Novel magnetic extractants for removal of pollutants from water

Abstract

Scope and Method of Study: This research aims at developing magnetic extractants that can be utilized in conjunction with magnetic filtration devices to efficiently and economically remove a number of pollutants from aqueous solutions and mixtures. Two types of magnetic materials were synthesized, characterized, and used in a variety of environmental applications. The first was based on activated carbon, where raw materials used for the development of high surface area activated carbon were modified to produce novel magnetically-active activated carbons (MAC's). The unique properties and adsorption capacity of these materials allowed their application in the extraction of hydrocarbons from water and in breaking oil in water emulsions. In the second phase of the project, nano-composites of organic-capped magnetite and nickel ferrite were successfully obtained by non-hydrolytic thermal treatment of organometallic precursors. The nanoparticles were characterized using a variety of techniques including transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Finally, an investigation on the ability of the nanoparticulate extractants for the removal of 4,6-dinitro-o-cresol pesticide and arsenate from water was conducted.

Findings and Conclusions: Magnetic activated carbons prepared from industrial and household byproducts were effective for the removal of decane, 4,6-dinitro-o-cresol, arsenate, and a number of dyes from aqueous media. Additionally, MAC's were capable of breaking oil in water emulsions. Carboxylate capped magnetic nanoparticles were easily synthesized, and exhibited unique properties such as structural uniformity, small size, and high surface area. These nanoparticles showed remarkable results in the removal of 4,6-dinitro-o-cresol pesticide and arsenate from water. Moreover, magnetic activity exhibited by these extractants allowed for quick separation using magnetic filters.

Potential applications include rapid cleanup of oil spills, treatment of waste waters, separation of lipids from serum samples for medical analysis and as an alternative to liquid/liquid extraction in chemical and drug manufacturing.