Simultaneous effect of nanoparticles and surfactant on emulsion liquid membrane: Swelling, breakage and mean drop size

Abstract

In this study, the effect of multi-walled carbon nanotubes (MWCNTs) and Span-85 as a surfactant on drops breakup and coalescence rates of emulsion liquid membrane (ELM) due to hydrodynamic parameters was investigated which was not reported before. A single stage horizontal mixer-settler extractor with two 4-pitched blade turbine impellers with 45° inclined blades on one shaft was employed. The influences of MWCNTs, Span-85 and both of them at the same time on membrane swelling and breakage were studied in batch mode and dispersion Sauter mean diameter (D32) was compared to pure system for continuous mode experiments. Results indicated that simultaneous presence of MWCNTs and surfactant enhanced the ELM stability and the membrane swelling and breakage decreased about 46% and 63%, respectively. Also, it has the most influence on drop size compared to the presence of Span-85 and MWCNTs alone, respectively. Presence of MWCNTs and Span-85 at the same time caused to reduction in enhancing rate of D32 with dispersed phase volume fraction about 65.5%. Additionally, decreasing rate of D32 with impeller agitation speed diminished about 1.4%. Furthermore, in order to predict a mean drop size for all systems (with and without inorganic particles), a new modified correlation was proposed for the first time where the surfactant and nanoparticles concentrations were introduced as new independent parameters.