Appendix В
Appendix B. Methods for zeta potential measurement
B.1. Sample preparation
The aqueous phase used here is synthetic brine with pH 8.3, as introduced in
section 4.2.1. Kaolinite (A∣2Si2O5(OH)4) and alumina (A∣2O3) are obtained from
Sigma-Aldrich with detailed information in section 4.2.1. All the salts in the
synthetic brine were obtained from Fisher Scientific.
All the samples of 50 ml 1.0 % (w∕w) kaolinite or alumina suspension were
prepared in the brine with different additives. Branson Sonic Probe 450 was used
for the sonication of the mixture (probe tip was placed about 1/2" into the solution,
sonication rate at setting 4 for 1 minute). The mixture was left overnight. Before
measurement the mixture was shaken and settled for 30 minutes to allow the
sedimentation of larger particles and get stable suspension. Beckman Coulter
Delsa 440 Doppler electrophoretic light scattering analyzer was used to measure
zeta potential of kaolinite or alumina in the brine.
B.2. Measurement Procedure
Referto Coulter Delsa 440 Product Reference Manual, June 1988.
1. Prepare clay samples as described in section B.1.
2. Turn on the instrument for 1 h for warming up.
3. Perform position calibration of the sample. Inject clay dispersion into sample
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