MIGRATION FORMS OF BASIC IONS IN GROUNDWATER OF COAL-BEARING SEDIMENTS OF KUZBASS WITH A FOCUS ON COMPOUNDS WITH HUMIC ACIDS (BY SIMULATION RESULTS)

Abstract

The relevance. When studying the formation of the composition of organic-rich waters, it is necessary to take into account organomineral compounds that shift the equilibria in geochemical processes (dissolution, leaching, precipitation and co-deposition, sorption, ion exchange, oxidation-reduction) towards the aqueous phase, thereby directly affecting the composition of waters. The main aim of the research is to calculate the forms of migration of basic ions and some micro-components, with an emphasis on organomineral complexes, based on available data on the composition of waters, including concentrations of fulvic and humic acids. Objects: groundwater of Permian terrigenous-coal-bearing deposits (Kolchuginskaya formation) Naryksko-Ostashkinskaya areas located at depths of 0,4–1,2 km in the zone of delayed water exchange, as well as overlying fresh underground zones of active water exchange, river and lake waters. Methods. The chemical and organic composition of water was determined by standard methods in the Problem Research Laboratory of Hydrogeochemistry of Tomsk Polytechnic University, the determination of fulvic acids (FA) and humic acids (GA) was carried out by titration based on bichromate consumed for carbon oxidation of fulvohumic acids. The forms of humic acid migration were calculated using the HydroGeo software package. Results. The migration forms of the main ions and, for the first time, humic acids contained in high concentrations in the natural waters of the Naryk-Ostashkin territory (Kuzbass) were determined by thermodynamic calculations. It was established that cations migrate in a simple ionic form, but in the zone of delayed water exchange at high concentrations of bicarbonate ion (soda water), a significant part (up to 50 %) begins to take their carbonate forms. Only iron forms compounds with fulvic acids in significant amounts (more than 1 %), but under specific geochemical conditions. Humic acids themselves, relative to their content in waters in % proportion, bind well into complex compounds. Fulvic acids are almost completely consumed, giving preference to Na, even in calcium waters. However, this has little effect on the general substance of Na itself. Humic acids mainly migrate with Mg and Ca, but the more soda composition of the waters, the more their amount remains in free form.

Keywords

• forms of migration
• computational research methods
• basic ions
• organomineral complexes
• fulvic and humic acids
• groundwater
• coal-bearing deposits
• kuznetsk basin