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CAER Seminars

MERCURY REMEDIATION FROM AQUEOUS AND AIRBORNE SOURCES

Speaker:
Dr. David Atwood
University of Kentucky
Chemistry Department

Date:
Wednesday, August 11, 1999 3:30 pm
Ben Bandy Conference Center
Center for Applied Energy Research

Abstract:
The seminar will cover three areas: the use of commercial precipitants for Hg, our own proposed systems for this application, and the use of nanoparticulate materials as gas-phase Hg(0) adsorbants.

Many compounds have been marketed to precipitate Hg from industrial waste effluents and natural waters. We have found that the manufacturers may not always provide critical information on the chemistry and stability of the precipitates and when they do, the information may be incorrect. I will demonstrate that the commercial remediation agents, Thio-Red(Etus, Inc.) and TMT-55 (trimercaptotriazine, Degussa, Inc.) are not useful in remediating mercury and other metals from aqueous sources. The precipitates that formed in using these reagents decompose to release the metal or other toxic compounds (CS2, for instance). Of more fundamenal interest, we have discovered some interesting coordination chemistry of the TMT ligand.

We are also exploring the synthesis of new ligands that can bind mercury, either as Hg0, MeHg+, or Hg2+, irreversibly, in a tetrahedral geometry. Ideally, the ligand will be sufficiently robust that it may be used as a precipitant with Hg. Alternatively, the ligand may be appended to a polymer support for filtration applications.

We have demonstrated that nanoparticulate alumina can be formed at ambient conditions using a unique molecular precursor. This precursor may be functionalized to include thiolate groups, leading to the possibility of preparing Al2OxS3-X nanoparticulate materials. It is hoped that these new sulfide containing materials may be used as absorbants (or chemisorbants) for gaseous Hg(0).