title: Kinetic and thermodynamic uranyl (II) adsorption process into modified Na-Magadiite and Na-Kanemite.
abstract: The compound 2-mercaptopyrimidine (MPY) was attached onto synthetic Na-Magadiite (M) and Na-Kanemite (K) samples by homogeneous route. The final matrices named M(MPY) and K(MPY) have been characterized through X-ray powder diffraction and scanning electron microscopy (SEM). The resulted materials were submitted to process of adsorption with uranyl solution at pH 2.0 and 298+/-1K. The kinetic parameters were analyzed by the Lagergren and Elovich models of adsorption and demonstrated to be good fit for all experiments. From calorimetric determinations the quantitative thermal effects for uranyl(II)/basic center interactions gave exothermic enthalpy, negative Gibbs free energy, and positive entropy. These thermodynamic data confirmed the energetically favorable condition of such interactions at the solid/liquid interface for all systems.
authors.affiliation: Instituto de Química, Universidade Estadual de Campinas-UNICAMP, Caixa Postal 6154, 13084-971 Campinas, São Paulo, Brazil. dlguerra@iqm.unicamp.br
authors.forename: Denis Lima
authors.initials: DL
authors.lastname: Guerra
authors.forename: Alane Azevedo
authors.initials: AA
authors.lastname: Pinto
authors.forename: Janaína Azevedo
authors.initials: JA
authors.lastname: de Souza
authors.forename: Claudio
authors.initials: C
authors.lastname: Airoldi
authors.forename: Rúbia Ribeiro
authors.initials: RR
authors.lastname: Viana
mesh_terms: D000327:Adsorption; D002151:Calorimetry; D015386:Hazardous Substances / Q000302:isolation & purification; D007700:Kinetics; D017646:Organosilicon Compounds / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics; D014501:Uranium / Q000302:isolation & purification*; D014875:Water Pollutants, Radioactive / Q000302:isolation & purification*
chemical_list: D015386:Hazardous Substances; C542339:Na-kanemite; C542338:Na-magadiite; D017646:Organosilicon Compounds; D011743:Pyrimidines; D017640:Silicates; D012996:Solutions; D014875:Water Pollutants, Radioactive; C064001:pyrimidine-2-thiol; D014501:Uranium