Jo May 19, 2023

The amount of free chlorine generated by disinfection is one of the core parameters that should be monitored for seawater aquariums.

Ko Kye Hak, a researcher at the Faculty of Chemistry, has proposed a novel analytical method by which the amount of free chlorine in ozonized seawater can be determined by the conventional cyclic voltammetry (CV) with a bare platinum disk electrode without developing any new sensing material.

He determined the amounts of both free chlorine and ozone in ozonized seawater samples by spectrophotometry, which showed that most of ozone was converted to free chlorine.

CV experiments with a bare platinum electrode were carried out for the samples and attention was paid to the fact that the peak current of hydrogen oxidation generated by water electrolysis, which was ignored in the previous studies, depends on the amount of free chlorine in the sample.

The CVs exhibited a well–defined oxidation peak for hydrogen molecules and the linear range of free chlorine amounts in the ozonized seawater samples spanned from 0.02 to 0.4 mg•L–1 with a correlation coefficient of 0.998 2(n=5), a detection limit of 1.2×10–2mg•L–1 at 3σ and a high sensitivity of 4 063μA•cm–2•mg–1•L.

The reproducibility of this technique had a relative standard deviation of 4.41%(n=10).

For more information, please refer to his paper “A novel cyclic voltammetric determination of free chlorine generated by ozone disinfection in seawater aquarium” in “Chinese Journal of Analytical Chemistry” (SCI).