| This thesis focuses on the recent theoretical and experimental developments in the area of high gradient magnetic separation (HGMS). The first four chapters are devoted to study and proof the feasibility of using magnetite in HGMS processes, which was motivated by a from very interesting experimental results obtained at the Rocky Flats Environmental Technology Site. With the authors help, it was concluded that ferromagnetic iron oxides (i.e., magnetite) are far more effective as a ferromagnetic element than stainless steel wool for retaining nanoparticles. In support of these findings, the feasibility and limitations of a novel nanolevel HGMS process utilizing magnetite in a fixed bed mode were investigated. Chapters two and three study the effect of the magnetic force acting both alone and coupled with the most relevant non-magnetic forces, such as convective, electrostatic, van der Waals and Brownian forces for the case where one magnetite particle is interacting with one paramagnetic nanoparticle. The effect of the magnetic force acting alone was further investigated in chapter four for the case where multiple magnetite particles are interacting with one paramagnetic nanoparticle. The last two chapters (i.e., chapters five and six) of this thesis are devoted more to the area of traditional HGMS, that is, where stainless steel is used as the magnetizable element for separation. Chapter five, for example, focuses on the development of a new correlation for the capture cross section, a very important parameter in HGMS dynamics, over the entire range of variables meaningful to HGMS in aqueous media, while chapter six concentrates upon the use experimental and theoretical studies of HGMS for the retrieval and concentration of suspended solids from aqueous solutions. |
