L'etude experimentale de l'inhibition de la corrosion du cuivre dans le milieu nitrique par des acides amines tels que l'arginine (Arg), la cysteine (Cys), la glycine (Gly), la lysine (Lys) et la valine (Val) a ete completee par une approche theorique des equilibres de dissociation protoniques de ces acides amines a l'aide d'une methode semi- empirique: Austin Model one (AMl). Le site le plus favorable a la protonation de ces composes est l'atome d'azote du groupement amine. Une correlation lineaire entre l'efficacite inhibitrice obtenue experimentale-ment et la difference d'energie ΔE entre les orbitales moleculaires frontieres a savoir la plus haute occupee (EHOMO) et le plus basse vacante (ELUMO) a ete determinee. Cet examen a permis de constater que la cysteine est le meilleur inhibiteur de la serie des acides amines testes. En outre, le calcul des affinites protoniques et les charges atomiques nettes de la cysteine permet de mettre en evidence les groupements fonctionnels de la Cysteine (NH3+, SH, COOH) qui participent aux phenomenes de complexation Cu (II)/Cys a la surface du cuivre.

Etude théorique de l´effet inhibiteur de certains acides aminés sur la corrosion du cuivre en milieu nitrique

Influence of Metalaxyl and CGA 62828 Adsorption on the Leaching Behavior of Metal‐Contaminated Soils

The study of the ternary interactions of some phenoxyacetic acids derived from a herbicide, with the heavy metals present in soil in trace amounts has been realized by potentiometric measurements. The stability constants of the ternary complexes have been calculated at 25°C and ionic strength 0.1(NaNO3). The experimental results have confirmed the presence of one ternary hydroxide species MH−1(2,4-D)(2,4-MCPA) for Cu(II), Pb(II) and Zn(II) on one hand and MH−2(2,4-D)(2,4-MCPA) for Hg(II) on the other. The order of stability constants has been found to be: Cu(II)>Hg(II)>Pb(N)>Zn(N)>Cd(N). Finally, a quantum approach has been achieved by the semi-empirical AM1 method for the mercuric complex.

Potentiometric examination of ternary complexes of 2,4-D and 2,4-MCPA, components of a weedkiller, with Cu2+, Cd2+, Hg2+, Pb2+ and Zn2+, and a quantum approach to their structures

A. Assabbane

Papers

Potentiometric examination of ternary complexes of 2,4-D and 2,4-MCPA, components of a weedkiller, with Cu2+, Cd2+, Hg2+, Pb2+ and Zn2+, and a quantum approach to their structures