How do you measure the amount of oxygen in your water? 5

The purpose, the workaround, and the level of accuracy required should be different.

For example, there is an oxygen sensor that can measure directly.

For example, white phosphorus can be burned, oxygen is consumed, and then the water goes up the graduated cylinder down the mouth. Readings can be read.

There are many chemical and physical methods.

Dissolved oxygen meter, which can monitor the dissolved oxygen content. In the environmental engineering company or water equipment company should be sold or can help find the manufacturer, water supply and sewage treatment basically have to test this. The accuracy depends on the level of **, and you can be as accurate as you want.

Iodine and galvanometry can be used to measure the oxygen content in water.

1.Iodometry is a chemical detection method with high measurement accuracy and was the earliest method used to detect dissolved oxygen. The principle is to add manganese sulfate and alkaline potassium iodide to the water sample to generate manganese hydroxide precipitate.

Manganese hydroxide is extremely unstable in nature and quickly dissolves and oxidizes with water to form manganese manganate. The addition of concentrated sulfuric acid causes the combined dissolved oxygen (in the form of manganese manganate) to react with the potassium iodide added to the solution to precipitate iodine, and the precipitated iodine is titrated with a standard solution, and finally the content of dissolved oxygen in the water sample is calculated.

2.galvanometry is an electrochemical detection method, the principle of which is that the dissolved oxygen in water enters the solution through the anode for a reduction reaction to produce electrons, and the electrons flow into the cathode through the measuring electrode and circuit, so that the cuprous salt in the solution near the cathode is reduced to produce copper. When the concentration of dissolved oxygen in the water changes, the amount of dissolved oxygen passing through the solution also changes, thus changing the current flow between the cathode and cathode.

The concentration of dissolved oxygen can be calculated by measuring the change in current. The advantages of galvanometry are that the measurement speed is faster than iodometry, it is easy to operate, there is less interference, and it can be detected automatically and continuously in the field. However, because its oxygen permeable membrane and electrode are relatively easy to age, when the water sample contains algae, sulfide, carbonate, oil and other substances, the oxygen permeable membrane will be blocked or damaged, affecting the accuracy of measurement.

These are two common methods for detecting oxygen content in water.

There is a dissolved oxygen detection instrument, but it is a bit expensive.

The amount of oxygen in water decreases as the temperature increases. Specifically, the higher the temperature, the lower the oxygen content in the water, and the lower the temperature, the higher the oxygen content in the water. For example:

20 liters of water, 100 liters can dissolve 3 liters of oxygen, when the temperature drops to zero, 100 liters of water can dissolve 5 liters of oxygen.

The higher the temperature of the water, the faster the metabolism and respiration rate of fish and aquatic organisms, the more oxygen content is required than usual, and the oxygen content in the water will naturally decrease. If there is less oxygen in the water, the activity of the fish will be weakened, and the fish will directly surface to breathe the oxygen in the atmosphere in order to cope with the low amount of oxygen, which is often called "floating head".

The amount of dissolved oxygen is related to the depth of the water. Because oxygen is infiltrated from the atmosphere through the surface of the water, the slower the penetration rate is, and the internal pressure of the water is not lower than the atmospheric pressure, so the oxygen content that penetrates into the deep layer is very small, which is why the principle that the water is too deep when we raise fish is not beneficial, and it is better to have a water depth of 2 or 3 meters, because the oxygen content in the water at this depth is very high.

The amount of oxygen in the water is related to the area of the water. The larger the surface area of the water, the higher the oxygen content, and the smaller the surface area of the water, the lower the oxygen content. Therefore, under the same conditions, the probability of fish in a small water surface "turning over (pan) pond" is much greater, for example, a large water surface like a lake will not have a "flipping (pan) pond".

Fluctuations in the water surface cause changes in the oxygen content of the water. For example, when the wind blows, the waves on the surface of the water are in contact with the air, and the undulating wave area is larger than the surface area of the normal still water. Therefore, when the wind blows, the oxygen content in the water is higher than usual.

Therefore, people say that "the wind blows the water, and the water moves the fish" refers to the situation at this time.

In fact, the aerator dissolves the air (oxygen) into the water according to the principle that the fluidity of the water and the contact with the air will increase the oxygen content in the water"Waves"and then absorbed into the water body.

