Development of state-of-the-art selective adsorbent materials for recovery of rare earth elements (REEs) is essential for their sustainable usage. In this study, a metal-organic framework (MOF), MIL-101(Cr), was synthesized and post-synthetically modified with optimised loading of the organophosphorus compounds tributyl phosphate (TBP), bis(2-ethylhexyl) hydrogen phosphate (D2EHPA, HDEHP) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex®-272). The materials were characterized and their adsorption efficiency towards Nd³⁺, Gd³⁺ and Er³⁺ from aqueous solutions was investigated. The MOF derivatives demonstrated an increase in adsorption capacity for Er³⁺ at optimal pH 5.5 in the order of MIL-101-T50 (37.2 mg g⁻¹) < MIL-101-C50 (48.9 mg g⁻¹) < MIL-101-H50 (57.5 mg g⁻¹). The exceptional selectivity of the materials for Er³⁺ against transition metal ions was over 90%, and up to 95% in the mixtures with rare earth ions. MIL-101-C50 and MIL-101-H50 demonstrated better chemical stability than MIL-101-T50 over 3 adsorption−desorption cycles. The adsorption mechanism was described by the formation of coordinative complexes between the functional groups of modifiers and Er³⁺ ions.

开发用于回收稀土元素（REE）的最新选择性吸附材料对于其可持续利用至关重要。在这项研究中，合成了金属有机骨架（MOF）MIL-101（Cr），并通过优化负载有机磷化合物磷酸三丁酯（TBP），双（2-乙基己基）磷酸氢盐（D2EHPA）进行了合成后修饰，HDEHP）和双（2,4,4-三甲基戊基）次膦酸（-272）。对材料进行了表征，并研究了其对水溶液中Nd ³⁺，Gd ³⁺和Er ³⁺的吸附效率。在最适pH 5.5下，MOF衍生物对Er ^3+的吸附能力呈MIL-101-T50的顺序增加（37.2 mg g ^-1）<MIL-101-C50（48.9 mg g ^-1）<MIL-101-H50（57.5 mg g ^-1）。该材料对Er ³⁺对过渡金属离子的特殊选择性超过90％，在与稀土离子的混合物中高达95％。在3个吸附-解吸循环中，MIL-101-C50和MIL-101-H50的化学稳定性优于MIL-101-T50。通过在改性剂和Er ³⁺离子的官能团之间形成配位配合物来描述吸附机理。