Investigation on process parameters of soybean oil-based Emulsion liquid membrane for Cr(VI) removal from aqueous acidic solutions

The focus of this study is the extraction of hexavalent chromium from wastewater using emulsion liquid membranes (ELM) in a way that contributes to green chemistry. It is to explore the possibility of replacing the fossil-fuel based diluent in the ELM for a renewable vegetable oil. It proposes a novel ELM formulation consisting of the renewable material soybean oil as the vegetable diluent. The mobile carrier TOMAC is included in the membrane to facilitate the metal transport. Span 80 is used as surfactant. The system achieved a removal efficiency of hexavalent chromium of over 98% when having an optimal concentration of surfactant and carrier concentrations and an agitation speed of 400 rpm. Three important factors influencing the extraction were found to be the emulsion formulation, the agitation speed, carrier concentration and surfactantconcentration. Nevertheless, other factors such as solute concentration of feed,Ph of the external phase, stripping phase concentration and contact time were regarded in a constant level. The stability of the ELM is crucial and needs therefore further investigations.

Keywords:

Green emulsion liquid membrane , Cr(VI) removal , Soybean oil , TOMAC