Abstract:

Emulsion type liquid membrane process is a new and effective method for separation of mixtures with applications in the nuclear industry, hydrometallurgy and wastewater treatment. The emulsified liquid membrane is made by forming an emulsion of two immiscible phases and then dispersing the emulsion in a third phase (i.e. continuous or feed phase). Phenol is mainly found in the wastewaters of such industries as petroleum refineries and petrochemicals. In addition phenol is also contained in the wastewaters of industries of resins, explosives, paper, plastics, glass and rubbers. Numerous solvent extraction techniques using various ligands are also used as commercial in such processes as hydrometallurgy and wastewater treatment. However one of the disadvantage of solvent extraction is the necessity of solvents and ligands of large quantities. Water-oil-water (W/O/W) type of liquid membrane system provides excellent separation techniques and thus this causes      a substantial reduction in the amount of ligands and solvents, Liquid membrane phase consist of a surfactant (Span 80) and solvent (kerosene). In this study the most important parameters that provide the extraction of phenol from aqueous solutions and their effect on extraction efficiency were examined by liquid membrane process. These parameters are determined to be as membrane viscosity, treatment ratio (feed volume/emulsion volume), surfactant concentration, feed concentration and pH, mixing speed and phase ratio (stripping solution volume / membrane volume). The phenol was extracted from the aqueous feed solutions in which phenol concentration ranged from 100 to 550 mg/L. Optimum parameters were found to be as: pH = 4; phase ratio, ϕ = 1; mixing speed (300 rpm); 3 % Span 80 and 2 % NaOH. Under the suitable conditions, about 96 % of the phenol in the feed solutions could be removed from the solution It has been possible that the phenol concentration were reduced from 550 mg/L to 5-10 mg/L within two minutes.

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