The dissolved oxygen content in the water is different at different temperatures and pressures, such as 25 degrees Celsius and 1013 hPa, the dissolved oxygen saturation in the water is 1013 hPa, and the specific value can be determined by the dissolved oxygen meter.

Generally, the dissolved air in water contains 2vol, and the volume content of oxygen in water is 1 5 of air, so the dissolved oxygen in water is the volume content. There is not much difference between seawater and freshwater, and you can know the oxygen content of the water by testing the chemical oxygen demand, which is the COD.

It's about temperature. When the temperature is high, it is difficult for oxygen to dissolve into the water, and the oxygen content is low; When the temperature is low, oxygen is easily dissolved into the water, and the oxygen content is high. In general, it is normal for a litre of water to contain more than 5 mg of oxygen.

The amount of saturated oxygen in <> water depends on the temperature and is generally at 20 degrees Celsius.

Under the conditions, the saturated dissolved oxygen concentration is about 8 9mg l, and the salinity also has an effect on the saturated dissolved oxygen concentration in the water. In natural water, oxygen concentrations are generally less than saturated dissolved oxygen concentrations, due to the presence of organic matter in the water (especially polluted water) that microorganisms or bacteria can use to grow and consume some of the oxygen in the water.

Oxygen, chemical formula O?, relative molecular mass.

There is no world wax auspicious color, odorless gas, oxygen element.

The most common elemental form. Melting point, boiling point -183 . Not easily soluble in water, about 30ml of oxygen is dissolved in 1L of water.

In the air, oxygen accounts for about 21%. Liquid oxygen is a sky-blue liquid. Oxygenation is a blue crystal.

It is not very active at room temperature, and it is not easy to interact with many substances. However, at high temperatures, it is very active and can be directly combined with a variety of elements, which is related to the electronegativity of oxygen atoms.

Second only to local jujube fluoride.

1. Oxygen gravimetric method.

Oxygen gravimetry is a classic method used to measure the amount of dissolved oxygen in water. This method uses an oxygen concentration meter to measure the amount of dissolved oxygen in the water at room temperature to calculate the mass of oxygen in the water. The accuracy of the measurement results of the oxygen gravimetric method is high, but the operation process is cumbersome, and the water samples need to be collected and measured in the laboratory, and the measurement results need to be calculated through the data.

Second, the water-weight ratio method.

The water-gravimetric method is a method for quickly measuring the amount of dissolved oxygen in water in the field. This method calculates the mass of dissolved hydrogen in water by the ratio of dissolved oxygen dissolved in a container per unit volume of water to the volume (milliliters) occupied by the container. The water-to-weight ratio method has a high degree of confidence in the measurement results, which is especially suitable for quickly understanding the dissolved oxygen content in the water body in the field investigation.

However, the operation process is cumbersome, requiring plexiglass bottles, high-temperature autoclaves and other equipment, and there are potential safety hazards in high-temperature and high-pressure operation.

3. Dissolved oxygen meter method.

The dissolved oxygen meter method is a method that uses instruments to quickly measure the amount of dissolved oxygen in water in situ. This method uses a method for determining the concentration of saturated dissolved oxygen in dissolved gases of different concentrations. The dissolved oxygen meter method is portable and can quickly measure the content of dissolved oxygen in water, but the electrode needs to be calibrated regularly, and the electrode is easily damaged by improper operation during the calibration process.

4. Ion exchange method.

Ion exchange is a method of measuring the amount of dissolved oxygen in water in a laboratory. In this method, the water sample was added to organic solvent, boiled at 60 90 for 5 min, filtered, washed, dried or dried after being taken out and weighed, and the content of dissolved oxygen in the water was calculated according to the following method. The operation process of ion exchange method is cumbersome, requiring equipment such as plexiglass bottles and high-temperature autoclaves, and there are potential safety hazards in high-temperature and high-pressure operation.

5. Electrolysis.

Electrolysis is also a method of measuring the amount of dissolved oxygen in water in the laboratory. There are three types of electrolyzers: V-type, U-type and D-type, of which the V-type and U-type electrolyzers are called polarographic method in the previous version, and the D-type electrolyzer is called the Coulomb method. The principle is to reduce dissolved oxygen in water through an electrolytic system with silver as the anode and copper as the cathode in the electrolyzer.

