foam fractionation
A method of separation in which a component of the bulk liquid is preferentially adsorbed at the liquid/vapour (L/V) interface and is removed by foaming.
PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 609 (