Abstract: The aim of this study was to design a new emulsion liquid membrane (ELM) system for the separation of succinic acid from aqueous solutions. The concentration of succinic acid varied from 20 to 60 mmol·L^-1. The prepared ELM system includes tributylamine (TBA) as a carrier, commercial kerosene as a solvent, Span 80 as a surfactant, and as a stripping agent. In order to control the membrane swelling, different values of cyclohexanone were added to the membrane phase. The effect of various empirical variables on the extraction of the succinic acid such as acid concentration in the feed solution, initial feed concentration, carrier concentration, the stirring speed of the extraction, , surfactant, and cyclohexanone concentrations, and treat ratio in the ELM system. The best result was obtained when TBA was used as the carrier. The final acid extraction efficiency was independent of pH variations of the aqueous feed solution. The extraction of succinic acid solution with a concentration of 40 mmol·L^-1 was improved by increasing the treat ratio 1:7–1:3, stripping phase concentration 0.5–1.5 mol·L^-1, stirring speed 300–500 r·min^-1 and cyclohexanone concentration in the membrane phase 1.2–1.6 mol·L^-1. No considerable effect on the extraction rate was observed for the carrier concentration in the membrane phase. But, the surfactant concentration in the feed phase showed a dual effect on the extraction efficiency.

Key words: Design, Membranes, Separation, Emulsion liquid, Succinic acid, Fermentation broth

摘要： The aim of this study was to design a new emulsion liquid membrane (ELM) system for the separation of succinic acid from aqueous solutions. The concentration of succinic acid varied from 20 to 60 mmol·L^-1. The prepared ELM system includes tributylamine (TBA) as a carrier, commercial kerosene as a solvent, Span 80 as a surfactant, and as a stripping agent. In order to control the membrane swelling, different values of cyclohexanone were added to the membrane phase. The effect of various empirical variables on the extraction of the succinic acid such as acid concentration in the feed solution, initial feed concentration, carrier concentration, the stirring speed of the extraction, , surfactant, and cyclohexanone concentrations, and treat ratio in the ELM system. The best result was obtained when TBA was used as the carrier. The final acid extraction efficiency was independent of pH variations of the aqueous feed solution. The extraction of succinic acid solution with a concentration of 40 mmol·L^-1 was improved by increasing the treat ratio 1:7–1:3, stripping phase concentration 0.5–1.5 mol·L^-1, stirring speed 300–500 r·min^-1 and cyclohexanone concentration in the membrane phase 1.2–1.6 mol·L^-1. No considerable effect on the extraction rate was observed for the carrier concentration in the membrane phase. But, the surfactant concentration in the feed phase showed a dual effect on the extraction efficiency.

关键词: Design, Membranes, Separation, Emulsion liquid, Succinic acid, Fermentation broth