LEADER OF ELECTROLYSIS TECHNOLOGY |
Hypochlorous acid (HClO) is a strong sterilant and stable, while hypochlorite ion (OCl-) has a low sterilization effect and is unstable. Comparing the sterilization power of these two, the bactericidal power of HClO can reach as much as 80 times that of OCl-. (Please refer to the graph following)
Sterilization Efficiency Measurement
Ex. the E. Coli killing time while chlorine is 0.1mg/L
From the graph left, when the chlorine concentration is 0.1ppm, hypochlorous acid kills 99% of the E. Coli in only 1.5 minute, while hypochlorite ion needs 120 minutes.
Source: Techlonogy of Purifiying Water |
The time (in minute) for killing 99% of E. Coli E. Coli (minute) at water temperature 2~6℃
The table below shows the relations among that sodium hypochlorite. its pH value, and the consistence rate of HClO
Concentration of Sodium hypochlorite | pH value of sodium hypochlorite | Consistence rate of Hypochlorous Acid (HOCL) |
---|---|---|
100ppm of Sodium hypochlorite | 8.6 | 6% of HOCl |
4,000ppm of Sodium hypochlorite | 10.2 | 0~0.6% of HOCl |
120,000ppm of Sodium hypochlorite | 11.83 | 0~0.2% of HOCl |
=> while sodium hypochlorite at 4,000ppm (calculate at the optimum level) contains 24ppm of hypochlorous acid (HClO) and 3,976ppm of hypochlorite ion (OCl-)
{ | 24ppm of HClO → points |
3976ppm OCl- → 3976/80=49.7 points |
=> Total sterilization point is 73.7 points
As the hypochlorous acid water consists of 100% HClO, when the hypochlorous acid reaches 80ppm, its sterilization points reaches 80 points.
substance | sterilization point |
---|---|
SuperAqua 80ppm | 80 points |
Sodium Hypochlorite 4,000ppm | 73.7 points |
From the table above, the sterilization efficiency of 4,000ppm sodium hypochlorite is approximate to 80ppm hypochlorous acid.
※ Reference:Tanbo Norihito & Ogasawara Yuichi. Water Purification Technology. Gihodo Shuppan 1985