Life in the post-pandemic era – Disinfectant Review [Chlorine Dioxide]

Many readers may have had similar confusion. Although chlorine dioxide has "chlorine" in its name, it does not belong to "chlorine-containing disinfectants" by definition. The National Health Commission even classified it separately in official guidelines. In this disinfectant review, we will share some information about chlorine dioxide.
The contents of this issue mainly include:

• Basic information about chlorine dioxide
  Disinfection principle of chlorine dioxide
  Main uses of chlorine dioxide
  Chlorine dioxide and coronavirus
  Compounding of chlorine dioxide

  Risks of using chlorine dioxide

  Other matters regarding chlorine dioxide (sustained release related)

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1. Basic information about chlorine dioxide

Chlorine dioxide is an inorganic compound with the chemical formula ClO2. It is a yellow-green to orange-yellow gas under normal temperature and pressure. Chlorine dioxide has bleaching properties and is mainly used for bleaching pulp and paper, fiber, wheat flour, starch, refining and bleaching oils, beeswax, etc. In addition, due to its strong disinfection ability, it is often used as a drinking water disinfectant to replace traditional liquid chlorine disinfection.

 

2. Disinfection principle of chlorine dioxide

Chlorine dioxide can undergo oxidation-reduction reactions with some soluble enzymes in microorganisms, destroy their structures, hinder protein synthesis, or limit specific adsorption, inhibiting the infection of host cells by microorganisms. Chlorine dioxide can effectively kill hepatitis B virus, respiratory viruses, etc. When the pH value is in the range of 6 to 9, the higher the pH value, the better the bactericidal effect. Chlorine dioxide with a concentration of 5.0 mg/L can eliminate Pseudomonas aeruginosa and Staphylococcus aureus in the water.

 

3. Main uses of chlorine dioxide
Chlorine dioxide is widely used in bleaching, water treatment, food industry disinfection and other fields. Due to its relatively unique properties, it can be effective even at low concentrations.
Bleaching can be applied to textiles, paper and food (fungi or bamboo shoots, etc.).

Deodorization removes odors by interacting with sulfides in the air and iron and manganese compounds in water.

For sterilization, chlorine dioxide itself is a broad-spectrum and highly efficient bactericide. At a concentration of 0.1ppm, it can kill many pathogenic bacteria such as Escherichia coli and Staphylococcus aureus.

Water treatment, due to its good deodorization and sterilization effects, chlorine dioxide is widely used in many fields that require water, such as drinking water, sewage treatment, industrial water and aquaculture. The use of chlorine dioxide in water treatment will lead to the formation of chlorite as a by-product. The current U.S. EPA standard for chlorite in drinking water is no more than 0.8 mg/L. my country’s latest national drinking water standard Then it is required to be no more than 0.7mg/L.

Disinfection, chlorine dioxide can be used as a fumigant to "disinfect" fruits that are prone to mold and yeast, such as blueberries, raspberries, and strawberries, and can also be used to disinfect the surfaces of various physical therapy equipment.

For insecticide, studies have proven that gaseous chlorine dioxide with a concentration of 362 ppm or above can effectively kill bed bugs.

In my country's GB/T 26366-2010 "Hygienic Standard for Chlorine Dioxide Disinfectant", it stipulates the physical and chemical indicators of chlorine dioxide, heavy metals, arsenic and stability, as well as microbial killing indicators (including Escherichia coli, Staphylococcus aureus, aeruginosa, etc. albicans, Mycobacterium chelonae subspecies abscessus, poliovirus, and Bacillus subtilis var. black spores).
There are currently two types of chlorine dioxide mainly used for daily disinfection. One is stable chlorine dioxide solution, which can be diluted or used directly; the other is "solid chlorine dioxide" (disinfection tablets/effervescent tablets) , its main composition is generally an active ingredient (usually a mixture of sodium chlorite, anhydrous sodium sulfate, sodium oxysulfate and sodium chlorate) and an activator (usually citric acid or oxalic acid). When mixed with water, it will produce Chlorine dioxide serves as the actual active ingredient. Under normal circumstances, the effective content of chlorine dioxide accounts for about 70% of the reactants (there are differences between different products).

