STUDYING THE COMPLEXATION OF V(V) WITH 3-[2-HYDROXY-3- SULFO-5-NITROPHENYLAZO]-PENTADIONE-2,4 IN THE PRESENCE OF A THIRD COMPONENT

Abstract

In the present study, we investigated the formation of the complex vanadium c 3-[2-hydroxy-3- sulfo-5-nitrophenylazo]-pentadione-2,4 (R) in the presence of cationic surfactants (CPAS) including cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTMABr). The study on the pH dependence of complexation revealed that the release of the VR complex occurred at pH=4 with a maximum absorption at λ=425 nm, while the reagent exhibited a maximum absorption at 383 nm. In the presence of the third component, three-component compounds VR-СPBr, VR-CPBr, and VR-CTMABr were formed. The absorption maxima of the mixed-ligand complexes V(V) were bathochromic relative to the absorption maxima of the binary complex, with λmax values of 437 nm, 449 nm, and 454 nm, respectively. The optimal pH for complexation was found to be in the acidic region at pH 4.0, 3.0, and 3.0, respectively. The impact of the third component and reagent concentrations on complex formation was also investigated, with the maximum yield of VR complex was achieved at a concentration of 8·10-5 M R, VR-CPCl at 8·10-5 M R and 8•10-4 M CPCl, VR-CPBr at 8•10-5 M R and 8•10-4 M CPBr, and VR-CTMABr at 8•10-5 M R and 8•10-4 M CTMABr. The optimal ratio of reacting components was determined to be 1:2 and 1:2:2, respectively. The compliance with Beer's law was confirmed, and molar absorption coefficients were calculated from saturation curves. The developed method was applied to the determination of vanadium (V) in the waters of the Akstafa rivers in the Kazakh region of the Azerbaijan Republic. Keywords: complexation of vanadium(V), cationic surfactants, cetylpyridinium chloride, cetylpyridinium bromide, cetyltrimethylammonium bromide.