The phrase "ozone layer", which became famous in the 70s. the last century, has long been set on edge. At the same time, few people really understand what this concept means and why the destruction of the ozone layer is dangerous. An even bigger mystery for many is the structure of the ozone molecule, and yet it is directly related to the problems of the ozone layer. Let's learn 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, ozone occurs in nature 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 does an ozone molecule look like?

Ozone got its nickname "active oxygen" because of its resemblance to oxygen. So the main acting chemical element in these substances is oxygen (O). However, if an 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 because of this that after rain it is so easy to breathe: ozone oxidizes harmful substances contained in the air, and it is purified.

The model of the ozone molecule (consisting of 3 oxygen atoms) looks a bit like an image of an angle, and its size is 117°. This molecule has no unpaired electrons and is therefore diamagnetic. In addition, it has polarity, although it consists of atoms of one element.

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

Due to the instability of ozone, it cannot be harvested, stored, or transported like other substances. For this reason, its production is more expensive than other substances.

At the same time, the high activity of O 3 molecules allows this substance to be the strongest oxidizing agent, 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, in order for the reverse process to occur (the formation of O 3 from O 2), it is necessary to spend it no less.

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

O3 properties

Whichever 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 from each other.

O 3 is able to oxidize almost all metals and non-metals (except gold, iridium and platinum).

Also, this substance can participate in the combustion reaction, but this requires more heat than for O 2 .

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

How is the ozone molecule 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 in which O 2 is located, whose atoms serve as " building material» for ozone.

Sometimes pure oxygen or ordinary air is run into these apparatuses. 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 extracted 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 named Sheinbein, 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 a lot of research, the scientist described the substance he discovered and gave it the name "ozone" in honor of Greek word"smell".

The ability to kill fungi and bacteria, as well as 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 made it possible to 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 apparatus that was used for the first time in France in 2 years at treatment facilities for drinking water. Since the beginning of the XX century. Europe is beginning 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 drinking water purification using ozone were equipped in the country.

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

Applications of ozone

In addition to water purification, O 3 has a number of other applications.

• Ozone is used as a bleach in the manufacture of paper and textiles.
• Active oxygen is used to disinfect wines, as well as to accelerate the aging process of cognacs.
• With the help of O 3, various vegetable oils are refined.
• Very often, this substance is used to process perishable products, such as meat, eggs, fruits and vegetables. This procedure does not leave chemical traces, as with the use of chlorine or formaldehyde, and products can be stored 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 wound disinfection.
• IN last years portable home appliances for filtering air and water using ozone are gaining immense popularity.

Ozone layer - what is it?

At a distance of 15-35 km above the Earth's surface 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 an amount of a substance come from if its molecules are unstable? It is not difficult to answer this question if we recall the model of the ozone molecule and the method of its formation. So, oxygen, consisting of 2 oxygen molecules, getting into the stratosphere, is heated there by the sun's rays. This energy is enough 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 radiation.

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 have a destructive effect on living organisms.

Having considered the features and structure of ozone molecules, we can conclude that this substance, although dangerous, is very useful for mankind if it is used correctly.

Introduction

Ozone is a simple substance, an allotropic modification of oxygen. Unlike oxygen, the ozone molecule consists of three atoms. Under normal conditions, it is a sharp-smelling explosive gas of blue color, and has strong oxidizing properties.

Ozone is a permanent component of the earth's atmosphere and plays an essential role in sustaining life on it. In the surface layers of the earth's atmosphere, the concentration of ozone increases sharply. The overall state of ozone in the atmosphere is variable and fluctuates with the seasons. Atmospheric ozone plays a key role in sustaining life on earth. It protects the Earth from the damaging effects of a certain role of solar radiation, thereby contributing to the preservation of life on the planet.

Thus, it is necessary to find out what effects ozone can have on biological tissues.

