TY - JOUR
T1 - Stoichiometric carbocatalysis via epoxide-like C−S−O configuration on sulfur-doped biochar for environmental remediation
AU - Wan, Zhonghao
AU - Xu, Zibo
AU - Sun, Yuqing
AU - Zhang, Qiaozhi
AU - Hou, Deyi
AU - Gao, Bin
AU - Khan, Eakalak
AU - Graham, Nigel J.D.
AU - Tsang, Daniel C.W.
N1 - Funding Information:
The authors appreciate the financial support from the Hong Kong Research Grants Council ( PolyU 15222020 ) and Hong Kong Green Tech Fund ( GTF202020153 ). The support from the University Research Facility on Chemical and Environmental Analysis (UCEA) of PolyU is also gratefully acknowledged.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/4/15
Y1 - 2022/4/15
N2 - Heteroatom doping is a promising technique to enhance biochar for effective environmental remediation. However, development of electroactive heteroatom-doped biochars, e.g., sulfur-doped biochar, has been hindered due to complex nature of non-stoichiometric biomass-derived carbon and changeable electrochemical state of dopants. Herein, we produced a series of wood waste-derived biochars with customized levels of minerals and redox-active moieties, aiming to unravel the crucial factors for sulfur doping. Calcium (Ca) in biochar was found to preferentially coordinate with sulfur to form inactive inorganic sulfur minerals (i.e., CaSO4 and CaS) with inferior catalytic reactivity. After diminishing the inherent Ca minerals beforehand, we could introduce surface phenoxyl-type radicals (C−O•) and vacancy defects on the biochar to develop an electrophilic C−S−O bonding configuration, which guaranteed a high affinity towards peroxymonosulfate (PMS, 2.08 mM g−1, 30 min) and efficient removal of bisphenol A (BPA, 91.1%, 30 min). Scavenging experiments and in-situ Raman analyses indicated that the epoxide-like C−S−O structure induced nucleophilic addition of PMS to generate surface-bound singlet oxygen (1O2, major) and hydroxyl radicals (•OH, minor) through a preservative and stoichiometric interfacial reaction. Overall, the proposed approach overcomes the major hurdles in science-informed fabrication of sulfur-doped biochar and advances its development for environmental remediation.
AB - Heteroatom doping is a promising technique to enhance biochar for effective environmental remediation. However, development of electroactive heteroatom-doped biochars, e.g., sulfur-doped biochar, has been hindered due to complex nature of non-stoichiometric biomass-derived carbon and changeable electrochemical state of dopants. Herein, we produced a series of wood waste-derived biochars with customized levels of minerals and redox-active moieties, aiming to unravel the crucial factors for sulfur doping. Calcium (Ca) in biochar was found to preferentially coordinate with sulfur to form inactive inorganic sulfur minerals (i.e., CaSO4 and CaS) with inferior catalytic reactivity. After diminishing the inherent Ca minerals beforehand, we could introduce surface phenoxyl-type radicals (C−O•) and vacancy defects on the biochar to develop an electrophilic C−S−O bonding configuration, which guaranteed a high affinity towards peroxymonosulfate (PMS, 2.08 mM g−1, 30 min) and efficient removal of bisphenol A (BPA, 91.1%, 30 min). Scavenging experiments and in-situ Raman analyses indicated that the epoxide-like C−S−O structure induced nucleophilic addition of PMS to generate surface-bound singlet oxygen (1O2, major) and hydroxyl radicals (•OH, minor) through a preservative and stoichiometric interfacial reaction. Overall, the proposed approach overcomes the major hurdles in science-informed fabrication of sulfur-doped biochar and advances its development for environmental remediation.
KW - Biomass valorization
KW - Engineered biochar catalyst
KW - Heteroatom doping
KW - Persulfate activation
KW - Sustainable waste management
KW - Wastewater treatment
UR - http://www.scopus.com/inward/record.url?scp=85122948576&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2022.128223
DO - 10.1016/j.jhazmat.2022.128223
M3 - Journal article
AN - SCOPUS:85122948576
SN - 0304-3894
VL - 428
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 128223
ER -