Hydrogen-Bonded Organic Frameworks@Bacterial Cellulose Mixed-Matrix Membranes for Pollution Elimination

Hydrogen-bonded organic frameworks (HOFs) represent promising porous photocatalytic candidates for water remediation, yet their practical deployment is severely hindered by their powdery nature, poor machinability, and limited recyclability. Herein, we report a facile in situ growth strategy to immobilize methyl-modified (HOF-101-CH3), fluorine-modified (HOF-101-F), and pristine HOF-101 nanocrystals within the three-dimensional interconnected nanofibrous network of bacterial cellulose (BC), yielding HOFs@BC mixed-matrix membranes (MMMs). Robust interfacial hydrogen bonding and physical cross-linking are constructed between HOF crystallites and BC nanofibers, which effectively suppress HOF aggregation, improve mechanical tolerance, and grant the composite membrane favorable hydrophilicity for aqueous-phase operation. Benefiting from the electron-donating methyl substituent, HOF-101-CH3-m delivers a more negative surface zeta potential (–28.8 mV), elevated charge-carrier separation efficiency, and superior dye-selective performance. It achieved a high selectivity ratio of 49.5 (permeation flux: 174 L m–2 h–1 bar–1) toward mixed cationic methylene blue (MB) and anionic methyl orange (MO), with 99.1% MB removal and merely 2% MO adsorption. After five separation-regeneration cycles, the membrane retains a selectivity ratio above 41.5 and maintains approximately 84% of its initial selectivity performance. Under visible-light irradiation, abundant reactive oxygen species (1O2, ·OH, and H2O2) are generated by the embedded HOF-101-CH3, endowing the membrane with photocatalytic self-cleaning capability. Notably, HOF-101-CH3-m achieves complete photodegradation of bisphenol A (BPA) within 50 min and maintains 95.3% degradation efficiency over five cyclic photocatalytic runs. This work demonstrates a feasible structural-engineering route to transform intractable powdery HOFs into mechanically robust multifunctional membranes, offering insights into the future design of HOF-derived functional materials toward integrated selective dye separation and photocatalytic elimination of organic water pollutants.