General properties of ozone

Ozone is an allotropic modification of oxygen consisting of triatomic O 3 molecules. Its molecule is diamagnetic and has an angular shape. The bond in the molecule is delocalized, three-center.

Rice. 1 Structure of ozone

Both o-o connections in an ozone molecule have the same length of 1.272 angstroms. The angle between the bonds is 116.78°. Central oxygen atom sp²-hybridized, has one lone pair of electrons. The molecule is polar, the dipole moment is 0.5337 D.

The nature of the chemical bonds in ozone determines its instability (after a certain time, ozone spontaneously turns into oxygen: 2O3 -> 3O2) and high oxidizing ability (ozone is capable of a number of reactions in which molecular oxygen does not enter). The oxidizing effect of ozone on organic substances is associated with the formation of radicals: RH + O3 RO2 + OH

These radicals initiate radical chain reactions with bioorganic molecules (lipids, proteins, nucleic acids), which leads to cell death. The use of ozone to sterilize drinking water is based on its ability to kill germs. Ozone is not indifferent to higher organisms either. Prolonged exposure to an atmosphere containing ozone (for example, physiotherapy and quartz irradiation rooms) can cause severe impairment. nervous system. Therefore, ozone in large doses is a toxic gas. Its maximum permissible concentration in the air of the working area is 0.0001 mg / liter. Ozone pollution of the air occurs during the ozonation of water, due to its low solubility.

Discovery history.

Ozone was first discovered in 1785 by the Dutch physicist M. van Marum by the characteristic odor and oxidizing properties that air acquires after electric sparks are passed through it, as well as by the ability to act on mercury at ordinary temperature, as a result of which it loses its luster and begins to stick to glass . However, it was not described as a new substance; van Marum believed that a special "electric matter" was formed.

Term ozone was proposed by the German chemist X. F. Schönbein in 1840 for its odor, entered the dictionaries in late XIX century. Many sources give priority to the discovery of ozone in 1839 to him. In 1840 Schonbein showed the ability of ozone to displace iodine from potassium iodide:

The fact of a decrease in the volume of gas during the conversion of oxygen into ozone was experimentally proved by Andrews and Tet using a glass tube with a pressure gauge filled with pure oxygen, with platinum wires soldered into it to produce an electric discharge.

physical properties.

Ozone is a blue gas that can be seen when viewed through a significant layer, up to 1 meter thick, of ozonized oxygen. In the solid state, ozone is black with a violet tint. Liquid ozone has a deep blue color; transparent in a layer not exceeding 2 mm. thickness; pretty durable.

Properties:

§ Molecular weight - 48 a.m.u.

§ Gas density at normal conditions- 2.1445 g/dm³. Relative density of gas for oxygen 1.5; by air - 1.62

§ Liquid density at −183 °C - 1.71 g/cm³

§ Boiling point - -111.9 °C. (liquid ozone has 106 °C.)

§ Melting point - -197.2 ± 0.2 ° C (usually given mp -251.4 ° C is erroneous, since its determination did not take into account the great ability of ozone to supercool).

§ Solubility in water at 0 °C - 0.394 kg / m³ (0.494 l / kg), it is 10 times higher compared to oxygen.

§ In the gaseous state, ozone is diamagnetic, in the liquid state it is weakly paramagnetic.

§ The smell is sharp, specific "metallic" (according to Mendeleev - "the smell of crayfish"). At high concentrations, it smells like chlorine. The smell is noticeable even at a dilution of 1: 100,000.

Chemical properties.

Chemical properties ozone is determined by its great ability to oxidize.

The O 3 molecule is unstable and, at sufficient concentrations in air under normal conditions, spontaneously turns into O 2 in a few tens of minutes with the release of heat. An increase in temperature and a decrease in pressure increase the rate of transition to the diatomic state. At high concentrations, the transition can be explosive.

