Sodium Metabisulfite with the chemical formula (Na2S2O5) is a white compound of hydrogen, sulfur, and oxygen that is inorganic and is known to be one of the strongest chemicals in removing chlorine from water. This inorganic combination of antioxidants and disinfectants is very strong and is used not only in water treatment and wastewater but also in food production industries such as paper and other industries.
Physical and Chemical Properties:
Sodium Metabisulfite often appears as white crystalline powders. This chemical compound has no hydrogen carbon bonds and is therefore called an inorganic compound. This compound has a high solubility in water with increasing temperature and is highly soluble in glycerol. In addition, it is slightly soluble in ethanol. The most important feature of this product can be called its high solubility in water, which makes it possible to keep this substance in the solution as normal.
|Chemical formula||Na2S2O5, Na-O-(S=O)-O-(S=O)-O-Na|
|Appearance||White to yellow powder|
|odor||the odor of sulfur dioxide|
|PH (10 % aqueous solution)||4.0-5.5|
|Melting point (° C)||170 (338 °F; 443 K)|
|Boiling point (° C)||decomposes|
|Water Solubility (g/100 mL at 0,20,100° C)||45.1|
|Solubility||Very soluble in glycerol|
Slightly soluble in ethanol
|color||White to yellowish|
|form||hexagonal crystals or powder|
|Chemical Structure Depiction|
Formula and Structure of Sodium Metabisulfite:
Sodium metabisulfite has the chemical formula Na2S2O5. Sodium has a positive charge while metabisulfite (S2O52) has a negative charge. Due to the presence of two S atoms, it is called metabolite sulfite.
There are various methods for producing sodium metabisulfite. This compound can be produced by evaporating a solution of sodium sulfite saturated with sulfur dioxide gas.
Sodium metabisulfite in combination with acids releases sulfur dioxide:
Na2S2O5 + 2 HCl → 2 NaCl + H2O + 2SO2
At high temperatures this compound releases sulfur dioxide which remains sodium sulfite:
Na2S2O5 → Na2SO3 + SO2
The newest method of producing metabolic sodium sulfite in the world is the use of the wet gas process.
Applications and Uses of Sodium Metabisulfite:
Sodium metabisulfite has a wide variety of applications in various industries:
- To remove excess chlorine in drinking water and neutralize cyanides;
- To eliminate oxygen in the water and feed water boilers;
- In the food industry as a preservative and preventer of food spoilage;
- In the plating industry for wastewater treatment containing chromium ions;
- In the leather industry to lime removal the skin;
- Papermaking (for bleaching wood paste);
- This combination is very suitable for use in photo printing darkrooms in photography due to its acidic and preservative properties;
- In the cosmetics industry as a preservative;
- As a reducing agent for purification and separation of aldehydes and ketones in the chemical industry;
- As a source of SO2 production in gold cyanidation processes.
Application of Sodium Metabisulfite in Water Treatment:
Sodium metabisulfite acts as an antibacterial agent in water treatment. This material is used to clean the mass of water pipes in the desalination plant. This substance reduces excess chlorine in the purification process and is a factor for reducing oxygen soluble in water, used for special purposes.
The use of sodium metabisulphite in water treatment can reduce the amount of excess chlorine in the water. It can also absorb O3 and reduce its amount in water. Chlorine and ozone are two oxidizing substances that destroy water if they reach the reverse osmosis process during water treatment.
Sodium Metabisulfite As a Preservative in the Food Industry:
Sodium Metabisulfite is mainly used as a preservative to prevent the growth of bacteria in food and increase shelf life, prevent browning, and loss of freshness in fruits, vegetables, and other foods.
Foods that contain the most sulfite compounds include sauces, processed products such as fresh sausages and burgers, some seafood such as oysters, and soy-containing compounds.
Exposure to this compound can irritate the skin, eyes, and respiratory tract. This substance may cause allergies if inhaled.
Inhalation of SMBS dust can aggravate asthma or other lung diseases and may cause headaches, difficulty breathing, or irregular heartbeat. Swallowing this substance may also irritate the gastrointestinal tract, nausea, vomiting, and diarrhea.
Contact with skin may cause minor irritation, itching, redness, and swelling. Contact of this chemical with the eyes causes redness, tears, and irritation of the eyes.
Packing and Storage:
Keep the container tightly closed in a dry and well-ventilated place.