In this study, we present a highly stable vegetable oil
ionic liquid
(IL)-based emulsion liquid membrane (VOILELM) for the removal of lactic
acid from water streams. The system developed as a part of this work
comprises a non-ionic surfactant Span 80, sodium hydroxide as an internal
stripping agent, sunflower canola oil as a green diluent, and IL—tetramethylammonium
acetate [TMAm][Ac]—as a carrier. VOILELM stability was evaluated
in terms of breakage, emulsion diameter, and standalone stability.
The effect of various parameters, namely, concentration of the surfactant,
concentration of the internal stripping agent, concentration of the
carrier, phase ratio, homogenizer speed, and homogenization time,
on the VOILELM stability was studied. The results revealed that VOILELM
was highly stable, with 1.34% minimum breakage, 1.16 μm emulsion
diameter, and 131 min standalone stability. The optimal process parameters
were 0.1 wt % Span 80, 0.1 M NaOH, 0.3 wt % IL, 0.25 phase ratio,
5000 rpm homogenizer speed, and 5 min homogenization time. At these
optimized conditions, 96.08% lactic acid extraction efficiency was
achieved. Thus, a highly effective VOILELM was developed, with minimal
breakage and emulsion diameter and maximum stability.