Carbon Dioxide

Chlorine dioxide (ClO₂) is an orange-yellow to yellow-green gas that is internationally recognized as safe, non-toxic green disinfectant.

English name ; Chlorine Dioxide

Chemical formula ; ClO₂

Molecular weight ; 67.46

CAS Registry Number ; 10049-04-4

EINECS accession number ; 233-162-8

Melting point ; -59.5 ℃

Boiling point ; 11 ℃

Water-soluble ; Easily soluble in water

Density ; 3.09 (11 ℃)

Exterior ; Red and yellow gas with a pungent odor

Flash point ; Pointless

Number RTECS ; F03000000

EC Number ; 006-089-00-2

ICSC No. ; 0127

Chemical Properties

Red and yellow with a strong pungent odor of gas: 11 ℃ when liquefied into a red-brown liquid, -59 ℃ when solidified into orange-red crystals. There are special incentives similar to the smell of chlorine and nitric acid. Red-brown liquid, solid orange-red. Boiling point 11 ℃. Vapour density of 2.3g / L. In case of hot water is broken down into hypochlorous acid, chlorine, oxygen, the light is also easy to decompose, its solution is relatively stable in the dark and cold. Chlorine dioxide can react with many chemical explosive reaction. Heat, vibration, impact and friction are quite sensitive, easily decomposed explosion. When heated and in case that the light or the like can promote oxidation of organic substances, can promote decomposition and easy to cause an explosion. If diluted with air, carbon dioxide, nitrogen and other inert gases, explosive is reduced. Is a strong oxidizing agent, which is 2.6 times the available chlorine chlorine. Unlike many substances can react violently. Are highly corrosive.

Solubility: easily soluble in water without reacting with water, almost hydrolysis (aqueous solution of chlorite and chlorate only 2% solute) occurs; solubility in water is chlorine 5 to 8 times. Soluble alkali solution to generate chlorite and chlorate.

Solubility in water: 20 ℃ when 0.8g / 100ml, 8300mg / L

Bond: Cl atoms sp hybrid orbitals to form σ bond, molecule is V-shaped molecule. A chlorine atom in the electron perpendicular O-Cl-O plane, and four electrons and O, O atom 3 5 forming electronic π bond (delocalized π bond).

Oxidation:

1. manganese oxide

Chlorine dioxide can be oxidized to bivalent manganese tetravalent manganese, so as to form a water-insoluble manganese dioxide (MnO2), namely:

2ClO2 + 5Mn + 6H2O = 5MnO2 + 12H + 2Cl by peroxide, chlorine dioxide for manganese removal rate of 69% to 81% manganese and chlorine removal rate of only 25%, the general dosage of chlorine dioxide 5.0mg / L.

2. The oxidation of iron

Chlorine dioxide is also capable of oxidizing the divalent iron into trivalent iron to form ferric hydroxide precipitate, namely:

ClO2 + 5Fe (HCO3) 2 + 13H2O = 5Fe (OH) 3 + 10CO3 + Cl + 21H through peroxide, chlorine dioxide, iron removal rate of 78% to 95%, while the chlorine removal rate of only 50% iron so, the general dosage of chlorine dioxide 2.0mg / L.

3. Oxidation of sulfides

Chlorine dioxide at a pH range of 5 to 9, will soon sulfide (S) is oxidized to sulfate (SO4), namely:

8ClO2 + 5S + 4H2O = 5SO4 + 8Cl + 8H when chlorine dioxide dosage of 3.0mg / L, the sulfur removal efficiency was 81%.

4. Oxidation of cyanide

Chlorine dioxide can be oxidized to carbon dioxide and nitrogen, cyanide, namely:

2ClO2 + 2CN = 2CO2 + N2 + 2Cl When the cyanide concentration of 3.0mg / L, the dosage of chlorine dioxide was 5.0mg / L, which cyanide is generally greater than 85% removal efficiency.

