Ozone production formula. What is ozone

The phrase "ozone layer", which became famous in the 70s. last century, has long been set on edge. At the same time, few people really understand what this concept means and how dangerous the destruction of the ozone layer is. An even greater mystery for many is the structure of the ozone molecule, and in fact it is directly related to the problems of the ozone layer. Let's find out more about ozone, its structure and industrial applications.

What is ozone

Ozone, or, as it is also called, active oxygen, is an azure gas with a pungent metallic odor.

This substance can exist in all three states of aggregation: gaseous, solid and liquid.

At the same time, in nature, ozone is found only in the form of a gas, forming the so-called ozone layer. It is because of its azure color that the sky appears blue.

What an ozone molecule looks like

Ozone got its nickname "active oxygen" because of its similarity to oxygen. So the main active chemical element in these substances is oxygen (O). However, if the oxygen molecule contains 2 of its atoms, then the molecule - O 3) consists of 3 atoms of this element.

Due to this structure, the properties of ozone are similar to those of oxygen, but more pronounced. In particular, like O 2, O 3 is the strongest oxidizing agent.

The most important difference between these "related" substances, which is vital for everyone to remember, is the following: ozone cannot be breathed, it is toxic and, if inhaled, can damage the lungs or even kill a person. At the same time, O 3 is perfect for cleaning the air from toxic impurities. By the way, it is precisely because of this that it is so easy to breathe after rain: ozone oxidizes harmful substances contained in the air, and it is purified.

The model of the ozone molecule (consisting of 3 oxygen atoms) is a bit like the image of an angle, and its size is 117 °. This molecule does not have unpaired electrons, therefore it is diamagnetic. In addition, it has polarity, although it consists of atoms of one element.

Two atoms of a given molecule are firmly attached to each other. But the connection with the third is less reliable. For this reason, the ozone molecule (the photo of the model can be seen below) is very fragile and decomposes shortly after formation. As a rule, oxygen is released during any O 3 decomposition reaction.

Due to the instability of ozone, it is impossible to procure and store it, as well as transport it like other substances. For this reason, its production is more costly than other substances.

At the same time, the high activity of O 3 molecules allows this substance to be the strongest oxidant, more powerful than oxygen, and safer than chlorine.

If the ozone molecule is destroyed and O 2 is released, this reaction is always accompanied by the release of energy. At the same time, for the reverse process to take place (the formation of O 3 from O 2), it is necessary to spend at least it.

In the gaseous state, the ozone molecule decomposes at a temperature of 70 ° C. If it is increased to 100 degrees or more, the reaction will accelerate significantly. The presence of impurities also accelerates the decay period of ozone molecules.

O3 properties

Whatever of the three states ozone is in, it retains its blue color. The harder the substance, the richer and darker this shade.

Each ozone molecule weighs 48 g / mol. It is heavier than air, which helps to separate these substances among themselves.

O 3 is capable of oxidizing almost all metals and non-metals (except for gold, iridium and platinum).

Also, this substance can participate in the combustion reaction, but this requires a higher temperature than for O 2.

Ozone is able to dissolve in H 2 O and freons. In a liquid state, it can mix with liquid oxygen, nitrogen, methane, argon, carbon tetrachloride and carbon dioxide.

How the ozone molecule is formed

O 3 molecules are formed by attaching free oxygen atoms to oxygen molecules. They, in turn, appear due to the splitting of other O 2 molecules due to the effect on them of electrical discharges, ultraviolet rays, fast electrons and other high-energy particles. For this reason, the specific smell of ozone can be felt near sparking electrical appliances or lamps emitting ultraviolet light.

On an industrial scale, O 3 is isolated using electric or ozonizers. In these devices, a high voltage electric current is passed through a gas stream containing O 2, the atoms of which serve as the "building material" for ozone.

Sometimes pure oxygen or ordinary air is put into these devices. The quality of the resulting ozone depends on the purity of the initial product. So, medical O 3, intended for the treatment of wounds, is obtained only from chemically pure O 2.

History of the discovery of ozone

Having figured out what the ozone molecule looks like and how it is formed, it is worth getting acquainted with the history of this substance.

It was first synthesized by the Dutch researcher Martin Van Marum in the second half of the 18th century. The scientist noticed that after passing electric sparks through a container with air, the gas in it changed its properties. At the same time, Van Marum did not understand that he had isolated the molecules of a new substance.

But his German colleague by the name of Scheinbein, trying to decompose H 2 O into H and O 2 with the help of electricity, drew attention to the release of a new gas with a pungent odor. After conducting a lot of research, the scientist described the substance he discovered and gave it the name "ozone" in honor of the Greek word for "smell".

