Stabilität und Koagulation natürlicher und künstlicher kolloidaler Suspensionen

In the considered thesis colloidal particles on polystyrene base, synthesized by the way of emulgator-free copolymerization has been matter of investigation. The surfaces of these particles possess amphoteric groups causing a positive or negative charge depending on the pH of the medium. Considering their isoelectric point the particles show reversible coagulation. These charged colloidal particles perform electrophoretic motion when an electric field is applied to the cell containing the dispersion. In combination of electrophoretic measurements with the well known method of laser-doppler-anemometrie it is possible to get information about the electrophoretic mobility of these particles and so one can draw conclusions about the quantity of effective surface charge. In this paper the electrophoretic mobility as an indicator for surface charge were measured under different conditions. Changing the pH, the kind of electrolyte and its ionic strength and the hydrophobicity of the medium demonstrates the strong influence of these parameters. As a result one can see that even in very low concentrations of the electrolytic systems, i.e. 5*10-7 mol/l, the mobility shows a characteristical behaviour under the examined conditions. Further on it is possible to study the behaviour of stability of the dispersion under these conditions. Furthermore adsorption experiments with the spherical protein bsa on the particle surface were made even under different conditions. It seems obviously clear, that bsa adsorbs more effective on hydrophobized particle surfaces. Compared to these model systems colloidal particles from water and waste water were examined. Neither their real configuration nor their matter is known, but only by knowledge about their electrophoretic behaviour it is possible to draw conclusions about their stability. Using salts on the base of iron and chlorine to separate these particles from the medium it is possible to optimize the required dose. It is a very interesting result that a quick measurement of these physicochemical parameter offers a reliable method in the treatment of water and waste water.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2001

Author dc:creator

• Kuck-Meens, Christa

Contributors dc:contributor

• Versmold, Heinrich

• info:eu-repo/classification/ddc/540
• Chemie
• Kolloides System
• Ampholyte
• Koagulation
• Stabilität
• Elektrophorese

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-118941%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A56860