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X-RAY MICROSCOPY AND SPECTROSCOPY STUDIES ON METAL BINDING IN BIOSOLIDS (ABSTRACT)
Citation:
Hettiarachchi**, G. M. AND J A. Ryan*. X-RAY MICROSCOPY AND SPECTROSCOPY STUDIES ON METAL BINDING IN BIOSOLIDS (ABSTRACT). 2002 ASA-CSSA-SSSA Annual Meeting, Indianapolis, IN, 11/10-14/02.
Description:
Sorption/desorption data from intact and different fractions of biosolids and biosolids-amended soils indicated the importance of Fe and Mn fractions on both sorption and desorption of metals in biosolids and biosolids-amended soils. Extraction procedures used to separate organic C and Fe and Mn fractions are not completely phase specific/selective and may not provide definitive information on the phase(s) responsible for metals retention or the reaction "mechanisms". We employed X-ray microprobe analysis and micro-X-ray absorption spectroscopy at GSECARS, Advanced Photon Source, Argonne, IL to identify Fe and Mn phases and their association with metals in the intact and organic C removed biosolids samples. Elemental correlations derived with the information gathered from elemental mapping showed strong correlation between Fe and other metals (except Cu) before and after removal of organic C. Disappearance of Fe and Cu relationship after removal of OM suggests that Cu was possibly associated with OM coatings that may have been present on Fe compounds. Strong correlations between Mn and other metals were also observed. These microscopic observations support macroscopic observations (both laboratory and field) and indicate that Fe and Mn play and important role in metal retention in biosolids samples. This could be due to coprecipitation of these elements with Fe and/or Mn, adsorption of these elements onto Fe and/or Mn compounds, or combination of both of those mechanisms.