Work

Thermally stable Ti-hybrid layer solvent-tolerant nanofiltration membranes functionalized via atmospheric-pressure molecular layer deposition

Year: 2026

Type: article

Abstract: Solvent-tolerant nanofiltration (STNF) provides an energy-efficient approach for the separation and recovery of solutes from industrial water–solvent streams. This study investigates atmospheric-pressure molecular layer deposition (AP-MLD) for the fabrication of thermally stable titanium-hybrid (Ti-hybrid) ceramic membranes for STNF. Ti-hybrid layers were deposited on tubular porous ceramic supports at 125 °C using 900 AP-MLD cycles and subsequently annealed in air at 350 °C for 4 or 8 h. Microstructural analysis showed uniform Ti distribution throughout the modified membrane layer, while Fourier-transform infrared spectroscopy indicated no significant changes in the characteristic Ti- and C-related functional groups following exposure to water–solvent mixtures. Membrane stability was evaluated, for 24h of total exposure, by measuring demineralized water permeance before and after exposure to 9:1 (v/v) water–dimethyl sulfoxide (DMSO), water–2-propanol (IPA), and water– N,N -dimethylformamide (DMF) mixtures at 25 and 60 °C. The membranes exhibited pore diameters <2 nm, >90% rejection of polyethylene glycol with molecular weights >420 Da, and a water permeance of 21 ± 2 L m⁻² h⁻¹ bar⁻¹. Stable performance was maintained during exposure to the investigated water–solvent mixtures, with permeances of 20–28 L m⁻² h⁻¹ bar⁻¹ at 60 °C. While the 4 h annealed membrane showed changes following exposure to water–DMF at elevated temperature, extending the annealing time to 8 h improved the stability of the Ti-hybrid network. These results demonstrate that AP-MLD-derived Ti-hybrid layers provide a promising route toward high-permeance, thermally stable ceramic membranes for STNF applications.

Source: Journal of Membrane Science Letters

DOI: 10.1016/j.memlet.2026.100131