Sodium metabisulfite (Na2S2O5), also known as disodium metabisulfite, is a chemical compound with a broad range of uses across various industries. Its versatility as a reducing agent, preservative, and bleaching agent has made it a valuable component in sectors ranging from food preservation to pharmaceuticals and environmental management. This article provides a comprehensive overview of sodium metabisulfite, including its chemical properties, industrial production processes, applications, and potential future uses.
1. Chemical Properties of Sodium Metabisulfite
Molecular Structure and Composition
Sodium metabisulfite has the chemical formula Na2S2O5. It is composed of two sodium (Na) atoms, two sulfur (S) atoms, and five oxygen (O) atoms. The compound typically appears as a white, crystalline powder or granules that have a strong sulfurous odor, particularly when exposed to air. The compound’s structure can be represented as:
Na2S2O5
Each molecule of sodium metabisulfite consists of two sulfite (SO32) units bound together by a sodium ion. When dissolved in water or exposed to acidic conditions, sodium metabisulfite releases sulfur dioxide (SO2), a gas that contributes to its reactivity.
Chemical Reactions
Sodium metabisulfite is widely known for its ability to act as a reducing agent. In various reactions, it releases sulfur dioxide, which serves to reduce other substances, making it an essential compound in many chemical processes.
- Hydrolysis Reaction:
When sodium metabisulfite comes into contact with water, it hydrolyzes to form sodium bisulfite (NaHSO3) and sulfur dioxide (SO2):
Na2S2O5+H2O→2NaHSO3
This reaction is particularly important in water treatment processes, where the release of sulfur dioxide neutralizes chlorine and other oxidizing agents.
2. Reaction with Acids:
In the presence of acidic solutions, sodium metabisulfite releases sulfur dioxide, which is utilized in various industrial applications, including bleaching and disinfection:
Na2S2O5+H2SO4→2NaHSO3+SO2
3.Oxidation Reactions:
Sodium metabisulfite can also undergo oxidation, particularly in the presence of oxygen or other oxidizing agents:
Na2S2O5+O2→Na2S2O6
This reaction is relevant in industries that require stronger oxidizing agents, such as in certain bleaching processes.
2. Industrial Production of Sodium Metabisulfite
Sodium metabisulfite is typically produced through two main methods: the sulfite process and the sodium bisulfite process. These methods involve reacting sodium bisulfite with sulfur dioxide (SO2), typically in an aqueous medium, to form sodium metabisulfite.
Sulfite Process
In the sulfite process, sodium carbonate (Na2CO3) or sodium hydroxide (NaOH) reacts with sulfur dioxide (SO2) in water to form sodium bisulfite. The sodium bisulfite is then dehydrated to form sodium metabisulfite. The reaction proceeds as follows:
Na2CO3+SO2+H2O→Na2S2O5+CO2
This process is employed in large-scale industrial production, particularly when cost-effectiveness and simplicity are the primary goals.
Sodium Bisulfite Process
The sodium bisulfite process involves dissolving sodium hydroxide in water and then bubbling sulfur dioxide through the solution. Sodium bisulfite is formed in the reaction and is further treated and dehydrated to produce sodium metabisulfite:
NaHSO3→Na2S2O5+H2O
This process yields sodium metabisulfite in a purer form, suitable for sensitive applications, such as pharmaceuticals and food preservation.
3. Applications of Sodium Metabisulfite
Sodium metabisulfite has a broad array of applications, including food preservation, water treatment, pharmaceuticals, textiles, and cosmetics. The compound’s effectiveness as a reducing agent, preservative, and antioxidant makes it a key ingredient in these industries.
3.1. Food and Beverage Industry
Sodium metabisulfite is widely used in the food industry as a preservative, antioxidant, and bleaching agent. Its primary role is to prevent the oxidation of food products, maintain their appearance, and extend shelf life.
Dried Fruit Preservation
Sodium metabisulfite is commonly used in the preservation of dried fruits. It helps prevent browning and preserves the natural color of fruits like apricots, raisins, and peaches. Without sodium metabisulfite, these fruits would experience enzymatic browning, which can lead to loss of appeal and nutritional value.
- Dried fruit. In dried fruit such as apricots, sodium metabisulfite helps retain colour and flavour during storage – which matters for products that are held and shipped long distances.
Wine Production
Sodium metabisulfite is used in winemaking to prevent oxidation and spoilage by inhibiting the growth of undesirable bacteria and yeasts. The compound also helps maintain the clarity and color of wine by acting as an antioxidant.
