Yh. Hu et al., ELECTROKINETIC BEHAVIOR OF SELECTED ALKALI AND ALKALINE-EARTH FLUORIDE SALTS IN ORGANIC-SOLVENTS, Colloids and surfaces. A, Physicochemical and engineering aspects, 141(2), 1998, pp. 193-203
Electrophoretic mobility measurements by laser-Doppler electrophoresis
are reported for selected alkali and alkaline-earth fluorides in diff
erent organic solvents. These measurements coupled with FTIR/transmiss
ion spectroscopy (FTIR/TS) studies allow for the sign of the surface c
harge to be predicted for fluoride salts in organic solvents. On the b
asis of this analysis, the electrokinetic behavior in both hydrogen an
d non-hydrogen bonding liquids can now be explained. Analysis of these
results show that the surface charge of fluorides in methanol (hydrog
en bonding liquid) is positive as it is in water. Importantly, the sur
face charge of fluoride salts in other organic solvents (nonhydrogen b
onding liquids) can be either positive or negative depending on the na
ture of the organic solvent. For example fluoride salts are negatively
charged in acetone due to the strong solvation of the cation relative
to the fluoride ion. The opposite is true for water and other protic
solvents where the fluoride ion is more extensively solvated. (C) 1998
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