The ability to kill fungi and bacteria, as well as to reduce the toxicity of harmful compounds, which the open substance possessed, interested many scientists. 17 years after the official discovery of O 3, Werner von Siemens designed the first apparatus that could synthesize ozone in any quantity. And 39 years later, the brilliant Nikola Tesla invented and patented the world's first ozone generator.

It was this device that, after 2 years, was first used in France at a drinking water treatment plant. With the beginning of the XX century. Europe begins to switch to ozonation of drinking water for its purification.

The Russian Empire first used this technique in 1911, and after 5 years, almost 4 dozen installations for purifying drinking water using ozone were equipped in the country.

Today ozonation of water is gradually replacing chlorination. Thus, 95% of all drinking water in Europe is purified with O 3. This technique is also very popular in the USA. In the CIS, it is still under study, since, although this procedure is safer and more convenient, it is more expensive than chlorination.

Ozone Applications

Apart from water purification, O 3 has a number of other applications.

• Ozone is used as a bleaching agent in paper and textiles.
• Active oxygen is used to disinfect wines, as well as to accelerate the aging process of cognacs.
• Various vegetable oils are refined with O 3.
• Very often this substance is used to process perishable foods such as meat, eggs, fruits and vegetables. With this procedure, no chemical traces remain, as when using chlorine or formaldehydes, and products can be stored for much longer.
• Ozone sterilizes medical equipment and clothing.
• Also purified O 3 is used for various medical and cosmetic procedures. In particular, with its help in dentistry, they disinfect the oral cavity and gums, and also treat various diseases (stomatitis, herpes, oral candidiasis). In European countries, O 3 is very popular for disinfection of wounds.
• In recent years, portable home appliances for air and water filtration with ozone have gained immense popularity.

What is the ozone layer?

At a distance of 15-35 km above the Earth's surface, there is the ozone layer, or, as it is also called, the ozonosphere. In this place, concentrated O 3 serves as a kind of filter for harmful solar radiation.

Where does such a quantity of a substance come from if its molecules are unstable? The answer to this question is not difficult if we recall the model of the ozone molecule and the way of its formation. So, oxygen, consisting of 2 oxygen molecules, entering the stratosphere, is heated there by the sun's rays. This energy is sufficient to split O 2 into atoms, from which O 3 is formed. At the same time, the ozone layer not only uses part of the solar energy, but also filters it, absorbs dangerous ultraviolet light.

It was said above that ozone is dissolved by freons. These gaseous substances (used in the manufacture of deodorants, fire extinguishers and refrigerators), once released into the atmosphere, affect ozone and contribute to its decomposition. As a result, holes appear in the ozonosphere, through which unfiltered solar rays enter the planet, which destructively affect living organisms.

Having considered the features and structure of ozone molecules, one can come to the conclusion that this substance, although dangerous, is very useful for humanity if it is used correctly.

GENERAL INFORMATION.

Ozone - O3, an allotropic form of oxygen, which is a powerful oxidant of chemical and other pollutants that break down on contact. Unlike the oxygen molecule, the ozone molecule consists of three atoms and has longer bonds between oxygen atoms. Ozone is second only to fluorine in terms of its reactivity.

Discovery history
In 1785, the Dutch physicist Van Ma-rum, while conducting experiments with electricity, drew attention to the smell when sparks were formed in an electric machine and to the oxidizing ability of air after passing electric sparks through it.
In 1840, German scientist Scheinbein, engaged in the hydrolysis of water, tried to decompose it into oxygen and hydrogen using an electric arc. And then he discovered that a new gas, hitherto unknown to science, with a specific smell was formed. The name "ozone" was given to the gas by Scheinbein because of its characteristic odor and comes from the Greek word "ozien", which means "to smell".
On September 22, 1896, inventor N. Tesla patented the first ozone generator.

Physical properties of ozone.
Ozone can exist in all three states of aggregation. Under normal conditions ozone is a bluish gas. The boiling point of ozone is 1120C, and the melting point is 1920C.
Due to its chemical activity, ozone has a very low maximum permissible concentration in the air (commensurate with the maximum permissible concentration of chemical warfare agents) 5 · 10-8% or 0.1 mg / m3, which is 10 times more than the olfactory threshold for humans.

Chemical properties of ozone.
First of all, two main properties of ozone should be noted:

Ozone, unlike atomic oxygen, is a relatively stable compound. It decomposes spontaneously at high concentrations, and the higher the concentration, the faster the decomposition reaction. At ozone concentrations of 12-15% ozone can explosively decompose. It should also be noted that the process of ozone decomposition accelerates with increasing temperature, and the decomposition reaction itself 2О3\u003e 3О2 + 68 kcal is exothermic and accompanied by the release of a large amount of heat.

