Oxidation and reduction (redox) reactions are very important in drinking water.
Oxidation-reduction potential (ORP) measurements reflect the redox state of water. Redox
measurements are not widely made by drinking water utilities in part because they are not well
understood. The objective of this study was to determine the effect of oxidant type and
concentration on the ORP of carbonate buffered water as a function of pH. Oxidants that were
studied included: chlorine, monochloramine, potassium permanganate, chlorine dioxide, and
oxygen. ORP decreased with increasing pH, regardless of the oxidant type or concentration.
ORP increased rapidly with increasing oxidant dosage, particularly at lower concentrations.
Differences in the redox potentials of different oxidant systems were also observed. Waters that
contained chlorine and chlorine dioxide had the highest ORPs. Tests also revealed that there
were inconsistencies with redox electrode measurements. In the standard Zobell reference
solution, two identical redox electrodes had nearly the same reading, but in test waters the
readings sometimes showed a variation as great as 217.7 mV. Includes 11 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 11/15/2004 |
