Croatica Chemica Acta, Vol. 74 No. 1, 2001.
Izvorni znanstveni članak
Influence of the Mixed Adsorption Layer 1-Butanol/Thiourea on the Two-step Electroreduction of Zinc(II) Ions
Jadwiga Saba
; Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland
Kazimierz Sykut
; Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland
Jolanta Nieszporek
; Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland
Dorota Gugała
; Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland
Sažetak
Influence of a constant 1-butanol (BuOH) concentration and various thiourea (TU) concentrations in the bulk on the two consecutive one-electron transfer steps in the electroreduction of Zn2+ ions at Hg electrode is described. It was found that in the range of Zn2+ ions reduction potentials BuOH has the predominant effect on formation of the adsorption mixed layer. The values determined for the total surface excesses of BuOH and TU in the function of Φr potential are linear and, except for the highest TU concentrations, insignificantly depend on the potential. As it follows from the dependence ktf = f(Φr), in the presence of 0.11 mol dm-3 BuOH even the smallest amounts of TU accelerate Zn2+ ion reduction compared with 1 mol dm-3 NaClO4 solution. However, in a solution containing 0.33 mol dm-3 or 0.55 mol dm-3 BuOH this effect takes places only for cTU ≥ 0.033 mol dm-3. The course of the kts1 = f(Γ) and kts2 = f(Γ) dependence indicates that one kind of active complex is formed on the electrode surface in the 0.11 mol dm-3 BuOH solution but in Solutions of a larger amount of BuOH two kinds of active complexes are formed, differing in the extent of hydration.
The obtained results indicate that the stage of the first electron transfer is less susceptible to inhibition by BuOH than the stage of the second electron transfer.
Ključne riječi
electroreduction of Zn<sup>2+</sup>; mixed adsorption; thiourea; 1-butanol
Hrčak ID:
131773
URI
Datum izdavanja:
1.2.2001.
Posjeta: 613 *