改性沸石去除中低放废水中痕量放射性核素的研究

Removal of trace-amount radionuclide from low and medium level radioactive wastewaters by modified zeolite

研究了天然沸石的改性及其去除模拟中低放废水中痕量放射性核素的性能。将预处理好的天然沸石在浓度为0.25 mol/L的NaCl溶液中浸泡并在25℃、转速为200 r/min下恒温振荡24 h,洗净烘干后得到钠型改性沸石。研究了吸附时间、溶液pH、沸石投加量和竞争离子对沸石吸附Co2+的影响,得到了最佳吸附条件:Co2+起始质量浓度为400μg/L,25℃,pH=7,恒温振荡的平衡时间是8 h,固液比为1:800。竞争离子的存在对吸附效果的影响不大。吸附规律符合Langmuir和Freundlich等温式。

The modification of natural zeolite and its capacity for the removal of trace-amount radionuclide from low and medium level radioactive liquid has been studied.Pretreated natural zeolite is soaked in 0.25 mol/L NaCl solution and when the rotary speed is 200 r/min,it is shaked in constant temperature oscillator for 24 h at 25 ℃.After being washed and dried,the sodium-type modified zeolite is obtained.The effects of adsorption time,pH of the solution,dosage of zeolites and the existence of competing on the removal of Co ^2＋ process are examined.It is found that the optimal adsorption conditions are as follows： the initial Co ^2 ＋ mass concentration is 400 μg/L,pH =7,25 ℃,the equilibrium time of constant temperature oscillation 8 h,and solid-to-liquid ratio 1∶ 800.The existence of competing ions does not affect the removal efficiency too much.Adsorption rule is in accordance with Langmuir and Freundlich isotherms.