In yesterday’s posting on this blog we talked briefly about the way ozone reacts with organic compounds in water. This involved the two reaction pathways, either the slower selective molecular ozone pathway or the faster, non selective hydroxyl radical pathway. We recently have been contacted by an engineering firm interested in destroying carbon tetrachloride using ozone. It turns out that neither ozone nor advanced oxidation processes (AOP), those that make hydroxyl radicals, are good choices for this application. Instead, UV radiation alone is the best way to destroy this compound.
Dr. Omar Legrini of our partner company ESCO International (www.escouk.com) offers the following explanation: Carbon-Chlorine (C-Cl) bonds are relatively inert toward potential radical substitution by OH radicals, and therefore per chlorinated compounds are only slowly oxidized by degradation processes relying on OH radicals as the reactive intermediate.
There are published studies that suggest that the AOP UV/ozone can destroy carbon tetrachloride, but Dr. Legrini believes that the effect is simply stripping of the compound from the water during the degassing of the liquid following ozonation. In addition, the UV employed in these systems is not the proper wavelength to effectively break the carbon-halogen bond.
If you have issues with carbon tetrachloride and want to avoid transferring the problem to the air or disposing of activated carbon, please contact Spartan (www.spartanwatertreatment.com/contactus.html).