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Title: The Sedimentation of Suspensions of Charged Spherical Particles in Electrolytes.
Author: Ipekoglu, U. A.
ISNI:       0000 0001 3586 8967
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 1977
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In part one of this thesis a review and discussion of the literature relating to sedimentation, electrical double layer and electrokinetic phenomena occurring as a result of the existence of double layer are presented. Particular attention is given to work on the sedimentation velocity of suspensions of charged particles settling in an ionic medium and the effect of double layer on sedimentation velocity. In part two, apparatus specially designed for this investigation and experimental procedure are described. The fluidisation technique, chosen for the measurement of sedimentation v.elocities of model suspensions of closely sized (aprox. 10-18, 20-28, 28-lJ:0,38-53, 53-63 microns) spherical glass particles in inorganic electrolytes is outlined. The sedimentati6n velocities of suspensions, determined at various solids concentrations of the fluidised bed and at a number of electrolyte concentrations of the aqueous fluidisation medium, are given. It wa s found that the ionic nature of the fluidisation medium affects the sedimentation velocity of suspensions of uniform glass spheres. Significant reductions in sedimentation velocity were observed in the aqueous solutions of sodium hydroxide and hydrochloric acid used in the experiments. The empirical expression u = (0.00562-0.000268 pH) d(o.OOllpIf+ 2.074) (1 )(2.50+0.lJ:2pH + c -c 0.5l6d derived from test results, gives the sedimentation velocity of suspensions of spherical glass particles as a function of particle diameter, d, solids volume fraction, c, and the pH of sedimentation medium. The experimental work and the empirical equation for sedimentation velocity are confined to the laminar flow region. The above relationship is empirically verified within the • particle size range of 10 to 65 microns for solids volume fractions below 0.50 and within the pH range of 2.5 to 12. Electro-kinetic measurements were carried out to relate the pH of the sedimentation medium to zeta potential of soda glass particles,,. • The relationship can be 'expressed in the form of: pH = 1.69 + 0.13> The above equation was found from the results of electrophoresis and streaming potential experiments and is valid for soda-glass particles in the pH range 2.0 ( pH < 12.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available