Phenol recovery and removal from aqueous solutions by emulsion liquid membranes

Abstract

Emulsiontype liquid membrane process is a new and effective method for separation ofmixtures with applications in the nuclear industry, hydrometallurgy andwastewater treatment. The emulsified liquid membrane is made by forming anemulsion of two immiscible phases and then dispersing the emulsion in a thirdphase (i.e. continuous or feed phase). Phenol is mainly found in thewastewaters of such industries as petroleum refineries and petrochemicals. Inaddition phenol is also contained in the wastewaters of industries of resins,explosives, paper, plastics, glass and rubbers. Numerous solvent extractiontechniques using various ligands are also used as commercial in such processesas hydrometallurgy and wastewater treatment. However one of the disadvantage ofsolvent extraction is the necessity of solvents and ligands of large quantities.Water-oil-water (W/O/W) type of liquid membrane system provides excellentseparation techniques and thus this causes a substantial reduction in the amount ofligands and solvents, Liquid membrane phase consist of a surfactant (Span 80)and solvent (kerosene). In this study the most important parameters thatprovide the extraction of phenol from aqueous solutions and their effect onextraction efficiency were examined by liquid membrane process. Theseparameters are determined to be as membrane viscosity, treatment ratio (feedvolume/emulsion volume), surfactant concentration, feed concentration and pH,mixing speed and phase ratio (stripping solution volume / membrane volume). Thephenol was extracted from the aqueous feed solutions in which phenolconcentration ranged from 100 to 550 mg/L. Optimum parameters were found to beas: 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 feedsolutions could be removed from the solution It has been possible that thephenol concentration were reduced from 550 mg/L to 5-10 mg/L within twominutes.

Keywords

• emulsion liquid membranes; phenol recovery; phenol removal; 4-aminoantipyrine; phenol extraction; span 80