Comparison of EW
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.