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 Hg-0 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 O-2, NO, SO2 and water vapor), kinetics analysis and reaction mechanism of Hg-0 removal were investigated. The results show that increasing loading value, reaction temperature, O-2 concentration and NO concentration enhance Hg-0 removal. The increase in SO2 concentration or water vapor concentration has a dual effect on Hg-0 removal. The C-Cl groups and C=O groups play an important role in the process of Hg-0 removal. The Hg-0 removal process of modified samples meets the pseudo-second-order kinetic model.