Kinetics of the preparation of insoluble hexacyanoferrate(II) compounds measured by potentiometry coupled with radiochemistry

Abstract

The preparation of insoluble hexacyanoferrates(II) by a new process involving slow growth on sodium hexacyanoferrate(II) crystals in concentrated zinc or nickel solution was studied. The growth kinetics were deduced from the passage of sodium into the solution using a sodium-selective electrode coupled to a desk computer. Systematic errors were corrected using ²⁴Na-labelled sodium hexacyanoferrate(II) crystals. The influence of temperature, composition and concentration of the solution on the kinetics was measured. The results can be explained by an osmotic phenomenon. Experimental curves were compared with several mathematical models.