title: Reduction of Bromate by Cobalt-Impregnated Biochar Fabricated via Pyrolysis of Lignin Using CO2as a Reaction Medium.
abstract: In this study, pyrolysis of lignin impregnated with cobalt (Co) was conducted to fabricate a Co-biochar (i.e., Co/lignin biochar) for use as a catalyst for bromate (BrO3-) reduction. Carbon dioxide (CO2) was employed as a reaction medium in the pyrolysis to induce desired effects associated with CO2; (1) the enhanced thermal cracking of volatile organic compounds (VOCs) evolved from the thermal degradation of biomass, and (2) the direct reaction between CO2and VOCs, which resulted in the enhanced generation of syngas (i.e., H2and CO). This study placed main emphases on three parts: (1) the role of impregnated Co in pyrolysis of lignin in the presence of CO2, (2) the characterization of Co/lignin biochar, and (3) evaluation of catalytic capability of Co-lignin biochar in BrO3-reduction. The findings from the pyrolysis experiments strongly evidenced that the desired CO2effects were strengthened due to catalytic effect of impregnated Co in lignin. For example, the enhanced generation of syngas from pyrolysis of Coimpregnated lignin in CO2was more significant than the case without Co impregnation. Moreover, pyrolysis of Coimpregnated lignin in CO2led to production of biochar of which surface area (599 m2g-1) is nearly 100 times greater than the biochar produced in N2(6.6 m2g-1). Co/lignin biochar produced in CO2also showed a great performance in catalyzing BrO3-reduction as compared to the biochar produced in N2.
authors.affiliation: Department of Environment and Energy, Sejong University , Seoul 05006, South Korea.
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Cho
authors.affiliation: Department of Environment and Energy, Sejong University , Seoul 05006, South Korea.
authors.forename: Gihoon
authors.initials: G
authors.lastname: Kwon
authors.affiliation: School of Natural Resources and Environmental Science & Korea Biochar Research Center, Kangwon National University , Chuncheon 24341, South Korea.
authors.forename: Yong Sik
authors.identifier: http://orcid.org/0000-0003-3401-0912
authors.initials: YS
authors.lastname: Ok
authors.affiliation: Department of Environment and Energy, Sejong University , Seoul 05006, South Korea.
authors.forename: Eilhann E
authors.initials: EE
authors.lastname: Kwon
authors.affiliation: Department of Environment and Energy, Sejong University , Seoul 05006, South Korea.
authors.forename: Hocheol
authors.identifier: http://orcid.org/0000-0002-3951-4901
authors.initials: H
authors.lastname: Song
keywords: bromate reduction; carbon dioxide; engineered biochar; lignin; pyrolysis; waste-to-energy