Chemical synthesis, processing, and characterization of nanostructured Fe-B for the magnetically assisted chemical separation of hazardous waste

Nanostructured Fe-B alloys have been synthesized by reducing aqueous FeCl2 with potassium borohydride both in the presence and in the absence of an ap plied magnetic field and investigated for the separation of hazardous waste in the magnetically assisted chemical separation (MACS) process. Linear ch ain and discrete particle microstructures of Fe-B are obtained depending on the reaction conditions. The Fe-B samples exhibit a saturation magnetizati on as high as 190 emu/g after annealing in a 90%Ar-10%H-2 atmosphere at 400 degreesC. The Fe-B magnetic materials are then encapsulated within a unifo rm polyacrylamide matrix using a solution-based technique developed in this study. With an optimum surfactant concentration, homogeneous Fe-B/polyacry lamide composite materials could be readily prepared. The particle size of the composite could be controlled by varying the monomer concentration duri ng the polymerization. Laboratory level testing with a surrogate species (c obalt ions) indicates that these materials are highly suitable for the MACS process. For example, partitioning coefficient values greater than 6000 an d 8200 mL/g are obtained at pH = 6.5 for the composites based on Fe-B chain and particle microstructure, respectively.