ANHYDROUS SODIUM SULFITE FOR WATER TREATMENT
|Sodium sulfite(Na2SO3) %≥||97|
|Water insoluble material %≤||0.02|
|Free alkali(Na2SO3) %≤||0.1|
Sodium sulfite (sodium sulphite) is a soluble sodium salt
of sulfurous acid (sulfite) with the chemical formula
Na2SO3. It is a product of sulfur dioxide scrubbing, a part of the
flue-gas desulfurization process. It is also used as a preservative
to prevent dried fruit from discoloring, and for preserving meats,
and is used in the same way as sodium thiosulfate to convert
elemental halogens to their respective hydrohalic acids, in
photographyand for reducing chlorine levels in pools.
Sodium Sulfite is a white crystal or powder with reducing property.
Sodium sulfite exhibits bleaching, de-sulfurizing, and
dechlorinating activities. This agent was used by food industry to
help maintain the fresh appearance of food products. It is also a
component in many drugs, which helps maintain their potency and
stability. FDA has ruled sodium sulfite a new animal drug of low
SODIUM SULFITE is a white odorless powder. Density 2.633 g / cm3.
Moderately toxic. Sinks in water and dissolves slowly. Also
transported as a heptahydrate Na2SO3.7H2O.
Sodium sulfite is primarily used in the pulp and paper industry. It
is used in water treatment as an oxygen scavenger agent, to treat
water being fed to steam boilers to avoid corrosion problems, in
the photographic industry to protect developer solutions from
oxidation and (as hypo clear solution) to wash fixer (sodium
thiosulfate) from film and photo-paper emulsions, in the textile
industry as a bleaching, desulfurizing and dechlorinating agent and
in the leather trade for the sulfitization of tanning extracts. It
is used in the purification of TNT for military use. It is used in
chemical manufacturing as a sulfonation and sulfomethylation agent.
It is used in the production of sodium thiosulfate. It is used in
other applications, including froth flotation of ores, oil
recovery, food preservatives, and making dyes.
Sodium sulfite forms a bisulfite adduct with aldehydes, and with
ketones forms a sulfonic acid. It is used to purify or isolate
aldehydes and ketones.
Sodium sulfite is decomposed by even weak acids, giving up sulfur
Na2SO3 + 2 H+ → 2 Na+ + H2O + SO2
A saturated aqueous solution has pH of ~9. Solutions exposed to air
are eventually oxidized to sodium sulfate. If sodium sulfite is
allowed to crystallize from aqueous solution at room temperature or
below, it does so as a heptahydrate. The heptahydrate crystals
effloresce in warm dry air. Heptahydrate crystals also oxidize in
air to form the sulfate. The anhydrous form is much more stable
against oxidation by air.
|Sodium sulfite|| |
|Other names|| |
|Hypo clear(photography)|| |
|CAS Number||· 7757-83-7|
|3D model (JSmol)||· Interactive image|
|E number||E221 (preservatives)|
|PubChem CID||· 24437|
|Molar mass||126.043 g/mol|
|Density||2.633 g/cm3 (anhydrous)|
|1.561 g/cm3 (heptahydrate)|| |
|Melting point||33.4 °C (92.1 °F; 306.5 K) (dehydration of heptahydrate)|
|500 °C (anhydrous)|| |
|Boiling point||Decomposes(separate (substances) into constituent elements)|
|Solubility in water||27.0 g/100 mL water (20 °C)|
|Solubility||soluble in glycerol insoluble in ammonia,chlorine|
|Acidity (pKa)||~9 (heptahydrate)|
|Crystal structure||hexagonal (anhydrous)|
|monoclinic (heptahydrate)|| |
|Safety data sheet||ICSC 1200|