A comparative study of side-chain-type poly(ether ether ketone) anion exchange membrane functionalized with different hetero-cycloaliphatic quaternary ammonium groups

Effects of the Applied Potential on the Performance of Polysulfone Membranes Functionalized with Sulfonated Polyether Ether Ketone Polymers

The global water crisis growth has led to a tremendous increase in membrane technology research. Membranes are favored over many other technologies for water treatment because, in principle, they require no chemical additives and can be used isothermally at low temperatures. Membranes that can reject contaminants and salts, produce adequate permeate flux values, and require minimal cleaning are highly demanded. However, most synthesized membranes on the market have associated problems, such as membrane fouling; inverse relationships between flux and solute rejection; and the high cost of synthesis, operation, and maintenance. Therefore, there is a continuied need to produce membranes with properties that make them able to sustain flux and selectivity over time. This research study focused on increasing the surface charge and hydrophilicity of polysulfone (PSf) membranes by incorporating sulfonate-functionalized poly-ether-ether-ketone (SPEEK) into PSf/N-Methyl-2-pyrrolidone (PSf/NMP) membranes. The sulfonation of the PEEK provided a net increase in negative charge on the surface of the membranes that enabled charge repulsion to take place, thus increasing the rejection of ions. In this project, the effect of the applied potential on the performance of SPEEK: PSf/NMP membranes was evaluated. The characterization of the as-synthesized membranes was carried out using the surface's structure and morphology, contact angle, and zeta potential. Furthermore, a voltage of 1.5 V was applied to the membranes in the presence of various salts (sodium chloride, calcium chloride, and potassium chloride salts) to evaluate the effects of the applied potential on solute rejection. It was found that both the permeability and the selectivity of the membranes increased when the voltage was applied. The obtained results indicate that incorporating SPEEK into PSf/NMP membranes increased the hydrophilicity of the membranes, and under the applied voltage, the incorporation allowed it to function as an electrodialysis process that is capable of removing ions from water bodies by utilizing the charge repulsion of ions.

New block poly(ether sulfone) based anion exchange membranes with rigid side-chains and high-density quaternary ammonium groups for fuel cell application

We report a series of novel poly(ether sulfone) based anion exchange membranes (AEMs) with relatively good stability due to their rigid side-chains and heterocyclic quaternary ammonium groups. The AEMs show appropriate performance in AEM fuel cells.

Comb-shaped cardo poly(arylene ether nitrile sulfone) anion exchange membranes: significant impact of nitrile group content on morphology and properties

A series of comb-shaped cardo poly(arylene ether nitrile sulfone) (CCPENS-x) materials were synthesized by varying the content of nitrile groups as anion exchange membranes (AEMs). The well-designed architecture of cardo-based main chains and comb-shaped C10 long alkyl side chains bearing imidazolium groups was responsible for the clear microphase-separated morphologies, as confirmed by atomic force microscopy. The ion exchange capacity (IEC) of the AEMs ranged from 1.56 to 1.65 meq. g⁻¹. With strong dipole interchain interactions, the effects of nitrile groups on the membrane morphology and properties were investigated. With the nitrile group content increasing from CCPENS-0.2 to CCPENS-0.8, CCPENS-x revealed larger and more interconnected ionic domains to form more efficient ion-transport channels, thus increasing the corresponding ionic conductivity from 25.8 to 39.5 mS cm⁻¹ at 30 °C and 58.6 to 83 mS cm⁻¹ at 80 °C. Furthermore, CCPENS-x with a higher content of nitrile groups also exhibited lower water uptake (WU) and swelling ratio (SR), and better mechanical properties and thermal stability. This work presents a promising strategy for enhancing the performance of AEMs.

A series of comb-shaped cardo poly(arylene ether nitrile sulfone) (CCPENS-x) materials were synthesized by varying the content of nitrile groups as anion exchange membranes (AEMs).

Cationic ether-free poly(bis-alkylimidazolium) ionene blend polybenzimidazole as anion exchange membranes

A new simple route towards ether-free AEM design and fabrication with a wide potential structural scope.