Carboxylated polysulfone (CPS), poly (1,4-phenylene ether ethersulfone) (PPEES), membranes were prepared and used for the separation of NaCl and CaCl 2, in efficient way with less energy consumption. In this work, nanofiltration and reverse osmosis membranes were employed to the salt rejection behavior of the different salt solutions. The influence of applied pressure (1-12 bar), on the membrane performance was assessed. In CM series of membranes, CM 1 showed maximum of 97% water uptake and 36% water swelling, whereas, CM 4 showed 75% water uptake and 28% water swelling. In RCM series, RCM 1 showed 85% water uptake and 32% water swelling whereas, in RCM 4 it was 68% for water uptake and 20% for water swelling. Conclusively reverse osmosis membranes gave better rejection whereas nanofiltration membrane showed enhanced flux. CM1 showed 58% of rejection with 12 L/(m 2 h) flux and RCM 1 showed 55% of rejection with 15 L/(m 2 h) flux for 0.1 wt.% NaCl solution. Whereas, in 0.1 wt.% CaCl 2 solution, membrane CM 1 showed 78% of rejection with 12 L/(m 2 h) flux and RCM 1 showed 63% rejection with flux of 9 L/(m 2 h).

In the recent years membrane technology has gained significant attention from polymer chemists all around the world due to their attractive features such as efficiency, low costs, low energy costs and as effective solutions to longstanding problems in the chemical industries. Membrane technologies have been widely applied in the separation of liquids and even gases. Many separation problems can be solved economically by nanofiltration alone or in combination with other separation processes. This study aimed to synthesize polysulfone based nanofiltration membranes using DIPS (diffusion induced phase separation) technique. Newly synthesized polymer membranes were subjected to Infra red spectral and water uptake studies. Membranes were also characterized using electrochemical spectroscopy for their proton conducting property. Their surface morphology is visualized by SEM.

The title mol­ecule, C7H7Cl2N3OS, is approximately planar [maximum deviation = 0.062 (1) Å]. Short inter­molecular distances between the centroids of the five-membered rings [3.5340 (8) Å] indicate the existence of π–π inter­actions. An inter­esting feature of the crystal structure is the presence of short intra­molecular Cl⋯N inter­actions [3.0015 (11) Å]. Mol­ecules are linked via pairs of inter­molecular N—H⋯O hydrogen bonds, generating R 2 2(8) ring motifs. Furthermore, N—H⋯O hydrogen bonds form R 2 1(7) ring motifs with C—H⋯O contacts, further consolidating the crystal structure. In the crystal, mol­ecules are linked by these inter­molecular inter­actions, forming chains along [001].

In the title compound, C11H13N5OS, the dihedral angle between the triazole ring and the benzene ring is 84.21 (7)°. The amino group adopts a pyramidal configuration. An intra­molecular N—H⋯O hydrogen bond stabilizes the mol­ecular structure and generates an S(8) ring. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O, N—H⋯S, N—H⋯N and C—H⋯S hydrogen bonds into layers lying parallel to the bc plane. The crystal structure is further stabilized by aromatic π–π stacking inter­actions [centroid–centroid distance = 3.3330 (7) Å].

In the present study, carboxylated polysulfone (CPS) and Poly (1,4–phenylene ether ether–sulfone) (PPEES) NF membranes for their application in proton exchange membrane fuel cells (PEMFCs) were investigated. New NF membranes were prepared by blending PPEES with CPS solution in NMP (5 wt. %) by the solution casting procedure using K–control coater. The membranes have been characterized by thermal analysis, water uptake, IEC measurements, proton conductivity performance and methanol crossover. Electrochemical impedance spectroscopy (EIS) was at length used to decide proton conductivity. The addition of CPS increased the water uptake capability of the synthesized membrane and resulted in enhanced proton conductivity. The conductivity values in the range of 10–4 –10–2 S/cm were obtained for the new CPS–PPEES membranes. The conductivities of the membranes showed increasing trend as a function of operating temperature and wt. % of CPS. Membrane of the type CM1 gave the conductivity in the range of 0.12 S/cm at 100°C. The results showed that, CPS/PPEES is a promising membrane material for possible use in proton exchange membrane fuel cells.