O3 -\u003e O + O 2
O3 + O -\u003e 2 O2
О2 + E- -\u003e О2-

Ozone is one of the strongest natural oxidants. The oxidizing potential of ozone is 2.07 V (for comparison, fluorine has 2.4 V, and chlorine has 1.7 V).

Ozone oxidizes all metals with the exception of gold and the platinum group, additionally oxidizes sulfur and nitrogen oxides, and oxidizes ammonia to form ammonium nitrite.
Ozone actively reacts with aromatic compounds to destroy the aromatic nucleus. In particular, ozone reacts with phenol to destroy the nucleus. Ozone actively interacts with saturated hydrocarbons with the destruction of double carbon bonds.
The interaction of ozone with organic compounds is widely used in the chemical industry and related industries. The reactions of ozone with aromatic compounds formed the basis for deodorization technologies for various environments, rooms and wastewater.

Biological properties of ozone.
Despite the large number of studies, the mechanism is not sufficiently disclosed. It is known that at high ozone concentrations, damage to the respiratory tract, lungs and mucous membranes is observed. Long-term exposure to ozone leads to the development of chronic diseases of the lungs and upper respiratory tract.
Exposure to low doses of ozone has a prophylactic and therapeutic effect and begins to be actively used in medicine, primarily for dermatology and cosmetology.
In addition to the great ability to destroy bacteria, ozone is highly effective in destroying spores, cysts (dense membranes that form around unicellular organisms, for example, flagellates and rhizopods, during their reproduction, as well as in unfavorable conditions for them) and many other pathogenic microbes.

Technological application of ozone
Over the past 20 years, the applications of ozone have expanded significantly and new developments are underway worldwide. Such a rapid development of technologies using ozone is facilitated by its ecological purity. Unlike other oxidants, ozone decomposes in the course of reactions into molecular and atomic oxygen and saturated oxides. All these products, as a rule, do not pollute the environment and do not lead to the formation of carcinogenic substances such as oxidation with chlorine or fluorine.

Water:
In 1857, with the help of the "perfect magnetic induction tube" created by Werner von Siemens, the first technical ozone plant was built. In 1901, Siemens built the first hydroelectric power plant with an ozone plant in Wiesband.
Historically, the use of ozone began with installations for the preparation of drinking water, when in 1898 the first pilot plant was tested in the city of Saint Mor (France). Already in 1907, the first water ozonation plant was built in the city of Beaune Vuayage (France) for the needs of the city of Nice. In 1911, an ozonation station for drinking water was put into operation in St. Petersburg.
Currently, 95% of drinking water in Europe is ozone treated. The USA is in the process of switching from chlorination to ozonation. Several large stations operate in Russia (in Moscow, Nizhny Novgorod and other cities).

Air:
The use of ozone in water purification systems has been proven to be extremely effective, however, the same effective and proven safe air purification systems have not yet been created. Ozonation is considered a non-chemical treatment method and therefore is popular among the population. At the same time, the chronic effect of micro-concentrations of ozone on the human body has not been sufficiently studied.
With a very low concentration of ozone, the air in the room feels pleasant and fresh, and unpleasant odors are felt much less. Contrary to the widespread belief in the beneficial effects of this gas, which is attributed in some avenues to the ozone-rich forest air, in reality ozone, even when very diluted, is a very toxic and dangerous irritating gas. Even low concentrations of ozone can irritate the mucous membranes and cause central nervous system disorders, leading to bronchitis and headaches.

