纤维状磁性二氧化钛复合材料的制备及其对La3+的吸附行为

Preparation of fibrous magnetic titania composites and their adsorption behavior for La3+

  • 摘要: 为富集回收低浓度矿山尾水中稀土资源,采用溶胶-凝胶法和水热法制备了纤维状外壳的磁性二氧化钛复合材料Fe3O4@fTiO2,利用SEM、TEM、XPS、FTIR和XRD对材料进行表征,考察了Fe3O4@fTiO2对稀土La3+的吸附行为。结果表明:Fe3O4@fTiO2是外壳为纤维状的核壳结构磁性复合材料;吸附剂具有良好的超顺磁性,饱和磁化强度高达30.81 emu·g−1;在15℃、pH=5的酸性条件下,Fe3O4@fTiO2对稀土La3+在15 min内达到吸附平衡,且符合伪一级动力学模型;Langmuir等温吸附模型能较好地描述吸附La3+过程,理论吸附容量为142.88 mg·g−1;Fe3O4@fTiO2在NaOH的再生下循环利用5次时的吸附量为110 mg·g−1,是首次吸附容量的73.8%,表现出良好的循环利用性。

     

    Abstract: In order to enrich and recover rare earth resources in low-concentration mine tail water, a fibrous shell magnetic titanium dioxide composite Fe3O4@fTiO2 was prepared by using sol-gel method and hydrothermal methods. The material was analyzed by SEM, TEM, XPS, FTIR and XRD. The adsorption behavior of Fe3O4@fTiO2 for rare earth La3+ was investigated. The results show that Fe3O4@fTiO2 is a core-shell magnetic composite with a fibrous shell. The adsorbent has good superparamagnetic properties, and the saturation magnetization is as high as 30.81 emu·g−1. At pH=5 and 15℃, Fe3O4@fTiO2 reaches the adsorption equilibrium for rare earth La3+ within 15 min, and conformes to the pseudo-first-order kinetic model. The Langmuir isotherm adsorption model can describe the adsorption process of La3+ well, with the theoretical adsorption capacity of 142.88 mg·g−1. With NaOH solution as the regeneration reagent, the adsorption capacity of Fe3O4@fTiO2 is 110 mg·g−1 after cyclic adsorption/desorption for 5 times, which is 73.8% of the initial value, showing the good cyclic utilization.

     

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