Incorporating polyvinylpyrrolidone modified HOF-101 into Pebax membranes for efficient toluene/N2 separation

Abstract

Hybrid membranes hold great promise in the recovery of volatile organic compounds (VOCs). Hydrogen-bonded organic framework (HOF), a class of hydrogen-bonded crystalline porous materials with high affinity toward VOCs, holds great potential as an emerging filler. In this study, highly stable HOF-101 modified by Polyvinylpyrrolidone (PVP) and introduced into polyether block amide (Pebax®1657) to prepare hybrid membrane. The π-conjugated large aromatic ring structure of HOF-101 promoted the adsorption of toluene molecules. The interaction between the Pebax polymer chain segments and PVP on the modified HOF-101 surface enhanced their interfacial compatibility. At a PVP@HOF-101 content of 1 ​wt%, the hybrid membrane exhibited optimal separation performance for a 2.2 ​mol% toluene/N₂ mixture, with a permeability of 1.51 ​× ​10⁻⁶ ​mol ​μm ​m⁻² s⁻¹ ​Pa⁻¹ for toluene, a selectivity of 954 and excellent stability over 120 ​h in the long-term experiment. This study demonstrates the application of HOF-based hybrid membranes for VOCs recovery.