Recently, Dr. Jiang Gengping, a young teacher from the Department of Applied Physics of the Faculty of Science, published a paper Efficient metal ion sieving in rectifying subnanochannels enabled by metal–organic frameworks as the corresponding author in Nature Materials (Nature Materials, 2020, 1476-4660) . The research result is the result of the collaboration between Dr. Jiang Gengping and the team of Professor Wang Huanting of Monash University in Australia to jointly study the problems of ion transport and screening in the metal organic framework (MOF).
Since 1999, Professor Yaghi of the University of California, Berkeley successfully synthesized the world's first MOF material. So far, more than 18,000 MOF materials with different structures and properties have been designed and successfully prepared in the past two decades.MOF has very unique application prospects in the fields of energy storage, electrochemical reactions, sensors, gas adsorption/separation, biomedicine, etc. due to its high specific surface area, unique pore structure, various adjustable functional groups and large-scale production characteristics.
With the development of MOF materials, its application background has gradually developed from the early dry gas or non-aqueous solutions (such as ionic liquids or organic solvents) to aqueous solutions, and even the emergence of stable existence in strong acid or alkali environments The emerging MOF material has laid a solid foundation for extending its application background to aqueous systems and biomedical fields. In this study, UiO-66-(COOH)2 crystals were filled into pre-prepared PolyEthylene Terephthalate, PET micro/nano pores (d = 200~500 nm) to form a stable sub-surface inside the MOF material. Nanopores (d<1 nm). The transmission results of monovalent and divalent cations show that UiO-66-(COOH)2 can achieve a separation ratio of up to two to four orders of magnitude for monovalent and divalent ions at different concentrations and pH values.
In this regard, Dr. Jiang Gengping used molecular dynamics simulation to reveal its internal ion transmission process, and also proved that as the strength of the ion hydration shell increases, the ion mobility inside the MOF also decreases.
The simulation results of the mean potential (PMF) show that the process of ions passing through the MOF window is accompanied by a complex process of detachment and recombination of peripheral water molecules, as well as configuration changes of the organic framework and functional groups along with the migration of ion positions. This complex process creates different energy barriers for different ions in the transmission process, that is, different ion mobilities in experiments and simulations. In this study, Monash University in Australia is the main completion unit. The first author is doctoral student Lu Jun, the co-first author and corresponding author are Dr. Zhang Huacheng of Monash University, and the remaining corresponding authors are Professor Wang Huanting and Monash University respectively. Dr. Jiang Gengping, University of Wuhan University of Science and Technology.
