Complexation between metal ions and water soluble organic soil substances as analyzed by electrochemical techniques

• Published in: Moscow University soil science bulletin Vol. 68; no. 1; pp. 41 - 47
• Main Authors: Makarychev, I. P., Motuzova, G. V.
• Format: Journal Article
• Language: English
• Published: Heidelberg Allerton Press, Inc 01-03-2013; Springer Nature B.V
• Subjects: Conductivity; Earth and Environmental Science; Earth Sciences; Geochemistry; Historical Geology; Ions; Metals; Paleontology; Soil Chemistry; Soil sciences; conductometric titration; metal ion complexation; potentiometric titration; differential equivalent electrical conductivity of solutions
• ISSN: 0147-6874; 1934-7928
• DOI: 10.3103/S0147687413010055

Conductometric and potentiometric titration of water extracts from soils using metal salt solutions (Cu, Al, Pb) were performed. A nonlinear dependence of electrical conductivity of water extracts on the concentration of metals added was established, which is caused by the formation of metal organic complexes proceeding with the participation of metal ions. A parameter describing the differential equivalent electrical conductivity (Δλ) was proposed which characterizes the complexation process, and a formula for the calculation of this parameter was given. The basic parameters of copper ion complex formation with water soluble organic substances of the extract were determined on the basis of conductometric titration of water extracts from soils using copper nitrate solution. These processes were shown to proceed differently for soddy and podzolic soils, the properties of which are known to differ significantly. An integrated parameter of the equivalent electrical conductivity for ligands of soil water soluble organic substances was assessed.