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1
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Catalytic activity of thiourea and its selected derivatives on electroreduction of In(III) in chlorates(VII)

100%
Nosal-Wiercińska A.
Open Chemistry
|
2010
|
vol. 8
|
issue 1
1-11
EN
It was found that thiourea, N-methylthiourea, N,N′-dimethylthiourea and N-allylthiourea accelerate the electroreduction process of In(III) ions in chlorates(VII). These substances are adsorbed on mercury from chlorates(VII). The relative surface excesses of thiourea and its derivatives increase with the increase of their concentrations and electrode charge. After adding thiourea, N-methylthiourea, N,N′-dimethylthiourea and N-allylthiourea to the solution an acceleration of the electroreduction process of In(III) ions occurs. This process depends on two factors: the adsorption of an accelerating substance on mercury and on the formation of complexes between a depolarizer and an accelerating substance on the electrode surface. The equilibrium of this complexing reaction determines the magnitude of the catalytic effect. [...]
2
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Adsorption of cystine at mercury/ aqueous solution of chlorate (VII) interface in solutions of different water activity

100%
Nosal-Wiercińska A.
Open Chemistry
|
2012
|
vol. 10
|
issue 4
1290-1300
EN
[...]
3
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Influence of temperature on the reduction kinetics of Bi(III) ion in the presence of cystine in chlorate (VII) solutions of decreased water activity

100%
Nosal-Wiercińska A.
Open Chemistry
|
2014
|
vol. 12
|
issue 2
213-219
EN
The results of the kinetic measurements of Bi(III) electroreduction on a mercury electrode in 1–8 mol dm−3 chlorate (VII) solutions and in the presence of cystine demonstrate a dependence of the process on the temperature. The applied electrochemical techniques (DC polarography, cyclic and SWV voltammetry) allowed for the determination of the kinetic and thermodynamic parameters and their correlation with water activity. The catalytic activity of cystine was confirmed by the decrease in overall enthalpies of activation. The changes in the values of ΔH ≠ and ΔS 0 for Bi(III) electroreduction in the presence of cystine with the increase of chlorate (VII) concentration showed that the mechanism is different in solutions with low water activity as compared to those with high water activity. Probably it is connected with a different structure of the activated complexes (Bi-Hg(SR)2), mediating electron transfer.
4
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Comparison of stability properties of poly(acrylic acid) adsorbed on the surface of silica, alumina and mixed silica-alumina nanoparticles - application of turbidimetry method

45%
Wiśniewska M., Urban T., Nosal-Wiercińska A., Zarko V., Gun’ko V.
Open Chemistry
|
2014
|
vol. 12
|
issue 4
476-479
EN
The influence of anionic poly(acrylic acid) - PAA addition on the stability of synthesized silica, alumina and mixed silica-alumina suspensions as a function of solution pH was studied. The turbidimetry method was used to monitor the changes of the examined systems stability over time. The calculated stability coefficients enabled estimation of polymer adsorption influence on stability of metal oxide suspension. It was shown that the alumina suspension without the polymer is the most unstable at the pH values 6 and 9, whereas the silica polymer was most unstable at pH 3. PAA with higher molecular weight (240 000) is a relatively effective stabilizer of all investigated adsorbents (except silica at pH 3). These properties of poly(acrylic acid) are highly desirable in many branches of industry (e.g. production of cosmetics, pharmaceuticals, paints) where polymers are widely used as effective stabilizers of colloidal suspensions.
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