Sodium Dichloroisocyanurate

Sodium dichloroisocyanurate, also known as, sodium troclosene, SDIC and NaDCC, is a commonly used disinfectant and water purifying agent. As the sodium salt of chlorinated hydroxytriazine, SDIC chemical is the form of hypochlorous acid as a source of free available chlorine. It has strong oxidizing properties and strong killing effect on various pathogenic microorganisms such as viruses, bacterial spores and fungi. Sodium dichloroisocyanurate disinfectant is a kind of bactericide with wide application range and high efficiency.

SDIC.2H2O usually refers to sodium dichloroisocyanurate dihydrate, which is a hydrated crystalline form of dichloroisocyanuric acid disinfectant (chemical formula contains 2 molecules of water of crystallization). Its core active ingredient remains dichloroisocyanuric acid, which typically appears as a white crystalline powder or granules. It also possesses highly effective and broad-spectrum bactericidal properties and is readily soluble in water, releasing hypochlorous acid.

The common forms of sodium dichloroisocyanurate are white crystalline powder or granules. Some products are also made into SDIC tablets (such as swimming pool disinfection tablets and drinking water disinfection tablets) according to application requirements. The core components are the same in different forms, designed only to adapt to the dosage control and ease of operation in different usage scenarios. Among them, SDIC powder and SDIC granule dissolve faster, while the SDIC tablet is more convenient for precise dosing and storage.

Chemical form: SDIC is anhydrous, while SDIC.2H2O is a hydrated crystalline form (containing two molecules of water of crystallization).

Available chlorine content: SDIC has a higher available chlorine content, typically 50%-60%.  SDIC.2H2O, due to the presence of water of crystallization, has a slightly lower available chlorine content, generally around 40%-50%.

Physical properties: SDIC.2H2O has relatively weak hygroscopicity and better stability during storage (less prone to clumping). SDIC is more hygroscopic and requires more stringent sealing for storage.

Application scenarios: While both have the same core bactericidal purpose, SDIC.2H2O is more suitable for scenarios with less stringent storage requirements, while SDIC is more suitable for scenarios requiring high available chlorine concentrations and rapid bactericidal action.

Dichloroisocyanuric acid has stronger chemical stability, making it safer to store and transport. Its effective chlorine content is typically between 50% and 60%, resulting in higher and longer-lasting sterilization efficiency.

Sodium hypochlorite has a lower effective chlorine content (generally 5%-10%), is less stable, and is easily decomposed by light and temperature. It also has a more pronounced pungent odor and must be prepared and used immediately.

Furthermore, dichloroisocyanuric acid has a wider range of applications, suitable for disinfection of solids, liquids, and in various environmental scenarios.

The effective chlorine content and water content are different. SDIC.2H2O is a mixture of SDIC and soda ash, with low solubility and low cost. Sodium dichloroisocyanurate is purified and has good solubility and high cost.

Adding an appropriate amount of NaDCC disinfectant to drinking water can quickly kill microorganisms, including various germs and viruses. But you need to pay attention to the following aspects when using:

Know about the properties of disinfectants, and be familiar with how to use them and how much to use.

Properly formulated. On the basis of knowing the chlorine content of NaDCC disinfectant, calculate accurately to ensure sufficient disinfectant concentration.

Dichloroisocyanuric acid can be used as a bleaching agent in the textile industry. Compared with other bleaching agents, SDIC chemical has great advantages. Bleach in the traditional sense can only be used at lower temperatures, while SDIC can still achieve good bleaching effect even at higher temperature. In addition, it only destroys the molecular structure of natural fibers and synthetic fibers to a lesser extent, so as to reduce the impact on fiber strength.

As an efficient disinfectant, the sterilization ability of NaDCC disinfectant is strong and durable. Soaking the tableware in water with an appropriate amount of dichloroisocyanuric acid for 2 minutes can kill 100% of Escherichia coli. After soaking and disinfecting for 8 minutes, the survival rate of Bacillus is reduced to only 2%. After 15 minutes, the hepatitis B virus will be completely killed.

Its core bactericidal effect lies in its decomposition in water to produce hypochlorous acid (HClO). Hypochlorous acid has strong oxidizing properties, capable of destroying the cell membrane structure of microorganisms such as bacteria, viruses, and fungi, interfering with their nucleic acid and protein synthesis, thereby thoroughly killing microorganisms. It has a good killing effect on bacterial vegetative cells, spores, viruses, and fungal spores.

