Abstract:

In order to explore the optimum preparation conditions, effects of FeCl₃ dosage, hydrolysis temperature and dialysis time on the particle size, conductivity, pH and double layer potential (ζ) of Fe(OH)₃ sol were systematically studied. The ultraviolet-visible reflection spectrophotometry was used to track the particle size of Fe(OH)₃ sol. With the increase of FeCl₃ dosage, the particle size of the colloid increased, the reflectivity decreased and the reflection wavelength shifted to longer wavelength, which is in accordance with the quantum confinement effect theory. The excessive Cl^- would inhibit the conductivity, and the stability of Fe(OH)₃ sol with larger particle size would be worse. Because of the better synergistic effect of q/m and V/l under the action of electric field of 80 V with electrophoresis, the ζ of the Fe(OH)₃ sol prepared under the optimum conditions (c_FeCl3, 0.01 mol·L^-1; 100℃; dialysis time, 1 d) was 43.67 mV which was most close to the theoretical value of 44.00 mV.

Key words: Fe(OH)₃ sol, Dialysis, Electrophoresis, Particle size of Sol, Reflectivity