A review on oxidation of elemental mercury from coal-fired flue gas with selective catalytic reduction catalysts

Abstract

Catalytic technologies present a more environmentally and financially sound option in the removal of elemental mercury (Hg⁰) from coal-fired flue gas. However, developing novel and efficient catalysts for Hg⁰ oxidation is still a challenge. This paper reviews the catalytic oxidation of Hg⁰ over a new kind of catalysts which were developed from selective catalytic reduction (SCR) catalysts of NO_x. In this review, both noble metal catalysts and non-noble metal catalysts for Hg⁰ oxidation were summarized. An overview of mercury emissions including transformation and speciation of mercury in coal-fired flue gas was also presented. The possible mechanisms and kinetics of mercury oxidation, space velocity and the effects of flue gas components on activity and stability of the catalysts were examined. We expect that this work will serve as a theoretical underpinning for the development of Hg⁰ oxidation technology in flue gas.