Efficient removal of Indigo dye from aqueous solution by an innovative method of emulsion liquid membrane

Abstract

Extraction of Indigo dye from aqueous solution is studied in this research using Emulsion Liquid Membrane (ELM). Water/Oil (W/O) emulsion was prepared by mixing aqueous phase with organic phase at an elevated homogenizing speed. H2SO4 and Hexane were used as internal stripping agent and organic diluent respectively. Monooleate Sorbitan commonly known as Span-80 was used as surfactant in organic phase. This W/O emulsion was later mixed with external feed phase containing Indigo dye to make W/O/W double emulsion. Stability of the membrane was optimized by experimenting different operating parameters. The ELM prepared under the optimum conditions was finally used to remove Indigo dye from aqueous solution. The parametric study of the process parameters affecting the extraction efficiency was also performed. Under optimum conditions of parameters like volume ratio of emulsion/feed, dye concentration in feed, stirring speed and contact time of two phases, the extraction of Indigo dye was found to be 99%. Therefore, ELM was found to be an attractive and effective technique for the removal of dyes.