Adsorption of thiourea and its methyl derivatives from chlorate(VII) with varied water activity

Abstract

The comparison of thiourea, methylthiourea, dimethylthiourea and tetramethylthiourea adsorption at mercury|sodium chlorate(VII) interface was done. For the sake of due to the specific interactions between sulfur and mercury all the compounds examined are pointed with their negative end towards mercury, even at the negative values of an electrode charge. However the change of an electrode charge is connected with the change of an adsorbate reorientation. It was found that with the increase of the methyl group amount in a molecule of thiourea methyl derivatives: (i) the range of adsorption potentials is expanded, (ii) the values of zero charge potentials and surface tension decrease, (iii) the surface excesses increase. Whereas the considerable changes of adsorption energy values were not fund. The lack of symmetry results in a molecule, while the methylthiourea interaction constants are much more higher than the interaction constants of the other compounds examined. The changes of adsorption parameters as a function of the supporting electrolyte concentration are analogous for all the adsorbates examined. They point to the competitive adsorption of thiourea methyl derivatives and ClO4–.