Competitive Cd2+/H+ Complexation to Polyacrylic Acid Described by the Stepwise and Intrinsic Stability Constants

Autor:	Francesc Mas, Calin David, Jaume Puy, Josep Galceran, José Salvador, Encarnació Companys, Carlos Rey-Castro, Josep Lluís Garcés
Rok vydání:	2008
Předmět:	Denticity Proton Stereochemistry Polyacrylic acid Binding energy Surfaces Coatings and Films Metal chemistry.chemical_compound chemistry Ionic strength visual_art Materials Chemistry visual_art.visual_art_medium Physical chemistry Carboxylate Physical and Theoretical Chemistry Macromolecule
Zdroj:	The Journal of Physical Chemistry B. 112:10092-10100
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp802571f
Popis:	Stepwise constants can be used to describe competitive proton and metal binding to macromolecules with a large number of sites. With the aim of accessing information on the microscopic binding model, we report an expression that connects the stepwise constants to the site-specific metal constants. This expression holds for a very general complexation model including heterogeneity, interactions, and chelate complexation. Assuming bidentate binding of the Cd ions to adjacent carboxylate groups in poly(acrylic acid), stepwise and intrinsic stability constants for proton and cadmium binding were estimated from the experimental data. Intrinsic values were split into specific and electrostatic contributions (by means of the Poisson-Boltzmann equation under cylindrical geometry). Free of the electrostatic contribution, the remaining Cd binding energy showed almost no dependence on the coverage and ionic strength, and the corresponding average values allowed for a reasonable reproduction of raw binding data. Small systematic discrepancies from the homogeneous behavior are critically discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b9352db2f1e97e9bfa81ddd2ec6d03f4 https://doi.org/10.1021/jp802571f Zobrazit plný text záznamu