 

 

 

4. Chlorine dioxide and the new coronavirus

(1) Chlorine dioxide disinfection solution
In fact, it was confirmed as early as the beginning of 2020 that chlorine dioxide can effectively kill the new coronavirus. The National Health Commission issued the "Notice of the General Office of the National Health Commission on Issuing Guidelines for the Use of Disinfectants" in mid-February 2020. The "Disinfectant Usage Guide" contains clear instructions on how to use chlorine dioxide. Readers with more conservative preferences can directly adopt the usage suggestions in the "Guide". According to relevant research, organic matter or reducing substances will affect the disinfection effect of chlorine dioxide, so it is usually recommended to appropriately increase the concentration of the disinfection solution.

3 chlorine dioxide disinfectant

3.1 Active ingredients

After activation, the chlorine dioxide content is ≥2000mg/L. There is no need to activate the product according to the product instructions.

3.2 Scope of application

Suitable for disinfection of water (drinking water, hospital sewage), object surfaces, eating and drinking utensils, food processing tools and equipment, fruits and vegetables, medical equipment (including endoscopes) and air.

3.3 How to use

When disinfecting the surface of an object, use a concentration of 50mg/L to 100mg/L for 10min to 15min. When disinfecting drinking water, use a concentration of 1mg/L to 2mg/L for 15min to 30min. When disinfecting hospital sewage, use a concentration of 20mg/L. L～40mg/L, the effect is 30min～60min; when disinfecting indoor air, follow the product instructions.

PS: When the density is 1kg/L, 1mg/L=1ppm (please pay attention to the density difference of different solutions when preparing it at home, it is recommended to refer to the product manual)

On the other hand, with the deepening of research during the pandemic, researchers have also found that the actual killing time of chlorine dioxide against the new coronavirus is shorter. First, 80ppm of chlorine dioxide can complete most of the killing of the new coronavirus within 10 seconds. Inactivation (FBS concentration is used to simulate the impact of organic matter on disinfection effect), 8ppm chlorine dioxide can complete partial inactivation.

In this study, the researchers also tried the antivirus effect of 24ppm chlorine dioxide. Judging from the results, when there is no FBS, 24ppm chlorine dioxide can reduce the virus titer below the detection limit within 10 seconds; when 1.0% FBS is present, the inactivation of the new coronavirus can be completed within 30 seconds. .

That is to say, under normal circumstances, a chlorine dioxide disinfectant of about 30 ppm can complete the disinfection of the new coronavirus on the surface of most objects within 30 seconds.
(2) Inhibit virus binding activity

Studies have shown that the binding activity of the human body's ACE2 receptor protein and the new coronavirus spike protein decreases as the concentration of chlorine dioxide increases. The half-bound inhibitory concentration of chlorine dioxide solution is 0.4ppm for the original strain, 0.5ppm for the alpha strain, and 0.4ppm for the beta strain. However, this also led to a large number of people in the United States in the early days of the pandemic trying to directly drink or inject disinfectant solutions containing chlorine dioxide for the purpose of preventing or treating COVID-19. (The relevant journey of the Peruvian people is even more difficult)

 

"Despite previous warnings, the FDA is concerned that we are still seeing chlorine dioxide products sold with misleading claims that they are safe and effective in treating illnesses, now including COVID-19. Selling these products could harm a person health and delays appropriate medical care," said FDA Commissioner Stephen M. Hahn, M.D., "We will continue to take action and continue our efforts to monitor fraudulent treatments during this public health emergency and remind the public about the health care providers seek medical help.”

(3) Spraying and air disinfection

Although chlorine dioxide, whether in the form of gas or disinfectant solution, can theoretically be used for air disinfection, from a safety perspective it is not recommended that readers try it on their own at home or in general office areas. A more suitable application scenario should be a larger workshop or Factory buildings and other commercial scenes.

5. Compounding of chlorine dioxide
According to relevant research, chlorine dioxide has certain viscosity-increasing properties for liquid detergents. At the same time, it has the characteristics of enhancing detergency, reducing surface tension, increasing foaming power, and increasing disinfection and sterilization functions of liquid detergents. When the concentration of chlorine dioxide is 4mg/mL, the performance of the liquid detergent reaches the ideal level, and the detergency is higher than the general ratio. When the ratio concentration is high, the foaming power of liquid detergent will decrease. Therefore, if you want to wash fruits, vegetables and tableware, you can use a concentration ratio with low foaming power; a concentration ratio with high foaming power is more suitable for washing clothes and other textiles. However, you need to pay attention to its bleaching effect.

6. Risks of using chlorine dioxide

Although in most cases the risk is very low when used according to the concentration configured by the merchant, there are still some things to pay attention to:
Chlorine dioxide is a topical disinfectant and should not be taken orally.

