Bioinspired PM2.5 Filter: an AgNWs Reinforced PAN/PVP Composite Membrane with the Porous and Multilayered Network Structure

Particulate matter (PM) pollution poses a lethal threat to human health. Fortunately, nature has evolved efficient strategies to construct unique structures that exhibit high PM2.5 purification efficiency, one such example is found in the aloe leaf. Here, inspired by the surface structure of aloe vera leaves, a PAN/PVP nanofiber composite membrane with the porous and multilayered network structure (P-N) was designed and fabricated for efficient air filtration via electrospinning combined with hot-pressing technique. Furthermore, the dynamic purification process of PM2.5 in the P-N was racked and studied through a combination of experimental and computational fluid dynamics methods. The results demonstrated that the flow path of PM2.5 is extended and the tortuosity of flow channel is increased by the P-N, leading to a significant improvement in the purification efficiency. Notably, the P-N/Ag-Nylon composite membrane, fabricated by introducing AgNWs into the P-N, not only capitalizes on the inertia and gravity but also leverages electrostatic interactions to further enhance its adsorption capacity for PM2.5. At a voltage of 9 V, it achieves a pressure drop of 35 Pa with an impressive filtration efficiency of 99.49%. This work is expected to provide new perspectives on the microstructural design of air filtration materials with high purification efficiency.