Premium
Cupric Ion Complexation by Fulvic Acid Extracted from Sewage Sludge‐Soil Mixtures
Author(s) -
Sposito Garrison,
Holtzclaw Kenneth M.,
LeVesqueMadore C. S.
Publication year - 1979
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/sssaj1979.03615995004300060018x
Subject(s) - potentiometric titration , chemistry , titration , denticity , sewage sludge , inorganic chemistry , ion , nuclear chemistry , sewage , organic chemistry , crystal structure , engineering , waste management
The complexes formed between Cu 2+ and fulvic acid extracted from sewage sludge were investigated by potentiometric titration of K/H fulvate with Cu(ClO 4 ) 3 at pH 5 and 25°C, in an ionic medium of 0.1 M KClO 4 . Formation functions, giving the number of moles of Cu 2+ bound per mole of K/H fulvate, were calculated from the titration data and plotted against the molar concentration of Cu 2+ , with the concentration of K/H fulvate being a fixed parameter for each plot. These functions were analyzed by the Scatchard plot method and were interpreted as evidence of: ( i ) a relatively strong 1:1 complex (log c K = 3.9) that is formed between Cu 2+ and the most acidic functional groups in fulvic acid and ( ii ) a weaker set of complexes (log e K = 2) that is formed between Cu 2+ and the more weakly acidic functional groups acting as both unidentate and bidentate ligands.