TY - JOUR

T1 - Biochar catalyzed dechlorination – Which biochar properties matter?

AU - Ai, Jing

AU - Lu, Changyong

AU - van den Berg, Frans W. J.

AU - Yin, Weizhao

AU - Strobel, Bjarne W.

AU - Hansen, Hans Christian B.

PY - 2021

Y1 - 2021

N2 - Bone char catalyzed dechlorination of trichloroethylene (TCE) by green rust (iron(II)-iron(III) hydroxide, GR) has introduced a promising new reaction platform for degradation of chlorinated solvents. This study aimed to reveal whether a broader class of biochars are catalytically active for the dechlorination reaction and to identify which biochar properties are the most important for the catalytic activity. Biochars produced by pyrolysis of animal, plant, and sewage waste substrates at 950 °C were prepared for catalytic dechlorination of TCE by GR tested in batch experiments with 0.15 g L−1 biochar, 3.2 g L−1 GR, and ~ 20 µM TCE. The results showed that the biochar substrate significantly affects its catalytic activity, with the highest TCE reduction rate observed for bone and shrimp-based biochars (k ≥ 0.18 h−1), whereas no reactivity was seen for graphite and activated carbon references. Multivariate regression indicated that the biochar catalytic activity is controlled by multiple biochar properties - biochar surface area, TCE sorption, abundance of C–O groups, and pore size are the properties that impact the catalytic activity most. Derivation of biochar reactivity relationship for a broad spectrum of biochars provides a new approach for identifying proper biochar catalysts for pollutant degradation.

AB - Bone char catalyzed dechlorination of trichloroethylene (TCE) by green rust (iron(II)-iron(III) hydroxide, GR) has introduced a promising new reaction platform for degradation of chlorinated solvents. This study aimed to reveal whether a broader class of biochars are catalytically active for the dechlorination reaction and to identify which biochar properties are the most important for the catalytic activity. Biochars produced by pyrolysis of animal, plant, and sewage waste substrates at 950 °C were prepared for catalytic dechlorination of TCE by GR tested in batch experiments with 0.15 g L−1 biochar, 3.2 g L−1 GR, and ~ 20 µM TCE. The results showed that the biochar substrate significantly affects its catalytic activity, with the highest TCE reduction rate observed for bone and shrimp-based biochars (k ≥ 0.18 h−1), whereas no reactivity was seen for graphite and activated carbon references. Multivariate regression indicated that the biochar catalytic activity is controlled by multiple biochar properties - biochar surface area, TCE sorption, abundance of C–O groups, and pore size are the properties that impact the catalytic activity most. Derivation of biochar reactivity relationship for a broad spectrum of biochars provides a new approach for identifying proper biochar catalysts for pollutant degradation.

KW - Black carbon

KW - Catalytic activity

KW - Chlorinated solvents

KW - Dehalogenation

KW - Remediation

U2 - 10.1016/j.jhazmat.2020.124724

DO - 10.1016/j.jhazmat.2020.124724

M3 - Journal article

C2 - 33307445

AN - SCOPUS:85098457715

VL - 406

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

M1 - 124724

ER -