Single-Layer Silica Nanosheets with In-Plane Porosity Enable High-Performance Nanolaminate Membranes for Organic Solvent Nanofiltration

Abstract

Organic solvent nanofiltration (OSN) membranes hold substantial promise for energy-efficient molecular separations in chemical and pharmaceutical industries, yet current technologies often face limitations in solvent permeation and precise sieving. To address these issues, we introduce novel nanolaminated membranes assembled from single-layer, two-dimensional (2D) mesoporous silica nanosheets with inherently uniform in-plane pores. These silica nanosheets, synthesized via a surfactant-templated soft approach, feature highly ordered and tunable hexagonal porosity with sub-10 nm thickness. By adjusting the surfactant carbon chain length, silica nanosheets with controllable pore dimensions were prepared and subsequently stacked into defect-minimized nanolaminate structures. The resulting membranes exhibited polarity-dependent solvent permeation, with permeance values up to 238 L m–2 h–1 bar–1 [LMHB] for polar solvents. Molecular sieving evaluations further revealed robust size-selective performance, achieving molecular weight cut-offs as low as 678 Da with high solvent flux. Remarkably, these nanolaminated silica membranes surpassed existing state-of-the-art OSN membranes in both permeability and selectivity benchmarks. Our findings underscore the potential of precisely engineered 2D mesoporous silica nanosheets as scalable and chemically robust building blocks for next-generation OSN membranes tailored for advanced molecular separation applications.