Abstract:

In order to solve time-consuming problems during purification of coarse Fe(OH)₃ colloid, two novel methods were proposed, that is, hot-cold alternating dialysis and mixed ion exchange resin. We investigated the optimum purification condition of the two methods. In addition, advantages and disadvantages were discussed in details. The results indicated that colloid conductivity could decrease to 560 μS·cm^-1 when dealing with colloid in 60℃ hot water for 35 min and subsequently in cold water for 15 min. While using mixed anion and cation ion exchange resin, colloid conductivity could go down to 42 μS·cm^-1 when the mass ratio of the anion and cation ion exchange resin is 1:1 (total amount of resin is 10 g) and when the colloid volume is 45 mL. Due to the fact that either method has their strengths as well as weaknesses, we select feasible one depending on specific teaching circumstances.

Key words: Colloid, Dialysis, Ion-exchange resin, Conductivity