Adsorption and separation of rare earth ions by competitive coordination-induced hierarchical porous metal-organic frameworks
Wang Jia1, Cong Xin2, Feng Yuxiang2, Yang Jin2, Ma Mingshu3, Chen Li3
1. Jiangsu SOPO (Group) Corporation Ltd., Zhenjiang 212006， China; 2. Jiangsu Sopo Chemical Corporation Ltd., Zhenjiang 212006, China; 3. School of Chemistry and Chemical Engineering Jiangsu University, Zhenjiang 212013, China
Aiming at the efficient adsorption and separation of adjacent co-existed rare earth ions praseodymium (Pr), neodymium (Nd) and samarium (Sm), solvothermal method to construct a novel hierarchical MOF-5 adsorbent were applied using lauric acid as a competitive coordination agent. The chemical compositions, crystalline structure and hierarchical pore structures of the synthesized MOF-5 were demonstrated by infrared spectroscopy, nitrogen absorption and desorption curves, X-ray diffraction and scanning electron microscopy. By adjusting the solvothermal reaction time and lauric acid’s addition amount, the surface of the as-prepared hierarchical MOF-5 could be covered by a rod-like grain with average length of about 0.1μm, and the whole MOF-5 crystals were cubes with a side length of about 1μm, and the average pore size was around 16.46 nm. The equilibrium adsorption amounts of Pr, Nd and Sm were 84.82 mg/g, 153.88 mg/g and 228.34 mg/g, respectively. The separation coefficients of Sm/Nd and Nd/Pr calculated from the kinetics adsorption equilibrium data were 1.47 and 1.83, respectively.
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