Medical Uses of Ozone
In 1873 Focke observed the destruction of microorganisms under the influence of ozone and this unique property of ozone attracted the attention of physicians.
The history of the use of ozone for medicinal purposes dates back to 1885, when Charlie Kenworth first published his report to the Florida Medical Association, USA. Brief information about the use of ozone in medicine was discovered before this date.
In 1911 M. Eberhart used ozone in the treatment of tuberculosis, anemia, pneumonia, diabetes and other diseases. A. Wolf (1916) during the First World War uses an oxygen-ozone mixture in the wounded with complex fractures, phlegmons, abscesses, purulent wounds. N. Kleinmann (1921) used ozone for the general treatment of "body cavities". In the 30s. 20th century E.A. Fish, the dentist, begins the ozone treatment in practice.
In his application for the invention of the first laboratory device, Fisch proposed the term "CYTOZON", which still appears on ozone generators used in dental practice today. Joachim Hensler (1908-1981) created the first medical ozone generator, which made it possible to accurately dose the ozone-oxygen mixture, and thus made it possible to widely apply ozone therapy.
R. Auborg (1936) revealed the effect of scarring of ulcers of the colon under the influence of ozone and drew attention to the nature of its general effect on the body. Work on the study of the therapeutic effect of ozone during the Second World War was actively continued in Germany, the Germans successfully used ozone for the local treatment of wounds and burns. However, after the war, research was interrupted for almost two decades, due to the emergence of antibiotics, the lack of reliable, compact ozone generators and ozone-resistant materials. Extensive and systematic research in the field of ozone therapy began in the mid-70s, when ozone-resistant polymer materials and convenient ozone installations appeared in everyday medical practice.
Research in vitro , that is, in ideal laboratory conditions, they showed that when interacting with the cells of the body, ozone oxidizes fats and forms peroxides - substances that are harmful to all known viruses, bacteria and fungi. In terms of its action, ozone can be compared to antibiotics, with the difference that it does not “plant” the liver and kidneys, and has no side effects. But unfortunately, in vivo - in real conditions, everything is much more complicated.
Ozone therapy was at one time very popular - many considered ozone to be almost a panacea for all ailments. But a detailed study of the effects of ozone showed that together with the sick, ozone also affects healthy cells of the skin and lungs. As a result, unforeseen and unpredictable mutations begin in living cells. Ozone therapy has never taken root in Europe, and in the USA and Canada, the official medical use of ozone is not legalized, with the exception of alternative medicine.
In Russia, unfortunately, official medicine has not abandoned such a dangerous and insufficiently proven method of therapy. At present, air ozonizers and ozonation installations are widespread. Small ozone generators are used in the presence of people.

OPERATING PRINCIPLE.
Ozone is formed from oxygen. There are several ways to obtain ozone, among which the most common are: electrolytic, photochemical, and electrosynthesis in a gas discharge plasma. In order to avoid unwanted oxides, it is preferable to obtain ozone from pure medical oxygen using electrosynthesis. The concentration of the resulting ozone-oxygen mixture in such devices is easy to vary - either by setting a certain power of the electric discharge, or by regulating the flow of incoming oxygen (the faster the oxygen passes through the ozonizer, the less ozone is formed).

Electrolytic the ozone synthesis method is carried out in special electrolytic cells. Solutions of various acids and their salts (H2SO4, HClO4, NaClO4, KClO4) are used as electrolytes. Ozone is formed due to the decomposition of water and the formation of atomic oxygen, which, when attached to an oxygen molecule, forms ozone and a hydrogen molecule. This method makes it possible to obtain concentrated ozone, but it is very energy-intensive and therefore has not found widespread use.
Photochemical the method of ozone production is the most widespread method in nature. Ozone is formed during the dissociation of an oxygen molecule under the action of short-wave UV radiation. This method does not allow the production of high concentration ozone. Devices based on this method are widely used for laboratory purposes, in medicine and the food industry.
Electrosynthesis ozone is most widespread. This method combines the possibility of obtaining high concentrations of ozone with high productivity and relatively low energy consumption.
As a result of numerous studies on the use of various types of gas discharge for ozone electrosynthesis, devices using three forms of discharge have become widespread:

1. Barrier discharge - the most widespread, it is a large set of pulsed micro-discharges in a gas gap 1-3 mm long between two electrodes separated by one or two dielectric barriers when the electrodes are supplied with alternating high voltage with a frequency of 50 Hz to several kilohertz. The productivity of one installation can range from grams to 150 kg of ozone per hour.
2. Surface discharge - close in shape to a barrier discharge, which has become widespread in the last decade due to its simplicity and reliability. It is also a set of micro-discharges developing along the surface of a solid dielectric when the electrodes are supplied with an alternating voltage with a frequency of 50 Hz to 15-40 kHz.
3. Pulse discharge - as a rule, a streamer corona discharge arising in the gap between two electrodes when the electrodes are supplied with a pulse voltage of duration from hundreds of nanoseconds to a few microseconds.

• Effective in cleaning indoor air.
• Produce no harmful by-products.
• Facilitate conditions for allergy sufferers, asthmatics, etc.

In 1997, the manufacturers of ozonizers Living Air Corporation, Alpine Industries Inc. (now “Ecoguest”), Quantum Electronics Corp. and others who violated the order of the US FTC were administratively punished by the decision of the courts, including a ban on the further activities of some of them in the US. At the same time, private entrepreneurs who sold ozone generators with recommendations to use them in rooms with people received prison terms from 1 to 6 years.
Currently, some of these Western companies are successfully developing an active activity in the sale of their products in Russia.

Disadvantages of ozonizers:
Any ozone sterilization system requires careful safety monitoring, ozone constant testing with gas analyzers, and emergency management of excessive ozone concentrations.
The ozonizer is not designed to work in:

• environment saturated with conductive dust and water vapor,
• places containing active gases and vapors that destroy metal,
• places with relative humidity over 95%,
• in explosion and fire hazardous premises.

