Adsorption accumulation and separation of dissolved substances in dry foams

The theoretical and experimental studies devoted to the peculiarities of foam adsorption accumulation and separation of substances occurring in the liquid phase in molecular, ionic, or micellar form in polyhedral (dry) foam are discussed. The main characteristics of foam concentration and separation, their analytical dependences on the structural parameters of the foam, and their interdependences are analysed. Quantitative relationships for the characteristics of foam concentration/separation with due regard to the influence of foam destruction have been obtained. The dependences of the accumulation coefficient on the expansion factor and dispersity of the foam and also on the capillary pressure in polyhedral (dry) foams prepared from solutions of individual surfactants and their mixtures are analysed. The reasons for accumulation restrictions (upper and lower limits) of the foam concentration method are discussed. Special mode of concentration taking place in dynamic foam leading to accumulation of surfactant in the top foam layer is discussed. New approaches to modelling continuous foam fractionation with reflux are considered. Examples of partial separation of surfactants in foam are considered.