偕胺肟基聚偏氟乙烯粉体对铀酰离子的吸附研究

Adsorption of the uranyl Ions on an amidoxime-based polyvinylidene fluoride powder

通过批量吸附实验研究了辐射接枝技术制备的偕胺肟基聚偏氟乙烯(PVDF-g-PAO)粉体对低浓度铀酰离子的吸附行为,考察铀酰离子初始浓度、温度、pH值对吸附行为的影响。结果表明,PVDF-g-PAO粉体对低浓度铀酰离子的吸附较快,约180 min达动态平衡,吸附过程符合准二级动力学模型和Freundlich等温吸附模型,吸附反应是熵增加的吸热反应。体系pH值对铀酰离子吸附率影响表明,pH值在5?8范围内时,吸附率变化不大,偕胺肟基材料比较适合海水环境下的吸附,同时发现对材料上已吸附铀酰离子可用酸或碱溶液脱附。

The adsorption behavior of uranyl ions in low initial concentration on the amidoxime group functionalized polyvinylidene fluoride powder polymeric material （PVDF-g-PAO） was investigated by batch sorption experiments in this paper, while influences of initial uranyl ions concentration, temperature and the pH value were also concerned. The adsorption equilibrium time can be reached after about 180 min. Adsorption kinetic pattern is in good agreement with the pseudo-second-order model, and the Freundlich isotherm model fits the adsorption equilibrium data well. The uranyl ions adsorption on PVDF-g-PAO is pH dependent, where the adsorption rate keeps constant with the pH value ranging from 5 to 8 （being acclimatized to seawater pH value）, but decreases obviously in the acid and alkali system. It is obvious that acid and alkali solutions are effective eluting agents for uranyl ions adsorbed on PVDF-g-PAO powder.