Organic solvent composite nanofiltration membrane based on poly(m-phenylene isophthalamide) (PMIA) substrate

Organic solvent nanofiltration (OSN) technology, which can achieve efficient separation of small molecules without phase change and greatly reduce energy consumption, is of great significance in contributing to the goal of ‘carbon neutrality’. The separation performance of OSN membranes directly affects the efficiency of the OSN process. Thin film composite (TFC) membranes prepared by interfacial polymerization (IP) have high ion selectivity and permeability. In this study, TFC membranes were prepared using poly(m-phenylene isophthalamide) (PMIA) as the substrate with excellent thermal and chemical stability, and piperazine (PIP) and trimesoyl chloride (TMC) as the reactive monomers. The effects of different IP conditions on the properties of TFC membranes were systematically studied. The experimental results showed that the optimized TFC membranes exhibited good water flux (57.6 L·m −2 ·h −1 ) and Na 2 SO 4 rejection (99.6 %) with a selectivity of up to 200 for monovalent and divalent salts (NaCl/ Na 2 SO 4 ) at 0.5 MPa. Notably, the membrane demonstrated stable ethanol permeance over a 60-hour continuous test. At the same time, the PMIA-PA TFC NF membrane can remain stable in alcohols, alkanes, ketones, benzenes, as well as acid and alkali solvents after one week, with strong solvent resistance