Polyamide Nanofilms through a Non‐Isothermal‐Controlled Interfacial Polymerization

Abstract

Efficient thin film composite polyamide (PA) membranes require optimization of interfacial polymerization (IP) process. However, it is challengeable owing to its ultrafast reaction rate coupled with mass and heat transfer, yielding heterogeneous PA membranes with low performance. Herein, a non‐isothermal‐controlled IP (NIIP) method is proposed to fabricate a highly permeable and selective PA membrane by engineering IP at the cryogenic aqueous phase (CAP) to achieve synchronous control of heat and mass transfer in the interfacial region. The CAP also enables the phase transition of the aqueous solution from the liquid to solid state, providing a more comprehensive understanding of the fundamental mechanisms involved in different phase states in the IP process. Consequently, the PA membrane exhibits excellent separation performance with ultrahigh water permeance (42.9 L m−2 h−1 bar−1) and antibiotic desalination efficiency (antibiotic/NaCl selectivity of 159.3). This study provides new insights for the in‐depth understanding of the precise mechanism linking IP to the performance of the targeting membrane.

Bendable and Chemically Stable Metal–Organic Hybrid Membranes for Molecular Separation

“…Membrane-based separation technology has attracted significant attention in the process of purification and separation owing to its high separation efficiency, low operating cost, and process simplicity. − To further boost membrane separation performance, designing and synthesizing new membrane materials and developing feasible methods to assemble them into defect-free nanofilms with high selectivity and permeance are necessary. − An ideal membrane should possess high-density molecular-sized pores and a thin selective layer for low-resistance and highly selective permeation. − Additionally, high chemical stability is required to withstand harsh chemical environments during separation processes. − …”

Ion-Selective Transport Promotion Enabled by Angstrom-Scale Nanochannels in Dendrimer-Assembled Polyamide Nanofilm for Efficient Electrodialysis

“…The microstructure evolution of M-CEMs was examined using Doppler broadening spectroscopy (DBS). The S and R parameters were commonly used to investigate the changes in free volumes and microvoids of membranes, respectively. , Generally, in the quantitative DBS data, the S parameter represents the relative value of the free volume depth distribution in the polymer membrane, and the R parameter manifests the details of the occurrence of large pores (nm to μm). Specifically, the S values of dendrimer-assembled hybrid M-CEMs fluctuated around the value of 0.47 within the range of 2 keV of positron energy (a typical testing range for detecting the PA layer).…”