Low-cost materials containing carboxyl groups have been synthesized by grafting succinic anhydride onto sawdust and cotton fibers. These materials were used after activation with NaHCO3 for the removal of Cu2+ from water. Removal of copper was carried out at different concentrations in a discontinuous reactor and in a continuous adsorption column. The adsorption of Cu2+ obeys to the Langmuir isotherm law and the values determined for the separation factor show that the system adsorbent/adsorbed substance is favorable to the adsorption process. Copper desorption and adsorbent regeneration can be achieved with diluted acid.

Removal of Cu2+ from Aqueous Solutions by Adsorption on Chemically Modified Cellulosic Supports

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

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

Real public health problem, cancer is one of the pathologies that mobilize the entire scientific community. The conception of effective drugs against this pathology has become a challenge for all actors in research.
Some molecules such as makaluvamines have shown important anticancer properties. These molecules belong to the family of alkaloids generally active in charged forms. The purpose of our work is to determine the protonation or methylation sites, relative stability and reactivity potential of some makaluvamines by a quantum chemistry method.
B3LYP/6-311++G(d,p) theory level is used for all the calculations done. Firstly, we have estimated the gas phase basicity (GB) and proton affinity (PA) for the different heteroatoms of the molecules. Secondly, electronic energies, enthalpies of formation and free enthalpies of formation calculation permitted us to deduce the relative stability of the different forms of studied makaluvamines. Thirdly, Fukui functions, chemical softness and hardness, chemical potential and electrophilia index calculation lead us to the analysis of the reactivity.
The results obtained permit us to identify the preferred site of protonation / methylation, to show that the charged forms are more stable and more reactive than the neutral forms.

http://www.issr-journals.org/links/papers.php?journal=ijias&application=pdf&article=IJIAS-18-239-07

Determination of protonation and methylation sites of neutral makaluvamines, relative stability and reactivity potential of the charged forms

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

L'etude experimentale de la deprotonation de l'uracile et ses homologues a ete completee par la caracterisation des differents coordinats a l'aide d'un calcul quantique base sur une methode semi-empirique Austin Model 1(AM1). Cet examen concerne le calcul des charges atomiques nettes, des moments dipolaires, des potentiels d'ionisation et des affinites protoniques. Nous avons constate que l'ordre d'acidite en solution aqueuse est bien correle avec les charges atomiques des hydrogenes labiles calculees a l'etat isole. Par contre, les affinites protoniques, tres affectees par le phenomene de solvatation qui permet une meilleure stabilisation des molecules, donnent un ordre different.

Protonation of uracil, thymin and 5-halogenouracil examined at the isolated state. calculation of the protonic affinitys by the ami method

La modification chimique des celluloses naturelles par des fonctions carboxylique, amide, amine, ester....leurs conferes des caracteristiques specifiques pour la retention d'ions metalliques toxiques presentsdans les effluents. Les differentes etapes de cette modification consistent en la preparation de l'echantillon puis aux greffages des fonctions. Plusieurs parametres peuvent influer sur le greffage tels que la temperature, le temps, la quantite de reactifs, le catalyseur,.... Une etude complete sur le coton, pris comme support modele, est realisee. Le greffage de l'anhydride succinique et la methode d'extraction du cuivre (II) sont optimises dans le but d'une utilisation a l'echelle industrielle. On note que l'extraction depend de la concentration initiale en Cu 2 + de la solution etudiee, du temps de contact et du pH. A pH basique, le rendement d'extraction du cuivre atteint les 100%. La desorption du cuivre est possible sous l'action d'acide nitrique ce qui autorise le recyclage du support obtenu. L'analyse spectroscopique IR confirme la complexation et la decomplexation de Cu 2 + .

Elaboration of grafted celluloses as ion exchangers from natural materials. application to the metallic extraction

Les constantes de stabilite protonique d'acides chlorophenoxyacetique et chlorophenoxypropionique: 2,4-D, 2,4-MCPA, 2,4,5-T, 2,4-DP et 2,4-MCPP, qui sont des pesticides, ont ete determinees a 25°C et a force ionique μ = 0,1 (NaNO 3 0,1 M) par des mesures potentiometriques. Cette etude a mis en evidence un seul equilibre de dissociation correspondant a la fonction carboxylique. L'examen spectrophotometrique, dans le domaine de l'ultraviolet a permis de confirmer les resultats obtenus par potentiometrie. Les donnees optiques ont ete utilisees pour la determination des facteurs intensifs spectrophotometriques des differentes formes protonees. Enfin, un ordre decroissant d'acidite suivant a ete etabli: 2,4-D> 2,4-MCPA > 2,4-DP > 2,4, 5-T> 2,4-MCPP. Cet ordre est en bonne concordance avec les resultats theoriques determines par la methode AMI a l'etat isole.

H. Eljazouli

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

Protonation of uracil, thymin and 5-halogenouracil examined at the isolated state. calculation of the protonic affinitys by the ami method

Elaboration of grafted celluloses as ion exchangers from natural materials. application to the metallic extraction

Study of the protonic dissociation of chlorophenoxyacetic and cholorophenoxypropionic acids by potentiometry and UV-visible spectroscopy