Advantage

Broad spectrum: can kill viruses, bacteria, protozoa cell organisms, algae, fungi and various spores and sporulation

Efficient: 0.1ppm next to kill all bacteria and many pathogens, 50ppm completely kill bacteria, virus, phage and bacterial spores

By temperature and ammonia little effect: at low and high temperatures are basically the same bactericidal effect

Wide pH range: maintaining high disinfection efficiency in the range of pH2 ~ 10

Security no residue: chlorination reaction does not occur with organic matter, no mutagenic substances and other toxic substances

The human body without stimulation and other advantages: less than 500ppm, its impact can be ignored, 100ppm or less did not have any impact on people

Safety

Large number of foreign experimental studies have shown that chlorine dioxide is a safe, non-toxic disinfectant, no "three-induced" effect (carcinogenic, teratogenic, mutagenic), but does not occur with organic chlorination disinfection process generates have a "three-induced effect" of organic chloride or other toxic substances. But because chlorine dioxide has strong oxidation ability, should be avoided at high concentrations (> 500ppm) use. When used at a concentration of less than 500ppm, its impact on the human body can be ignored and will not have any effect on the human body 100ppm or less, including physiological and biochemical aspects. Nor any skin sensitization. In fact, the use of a conventional chlorine dioxide concentration is much lower than 500ppm, typically only about several tens of ppm. Therefore, chlorine dioxide has also been internationally recognized as safe, non-toxic green disinfectant.

Got goldfish and mouse toxicity test toxicity test in two things: safe concentration a.ClO2 was 0.75mg / 1, b by a mouse acute oral toxicity test, ClO2 belongs to actually nontoxic water treatment agent.

Acute toxicity test, the highest dose filling 10000mg / kg when stabilized chlorine dioxide, mice no noticeable symptoms, diet and activity were normal. During the test animals in each group were not a death watch. After calculation, the oral LD50> 10000mg / kg.

Acute skin irritation, observations suggest that the removal of 1 to 48 hours after drug applicator rabbit back parts of the skin erythema and edema were irritation response was 0 points.

Acute ocular mucous membrane irritation, instillation into the conjunctival sac of rabbits after concentration 9.7 ~ 11.4mg / L stabilized chlorine dioxide solution 5s, rinse with saline. Rabbit mild conjunctival vascular congestion within 6h, 24h until symptoms disappeared, the symptoms completely disappeared 48h. 48h rabbit eye irritation score index is 0, is non-irritating substances.

Use

The specific purpose

As oxidants, sweetening agents, biocides, preservatives, bleaching agents. Chlorine dioxide because of its bactericidal ability, there is no harm to humans and animals and the environment does not cause secondary pollution has attracted people of all ages. Chlorine dioxide does not cause cancer is not only a broad spectrum of environmentally friendly disinfectant, but also sterilization, food preservation, deodorant, etc. showed a significant effect.

Chlorine dioxide can also be used for bleaching, such as textile and paper element using chlorine bleach can be replaced with chlorine dioxide.

The main purpose of chlorine dioxide disinfection of water, and flour and wood pulp bleaching.

It is very effective against viruses, bacteria and including Giardia lamblia (Giardia lamblia) and Cryptosporidium (Cryptosporidium) and other protists caused by cysts and oocysts.

From 1956 Brussels, Belgium by the chlorine into the water disinfectant chlorine dioxide, chlorine dioxide began to be widely used.

After Hurricane Katrina struck New Orleans, chlorine dioxide was used to clear the danger after being flooded houses on the mold. The Chinese government on March 6, 2006 notice of chlorine dioxide water disinfectant.

1. Sterilization, disinfection

⑴ chlorine dioxide disinfection of drinking water purification is a very effective drinking water purifying agent, including a good deodorant and decolorization ability, efficient bactericidal and virucidal capacity at low concentrations. When the capacity of chlorine dioxide for disinfection of water, in a concentration of 0.5 ~ 1mg / L, within 1 minute of 99% can kill bacteria in water, the sterilization effect is 10 times than chlorine, sodium hypochlorite twice, the inhibition of virus 3 times higher than chlorine, 1.9 times higher than ozone. Chlorine dioxide sterilization also fast, wide pH range (6-10), is not affected by water hardness and how much salt, bactericidal effect can be maintained for a long time, can efficiently eliminate protozoa, spores, fungi, algae and biofilms, does not generate trihalomethanes and chlorinated phenols, oxidation of many organic compounds can, thereby reducing the toxicity and mutagenic properties of water and other characteristics.