When used for drinking water disinfection, relevant standards must be strictly followed: Generally, the dosage is 0.5-2.0 mg/L (based on effective chlorine). The specific dosage needs to be adjusted according to the raw water quality (turbidity, microbial content). After disinfection, the residual chlorine content in drinking water should be maintained at 0.3-0.5 mg/L. This ensures sterilization effectiveness while avoiding excessive residual chlorine that may produce odors or harmful byproducts. It is recommended to conduct a small-scale test before large-scale application to confirm the absence of abnormalities.  

Yes, but the scope and dosage must be strictly limited.

According to food hygiene standards, SDIC can be used for disinfection of floors, walls, and equipment surfaces (such as workbenches and conveyor belts) in food processing workshops, as well as for disinfection of water used in food processing.

When used for equipment surface disinfection, it should be prepared into a solution with an effective chlorine concentration of 200-500 mg/L. After wiping or soaking, it must be rinsed thoroughly with clean water to avoid residue.

When used for food processing water, the dosage should be controlled at 0.2-0.5 mg/L (based on effective chlorine) to ensure that the water quality after disinfection meets the standards for water used in food processing.

The core principle of preparation is “add water first, then add the agent” to avoid dangerous local concentrations:

① Determine the required solution concentration and volume, and calculate the amount of dichloroisocyanuric acid needed.

② Prepare a clean container and add an appropriate amount of water.

③ Slowly add the weighed SDIC powder or granules to the water while stirring constantly until completely dissolved.

④ After dissolution, use immediately or seal and store temporarily, depending on your needs.

The contact time needs to be adjusted according to the disinfection scenario and the target microorganisms. Generally, the following is recommended:

① To kill common vegetative bacteria: 10-30 minutes.

② To kill bacterial spores and viruses: 30-60 minutes.

③ Environmental disinfection: Keep the environment moist for at least 30 minutes after spraying.

④ Medical device disinfection: Immersion disinfection requires at least 30 minutes, rinse thoroughly with sterile water after disinfection.

Long-term storage is not recommended.   

NaDCC solution has poor stability and is easily affected by factors such as light, temperature, and pH, leading to a decrease in effective chlorine content, weakened bactericidal effect, and potential generation of harmful substances.    

It is recommended to prepare and use immediately. If short-term storage is necessary, it must be sealed and stored in a cool, dark, and dry environment for no more than 24 hours. Proper labeling is essential to prevent accidental ingestion or misuse.

It is not recommended to mix them indiscriminately.

In particular, it should not be mixed with acidic substances (such as hydrochloric acid and acetic acid) or ammonia-based substances, as this will produce toxic chlorine gas, which is harmful to human health.    

It should also not be mixed with other chlorine-containing disinfectants, as this may result in excessively high effective chlorine content, increasing irritation and corrosiveness. If changing disinfectants, the old disinfectant residue must be thoroughly cleaned before using the new disinfectant.

Under correct storage conditions, the shelf life of sodium dichloroisocynaurate is generally 2-3 years. Improper storage (such as moisture absorption, heat exposure, or inadequate sealing) will shorten the shelf life. Before use, check the product’s production date and expiration date. If the expiration date has passed, or if the product shows signs of deterioration such as clumping, discoloration, or unusual odor, it must not be used.

① Sealed storage: Place SDIC chemical in a well-sealed container to prevent moisture absorption, clumping, and loss of active ingredients.

② Storage environment: Store in a cool, dry, and well-ventilated warehouse, away from fire and heat sources (temperature not exceeding 30℃), and avoid direct sunlight.

③ Separate storage: Store separately from acidic substances, ammonia, food, medicine, and feed. Mixing is strictly prohibited. Clear warning signs must be posted in the warehouse.

① Packaging requirements: Use packaging containers that meet national standards. The packaging must be sturdy and sealed to prevent leakage and damage during transportation.

② Transportation method: Choose appropriate transportation vehicles. Avoid transporting dichloroisocyanuric acid in the same vehicle as acidic substances or ammonia. The transport vehicle must be equipped with appropriate fire-fighting equipment and emergency response equipment.

③ Environmental Requirements: During transportation, exposure to direct sunlight, rain, and high temperatures must be avoided. Cooling measures are necessary during summer transportation.

④ Safety Labeling: Transport vehicles must display warning labels such as “Corrosive Substances” and “Toxic Substances.” Drivers must be familiar with emergency response procedures and regularly check the packaging condition en route.