When a small amount of salt is added to the tap water and electrolyzed through the diaphragm, the water generated at the anode has a quick-acting bactericidal effect,so it has attracted attention.Compared with general disinfectants, they have good performance in terms of biological safety and germicidal efficacy,but are easily affected by ultraviolet rays and organic substances, and sometimes fail to achieve the desired effect.
1.Nature of electrolytic acid water
The method of activating water generally adopts electromagnetic properties, and its activation treatment process includes electric decomposition method, high voltage treatment method, magnetic gas treatment method and other methods.In order to promote the electric decomposition of tap water,a small amount of salt is added, and the acidic water generated at the anode through the diaphragm, especially the electrolytic acidic water as "bactericidal water", has been explained theoretically.This is only one of the so-called "functional water".The correct chemical term should be "electrolytic salt water by anode".Here we call it "electrolytic acid water" for convenience.As one of the indicators of bactericidal performance of electrolytic acid water, the residual chlorine concentration will often be mentioned.In fact, all chlorides such as the last chlorate ion,hypochloric acid and chlorine gas are included.The development concept of electrolytic acid water is that the functional water with high sterilization effect produced by electrolytic tap water is hypochlorite solution.The environment with the redox potential of 1100 mv has greatly exceeded the limit of 900 mv that microorganisms can survive,so microorganisms will die if they cannot survive.In the environment of high redox potential (ORP), the idea under the assumption that microorganisms cannot survive.However, the research results show that although the redox potential is still an indicator value, it does not completely represent everything.
1.Relationship between redox potential, pH value and hypochlorite concentration.As for the redox potential, pH value is an unavoidable problem.Oxidized water is made of tap water as raw material, and there are many kinds of positive and negative ions. The results cannot quantitatively show the relationship with the redox potential, but can qualitatively show the relationship between the two as shown in the figure below.To increase the redox potential, you can increase HOCI or reduce the pH value.The redox potential is related to pH and residual chlorine, and will not change as an independent variable.
2.The higher the pH, the faster the dissociation will develop to the right; When the pH is close to 2.7, about 90% will exist in the form of HOCI (some in the form of chlorine).When electrolyzing salt water, most of them will become HOCI at pH 5, and 1/2 of them will be HOCI and 1/2 of them will be OCI ions at pH 7.5.When the pH of the solution tends to be acidic, chlorine will be generated.On the contrary, when the pH tends to be alkaline, the specific gravity of hypochlorite ion will increase.
Kill bacteria by chlorinating or oxidizing the protein of microorganisms.Hypochloric acid has chlorination reaction and oxidation reaction related to oxygen component that makes chlorine component attach to the target.In the latter, hypochloric acid solution tends to be acidic, and what substances hypochloric acid will become after reaction with organic substances will change according to different conditions.Hypochloric acid has a very strong bactericidal force.Compared with it, OCI ion has a very weak bactericidal force. CI ion has no bactericidal force.The chlorine ion is not directly related to the bactericidal effect, and the chlorine that becomes the ion has neither oxidizing nor bactericidal effect.Therefore, the root of bactericidal power is not chlorine ion, but hypochloric acid in the pH field of acidic water.Hypochloric acid in electrolytic acid water can rapidly kill bacterial cells.Its principle is to destroy the enzyme of bacteria by releasing oxygen, change the effect on the chemical properties of amino acids, and destroy the enzyme indispensable for the oxidation of glucose, thus causing adverse effects on the metabolic process.There are many theories, which can be considered as the result of the interaction of these mechanisms.
4. Acidity of acidic electrolytic water
The pH of acidic water produced by electrolysis is about 2.7, which is caused by the acidity of hydrochloric acid.Compared with concentrated hydrochloric acid (12N),hydrochloric acid of this degree is very thin.Because hydrochloric acid is a volatile acid, it has few residues and little adverse effects on human skin and mucous membrane.Therefore, there will be no skin burns caused by concentrated hydrochloric acid, and the skin irritation is very slight.
