Dripping Wet Water, Incorporated has found a way to take the hassle out of conventional chlorine dioxide generation equipment. Our ClO₂IX^® Generators use no chemical mixing chemistries and no electrochemical cassettes in their designs. The ClO₂IX^® Generators can dose directly into pressurized lines, and operators don’t have to worry about high concentration solutions or chlorinated byproducts. Does this sound too good to be true? Let’s see.

The Dripping Wet Water ClO₂IX^® Generators incorporate reliable, proven components and technologies to take advantage of chlorine dioxide’s unique properties. In our design, we start with Step 1.

STEP 1: CHLOROUS ACID
No matter how you make chlorine dioxide, you must first start with chlorous acid. Chlorous acid is a simple compound that occurs when the sodium (Na+) ion in sodium chlorite (NaClO₂) is replaced with hydrogen (H+) ion. The resultant compound, chlorous acid (HClO₂), is the real precursor for the formation of chlorine dioxide (ClO₂), and its formation is shown in Reaction (1).

Na+ClO₂- + H+ → H+ClO₂- + Na+ (1)

In traditional technologies, H+ is added to the sodium chlorite in high concentrations by mixing acid to encourage the displacement of Na+ with H+, thus promoting the formation of chlorous acid. However, given that the sodium remains in solution, the equilibrium of the reaction cannot be shifted entirely to chlorous acid, unless a large excess of acid is added. Therefore, under normal circumstances, a mixed solution exists, as is shown in Reaction (1).  The inability of Reaction (1) to go to completion inhibits the further formation of chlorine dioxide by limiting the amount of chlorous acid available, especially in dilute solutions or if a weak acid is used.

Dripping Wet Water has found a way, however, to form a solution of chlorous acid without residual Na+. By using cation exchange resin in the H+ form, we are able to remove the Na+ from the sodium chlorite (Na+ClO₂-) and replace it with H+ to form pure chlorous acid (H+ClO₂-). When the cation resin is exhausted, i.e. all of the cationic sites are in the Na+ form, the resin must be replaced or regenerated with a hydrogen source. Regeneration  may take place either on-site or off-site, depending upon the conditions of the application.  ClO₂IX^® Generators use hydrochloric acid (HCl) for regeneration, because this acid is commonly used in the commercial and small industrial water treatment industry.

It is important to remember that the acid used during regeneration does not enter into the production of chlorous acid and never contacts the sodium chlorite.  The acid is merely used as a hydrogen source for the regeneration of the cation exchange resin.

By starting with a pure precursor, Dripping Wet Water increases reaction efficiency, but the reaction of chlorous acid to chlorine dioxide is not
instantaneous...until Step 2.

STEP 2: CHLORINE DIOXIDE
As is shown in the following reactions, once chlorous acid is formed, the reaction to chlorine dioxide may proceed in one of three ways: via the decomposition or chlorous acid to chlorine dioxide, via the disproportionation of chlorous acid to chlorine dioxide or via the oxidation of chlorous acid to chlorine dioxide.

4 HClO₂ → 2 ClO₂ + HCl + HClO₃ + H₂O (2)      or
5 HClO₂ + HCl → 4 ClO₂ + 2 HCl + 2 H₂O (3)    or
HClO₂ - e- → ClO₂ + H+ (4)

Reaction (2) is extremely time and concentration dependent, Reaction (3) requires high concentration precursors and excess HCl,  and Reaction (4) often yields unwanted byproducts such as chlorine or ozone from the addition of chlorine or from electrochemical oxidation.  Given the slow reaction times, lack of safety and the expensive capital required for these technologies, these processes have had limited success in the commercial and small industrial markets.

Dripping Wet Water has found a way to generate chlorine dioxide from chlorous acid without chlorine or excess acid, without chemical mixing,
without electrochemisty, and without residual chlorite in the chlorine dioxide product stream. By utilizing catalytic technology in our Conversion Cartridge, we can convert virtually all of the chlorous acid to chlorine dioxide via Reaction (3) instantaneously and in dilute solution without HCl.  This means that there is virtually no chlorite residual in the chlorine dioxide product, and there is no storage of chlorine dioxide required.  In fact, you can dose the chlorine dioxide proportionally into the process water.  Further, since the ClO₂IX^® Generators can operate under pressure, the chlorine dioxide product can be dosed directly into a pressurized line without the need of an additional booster pump. Best of all, however, is that all of this occurs with safe chlorine dioxide concentrations of less than 700 mg/L.

If you have wanted to use chlorine dioxide but have been afraid due to the generation methods available to you, now is the time to conquer your fears with Dripping Wet Water. If you are a chlorine dioxide user but are frustrated with the complexity, lack of performance, and high cost of what you are using, give us a try.

You’ll never go back!