Effect of micelles on flotation of metal ions

"A study of the anionic surfactant, sodium dodecyl sulfate (SDS), and the dependency of the adsorption of divalent metal counterions such as copper and zinc at the air-water interface on its concentration in the solution, was undertaken in order to better understand the process of ion flotation. The study is divided into two broad categories, the first of which consists of the evaluation of the extent of aggregation of the surfactant molecules into micelles, and the effect of the divalent metal counterion concentration on this aggregation and on the critical concentration at which micelles start forming (cmc). This was accomplished using well established light scattering and surface tension techniques, which were also used in the investigation of the influence of surfactant concentration on the precipitation of lead dodecyl sulfate. The adsorption of divalent counterions at air-water interfaces comprised the second category of this research, and it was conducted using conventional equilibrium surface tension measurements and an established foaming technique. The following conclusions were drawn: 1) The adsorption of divalent metal counterions at air-water interfaces, and therefore, the flotation of these ions is largely independent of the type of divalent counterion. 2) Optimum flotation conditions for divalent counterions occur in surfactant solutions containing no micelles. Since the stability of the foam, a desirable feature in ion flotation, increases with the concentration of the surfactant, the best conditions for ion flotation occur at the cmc. 3) The competing adsorption of the divalent metal counterions at the micellar shear interface is primarily responsible for the decrease in the adsorption of these counterions at the air-water interface. 4) The competing adsorption of divalent lead counterions at the micellar shear interface is apparently responsible for the increase in the solubility of Pb(DS)₂ in concentrated sodium dodecyl sulfate (SDS) solutions. It was possible to propose a theory, based on the potential calculations of the electrical double layers of flat and spherical surfaces, which correlated most of the observations made in this research"--Abstract, page ii-iii.

Name thesis:degree_name

Ph. D. in Metallurgical Engineering

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Oko, Uriel Michael

• Metallurgy

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/1980

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-2982