Effect of nanoparticles on interfacial mass transfer characteristics and mechanisms in liquid-liquid extraction by molecular dynamics simulation

Abstract The addition of nanoparticles is a promising strategy to intensify interfacial mass transfer, which possess a wide array of potential applications in considerable industrial processes. In order to elucidate interfacial mass transfer characteristics and mechanisms, the effects of functional group, particle size and volume fraction of silica nanoparticle on dimethyl sulfoxide (DMSO) transfer across the water/hexane interface were investigated by molecular dynamics simulation. The results manifested that hydrophilic nanoparticles are beneficial to mass transfer enhancement. Due to the increase of mass transfer path and steric hindrance of nanoparticles at the liquid-liquid interface, however, hydrophobic and amphiphilic nanoparticles inhibit solute mass transfer. Moreover, the smallest size nanoparticle at the maximum concentration of 10 vol% leads to the highest enhancement, namely the decrease of mass transfer resistance by 36%. By analyzing the mean square displacement and size effect of nanoparticle, it is found that Brownian motion rather than micro-convection is probably the dominant mechanism.