This paper presents a continuation of our research of the water pollution in
Nistru and Prut Rivers with a series of surface-active substances
(surfactants, SASs) for small river sections with a different urban influence.
The influence of the interaction of CaCO3 and SAS with different chain
lengths and cationic and anionic hydrophilic centers has been analyzed.
UV VIS spectra of mixtures of laurylsulfate with cetyltrimethylammonium in
a ratio of 2:1 and 1:1 and separately the cationic SAS, treated by fine
particles of CaCO3, show significant decreasing in the amount of
cetyltrimethylammonium in analyzed solutions and its transfer on the
surface of carbonate calcium nanoparticles. Fixing laurylsulfate on the
surface of CaCO3 particles causes a decrease of the amount of cationic
SAS in analyzed solution. As a result of the cationic and anions SASs
interaction, a combination (or so-called complex) with a chemical
composition [anionic SAS * cationic SAS], electrostatically bonded, is
formed. UV-VIS spectra reveal the decomposition of this complex in
solution in the case of calcium carbonate adding. On the surface of CaCO3
particles, cetyltrimethylammonium can be bonded by laurylsulfate through
hydrophobic chains. Calcium carbonate adding changes the nature of
interaction of laurylsulfate with cetyltrimethylammonium along with the
spatial orientation of molecules on the SAS solid phase surface. This
phenomenon leads to increased degree of toxicity of cationic SAS in
aquatic environment. The obtained results have been confirmed both by
current published papers, as well as laboratory simulations in waters taken
from small rivers (Isnovat, Raut and Bac).