title: Removal of element mercury by medicine residue derived biochars in presence of various gas compositions.
abstract: Pyrolyzed biochars from an industrial medicinal residue waste were modified by microwave activation and NH4Cl impregnation. Mercury adsorption of different modified biochars was investigated in a quartz fixed-bed reactor. The results indicated that both physisorption and chemisorption of Hg(0) occurred on the surface of M6WN5 which was modified both microwave and 5wt.% NH4Cl loading, and exothermic chemisorption process was a dominant route for Hg(0) removal. Microwave activation improved pore properties and NH4Cl impregnation introduced good active sites for biochars. The presence of NO and O2 increased Hg(0) adsorption whereas H2O inhibited Hg(0) adsorption greatly. A converse effect of SO2 was observed on Hg(0) removal, namely, low concentration of SO2 promoted Hg(0) removal obviously whereas high concentration of SO2 suppressed Hg(0) removal. The Hg(0) removal by M6WN5 was mainly due to the reaction of the C−Cl with Hg(0) to form HgCl2, and the active state of C−Cl(*) groups might be an intermediate group in this process. Thermodynamic analysis showed that mercury adsorption by the biochars was exothermic process and apparent adsorption energy was 43.3 kJ/mol in the range of chemisorption. In spite of low specific surface area, M6WN5 proved to be a promising Hg(0) sorbent in flue gas when compared with other sorbents.
authors.affiliation: School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China; College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Li
authors.affiliation: School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China; College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. Electronic address: shenbx@nankai.edu.cn.
authors.forename: Boxiong
authors.initials: B
authors.lastname: Shen
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yongwang
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Chemical Engineering, Hebei University of Technology, Tianjin 300401, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhao
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Fumei
authors.initials: F
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: He
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yinyin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D000643:Ammonium Chloride / Q000737:chemistry; D002606:Charcoal; D004350:Drug Residues / Q000737:chemistry*; D005740:Gases; D008506:Medical Waste / Q000032:analysis*; D008628:Mercury / Q000302:isolation & purification*; D008872:Microwaves; D009569:Nitric Oxide / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D013458:Sulfur Dioxide / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics
chemical_list: D005740:Gases; D008506:Medical Waste; C540010:biochar; D000643:Ammonium Chloride; D013458:Sulfur Dioxide; D002606:Charcoal; D009569:Nitric Oxide; D008628:Mercury; D010100:Oxygen
keywords: Adsorbents; Biochars; Elemental mercury removal; Medicinal residue waste; Microwave activation; NH(4)Cl impregnation