中国科学院化学研究所田野团队报道了用于稀土元素的选择性运输的取向受控的大规模有机框架纳米单层。相关研究成果发表在2023年5月25日出版的《美国化学会杂志》。

长期以来，由多孔纳米颗粒组成的长程有序膜一直被用于精确分离。然而，大多数制造方法都受到基板有限或缺乏对晶体取向的精确控制的影响。

该文通过超亲光基质限制的界面自组装过程制备了具有可控取向的大规模金属-有机框架（MOF）单层膜。反应物微滴的超扩散导致在不混溶的油下形成超薄液体层作为受限反应器。伴随的MOF（ZIF-8）颗粒自发组装成具有受控取向的单层，该取向由颗粒在液体/液体界面的接触角决定，该接触角可由溶剂组成调节。其中气体吸附和离子传输测试都证明了111取向膜表现出最小的传质阻力。所制备的膜可以选择性地传输稀土元素，La³⁺/K⁺的选择性达到14.3。分子动力学模拟表明，稀土元素的选择性与离子-膜结合能的显著差异有关，这证明了ZIF-8膜在从工业废物中高效回收稀土元素方面的潜力。

附：英文原文

Title: Large-Scale Metal–Organic Framework Nanoparticle Monolayers with Controlled Orientation for Selective Transport of Rare-Earth Elements

Author: Ming Qiu, Zhongpeng Zhu, Dianyu Wang, Zhe Xu, Weining Miao, Lei Jiang, Ye Tian

Issue&Volume: May 25, 2023

Abstract: Long-range ordered membranes comprised of porous nanoparticles have been pursued in precise separations for a long time. Yet most of the fabrication methods suffer from limited substrates or lack of precise control over crystal orientation. Herein, large-scale metal–organic framework (MOF) monolayer membranes with controlled orientations are prepared through an interfacial self-assembly process confined by superlyophilic substrates. The superspreading of reactant microdroplets results in an ultrathin liquid layer under an immiscible oil as a confined reactor. The concomitant MOF (ZIF-8) particles spontaneously assemble into monolayers with controlled orientations, determined by the particles’ contact angles at the liquid/liquid interface, which can be regulated by solvent compositions. Therein both gas-adsorption and ion-transport tests prove that the 111-oriented membrane exhibits a minimized mass-transfer resistance. The as-prepared membrane can selectively transport rare-earth elements (REEs), and a La3+/K+ selectivity of 14.3 is achieved. Molecular dynamics simulations reveal that the REEs-selectivity is associated with the distinct difference in ion–membrane binding energies, demonstrating the potential of ZIF-8 membranes for use in high-efficiency recovery of REEs from industrial wastes.

DOI: 10.1021/jacs.3c02716

Source: https://pubs.acs.org/doi/10.1021/jacs.3c02716