What is ozone?

Ozone (chemical molecular formula O3), also known as triatomic oxygen, is named for its fishy smell.

The microbial membrane structure is destroyed by oxidation to achieve the purpose of sterilization. Ozone first acts on the cell membrane, destroying the components of the membrane and causing metabolic disorder. Ozone constantly penetrates the membrane, destroying lipoproteins and lipopolysaccharides in the membrane, changing the permeability of cells, leading to cell lysis and death.

The chemical properties of ozone are extremely active, and its free energy produces strong oxidation in an instant, thus sterilization, disinfection and detoxification are carried out. Ozone is easily soluble in water, and has stronger sterilization ability, which is 600-3000 times that of chlorine, and can quickly kill bacteria and viruses. The combination of bacteria and viruses with ozone will change the molecular structure or energy transfer, leading to the death of bacteria and viruses and not forming new germs. Can effectively remove all kinds of bacteria, viruses, odors and toxic gases (formaldehyde, benzene, etc.). ) released by new furniture paint. Proper ozone in the atmosphere is very beneficial to human health.

Similarly, ozone can decompose nicotine produced by smoking, prevent the harm of second-hand smoke to others, decompose the toxicity of pesticides, eliminate the toxicity of sulfur dioxide produced by gas and coal, and eliminate the harm of some radiation to human body.

Ozone is an efficient disinfectant, which has a strong killing effect on bacteria, germs, fungi, mold spores, viruses and other microorganisms. Because ozone is a diffusion gas, there is no dead angle in disinfection, so the disinfection and sterilization effect is good. There are many compounds that kill microorganisms by oxidation to achieve sterilization effect, such as common chlorine, bleaching powder, potassium permanganate and so on. However, these fungicides are not only slower than ozone sterilization, but also harmful to human body in general sterilization. Ozone sterilization is different from ordinary bactericides, because excess ozone can be quickly decomposed into oxygen, so there is no secondary pollution problem.

When the content of ozone in the air is less than one millionth, it is very beneficial to human body. Because a small amount of ozone can * * the central nervous system, accelerate blood circulation, increase active oxygen in blood and activate cells, but high concentration of ozone can make people feel uncomfortable and even cause reversible harm to human body, so the amount of ozone must be controlled. However, ozone has been used for 100 years, so far there has been no death accident caused by ozone poisoning in the world.

Is ozone pure or mixed?

pure substance

What substance can neutralize ozone?

Ozone is oxidizing, and there are many things that can react with it, including too many. As long as it is reducing, it is really bad. For example, because there are too many, ozone such as acetic alcohol is generally used for sterilization.

Why is ozone an air pollutant?

A small amount of ozone has disinfection effect. It can resist ultraviolet rays in the atmosphere. Toxicity and corrosiveness of ozone

Ozone is a harmful gas. When the concentration is 6.25× 10 -6 mol/L(0.3mg/m3), it will cause * * sensation to eyes, nose and throat. When the concentration is (6.25-62.5) ×10-5 mol/L (3-30 mg/m3), headache and local paralysis of respiratory organs occur. When the ozone concentration is 3.125×10-4 ~10-3 mol/l (15 ~ 60 mg/m3), it is harmful to human body. Its toxicity is also related to contact time. For example, long-term exposure to ozone below1.748×10-7 mol/L (4 ppm) will cause permanent heart disorder, but exposure to ozone below 20ppm will not exceed 2 hours, which is not permanent harm to human body. Therefore, the allowable ozone concentration is 4.46×10-9 mol/l (0.1ppm) 8h. Because of the strong smell of ozone, when the concentration is 4.46×10-9 mol/L (0.1ppm), people will feel that,

Ozone is highly oxidizing, and ozonated air has corrosive effect on almost all metals except gold and platinum. Aluminum, zinc and lead will be strongly oxidized when exposed to ozone, while alloys containing chromium and iron are basically not corroded by ozone. Based on this point, ferrochromium alloy (stainless steel) containing 25% Cr is often used in production to manufacture the parts that are in direct contact with ozone in ozone generating equipment and filling equipment.

Ozone also has a strong corrosive effect on nonmetallic materials. Even the fairly stable PVC plastic filter plates used in other places were loosened, cracked and perforated shortly after being used in ozone filling equipment. In ozone generating equipment and metering equipment, ordinary rubber cannot be used as sealing material, and silicone rubber or acid-resistant rubber with strong corrosion resistance must be used.

