Investigations of chromium(III) oxide removal from the aqueous suspension using the mixed flocculant composed of anionic and cationic polyacrylamides

Małgorzata Wiśniewska; Stanisław Chibowski; Teresa Urban; Konrad Terpiłowski

doi:10.1016/j.jhazmat.2019.01.068

Investigations of chromium(III) oxide removal from the aqueous suspension using the mixed flocculant composed of anionic and cationic polyacrylamides

J Hazard Mater. 2019 Apr 15:368:378-385. doi: 10.1016/j.jhazmat.2019.01.068. Epub 2019 Jan 22.

Authors

Małgorzata Wiśniewska¹, Stanisław Chibowski², Teresa Urban², Konrad Terpiłowski³

Affiliations

¹ Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland. Electronic address: wisniewska@hektor.umcs.lublin.pl.
² Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland.
³ Department of Interfacial Phenomena, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland.

PMID: 30690390
DOI: 10.1016/j.jhazmat.2019.01.068

Abstract

The main purpose of experiments was determination of the adsorption mechanism of two forms of ionic polyacrylamide (PAM) on the surface of chromium(III) oxide dispersed in the aqueous medium. This was performed in relation to anionic polyacrylamide (AN PAM) and cationic one (CT PAM) in the simple systems (containing only one selected polymer) and in the mixed systems (containing both ionic forms of PAM). The turbidimetry was applied to determine the stability of examined suspensions. To explain the obtained changes in suspension stability after the polymer addition, polyacrylamide adsorbed amount, surface charge density and zeta potential of solid particles were determined. It was found that the solution pH, order of both adsorbates addition as well as the time interval between the AN and CT PAM addition have considerable influence on the structure of polymeric adsorption layer formed on the Cr₂O₃ surface. It was also proved that changes in the PAM adsorbed amount in the systems containing mixed adsorbates result from formation of AN PAM - CT PAM complexes. They are bounded at the interface in the formed multilayer. As a result, the dual-polymer flocculation occurs more effectively than the destabilization process in the suspensions containing only one type of adsorbate.

Keywords: Chromium(III) oxide removal; Dual-polymer flocculation; Ionic polyacrylamide; Mixed adsorption layer; Suspension stability.