Enhancing MOF Binding and Distribution via Plant Fiber Branch-Networking Strategy for Efficient Formaldehyde Adsorption and Dust Filtration

Renewable cellulose fibers can be mechanically disintegrated into micro-/nanoscale fibrils with tunable dimensions, offering a sustainable and processable scaffold for constructing high-performance functional media. However, paper-based filtration/adsorption materials integrated with metal–organic frameworks (MOFs) often suffer from porous-structure instability under airflow, weak interfacial anchoring, and heterogeneous MOF distribution, which together cause pressure-drop fluctuation, limited active-site utilization, and potential particle shedding. Herein, inspired by Da Vinci’s branching rule, we propose a branching-to-network design strategy enabled by moderate pulp refining to reconstruct cellulose fibers into a multiscale, hierarchically connected scaffold. Refining-induced microfibrillation transforms bundled fibers into a branched network with increased junction density and continuous load-transfer pathways, thereby stabilizing the porous architecture against airflow-induced deformation. Concurrently, microfibrillation exposes abundant hydroxyl-rich surfaces that strengthen interfacial anchoring with Co²⁺/MOF precursors and provide dense nucleation sites, enabling uniform in situ growth and robust immobilization of ZIF-67 throughout the fibrous network. Benefiting from the synergistic integration of a branching cellulose scaffold and uniformly distributed MOF functional nodes, the resulting ZIF-67@MFC composite paper achieves efficient formaldehyde capture (0.18   mg   g⁻¹) and high fine-particulate removal efficiency (99%). Moreover, the biodegradable cellulose matrix, coupled with MOF-enabled structural disintegration, facilitates rapid degradation of the composite within 30 days in soil. Importantly, the entire fabrication route is fully compatible with conventional wet-end papermaking and can be readily scaled up using industrial equipment, providing a low-cost and sustainable platform for next-generation air-purification and personal-protective filtration materials. Download: Download high-res image (116KB) Download: Download full-size image