Studies on the Behavior of Inorganic Ions Caused by Electrodeposition Process. IV.

The Determination of Zinc in Electrodeposited Film by Atomic Absorption Spectroscopy

Abstract

It was reported in the previous paper that zinc in electrodeposited film can be determined quantitatively by means of atomic absorption spectroscopy. In this experiment, zinc in electrodeposited paint film was analyzed quantitavely by an Atomic Absoption Spectrosmeter to determine the relationship between the concentration of zinc in electrodeposited film and that in the electrodeposion paint. An acrylic resin emulsion and a water soluble alkyd resin solution were used.
It was found that the amount of zinc in electrodeposited film increased linearly with the increase in the concentration in paint and the ratio of them was 1 : 1, indicating that the concentration of zinc in paint does not increase during the continuous electropainting process. It was suggested that the velocity of electrophoresis of zinc is the same as that of the resin and that zinc is strongly bonded to the resin, probably to the carboxyl groups in the resin.
Ion exchange method was tested to remove the zinc in paint, and it was found that the concentration of zinc in paint decreased with the increas in the amount of cation exchange resin added and that zinc was removed completely by the use of enough cation exchange resin. It appears that zine can be removed more easily than amine by the cation exchanze resin.
The chemical structure of zinc present in the elecrodeposition paint was also discussed.