期刊
CHEMICAL ENGINEERING JOURNAL
卷 432, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2021.134440
关键词
Elemental mercury; Flue gas; Biochar; Heteroatom doping; Phosphorus; Pyrolysis
资金
- National Natural Science Foundation of China [52106168, U20A20115]
- Shandong Province Key Research and Development Project [2019GSF109097]
- Guangdong Basic and Applied Basic Research Foundation [2020A1515111197]
- Natural Science Foundation of Shandong Province [ZR2020QE202]
- China Postdoctoral Science Foundation [2020M682179]
- Youth Innovation Program of Universities in Shandong Province [2019KJD007]
Phosphorus-doped biochars (PBCs) derived from one-step pyrolysis of H3PO4-laden biomass showed improved mercury removal efficiency and surface area. The chemisorption mechanism involving electron transfer was responsible for the enhanced Hg-0 oxidation.
Heteroatom doping is an effective method to modify carbonaceous sorbents and improve their chemical reactivity. In this study, P-doped biochars (PBCs) derived from one-step pyrolysis of H3PO4-laden biomass were developed for elemental mercury (Hg-0) removal from coal-fired flue gas. Sample characterization showed that there were massive micropores and slit-shaped mesoporous in the PBCs. The specific surface area and pore volume of PBCs was obviously enhanced after P doping. In addition, more organic functional groups were generated on the PBCs surface, particularly the C-P=O and C=O groups. The PBCs presented far higher mercury removal efficiency compared with raw biochars (BCs). The influences of pyrolysis temperature (700 ?degrees C-1000 ?degrees C), adsorption temperature (25 ?degrees C-180 ?degrees C), and various flue gas components (NO, SO2, O-2, HCl, and H2O) on mercury removal performance were also analyzed. At the optimum temperature (100 ?degrees C), the Hg-0 adsorption capacity of PBC900 was increased by more than 400 times compared with BC900, which was also higher than that of a commercial brominated activated carbon. The mechanism responsible for Hg-0 removal was further revealed. The results suggested that chemisorption dominated the Hg-0 removal process, where the C-P=O, C=O, and O-C=O groups could serve as electron acceptors, accelerating the electron migration process for Hg-0 oxidization.
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