Date of Award
M.S. in Engineering Science
Adam E. Smith
University of Mississippi
Predicting the behavior of magnetic surfactants in magnetic fields is critical for designing magnetically driven processes such as chemical separations or the tuning of surface tensions. Our work supports the hypothesis that the ability of magnetic fields to alter the interfacial properties of magnetic surfactant solutions depends on the strength of association between the magnetic and surfactant moieties of the surfactant molecules. Our research shows that the stability of a magnetic surfactant in an aqueous environment is dependent upon the type of complex that contains the paramagnetic element and these findings provide valuable insight for the design of magnetic surfactants for applications in aqueous media. The surfactants investigated were ionic surfactants which contained paramagnetic counterions. This investigation looked at both anionic and cationic surfactants and utilized solution conductivity cyclic voltammetry (CV) sampled current voltammetry (SCV) and solution pH measurements to qualitatively evaluate the stability of the magnetic counterions in aqueous solution. In addition solution conductivity was used to quantify the degree of binding between the parmagnetic ions and surfactant micelles in solution. These results indicate metal halide-based cationic surfactants are unstable in aqueous solutions. We hypothesize that this instability results in the difference in the magnetic response of anionic vs. cationic surfactants examined in this study. To address the growing energy demands of our society we investigated magnetic surfactants and their potential application to low energy separations processes. The research described in this work details our investigation of the stability of unimeric magnetic surfactants in aqueous solution and our investigation of magnetically enhancing the solubilization capacity of magnetic amphiphilic polymers for low energy separations processes. We believe that this work is critical to the growing body of research that involves magnetic amphiphiles. To our knowledge increasing the solubilization capacity of magnetically responsive amphiphilic by exposing them to parallel magnetic fields has not been investigated before. If this were possible it could be exploited in the design of a low energy separation process. Herein we report the synthesis of two kinds of magnetic polymeric amphiphiles which form micelles in water and we investigated their relative solubilization capacities in aqueous solutions inside and outside of parallel magnetic fields for three organic contaminants. The organic contaminants were: toluene naphthalene and anthracene. We utilized UV-VIS spectroscopy as our method of detection of the relative concentrations of the contaminants. We did not detect an increase in the solubilization capacity of the polymers for toluene or anthracene when they were placed inside of a parallel magnetic field although our results indicated that the solubilization capacity of the polymers for naphthalene increases when the samples are exposed to a parallel magnetic field of approx. 0.6 T. Using our results we speculate about the future design of magnetic amphiphiles and we believe that our work contributes to the growing body of research in this field.
Fortenberry, Alexander, "Magnetic amphiphiles and their potential applications for low energy separations processes" (2019). Electronic Theses and Dissertations. 1735.