Application of emulsion nanofluid membrane for the removal of methylene blue dye: stability study

Emulsion Liquid Membranes (ELMs) are effective techniques for separating metallic and organic compounds from aqueous solutions. Water in oil (W/O) emulsions are often distributed in wastewater (continual external phase) to generate the stable emulsion liquid membrane (W/O/W). Because of the large interfaces, ELM is known to have thermodynamic instability in membrane phases. In this study, we utilized highly stable Al2O3 nanofluid to the membrane phase along with the surfactant (Span 80) to develop the Emulsion Nanofluid Membrane (ENM). The highly stable ENM's liquid membrane phase was made up of Span 80 emulsified Kerosene (Carrier liquid), Al2O3 nanofluid, internal phase (NaOH and H2SO4), and external phases (Methylene blue-MB dye solution). At optimum conditions of 10 mL emulsion membrane volume, 100 mL external phase volume, 20 mL stripping phase volume, 1:2 stripping phase to membrane phase ratio, 3 min emulsification time, and 0.1 M NaOH stripping agent, and 0.03 Vol% of surfactant concentration a total extraction of 99% of MB can be achieved within the first 15 min. The current study provides a cost-effective scale-up and highly efficient simultaneous selective removal and recovery of industrial wastewater over typical separation operations.

Automated summary

In this study, a highly stable Emulsion Nanofluid Membrane (ENM) was developed using Al2O3 nanofluid and surfactant (Span 80) as the membrane phase. At optimal conditions, the ENM achieved a total extraction of 99% of Methylene blue (MB) within the first 15 minutes.