A study on natural and synthetic humic acids and their complexing ability towards cadmium

• Published in: Plant and soil Vol. 235; no. 1; pp. 115 - 125
• Main Authors: Datta, A., Sanyal, S.K., Saha, S.
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01-08-2001; Springer; Springer Nature B.V
• Subjects: Acid soils; Acids; Agricultural soils; Agrology; Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Cadmium; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Humic acids; Humus; Molecular weight; Organic soils; Phenols; Pollution; Pollution, environment geology; Soil and sediments pollution; Soil and water pollution; Soil biochemistry; Soil organic matter; Soil science; Soils; Surface tension; Viscosity; Aromaticity; Cadmium II Ions; Hydrophobicity; Soil pollution; Structure function relationship; Humus; Hydroxyl group; Micropollutant; Soil interaction; Chemical properties; Constituent; Ability; Cadmium; Complexation; Laboratory study; Pollutant behavior; Organomineral complex; Stability constant; Natural compound; Heavy metal; Organic chemistry; Synthetic product; Chemical reaction; Macromolecule; Phenols; Cadmium complex; Humic acid; Conformation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/A:1011842019753

The natural and synthetic humic acids were characterised by potentiometric titrations, viscosity and surface tension measurements, as well as visible spectometry The results have been correlated with coiling-decoiling behaviour and aliphatic-aromatic balance of these acids. The stability constant of complexes formed by these humic acids with Cd²⁺ ions in aqueous phase was evaluated by the ion-exchange method. Results tend to suggest that humic phenolic -OH group was involved in the formation of Cd²⁺ -humic complex, leading to it the given stability in a manner as for the analogous metal-oxine complexation. The hydrophobic moiety of the synthetic humic acid may also provide a cage-type conformation around Cd²⁺ ion, imparting to the Cd²⁺ -humic complex the desired stability.