Properties:

§ Oxidation of metals

§ Oxidation of non-metals

§ Interaction with oxides

§ Burning

§ Formation of ozonides

Methods for obtaining ozone

Ozone is formed in many processes accompanied by the release of atomic oxygen, for example, during the decomposition of peroxides, the oxidation of phosphorus, etc. In industry, it is obtained from air or oxygen in ozonizers by the action of an electric discharge. O3 liquefies more easily than O2 and is therefore easy to separate. Ozone for ozone therapy in medicine is obtained only from pure oxygen. When air is irradiated with hard ultraviolet radiation, ozone is formed. The same process takes place in the upper layers of the atmosphere, where the ozone layer is formed and maintained under the influence of solar radiation.

Ozone is a word of Greek origin, which in translation means “odorous”. What is ozone? At its core, O3 ozone is a blue gas with a characteristic odor that is associated with the smell of air after a thunderstorm. Especially felt near sources electric current.

History of ozone discovery by scientists

What is ozone? How was it opened? In 1785, the Dutch physicist Martin van Marum carried out several experiments aimed at studying the effect of electric current on oxygen. According to their results, the scientist investigated the appearance of a specific "electric matter". Continuing to work in this direction, in 1850 he managed to determine the ability of ozone to interact with organic compounds and its property as an oxidizing agent.

The disinfectant properties of ozone were first used in 1898 in France. In the town of Bon Voyage, a plant was built that disinfected and disinfected water from the Vasyubi River. In Russia, the first ozonation plant was launched in St. Petersburg in 1911.

Ozone was widely used during the First World War as an antiseptic. The ozone-oxygen mixture was used to treat intestinal diseases, pneumonia, hepatitis, and was practiced for infectious lesions after surgery. Especially active in ozonation began in 1980, the impetus for this was the appearance on the market of reliable and energy-saving. Currently, ozone is used to purify about 95% of water in the United States and throughout Europe.

Ozone generation technology

What is ozone? How is it formed? In the natural environment, ozone is found in the Earth's atmosphere at an altitude of 25 km. In fact, it is a gas that is formed as a result of ultraviolet radiation from the Sun. On the surface, it forms a layer 19-35 km thick, which protects the Earth from the penetration of solar radiation. According to the interpretation of chemists, ozone is active oxygen (a compound of three oxygen atoms). In the gaseous state, it is blue, in the liquid state it has an indigo hue, and in the solid state it is dark blue crystals. O3 is its molecular formula.

What is the harm of ozone? It belongs to the highest hazard class - it is a very poisonous gas, the toxicity of which is equated to the category of chemical warfare agents. The reason for its appearance is electrical discharges in the atmosphere (3O2 = 2O3). In nature, you can feel it after strong lightning flashes. Ozone interacts well with other compounds and is considered one of the reasons why it is used to kill bacteria, viruses, microorganisms, to purify water and air.

The negative impact of ozone

What does ozone do? A characteristic feature of this gas is the ability to quickly interact with other substances. If in nature there is an excess of normative indicators, then as a result of its interaction with human tissues, hazardous substances and diseases can occur. Ozone is a powerful oxidizing agent, upon interaction with which the following are rapidly destroyed:

• natural rubber;
• metals other than gold, platinum and iridium;
• Appliances;
• electronics.

At high concentrations of ozone in the air, a deterioration in human health and well-being occurs, in particular:

• the mucous membrane of the eyes is irritated;
• the functioning of the respiratory system is disrupted, which will lead to paralysis of the lungs;
• there is a general fatigue of the body;
• headaches appear;
• possible allergic reactions;
• burning in the throat and nausea;
• going on Negative influence to the nervous system.

Useful properties of ozone

Does ozone purify the air? Yes, despite its gas is very beneficial for humans. In small concentrations, it is noted for its excellent disinfectant and deodorizing properties. In particular, it has a detrimental effect on harmful microorganisms and causes to be destroyed:

• viruses;
• various types of microbes;
• bacteria;
• fungi;
• microorganisms.

