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Main Title Effects of Humic Substances on Metal Speciation.
Author Perdue, E. M. ;
CORP Author Georgia Inst. of Tech., Atlanta. School of Geophysical Sciences.;Environmental Research Lab., Athens, GA.
Year Published 1987
Report Number EPA/600/D-87/351;
Stock Number PB88-133632
Additional Subjects Water treatment ; Metal complexes ; Humic acids ; Ligands ; Equilibrium ; Concentration(Composition) ; Metal ions
Library Call Number Additional Info Location Last
NTIS  PB88-133632 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 28p
The paper addresses some of the problems that must be understood and solved before the effects of metal-humic complexation on water treatment processes can be quantitatively addressed. The heterogeniety of ligands in a humic substance not only complicates the mathematical description of equilibrium data but also makes the complexation capacity of a humic substance almost impossible to accurately determine. Complexation capacities (meq/g) of humic substances are widely reported to vary with pH, ionic strength, concentration of the humic substances used in the measurement, and the nature of the metal being studied. The paper demonstrates that the reported effect of humic substance concentration on complexation capacity is an artifact, and that other effects arise from variations in conditional concentration quotients for metal complexation reactions.