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SORPTION OF LEAD ON A RUTHENIUM COMPOUND: A MACROSCOPIC AND MICROSCOPIC STUDY
Citation:
Scheckel*, K G., C A. Impellitteri**, AND J A. Ryan*. SORPTION OF LEAD ON A RUTHENIUM COMPOUND: A MACROSCOPIC AND MICROSCOPIC STUDY. Presented at American Institute of Chemical Engineers 2002 Annual Meeting, Indianapolis, IN, 11/3-8/2002.
Description:
The objective of this study was to elucidate the sorption mechanism of Pb on the high-affinity ruthenium compound with time at pH 6 employing batch methods and X-ray absorption fine structure (XAFS) and X-ray diffraction (XRD) spectroscopies. For the spectroscopic studies, Pb sorbed ruthenium samples were analyzed in-situ via XAFS to determine bond distances, coordination numbers, and identity of nearest neighbors and as a freeze-dried powder for XRD to detect changes in the crystal structure of the ruthenium compound. The results of the kinetic batch experiments show that Pb sorption is extremely rapid with greater than 90% removal from a 0.4M Pb(NO3)2 (8288 ppm) solution within one hour. The ruthenium phase possesses a sorption capacity of 800,000 mg Pb per kg of solid, which far exceeds the sorption capacity of typically employed iron, manganese, and aluminum oxides. XAFS data indicate that the Pb is sorbed as a tightly bound inner-sphere complex. XRD studies show that the high coverage of Pb diminishes the characteristic peaks for the ruthenium compound through the sorption mechanism on the solid surface and may indicate incorporation into the ruthenium structure. Initial studies of the ruthenium compound have shown great promise as a treatment option for removal of metals and oxoanions from solution. Further studies are ongoing to better understand the interaction of the ruthenium compound with these environmental contaminants.