Chlorine dioxide

Chlorine dioxide (ClO2, CAS 10049-04-4) is an inorganic oxidising gas commercially known under trade names including Alcide, EZ Flow, and JUN-CLARE. It carries no assigned E-code and is distinct from chlorine, functioning as a selective oxidant that reacts with electron-rich organic compounds without forming chlorinated by-products.

In water treatment, ClO2 destroys biofilms and inactivates pathogens such as Cryptosporidium by oxidising cell membrane proteins, making it effective at lower concentrations than chlorine. In pulp and paper processing, it selectively bleaches lignin without degrading cellulose fibres, preserving paper strength while achieving high brightness targets.

ClO2 is supplied as a stabilised aqueous solution or generated on-site from precursor chemicals, with grades available to meet REACH registration requirements and food-contact standards. Procurement teams should confirm solution concentration, generation method, and applicable regulatory documentation prior to sourcing.