STRUCTURAL MECHANICAL PROPERTIES OF HUMIC SUBSTANCES USED AS COMPONENTS OF MAGNETIC NANOCOMPOSITES

摘要

This study is devoted to investigation of plasto-viscoelastic properties of soluble humate hydrogels with the aqueous medium pH 6-7, obtained by neutralizing relevant alkaline extracts by various acid solutions, and insoluble humates of polyvalent metals. The comparative study of the structure formation processes in gels of soluble sodium and potassium humates with pH 6-7, containing a mineral salt, shows that the dispersed medium composition affects plasto-viscoelastic properties of the coagulation medium. When potassium humates contain KNO_3 salts, the CCS value compared to a gel without KNO3 reduces from 17% to 13.6% of the dispersed phase, thereby enhancing the structure. In potassium humates, the NaNO_3 salt has an opposite action, i.e., it deteriorates the structure formation properties; compared to a gel without NaNO_3 the CCS increases from 10% to 14% of the dispersed phase, reducing the strength of the coagulation structure. The produced samples of insoluble iron (Ⅲ) humates are the products of incomplete substitution of the Na~+ ion from the acid groups of the soluble form of humic acids. The structure formation capacity of the hydrogel with the H~+ form of humic acids is expressed much weaker compared to hydogels of iron humates. This is demonstrated by the high CCS value (22% of the dispersed phase) and the low values of the strength parameters at CCS.