Cr (VI) being a toxic and carcinogenic pollutant should be removed from industrial effluents. In the present investigation, Cr (VI) was transported selectively with Cyanex 923 carrier from bulk feed phase to internal stripping phase using emulsion liquid membrane technique. The liquid membrane was prepared by loading with Cyanex 923 as the carrier, Span 80 as the surfactant, kerosene as the solvent and sodium hydroxide as the stripping agent and their effect on the process parameters such as concentration of the surfactant, the ratio of organic phase to internal phase in the membrane and membrane to external phase ratio were studied using Box-Behnken design and response surface method. A quadratic polynomial regression equation was used to analyze the experimental data. The experimental and predicted values were in good agreement. The experimental results showed that chromium ion was extracted within 5 min. The chromium ion concentration was measured using inductively coupled plasma mass spectrometry (ICP-MS). (C) 2010 Elsevier B.V. All rights reserved.