Enhancing selectivity for erythromycin separation from water by Incorporating hydrophilic MOF-801 into the polyamide layer of Thin-Film nanocomposite membranes

Abstract

The construction of the polyamide functional layer in thin-film nanocomposite membranes(TFN) is pivotal for improving permeability and selectivity. A key scientific challenge in the field of nanofiltration is how to substantially enhance membrane separation efficiency through the incorporation of advanced filler materials. In this study, we utilized an interfacial polymerization (IP) process to embed the highly promising MOF-801, known for its potential in water collection in desert environments, into the TFN functional layer, targeting applications such as wastewater antibiotic filtration or erythromycin concentration. The results indicate that MOF-801 can be employed to fabricate a highly selective (erythromycin and NaCl rejection rates of 95 % and 20 %, respectively) and highly permeable (permeation constant of 14 L m⁻2 h⁻1 bar⁻1) functional layer on a PVDF substrate. The efficient separation mechanism is attributed to MOF-801′s capacity to fully exploit its intrinsic hydrophilicity and microporous features within the functional layer, thereby enhancing steric hindrance effect and Donnan exclusion effects, which may help overcome the “trade-off” limit. In terms of antifouling performance, the hydrophilicity of MOF-801 and the exposed Zr⁴⁺ sites confer a competitive advantage to the PA@MOF-801_0.1%PVDF in practical applications. This work broadens the application of hydrophilic MOFs in membrane modification and suggests that researchers explore more innovative functional layer design strategies.