The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University , Beijing 100084, P. R. China.
Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
Langmuir. 2018 Feb 27;34(8):2674-2684. doi: 10.1021/acs.langmuir.7b04010. Epub 2018 Feb 12.
Separation of Sm from a dilute solution via conventional solvent extraction is often plagued by emulsion and third phase formation. These problems can be overcome with functionalized magnetic nanoparticles that can capture the target species and be separated from the raffinae phase rapidly and efficiently on application of a magnetic field. Magentic silica nanoparticles (FeO/SiO) were synthesized by a modified Stöber method and functionalized with carboxylate (FeO/SiO/RCOONa) and phosphonate (FeO/SiO/RRPONa) groups to achieve high adsorption capacity and fast adsorption kinetics. The adsorbents were characterized by X-ray diffraction analysis, transmission electron microscopy, BET measurements, magnetization property evaluation, Fourier infrared spectroscopy, and thermogravimetric analysis. Equilibrium adsorption of Sm on FeO/SiO/RCOONa particles was attained within 10 min and within 20 min on FeO/SiO/RRPONa nanoparticles. The kinetic data were correlated well with a pseudo-second-order model. Adsorption capacities of FeO/SiO/RCOONa and FeO/SiO/RRPONa were 228 and 180 mg/g, respectively. The recovery of the adsorbed Sm using 2 mol/L HCl as desorption agent was evaluated. The adsorption mechanism is discussed based on FTIR analysis, carboxylate group/Sm molar ratio, phosphonate group/Sm molar ratio, and pH. The adsorbents show significant potential for Sm recovery in industrial applications.
通过传统溶剂萃取从稀溶液中分离 Sm 通常会受到乳状液和第三相形成的困扰。这些问题可以通过功能化磁性纳米粒子来克服，这些纳米粒子可以捕获目标物种，并在施加磁场时迅速有效地从 raffinae 相中分离出来。通过改进的 Stöber 法合成了磁性二氧化硅纳米粒子（FeO/SiO），并用羧酸盐（FeO/SiO/RCOONa）和膦酸盐（FeO/SiO/RRPONa）官能化，以实现高吸附容量和快速吸附动力学。通过 X 射线衍射分析、透射电子显微镜、BET 测量、磁化特性评估、傅里叶变换红外光谱和热重分析对吸附剂进行了表征。在 10 分钟内达到了 FeO/SiO/RCOONa 颗粒上 Sm 的平衡吸附，在 20 分钟内达到了 FeO/SiO/RRPONa 纳米粒子上 Sm 的平衡吸附。动力学数据与拟二级模型很好地相关。FeO/SiO/RCOONa 和 FeO/SiO/RRPONa 的吸附容量分别为 228 和 180 mg/g。评估了使用 2 mol/L HCl 作为解吸剂回收吸附 Sm 的情况。根据 FTIR 分析、羧酸盐/Sm 摩尔比、膦酸盐/Sm 摩尔比和 pH 值讨论了吸附机理。这些吸附剂在工业应用中具有显著的回收 Sm 的潜力。
