What Kind Of Water Is More Suitable For Rotary Evaporator Heating

The water bath of rotary evaporator has been used for a long time, and the following conditions may appear on the surface:

• Scaling: The water in the water bath will form scale if heated for a long time. The adhesion of scale to the boiler wall not only affects the heating effect, but also may affect the purity of the solution. If the water in the water bath pot contains minerals such as calcium and magnesium, long-term heating may form hard scale and attach to the pot wall.
• Corrosion: If the water in the water bath pot contains impurities or acidic substances, long-term heating may cause corrosion to the pot wall.
• Aging: If the water bath pot is used for a long time, its material may age, resulting in the thinning of the pot wall or cracks.

          

The type of water NOT suitable for rotary evaporator water bath heating

 

 

De-ionized water

Water that removes cations and anions from water by ion exchange technology. There is almost no solute in deionized water, including minerals, salts and organic matter. Although the purity of deionized water is high, it still contains some trace impurities and dissolved gases. If deionized water is used for heating, it may corrode the material of the water bath pot or affect the heating effect.

 

Distilled water/desalted water

 

Distilled water: Pure water produced by distillation. The distillation process involves heating water to boiling, and then condensing the generated water vapor back to liquid water. This process can remove most solutes, including microorganisms, minerals and organic matter.

Desalinated water: Fresh water obtained by removing salt from a salty water source (such as seawater or salt water). Desalination process can adopt reverse osmosis, electrodialysis, evaporation and other methods. Although the purity of desalted water is high, it still contains some trace impurities and dissolved gases. If desalted water is used for heating, it may also cause corrosion to the material of the water bath pot or affect the heating effect.

Distilled water and desalted water may still contain a small amount of oxygen, carbon dioxide and other gases, as well as a small amount of nonionic substances. These components may promote metal corrosion during heating, especially for some metal materials, such as iron and copper. Therefore, under the action of long-term heating, distilled water may cause some corrosion to the materials of equipment such as water bath pots. In addition, trace impurities and gases in distilled water may also affect the heating effect. Trace impurities and gases may affect the efficiency of heat transfer, resulting in uneven temperature distribution or slow heat transfer speed during heating, thus affecting the accuracy of experimental results.

Tap water

 

The treated drinking water is supplied to families and enterprises. Tap water usually comes from water sources (such as rivers, lakes or groundwater) and goes through a multi-step treatment process (such as filtration, disinfection and pH adjustment). Tap water may contain certain minerals, microorganisms and chemicals, which may be different according to the water quality in different regions.

Although many impurities are removed from tap water during treatment, it may still contain a certain amount of hard ions such as calcium and magnesium ions, which is easy to form hard scale when heated. Long-term use will lead to the formation of thick hard scale on the surface of the water bath pot, which will affect the heating effect and the purity of the solution.

Hard scale is not easy to conduct heat, which will reduce the heat transfer ability of water bath pot and lead to uneven heating, thus affecting the accuracy of experimental results. In addition, hard scale will increase the heat capacity of the water bath pot, make the heating time longer and the heating efficiency lower.

Hard scale contains a large number of calcium and magnesium ions, which will react with the chemicals in the experimental substances to form water-insoluble precipitates, reducing the purity of the experimental solution. In some cases, there may be microorganisms and organic substances in the hard scale, which will also affect the accuracy of the experimental results.

 

In order to protect the water bath and ensure the accuracy of the experimental results, it is very important to choose the properly treated pure water for the laboratory.

 

Filtration treatment: suspended particles, microorganisms and most dissolved organic matter in water can be removed by filtration. Commonly used filtration methods include the use of microporous filters, paper filter paper or activated carbon. Filtration treatment can reduce the existence of impurities, prevent equipment from blocking and reduce the generation of deposits, thus prolonging the service life of equipment.

Deionizing treatment: Deionized water is a treatment method to improve the purity of water by removing ions and soluble inorganic salts from water. Deionizing treatment usually includes ion exchange technology, which uses ion exchange resin to remove cations and anions in water. Deionized water has high purity, which can reduce the corrosion to equipment and reduce the possible adverse reactions in the experiment.

Distillation treatment: Distillation is a treatment method of heating water to boiling and collecting steam after condensation. Most impurities in water can be removed by distillation, including dissolved solids, organic matter and most ions. Distilled water has high purity and is suitable for experiments with high water quality requirements. The use of distilled water can reduce the risk of equipment corrosion and provide more accurate experimental results.

 

The scale on the water bath of rotovap is formed by the precipitation and precipitation of soluble salts in water during heating. If it is not cleaned in time, it will affect the service life of the equipment and the accuracy of experimental results.

Method for removing scale on water bath pot of chemical rotary evaporator

• Acetic acid cleaning method: Mix acetic acid and water according to the ratio of 1:1, pour the mixed solution into a water bath, heat it for 10-15 minutes, and then rinse it with clear water. This method can effectively remove the scale, and it is easy to operate and low in cost, which is suitable for general scale cleaning.
• Hydrochloric acid cleaning method: Mix hydrochloric acid and water according to the ratio of 1:5, pour the mixed solution into a water bath and heat it until it boils, then turn off the fire source, let it cool naturally, and then rinse it with clear water. This method can completely remove the scale, but due to the strong corrosiveness of hydrochloric acid, it is necessary to pay attention to safe operation.
• Citric acid cleaning method: Mix citric acid and water at a ratio of 1:3, pour the mixed solution into a water bath and heat it to boiling, then turn off the fire source, let it cool naturally, and then rinse it with clear water. This method can remove the scale, and it is less corrosive to the equipment, but care should be taken not to overuse citric acid to avoid affecting the experiment.

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