The measurement results of electrolysis are greatly affected by CO2 and other substances, and require plexiglass bottles, high-temperature autoclaves and other equipment, and there are potential safety hazards in high-temperature and high-pressure operation.

In practical applications, different measurement methods and instruments have their own advantages and disadvantages and scope of application. Therefore, when choosing a method to measure dissolved oxygen content in water, it is necessary to choose the appropriate method and instrument according to the actual situation to improve the accuracy and reliability of the measurement results. At the same time, it is also necessary to pay attention to safety issues, especially in the field operation, it is necessary to follow the corresponding safety regulations to avoid safety accidents caused by improper operation.

A variety of methods can be used to determine the oxygen content in a water sample. Here are a few common ways to feast:

1. Electrochemical method (dissolved oxygen electrode method).

This is a commonly used method for determining the amount of dissolved oxygen in water samples. This method uses a special dissolved oxygen electrode to measure the concentration of dissolved oxygen based on the electrochemical reaction of oxygen that occurs on the surface of the electrode.

Advantages: The electrode method is simple to operate, the measurement results are accurate, and the content of dissolved oxygen in water samples can be monitored in real time.

Disadvantages: This method requires the use of special electrode equipment, and the performance and stability of the electrode may be affected, so attention needs to be paid to calibration and maintenance.

2. Optical method (spectroscopy).

Spectroscopy determines the amount of dissolved oxygen by measuring the absorption or fluorescence of dissolved oxygen in a water sample to a specific wavelength of light. These methods include ultraviolet-visible spectroscopy and fluorescence spectroscopy, among others.

Advantages: The spectroscopy method is simple to operate, the measurement results are accurate, and non-destructive measurements can be carried out in the morning.

Disadvantages: Requires specialized spectroscopic instruments, which may be interfered with by other substances in the water sample.

3. Chemical method (ferrous sulfate method).

In this method, ferrous sulfate reacts with dissolved oxygen in a water sample to produce iron oxide, and the amount of dissolved oxygen is determined by titration measurement of ferrous ions in the solution before and after the reaction.

Advantages: The ferrous sulfate method is simple to operate, low cost, and suitable for the determination of a large number of samples.

Disadvantages: This method requires the use of toxic chemical reagents and titration operations, and is susceptible to environmental and human manipulation.

In addition to the above methods, there are other methods that can be used to determine the oxygen content in water samples, such as redox potential method, oxygen sensor method, etc. When choosing the right measurement method, factors such as measurement accuracy, equipment requirements, number of samples, and time required need to be considered. In addition, calibration and quality control are key factors in ensuring the accuracy of measurement results.

It is recommended to refer to the relevant standard methods and laboratory practice guidelines when performing oxygen measurements to ensure accurate determination of oxygen content in water samples.

Potassium dichromate method:

cod(o2,mg/l)=[v0-v1)*c*8g/mol*1000]/v

C--The concentration of ammonium ferrous sulfate standard solution, mol LV0 - the volume of ferrous sulfate as a closed ammonium standard solution when titrating blank, ML1 - the volume of ammonium ferrous sulfate standard lead-containing quasi-solution when titrating water samples, MLV - the volume of pure old fission of water samples, ml

8g mol - oxygen (1 2o) molar mass.

The amount of oxygen in the water can vary depending on the specific conditions and environment. Here are some common ranges of oxygen levels in water:

1.Natural water bodies (e.g., lakes, rivers, oceans): Typically, the concentration of dissolved oxygen in natural water bodies can vary from 0 to 20 milligrams of milligrams (mg L), depending on factors such as water temperature, depth, water flow, and slag from biological activity.

2.Drinking water: In order to ensure the quality and safety of drinking water, it is generally required that the concentration of dissolved oxygen in the water is between 5 and 8 milliliters. This helps to maintain the health of the organisms in the water and keep the water fresh.

It is important to note that the amount of dissolved oxygen in the water can be affected by environmental conditions such as temperature, pressure, and biological activity in the water. In addition, factors such as anthropogenic pollution, eutrophication of water bodies, and water pollution may also affect the dissolved oxygen content in water.

If you are interested in the dissolved oxygen content of a particular body of water, it is best to obtain accurate and specific information through water quality monitoring or data from relevant professional bodies.