Ultrathin Cellulose Voronoi-Nanonet Membranes Enable High-Flux and Energy-Saving Water Purification

Creating a desirable porous membrane with high-flux and energy-saving properties for the purification of water containing submicron-sized contaminants, especially pathogenic microbes, is of great significance, yet a great challenge. Herein, we demonstrate a facile methodology to construct an innovative membrane with continuous cellulose Voronoi-nanonet structures via nonsolvent-induced phase separation. This approach enables cellulose Voronoi nanonets to tightly weld with electrospun nanofibrous substrates by controlling the solvent–nonsolvent mutual diffusion process. The resultant membranes exhibit integrated properties of small pore size (0.23 μm), high porosity (90.7%), good interconnectivity, and ultrathin thickness (∼600 nm, 2 orders of magnitude thinner than the conventional microfiltration membrane). As a result, the prepared membranes can effectively intercept submicron particles (∼0.3 μm) with robust rejection efficiency (>99.80%) and ultrahigh permeation flux (maximum of 8834 L m–2 h–1) under an extremely low driving pressure (≤20 kPa). More importantly, prominent bacterial rejection efficiency with a log reduction value (LRV) of 8.0 (overcoming the previous limitation of LRV <7) and outstanding antifouling function are also achieved for the membranes. The successful fabrication of such a versatile membrane may provide new insights into the development of next-generation high-performance separation materials for various applications.