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针对含铀废液这类具有放射性的特殊废液,本实验选用养护28 d、粒径为200-220μm的水泥颗粒作为吸附剂,通过改变吸附时间t以及pH值,获得地质特种水泥对含铀溶液的静态吸附规律。实验结果表明,地质特种水泥对不同浓度含铀溶液(20 mg·L~(-1)、30 mg·L~(-1)、40 mg·L~(-1))的静态吸附均在第1.5 d基本达到吸附平衡,最大吸附量(q_e)分别达到40.257 mg·g~(-1)、60.423 mg·g~(-1)、80.386 mg·g~(-1),最终静态平衡吸附率高达99.95%;保持铀溶液浓度一定(30 mg·L~(-1)),改变吸附体系的pH值(5、7、9),地质特种水泥对U(Ⅵ)的吸附率均可达到99.50%,无显著差异。以上结果表明,在本实验设定的环境条件下,地质特种水泥对U(Ⅵ)有极强的吸附能力,且其吸附效果基本不受含铀溶液浓度和pH值的影响。同时,静态吸附动力学模型研究表明,伪二级动力学模型能很好地描述地质特种水泥静态吸附铀的全过程(t=0-41 d),其相关系数R~2高达99.99%,表明地质特种水泥对U(Ⅵ)的吸附机理为:吸附速率按照与吸附驱动力(q_e-q_t)的平方呈正比关系进行演变。
Aiming at the special radioactive wastewater containing uranium waste liquid, cement particles whose particle size is 200-220μm and whose curing time is 28 d were chosen as adsorption agent. By changing the adsorption time t and pH value, Static adsorption of the law. The experimental results show that the static adsorption of geotechnical special cement on uranium solution with different concentrations (20 mg · L -1, 30 mg · L -1, 40 mg · L -1) The maximum adsorption capacity (q_e) reached 40.257 mg · g -1, 60.423 mg · g -1 and 80.386 mg · g -1, respectively. The final static equilibrium adsorption rate Up to 99.95%. The concentration of uranium solution was kept constant (30 mg · L -1), the adsorption system pH value (5, 7, 9) was changed, and the adsorption rate of geological special cement to U (Ⅵ) %, No significant difference. The above results show that under the environmental conditions set in this experiment, the geotechnical special cement has a very strong adsorption capacity for U (Ⅵ), and its adsorption effect is basically unaffected by the uranium solution concentration and pH value. At the same time, the static adsorption kinetics model shows that the pseudo-second-order kinetic model can well describe the whole process of static adsorption of uranium on geological special cement (t = 0-41 d) with a correlation coefficient of R ~ 2 up to 99.99% The adsorption mechanism of U (Ⅵ) by geologic special cement is that the adsorption rate evolves in proportion to the square of adsorption driving force (q_e-q_t).