Selective dry removal of mercury from waste gases

Besides the amalgamation of gaseous mercury on metal-covered carriers the chemisorptive bonding of mercury on substrates impregnated with metal salt is another possibility to remove mercury selectively from waste gases. Therefore, the dry deposition of mercury was investigated in a laboratory set-up. Several parameters were varied such as the mercury concentration in the gas flow, the temperature and the flow velocity of the gas. The concentration of mercury can be measured quasi-continuously by AAS cold-vapour technique. It turned out that the experimental results of sorption correlate to a high degree with the calculated reaction-enthalpies so that this reaction may be called a selective chemisorption between the mercury in the waste gas current and the metal salt of the substrate material. The thermal desorption of mercury is also successful so that the carrier is able to sorb mercury again without noticeable loss of activity. Therefore, it is to be supposed that this method is qualified as a mercury-recycling procedure.