Biomimetic Core-Shell-Structured Nanofiber Membranes for Rapid and Portable Water Purification

Rapid and portable water purification (RPWP) technologies, helping travelers survive in the wild, have attracted increasing interest due to increasing activities, such as exploration, field hiking, and excursion. Field water is usually pathogenic because of various soluble and insoluble contaminants. In this study, fish-gill-like biomimetic core-shell-structured nanofiber membranes are designed and synthesized by an in situ oxidation polymerization coating process. A polyimide nanofiber membrane and a polypyrrole (PPy) coating layer are employed as a core and shell, respectively. The biomimetic membranes exhibit dual-functional capacities: a rapid removal of insoluble contaminants owing to the highly porous network and broad-spectrum adsorption of soluble contaminants enabled by the PPy shell. Model studies confirm the excellent ability of the membranes to purify Cr(VI)-contaminated water to drinkable water with a safe capacity of ∼1415 L m^-2. Actual application tests show that the membrane can efficiently remove coliform and suspended solids in a muddy water sample taken from a river in Suzhou, China. This study provides a promising route for the design of a single-layer membrane with dual functions for highly efficient RPWP.