Element doping of biochars enhances catalysis of trichloroethylene dechlorination
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Element doping of biochars enhances catalysis of trichloroethylene dechlorination. / Ma, Hui; Ai, Jing; Lu, Changyong; Hansen, Hans Christian Bruun.
In: Chemical Engineering Journal, Vol. 428, 132496, 2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Element doping of biochars enhances catalysis of trichloroethylene dechlorination
AU - Ma, Hui
AU - Ai, Jing
AU - Lu, Changyong
AU - Hansen, Hans Christian Bruun
N1 - Publisher Copyright: © 2021 The Author(s)
PY - 2022
Y1 - 2022
N2 - Biochar (BC) is used for reductive dehalogenation and detoxification of chlorinated ethylenes, and its catalytic reactivity strongly depends on the type and composition of the biomass. This study aimed to alter the catalytic activity of biochar by using chemical amendments as an alternative to biomass feedstock screening. Three types of amendments including nonmetal elements (urea for N, sodium dodecyl sulfate for S), transition metal elements (MnSO4 for Mn, FeSO4 for Fe), and alkali/alkaline-earth metal elements (CaCl2 for Ca, NaCl for Na) were added to biomass substrate (peanut shell) before pyrolysis at 950 °C to produce 6 different chemically amended BCs. Structure, functional groups, sorption and redox properties of the BCs were characterized, and the catalytic reactivity of the BCs for trichloroethylene (TCE) reduction with a layered iron (II, III) hydroxide (green rust) as reductant was tested. Amending BC with transition metals increased the specific surface area (SSA) of BC and in turn the adsorption affinity, while nonmetals and alkali/alkaline-earth metal amendments decreased SSA. The TCE dechlorination rate increased by 3.5 and 2.5 times for BCs amended with N and S, respectively, compared with Raw-BC, while amendments with Mn, Fe, Ca, and Na had minor effects on reactivity. A second-order kinetic model for TCE reduction was developed, pointing out the critical role of the BC reactive site concentration and competing adsorption of TCE to inreactive surfaces. A conceptual model is proposed for TCE reaction with reactive sites and inreactive adsorptive surfaces on BC. This study suggested demonstrates that the reactive sites density is critical for BC catalytic reactivity, and N amendment is most efficient for improving BC reactivity.
AB - Biochar (BC) is used for reductive dehalogenation and detoxification of chlorinated ethylenes, and its catalytic reactivity strongly depends on the type and composition of the biomass. This study aimed to alter the catalytic activity of biochar by using chemical amendments as an alternative to biomass feedstock screening. Three types of amendments including nonmetal elements (urea for N, sodium dodecyl sulfate for S), transition metal elements (MnSO4 for Mn, FeSO4 for Fe), and alkali/alkaline-earth metal elements (CaCl2 for Ca, NaCl for Na) were added to biomass substrate (peanut shell) before pyrolysis at 950 °C to produce 6 different chemically amended BCs. Structure, functional groups, sorption and redox properties of the BCs were characterized, and the catalytic reactivity of the BCs for trichloroethylene (TCE) reduction with a layered iron (II, III) hydroxide (green rust) as reductant was tested. Amending BC with transition metals increased the specific surface area (SSA) of BC and in turn the adsorption affinity, while nonmetals and alkali/alkaline-earth metal amendments decreased SSA. The TCE dechlorination rate increased by 3.5 and 2.5 times for BCs amended with N and S, respectively, compared with Raw-BC, while amendments with Mn, Fe, Ca, and Na had minor effects on reactivity. A second-order kinetic model for TCE reduction was developed, pointing out the critical role of the BC reactive site concentration and competing adsorption of TCE to inreactive surfaces. A conceptual model is proposed for TCE reaction with reactive sites and inreactive adsorptive surfaces on BC. This study suggested demonstrates that the reactive sites density is critical for BC catalytic reactivity, and N amendment is most efficient for improving BC reactivity.
KW - Biochar
KW - Chemical amendments
KW - N-doped biochar
KW - Reactivity improvement
KW - Trichloroethylene dechlorination
U2 - 10.1016/j.cej.2021.132496
DO - 10.1016/j.cej.2021.132496
M3 - Journal article
AN - SCOPUS:85115797522
VL - 428
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
SN - 1385-8947
M1 - 132496
ER -
ID: 287115114