- Wine. In winemaking, small sulfite additions at different stages protect white wine in particular against oxidation, helping to preserve flavour and aroma and to extend shelf life.
3.2. Water Treatment
Sodium metabisulfite plays a crucial role in water treatment, specifically in dechlorination. Chlorine, commonly used in municipal water treatment, can leave residual tastes and odors in drinking water. Sodium metabisulfite is added to neutralize chlorine and make the water more palatable.
- Municipal drinking water. In municipal treatment, sodium metabisulfite is used to remove the excess chlorine left after disinfection, so the water reaches customers without a chlorinous taste or odour.
3.3. Textile Industry
Sodium metabisulfite is employed in the textile industry as a bleaching agent and reducing agent. It is used to remove excess dye from fabrics and ensure a uniform and high-quality finish.
- Textiles. In textile processing, sodium metabisulfite is used as an antichlor after bleaching and in dyeing to strip residual oxidising agents, giving more consistent whiteness and colour.
3.4. Pharmaceutical Industry
Sodium metabisulfite is used as an antioxidant and preservative in pharmaceuticals, particularly in injectable medications. It helps stabilize active ingredients, preventing degradation due to oxidation, which is especially important for biologics and sensitive drugs.
- Pharmaceuticals. As an antioxidant excipient, sodium metabisulfite is used in some formulations to protect oxidation-sensitive actives and help maintain potency through shelf life.
3.5. Cosmetics and Personal Care Products
Sodium metabisulfite’s antioxidant properties make it valuable in cosmetic and personal care formulations, such as shampoos, conditioners, and skin care products. It helps maintain the stability of active ingredients by preventing oxidative degradation.
- Cosmetics. In cosmetic formulations, small amounts of metabisulfite can act as an antioxidant to protect oxidation-sensitive ingredients such as vitamin C.
3.6. Chemical Manufacturing
In chemical manufacturing, sodium metabisulfite is used as a reducing agent in several reactions. It is essential in the production of sodium hydrosulfite, which is used as a bleaching agent in paper and textile industries.
Sodium Hydrosulfite Production
A paper mill in Germany used sodium metabisulfite to produce sodium hydrosulfite, a powerful reducing agent commonly used for bleaching wood pulp. By improving the bleaching process, the mill significantly reduced the amount of chlorine-based chemicals used, which lowered the environmental impact of their operations. The company reported not only a 10% reduction in chemical costs but also a reduction in the volume of chlorine-based waste generated. This change helped the mill comply with stringent environmental regulations while achieving a higher-quality product at a lower cost.
Sodium metabisulfite is also employed in a variety of other chemical synthesis applications, such as in the production of formaldehyde, where it acts as a reducing agent to stabilize certain compounds. The compound is valuable in industries that require the reduction of chemical species in a controlled manner, ensuring the desired properties of the final products.
4. Emerging Applications of Sodium Metabisulfite
While sodium metabisulfite has long been used in established industries, recent developments and research suggest that it has a growing range of potential applications, particularly in more niche and emerging industries.
4.1. Applications in the Electronics Industry
The electronics industry, especially semiconductor manufacturing, requires high-purity materials and precise chemical treatments. Sodium metabisulfite’s ability to reduce metal oxides and other contaminants makes it a candidate for cleaning semiconductor wafers. During the production of electronic components such as integrated circuits, chips, and photovoltaic cells, sodium metabisulfite could play a critical role in maintaining the purity of the materials by removing metal oxide layers and other impurities.
- Electronics. In electronics, sulfite-based solutions are used in some wafer-cleaning and surface-treatment steps where thin oxide films must be removed; the work is process-specific and is validated per line.
4.2. Biofuels and Renewable Energy Production
As the world shifts toward renewable energy, sodium metabisulfite could play an important role in biofuel production. Biofuels, such as bioethanol and biodiesel, require the processing of biomass—such as wood, agricultural waste, or algae—into usable fuels. One of the challenges in biofuel production is the removal of contaminants and the enhancement of fermentation processes. Sodium metabisulfite, due to its reducing properties, could be used in the pretreatment of biomass to break down complex sugars, making them more accessible to fermenting microorganisms.
- Bioethanol and biomass. Sulfite chemistry is used in some biomass pretreatments to help make sugars more accessible to fermentation, improving process efficiency compared with untreated feedstock.
Sodium metabisulfite can also be used to reduce the presence of heavy metals in biofuels, improving their purity and quality. This could lead to the development of more efficient and sustainable biofuel production processes.
