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Emulsion liquid membrane technique (ELM) was used for the extraction of phenol from synthetic and industrial effl uents. In this study, the liquid membrane used for phenol removal was composed of kerosene as the solvent, Span-80 as the surfactant and Sodium hydroxide as an internal reagent. Statistical experimental design was applied for the optimization of process parameters for the removal of phenol by ELM. The effects of process parameters namely, Surfactant concentration, membrane or organic to internal phase ratio (M/I) and emulsion to an external phase ratio (E/E) on the removal of phenol were optimized using a response surface method. The optimum conditions for the extraction of phenol using Response surface methodology were: surfactant concentration -4.1802 %, M/I ratio: 0.9987(v/v), and E/E ratio: 0.4718 (v/v). Under the optimized condition the maximum phenol extraction was found to be 98.88% respectively.

In the present work, experiments have been carried out with a focus to reduce the volume requirement of solvent by mixing with imidazolium based ionic liquids (ILs) for the solvent extraction of phenol, p‐chlorophenol, 2,4‐dichlorophenol, 2,4,6‐trichlorophenol, and pentachlorophenol from aqueous solutions. The effect of aqueous phase pH (2–12), agitation speed (100–450 rpm), solute concentration in feed (2–50 mg/L), temperature (303–333 K), treat ratio (1–11), and 1‐butyl‐3‐methyl imidazolium tetrafluoroborate [Bmim]+[BF4]− volume in tributyl phosphate (TBP; 0–0.7% v/v) on extraction of phenols has been studied and optimized. Parameters like strip phase pH (3–13) and stripping agent concentration (0.001–0.009 N) have also been studied for stripping of phenols from solvent phase. It has been found that 0.5% v/v of ionic liquid [Bmim]+[BF4]− in solvent TBP extracts more than 97.5% of phenol and chlorophenols from aqueous solutions with a treat ratio (aqueous to solvent phase ratio) of 5. Transport mechanism for extraction and stripping of phenol and chlorophenols using ionic liquid [Bmim]+[BF4]− has been discussed. The results show that by appropriate selection of extraction and stripping conditions, it is possible to remove nearly all phenols with a treat ratio of 5.

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Copper and zinc were removed from dilute aqueous solutions together with recovery of copper from electroplating wastewater containing copper ions by emulsion liquid membrane (ELM) technique. The effects of surfactant concentration, carrier concentration, emulsification speed, emulsification time, internal phase stripping agent concentration, and aqueous-to-organic phase (A/O) volume ratio on the emulsion stability and breakup have been studied in detail and reported. A mixture of kerosene as diluent, span 80 as surfactant, di-(2-ethylhexyl) phosphate as carrier was used. An experimental study was performed to optimize the pH of the aqueous external phase based on distribution coefficient of solute between aqueous external phase and organic (membrane) phase. The batch extraction was carried out under various experimental conditions such as agitation time, agitation speed, membrane-to-external phase (M /E ) ratio, solute concentration in the feed phase and carrier concentration in membrane phase on the percentage recovery of zinc and copper ions in their respective feed streams and the operating parameters have been optimized for maximum recovery. It was found that 84% of copper and 86% of zinc were removed from aqueous solution with a concentration factor of 5. It was also found that ELM extraction of copper from wastewater was around 8-17% less than that of the synthetic solution. 