Diffusion dialysis (DD) is an ion-exchange membrane (IEM) separation process driven by concentration gradient and has been applied for separation and recovery of acid/alkali waste solutions in a cost-effective and environmentally friendly manner.

Diffusion dialysis with ion-exchange membranes is mainly used today to recover acids or bases from a mixture with salts. The process is based on the fact that ion-exchange membranes generally show a high permeability for counterions while being more or less impermeable for co-ions. Exceptions are protons and hydroxide ions which can easily permeate both cation- and anion-exchange membranes. The transport mechanism in diffusion dialysis is more complex than in conventional dialysis due to the electrostatic interaction between positive and negative charges and the electroneutrality requirement。

Diffusion dialysis (DD) is an ion-exchange membrane (IEM) separation process driven by concentration gradient and has been applied for separation and recovery of acid/alkali waste solutions in a cost-effective and environmentally friendly manner.

Diffusion dialysis with ion-exchange membranes is mainly used today to recover acids or bases from a mixture with salts. The process is based on the fact that ion-exchange membranes generally show a high permeability for counterions while being more or less impermeable for co-ions. Exceptions are protons and hydroxide ions which can easily permeate both cation- and anion-exchange membranes. The transport mechanism in diffusion dialysis is more complex than in conventional dialysis due to the electrostatic interaction between positive and negative charges and the electroneutrality requirement。