Sorption is a physical and chemical process by which one substance becomes attached to another. Specific cases of sorption are treated in the following articles:

Absorption

"the incorporation of a substance in one state into another of a different state" ;

Adsorption

The physical adherence or bonding of ions and molecules onto the surface of another phase ;

Ion exchange

An exchange of ions between two electrolytes or between an electrolyte solution and a complex.