⑵ sterilization of air to air containing a large number of pathogenic bacteria can, in particular, catering establishments and food processing production plant type and quantity of microorganisms in the air are many and complex, these microorganisms commonly used UV sterilization, but because of the indoor air relative humidity, ultraviolet germicidal effect is not ideal. The preparation of chlorine dioxide sterilization ability, the rapid decomposition of no residue, is very suitable for the premises of the air spray sterilization and disinfection of the catering and food processing industry. In addition, spring and autumn season is more colds, bronchitis and other diseases, can be used chlorine dioxide disinfection of the environment, not only can kill pathogenic microorganisms, but also eliminate odors and fresh air. Therefore, chlorine dioxide is a very good prevention "SARS" environment disinfectant.

⑶ of kitchen utensils, food disinfection of kitchen appliances, machinery and equipment, food machinery equipment, containers, etc. If you do not thoroughly disinfected, likely to cause pollution of food, causing food poisoning. With chlorine dioxide on kitchen utensils, food machinery equipment, containers for disinfection, can kill E. coli, Staphylococcus aureus and the like.

⑷ chlorine dioxide in the medical field for oral rinse, which can effectively control gingivitis, plaque bacteria and bad breath, used as a bath or washing, to prevent a variety of diseases, and so on. In the 1998 floods, the flood fighters chlorine dioxide disinfectant wash, bath, brush, feet, foam wash underwear, with its magical effect again be verified. Practice has proved that chlorine dioxide on the prevention and treatment of pink eye, skin and deodorant with good results.

⑸ aquaculture, livestock and poultry disinfection: chlorine dioxide agent for the treatment of aquaculture fish, shrimp, crabs, turtles, frogs and other bacterial, viral diseases. Common carp, grass, eel, tilapia, etc. red skin, rotten gills, hemorrhagic septicemia, enteritis, unfinished, fungus, etc; shrimp virus disease, black gills, white problems, diseases such as printing; crab class rotten gills, edema, enteritis, ashore disease, tremor; turtle skin fester disease, red, white shell disease, hemorrhage, perforation of disease; frog skin disease, eye disease and other diseases have a unique effect, and can remove the water smell improve water quality, increase the oxygen content of the water.

Bactericidal effect: Chlorine dioxide is a broad-spectrum, highly effective sterilizing agent. The results show that many foreign chlorine dioxide in very low concentrations (0.1ppm), the will kill many, such as Escherichia coli, Staphylococcus aureus and other pathogens. Even in interfering organics, at a concentration of several tens of ppm, may be completely kill all microorganisms vegetative bacteria, virus, bacteriophage and bacterial spores, etc.

Chlorine dioxide disinfectant application history

Human use of chemical disinfectants for disinfection from the early 19th century began. After 1820, the first generation of chemical disinfectants bleach come out, people will mainly be used to disinfect drinking water and the treatment of infected wounds, and have achieved good results, has opened up a chemical sterilization of the first milestone. Since then, people have been found in the second generation of disinfectant ethylene oxide, the third generation of disinfectant glutaraldehyde. A new generation of highly efficient chemical disinfectants in the long-awaited finally come out, this is referred to as the fourth generation of disinfectant chlorine dioxide. Chlorine dioxide was born in 1811, people did not use it early sterilization until 1940, after the industrial production of sodium hypochlorite, people began large-scale use. 1940 United States Niagara Falls it pioneered drinking water treatment, and achieved good results, then quickly extended to the world. People have found that when using chlorine to disinfect drinking water, water, organic matter and chlorine substitution reaction will occur, producing organic chlorine compounds, organic chlorine accumulates in the human body produce chronic cumulative toxicity, but also induce cancer, the upcoming World Conservation Union a total ban on the use of chlorine for drinking water disinfection, recommended broad-spectrum, strong oxidizing efficient disinfectant chlorine dioxide disinfection of drinking water. Chlorine dioxide has been the World Health Organization (WHO) as AⅠ level disinfectant.