Most often, ozone is used during an influenza epidemic and outbreaks of dangerous infectious diseases. With its help, water is purified from various kinds of impurities and iron compounds, while enriching it with oxygen and minerals.

Interesting information about ozone, its scope

Excellent disinfectant properties and no side effects led to the emergence of demand for ozone and its widespread use in various sectors of the economy. Today, ozone is successfully used for:

• meet the needs of the pharmaceutical industry;
• water purification in aquariums and fish farms;
• pool disinfection;
• medical purposes;
• cosmetic procedures.

In the medical industry, ozonation is practiced for ulcers, burns, eczema, varicose veins, wounds and dermatological diseases. In cosmetology, ozone is used to combat skin aging, cellulite and excess weight.

The effect of ozone on the vital activity of living beings

What is ozone? How does it affect life on Earth? According to scientists, 10% of ozone is in the troposphere. This ozone is an integral component of smog and acts as a pollutant. It adversely affects the respiratory organs of people, animals and slows down the growth of plants. However, its amount is very small to significantly harm health. A significant part of the harmful ozone in the composition of smog is the products of the functioning of cars and power plants.

Much more ozone (about 90%) is in the stratosphere. This one absorbs biologically harmful ultraviolet radiation from the Sun, thereby protecting people, flora and fauna from negative consequences.

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

In 1840, the German scientist Sheinbein, 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 Sheinbein because of its characteristic smell, and it comes from the Greek word "osien", which means "smell".

In 1857, with the help of the "perfect tube of magnetic induction" created by Werner von Siemens, the first technical ozone installation was built. In 1901, Siemens built the first hydroelectric station with an ozone generator 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 Maur (France). Already in 1907, the first water ozonation plant was built in the city of Bon Voyage (France), for the needs of the city of Nice. In 1911, a drinking water ozonation station was put into operation in St. Petersburg (currently it is not operating). In 1916, there were already 49 installations for the ozonation of drinking water.

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 - ozonizers (ozone generators).

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

2. Ozone and its properties

Formation mechanism and molecular formula of ozone

It is known that the oxygen molecule consists of 2 atoms: O2. Under certain conditions, an oxygen molecule can dissociate, i.e. break down into 2 separate atoms. In nature, these conditions are created during a thunderstorm during discharges of atmospheric electricity, and in the upper atmosphere, under the influence of ultraviolet radiation from the sun (the Earth's ozone layer). Mechanism of formation and molecular formula of ozone. However, the oxygen atom cannot exist separately and tends to regroup. In the course of such a 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 = 1.28 A, q = 116.5°).

It should be noted that the bond of the third atom in the ozone molecule is relatively weak, 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 0°C and pressure 0.1 MPa 2.143 kg/m3. Getting ozone

In low 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. So, 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 has the property of self-decay. It is because of this property that ozone is a strong oxidizing agent and an exceptionally effective disinfectant.

Oxidation potential of ozone

A measure of the effectiveness of an oxidizer is its electrochemical (oxidation) potential, expressed in volts. Below are the values ​​of the electrochemical potential of various oxidizing agents in comparison with ozone:

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

Onsite application

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

Solubility of ozone in water

In accordance with Henry's law, the concentration of ozone in water increases with an increase in the concentration of ozone in the gas phase mixed with water. In addition, the higher the water temperature, the lower the concentration of ozone in the water.

The solubility of ozone in water is higher than that of oxygen, but lower than that of chlorine by 12 times. If we consider 100% ozone, then its limiting concentration in water is 570 mg/l at a water temperature of 20C. The concentration of ozone in the gas at the output 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-decomposition of ozone in water and air

The rate of ozone decomposition in air or water is estimated using the half-life, i.e. the time it takes for the ozone concentration to halve.

