Thermodynamic Characteristics of the Reactions of Formation of Iron and Magnesium Humates in Aqueous Solution

The thermodynamic stability of iron and magnesium ions at different acidity of an aqueous medium was determined using chemical thermodynamics methods and Pourbaix diagrams. The temperature dependence of the thermodynamic functions of corresponding reactions was calculated. The thermodynamic feasibility of the reactions of replacing potassium and sodium ions in aqueous solutions of humic acid salts containing carboxyl and hydroxyl functional groups with iron and magnesium ions was established. The resulting water-soluble iron and magnesium humates can have a high potential for practical use.