ELECTROKINETIC PROPERTIES OF POROUS GLASSES IN THE SOLUTIONS OF SPECIFICALLY SORBED IONS OF COMMON ELECTROLYTES

The methods of streaming potential and ultramicroelectrophoresis were applied to study the dependences of the electrokinetic potential of po rous glasses with the pore size 1.3-160 nm on pH and composition of th e background electrolyte (NaCl, CsCl, and LaCl3). The values of zeta-p otential determined by various methods are in good agreement with each other. Dependences zeta-pH typical of indifferent electrolytes are ob served for 10(-3)-10(-1) M NaCl solutions, and pH(IEP) (1.1) is indepe ndent of the pore size. Marked specificity of Cs+ ions is discovered a t concentration 0.1 g-ion/l, which leads to a shift of pH(IEP) to 5.1 for PG-160; hence, the adsorption potential of Cs+ ions could be calcu lated. It was shown that the sign of zeta-potential is reversed in LaC l3 solutions (10(-3)-10(-1) g-equiv/l) at pH > 6.3. The pattern of zet a-pH curves for LaCl3 solutions is determined by hydrolysis (occurring up to the phase formation of positively charged lanthanum hydroxide), adsorption, and heterocoagulation.