TY - JOUR
T1 - (Im)mobilization and speciation of lead under dynamic redox conditions in a contaminated soil amended with pine sawdust biochar
AU - Beiyuan, Jingzi
AU - Awad, Yasser M.
AU - Beckers, Felix
AU - Wang, Jianxu
AU - Tsang, Daniel C.W.
AU - Ok, Yong Sik
AU - Wang, Shan Li
AU - Wang, Hailong
AU - Rinklebe, Jörg
N1 - Funding Information:
The authors appreciate the financial support by the National Research Foundation of Korea ( NRF-2015R1A2A2A11001432 ), a Korean University Grant , the National Natural Science Foundation of China ( 21577131 , 21876027 ), and the Natural Science Foundation of Guangdong Province , China ( 2017A030311019 ). We are grateful to the National Synchrotron Radiation Research Center, Taiwan, for the valuable beamtime and the support. The authors thank Mr. C. Vandenhirtz and Mr. Jan Schneider of University of Wuppertal for their technical and experimental assistance. The authors also appreciate Ms Puu-Tai Yang of National Taiwan University for her kind help on Pb XANES analysis. Appendix A
Publisher Copyright:
© 2019 The Authors
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/2
Y1 - 2020/2
N2 - Biochar can reduce the mobility and availability of potentially toxic elements (PTEs) in soils and improve soil properties. However, immobilization efficiencies of biochar can be varied according to environmental conditions, such as pH and redox potential (Eh), especially for soils under flood-dry cycles. In the current study, biochar produced at 300 and 550 °C (referred as BC300 and BC550, respectively) and its feedstock (pine sawdust biomass, BM) were used to amend a lead (Pb)-contaminated soil under pre-defined redox windows (from −300 to +250 mV). Key features of the soil-solution were evaluated in detail, including pH, dissolved organic carbon, sulphate, and dissolved Al, Fe, and Mn. The BC550 reduced the amount of dissolved Pb and showed a different pattern of Eh-pH in the soil slurry compared with BM and BC300. This might be attributed to its higher alkalinity and surface area. The highest amount of dissolved Pb was found at slightly anoxic conditions (−100 to 0 mV) in CS (control soil), S&BM (soil amended with BM), and S&BC300 (soil amended with BC300), which could be associated with the dissolution of Fe/Mn oxides. Moreover, the fitting results of Pb X-ray absorption fine structure (XAFS) indicated that the proportion of Pb(CH3COO)2 was decreasing when changing from anoxic to oxic condition in S&BC300, while the Pb speciation pattern in soil was stable in S&BC550. These results suggested that BC550 is more suitable amendment for Pb immobilization than BM and BC300 in this study. In addition, biochar produced at higher temperatures can be more stable so it can be suitable for remediation of Pb-contaminated soils which are frequently flooded.
AB - Biochar can reduce the mobility and availability of potentially toxic elements (PTEs) in soils and improve soil properties. However, immobilization efficiencies of biochar can be varied according to environmental conditions, such as pH and redox potential (Eh), especially for soils under flood-dry cycles. In the current study, biochar produced at 300 and 550 °C (referred as BC300 and BC550, respectively) and its feedstock (pine sawdust biomass, BM) were used to amend a lead (Pb)-contaminated soil under pre-defined redox windows (from −300 to +250 mV). Key features of the soil-solution were evaluated in detail, including pH, dissolved organic carbon, sulphate, and dissolved Al, Fe, and Mn. The BC550 reduced the amount of dissolved Pb and showed a different pattern of Eh-pH in the soil slurry compared with BM and BC300. This might be attributed to its higher alkalinity and surface area. The highest amount of dissolved Pb was found at slightly anoxic conditions (−100 to 0 mV) in CS (control soil), S&BM (soil amended with BM), and S&BC300 (soil amended with BC300), which could be associated with the dissolution of Fe/Mn oxides. Moreover, the fitting results of Pb X-ray absorption fine structure (XAFS) indicated that the proportion of Pb(CH3COO)2 was decreasing when changing from anoxic to oxic condition in S&BC300, while the Pb speciation pattern in soil was stable in S&BC550. These results suggested that BC550 is more suitable amendment for Pb immobilization than BM and BC300 in this study. In addition, biochar produced at higher temperatures can be more stable so it can be suitable for remediation of Pb-contaminated soils which are frequently flooded.
KW - Black carbon
KW - Immobilization/stabilization
KW - Lead dissolution/mobility
KW - Paddy soil
KW - XANES spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85076490584&partnerID=8YFLogxK
U2 - 10.1016/j.envint.2019.105376
DO - 10.1016/j.envint.2019.105376
M3 - Journal article
C2 - 31855801
AN - SCOPUS:85076490584
SN - 0160-4120
VL - 135
JO - Environment international
JF - Environment international
M1 - 105376
ER -