Salt induced polystyrene latex flocs investigated by neutron scattering

Habauka M Kwaambwa; Maja S Hellsing; Matthew J Wasbrough; Markus Bleuel; Adrian R Rennie

doi:10.1016/j.jcis.2017.05.047

Salt induced polystyrene latex flocs investigated by neutron scattering

J Colloid Interface Sci. 2017 Nov 1:505:9-13. doi: 10.1016/j.jcis.2017.05.047. Epub 2017 May 17.

Authors

Habauka M Kwaambwa¹, Maja S Hellsing², Matthew J Wasbrough³, Markus Bleuel⁴, Adrian R Rennie⁵

Affiliations

¹ Namibia University of Science and Technology, Faculty of Health and Applied Sciences, Private Bag 13388, 13 Storch Street, Windhoek, Namibia. Electronic address: hkwaambwa@nust.na.
² Materials Physics, Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
³ National Institute of Standards and Technology (NIST) Centre for Neutron Research, 100 Bureau Drive, Stop 6102, Gaithersburg, MD 20899-6102, USA; University of Delaware, Chemical and Biomolecular Engineering, 150 Academy Street, Newark, DE 19716, USA.
⁴ National Institute of Standards and Technology (NIST) Centre for Neutron Research, 100 Bureau Drive, Stop 6102, Gaithersburg, MD 20899-6102, USA.
⁵ Materials Physics, Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, 751 20 Uppsala, Sweden. Electronic address: Adrian.Rennie@physics.uu.se.

PMID: 28554043
DOI: 10.1016/j.jcis.2017.05.047

Abstract

Studies with a model system consisting of polystyrene latex particles showed that the protein from seeds of Moringa trees adsorbs to the surface and causes flocculation as unusually dense aggregates. In this study, electrolytes sodium chloride (NaCl), ferric chloride (FeCl₃) and aluminium sulfate (Al₂(SO₄)₃) have been used to aggregate model polystyrene particles. The study augments previous work using neutron scattering on the flocculation of polystyrene latex with protein from seeds of Moringa trees that had indicated higher floc dimension, d_f, values as the concentration of particles increased. The measurements were made using ultra small-angle neutron scattering. Generally the fractal dimension, and thus the floc density, increased with particle concentration and salt concentration. Flocculation was apparent at much lower concentrations of FeCl₃ and Al₂(SO₄)₃ than of NaCl. The values of d_f were found not to simply scale with ionic strength for the three electrolytes studied with FeCl₃ being the most effective flocculating agent.

Keywords: Aluminium sulfate; Critical coagulation concentration; Ferric chloride; Floc dimension; Flocs; Polystyrene latex; Ultra small-angle neutron scattering.