石榴皮炭负载CaTiO3复合材料去除溶液中U(VI)的性能与机制

Performance and mechanism of U(VI) removal from solution by pomegranate peel carbon supported CaTiO3 composites

  • 摘要: 当今社会能源短缺,核能发展迅速,为了实现绿色高效的能源利用目标,如何处理核能发展过程产生的含铀废物已成为日益突出的环境问题。本文首先采用溶剂热法制备CaTiO3材料,然后通过与石榴皮炭材料混合研磨合成炭材料负载CaTiO3 (C@CaTiO3),采用现代表征技术分析C@CaTiO3与U(VI)反应前后形貌及物质组成变化。通过静态实验法研究了材料去除溶液中铀的性能。研究结果表明:在pH=3.5、U(VI)初始浓度为25 mg·L−1、反应时间40 min、温度为25℃的条件下,材料对U(VI)的去除率为96.26%,去除量为119.21 mg·g−1。通过吸附动力学模型、等温吸附模型和热力学模型,探究了C@CaTiO3与U(VI)的反应机制。结果表明:C@CaTiO3对U(VI)的吸附过程是自发进行的吸热反应,C@CaTiO3对溶液中U(VI)的去除存在吸附和还原两种方式,吸附为物理吸附和化学吸附并存、以表面单层化学吸附为主。还原以光催化还原作用为主。

     

    Abstract: In order to achieve the goal of green and efficient energy utilization, how to deal with uranium-containing waste generated during the development of nuclear energy has become an increasingly prominent environmental problem. The CaTiO3 materials were initially prepared using the solvent-thermal method. Subsequently, the carbon material was synthesized by grinding a mixture of CaTiO3 and pomegranate peel carbon material, resulting in the formation of carbon-loaded CaTiO3 (C@CaTiO3). Modern characterization techniques were employed to analyze the morphological and compositional changes of C@CaTiO3 before and after its reaction with U(VI). The performance of the material in removing uranium from the solution was evaluated using a static experimental method. The research findings revealed that, under the conditions of pH=3.5, an initial concentration of U(VI) of 25 mg·L−1, reaction time of 40 min, and temperature of 25℃, the material exhibited a U(VI) removal rate of 96.26% with a corresponding removal capacity of 119.21 mg·g−1. The reaction mechanism between C@CaTiO3 and U(VI) was investigated using adsorption kinetics models, isothermal adsorption models, and thermodynamic models. The results demonstrate that the adsorption process of U(VI) by C@CaTiO3 is a spontaneous endothermic reaction. The removal of U(VI) from the solution using C@CaTiO3 involved both adsorption and reduction, with physical and chemical adsorption coexisting and surface monolayer chemical adsorption being the predominant mechanism. Photocatalytic reduction played a major role in the reduction process.

     

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