Self-decomposition of ozone in water (pH 7)

Self-decomposition of ozone in the air

It can be seen from the tables that aqueous solutions of ozone are much less stable than gaseous ozone. Data on ozone decay in water are given for clean water containing no dissolved or suspended impurities. The rate of ozone decay in water increases many times in the following cases:

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

3. Methods for producing ozone

Currently, 2 methods of generating ozone are widely used:

*UV irradiation

* under the influence of a quiet (i.e. diffuse, without the formation of sparks) corona type discharge

1. UV irradiation

Ozone can form in the vicinity of UV lamps, but only in small concentrations (0.1% by weight).

2. Corona discharge

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

The pure oxygen entering the ozone generator can be replaced by ambient air containing a large percentage 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. The use of ozone for water purification and disinfection

Water disinfection

Ozone destroys all known microorganisms: bacteria, viruses, protozoa, their spores, cysts, etc.; while ozone is 51% stronger than chlorine and acts 15-20 times faster. The polio virus dies at an ozone concentration of 0.45 mg / l after 2 minutes, and from chlorine - only 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 (BL*) when using various disinfectants

*The higher the BLC, the more powerful the disinfectant

Comparison of disinfectants

Water deodorization

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.

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

Oxidation of iron, manganese, hydrogen sulfide

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

Purification of surface waters 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 (oxidation-sorption purification).

Purification and disinfection of water in poultry farms and farms

Ozonation at a poultry farm. The supply of water disinfected with ozone to drinkers for poultry and animals not only helps to reduce the incidence and risk of mass epidemics, but also causes an accelerated weight gain in birds and animals.

Wastewater treatment and disinfection

Ozone bleaches wastewater.

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

Water ozonation for food and equipment sanitization

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

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

Ozonation for sanitation. Equipment sanitization water, in contrast to ozonation of water before bottling, creates higher concentrations of ozone.

Similarly, fish and seafood, poultry carcasses and vegetables can be treated with ozonized water before packaging. The service life of processed products before storage increases, and their appearance after storage differs little from fresh products.

5. Safety aspects in the operation of ozone equipment

Gaseous ozone is toxic and can cause upper respiratory tract burns and poisoning (like any other strong oxidizing agent).

The maximum permissible concentration (MAC) 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 fixed by a person in concentrations of 0.01-0.02 mg/m3, which is 5-10 times less than the MPC, so the appearance of a slight smell of ozone in the room is not an alarm signal. To ensure reliable control of the ozone content in the production room, gas analyzers should be installed that allow monitoring the ozone concentration and, if the MPC 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, through which excess (undissolved) ozone enters the catalytic destructor, where it decomposes to oxygen. Such a system eliminates the flow of ozone into the air of the production room.

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

Ozone was first obtained and studied by Shenbein 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 electrical discharge is passed through air or oxygen (the fresh smell after a thunderstorm is due to the presence of small amounts of ozone in the atmosphere), the oxidation of wet phosphorus, the action of radium rays, ultraviolet or cathode rays on oxygen in the air, the decomposition of hydrogen peroxide, the electrolysis of sulfuric acid (etc. .
oxygen-containing acids), the effect of fluorine on water, etc. The content in the earth's atmosphere is negligible; layers of air 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 region) Levy found 0-3.7 mg, at an altitude of 3.000 m—9,4 mg. ozone per 100 m cube air. Ozone generators are used in engineering and laboratories to produce ozone. For ozonation, oxygen or air is passed between two electrodes connected to a high voltage current source.
Ozone in its pure form is released from a mixture of ozone with oxygen when cooled with liquid air. Ozone is easily decomposed, 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 sulfurous metals into sulfate salts, decolorizes organic dyes, etc. Ozone destroys rubber tubes. Ether, alcohol, lighting gas, cotton wool ignite when in contact with highly ozonized oxygen. Under the action of ozone on unsaturated organic compounds, addition products of ozonides are formed. Ozone is used for water sterilization, for deodorization - the destruction of bad smell, in preparative organic practice.

Physical properties

Chemical properties and preparation methods

List of used literature

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