Sodium Thiosulfate

Dechlorination Products - Sodium Thiosulfate

**Product Description**
Product	Assay. WT. %	Specific Gravity 25ºC	pH 5% solution
30% solution	30.0	1.28	8.0
Anhydrous	97.0	1.70	8.0
Pentahydrate	99.2	1.70	8.0

**Chemistry of Dechlorination**
Chemical	Reaction	Theoretical Use Ratio
Sodium Thiosulfate (pH 11)	Na₂S₂O₃ + 4CI₂ + 5H₂O (to) 2NaHS0₄ + 8HCI	0.556
Sodium Thiosulfate (pH 6.5)	Na₂S₂O₃ + CI₂ + H₂O (to) Na₂S0₄ + S + 2HCI	2.225
Sodium Bisulfite	Na₂HSO₃+ CI₂ + H₂O (to) NaHS0₄ + 2 + 2HCI	1.455
Sodium Sulfite	Na₂SO₃+ CI₂ + H₂O (to) Na₂S0₄ + 2 +2HCI	1.775
Sulfur Dioxide	SO₃+ CI₂ + 2H₂O (to) H₂S0₄ + 2HCI	0.903
Hydrogen Peroxide	H₂O₂+ CI₂ (to) 2HCI + 0₂ (g)	0.488

Freeze Point Information

Solutions of all the dechlorination agents will freeze in cold temperatures. However, this problem can be minimized with careful planning. Options include:

Housing the chemical in an existing storage facility
Storing the chemical in tanks designed for cold weather
Burial of tanks and lines underground

Choice of Dechlorination Agent

Although all the products listed are effective dechlorination agents, the correct choice depends upon the specific use location and the type of effluent being treated. JCI can advise you on the best dechlorination agent for your situation. We have in-depth experience in a broad range of end-use applications. We supply products and technical expertise to the chloralkali, pulp and paper, textile and municipal wastewater industries. The table below lists the advantages and disadvantages of the various dechlorination agents:

Chemical	Advantages	Disadvantages
Sodium Thiosulfate	Significant use history Non-toxic, non-corrosive, easy to use Low initial capital costs Easy to inject	Solutions subject to freezing in cold weather
Sodium Bisulfite	Significant use history Easy to inject Low use ratio	Sodium bisulfite is corrosive Solutions subject to freezing in cold weather
Sodium Sulfite	Significant use history Non-toxic, non-corrosive, easy to use	High use ratio Solutions subject to freezing in cold weather
Sulfur Dioxide	Significant use history Inexpensive for large installations Injection equipment similar to that for chlorine gas can be used	Corrosive and hazardous to use Initial capital costs are high May increase hazard liability insurance Requires special storage and handling equipment Expensive for small installations
Hydrogen Peroxide	Easy to inject	Does not remove chloramines at a useful rate Highly unstable and subject to deterioration

For Chemical Emergency Spill, Leak, Fire, Exposure or Accident,
Call CHEMTREC, Day/Night at 800.424.9300.

Always read and follow the product label and Material Safety Date Sheet (MSDS) that are shipped with each order.

The information presented herein is based on data considered to be accurate and that reflects the requirements of the OSHA Hazard Communication Standards in effect as of the date of preparation of this Product Specification Sheet. However, no warranty or representation, express or implied, is made as to the accuracy or completeness of the foregoing data and safety information. In addition, no responsibility can be assumed by vendor for any damage or injury resulting from abnormal use, from any failure to adhere to recommended practices or from any hazards inherent in the nature of the product.