Structure-performance relationship in tailored poly(amide-sulfone) membranes for desalination

Poly(amide-sulfone)s were considered the missing link for water desalination membranes, owing to their exceptional properties resulting from the synergism effects of two amide and sulfone structures. To achieve this, a sulfone-based diamine was first synthesized by reacting 4,4′-dichlorodiphenyl sulfone with 3-aminophenol. Subsequently, alternative copolymers of poly(amide-sulfone) were prepared via polycondensation reactions of the synthesized diamine monomer and various diacid chlorides including adipoyl dichloride, isophthaloyl dichloride, and terephthaloyl dichloride. The chemical structures were approved using Fourier transform infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy. Porous membranes of the polymers as substrates were prepared by solution casting and phase-inversion method. To form thin film composite membranes, a thin polyamide layer was created through interfacial polymerization on the top surface of prepared substrates using m-phenylenediamine and trimesoyl chloride. After characterization, the performance of all membranes was assessed by evaluating pure water flux, NaCl rejection, and flux recovery ratio using a cross-flow filtration system. The impact of the amide group within the poly(amide-sulfone) substrate structure on thin-film efficiency was explored. Results, revealed that the structure significantly influenced membrane performance. Specifically, the highest pure water flux was 549.50 L.m⁻².h⁻¹. Also, NaCl rejection of 98.27 % and flux recovery ratio of 94.21 % were observed among them at pressure of 10 bar. This study provided valuable insights for developing novel poly(amide-sulfone) membranes tailored for desalination applications.