parallel capillary in solutions of chlorides containing singly-(H+, Na+, Cs+), doubly-(Ba2+), and triply-(La3+)
charged counterions—in wide ranges of pH and concentrations. It was discovered that the isoelectric point
(IEP) of the investigated silicon oxide coincides with that usually reported in literature and corresponds to pH2
in the absence of specific adsorption. The
–pH dependences for 1 : 1 and 2 : 1 electrolytes are linear in the first approximation (up to pH 6); their slopes decrease with an increase in concentration of the electrolyte and coun
terion charge in accordance with theoretical concepts. The specific adsorption of cesium ions was discovered,
which lead to a shift in IEP to pH 3.3 in the presence of 0.1 M CsCl solution. The specific adsorption of lantha
num ions increases with the surface charge, thus resulting in the appearance of the positive range of electroki
netic potential at pH > 3.3 in the presence of 0.1 g-equiv/l LaCl3 solution. It was established that the specific surface
conductivity on the SiO2 surface is observed only in dilute solutions (c
10
4 M) and equals about 10
8 
–1. A comparison of the values of KS with those calculated by Bikerman’s equation (at
1 = ) indicates that the experimental values exceed the calculated ones by more than an order of magnitude. The results of the electrokinetic
measurements were used to calculate the charge of a diffuse layer, the constants of the dissociation of surface
groups, the adsorption potentials of potential-determining and specifically sorbing ions, and the dependences
of the surface potential on pH and the concentration of 1 : 1 electrolyte.