What is ozone?

Ozone molecule (O3) is composed of three oxygen atoms. It is unstable and has high activity. It is often used as bleach, deodorant and disinfectant for air and drinking water. At low concentrations, ozone is toxic. There is natural low-concentration ozone in the stratosphere of the upper atmosphere of the earth. In this upper atmosphere, ultraviolet rays from the sun break down oxygen molecules (O2) into two independent oxygen atoms. Each oxygen atom combines with an oxygen molecule to form ozone. Stratospheric ozone is called "beneficial" ozone because it can protect the earth's surface from harmful ultraviolet rays. Photo courtesy of the National Institute of Environmental Health (NIEHS)/ National Institutes of Health (NIH) shows the process of ozone generation by nitrogen oxide pollutants: nitrogen dioxide molecules are irradiated by sunlight, releasing oxygen atoms, which attack oxygen molecules to form ozone. Nitric oxide can be combined with ozone to regenerate nitrogen dioxide, and so on. Ozone also appears in the troposphere, the lowest layer of the atmosphere. Tropospheric ozone (usually called "harmful" ozone) is a man-made product, which is caused by air pollution caused by internal combustion engines and power plants. Automobile exhaust and industrial emissions will release a series of nitrogen oxides (nitrogen oxides) and volatile organic compounds (VOC), which are by-products of burning gasoline and coal. Under sunny and high temperature weather conditions in late spring, early summer and early autumn, nitrogen oxides and VOC react with oxygen to generate ozone. High concentrations of ozone usually form in hot afternoons and nights and dissipate in cool nights. Photo provided by NASA: Global seasonal variation of tropospheric ozone: Tropospheric ozone increases in hot summers in the northern and southern hemispheres. The highest concentration of tropospheric ozone can be observed in summer in the northern hemisphere. Ozone pollution is mainly formed in cities and suburbs, and prevailing winds (or cars and trucks heading for the countryside) may also bring it to the countryside. According to research, serious ozone pollution can be detected in rural areas 150 km away from the downwind of urban industrial areas. Photo provided by NIEHS/NIH Ozone pollution can spread from cities to rural areas. Self-made ozone detector You can make ozone test paper to detect and monitor the ozone concentration in your backyard or near your school. What you need: corn starch filter paper (coffee filter paper is also acceptable) and potassium iodide (it can be ordered from scientific and educational equipment suppliers, such as Carolina Bio-supply). The basic steps are as follows: first, water, corn starch and potassium iodide are put together to make paste, and then these paste substances are smeared on filter paper. Then, these filter papers were exposed to air for 8 hours. Ozone in the air will react with potassium iodide, thus changing the color of filter paper. You can read the ozone concentration against the chart on this website. You also need to know the relative humidity, which can be obtained from newspapers, weather forecasts or home weather stations.

What is ozone?

Chinese name ozone

English name ozone

Structure or molecular formula

O atoms form σ bonds with sp2 hybrid orbitals. The molecular shape is v-shaped.

The relative molecular weight or atomic weight of the electronic structural formula is 48.00.

Density Gas density (0℃, g/L) 2.144; Liquid density (-gallbladder 50℃, g/cm3) 1.473.

Melting point (℃) (solid) -25 1

Boiling point (℃) (liquid)-1 12

Character; Role; letter

A thick layer of gaseous ozone is blue and has a special smell, similar to high concentration of chlorine; Liquid ozone is dark blue and solid ozone is purple-black.

use

Used for disinfection of water and ozonation of air, and used as strong oxidant in chemical industry.

Preparation or source

The main ozone manufacturing technologies include electrolysis, nuclear radiation, ultraviolet ray, plasma and corona discharge. Ozone generator is widely used to oxidize air or pure oxygen into ozone, and ultraviolet germicidal lamp decomposes oxygen in the air to form ozone. That is, under the action of oxygen in the air, oxygen molecules are ionized into ozone by using high-energy alternating current.

The reaction between permanganate and strong acid can produce ozone (O3).

Ozone is an allotrope of oxygen. It is a blue gas at room temperature and has a special smell. Molecular formula: O3

What does ozone do?

