Modelling and simulation of integrated membrane processes for recovery of Cr(VI) with Aliquat 336

Recent advances in the separation of metals by liquid surfactant membranes are reviewed, with emphasis placed on development of a suitable surfactant. In establishing a metal recovery process using liquid surfactant membranes, the choice of a suitable surfactant is a key factor. It is important to elucidate the role of the surfactant on the behavior of liquid surfactant membranes, e.g., the break-up rate and the swelling rate of W/O emulsion globules in a mixer, the demulsification rate of the emulsions in an electrical coalescer and the extraction rate of metal by liquid surfactant membranes. These problems are discussed. The application of liquid surfactant membranes to the metal separation processes is also described

Recent Advances in Separation of Metals by Liquid Surfactant Membranes

Interfacial activity of metal ion extractant.

Using a newly synthesized surfactant, a kinetic study of copper extraction by liquid surfactant membranes containing anti-2-hydroxy-5-nonylbenzophenone oxime was carried out in a stirred tank, along with studies of the extraction equilibrium of copper with the extractant organic solution containing the surfactant and adsorption equilibrium of the surfactant between the organic and aqueous solutions at 303 K.The extraction rate by liquid surfactant membranes was analyzed by an interfacial reaction model between the carrier adjacent to the interface and the 1:1 copper chelate complex adsorbed at the interface. Furthermore, the change of extent of copper extracted with time was simulated by use of the constants of adsorption equilibrium and the interfacial reaction rate obtained from the analysis.

Extraction Kinetics of Copper with Liquid Surfactant Membranes Containing Lix65N and Nonionic Surfactant

The hydrophilic lipophilic balance of hydroxyoximes and the mechanism of copper extraction

The kinetics of the extraction of copper from sulphate media with a hydroxyoxime chelating extractant was studied using a single-drop technique. A simple kinetic scheme involving the species adsorbed at the aqueous-organic interface was proposed. Assuming the extreme conditions of chemical reaction control to apply, the extraction rates were found to be directly proportional to both copper (II) ion and monomeric oxime concentrations and inversely proportional to hydrogen ion concentration. These results support the reaction scheme proposed. The ratio of the rate constant for the n-heptane diluent system to that for the toluene diluent system was found to be as large as 20. This effect is thought to occur owing to the interfacial population density of adsorbed species and the free monomeric oxime content in the organic phase.

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Toshikazu Muraoka

Papers

Extraction kinetics of copper with hydroxyoxime extractant