TY - JOUR
T1 - Aging features of metal(loid)s in biochar-amended soil
T2 - Effects of biochar type and aging method
AU - Yang, Xiaodong
AU - Wang, Liuwei
AU - Guo, Jiameng
AU - Wang, Huixia
AU - Mašek, Ondřej
AU - Wang, Hailong
AU - Bolan, Nanthi S
AU - Alessi, Daniel S
AU - Hou, Deyi
PY - 2022/4/1
Y1 - 2022/4/1
N2 - Soil contamination with toxic metals and metalloids has become a major threat to global food security. Among various immobilization agents that can stabilize toxic metal(loid)s effectively, biochar is promising due to its ability to restore soil health. Yet the aging characteristics of biochar following its amendment in soil remain poorly explored. Therefore, this study used standard biochars to depict their aging effects on remediation of metal(loid)-contaminated soil. A total of 2304 observations were made, including 6 biochar feedstocks (rice husk, soft wood, oilseed rape straw, miscanthus straw, sewage sludge and wheat straw), 2 pyrolysis temperatures (550 °C, 700 °C), 8 metal(loid)s (Mn, Ni, Cu, Zn, As, Cd, Sb, Pb), 4 aging methods (natural aging, freeze-thaw cycling, wet-dry cycling, chemical oxidation with H2O2), and 6 sampling intervals. Sewage sludge biochars exhibited the highest resistance to both artificial and natural aging, which may be related to the abundant oxygen-containing functional groups that favor metal complexation, and poorly-developed pore structures that limit the access of natural aging forces. A distinct relationship between ash and temperature was observed, where for high-ash biochars, an increase in pyrolysis temperature indicated lower resistance to aging, while for low-ash biochars, elevated pyrolysis temperature led to higher resistance. The aging behaviors of Cu and Sb were quite similar, which were both highly susceptible to chemical oxidation-induced dissolved organic carbon (DOC) release. Wet-dry cycling and freeze-thaw cycling revealed aging patterns that were similar to those of naturally aged soils as confirmed by cluster analysis. Lab aging data were then compared with existing biochar field aging results. Contrasting long-term immobilization performances were found in different studies, which were attributed to various causes associated with both biochar property and climate. The results of this study provide fresh insights into the long-term risks in the management of metal(loid)-contaminated agricultural soils.
AB - Soil contamination with toxic metals and metalloids has become a major threat to global food security. Among various immobilization agents that can stabilize toxic metal(loid)s effectively, biochar is promising due to its ability to restore soil health. Yet the aging characteristics of biochar following its amendment in soil remain poorly explored. Therefore, this study used standard biochars to depict their aging effects on remediation of metal(loid)-contaminated soil. A total of 2304 observations were made, including 6 biochar feedstocks (rice husk, soft wood, oilseed rape straw, miscanthus straw, sewage sludge and wheat straw), 2 pyrolysis temperatures (550 °C, 700 °C), 8 metal(loid)s (Mn, Ni, Cu, Zn, As, Cd, Sb, Pb), 4 aging methods (natural aging, freeze-thaw cycling, wet-dry cycling, chemical oxidation with H2O2), and 6 sampling intervals. Sewage sludge biochars exhibited the highest resistance to both artificial and natural aging, which may be related to the abundant oxygen-containing functional groups that favor metal complexation, and poorly-developed pore structures that limit the access of natural aging forces. A distinct relationship between ash and temperature was observed, where for high-ash biochars, an increase in pyrolysis temperature indicated lower resistance to aging, while for low-ash biochars, elevated pyrolysis temperature led to higher resistance. The aging behaviors of Cu and Sb were quite similar, which were both highly susceptible to chemical oxidation-induced dissolved organic carbon (DOC) release. Wet-dry cycling and freeze-thaw cycling revealed aging patterns that were similar to those of naturally aged soils as confirmed by cluster analysis. Lab aging data were then compared with existing biochar field aging results. Contrasting long-term immobilization performances were found in different studies, which were attributed to various causes associated with both biochar property and climate. The results of this study provide fresh insights into the long-term risks in the management of metal(loid)-contaminated agricultural soils.
U2 - 10.1016/j.scitotenv.2022.152922
DO - 10.1016/j.scitotenv.2022.152922
M3 - Article
C2 - 34999075
SN - 0048-9697
VL - 815
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 152922
ER -