5.Effect of organic matter on germicidal efficacy
When electrolyzed acid water is used for daily clinical use, it should be noted that the presence of organic substances such as blood will sharply reduce the germicidal efficacy.PH cannot be used as an indicator of germicidal efficacy.The oxidation-reduction potential is related to the residual chlorine,so the oxidation-reduction potential can be used as an indicator to a certain extent, but basically the sterilization effect is greatly affected by the amount of hypochlorite.When a small amount of serum is added to the electrolytic acid water, the bactericidal effect will drop sharply.When there are organic substances with concentration higher than 0.1% in the electrolytic acid water, the bactericidal effect will be significantly affected.
6.Sustainability of electrolytic acid water effect
Hypochloric acid is an unstable substance.Its active oxygen has a short life and will decompose due to light, air and other factors.
The definition of effect retention time itself is acceptable to Moling and Moling.It will vary according to the type of machine.
When storing strong acidic electrolytic water at room temperature, it should be kept away from light and sealed for a period of 60 days.About Period for the problem of limited days, please refer to the following.The storage condition is only the case of closed containers, and the period is 15 days;In the case of open containers, the duration is 32 hours.Both hypochloric acid and sodium hypochlorite will be reduced and decomposed due to the influence of heat and ultraviolet light, resulting in the reduction of the redox potential.In addition, it is easy to reduce the redox potential when contacting with organic substances.This material has strong oxidation ability and poor stability. Therefore, it is recommended to keep it in a cool place.Based on the principle that chlorine will make potassium iodide starch test paper cyan, it can be used as a simple method to test the bactericidal power.When the electrolytic acid water is poured into the liquid storage tank for use, because it is an open container, the residual chlorine concentration will be weakened, and its weakening degree will be rapidly deactivated according to the amount of pollution (organic matter) by hand or mop and the frequency of use. Therefore, it needs to be replaced every time it is used.
7.Acute toxicity and chronic toxicity
It is reported that electrolytic acid water has destructive effects on various cultured cells and human lymphocytes.The damage to cells is caused by chlorine, and its effect is very small compared with other disinfectants.In the future, electrolytic acid water will be recognized as a medical product, and it needs to be tested and verified in many aspects, such as acute toxicity, subacute toxicity, primary skin irritation, continuous skin irritation, variability, reproductive toxicity, eye irritation, and sensitization.At present, there is no research report that this substance has special toxicity to organisms.
8.Use in hospital
The three major elements of traditional disinfectants are contact time, use temperature and concentration.Compared with traditional disinfectants, there is no special requirement for the relationship between the three elements and electrolytic acidic water.Therefore, it is necessary to formulate a new concept for electrolytic acid water.The method of evaluating its disinfection effect based on the results of In Vitro is being discussed.The effect of water cluster on washing effect is expected.This electrolytic acid water can be understood as<washing water with sterilization effect>.
8.1 Daily use method
1) It is used for impregnation method after washing non-metallic materials once
2) Sanitary hand washing under flowing acidic water
3) Sterilize food materials and utensils in the kitchen
When acid water is used for daily hand washing, in some cases of rough hands, the number of bacteria will increase after hand washing.Hand washing with acid water cannot kill the bacteria attached to the fingers, and is not suitable for finger disinfection in the operating room.
8.2 For clinical treatment
At present, the safety of organisms has not been confirmed, and has not been recognized as medical materials; In addition, there must be organic substances attached to the mucosa, so the effect of acidic water may be affected.
The following centralized uses are mentioned in the report and literature of the Society. ① Wipe the patient, ② at the wound
Home, ③ oral care, ④ bedsore care, ⑤ specific dermatitis, bacterial dermatitis, ⑥ stomatology field.
When used for bladder cleaning and bedsore treatment, the washing effect is more expected than the sterilization effect.During use, it is also necessary to pay attention to the removal of the leaching solution and necrotic substances before use.The pH of sodium hypochlorite on the market is 8.2, HOCI is 15% and OCI is 85% at the actual concentration of 200PPM.The existing HOCI of 30PPM is related to the effective chlorine concentration of acidic electrolytic water(HOCI is 30PPM) is basically the same.It is a big problem to use a large amount of it for intraperitoneal cleaning.Therefore, when the safety of acidic water has not been recognized at present, it is necessary to be careful when cleaning the internal organs of the body cavity.