title: Sinorhizobium meliloti1021 Exopolysaccharide as a Flocculant Improving Chromium(III) Oxide Removal from Aqueous Solutions.
abstract: Chromium(III) oxide is an amphoteric, dark green solid. This most stable dye is widely used in construction and ceramic industries as well as in painting. In this study, the attempt is made to determine flocculating properties of exopolysaccharide (EPS) synthesized by the bacteriaSinorhizobium meliloti1021, which would increase the efficiency of chromium(III) oxide removal from sewages and wastewaters. The conditions under which EPS is the most effective destabilizing component of chromium(III) oxide suspension have been determined too. In order to characterize the structure of electric double layer formed at the solid/supporting electrolyte (EPS) solution interface, electrokinetic potential measurements and potentiometric titration were performed. The EPS amount adsorbed on the chromium(III) oxide surface as a solution pH function was also measured. Moreover, the stability of Cr2O3suspension in the absence and presence ofS. meliloti1021 EPS was estimated. The pooled analysis of all obtained results showed that EPS causes chromium(III) oxide suspension destabilization in the whole examined pH range. The largest change in the system stability before and after the polymer addition was observed at pH 9. It is probable that under these conditions bridging flocculation occurs in the examined system.
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: Katarzyna
authors.initials: K
authors.lastname: Szewczuk-Karpisz
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: Małgorzata
authors.initials: M
authors.lastname: Wiśniewska
authors.affiliation: Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Pac
authors.affiliation: Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Choma
authors.affiliation: Department of Genetics and Microbiology, Faculty of Biology and Biotechnology, Maria Curie Sklodowska University, Akademicka 19 Street, 20-033 Lublin, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Komaniecka
keywords: Adsorption; Chromium(III) oxide; Potentiometric titration; Sinorhizobium meliloti 1021 exopolysaccharide; Suspension destabilization; Zeta potential