China applied chlorine dioxide disinfection technology began eighties. In 1987, the Guangdong Provincial Health Authority approval which may be used for food sterilization and food preservation equipment, utensils disinfection. 1990 Shanghai health authorities approved it can be used in water treatment, food processing, and aquaculture and deodorization. Ministry of Health is also clear that the year 2000, to gradually replace chlorine gas with chlorine dioxide to disinfect drinking water. Chlorine dioxide has been listed as an important prevention of SARS chlorine disinfectant.

Disinfectants Compare

The following table presents a comparison of chlorine dioxide disinfectant and other commonly used disinfectant: Properties of chlorine dioxide chlorine preparations quaternary peracetic acid

2, fresh

⑴ fresh food is non-toxic chlorine dioxide disinfectant, generally using smaller concentrations, can be directly used for fruit, vegetables, meat sterilization, and preservation. Fruit, vegetables, soak a while in the chlorine dioxide solution that is able to kill microorganisms without reaction with fatty tissue without damaging the fiber vegetables and fruits and vegetables taste, nutrition, without any damage, and without then rinse. In circulation, some not washing fruits and vegetables, available solid chlorine dioxide loaded with crates of fruits and vegetables together, can be a long slow release of chlorine dioxide, not only sterilization, but also to achieve Preservation. By chlorine dioxide solution to soak the fish, chicken, poultry, not only can eliminate stench, but also effectively control microbial growth and prolong the storage period, and can keep the delicious taste. Treatment with chlorine dioxide eggs, fresh effect is also good, does not affect the eggs hatch.

⑵ deodorant, odor and chlorine dioxide in the air can be a compound of iron and manganese in water and phase separation of sulfur compounds, but does not react with ammonia, thus eliminating air and water in addition to odor. Refrigerator with a solution of chlorine dioxide scrubbing, can eliminate the role of odor. In the bathroom available chlorine dioxide solution spray, can quickly remove the odor.

Developed countries have applied to almost all chlorine dioxide disinfection required fields. In China, the application of chlorine dioxide has just started, there is reason to believe that in the near future, chlorine dioxide production and life will become essential daily necessities, and its prospects is unlimited.

3. bleach

⑴ for textile yarn, linen and other natural fibers bleaching.

⑵ paper pulp bleaching, improve the whiteness.

(3) Edible bamboo shoots food bleaching

Applications

1. Various occasions of life, drinking water disinfection

2. Sterilization hotels, homes, stalls utensils and sanitation and disinfection of air environment

3. Terminal sterilization of food, beverage plants, industrial fermentation equipment, pipes, container sterilization

4. Dairies, slaughterhouses sterilization pipelines, processing facilities and the environment;

5. Sterilization of hospital sewage treatment;

6. Swimming pool circulating water bath water sterilization

7. Medical, health, clinical equipment disinfection, sterilization, deodorant and anti-mildew treatment

8. Sterilization preservation families, hotels, restaurants, fruits and vegetables, fish food and the final rinse and disinfection sanitary ware;

9. High-rise building secondary water supply disinfection

10. Configure various oral disinfectant, deodorant and wound fluid as cleaning fluid

11. Environmental clean air in public places and air conditioning and ventilation systems, disinfection, deodorization. Disinfect patient and his family, the patient items

12. Livestock farms and homes of drinking water disinfection, fish disease control, water disinfection.

13. Sterilization process fresh mushrooms fungus production

14. Fish and shrimp processing control bacteria, E. coli contamination and preservation

15. Cocoon farming disinfection apparatus

16. Water reuse in sterilization and deodorization

17. Flour with a variety of foods bleach

18. Bleaching agent in paper making, printing and dyeing industry

19. Industrial cooling circulating water sterilization algaecide

20. Oil pipeline SRB eliminated,

21. Broken cyanide plating treatment of wastewater containing cyanide

22. Phenol removal of phenol wastewater treatment

23. Decolorization of Dyeing Wastewater Treatment

24. Supporting a variety of industrial sewage and chemical oxidation treatment of odorous gases and environmental protection equipment.