Application of ozonizers for indoor air sterilization:

• lengthens the sterilization process in time,
• increases the toxicity and oxidation of the air,
• leads to the danger of explosion,
• the return of people to the disinfected room is possible only after the complete decomposition of ozone.

SUMMARY.
Ozonation is highly effective for sterilizing surfaces and the air environment of a room, however, there is no effect of air purification from mechanical impurities. The impossibility of using the method in the presence of people and the need to carry out disinfection in a sealed room seriously limits the scope of its professional application.

For the first time ozone was obtained and studied by Schönbein in 1840. Ozone is a bluish gas, with a sharp characteristic odor;

Liquefied ozone is a dark blue liquid, solid ozone is a dark purple crystalline mass. Ozone is soluble in carbon tetrachloride, glacial acetic acid, liquid nitrogen, and water. It is formed when a quiet electric discharge is passed through air or oxygen (a fresh smell after a thunderstorm is due to the presence of small amounts of ozone in the atmosphere), oxidation of wet phosphorus, the action of radium rays, ultraviolet or cathode rays on air oxygen, decomposition of hydrogen peroxide, electrolysis of sulfuric acid (and others ...
oxygen-containing acids), the action of fluorine on water, etc. The content in the earth's atmosphere is negligible; air layers near the earth's surface contain less ozone than the upper layers of the atmosphere; at a height of 1.050 m(in the Mont Blanc area) Levy found 0-3.7 mg,at an altitude of 3.000 m—9,4 mg. ozone per 100 m cube air. Apparatus - ozonizers are used in technology and laboratories for ozone production. For ozonation, oxygen or air is passed between two electrodes connected to a high voltage current source.
Pure ozone is released from a mixture of ozone with oxygen when cooled with liquid air. Ozone decomposes easily, and the decomposition of pure ozone is accelerated in the presence of manganese dioxide, lead, nitrogen oxides. In the presence of water, ozone decomposition slows down, dry ozone at 0 ° decomposes 30 times faster than wet ozone at 20.4 °. Ozone has an extremely strong oxidizing effect. It releases iodine from potassium iodide, oxidizes mercury, converts sulphurous metals into sulphate salts, discolors organic dyes, etc. Ozone destroys rubber tubes. Ether, alcohol, luminescent gas, cotton wool in contact with highly ozonated oxygen ignite. Under the action of ozone on unsaturated organic compounds, ozonide addition products are formed. Ozone is used for sterilizing water, for deodorizing - eliminating bad odors, in preparative organic practice.

Physical properties

Chemical properties and methods of preparation

List of used literature

1. Volkov, A.I., Zharskiy, I.M. Big chemical reference book / A.I. Volkov, I.M. Zharsky. - Minsk: Modern School, 2005. - 608 with ISBN 985-6751-04-7.

Molecular formula of ozone in chemistry O 3. Its relative molecular weight is 48. The compound contains three O atoms. Since the formula for oxygen and ozone includes the same chemical element, in chemistry they are called allotropic modifications.

Physical properties

Under normal conditions, the chemical formula of ozone is a gaseous substance with a specific odor that has a light blue color. In nature, this chemical compound can be felt while walking through a pine forest after a thunderstorm. Since the formula of ozone is O 3, it is 1.5 times heavier than oxygen. In comparison with O 2, the solubility of ozone is much higher. At zero temperature, 49 volumes of it easily dissolve in 100 volumes of water. In small concentrations, the substance does not possess the property of toxicity; ozone is poisonous only in significant volumes. The maximum permissible concentration is considered to be 5% of the amount of O 3 in the air. In the case of strong cooling, it easily liquefies, and when the temperature drops to -192 degrees, it becomes a solid.

In nature

The ozone molecule, the formula of which was presented above, is formed in nature during a lightning discharge from oxygen. In addition, O 3 is formed during the oxidation of coniferous resin, it destroys harmful microorganisms, it is considered beneficial for humans.

Getting in the laboratory

How can you get ozone? A substance, the formula of which is O 3, is formed by passing an electric discharge through dry oxygen. The process is carried out in a special device - an ozonizer. It is based on two glass tubes, which are inserted into one another. Inside there is a metal rod, outside there is a spiral. After connecting to the high voltage coil, a discharge occurs between the outer and inner tube, and the oxygen is converted into ozone. The element, the formula of which is presented as a compound with a covalent polar bond, confirms the allotropy of oxygen.

