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本帖最后由 breezing 于 2016-10-22 23:39 编辑
你说的加酸是有道理的
找到理论依据了,不能太酸,但是5-7之间消毒效果最好。
pH Effect
When sodium hypochlorite is dissolved in water, the resulting solution is quite basic due to the
production of OH– ions by the following reaction:
NaOCl (s) + H20(l) → HOCl (aq) + NaOH (aq)
The various free chlorine components exist in equilibrium in water; the predominant form depends on
the pH. When the pH is between 2 – 7, the equilibrium favors HOCL. As the pH falls below 2, the main
form is Cl2. At a pH of 7.4, HOCl and OCl–
are about equal, and as the pH goes above 7.4, increasing
proportions of OCl– are present. Maximum disinfecting efficacy is achieved at pH 4-5, because
essentially all the chlorine is present as HOCl which is two orders of magnitude more effective than OCl–
.
Below pH 4, increasing amounts of Cl2 are present which will evolve from solution and be lost to the
system at atmospheric pressure. Chlorine gas is also quite toxic, so pH below 4 should be avoided. On
balance, for safety and efficacy a pH of 5-7 works best; addition of a small amount of HCl to achieve this
pH should be considered when disinfecting materials that may be contaminated with bacterial
endospores or other resistant forms of microorganisms. For most routine disinfection, no adjustment
2
of pH is necessary. Extreme caution should be exercised when acidifying bleach solutions; too much
acid will cause toxic Cl2 to off-gas. |
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