BR-08 Synthesized and Commercial Iron Sulfide Particles as Contaminant Sorbents
Creators: Nabil Ashraf Shuvo
John Bussey
Arumala J. Lere-Adams
M. C. Dixon Wilkins
Sam Karcher
John McCloy
Publisher: name: IEEE
Year: 2025

Magnetic nanoparticles are used for wastewater treatment, chemical separation, and theranostic medicine. Their magnetic nature allows particle movement after capturing or delivering chemical agents. Normally for magnetic separation, iron oxide (usually magnetite) or zero-valent iron particles with surface-attached ligands are used. Bare particles have advantages, however, preventing moment reduction by ligands and allowing access to the reducing nature of iron species on the surface. Herein, nanoparticles of iron sulfide, nominally greigite (Fe3S4) but including other iron sulfides (pyrite, pyrrhotite), target the removal of radionuclide elements from aqueous solutions simulating radioactive liquid waste. Target radioisotopes, 99Tc and 129I, are highly mobile in groundwater at contaminated sites, and their half-lives drive long-term environmental doses for some radioactive waste disposal sites. Thus, it is advantageous to separate them from liquid streams and sequester them elsewhere. Greigite particles here are synthesized by several methods – a) mechano-synthesis, b) hydrothermal, c) solvothermal, and d) biological routes. Synthesized particles are compared with commercially obtained iron sulfides, for phase fractions via X-ray diffraction (XRD), magnetic properties via vibrating sample magnetometry (VSM), and morphologies via scanning electron microscopy (SEM), Fig. 1. Select Fe-S material shows sorbing of perrhenate (pertechnetate surrogate) as evidenced Raman vibrational modes of dissolved ions, Fig 2a,b. Additionally, tests investigating sorbent effects on iodate solution showed a strong reduction by Fe-S, changing the solution from clear to red, producing I3- ions and some FeI2 precipitate, Fig. 2c.
Magnetic nanoparticles are used for wastewater treatment, chemical separation, and theranostic medicine. Their magnetic nature allows particle movement after capturing or delivering chemical agents. Normally for magnetic separation, iron oxide (usually magnetite) or zero-valent iron particles with surface-attached ligands are used. Bare particles have advantages, however, preventing moment reduction by ligands and allowing access to the reducing nature of iron species on the surface. Herein, nanoparticles of iron sulfide, nominally greigite (Fe3S4) but including other iron sulfides (pyrite, pyrrhotite), target the removal of radionuclide elements from aqueous solutions simulating radioactive liquid waste. Target radioisotopes, 99Tc and 129I, are highly mobile in groundwater at contaminated sites, and their half-lives drive long-term environmental doses for some radioactive waste disposal sites. Thus, it is advantageous to separate them from liquid streams and sequester them elsewhere. Greigite particles here are synthesized by several methods – a) mechano-synthesis, b) hydrothermal, c) solvothermal, and d) biological routes. Synthesized particles are compared with commercially obtained iron sulfides, for phase fractions via X-ray diffraction (XRD), magnetic properties via vibrating sample magnetometry (VSM), and morphologies via scanning electron microscopy (SEM), Fig. 1. Select Fe-S material shows sorbing of perrhenate (pertechnetate surrogate) as evidenced Raman vibrational modes of dissolved ions, Fig 2a,b. Additionally, tests investigating sorbent effects on iodate solution showed a strong reduction by Fe-S, changing the solution from clear to red, producing I3- ions and some FeI2 precipitate, Fig. 2c.