Rapid separation of MOFs particles with the aid of PVDF hollow fiber membrane

Abstract

Metal-organic frameworks (MOFs) have been widely investigated due to their fascinating structures and properties. However, the time-cost synthetic process and the difficult separation from liquid phase hinder their practical application. In this study, a self-made automatic apparatus containing commercial poly(vinylidene fluoride) (PVDF) hollow fiber membranes was used to separate MOFs from large-volume suspension. Taking MIL-88A(Fe) synthesized with industrial-grade chemicals as an example, the investment cost, operation cost, human cost, time duration during separation process, and unit cost price of MIL-88A(Fe) were significantly reduced by 62%, 82%, 100%, 90%, and 36%, respectively, compared to those of centrifugation. More importantly, MIL-88A(Fe) powders that were separated and purified by the apparatus were easy to be removed from membrane surface by slight vibration, which displayed good morphology, crystallinity, as well as high degradation efficiency toward organic contaminants via photo-Fenton reaction. Meanwhile, the membrane can be reused instantly without any rinse. More encouragingly, this method is applicable to other MOFs’ separation, like ZIF-8 and ZIF-67. This study further confirmed the potential and prospective of high-throughput production and facile separation of MOFs for practical applications.