THE EFFECT OF AMINO ACIDS ON THE STABILITY OF IRON(III) HYDROXIDE SOLS

ABSTRACT

The dispersion and coagulation phenomena of iron(III) hydroxide sols were investigated in the presence of amino acids. The amino acids used were L-alanine, L-glutamic acid and L-arginine. The iron(III) hydroxide sols were prepared by pouring an aqueous iron(III) chloride solution into boiling distilled water. By adding sodium hydroxide solution into the sol which contained amino acid, the changes in turbidity of the sol, τΔ, were measured using a spectrophotometer and an automatic recording system. The zeta potentials of sol particles were measured by ultra-microelectrophoresis. It was found from the results thus obtained that the pH value which brought the maximum value of Ax nearly coincided with the isoelectric point of the sol particles, and the most effective concentrations of amino acids to stabilize the sols were about 10^-3 10^-4 and 10^-5 mol-dm^-3 for L-alanine, L-glutamic acid and L-arginine, respectively.