某铀尾矿库区周围稻田土壤不同组分对U(Ⅵ)的吸附性能分析

通过斯笃克定律提取土壤胶体,连续提取法吸附土壤中的有机质,得到土壤矿质胶体,采用比表面积(BET)法和Zeta电位对原土、土壤胶体和矿质胶体进行了表征分析,考察了溶液pH、接触时间、U(Ⅵ)初始浓度以及温度等因素对3种样品吸附溶液中U(Ⅵ)的影响性能。结果表明:原土、土壤胶体和矿质胶体的比表面积和平均孔径分别为11.5,31.1,28.8 m2/g和18.76,35.55,17.5 nm。在pH为5.5,固液比在1.0 g/L,温度为20 ℃,U(Ⅵ)初始浓度为10.0 mg/L,土壤、土壤胶体反应时间为50 min,矿质胶体反应时间为40 min时,原土、土壤胶体、矿质胶体的对U(Ⅵ)吸附率分别达到76.67%、83.03%、48.87%,吸附容量分别达到8.53,9.24,5.43 mg/g。对比研究结果可以看出,土壤中的胶体对溶液中U(Ⅵ)有着明显的吸附能力,该研究结果对进一步研究含U(Ⅵ)废水的处理及U(Ⅵ)在土壤和地下水中的迁移过程有一定的参考意义。

ANALYSIS ON ADSORPTION PROPERTIES OF U(Ⅵ) BY DIFFERENT SOIL COMPONENTS IN PADDY SOIL AROUND A URANIUM TAILINGS POND

The soil colloid was extracted by Stoke’s law and the organic matter in the soil was removed by continuous extraction method to obtain mineral colloid. The original soil, soil colloid and mineral colloid were characterized by specific surface area (BET) method and Zeta potential determination. The effects of solution pH, reaction time, initial concentration of U(Ⅵ) and temperature on adsorption of U(Ⅵ) by the three samples were investigated. The results showed that the specific surface area and average pore diameter of the original soil, soil colloid and mineral colloid were 11.5, 31.1, 28.8 m2/g and 18.76, 35.55, 17.5 nm, respectively. When pH was 5.5, the solid-liquid ratio was 1.0 g/L, the temperature was 20 ℃, the initial concentration of U(Ⅵ) was 10.0 mg/L, the reaction time of soil and soil colloid was 50 min and the reaction time of mineral colloid was 40 min, the removal rates of original soil, soil colloid and mineral colloid reached 76.67%, 83.03% and 48.87%, respectively, and the adsorption capacities reached 8.53, 9.24, 5.43 mg/g, respectively. The colloid in soil had obvious adsorption ability on U(Ⅵ) in solution. It had certain reference significance for studying on the treatment of containing U(Ⅵ) wastewater and the migration process of U(Ⅵ) in soil and groundwater.