Chlorine dioxide should not be mixed with other disinfectants, alkalis or organic substances to avoid danger.

Chlorine dioxide has a bleaching effect. Please pay attention to the concentration and color of the objects being disinfected.

Chlorine dioxide is corrosive to metals. Please avoid using metal spray bottles and disinfecting metal objects.

Wear gloves when using it to avoid high-concentration disinfectants coming into contact with the skin and being inhaled into the respiratory tract. If it accidentally splashes into the eyes, rinse with water immediately. In severe cases, seek medical treatment.

Chlorine dioxide easily absorbs moisture and decomposes when exposed to light, so it needs to be stored in a dry and ventilated place.

Chlorine dioxide easily decomposes when heated, so please do not use hot water when preparing it; do not heat it as it may explode.

When using tablets to prepare disinfectant solution, be sure to add water first and then add tablets to avoid explosion due to heat generated by the reaction (for the same reason, please do not put tablets directly into the toilet or sewer).

Chlorine dioxide gas is not as stable as the solution, and 5ppm is somewhat irritating. Excessive inhalation is harmful to the human body. Its toxicity is similar to that of chlorine and can corrode the eyes and respiratory organs. At high concentrations, it can invade the central nervous system and cause death. According to relevant regulations of the U.S. Department of Labor, the allowable concentration in the air is 0.1ppm (0.3mg/m³).

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7. Other matters concerning chlorine dioxide
(1) Chlorine dioxide disinfection card
Although the principle of using slow-release gaseous disinfection factors to disinfect the air has been proven feasible by many authoritative experiments at home and abroad, the space that a disinfection card can disinfect is very limited, depending on whether you place it in a closed space or in a closed space. Still open space. As a carry-on item, its release concentration and external interference determine that it may be ineffective in most cases.

In response, the U.S. EPA is taking steps to protect American consumers from being deceived by disinfectants claiming to kill the coronavirus. The EPA reiterated that disinfection products must be registered under the FIFRA regulatory framework. Unregistered products will be stopped from sale and fined in accordance with the law. It also disclosed some unregistered products, including chlorine dioxide air disinfection cards and other products. .
(2) Chlorine dioxide sustained-release gel
A reader once left a message asking me whether sustained-release gel is an "IQ tax" like disinfection cards. In fact, it can essentially be understood as a large "chlorine dioxide disinfection card", but it is precisely due to the increase in its volume and effective content, as well as the optimization of its slow-release technology, that it becomes effective in some specific environments. The release concentration of the same type of chlorine dioxide sustained-release gel can be adjusted according to the adjustment, generally between 0.03~0.1ppm. Theoretically, it can have a certain disinfection effect in some small confined spaces, such as the bathroom mentioned above. , large wardrobe, small buffer room or temporary small cleaning area. Before the COVID-19 pandemic, the main application of commercially available chlorine dioxide disinfectant gel was to remove indoor formaldehyde, and the actual effect was very good.

 

But in fact, it seems that scientists have no clear conclusion for the time being as to what concentration of chlorine dioxide gas can be used to inactivate the new coronavirus in space and how long it will take. For reference, chlorine dioxide gas with a concentration of 0.03ppm in the air can help mice in influenza A virus aerosols avoid infection, and it is speculated that the killing time may be 150 seconds. On the other hand, although most cells in the human body are not aware of chlorine dioxide, the lungs are a relatively special entity, and there is currently no clear research on the tolerance of chlorine dioxide in the lungs.

It is also very difficult for ordinary people to accurately detect the content of chlorine dioxide in the air. Therefore, to judge whether a product has a disinfecting effect, you must see a complete scientific evaluation report issued by the testing agency to draw a conclusion. Pay special attention to the application in the report. Key information such as space size and effective time. Another point to note is that the national standards do not require chlorine dioxide-related products to effectively kill the new coronavirus, so third-party test reports usually do not involve the disinfecting effect of the new coronavirus.

In general, chlorine dioxide is a very excellent and cheap disinfectant. It can be used for surface disinfection of objects, fruits and vegetables, etc. in our epidemic prevention life. Regarding its application in sustained release, although there may not be a clear answer for the time being, it is still a method as long as the concentration is controlled well. (If further research is found in the future, it will be shared with everyone.)

The above is all the content shared in this issue. If you have any questions, please leave me a message.

(All pictures in this article are from public sources on the Internet)

Source of work: Danzhai Dayuan