The sodium bisulfite is an inorganic solid formed by a sodium ion Na+ and a bisulfite ion HSO3-. Its chemical formula is NaHSO3. It is a white crystalline solid and due to its antioxidant properties it is widely used as a food preservative (for example in some jams).
The NaHSO3 It is a reducing chemical compound, which is the opposite of oxidant, and for this reason it acts as an antioxidant in many of its applications, such as in edible products, as it prevents their deterioration.
However, this use has been questioned as cases of asthma have been reported in people after they have eaten foods that contain sodium bisulfite. It is even said to destroy vitamin B1 in these.
International health organizations have restricted its use to micro-amounts in food.
However, sodium bisulfite has many other uses, such as in obtaining iodine, as an anti-infective, to whiten tissues, for the digestion of wood during the preparation of paper pulp, as a disinfectant for beer and wine barrels , etc.
Article index
Sodium bisulfite is made up of a sodium cation Na+ and a bisulfite anion HSO3-.
In aqueous solutions bisulfite forms 4 species. In dilute solution there is a balance between the structures shown below:
When the concentration increases, two bisulfite molecules interact with each other, forming the pyrosulfite ion StwoOR5two-:
-Sodium bisulfite
-Sodium hydrogen sulphite
-Sodium hydrosulfite.
Solid white crystalline.
104.06 g / mol
It decomposes.
1.48 g / cm3 at 20 ºC.
Soluble in water: 29 g / 100 g of water.
Its solutions are acidic, with a pH between 2.5 and 5.5.
In aqueous solution sodium bisulfite NaHSO3 separates into its ions: the sodium cation Na+ and the bisulfite anion HSO3-.
If sodium bisulfite is exposed to air it loses some SOtwo and slowly oxidizes to Na sulfatetwoSW4.
If heated to decomposition, it emits fumes of sulfur oxides and sodium monoxide..
It is a reducing agent, which is the opposite of oxidant. And for this reason it can behave as an antioxidant.
It has a slight smell of sulfur. It is not flammable.
NaHSO sodium bisulfite3 It is a strong irritant to skin and tissues. Dust irritates the eyes, nose and throat. Ingestion irritates the stomach. Large doses can cause violent colic, diarrhea, depression, and death..
It is not combustible but if heated it produces irritating and toxic gases.
It is prepared by saturating a sodium carbonate solution NatwoCO3 with sulfur dioxide SOtwo and crystallizes in solution.
The NaHSO3 It is used in the digestion of wood, so that it can later become paper. It also serves as a pulp bleach.
It is also used to remove chlorine when paper pulp has been bleached with it..
Sodium bisulfite, due to its reducing property, acts as an antioxidant.
It is used as a preservative in a large number of foods and beverages, including wine and beer, to prevent spoilage and improve flavor.
It is used to whiten foods, such as certain edible starches.
It reduces or prevents food spoilage, allows conditioning of the dough used in baked goods and serves to soften the corn kernels during wet milling, among other uses.
In addition to controlling the fermentation of wine and beer, it acts as an antiseptic in its preparation as it serves as a sterilant and fungicide in barrels and vats..
In dried fruits it is found in concentrations above 100 ppm (ppm means “parts per million”), in many other foods it is found in concentrations between 10 and 100 ppm, such as frozen and dried potatoes, pickles, sauces and jams.
There has been some concern about both the immediate and long-term toxic effects of sodium bisulfite in food. There are divergent opinions.
There are reports of adverse reactions in patients with asthma, which is a respiratory disease, after ingestion of food with NaHSO3. Other sources indicate that the bisulfite ion can destroy vitamin B1 or thiamine.
However, certain researchers in 1985 found that sodium bisulfite serves to protect against radiation and chemical agents, and inhibits or prevents the transformation of cells towards cancer. Low doses are the best.
This protective effect has been explained based on its reducing or antioxidant properties and that in this way it could attack free radicals.
On the other hand, the World Health Organization, or WHO (for its acronym in English World Health Organization), recommends as an acceptable level of daily intake about 0.7 mg / Kg of the person's weight.
That means it is recommended not to exceed that amount..
The United States Food and Drug Administration, or USFDA. US Food and Drug Administration), classified sodium bisulfite as "generally recognized as safe".
NaHSO used at low concentrations3 serves as a plant growth regulator, to enhance photosynthesis and promote crop yield.
It has been tested for this purpose in various types of plants, such as strawberry and tea plants..
It is the active ingredient in many pesticides and biocides.
In aquatic environments it can also accelerate the transformation of certain herbicides to less toxic products by removing chlorine..
The NaHSO3 is the reducing compound used to liberate iodine from sodium iodate NaIO3. This is one of the ways to obtain iodine from sources such as nitro from Chile or some saline waters.
After crystallizing the sodium nitrate from the crude Chile nitrate solution, a NaIO solution remains3 which is treated with sodium bisulfite NaHSO3, generating free iodine.
2 NaIO3 + 5 NaHSO3 → 3 NaHSO4 + NatwoSW4 + Itwo
The NaHSO3 It has been tested to modify soy proteins and improve their adhesion properties with wood in order to glue pieces of wood together to prepare for example chipboards, cardboard or papier-mâché, plywood, etc. All for furniture or boards, among various applications.
This is done to replace traditional formaldehyde-based adhesives because both in their manufacturing process and during their use they tend to release formaldehyde into the atmosphere, which is a toxic compound..
Sodium bisulfite improves the solids content of the soy protein adhesive, and reduces its viscosity, improving its fluidity, so it better penetrates the pores of the wood, increasing its cohesion with it and between the pieces..
The NaHSO Modified Soy Protein Adhesive3 has good water resistance and excellent storage stability due to the antioxidant action of sodium bisulfite.
This confirms that NaHSO modified soy protein adhesives3 are comparable to formaldehyde-based adhesives and can be used in the furniture and wood industry, being less polluting.
It has multiple uses, generally based on its reducing properties (which is the opposite of oxidant). Here are some applications.
-In photography.
-In leather tanning, to remove hair from hides.
-Therapeutic uses: anti-infective. It is used as an antioxidant in some eye drops.
-In the extraction of natural gas by hydraulic fracturing.
-In the coloring of fibers it is used for the preparation of hot or cold bathtubs, to solubilize certain dyes or colorants.
-As a reducer in laundry or bleaching, to whiten wool, silk and vegetable fibers.
-In chemistry labs to remove permanganate stains from skin and clothing. In biochemistry laboratories as a preservative for liquids or solutions that can deteriorate over time. As a chemical reagent.
-For the coagulation of rubber latex.
-In the cosmetic industry as an antioxidant.
-Disinfectant and bleach.
-In the treatment of wastewater to eliminate the chlorine used in the final stage of disinfection and to discharge the already treated water to the environment.
Yet No Comments