Behaviour of Nitrogen Soluble Forms in Natural Water in the Presence of Anionic and Cationic Surfactants and Mineral Substrates

Abstract

The redox processes, organic substances accumulation, chemical equilibria and adsorption of organic substances on the substrate surface function of natural water compositions and substrate granule sizes have been investigated. Laboratory simulations have been carried out for the Nistru and Isnovat river waters. The natural water models containing laurylsulphate (LS) as anionic surfactant (SAS An) and cetyltrimethylammonium (CTMA) as cationic surfactant (SAS Ct), separately and in a body, as well as the substrates Al(OH)₃, Al₂O₃, CaCO₃, H₂SiO₃, light fraction (clayey) of diatomite and expanded clay powder have been studied. The timely distribution of the soluble nitrogen species containing NH₄⁺, NO₂^- and NO₃^- in the samples of natural waters has been analyzed. It has been found that LS diminishes the redox processes braking due to the partial fixation of toxic organic matter. Similar, but more pronounced enhancement impact on oxidation of nitrite ions as a result of fixation and sedimentation of organic components has been found in the case of the calcium carbonate powder. Also, CaCO₃ produces a better SAS Ct separation/inactivation of organic part in the presence of both anionic and cationic SASs. A water self-purification processes effectiveness in polluted river waters decreases in the CaCO₃, Al(OH)₃, Al₂O₃, H₂SiO₃, light fraction (clayey) of diatomite, expanded clay powder substrate series.