Effect of C3, C4 and C5 alcohols and water on the stability of dispersions with alumina and aluminum hydroxide

Abstract

Non-aqueous alumina and aluminum hydroxide suspensions in n- and iso-C₃, C₄ and C₅ alcohols were prepared. The stability of these suspensions with and without the addition of water was established from the minimum times to settle. There is a correlation between the zeta and net repulsive electrostatic potentials with suspension stability. Also in anhydrous media the aluminum hydroxide suspensions are more stable than the alumina suspensions and with the addition of water the stability of the aluminum hydroxide suspensions increases, whereas that of the alumina suspensions decreases. In the latter, after a monolayer of water is adsorbed on the particles, they reverse their negative into positive charges. This is accompanied by a fairly sharp decrease in the stability of the suspensions.