Bone Char Mediated Dechlorination of Trichloroethylene by Green Rust
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Bone Char Mediated Dechlorination of Trichloroethylene by Green Rust. / Ai, Jing; Ma, Hui; Tobler, Dominique J.; Mangayayam, Marco C.; Lu, Changyong; van den Berg, Frans W. J.; Yin, Weizhao; Bruun Hansen, Hans Christian.
In: Environmental Science and Technology, Vol. 54, No. 6, 2020, p. 3643-3652.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Bone Char Mediated Dechlorination of Trichloroethylene by Green Rust
AU - Ai, Jing
AU - Ma, Hui
AU - Tobler, Dominique J.
AU - Mangayayam, Marco C.
AU - Lu, Changyong
AU - van den Berg, Frans W. J.
AU - Yin, Weizhao
AU - Bruun Hansen, Hans Christian
PY - 2020
Y1 - 2020
N2 - Biochars function as electron transfer mediators and thus catalyze redox transformations of environmental pollutants. A previous study has shown that bone char (BC) has high catalytic activity for reduction of chlorinated ethylenes using layered Fe(II)-Fe(III) hydroxide (green rust) as reductant. In the present study, we studied the rate of trichloroethylene (TCE) reduction by green rust in the presence of BCs obtained at pyrolysis temperatures (PTs) from 450 to 1050 C. The reactivity increased with PT, yielding a maximum pseudo-first-order rate constant (k) of 2.0 h-1 in the presence of BC pyrolyzed at 950 C, while no reaction was seen for BC pyrolyzed at 450 C. TCE sorption, specific surface area, extent of graphitization, carbon content, and aromaticity of the BCs also increased with PT. The electron-accepting capacity (EAC) of BC peaked at PT of 850 C, and EAC was linearly correlated with the sum of concentrations of quinoid, quaternary N, and pyridine-N-oxide groups measured by XPS. Moreover, no TCE reduction was seen with graphene nanoparticles and graphitized carbon black, which have high degrees of graphitization but low EAC values. Further analyses showed that TCE reduction rates are well correlated with the EAC and the C/H ratio (proxy of electrical conductivity) of the BCs, strongly indicating that both electron-accepting functional groups and electron-conducting domains are crucial for the BC catalytic reactivity. The present study delineates conditions for designing redox-reactive biochars to be used for remediation of sites contaminated with chlorinated solvents.
AB - Biochars function as electron transfer mediators and thus catalyze redox transformations of environmental pollutants. A previous study has shown that bone char (BC) has high catalytic activity for reduction of chlorinated ethylenes using layered Fe(II)-Fe(III) hydroxide (green rust) as reductant. In the present study, we studied the rate of trichloroethylene (TCE) reduction by green rust in the presence of BCs obtained at pyrolysis temperatures (PTs) from 450 to 1050 C. The reactivity increased with PT, yielding a maximum pseudo-first-order rate constant (k) of 2.0 h-1 in the presence of BC pyrolyzed at 950 C, while no reaction was seen for BC pyrolyzed at 450 C. TCE sorption, specific surface area, extent of graphitization, carbon content, and aromaticity of the BCs also increased with PT. The electron-accepting capacity (EAC) of BC peaked at PT of 850 C, and EAC was linearly correlated with the sum of concentrations of quinoid, quaternary N, and pyridine-N-oxide groups measured by XPS. Moreover, no TCE reduction was seen with graphene nanoparticles and graphitized carbon black, which have high degrees of graphitization but low EAC values. Further analyses showed that TCE reduction rates are well correlated with the EAC and the C/H ratio (proxy of electrical conductivity) of the BCs, strongly indicating that both electron-accepting functional groups and electron-conducting domains are crucial for the BC catalytic reactivity. The present study delineates conditions for designing redox-reactive biochars to be used for remediation of sites contaminated with chlorinated solvents.
U2 - 10.1021/acs.est.9b07069
DO - 10.1021/acs.est.9b07069
M3 - Journal article
C2 - 32106669
AN - SCOPUS:85081678088
VL - 54
SP - 3643
EP - 3652
JO - Environmental Science & Technology
JF - Environmental Science & Technology
SN - 0013-936X
IS - 6
ER -
ID: 240010682