Colloido-chemical characteristics of nanoporous glasses with different compositions in solutions of simple and organic electrolytes. 2. Equilibrium electrochemical characteristics of membranes

Resumo

The regularities of variations in the electrokinetic potential and surface charge of nanoporous glass membranes with different compositions have been studied as depending on the type of an electrolyte (sodium, potassium, ammonium, tetramethylammonium, and tetraethylammonium chlorides) and the structure of pore space. It has been shown that, in solutions containing specifically sorbed organic counterions, the range of positive values of electrokinetic potential arises due to the superequivalent absorption of counterions in the Stern layer. It has been found that the influence of the specific adsorption of counterions on the electrokinetic potential of porous glasses increases with the amount of secondary silica in the pore space. The effects of the counterion specificity, pore channel sizes, and composition of a porous glass on the value of the surface charge have been analyzed. The absolute value of the surface charge has been shown to significantly increase in the presence of organic counterions in comparison with inorganic ions throughout the examined range of background electrolyte concentrations.