Application of emulsion liquid membrane for removal of malachite green dye from aqueous solution: Extraction and stability studies

Malachite green (MG) dye has various applications as a dyeing material, medical disinfectant and biocide but is also recognized as a teratogenic, carcinogenic, mutagenic and respiratory toxic material which creates dire effects on human beings, aquatic flora and fauna. Hence, the main objective lies in the removal of MG dye from an aqueous stream. In the current investigation, emulsion liquid membrane (ELM) technique was used and the effect of different factors like concentration of carrier, surfactant, stripping phase and its type and volume ratio of membrane to stripping solution on the removal of MG dye were studied. MG extraction efficiency of 94.99% was achieved using emulsion consisting of 2% w/v Span 80, 2% w/v D2EHPA, 0.1 N HCl and membrane phase to stripping phase volume ratio 1. Microscopic studies of the emulsion revealed the formation of well-defined and large number of globules with very less coalescence which resulted in high removal of MG dye. The physical stability of the emulsion was analysed and the phase separation was comparatively less at various time intervals suggesting that the conditions used for preparing the emulsions are suitable. Fourier transform infrared spectroscopy established the bonding and presence of various functional groups. The current study intends to fulfill the gap by exploring the removal of MG dye by ELM technique.