INFLUENCE OF A KIND OF ELECTROLYTE AND ITS IONIC STRENGTH ON THE ADSORPTION AND ZETA POTENTIAL OF THE SYSTEM: POLYACRYLIC ACID/MnO2/ELECTROLYTE SOLUTION

The influence of a kind of electrolyte (NaCl, KCl, CaCl2 and MgCl2), its ionic strength (0.01; 0.1; 1) and pH of a solution (3; 6; 9) on the adsorption of polyacrylic acid (PAA 2 000 and 60 000) on the surface of manganese dioxide (MnO2) was measured. PAA adsorption was the highest in the presence of calcium chloride. Adsorption of polyacrylic acid increased also with ionic strength but decreased with the increase of pH of the solution. These results are consistent with theoretical findings concern-ing adsorption of anionic polyelectrolytes on surface of metal oxides. The influence of a kind of elec-trolyte and its ionic strength on the zeta potential in the presence of PAA was also measured. It was proved, that the zeta potential of MnO2 is highest in the presence of calcium chloride as a background electrolyte. Moreover the zeta potential increased with ionic strength of all measured systems. key words: polyacrylic acid, manganese dioxide polymer adsorption, polymer conformation, zeta po-tentia