The conversion of oxygen to ozone is an endothermic reaction that requires significant energy consumption. In connection with the reversibility of such a transformation, the decomposition of ozone is observed, which is accompanied by a decrease in the energy of the system.

Chemical properties

The ozone formula explains its oxidizing power. He is able to interact with various substances, while losing an oxygen atom. For example, in the reaction with potassium iodide in an aqueous medium, oxygen is released, the formation of free iodine.

The molecular formula of ozone explains its ability to react with almost all metals. The exception is gold and platinum. For example, after passing metallic silver through ozone, its blackening is observed (oxide is formed). Under the influence of this strong oxidant, rubber degradation is observed.

In the stratosphere, ozone is generated by the action of UV radiation from the Sun, forming a layer of ozone. This shell protects the planet's surface from the negative effects of solar radiation.

Biological effect on the body

The increased oxidizing ability of this gaseous substance, the formation of free oxygen radicals indicate its danger to the human body. What harm can ozone do to humans? It damages and irritates the tissues of the respiratory organs.

Ozone acts on blood cholesterol, causing atherosclerosis. With a prolonged presence of a person in an environment that contains an increased concentration of ozone, male infertility develops.

In our country, this oxidizer belongs to the first (dangerous) class of harmful substances. Its average daily MPC should not exceed 0.03 mg per cubic meter.

The toxicity of ozone, the possibility of its use to destroy bacteria and mold, is actively used for disinfection. Stratospheric ozone is an excellent protective shield for terrestrial life from ultraviolet radiation.

About the benefits and dangers of ozone

This substance is found in two layers of the earth's atmosphere. Tropospheric ozone is dangerous for living beings, has a negative effect on crops, trees, and is a component of urban smog. Stratospheric ozone brings certain benefits to humans. Its decomposition in an aqueous solution depends on pH, temperature, quality of the environment. In medical practice, ozonized water of various concentrations is used. Ozone therapy involves direct contact of this substance with the human body. This technique was first used in the nineteenth century. American researchers analyzed the ability of ozone to oxidize harmful microorganisms, and recommended that doctors use this substance in the treatment of colds.

In our country, ozone therapy began to be used only at the end of the last century. For therapeutic purposes, this oxidizing agent exhibits the characteristics of a strong bioregulator that can increase the effectiveness of traditional methods, as well as prove itself as an effective independent agent. After the development of ozone therapy technology, physicians have the opportunity to effectively fight many diseases. In neurology, dentistry, gynecology, therapy, specialists use this substance to fight various infections. Ozone therapy is characterized by the simplicity of the method, its effectiveness, excellent tolerance, no side effects, low costs.

Conclusion

Ozone is a powerful oxidizing agent that can fight harmful microbes. This property is widely used in modern medicine. In domestic therapy, ozone is used as an anti-inflammatory, immunomodulating, antiviral, bactericidal, antistress, cytostatic agent. Thanks to its ability to restore oxygen metabolism disorders, it provides excellent opportunities for preventive medicine.

Among the innovative methods based on the oxidative capacity of this compound, we highlight the intramuscular, intravenous, subcutaneous administration of this substance. For example, treatment of bedsores, fungal skin lesions, burns with a mixture of oxygen and ozone is recognized as an effective technique.

In high concentrations, ozone can be used as a hemostatic agent. At low concentrations, it promotes repair, healing, epithelialization. This substance, dissolved in physiological saline, is an excellent remedy for jaw debridement. In modern European medicine, small and large autohemotherapy is widely used. Both methods are associated with the introduction of ozone into the body, the use of its oxidizing ability.

In the case of major autohemotherapy, an ozone solution of a given concentration is injected into the patient's vein. Small autohemotherapy is characterized by intramuscular injection of ozonized blood. In addition to medicine, this strong oxidant is in demand in chemical production.

In 1785, the Dutch physicist Van Marum, conducting experiments with electricity, drew attention to the smell when sparks are formed in an electric machine and to the oxidizing ability of air after passing electric sparks through it.

In 1840 the German scientist Scheinbein, engaged in the hydrolysis of water, tried to decompose it into oxygen and hydrogen using an electric arc. And then he discovered that a new, hitherto unknown to science, gas with a specific smell was formed. The name "ozone" was given to the gas by Scheinbein because of its characteristic odor and it comes from the Greek word "ozien", which means "to smell".

In 1857, with the help of the "perfect magnetic induction tube" created by Werner von Siemens, the first technical ozone plant was built. In 1901, Siemens built the first hydroelectric power plant with an ozone plant in Wiesband.

