Supported liquid membranes membrane-controlled type

Equilibrium-restricted reactions (Section A9.3.3.1) have until now been the main field of research on CMRs. Other types of application, such as the controlled addition of reactants (Section A9.3.3.2) or the use of CMRs as active contactors (Section A9.3.3.3), seem however very promising, as they do not require permselective membranes and often operate at moderate temperatures. Especially attractive is the concept of active contactors where the membrane being the catalyst support becomes an active interface between two non-miscible reactants. Indeed this concept, initially developed for gas-liquid reaction [79] has been recently extended to aqueous-organic reactants [82], In both cases the contact between catalyst and limiting reactant which restricts the performance of conventional reactors is favored by the membrane. 

The alternating electrostatic layer-by-layer adsorption of polyionic compounds has been proven to be a simple, yet elegant and versatile technique for preparation of films with controlled structure and uniform thickness in the nanometer range [1-3]. The method is also useful for the preparation of a new type of composite membrane with ultrathin separation layer, if cationic and anionic polyelectrolytes are alternately adsorbed on a porous support [4-11]. First attempts to use these membranes for separation of gases [4-6], liquid mixtures [7-10] and ions [8, 11] have already been reported. 

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