A Two-Dimensional Lamellar Vermiculite Membrane for Precise Molecular Separation and Ion Sieving

Abstract

Lamellar membranes constructed from two-dimensional (2D) nanosheets have exhibited exceptional permselective characteristics. However, their complex and contaminative nanosheet synthesis, low structural stability, and low chemical resistance severely limit industrial-scale production and practical applications. Herein, the stability, molecular separation, ion-sieving properties, and broad applicability were evaluated to demonstrate the application potential of 2D vermiculite (VMT) nanomaterials in high-performance membrane development. First, the large-scale 2D VMT nanosheets with average lateral sizes of ∼12 μm were prepared from the widely occurring natural clay via a facile procedure, and the 2D lamellar VMT membrane showed excellent long-term stability in harsh environments, even in an ultrasonic bath. Furthermore, the VMT membrane showed fast solvent permeance with a favorable retention rate of dye molecules and a surface charge-governed ionic transport behavior because of the negatively charged nanochannel, indicating the potential in both molecule separation and ion sieving. Moreover, the broad applicability of the VMT membrane was also confirmed using a simple intercalation optimizing strategy developed for other 2D membranes. Building on these findings, our work shows a possible route to the development of advanced membranes for energy and environmental applications.