Comparison of EW

When NaCl is added into the cell which is non-membrane with two electrodes, Chlorine is produced in the anode, Sodium hydroxide is produced in the cathode and these reactants react chemically in solution to produce NaOCl, a powerful oxidant. The NaOCl produced in this manner will be affected according to pH as follows.

- NaOCl + H2O → HOCl + Na+ OH- [Low pH]

- HOCl → H+ OCl- [High pH]

The concentration ratio of HOCl and OCl- depends on the concentration of hydrogen ion (pH), and the concentration of HOCl increases as the pH decreases. Conversely, the concentration of OCl- increases as the pH increases.

In general, HOCl represents approximately 80 times stronger oxidation than OCl-, so the higher the form of HOCl, the higher the treatment efficiency is expected. Figure 1 shows the fraction of HOCl and OCl- according to pH.

If the ratio of OCl- increases, which means the form of NaOCl will be increased.