The quantitative effects of magnetic Fe3O4 nanoparticle content on Li+ adsorption and magnetic recovery performances of magnetic lithium-aluminum layered double hydroxides (MLDHs) were investigated systematically. MLDHs with different Fe3O4 nanoparticle contents were synthesized by a staged chemical coprecipitation method. The property disparities of these MLDHs were analyzed by various characterizations and results proved the existence of magnetic nanoparticles had no impairment on MLDHs crystal structure stability while the mesopores were lessened with the increasing Fe3O4 contents. In adsorption experiments using Qarhan Salt Lake brine with Mg/Li mass ratio of 284, the Li+ adsorption capacity of MLDHs presented a downtrend with the increasing Fe3O4, while the increased magnetic components had positive influence on the Li+ separation with Mg2+ on account of the steric effect. MLDHs presented excellent Li+ selectivity that the Mg/Li mass ratio of desorption solution was significantly decreased below 7.0. Relying on the superparamagnetism, MLDHs recovery all exceeded 97 % in the external magnetic field for only 10 min, and the magnetic recovery performance was promoted with more Fe3O4 nanoparticles. Furthermore, on the basis of experimental data, precise models were built and described well the correlations of Fe3O4 contents of MLDHs with Li+ adsorption capacity and magnetic recovery rate, respectively.

中文翻译：

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Fe3O4纳米颗粒含量对锂/铝磁性双层氢氧化物在超高Mg / Li比盐水中的Li +吸附和磁回收性能的定量影响。

系统研究了磁性纳米Fe3O4含量对磁性锂铝层状双氢氧化物（Li +）的Li +吸附和磁性恢复性能的定量影响。采用分段化学共沉淀法合成了不同Fe3O4纳米颗粒含量的MLDH。通过各种表征分析了这些MLDHs的性能差异，结果证明磁性纳米粒子的存在对MLDHs晶体结构稳定性没有损害，而随着Fe3O4含量的增加，中孔减少。在使用Mg / Li质量比为284的Qarhan盐湖盐水进行的吸附实验中，随着Fe3O4的增加，MLDHs的Li +吸附能力呈下降趋势，由于空间效应，增加的磁性成分对Li +与Mg2 +的分离具有积极影响。MLDHs具有出色的Li +选择性，解吸溶液的Mg / Li质量比显着降低到7.0以下。依靠超顺磁性，在外部磁场中，仅10分钟的MLDHs回收率均超过97％，并且更多的Fe3O4纳米颗粒可促进磁回收性能。此外，在实验数据的基础上，建立了精确的模型并很好地描述了MLDHs中Fe3O4含量与Li +吸附容量和磁回收率之间的关系。仅在10分钟内，MLDHs的回收率在外部磁场中均超过97％，并且更多的Fe3O4纳米颗粒可提高磁回收性能。此外，在实验数据的基础上，建立了精确的模型并很好地描述了MLDHs中Fe3O4含量与Li +吸附容量和磁回收率之间的关系。仅在10分钟内，MLDHs的回收率在外部磁场中均超过97％，并且更多的Fe3O4纳米颗粒可提高磁回收性能。此外，在实验数据的基础上，建立了精确的模型并很好地描述了MLDHs中Fe3O4含量与Li +吸附容量和磁回收率之间的关系。