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Copper(II) Binding by Humic Acid Extracted from Sewage Sludge: An Electron Spin Resonance Study
Author(s) -
Boyd Stephen A.,
Sommers Lee E.,
Nelson Darrell W.,
West Douglas X.
Publication year - 1983
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1983.03615995004700010008x
Subject(s) - electron paramagnetic resonance , chemistry , ethylenediamine , glycylglycine , humic acid , adduct , copper , ligand field theory , inorganic chemistry , nuclear chemistry , crystallography , ion , nuclear magnetic resonance , amino acid , organic chemistry , fertilizer , physics , glycine , biochemistry
Electron spin resonance (ESR) spectroscopy was used to study the binding of Cu 2+ by humic acid (HA) extracted from sewage sludge. Electron spin resonance spectral data of the Cu‐HA complex and some adducts with nitrogen donors (pyridine, 1,10‐phenanthroline, ethylenediamine) showed that Cu 2+ formed two equatorial bonds with HA oxygen donor ligands. The ESR data presented were consistent with the formation of a Cu‐chelate in the original Cu‐HA complex. The ligand field strength of the HA oxygen donor ligands coordinated to Cu 2+ was stronger than that of H 2 O. The above results were consistent with an earlier ESR characterization of a soil Cu‐HA complex. The Cu 2+ ion also appeared to form axial bonds with HA donor ligands originating from proteinaceous materials associated with the sludge HA fraction. Characterization of an adduct with glycylglycine showed that the dipeptide formed coordinate honds with Cu 2+ bound to HA.