Determination of Adsorbable Organic Halogen (AOX) in Wastewater Using Combustion Ion Chromatography

Changing the Paradigm for Water Pollution Monitoring
Oral Presentation

Presented by K. Chassaniol
Prepared by , J. Rohrer

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Organohalogens are toxic and persistent and thus they have often been given high priority in the monitoring and control of environmental pollution. Adsorbable organically bound halogens (AOX) are a group of chemicals which can be adsorbed from water onto activated carbon. The challenge is then to remove and measure these compounds. One approach is automated combustion ion chromatography (CIC). In CIC, an activated carbon sample with adsorbed halogen-containing compounds is combusted and the resultant gas is released into an absorption solution, which is then loaded directly for ion chromatography (IC). This paper shows that AOX can be precisely and accurately determined in wastewater using CIC with a Mitsubishi AQF-2100H combustion system in combination with a Dionex Integrion high-pressure ion chromatography system. Analytes from combustions were separated with a Dionex IonPac AS18 4┬Ám column using KOH automatically generated by the IC system. In contrast to the AOX analysis method where only the sum of organic halogens is measured by amperometric titration, the reported CIC method provides that sum and halogen speciation, including information about the adsorbable organic fluorine.