Dry residue is one of the main criteria for determining the quality of water, which reveals the degree of its mineralization. An ion-s alt residue is used to determine the type of water.
Features of the remainder
As the main ions, due to which it is possible to determine the dry residue, are: sulfates, chlorides, carbonates, nitrates, bicarbonates. There is their division into organic and mineral residues, which differ in boiling points. Solids content refers to the presence of dissolved non-volatile solids in water. There is a special method for calculating it.
Gravimetric calculation method
With its help, the determination of the dry residue in the test sample is carried out. To conduct such a study, it is necessary to filter the sample, to separate it from organic impurities.
Water is used in almost all branches of modern production. For example, in the cosmetic industry it is used as drinking water, as a raw material for the creation of semi-finished products, as a substance for washing industrial containers.
It is with water that organolepticindicators of products manufactured at the enterprise: stability, smell, taste, color. For example, the appearance and taste of syrups are directly related to the minerals contained in the water. If the solids contain sodium chloride, then the water will taste somewhat s alty.
Sanitary standards
There are certain standards that water must meet. If the content of the dry residue does not satisfy them, then it cannot be used. There are special physical and chemical laboratories that are equipped with special measuring instruments.
The mass fraction of dry residue in them is determined according to GOST "Drinking Water" 18164-72. Water is used in production only after it has been fully controlled for compliance with all quality indicators.
If in the course of the research discrepancies are revealed for any indicators, it is necessary to draw up a report on the discrepancy, take the necessary corrective measures.
Methods for determining dry residue
There are several methods to determine the dry residue. GOST allows a procedure with the addition of soda or using s alt. Let's consider both options in more detail.
In the first case, the sample is evaporated using a water bath. First, the container to be used for evaporation is dried until a constant weight is obtained. Next, filtered water is poured into a porcelain container. After the evaporation of the last sample is completed, the cup is dried in an incubator to constant weight at a temperature.
To determine the dry residue, a special formula is used. It connects the mass of the empty container with the dry residue, as well as the amount of water taken for research.
Using this method results in inflated results. This situation is explained by increased hygroscopicity, as well as the hydrolysis of calcium and magnesium chloride, the difficulty of transferring water by calcium and magnesium sulfates.
To eliminate this drawback, pure sodium carbonate is added to the test sample. In the process of adding calcium and magnesium chlorides, they are converted into anhydrous carbonates. To completely remove the water of crystallization, the resulting dry residue is dried at an elevated temperature until a constant mass is obtained in a thermostat.
Soda solution method
This option involves pre-filtration of water using a paper filter. After drying the sample until a constant weight is obtained, the cup must be placed in a water bath. Here the evaporation of water samples taken for analysis is carried out. As soon as the last portion of water is added, a carbon dioxide solution is added with a pipette. Considering that the weight of the soda taken is related to the mass of the dry residue as 2 to 1, mathematical calculations are carried out.
To carry out further evaporation, it is necessary to mix the sample, destroyingwhile forming a crust. A glass rod is used for mixing. Next, wash the stick with distilled water. Then the resulting dry residue with soda in a cup is placed in a thermostat, dried at a temperature of about 150 degrees Celsius until a constant mass is obtained.
The average duration of evaporation is two to five hours. Determine the difference by weight between the capacity of the precipitate formed and the initial weight of the cup and soda. This difference determines the amount of dry residue in the determined amount of water. The dry residue is determined by a formula that relates the mass of an empty container, added soda, and the volume of water selected for analysis.
This analysis from a hygienic point of view lies in the fact that it is possible to technically adjust the analyzed water using filtration systems, while lowering the degree of mineralization.
Conclusion
Taste is considered balanced if the water has a total s alt content of 600 mg per liter. If it contains more than 1 g/l, it is considered undrinkable because it has a bitter-s alty taste.
If you constantly use such water, serious physiological problems may arise in the body. First of all, there is an increase in the motor and secret function of the intestines and stomach, at elevated temperatures the body overheats.
