Interlamellar adsorption of a blackearth humic acid on Na-montmorillonite

Abstract

Interaction between clay and organic compounds has been extensively studied and a considerable amount of literature is available. So, for example, reaction with glycerol (1), ethyleneglycol (7) and dimethylsulfoxide (3) are very well known. But there are not many papers dealing with the reaction between clay and organic matter of soil. Recently, Greenland (4) has made an interesting rewiew of this event. Reactions between clay minerals and fulvic acid have been reproduced in a number of publications, but there are very little papers about interaction between clay minerals and humic acid, probably due to the difficulty to get humic acid in solution. Schnitzer and Kodama (10) have been made an intensive study on the reaction between a Podzol fulvic acid and Na-Montmorillonite, and they have found that the fulvic acid was adsorbed in the interlamellar spaces of the clay. They found also, that the adsorption was dependent on pH, clay mineral/fulvic acid ratio and time of contact.