粘土岩对铀(Ⅵ)的吸附性能

Adsorption mechanism of uranium(Ⅵ) by clay rock

以内蒙古阿拉善粘土岩为原料,采用静态吸附的方法,研究了不同因素对吸附铀(Ⅵ)效果的影响,通过吸附量和吸附率对结果进行分析.结果表明,粘土岩对铀(Ⅵ)的吸附效果较好,10 h就达到了平衡;在铀(Ⅵ)的最佳初始浓度为40μg·mL-1时,吸附率达到最大;不同离子的影响不同,阳离子中,Mg2+的影响最大,Na+和K+几乎没影响,阴离子中,CO32-和HCO-3的影响最大,其次是SO42-,而NO-3基本没有影响;最佳固液比为1∶40;吸附率和吸附量都随腐殖酸浓度的升高而减小;pH对吸附的影响较大,最佳pH值为6;吸附率和吸附量都随温度的升高而增大.Freundlich等温吸附模型较Langmuir能更好的拟合吸附过程.

Using the Alashan clay rock in Inner Mongolia as the raw material,the static adsorption method was used to study the influence of different factors on the adsorption of uranium(Ⅵ),and the results were analyzed by adsorption amount and adsorption rate.The results indicated that the clay rock adsorbed uranium(Ⅵ)well,and the equilibrium reached within 10 h.The optimum initial concentration of uranium(Ⅵ)was 40μg·mL-1,and the adsorption rate reached the maximum.Different ions had different effects.Among the cations,Mg2+had the greatest influence,Na+and K+had almost no effect.Among the anions,CO32-and HCO-3 had the greatest influence,followed by SO42-,and NO-3 had little effect.The optimum solid-liquid ratio was 1∶40.Both adsorption rate and adsorption amount decreased with the increase of the concentration of humic acid.pH had a greater influence on the adsorption,and the optimal pH was 6.The adsorption rate and the adsorption amount increased with the increase of temperature.The Freundlich isotherm adsorption model fit the adsorption process better than Langmuir.