Gas-phase elemental mercury removal using ammonium chloride impregnated sargassum chars.

In this article, pyrolyzed bio-chars derived from a kind of macroalgae, sargassum, were modified by ammonium chloride (NH₄Cl) impregnation, and were applied to remove Hg⁰ from flue gas. The characteristics of sorbents were investigated by the Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy, scanning electron microscopy and ultimate and proximate analysis. The key parameters (e.g. loading value, reaction temperature and concentration of O₂, NO, SO₂ and water vapor), kinetics analysis and reaction mechanism of Hg⁰ removal were investigated. The results show that increasing loading value, reaction temperature, O₂ concentration and NO concentration enhance Hg⁰ removal. The increase in SO₂ concentration or water vapor concentration has a dual effect on Hg⁰ removal. The C–Cl groups and C=O groups play an important role in the process of Hg⁰ removal. The Hg⁰ removal process of modified samples meets the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]