Metal-organic frameworks decorated wood aerogels for efficient particulate matter removal

The severe indoor/outdoor air contamination caused by hazardous particulate matters (PMs) has a devastating impact on the environment and human health. Herein, air filters fabricated from delignified wood aerogels and metal-organic frameworks (MOFs) were used for PM removal. Two specially designed MOFs (i.e. Zn-based ZIF-L and Zr-based UiO-66-NH₂) were deposited into a highly porous wood matrix through in situ growth approach. The MOF crystals are attached tightly to the highly available cellulose surface groups and distributed uniformly. The integration of MOFs can regulate the aerogel morphology and surface property, leading to enhanced PM removal performance. Bare wood aerogels beard removal efficiencies of 70.7% and 75.0% for PM_2.5 and PM₁₀, with a low-pressure drop of 15 Pa. By contrast, ZIF-L decorated wood aerogels exhibited PM_2.5 and PM₁₀ removal efficiencies of 97.6% and 99.5%, respectively, which are ascribed to the increased interception/impaction of PMs with the positively charged ZIF-L layer. While UiO-66-NH₂ functionalized wood aerogels demonstrated PM_2.5 and PM₁₀ removal efficiencies of 96.4% and 98.9% because of the hierarchical filter matrix and the presence of polar -NH₂ groups. Moreover, MOF modified wood aerogels can be easily regenerated and superior reusability can be achieved. This work provides an effective and economic strategy for the preparation of air filters from renewable materials.