25. States on the use of chlorine dioxide range of legal provisions

Influences Approved by the state agency use of time

1992 WHO  Drinking water disinfection

1987 Germany Drinking water disinfection

1985 United States FDA Food processing equipment sterilization

1987 United States EPA Food processing plants, breweries, restaurants, environmental disinfection

Sterilization and mildew hospitals, laboratories and non-empty hard surface of the device

1989 United States EPA Store water disinfection; place to live animals such as poultry, pigs, dogs rings disinfection deodorant

1988 Japan The Ministry of Health Food Drinking water disinfection

1987 Australia Australia Department of Health Food Additives No. 926, food bleaches

1987 China Health department Food industry, medical, pharmaceutical, animal husbandry, Disinfection and sterilization of aquaculture, environmental and other public areas

1996 China Health department Aquatic products and fruit and vegetable preservation of food additives

2002 United States FDA Food processing equipment, piping, equipment and technology, particularly in milk processing plants

2005 China Health department Drinking water disinfection

Factors

Stability of chlorine dioxide disinfectant chlorine dioxide to chlorite form, activated by an activating agent to release chlorine dioxide has bactericidal action. Disinfection with pure chlorine dioxide disinfectant solution similar. The rate of release of chlorine dioxide disinfectant and pH have a certain relationship, quick release under acidic conditions, pH value> 5.0 disinfectant chlorine dioxide slows down the rate of release, activation incomplete sterilization weak.

Chlorine dioxide disinfectant with the concentration increases, strengthening the role of sterilization, with 500ppm chlorine dioxide disinfectant solution to kill Candida albicans, the role of 1min, kill rate of 100%; while with 250ppm, the role of 10min, to reach 99.99% .

With increasing temperature, sterilization strengthened. With 0.8mg / L chlorine dioxide disinfectant to kill 99% of the polio virus, when the temperature is 5 ℃, the need to 6.8min, when the temperature is 15 ℃, the need to 1.7min, when the temperature is 25 ℃, need 1.5min.

Organisms of chlorine dioxide disinfectant sterilization effect significant effect, 2% yeast bacteria used in the test, and then chlorine dioxide disinfectant to sterilize test results, 100min only kill 99.99% of E. coli , without adding yeast who act only 5min to kill them all.

Sterilization to smell, chlorine dioxide is unique.

Testing equipment

1, the portable chlorine dioxide detector

HFPCY-CLO2 portable chlorine dioxide detector, can continuously detect the operating environment in the concentration of chlorine dioxide leak. Pocket chlorine dioxide detector is a natural diffusion to detect gas concentrations, the use of imported electrochemical sensor, with excellent sensitivity and excellent repeatability; mini chlorine dioxide detector using the embedded micro-control technology, simple menu operation, function range, high reliability, overall performance lead at home.

2, fixed chlorine dioxide detection probe

HFTCY-CLO2 industrial fixed chlorine dioxide detection probe by the alarm controller and chlorine dioxide detectors, alarm controller can be placed in the duty room, main control for each monitoring point, chlorine dioxide gas detector installed in the most easy to leak location, the core component is a built-in gas sensors, sensors to detect the concentration of gas in the air. Detectors convert chlorine dioxide concentration detected by the sensor into an electrical signal, transmitted through the cable to the controller, the higher the gas concentration, the stronger the electrical signal when the gas concentration reaches or exceeds the alarm set point alarm control, alarm signals an alarm and initiate a solenoid valve, exhaust fan endures associated equipment, automatically excluded risks. Fixed chlorine dioxide detection probe is widely used in petroleum, chemical, metallurgy, electricity, coal, water and other environments, effectively prevent poisoning, explosion and other accidents.