Historically, the use of ozone began with installations for the preparation of drinking water, when in 1898 the first pilot plant was tested in the city of Saint Mor (France). Already in 1907, the first water ozonation plant was built in the city of Beaune Vuayage (France), for the needs of the city of Nice. In 1911, an ozonation station for drinking water was put into operation in St. Petersburg (currently not operating). In 1916, 49 installations for ozonization of drinking water were already in operation.

By 1977, more than 1,000 installations were in operation worldwide. Ozone has become widespread only in the last 30 years, thanks to the emergence of reliable and compact devices for its synthesis - ozonators (ozone generators).

Currently, 95% of drinking water in Europe is ozone treated. The USA is in the process of switching from chlorination to ozonation. Several large stations operate in Russia (in Moscow, Nizhny Novgorod and other cities).

2. Ozone and its properties

The mechanism of formation and molecular formula of ozone

It is known that an oxygen molecule consists of 2 atoms: O2. Under certain conditions, an oxygen molecule can dissociate, i.e. decay into 2 separate atoms. In nature, these conditions are created during thunderstorms with discharges of atmospheric electricity, and in the upper atmosphere, under the influence of ultraviolet radiation from the sun (the ozone layer of the Earth). The mechanism of formation and molecular formula of ozone. However, the oxygen atom cannot exist separately and tends to group again. In the course of this rearrangement, 3-atomic molecules are formed.

Ozone Molecule A molecule consisting of 3 oxygen atoms, called ozone or activated oxygen, is an allotropic modification of oxygen and has the molecular formula O3 (d \u003d 1.28 A, q \u003d 116.5 °).

It should be noted that the bond of the third atom in the ozone molecule is relatively fragile, which causes the instability of the molecule as a whole and its tendency to self-decay.

Ozone properties

Ozone O3 is a bluish gas with a characteristic pungent odor, molecular weight 48 g / mol; density relative to air 1.657 (ozone is heavier than air); density at 00С and pressure 0.1 MPa 2.143 kg / m3. Ozone production

In small concentrations at the level of 0.01-0.02 mg / m3 (five times lower than the maximum permissible concentration for humans), ozone gives the air a characteristic smell of freshness and purity. For example, after a thunderstorm, the subtle smell of ozone is invariably associated with clean air.

As mentioned above, the ozone molecule is unstable and self-decaying. It is due to this property that ozone is a strong oxidizing agent and a disinfectant of exceptional efficiency.

Oxidizing Potential of Ozone

A measure of the effectiveness of an oxidizer is its electrochemical (oxidative) potential, expressed in volts. Below are the values \u200b\u200bof the electrochemical potential of various oxidants in comparison with ozone:

The table shows that ozone is the strongest of all oxidants used in water treatment.

On-site application

The instability of ozone necessitates its use directly at the production site. Ozone is not subject to packaging, storage and transportation.

Ozone solubility in water

According to Henry's Law, the concentration of ozone in water increases with the concentration of ozone in the gas phase mixed into the water. In addition, the higher the water temperature, the lower the ozone concentration in the water.

The solubility of ozone in water is higher than oxygen, but lower than chlorine, 12 times. If we consider 100% ozone, then its maximum concentration in water is 570 mg / l at a water temperature of 20C. The concentration of ozone in the gas at the outlet of modern ozonation plants reaches 14% by weight. Below is the dependence of the concentration of ozone dissolved in distilled water on the concentration of ozone in the gas and the temperature of the water.

Self-decay of ozone in water and in air

The rate of decomposition of ozone in air or water is estimated using the half-life, i.e. the time during which the ozone concentration is halved.

Self-degradation of ozone in water (pH 7)

Self-decay of ozone in air

The tables show that aqueous solutions of ozone are much less stable than gaseous ozone. Data on the decomposition of ozone in water are given for pure water that does not contain dissolved and suspended impurities. The decay rate of ozone in water increases many times in the following cases:

1.if there are ozone-oxidized impurities in the water (chemical water demand in ozone)
2. with increased turbidity of water, because at the interface between particles and water, ozone self-decay reactions proceed faster (catalysis)
3.when exposed to UV irradiation

3. Methods for producing ozone

Currently, 2 methods of ozone production are widely used:

* UV irradiation

* under the influence of a quiet (i.e. scattered, non-sparking) corona discharge

1.UV irradiation

Ozone can be generated near UV lamps, but only in small concentrations (0.1 wt%).

2.Corona discharge

In the same way that ozone is generated by electrical discharges during a thunderstorm, large amounts of ozone are produced in modern electric ozone generators. This method is called corona discharge. High voltage is passed through a gas stream containing oxygen. High voltage energy splits the oxygen molecule O2 into 2 O atoms, which combine with the O2 molecule and form ozone O3.

The pure oxygen entering the ozone generator can be replaced with ambient air containing a high percentage of oxygen.

