Patent ID: 8858821

Claim:
A method of producing magnetic extractants comprising: i) dissolving in an aqueous medium a salt of Fe (II) chloride and a salt of Fe (III) chloride in about 2:3 mole ratio, while mixing, to form an aqueous solution of FeCl 2 and FeCl 3 ; ii) adding to the aqueous solution a base at conditions sufficient to increase a pH to about 8-10 which causes precipitation of magnetite nanoparticles; iii) washing the precipitated magnetite nanoparticles to remove excess amount of any undesired ions; iv) drying the magnetite nanoparticles; v) grinding the dried magnetite nanoparticles, and vi) functionalizing the dried and ground magnetite nanoparticles, that have extensive hydroxyl groups, by subsequently treating the magnetite nanoparticles with a silane reagent containing functional groups or a polymer to produce magnetic extractants, wherein the dried and ground magnetite nanoparticles are functionalized by placing the dried and ground magnetite nanoparticles having negative charge in one or more hybridization tubes and adding to the one or more hybridization tubes a toluene or xylene solution of a silane reagent containing functional groups or a polymer, rotating the one or more hybridization tubes in an oven at a temperature of 60° C. for a time sufficient so that substantially all or all residues of the hydroxyl groups are bound with the silane reagent containing functional groups or a polymer, the magnetic extractants are isolated by filtration and washed with toluene to remove unattached molecules of are the silane reagent containing functional groups or a polymer and dried at 60° C., and the dried and ground magnetite nanoparticles have a specific surface area (SSA) of about 47 m 2 g.