Replacing dichromate with hydrogen peroxide in the chemical oxygen demand (COD) test.
The widely used standard method for chemical oxygen demand (COD) involves hazardous chromium species, and its two-hour heating protocol entails a substantial amount of energy expenditure. In the present work we report a proof of concept for a major modification of this method in the range 10-800 mgCOD/L, whereby H2O2 is proposed as a replacement oxidizer. This modification not only reduces the use of unsafe chromium species but also allows for the use of milder conditions that decrease the total energy outlay. The results are comparable with those obtained either with the standard method or with a commercial Hach® kit.
Centro Conjunto de Investigacion en Quimica Sustentable UAEMex-UNAM, Carretera Toluca-Atlacomulco Km 14.5, 50200 Toluca, Mexico.
Patricia
P
Carbajal-Palacios
Patricia
P
Balderas-Hernández
Jorge G
JG
Ibanez
Gabriela
G
Roa-Morales
D002623:Chemistry Techniques, Analytical / Q000379:methods*; D017608:Chromium Compounds / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D009930:Organic Chemicals / Q000032:analysis; D010100:Oxygen / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D017608:Chromium Compounds; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D010100:Oxygen