Effect of solution pH on the stability of mixed silica -alumina suspension in the presence of polyacrylic acid (PAA) with different molecular weights

Małgorzata Wiśniewska, Konrad Terpiłowski, Stanisław Chibowski, Teresa Urban, Vladimir I. Zarko, Vladimir M. Gun'ko
2012 Central European Journal of Chemistry  
© Versita Sp. z o.o. The influence of solution pH (in the range 3-9) on mixed silica-alumina suspension in the absence and presence of polyacrylic acid (PAA) was studied. The composition of the adsorbent was SiO 2 (97%) and Al 2 O 3 (3%). The turbidimetry method was applied to record changes in the stability of the investigated systems as a function of time. It was shown that the suspension without the polymer is less stable at pH 3, whereas at pH 6 and 9, the systems were stable. PAA with
more » ... ular weights 100 000 and 240 000 at pH 3 (improvement of system stability conditions) and PAA 2 000 at pH 6 (deterioration of suspension stability) have a great effect on the silica-alumina suspension stability. The stabilization-flocculation properties of polyacrylic acid are a result of a specific conformation of its chains on the solid surface where it depends on the solution pH and the polymer molecular weight.
doi:10.2478/s11532-012-0136-9 fatcat:xl2acop5a5c4bknoi2tlk5bxu4