4.3. Waste Management and Environmental Remediation
Sodium metabisulfite’s ability to neutralize chlorine and other oxidizing agents makes it a potential tool for managing industrial waste, especially in industries that produce sulfur-containing compounds. It could be employed to neutralize harmful byproducts in the chemical, mining, and oil refining industries. Sodium metabisulfite can help reduce the toxicity of pollutants, making it safer for disposal or further treatment.
In addition, sodium metabisulfite can be used in environmental remediation efforts, such as soil decontamination. When soils are contaminated with heavy metals or other pollutants, sodium metabisulfite can reduce the toxicity of these substances, helping to restore the soil to a usable state. This process could be particularly valuable in mining areas, where heavy metals like mercury and arsenic are common pollutants.
- Mine water and tailings. In mining, sodium metabisulfite reduces oxidising species in process and tailings water – for example to remove residual chlorine and to lower redox potential – and it is the standard reagent for destroying residual cyanide after gold leaching (see below).
4.4. Sodium Metabisulfite in Green Chemistry
As the focus on sustainability and green chemistry continues to grow, sodium metabisulfite’s role in eco-friendly manufacturing processes is becoming more prominent. It offers an environmentally benign alternative to harsher chemicals that are often used for oxidation or disinfection. Sodium metabisulfite’s ability to neutralize chlorine, sulfur compounds, and other pollutants without generating harmful byproducts makes it an attractive solution for industries that are seeking to reduce their environmental footprint.
In the future, sodium metabisulfite could be further optimized for use in sustainable manufacturing processes, particularly in the production of biodegradable plastics, eco-friendly detergents, and other green products. Its potential as a low-impact chemical in environmental remediation and clean industrial processes could position it as a key player in the green chemistry movement.
5. Safety and Environmental Considerations
Sodium metabisulfite is generally considered safe when handled properly, but like any chemical compound, it requires careful management. The most significant safety concern with sodium metabisulfite is the release of sulfur dioxide (SO2), a gas that can be harmful if inhaled in large amounts. Sulfur dioxide can irritate the respiratory system, eyes, and skin, and exposure to high concentrations can cause serious health issues, particularly in individuals with respiratory conditions such as asthma.
To mitigate these risks, it is important to store sodium metabisulfite in a well-ventilated area and use appropriate personal protective equipment (PPE), such as gloves, goggles, and respirators when handling the compound. Additionally, sodium metabisulfite should be stored away from acids and oxidizing agents to prevent unwanted reactions.
In industrial settings, proper ventilation and safety protocols should be in place to ensure that sulfur dioxide is not released into the air in harmful quantities. In the case of spills, sodium metabisulfite should be cleaned up promptly, and any contaminated areas should be ventilated to remove the gas from the environment.
Environmental Impact
From an environmental standpoint, sodium metabisulfite has relatively low toxicity and is considered biodegradable. When used in water treatment, for example, the byproducts are generally harmless, as sulfur dioxide (SO2) and sodium chloride (NaCl) are both naturally occurring substances. However, like any chemical, sodium metabisulfite should be used in accordance with local regulations to minimize its environmental impact.
In industries where sodium metabisulfite is used in large quantities, such as in food preservation or textile processing, it is essential to control its release into the environment to prevent contamination of air and water systems. Regulatory bodies such as the Environmental Protection Agency (EPA) and local environmental agencies often monitor the use of such chemicals to ensure that industrial practices are sustainable and non-harmful.
6. Conclusion: The Future of Sodium Metabisulfite
Sodium metabisulfite is an incredibly versatile chemical that plays a vital role in numerous industries. Its uses as a preservative, bleaching agent, reducing agent, and antioxidant have made it a key component in food processing, water treatment, pharmaceuticals, textiles, and cosmetics. As industries continue to focus on sustainability and greener manufacturing practices, the role of sodium metabisulfite is expected to grow, particularly in environmentally-conscious applications such as biofuels, waste management, and green chemistry.
In addition, emerging applications in fields like semiconductor manufacturing and environmental remediation highlight the potential of sodium metabisulfite to expand its influence across new and exciting sectors. Its ability to neutralize harmful substances and reduce environmental pollution makes it an essential chemical for industries seeking to minimize their environmental footprint.
However, as with any chemical, careful handling, storage, and usage are critical to ensuring safety and minimizing environmental impact. With continued research and development, sodium metabisulfite has the potential to remain a key player in industrial applications, supporting the growth of sustainable and environmentally friendly manufacturing practices.
