Extraction performance of bisphenol A from aqueous solutions by emulsion liquid membrane using response surface methodology

In this work, the extraction of bisphenol A (BPA) from aqueous solutions by emulsion liquid membrane (ELM) was investigated using response surface methodology (RSM). The organic membrane phase of the ELM consisted of a solvent (kerosene) and a surfactant (OP-4). The internal phase was sodium hydroxide (NaOH) solution with varying concentrations. Optimum conditions for stable emulsion were found out experimentally. The effects of the important operating variables on the BPA extraction were investigated and the values of these variables were optimized using the Central Composition Design (CCD) of RSM. These variables are the concentration of surfactant OP-4 in organic membrane phase, the treatment ratio (volume ratio of external phase to ELM phase, Rwe), the concentration of NaOH in internal phase and the volume ratio of organic membrane phase to internal phase (Roi). The 3D response surfaces of BPA extraction efficiency were obtained. The result shows that, under the optimum conditions, the observed BPA extraction efficiency of 97.52% can be achieved. Heat-induced demulsification was successfully conducted and the recycled membrane phase was proved to be effective.

► Process variables were optimized through response surface methodology.
► Membrane leakage analyzed by detecting the pH of external phase was very low.
► BPA extraction efficiency by emulsion liquid membrane with OP-4 as surfactant can reach 97.52%.
► Heat-induced demulsification was proved to be effective.