聚乙烯亚胺改性磁性酵母复合材料去除铀(VI)的性能

Adsorption properties of polyethyleneimine modified magnetic yeast composites for uranium (VI)

  • 摘要: 为了高效便捷地处理放射性废水,制备了聚乙烯亚胺(PEI)改性磁性酵母(MY)复合生物材料(MY@SiO2-PEI),并将其用于铀(VI)的去除。采用SEM、FTIR、Zeta电位及XPS对材料进行表征,运用Visual MINTEQ模拟不同条件下U(VI)形态分布,通过研究不同溶液pH、温度、反应时间、离子强度,阴离子(CO32−、PO43−)及不同U(VI)初始质量浓度等方面,考察不同因素对MY@SiO2-PEI吸附U(VI)的性能影响,并对MY@SiO2-PEI的循环利用能力进行研究。结果表明,MY@SiO2-PEI对U(VI)的吸附表现出强pH依赖性,离子强度对吸附效果无显著干扰,说明反应主要受表面络合作用控制。FTIR、XPS及Zeta电位分析发现促使U(VI)吸附的主要因素是材料表面不同官能团(N=C、NH(NH2)、C—N=C)与U(VI)的络合作用及静电吸引作用。MY@SiO2-PEI最大吸附量可达173.99 mg/g,且吸附在20 min就可达到吸附平衡。准二级动力学和Langmuir等温方程能很好的拟合此吸附过程,且热力学表明吸附过程是自发吸热过程。MY@SiO2-PEI材料的合成方法简便,去除效果好,再生性佳,是一种很有前途的环境污染治理中放射性核素的吸附剂。

     

    Abstract: In order to efficiently and conveniently treat radioactive wastewater, polyethyleneimine (PEI) modified magnetic yeast(MY) composite biological material(MY@SiO2-PEI) was prepared and used for the removal of uranium (VI).The material was characterized by SEM, FTIR, Zeta potential and XPS, the U(VI) morphology distribution under different conditions was simulated by Visual MINTEQ, the different solution pH, temperature, reaction time, ionic strength, anion interference(CO32−, PO43−) and different U(VI) in terms of initial mass solubility were analyzed. In addition, the influence of different factors on the adsorption performance of MY@SiO2-PEI on U(VI) was investigated, and the recycling capacity of MY@SiO2-PEI was studied. The results show that the adsorption of U(VI) by MY@SiO2-PEI shows a strong pH dependence, and the ionic strength does not significantly interfere with the adsorption effect, indicating that the reaction is mainly controlled by surface complexation. FTIR, XPS and Zeta potential analysis found that the main factor that promotes the adsorption of U(VI) is the complexation and electrostatic attraction of different functional groups (N=C, NH(NH2), C—N=C) and U(VI) on the surface of the material. The maximum adsorption capacity of MY@SiO2-PEI can reach 173.99 mg/g, and the adsorption equilibrium can be reached within 20 minutes. Quasi-second-order kinetics and Langmuir isotherm equation can fit this adsorption process well, and thermodynamics show that the adsorption process is a spontaneous endothermic process. MY@SiO2-PEI material has simple synthesis method, good removal effect and good reproducibility. It is a promising adsorbent for radionuclides in environmental pollution control.

     

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