Ultimately, the versatility, low toxicity, and wide range of applications of sodium metabisulfite position it as an indispensable compound in modern industry. From food preservation to cutting-edge chemical manufacturing, sodium metabisulfite’s importance will only continue to rise in the coming years, contributing to safer, more efficient, and more sustainable processes across a variety of sectors.
Further technical detail on metabisulfite
The following sections expand on the technical and practical aspects covered above.
Specifications
| Parameter | Typical value | Significance |
|---|---|---|
| Assay (as Na2S2O5) | 96-98% min (grade-dependent) | Active content |
| SO2 content | ~65-67% (equivalent) | Directly correlates with preservative/reducing power |
| Iron | Low (e.g. <0.005%) | Color and purity for food/photo uses |
| Water-insolubles | Low | Purity |
| Heavy metals | Low (food grade must meet limits) | Food safety |
| Appearance | White to slightly yellow crystalline powder | Visual QC |
FAQ
Is sodium metabisulfite the same as sodium sulfite?
No. Sodium metabisulfite (Na2S2O5) is the bisulfite form; sodium sulfite (Na2SO3) is the normal sulfite. Metabisulfite releases more SO2 per unit and is the common commercial form for preservation and dechlorination.
Is sodium metabisulfite safe in food?
It is an approved food additive (E223) in many regions with usage limits; sulfite-sensitive individuals must be warned via labeling.
How does it remove chlorine from water?
It reduces free chlorine (and chloramine) to chloride, typically at a dose of about 1.5-3 mg/L of metabisulfite per mg/L of chlorine, depending on the form.
What grade should I buy?
Food grade for food applications; technical grade for water treatment, textiles and industrial use; photo grade for photographic applications. Confirm the COA limits.
References and Further Reading
- Peer-reviewed literature on sulfite chemistry and food preservation
- Industry literature on water dechlorination and bleaching
- Food additive regulations (E223, sulfite labeling)
This article is published for industrial and technical reference by PolyblueChem. Specifications are typical industry values; always verify against the supplier’s COA.
PolyblueChem supplies sodium metabisulfite (CAS 7681-57-4) in food and technical grades with COA and MSDS. Contact us for specifications and quotations.
Manufacturing Sodium Metabisulfite
Sodium metabisulfite (Na2S2O5, CAS 7681-57-4) is made by reacting sulfur dioxide with a sodium source and crystallising the product. Two routes dominate.
- From soda ash or caustic soda and sulfur dioxide. Sulfur dioxide is passed into a sodium carbonate or sodium hydroxide solution to form sodium bisulfite, which on further reaction and crystallisation yields sodium metabisulfite. This is the classic industrial route.
- From sodium sulfite and sulfur dioxide. Sulfur dioxide is absorbed into a sodium sulfite solution, and the metabisulfite is crystallised out.
The crystallised product is dried and screened to the required particle size. Because sodium metabisulfite releases sulfur dioxide on contact with moisture and acid, the drying and packaging steps are carried out to keep the product dry and stable.
Dechlorination: Dosage and Practice
One of the most important industrial uses of sodium metabisulfite is removing free chlorine (dechlorination) – for example after disinfection, before discharge, or to protect reverse-osmosis membranes from oxidative damage.
The reaction is a simple redox process: metabisulfite reduces free chlorine to chloride. In practice the stoichiometric requirement is roughly 1.3 to 1.5 mg of sodium metabisulfite per mg of free chlorine, but operators normally dose a modest excess (commonly about 1.5 to 2 mg per mg chlorine) to ensure complete removal, because chlorine demand varies with the water.
| Parameter | Typical guidance |
|---|---|
| Theoretical dose | About 1.3 to 1.5 mg metabisulfite per mg free chlorine |
| Practical dose | Commonly about 1.5 to 2 mg per mg chlorine (a small excess is normal) |
| Control parameter | Residual chlorine (or ORP) measured downstream of dosing |
| Typical applications | Effluent dechlorination, RO membrane protection, process-water treatment |
Because the optimum depends on the actual chlorine residual, most plants control dosing on a measured residual (or on ORP) rather than on a fixed feed rate.
