title: Impact of polyacrylamide with different contents of carboxyl groups on the chromium (III) oxide adsorption properties in aqueous solution.
abstract: The main goal of experiments was determination of solution pH and contents of anionic groups in polyacrylamide (PAM) macromolecules on the stability mechanism of chromium (III) oxide suspension. The spectrophotometry, potentiometric titration, microelectrophoresis, viscosimetry and turbidimetry were applied. They enabled determination of polymer adsorbed amount, surface and diffusion charges of solid particles with and without PAM, thickness of polymer adsorption layer, macromolecule dimensions in the solution and stability of the Cr2O3 - polymer systems, respectively. It was found that adsorption of anionic PAM decreases and thickness of polymeric adsorption layer increases with the increasing pH. Slightly higher adsorption was obtained for the PAM samples containing a greater number of carboxyl groups. At pH 3 and 9 insignificant deterioration of stability conditions of Cr2O3 particle covered with polyacrylamide was observed (neutralization of solid positive charge by the adsorbed polymeric chains (pH 3) and single polymeric bridges formation (pH 9)). The electrosteric repulsion between the solid particles covered with PAM layers at pH 6, is the main reason for significant improvement of Cr2O3 suspension stability in the polymer presence.
authors.affiliation: Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland. Electronic address: wisniewska@hektor.umcs.lublin.pl.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Wiśniewska
authors.affiliation: Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Chibowski
authors.affiliation: Department of Radiochemistry and Colloid Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland.
authors.forename: Teresa
authors.initials: T
authors.lastname: Urban
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D000838:Anions; D002245:Carbon Dioxide; D017608:Chromium Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D000838:Anions; D002245:Carbon Dioxide; D017608:Chromium Compounds; D014874:Water Pollutants, Chemical; D000099166:Polyacrylamides; C041069:carboxyl radical; C023600:chromic oxide
keywords: Anionic polyacrylamide; Carboxyl groups content; Chromium (III) oxide removal; Polymer adsorption; Suspension stability