Sulfide and iron work together to reveal a new path for radionuclide sequestration

Aug 01, 2013
Sulfide and iron work together to reveal a new path for radionuclide sequestration
Sifting radionuclides with sulfur: Technetium sequestration pathways under sulfidogenic conditions stimulated by nZVI offer a possibly more sustainable, environmentally friendly approach to bioremediation.

As an ongoing concern for the Department of Energy's Office of Biological and Environmental Research (DOE-BER), bioremediation strategies that either remove contaminants or retard their mobility in the environment are long-sought-after solutions. Technetium-99, an isotope generated from nuclear fission stemming from Manhattan Project-era plutonium processing, is among the high-priority radionuclides requiring environmental controls.

In one approach to tackle this problem, scientists measured reduction of soluble (99TcO4?) by nano zerovalent iron (nZVI) that had been pre-exposed to sulfide (S2-) in simulated Hanford Site groundwater. nZVI promotes microbial reduction of sulfate (SO42-) to S2- and offers a promising and sustainable method for generating S2- in the environment.

Their work, using a mix of microscopy-, diffraction-, and spectroscopy-aided assessments and conceptual modeling, was designed to provide a fundamental geochemical understanding of Tc sequestration as new sulfide compounds developed in the presence of nZVI, as well as offer an alternative remediation strategy. The scientists examined the evolution of mineral phases during the changing sulfidation states using a mix of EMSL's capabilities and X-ray (XAS) at the Stanford Synchrotron Radiation Lightsource (SSRL).

They coupled this work to Tc sequestration kinetics under incremental sulfur/iron ratios. Their results showed the importance of iron sulfide in Tc sequestration and how sulfidation of nZVI can direct TcO4? sequestration products from Tc(IV) oxide—which is highly susceptible to reoxidation—to Tc(IV) sulfide phases, providing a more favorable sequestration pathway.

Explore further: Spider's web weaves way to advanced networks and displays

More information: Fan, D. et al. 2013. Reductive Sequestration of Pertechnetate (99TcO4–) by Nano Zerovalent Iron (nZVI) Transformed by Abiotic Sulfide, Environmental Science & Technology 47(10):5302-5310. DOI: 10.1021/es304829z.

add to favorites email to friend print save as pdf

Related Stories

Hospital scanner could curb nuclear waste threat

Jan 29, 2010

Medical equipment used for diagnosis of patients with heart disease and cancer could be a key weapon in stopping nuclear waste seeping into the environment, according to new research.

Recommended for you

The simplest element: Turning hydrogen into 'graphene'

Dec 16, 2014

New work from Carnegie's Ivan Naumov and Russell Hemley delves into the chemistry underlying some surprising recent observations about hydrogen, and reveals remarkable parallels between hydrogen and graphene ...

Future batteries: Lithium-sulfur with a graphene wrapper

Dec 16, 2014

What do you get when you wrap a thin sheet of the "wonder material" graphene around a novel multifunctional sulfur electrode that combines an energy storage unit and electron/ion transfer networks? An extremely ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.