Ultrathin SiO2 Nanofibrous Membranes with Voronoi-like Nanonets for High-Flux Water Filtration and Elution-Free Microplastics Analysis

Abstract Inorganic microfiltration membranes are essential for water purification and microplastics detection; however, achieving high-flux water treatment and enabling straightforward microplastics analysis remain global challenges due to the limitations in the self-supporting nature and structural tunability of inorganic materials. Here, inspired by Voronoi-like natural structures, we report a route to create silicon dioxide (SiO2) nanofibrous membranes with a Voronoi-like nanonet structure (SiO2 VNMs), in which humidity-regulated phase separation and curing generate organosilicon-derived nanonets from silicone oil solution on electrospun and calcined SiO2 fibrous scaffolds. Subsequent calcination converts the organosilicon-derived nanonets into SiO2 nanonets. Benefiting from the self-organized Voronoi-like nanonet architecture, the resulting SiO2 VNMs simultaneously exhibit small pore sizes (≈150 nm), high porosity (≥80%), and an ultrathin thickness (≈1 μm). Consequently, the SiO2 VNMs deliver high filtration flux at low pressure (>6600 L m –2 h–1 at 15 kPa), and even under gravity-driven conditions (>900 L m–2 h–1 at 0.1 m H2O), exceeding that of existing inorganic membranes (6200 L m–2 h–1 at 70 kPa), rivaling the best state-of-the-art organic membranes. Moreover, the ultrathin inorganic structure enables direct on-membrane microscopic and spectroscopic identification of microplastics without elution. This work establishes a new pathway for designing inorganic filtration membranes that integrate efficient water purification with streamlined on-membrane microplastics detection.