Preparation and properties of fulvic acids of low-mineralized peloids

Low-mineralized sulphide silt muds have high biological activity; they produce both local and general effects on the body. Fulvic acids (FA) are less understood components of peloids; they are difficult to study due to their high mineralization when isolated by classical methods. In this regard, it is relevant to find new methods for obtaining FA and determine their constitutional parameters. The aim of the work was to obtain fulvic acids of peloids with a low degree of mineralization and to determine some physical and chemical parameters. FA were isolated from low-mineralized sulphide silt muds using reprecipitation. Elemental analysis of FA samples was carried out with a Evro 300 CHN analyzer; IR spectra were recorded with an FSM 1201 IR Fourier spectrophotometer; molecular mass distribution was carried out by gel filtration, self-diffusion coefficients were determined with NMR with a magnetic field pulsed gradient; adsorption isotherms of water vapor were obtained in a vacuum adsorption unit. The IR spectra of the obtained FA sample contain a wide passband with a frequency of 3453 cm-1, which corresponds to vibrations of aliphatic groups, as well as stretching vibrations of hydroxyl groups. The transmission maximum with a frequency of 1634 cm-1 may reflect the stretching vibrations of the conjugated carbon - carbon and carbon - oxygen bonds of the carboxylate type.The molecular weight distribution revealed two fractions in the group of fulvic acids. The established adsorption characteristics show the high adsorption ability of FA of peloids. The proposed method helps to obtain a low-ash preparation with preservation of all structural components of the natural substance. The obtained characteristics of FA of peloids allow identification of natural substances; it contributes to the formation of the data and analytical base, which is necessary to shift fulvic acids to the category of standardized pharmaceutical preparations.

humic substances, fulvic acid, fraction, composition and properties