Stability mechanism of the silica suspension in the Sinorhizobium meliloti 1021 exopolysaccharide presence

• The SiO2-EPS system was examined.
• The EPS adsorption depends on the pH value.
• In the EPS presence the system stability changes slightly.

This paper describes the electrokinetic, adsorption and stability properties of the silica–exopolysaccharide Sinorhizobium meliloti (EPS). Exopolysaccharide adsorbs on the silica surface in the whole pH range, but the adsorption amount increases with the pH growth (at pH 9 approx. 0.8 mg/m2). The EPS adsorption affects the electrokinetic and stability properties of the system. At low pH values (3 and 4.6) the increase in the system stability occurs (electrosteric interactions), whereas at higher (7.6 and 9) the light system destabilization was noted (formation of a single polymer bridges between particles).

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