^(110)Ag^m在大亚湾表层沉积物上的吸附和解吸  

^(110)Ag^m Sorption and Desorption on Daya Bay Surface Sediment

作　　者：牟德海[1] 宋海青[2] 闫世平[1] 舒永红[1] 辜英杰[1] 蔡大川[1] 

机构地区：[1]中国广州分析测试中心广东省化学危害应急检测技术重点实验室,广东广州510070 [2]广东省环境辐射研究监测中心,广东广州510300

出　　处：《核化学与放射化学》2005年第3期158-163,共6页Journal of Nuclear and Radiochemistry

基　　金：广东省自然科学基金资助项目(20000088)

摘　　要：为了解放射性核素110Agm在大亚湾水域中的迁移和运输,采用批次法研究了4个大亚湾表层沉积物在天然海水中对110Agm的吸附和解吸行为。在吸附反应体系中,Ag+的质量浓度为1.3 ng/mL,110Agm的放射性浓度为10.0 Bq/mL,海水的pH为8.20,盐度为32.0,固液比为1.0 mg/mL时,在短时间(约40 s)内,110Agm的吸附率即达到28.6%。说明大亚湾表层沉积物对110Agm存在一个快速吸附过程;在吸附时间1 h以内吸附率变化很小,4个沉积物的平均吸附率为30.0%;从1 h^5 d,吸附率可上升至64.4%;5 d以后吸附趋于平衡,吸附分配比平均为1.86×103mL/g,与解吸实验达到平衡时的吸附分配比1.90×103mL/g相同。在固液比为4~250 mg/L时,110Agm的吸附分配比随固液比的增加而减小,在250~1 000 mg/L内,随固液比的增加而增加,当固液比大于1 000 mg/L时,分配比基本上保持一个恒定值。In order to comprehend the transportation and movement of radioactive ^110Ag^m in water area of Daya Bay, the sorption/desorption of radioactive ^110Ag^m on four surface sediment samples collected from Daya Bay are investigated by batch method in sea water at ambient temperature. The experimental conditions are as follows： the concentration of silver ions, ρ（Ag^＋ ）=1.3 ng/mL; the radioactivity concentration of ^110Ag^m , c（^110Ag^m）=10.0 Bq/mL,pH=8.20 and salinity 32.0 for sea water; ratio of sediment to sea water, n=1. 0 mg/mL. The observed percentage of sorption （Rad） of ^110Ag^m reached 28.6% by about 40 seconds which is the most shortest time could be obtained in the present sorption experiment, which suggest the initial sorption step is much quickly. Within 1 hour of contact time, Rsd is 30.0 % averagely for four sediment samples and varied slightly. From 1 hour to 5 days of contact time, Rad increase slowly from 30.0%to 64.4%. From 5 days to the end of experiment （113 d）, no remarkable change of Rad is observed, suggesting that the sorption process approach a steady state after 5 d of contact time. The distribution ratio （D） at steady state is around 1.86 × 10^3 mL/g for sorption experiment, which is almost the same as that of 1.90× 10^3 mL/g for desorprtion experiment under the same experimental conditions. The effects of ratio of sediment to sea water （n） on D are clearly observed in the present paper. The values of D decrease with increase of n in the range of 4-250 mg/mL, increased with increase of n in the range of 250-1 000 mg/mL, and var small when n is greater than 1 000 mg/mL.

关 键 词：^110Ag^m 大亚湾 表层沉积物 吸附 解吸 固液比 

分 类 号：O647.3[理学—物理化学]