磁性介孔TiO2/氧化石墨烯复合材料的制备及其对U(Ⅵ)的吸附

Preparation of magnetic mesoporous TiO2/graphene oxide composites and their adsorption for U(Ⅵ)

  • 摘要: 以氧化石墨烯(GO)、纳米Fe3O4、钛酸四丁酯(TBOT)为原料,合成了磁性介孔TiO2/GO(Fe3O4@TiO2/GO)复合材料,用其处理浓度为10 mg·L-1的含U(Ⅵ)废水。研究了Fe3O4@TiO2/GO复合材料中GO含量、溶液初始pH值、Fe3O4@TiO2/GO复合材料投加量、反应时间、U(Ⅵ)初始浓度及共存离子对U(Ⅵ)吸附的影响。结果表明:在pH值为6、GO质量分数为60wt%、Fe3O4@TiO2/GO复合材料投加量为10 mg的条件下,Fe3O4@TiO2/GO复合材料对U(Ⅵ)的吸附效果最佳,较同等条件下磁性介孔Fe3O4@TiO2复合材料和GO的吸附量分别高了10.99 mg·g-1和1.91 mg·g-1。Fe3O4@TiO2/GO复合材料对U(Ⅵ)的吸附180 min即达到平衡,准二级动力学模型和Freundlich吸附等温模型能很好地描述其吸附过程。解吸实验表明,经5次吸附-解吸后,U(Ⅵ)的吸附率仍高达90.86%,说明Fe3O4@TiO2/GO复合材料具有较高的循环利用性能。

     

    Abstract: The magnetic mesoporous TiO2/graphene oxide (Fe3O4@TiO2/GO) composites were prepared by the synthesis of graphene oxide (GO), nano Fe3O4 and tetrabutyl titanate (TBOT), then the Fe3O4@TiO2/GO composites were used to treat U(Ⅵ)-containing waste water at a concentration of 10 mg·L-1. The effects of mass fraction of GO in Fe3O4@TiO2/GO composites, initial pH of solution, the dosage of Fe3O4@TiO2/GO composites, reaction time, initial uranium concentration and coexisting ions on U(Ⅵ) adsorption on Fe3O4@TiO2/GO composites were investigated. The results show that the Fe3O4@TiO2/GO composites has the best adsorption for U(Ⅵ) when the pH value is 6, the mass fraction of GO is 60wt% and the Fe3O4@TiO2/GO composites dosage is 10 mg, under the same conditions, the adsorption capacity of U(Ⅵ) is 10.99 mg·g-1 and 1.91 mg·g-1 higher than that of Fe3O4@TiO2 composites and GO, respectively. The adsorption results of the Fe3O4@TiO2/GO composites are balanced at 180 min, and the pseudo-second-order kinetics model and the Freundlich adsorption isotherm model are good descriptions of the adsorption of the Fe3O4@TiO2/GO composites for U(Ⅵ) process. The results of desorption experiments show that the adsorption efficiency of the Fe3O4@TiO2/GO composites for U(Ⅵ) remains as high as 90.86% after 5 cycles of adsorption-desorption, indicating that the Fe3O4@TiO2/GO composites have higher recycling performance.

     

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