbon, radium isotopes abbot equaling uranium isotopes, which is consistent with their geochemical properties, i. e., thorium is a particle-reactive nuclide while uranium and radium are more soluble in seawater.

关 键 词：错流超滤技术 海洋胶体 铀 钍同位素 镭 有机碳 

分 类 号：P734.2[天文地球—海洋化学]