Mercury oxidation coupled to autotrophic denitrifying branched sulfur oxidation and sulfur disproportionation for simult
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ENVIRONMENTAL BIOTECHNOLOGY
Mercury oxidation coupled to autotrophic denitrifying branched sulfur oxidation and sulfur disproportionation for simultaneous removal of Hg0 and NO Zhenshan Huang 1 & X. Q. Tan 2 & Z. S. Wei 1 & H. Y. Jiao 1 & X. L. Xiao 1 & S. Ming 1 Received: 13 May 2020 / Revised: 10 July 2020 / Accepted: 11 August 2020 / Published online: 18 August 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Coupling elemental mercury (Hg0) oxidation, autotrophic denitrifying sulfur oxidation, and sulfur disproportionation offers technological potential for simultaneous Hg0 and nitric oxide (NO) removal. This study shed light on simultaneous demercuration and denitration of flue gas by a sulfur-oxidizing membrane biofilm reactor (MBfR). Removal efficiency of Hg0 and NO attained 92% and 83%, respectively in long-term operation. Taxonomic and metagenomic study revealed that a tremendous variety of Hg0-oxidizing bacteria (MOB) (Thiobacillus, Truepera, etc.), denitrifying/sulfur-oxidizing bacteria (DSOB) (Thioalkalivibrio, Thauera, etc.), sulfurdisproportionating bacteria (SDB) (Desulfobulbus, Desulfomicrobium, etc.), and multi-functional bacteria (Halothiobacillus, Thiobacillus, etc.) significantly increased in abundance during growth under feeding of Hg0 and NO in simulated flue gas. The comprehensive employment of sequential chemical extraction processes, inductive coupled mass spectrometry, X-ray diffraction, Xray photoelectron spectroscopy, and scanning electron microscopy coupled to energy disperse spectroscopy confirmed that Hg0 was finally biologically oxidized to crystallized metacinnabar (β-HgS) extracellular micromolecular particles. Our findings provided mechanistic insights that MOB, DSOB, and multi-functional bacteria synergistically bio-oxidized Hg0 as the initial electron donor to Hg2+ and denitrified NO as the terminal electron acceptor to N2. SDB disproportionated S0 branched from S2O32− into S2− and SO42 − , and β-HgS formation from Hg2+ and disproportionation-derived S2−, thermodynamically favored Hg0 bio-oxidation. This novel biotechnique can be a cost-effective and environmentally friendly alternative to flue gas Hg0 and NO treatment. Key points • Combination of Hg0 bio-oxidation and autotrophic denitrifying sulfur oxidation achieved simultaneous Hg0 and NO removal. • Thiosulfate disproportionation reinforced Hg0 bio-oxidation for Hg0 removal. • Mercury-oxidizing bacteria, denitrifying/sulfur-oxidizing bacteria, and sulfur-disproportionating bacteria synergistically accomplished Hg0 and NO removal. Keywords Hg0 bio-oxidation . Sulfur oxidation . Autotrophic denitrification . Sulfur disproportionation . Simultaneous Hg0 and NO removal
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00253-020-10827-1) contains supplementary material, which is available to authorized users. * Z. S. Wei [email protected] 1
Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environ
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