Release behavior of Hg captured on V₂O₅/AC during the regeneration process

The release behavior of Hg captured on V₂O₅/AC during regeneration and temperature programmed desorption (TPD) processes was studied. The Hg⁰ capture capability of the regenerated V₂O₅/AC was also tested. It was found that 81% or 94% of Hg captured on V₂O₅/AC can be released during the thermal (Ar, 400℃) or NH₃ (NH₃/Ar, 300℃) regeneration processes. The released Hg is mainly in the form of Hg⁰ due to the reduction activity of carbon in AC. The TPD-AFS profile reveals that the release behavior of Hg under Ar and NH₃/Ar atmospheres is different. NH₃ in the atmosphere improved the release of Hg by lowering the highest release temperature to 300℃. Under pure Ar atmosphere the release of Hg still can be observed above 400℃. It caused the difference in Hg release ratio respect with the two regeneration processes tested. However, when NH₃ concentration increases from 1% to 5% or higher the Hg release ratio is unchanged. If the higher regeneration temperature was used the difference in Hg release ratio during the two regeneration processes should vanish. Regeneration methods have slight effects on Hg⁰ capture capability on V₂O₅/AC. The Hg⁰ capture capability of regenerated V₂O₅/AC under the two processes is similar, which is lower than that of the fresh V₂O₅/AC but still much higher than that of AC.