EMT-NH 2 zeolite nanocrystal interlayer induces the formation of high-performance polyamide membrane with heterogeneity morphology
Résumé
Conventional nanofiltration (NF) thin-film composite (TFC) membranes are strongly restricted by the trade-off between their water permeance and selectivity as well as the poor structural stability for desalination and wastewater treatment. Herein, we report an interlayer-based thin-film composite (i-TFC) NF membrane with high performance using amino-functionalized EMT zeolite (EMT-NH 2) nanocrystals as the interlayer. By adjusting the distribution density of EMT-NH 2 on the substrate, a thin and dense PA layer with heterogeneity multi-level morphology (nanosized nodules and nanoscale stripes) can be formed and regulated. The EMT-NH 2 zeolite nanocrystals with numerous hydrophilic groups (hydroxy and amino groups) and internal cavities can provide an additional priority water channel, increase the amine monomer storage on the substrate, and slow down the diffusion of amine monomer, thereby leading to the construction of a dense PA layer with high performance. As a result, the i-TFC-15 membrane depicted a water permeability of 13.82 ± 0.47 L m-2 h-1 ⋅bar-1 (2.5 times that of the controlled one), while maintaining an excellent retention ability for divalent salts (98.55% for Na 2 SO 4 , 98.42% for MgSO 4 and 97.40% for MgCl 2). Additionally, the rigid hydrophilic interlayer containing zeolite nanocrystals endowed the i-TFC-15 membrane with excellent pressure resistance (up to 2.4 MPa), long-term operating stability, and antifouling propensity (flux-recovery ratio, 90.1%). This work provides an approach for fabricating a novel high-performance NF membrane and deepens our understanding of the role of porous interlayer affecting the formation of the PA layer.
Domaines
Chimie
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