Fast and stable real time monitoring of gaseous mercury in its catalytic oxidation using a fully modified cold-vapor atomic absorption mercury analyzer

A commercially-available cold-vapor atomic absorption mercury analyzer had many difficulties in monitoring real-time gaseous mercury (Hg-0) in its oxidation over a V2O5/TiO2-based catalyst under conditions additionally containing HCl, NO and NH3. Thus we made extensive modifications to the original analyzer so that this is suitable for fast and stable real-time Hg-0 detections even at low sample flow rates as well as at the harsh conditions. Our fully modified analyzer gave Hg-0 signals very similar to those based upon the factory-certified permeation rate of the mercury permeation tube. Gaseous Hg-0 could react, only to a small extent, with HCl over a quartz powder and the measured Hg-0 oxidation activity was almost associated with the catalyst depending on concentrations of HCl fed to gas streams with NO and NH3. This study can offer useful solutions to academic and industrial research groups to attempt real-time Hg-0 measurements at such chosen conditions.

Automated summary

Extensive modifications were made to a commercially-available cold-vapor atomic absorption mercury analyzer to enable fast and stable real-time Hg-0 detection under harsh conditions with additional HCl, NO, and NH3. The fully modified analyzer showed similar Hg-0 signals to those based on factory-certified permeation tubes. The oxidation activity of gaseous Hg-0 was found to be associated with the catalyst and influenced by the concentration of HCl in gas streams with NO and NH3.