Recent developments on gas–solid heterogeneous oxidation removal of elemental mercury from flue gas

Abstract

Mercury is a toxic and persistent environmental pollutant which has been recognized as a global threat to human health and our ecosystem because mercury bio-accumulates in the food chain and can be transformed into the more neurotoxic methylmercury. Among current and emerging abatement technologies for elemental mercury in flue gas, gas–solid heterogeneous oxidation is nowadays gaining increasing attention due to several inherent advantages. The catalysts and adsorbents are key materials that control the heterogeneous catalytic oxidation and adsorption of Hg0 from flue gas. Here we present a review of the recent developments on several catalysts and adsorbents, including noble metal-based catalysts, non-noble metal-based catalysts (transition metal oxides and selective catalytic reduction catalysts), activated carbon/coke-based sorbents, biochar-based sorbents, fly ash-based sorbents, mineral material-based sorbents and other novel catalysts. The key process parameters and kinetic reaction mechanisms and advantages and disadvantages of various emerging catalysts/adsorbents and technologies of Hg0 removal are described in detail.