Emulsion liquid membranes phenol removal

Lin CC and Long RL. Phenol removal by emulsion liquid membrane A modified diffusion model. Chem Eng Comm 1996 156 45-58. 

Park, Y., SkeUand, A.H.P., Forney, L.J. and Kim, J.H. (2006). Removal of phenol and substituted phenols by newly developed emulsion liquid membrane process. Water Res., 40, 1763-72. 

Emulsion liquid membranes have been formulated for the removal of species without chemical carriers. These systems rely on solubility differences between permeant species. The first work performed by Li (73) dealt with the separation of a bineiry mixture of aromatic eind paraffinic hydrocarbons. The hydrocarbons were encapsulated in an aqueous liquid membrane forming an emulsion which was distributed in a hydrocarbon solvent and mixed. The aromatic hydrocarbons preferentially permeated through the aqueous liquid membrane phase due to solubility differences. Cahn and Li (7 ) describe a liquid membrane formulation for phenol removal in which sodium hydroxide is encapsulated by an organic liquid membrane. The resulting membrane phase is mixed with a continuous aqueous phase containing phenol. 

In Chapter 15, Ho and Li briefly review recent advances in the theory for emulsion liquid membranes and applications in more detail. Commercial applications include the removal of zinc, phenol, and cyanide from wastewaters. Potential applications in wastewater treatment, biochemical processing, rare earth metal extraction, radioactive material removal, and nickel recovety are described. 

Phenol and Ammonia Recovery. Finally, the closely related passive and fa-cilitated-transport processes for phenol and ammonia recovery should be mentioned. In these processes, dilute phenol or ammonia feed solutions are contacted with a liquid membrane in which they are freely soluble. They dissolve in the membrane, diffusing to the product side where they are removed by neutralizing with a base (in the case of phenol) or an acid (in the case of ammonia). Although the transport mechanism does not involve a carrier and these are, therefore, passive transport processes, the actual process is quite similar, and Li et al25 published the details of these separations using emulsion membrane technique. 

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