Bio-oxidation of Elemental Mercury into Mercury Sulfide and Humic Acid-Bound Mercury by Sulfate Reduction for Hg0 Removal in Flue Gas

• DOI: 10.1021/acs.est.9b04029
• Publication Date: 2019-10-07T13:03:01Z
• Authors: Zhenshan Huang; Zaishan Wei; Xiaoliang Xiao; Meiru Tang; Bailong Li; Song Ming; Xiangling Cheng
• Keywords: Mercury; Elemental mercury

Bioconversion of elemental mercury (Hg0) into immobile, nontoxic, and less bioavailable species is vital environmental significance. Here, we investigated bioconversion Hg0 in a sulfate-reducing membrane biofilm reactor (MBfR). The MBfR achieved effective removal by sulfate bioreduction. 16 S rDNA sequencing metagenomic revealed that diverse groups mercury-oxidizing/sulfate-reducing bacteria (Desulfobulbus, Desulfuromonas, Desulfomicrobium, etc.) utilized as the initial electron donor terminal acceptor to form overall redox. These microorganisms coupled bio-oxidation Analysis on speciation sequential extraction processes (SEPs) inductively mass spectrometry (ICP-MS) temperature programmed desorption (Hg-TPD) showed sulfide (HgS) humic acid-bound (HA-Hg) were two major products bio-oxidation. With HgS HA-Hg comprehensively characterized X-ray diffraction (XRD), excitation-emission matrix spectra (EEM), scanning microscopy-energy disperse spectroscopy (SEM-EDS), photoelectron (XPS), Fourier transform infrared (FTIR), it was proposed biologically oxidized (Hg2+) further reacted with biogenic sulfides cubically crystallized metacinnabar (β-HgS) extracellular particles. Hg2+ also complexed functional −SH, −OH, −NH–, −COO– acids from polymeric substances (EPS) HA-Hg. may react HgS. therefore can be feasible biotechnique for flue gas demercuration.