[gsf_emergency_2]

Here's one way

https://en.wikipedia.org/wiki/Ion-exchange_membrane

Another, that you might be interested in, but it's more confusing

https://en.wikipedia.org/wiki/Proton-exchange_membrane

[gsf_emergency_2]

See the figure

https://www.fuelcellstore.com/introduction-ion-exchange-memb...

Each ion of salt participates in a different reaction