铀在红壤实性成分上的吸附行为研究

Sorption of Uranium onto Solid Components of Red Earth

通过制备红壤实性成分样品,研究铀在红壤实性成分上的吸附行为,讨论固液比、p H、接触时间、离子强度、腐殖酸、温度等条件对铀在红壤样品上吸附行为的影响。结果表明,吸附在4 h可达平衡;在p H<8.5时,吸附率随p H的增大而增加;在p H>8.5时,吸附百分率则出现递减。在p H<6时,随腐殖酸浓度增加,红壤实性成分对铀的吸附增强;在p H>6时,HA存在下,吸附率反而减少。以Freundlich吸附模型对吸附过程进行了描述,并绘制了不同温度下的吸附等温线,计算了相应的热力学函数。由热力学函数计算结果可知吸附是吸热且自发的过程。

As a function of p H,contact time,ionic strength,temperature,humic acid,solid-liquid ratio（ m / V）and other external conditions,the sorption behaviors of uranium on solid components of red earth（ SCRE） are studied. The results show that the time to achieve sorption equilibrium is about 4h. At p H 8. 5,the sorption increases with p H increasing; while decreases with p H increasing at p H 8. 5. The presence of HA enhances the sorption at p H 6,and reduces the sorption at high p H values. Freundlich model are adopted to describe the sorption,and thermodynamic parameters（ ΔG0,ΔS0,and ΔH0） are calculated. The results indicated that the sorption of U（ Ⅵ） on SCRE is an endothermic and spontaneous process.