Food Preservation: Sulfite Limits
Sodium metabisulfite is widely used as an antioxidant and preservative in food and beverage processing, where it inhibits browning and microbial growth. In these uses its effect comes from sulfur dioxide (SO2), and regulations set maximum residue limits for SO2 that vary by product and by jurisdiction.
| Use | Role | Regulatory note |
|---|---|---|
| Dried fruit and vegetables | Anti-browning, preservative | SO2 residue limits apply (product-specific) |
| Wine and beverages | Antioxidant, antimicrobial | SO2 limits apply; labelling may be required above a threshold |
| Shrimp and seafood | Prevents blackspot; preservative | SO2 residue limits apply |
| General food processing | Antioxidant, reducing agent | Use and labelling governed by local food law |
Because sulfites can trigger reactions in sensitive individuals, food applications are governed by labelling rules as well as by residue limits. Buyers in food applications should confirm the applicable limits and the required food-grade documentation for their market.
Metabisulfite vs Bisulfite vs Sulfite
These three names appear together often and are frequently confused. The key point is what happens in water.
| Species | Formula | In water |
|---|---|---|
| Sodium metabisulfite | Na2S2O5 | Dissolves to give bisulfite; the solid commercial form of choice |
| Sodium bisulfite | NaHSO3 | The species actually present in solution; usually supplied as the metabisulfite solid or as a solution |
| Sodium sulfite | Na2SO3 | Related reducing agent, used where a sulfite (rather than bisulfite) is wanted |
The practical consequence: when a process calls for “sodium bisulfite solution”, it is very often supplied and dosed as sodium metabisulfite, because the metabisulfite is the stable, easy-to-ship solid that forms bisulfite on dissolution.
Sodium Metabisulfite in Mining
Mining is one of the largest industrial uses of sodium metabisulfite, especially in gold plants and in the flotation circuits of base-metal concentrators.
Gold: cyanide detoxification
After cyanide leaching, the tailings still contain cyanide that has to be destroyed before the water is recycled or discharged. The standard route is the SO2/air process: sulphur dioxide and air oxidise free and weak-acid-dissociable cyanide to cyanate (OCN-). Sodium metabisulfite is a convenient way to generate SO2 in the pulp, usually together with a copper catalyst and lime for pH control.
| Parameter | Typical practice |
|---|---|
| Reagent | Sodium metabisulfite (SO2 source) with air and a copper catalyst |
| SO2 to CN molar ratio | Approx. 4 – 5 to 1 |
| pH | Approx. 8 – 9, controlled with lime |
| Copper catalyst | Approx. 20 – 50 mg/L Cu in the pulp (system-specific) |
| Target | Reduce weak-acid-dissociable cyanide to the level required by the site permit |
Dosing and ratio must be set on site – cyanide concentration, pulp density and the permit limit all vary. Treat these figures as a starting point, not a specification.
Flotation
In flotation, sodium metabisulfite is used as a depressant and pulp-conditioning reagent:
| Function | How it is used |
|---|---|
| Depression of sphalerite (ZnS) | Used in copper-zinc and lead-zinc separation, often with zinc sulphate, to keep zinc out of the copper or lead concentrate |
| Depression of pyrite | Helps suppress iron sulphide in selective circuits |
| Redox / potential control | Acts as a reducing reagent to lower pulp potential where oxidised surfaces reduce selectivity |
Flotation dosage is highly ore-specific and is normally screened in laboratory tests (often in the range of hundreds of grams per tonne of ore) before plant trials.
Because the same reagent serves cyanide destruction, flotation and water treatment, a mining site can often consolidate its metabisulfite demand – one grade, one delivery, one COA stream.
Supplying Sodium Metabisulfite to Africa
Africa combines two of the largest uses of sodium metabisulfite – gold and base-metal mining, and municipal and industrial water treatment – and we supply the region from China with the packaging and paperwork African buyers normally require.
Where it is used in Africa
- Gold plants (for example South Africa, Ghana, Tanzania, Burkina Faso, Mali, Zimbabwe) – cyanide detoxification after leaching.
- Base-metal concentrators (for example Zambia and the DRC for copper, and lead-zinc operations) – flotation depression and conditioning.
- Municipal and industrial water treatment – dechlorination of drinking water and protection of RO membranes.
- Food and beverage processors – sulfite preservation where permitted.
Packaging and delivery
| Form | Typical use |
|---|---|
| 25 kg PP/PE bags | Bagged handling; palletised for container shipment |
| 1000 kg (1 t) jumbo bags | Plant-scale dosing and bulk handling at mine sites |
| Full container loads (20 ft / 40 ft) | Port-to-port supply with palletised or loose jumbo bags |
African discharge ports we quote against include Durban, Mombasa, Dar es Salaam, Tema/Takoradi, Lagos/Apapa, Beira and Walvis Bay. Tell us the port and the quantity and we will quote on an FOB or CIF basis.
