The effects of the surfactants on the extraction rate of nickel(II) and palladium(II) with 2-(5-bromo-2-pyridylazo)-5-diethyaminophenol (5-Br-PADAP) in the toluene/water system were investigated by the centrifugal liquid membrane (CLM) method. The extraction rates of the metal(II) ions were increased by the addition of the ionic surfactants having a charge opposite to the metal(II) species in the aqueous solution. The stronger the interfacial activity of the surfactant, the larger the acceleration effect became. The acceleration was explained by the increase in the interfacial concentration of metal ions by an electrostatic attraction between the metal species and the ionic surfactant adsorbed at the interface. On the other hand, the extraction rates of metal(II) ions were reduced by the addition of an ionic surfactant having the same charge as the metal(II) species and the nonionic surfactant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.