聚苯胺@碳纳米纤维复合材料对放射性核素铀的高效去除

本文通过原位聚合方法成功制备了聚苯胺改性的碳纳米纤维(PANI@CNF)复合材料,并用于水溶液中放射性核素铀(U(VI))的高效去除.扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、傅里叶红外光谱(FTIR)和X射线光电子能谱(XPS)等表征证明所制备的材料具有丰富的官能团和优良的物理化学性质.批实验方法系统研究了周围环境(pH、背景电解液、反应时间和温度)的变化对U(Ⅵ)去除结果的影响.结果表明,pH对于U(Ⅵ)去除影响很大,而离子强度没有影响,表明二者之间的作用机理为内层表面络合.吸附能够在30 min内快速达到平衡,且符合拟二级动力学模型.吸附等温线符合Langmuir等温线,表明U(Ⅵ)的去除是单分子层均匀吸附过程.在pH=5.0和T=298 K时, PANI@CNF对U(Ⅵ)的最大吸附量高达319.4 mg/g,远远高于单纯的CNF(133.9 mg/g). U(Ⅵ)主要与材料表面的含氮和含氧官能团形成了稳定的内层络合物,从而达到高效去除的目的.以上分析表明, PANI@CNF具有快速反应动力学和高效吸附能力,可以作为放射性核素高效去除的潜在储备材料,为我国核废料治理工作提供理论依据.

Highly efficient removal of radioactive uranium on polyaniline modified carbon nanofiber composites

In this article,polyaniline modified carbon nanofiber(PANI@CNF)composites were synthesized by.zw situ polymerization technique,and applied to highly efficient removal of radioactive uranium;(U(VI))-fiom s aqueous solutions.The prepared materials had abundant functional groups and excellent physical and chemical properties,which was confirmed by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray'diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).The adsorption of U(VI)from aqueous solutions as a function of pH,ionic strength,reaction time and temperature on the materials were investigated by batch experiments.The elimination of U(VI)was strongly dependent on pH but independent of ionic strength,indicating that the interaction was mainly dominant by inner-sphere surface complexation.The adsorption kinetics were well simulated by pseudo-second-order model and reached reaction equilibrium within 30 min.The adsorption isotherms were well described by Langmuir isotherm model,implying that the elimination of U(VI)was monolayer coverage.At pH=5.0 and 7^=298 K,the maximum adsorption capacity ofU(VI)on PANI@CNF(319.4 mg/g)was higher than those of U(VI)on CNF(133.9 mg/g),which was attributed to the synergistic effects'between oxygen functional groups and nitrogen functional groups.Such a facile preparation method and efficient removal performance highlighted the application of PANI@CNF as a candidate for rapid and efficient radionuclide contamination's elimination in practical applications.