Documents and quality
- Certificate of analysis (COA) and safety data sheet (SDS) per batch.
- Food-grade or industrial-grade specification, stated on the quotation.
- Third-party inspection (for example SGS or BV) on request.
- Transport classified as a corrosive solid; the exact UN entry and class are given on the SDS.
For gold and water-treatment buyers who need dependable, repeatable supply, we can quote against an annual or quarterly volume so that grade, packaging and COA come from one source.
Price and Supply
Metabisulfite is a commodity: its price tracks the cost of sulfur, the sodium source (caustic soda or soda ash), energy and freight, so it moves with those markets rather than sitting still. Because we produce and export at scale, we can offer competitive pricing on bulk volumes – the bigger the committed tonnage, the better the terms. For African and other export buyers, buying full container loads in jumbo bags gives the lowest delivered cost per tonne. See what drives the cost of sodium metabisulfite for the levers that matter.
Frequently Asked Questions about Sodium Metabisulfite
What is sodium metabisulfite used for in mining?
Two main uses: destroying residual cyanide in gold tailings by the SO2/air process, and acting as a depressant and pulp-conditioning reagent in flotation (for example to depress sphalerite and pyrite).
How is sodium metabisulfite used to destroy cyanide?
With air and a copper catalyst at pH about 8-9 it oxidises free and weak-acid-dissociable cyanide to cyanate. The SO2 to CN ratio is typically about 4-5 to 1, but the dose must be set on site against the permit limit.
Do you supply sodium metabisulfite to Africa?
Yes. We quote FOB or CIF to African ports including Durban, Mombasa, Dar es Salaam, Tema/Takoradi, Lagos/Apapa, Beira and Walvis Bay, in 25 kg bags or 1000 kg jumbo bags.
What packaging do you offer for mining and water treatment?
25 kg PP/PE bags and 1000 kg jumbo bags, palletised for container shipment or loose in full container loads. Packaging is agreed with the order.
What documents are provided?
Certificate of analysis (COA) and safety data sheet (SDS) per batch, plus third-party inspection on request. Transport is classified as a corrosive solid – the exact UN entry is given on the SDS.
What is sodium metabisulfite used for?
Its main uses are dechlorination in water treatment, protection of RO membranes, food preservation (as a source of SO2), and as a reducing agent in various industrial processes.
How much sodium metabisulfite removes chlorine?
Roughly 1.3 to 1.5 mg per mg of free chlorine theoretically; plants typically dose a modest excess of about 1.5 to 2 mg per mg and control on the measured residual chlorine or ORP.
Is sodium metabisulfite the same as sodium bisulfite?
They are related but distinct. Metabisulfite (Na2S2O5) is the stable solid form; it forms bisulfite when dissolved. In many water-treatment duties the two are used interchangeably on a molar basis, which is why metabisulfite is often supplied for “bisulfite” applications.
What are the food-grade requirements?
Food applications are governed by SO2 residue limits and by labelling rules for sulfites, which vary by product and jurisdiction. A food-grade specification and the relevant documentation should be confirmed for the target market.
How is sodium metabisulfite made?
By reacting sulfur dioxide with a sodium source (such as soda ash or caustic soda), then crystallising and drying the product to the required particle size.
How should sodium metabisulfite be stored?
Dry and sealed, away from moisture, acids and oxidising agents. It releases SO2 on contact with moisture or acid, so packaging integrity and dry storage are essential.
How do I buy sodium metabisulfite?
PolyBlueChem supplies sodium metabisulfite (CAS 7681-57-4) in food and technical grades. Contact our team for specifications, COA and a quotation; see also our sodium metabisulfite buying guide.
Related reading
- Sodium metabisulfite vs bisulfite vs sulfite: choosing a reducing agent
- Sodium metabisulfite for chromium(VI) reduction and metal treatment
- Sodium metabisulfite price and supply: what drives the cost
- Water treatment chemicals overview: coagulants, flocculants, biocides and dechlorination
- Sodium Metabisulfite in Food Preservation
- Sodium metabisulfite in gold mining and flotation
- Sodium metabisulfite for water treatment in Africa
- Sodium metabisulfite export to Africa: grades, packaging, ports and documents
- Sodium Metabisulfite for Dechlorination and RO Protection
- How to Buy Sodium Metabisulfite: Specs and COA