Vermiculite-driven Turing structures on polyamide membranes with enhanced water flux and ion rejection

Abstract

Achieving high water permeance while maintaining effective solute rejection remains a critical challenge in polyamide membranes, primarily due to structural inhomogeneities created by conventional interfacial polymerization. Here, we merge diffusion-driven Turing patterning with infrared-assisted water evaporation to achieve better control over its diffusion, addressing this inherent limitation. A nanometer-thin, biodegradable 2D vermiculite gutter layer was used to precisely reduce the monomer diffusion, triggering the “local activation-lateral inhibition” instability that leads to the formation of large area, tube-shaped Turing patterns cloaked in nanobubbles. These periodic patterns enlarge the active area and shorten the transport paths, yielding a pure-water flux of 155 ± 15 L.m−2.h−1 while simultaneously achieving > 91 % rejection of divalent salts and > 97 % rejection of an organic dye, demonstrating robust performance across both inorganic and organic contaminants. The striped Turing architecture also allows eleven-fold Li+/Mg2+ selectivity, enabling efficient lithium recovery from salt-lake brines. This approach offers a powerful platform for the development of high-performance, ion- and molecule-selective membranes with significant potential for sustainable water treatment and resource recovery applications.