This method increases the ozone content to 10-15 wt%

Energy consumption: 20 - 30 W / g O3 for air 10 - 15 W / g O3 for oxygen

4. Application of ozone for water purification and disinfection

Water disinfection

Ozone destroys all known microorganisms: bacteria, viruses, protozoa, their spores, cysts, etc .; at the same time ozone is 51% stronger than chlorine and acts 15-20 times faster. The poliomyelitis virus dies at an ozone concentration of 0.45 mg / l in 2 minutes, and from chlorine only in 3 hours at 1 mg / l.

Ozone acts on spore forms of bacteria 300-600 times stronger than chlorine.

Ozone destroys the redox system of bacteria and their protoplasm.

Biological lethal coefficients (BLK *) when using various disinfectants

* The higher the BLK, the more powerful the disinfectant

Comparison of disinfectants

Deodorization of water

Ozonation oxidizes organic and mineral impurities, which are the source of odors and tastes. Water treated with ozone contains more oxygen and tastes like fresh spring water.

Finishing treatment of drinking water on bottling lines
Ozonation on the filling line. Purified and prepared for bottling water is saturated with ozone, completely disinfected and for a relatively short time itself acquires disinfecting properties. This increases the microbiological safety of the filling process, ozonized water reliably sterilizes the container walls, the cork and the air gap under the cork. The shelf life of water after ozonation increases many times. Combined water treatment with ozone in combination with container rinsing is especially effective.

Oxidation of iron, manganese, hydrogen sulfide

Iron, manganese and hydrogen sulfide are easily oxidized by ozone. This converts the iron into insoluble hydroxide, which is then easily retained in the filters. Manganese is oxidized to permanganate ion, which is easily removed on carbon filters. Hydrogen sulfide, sulfides and hydrosulfides are converted into harmless sulfates. The process of oxidation and the formation of filterable sediments during ozonation occurs on average 250 times faster than during aeration. The use of ozone is especially effective for deferrization of waters containing iron-organic complexes and bacterial forms of iron, manganese and hydrogen sulfide.

Surface water treatment from anthropogenic impurities

Ozonation of pre-clarified water followed by filtration through activated carbon is a reliable way to purify surface water from phenols, oil products, pesticides and heavy metals (oxidative sorption treatment).

Purification and disinfection of water in poultry farms and farms

Ozonation at the poultry farm. The supply of ozone-decontaminated water to drinking bowls for poultry and animals not only helps to reduce the incidence and risk of massive epidemics, but also causes an accelerated weight gain in birds and animals.

Wastewater treatment and disinfection

With the help of ozone, wastewater is discolored.

With the help of ozonation, wastewater can be brought into compliance with the stringent requirements of fishery reservoirs for the content of phenols, oil products and surfactants, as well as microbiological indicators.

Ozonation of water for sanitizing products and equipment

As mentioned above, the shelf life of water ozonized during the filling process increases significantly due to the fact that the product water acquires the properties of a disinfectant solution.

During food processing, bacteria grow on contaminated equipment, which is the source of strong rotting and decay odors. Rinsing the equipment with ozonized water after removing the bulk of the contaminants leads to disinfection of surfaces, a refreshing effect on the room air and an improvement in the general sanitary and hygienic state of production.

Ozonation for sanitization. In the water for sanitizing equipment, in contrast to the ozonation of water before bottling, higher concentrations of ozone are created.

Fish and seafood, poultry carcasses and vegetables can be processed similarly to ozonized water before packaging. The service life of products processed before storage increases, and their appearance after storage does not differ much from fresh products.

5. Safety aspects of the operation of ozone equipment

Ozone gas is toxic and can cause upper respiratory tract burns and poisoning (like any other strong oxidant).

The maximum permissible concentration (MPC) of ozone in the air of the working area is regulated by GOST 12.1.005 "General sanitary and hygienic requirements for the air of the working area", according to which it is 0.1 mg / m3.

The smell of ozone is recorded by a person in concentrations of 0.01-0.02 mg / m3, which is 5-10 times less than the MPC, therefore, the appearance of a weak smell of ozone in the room is not an alarm signal. To ensure reliable monitoring of the ozone content in the production area, gas analyzers must be installed that allow monitoring the ozone concentration and, if the maximum permissible concentration is exceeded, take timely measures to reduce it to a safe level.

Any technological scheme containing ozone equipment must be equipped with a gas separator, with the help of which excess (undissolved) ozone enters the catalytic destructor, where it is decomposed to oxygen. Such a system eliminates the release of ozone into the air of the production room.

Because ozone is the strongest oxidizing agent; all gas lines must be made of ozone-resistant materials such as stainless steel and fluoroplastic.