Electron spin resonance investigation of copper(II) complexation by fulvic acid extracted from sewage sludge

Journal Article · Tue Jan 01 00:00:00 EST 1985 · Soil Sci. Soc. Am. J.; (United States)

DOI:https://doi.org/10.2136/sssaj1985.03615995004900010024x· OSTI ID:6293772

Senesi, N; Bocian, D F; Sposito, G

Electron spin resonance (ESR) spectra are reported for copper(II)-fulvic acid complexes prepared with fulvic acid (FA) samples extracted from two different anaerobically-digested sewage sludges. In the original Cu-FA solutions, quadridentate, nearly square planar complexes with FA donor ligands could be inferred from the ESR spectra only at the smallest Cu/FA molar ratio, whereas at the intermediate ratios mixed Cu-FA-H2O complexes became more evident and at the highest ratio free CuS aquo-ions prevailed. The ESR spectra suggested the formation of inter-sphere, polydentate complexes, with the Cu(II) coordinated equatorially by oxygenated and nitrogenated FA ligands. No saturation of the Cu(II) complexation capacity was observed, but increasing the Cu content involved less and less reactive functional groups of FA in the coordination, shifting the complexation equilibria towards the formation of weaker complexes. A significant rearrangement of the Cu-FA systems was suggested to take place upon air-drying.

• Research Organization: Univ. di Bari, Italy
• OSTI ID: 6293772
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Vol. 49:1
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
COPPER
COMPLEXES
ELECTRON SPIN RESONANCE
FULVIC ACIDS
ION EXCHANGE
SEWAGE SLUDGE
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
ELEMENTS
MAGNETIC RESONANCE
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
RESONANCE
SEWAGE
SLUDGES
TRANSITION ELEMENTS
WASTES
510200* - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)
510100 - Environment
Terrestrial- Basic Studies- (-1989)