The ozone content in the atmosphere is only 1%, but there is an ozone layer in the stratosphere 20 to 30 kilometers above the ground, in which the ozone content accounts for 1% of the total air at this height. Although the ozone layer has a very small ozone content, it has a very strong function of absorbing ultraviolet rays, which can absorb the harmful part of sunlight ultraviolet rays (UV-B). Because the ozone layer effectively blocks the invasion of ultraviolet rays from the sun, human beings and all kinds of life on the earth can exist, multiply and develop.

During the period of 1985, British scientists observed the ozone hole over Antarctica and confirmed that it was directly related to chlorine atoms produced by the decomposition of chlorofluorocarbons. The news shocked the whole world. By "1994", the damaged area of ozone layer over Antarctica has reached 24 million square kilometers, the ozone layer over the northern hemisphere is thinner than before, the ozone layer over Europe and North America has decreased by 10%- 15% on average, and even over Siberia has decreased by 35%. Scientists have warned that the ozone layer on the earth has been destroyed to a greater extent than most people think.

Substances that deplete the ozone layer, such as freon, are the chief culprit of ozone layer destruction. Freon was synthesized in the 1920s. Stable chemical properties, non-flammable and non-toxic. Used as refrigerant, foaming agent and cleaning agent, widely used in household appliances, foam plastics, daily chemicals, automobiles, fire fighting equipment and other fields. In the late 1980s, the output of freon reached its peak, reaching 6.5438+0.44 million tons. Before the control of freon, the world had discharged 20 million tons of freon into the atmosphere. Because their average life span in the atmosphere is hundreds of years, most of their emissions remain in the atmosphere, most in the troposphere, and a small part rises to the stratosphere. Freon, which is quite stable in the troposphere, will decompose under the action of strong ultraviolet rays under certain meteorological conditions after rising to the stratosphere, which explains that the released chlorine atoms will have a chain reaction with ozone and destroy ozone molecules continuously. Scientists estimate that a chlorine atom can destroy tens of thousands of ozone molecules.

Substances that deplete the ozone layer, such as freon, are the chief culprit of ozone layer destruction. Freon was synthesized in the 1920s. Stable chemical properties, non-flammable and non-toxic. Used as refrigerant, foaming agent and cleaning agent, widely used in household appliances, foam plastics, daily chemicals, automobiles, fire fighting equipment and other fields. In the late 1980s, the output of freon reached its peak, reaching 6.5438+0.44 million tons. Before the control of freon, the world had discharged 20 million tons of freon into the atmosphere. Because their average life span in the atmosphere is hundreds of years, most of their emissions remain in the atmosphere, most in the troposphere, and a small part rises to the stratosphere. Freon, which is quite stable in the troposphere, will decompose under the action of strong ultraviolet rays under certain meteorological conditions after rising to the stratosphere, which explains that the released chlorine atoms will have a chain reaction with ozone and destroy ozone molecules continuously. Scientists estimate that a chlorine atom can destroy tens of thousands of ozone molecules.

Methods and policies to control ozone layer destruction

In modern economy, substances such as freon are widely used. To completely eliminate them, we must first find alternative substances and technologies such as freon. What needs to be used under special circumstances should also be recycled as much as possible. At present, some major freon manufacturers in the world have participated in the development and research of fluorine-containing substitutes (hydrochlorofluorocarbons and hydrofluoroalkanes, etc.). ) to replace freon and its synthesis method. Freon can be used as foaming agent, refrigerant and cleaning solvent, but such substitutes also destroy the ozone layer or produce greenhouse effect. At the same time, non-Freon substitutes and methods are also being developed, such as water purification technology and ammonia refrigeration technology.

Many countries have adopted a series of policies and measures to promote the development and use of freon substitute substances and technologies and gradually phase out ozone-depleting substances. One is the traditional environmental control measures, such as bans, restrictions, quotas and technical standards, and severely punish those who violate the regulations. EU countries and some countries with economies in transition have widely adopted such measures. One is economic means, such as collecting taxes and fees, subsidizing alternative materials and technological development. The United States has implemented measures such as taxation and tradeable licenses for the production and use of ozone-depleting substances. In addition, many countries, enterprises and non-governmental organizations have also initiated voluntary actions to adopt various environmental labels to encourage producers and consumers to produce and use materials and products that do not contain ozone-depleting substances, among which the green refrigerator logo has always been very popular. ......

What is ozone for?

Protect the earth from direct sunlight through ultraviolet rays.