Harm

Chlorine dioxide has strong oxidation resistance, air volume concentration of more than 10% there will be explosive, but the solution is very safe (water content of more than 30% explosive). It can occur with many chemicals explosive reaction, heat, vibration, impact and friction, very sensitive, easily decomposed explosion.

development of

As early as 1811, US scientists H.Davery use KClO3 aqueous hydrochloric acid reaction, first synthesized and collected chlorine dioxide gas. But until the 1930s, ClO2 was able to safely and cost-effectively scale production, began an extensive application of industrialization. In 1944, chlorine dioxide as a disinfectant for the first time in New York, USA Niagara Falls, drinking water treatment. The late seventies of the last century, since the successful development of chlorine dioxide stabilizer, chlorine dioxide as a bleaching agent and disinfectant, has been widely used in pulp bleaching, disinfection and water purification and other fields of food processing, full exhibit strong bleaching and disinfection it has the ability.

Chlorine dioxide is internationally recognized as a new generation of highly efficient, broad-spectrum, safe sterilization, preservative, is the best alternative to chlorine preparations, in developed countries has been widely used. Relevant organizations United States, Western Europe, Canada, Japan and other developed countries such as the US Environmental Protection Agency, the Food and Drug Administration, the US Department of Agriculture have approved and recommended chlorine dioxide for disinfection of food, food processing, pharmaceuticals, hospitals, public environment like , preservation and mildew and other foods. The World Health Organization (WHO) and the World Food Organization (FAO) has also classified as A1 class of chlorine dioxide disinfectant safe and efficient. For the control of drinking water have a "three-induced substance" (carcinogenic, teratogenic, mutagenic), the American and European countries has been widely used alternative to chlorine dioxide chlorine to disinfect drinking water. Around 2006, China began to attach importance to the promotion and application of chlorine dioxide products. On June 1, 2006 promulgated the People's Republic of China national standard stable chlorine dioxide solution (GB / T20783-2006), the Ministry of Health has approved chlorine dioxide as a disinfectant and new food additives.

other

May 1, 2003, "a variety of commonly used method of disinfection of contaminated objects" issued by the National Center for Disease Control recommended that in order to avoid the spread of "atypical pneumonia" and other infectious diseases, dining utensils available 200mg / L chlorine dioxide solution soaking, swimming pool water can 5mg / L chlorine dioxide disinfection.

WHO assessment

Expert Committee on Food Additives JECFA with the composition of the World Health Organization WHO and the UN Food and Agriculture organization of the FAO the safety of products were reviewed, its security level ADI (human intake permissible basis) AI level (even if they are also safe to eat) . Disinfection is the only person to receive this certification. The World Health Organization (WHO) and the United States environmental organizations (EPA) Chinese Ministry of Health, established a new era of green chlorine dioxide disinfectant, with no three-induced (non-carcinogenic, no teratogenicity, mutagenicity), there are three-way ( broad-spectrum, highly efficient, fast) and deodorant, preservation, algae, bleaching peculiar features have been incorporated into the health regulations for use.

Applications and mechanism of chlorine dioxide

Chlorine dioxide sterilization, bleaching, deodorization, sterilization, and preservation of function.

The main mechanism of action is oxidation, the electronic structure of molecules of chlorine dioxide was not saturated, the outer layer of a total of 19 electrons, with a strong oxidizing force, mainly on the wealthy electron (or electron) atomic group (such as those containing sulfhydryl enzymes and sulfides, chlorides) attacks, forced plunder electronics, making physical activity and change the nature of the loss, so as to achieve its purpose.

1, sterilization mechanism

Chlorine dioxide cell wall has strong adsorption and penetration, release atomic oxygen oxidation of the thiol-containing enzymes inside cells play a bactericidal effect.

2, the bleaching effect

Chlorine dioxide bleaching by releasing oxygen and hypochlorite decomposition of pigment to achieve the purpose. He made use bleach instead of chlorine, hypochlorite, etc., can prevent and avoid oxidation fiber decreased fiber strength, and therefore the effect is more comprehensive.

3, deodorizing effect

Chlorine dioxide and odor deodorant because it is substance (such as H2S, -SOH, -NH2, etc.) dehydration reaction and rapid oxidation of the odor substances converted into other substances. And it can prevent decomposition of methionine to ethylene, but also ethylene disrupt preformed, thereby delaying the decay, and kill microorganisms without reaction with a fatty acid does not destroy the structure of the food. Entries Atlas