Fabrication and Performance of Novel Poly(piperazine-amide) Composite Nanofiltration Membranes Based on Various Poly(m‑phenylene isophthalamide) Substrates

In this research, polypiperazine-amide (PA) thin film composite (TFC) nanofiltration membranes were successfully prepared via an interfacial polymerization technique atop poly­(m-phenylene isophthalamide) (PMIA) supports, which were prepared via the phase separation method. The systematical effects of PMIA substrates’ properties on TFC membranes were first investigated by varying the PMIA concentration. The morphological structure, physicochemical characteristics, and filtration performance of substrates and TFC membranes were evaluated by a series of analytical technologies. Also, results revealed that the changes in PMIA substrate properties had a significant influence on PA barrier layer formation, mainly including PA thickness, topography, pore size, and separation performance. In addition, considering both flux and retention ability to different salts, TFC membranes developed upon the substrate with 14% PMIA concentration exhibited excellent performance.