Immobilization of cadmium and lead using phosphorus-rich animal-derived and iron-modified plant-derived biochars under dynamic redox conditions in a paddy soil

Xing Yang; He Pan; Sabry M Shaheen; Hailong Wang; Jörg Rinklebe

doi:10.1016/j.envint.2021.106628

Immobilization of cadmium and lead using phosphorus-rich animal-derived and iron-modified plant-derived biochars under dynamic redox conditions in a paddy soil

Environ Int. 2021 Nov:156:106628. doi: 10.1016/j.envint.2021.106628. Epub 2021 May 12.

Authors

Xing Yang¹, He Pan², Sabry M Shaheen³, Hailong Wang⁴, Jörg Rinklebe⁵

Affiliations

¹ Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong 528000, China; University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany.
² Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China.
³ University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; King Abdulaziz University, Faculty of Meteorology, Environment, and Arid Land Agriculture, Department of Arid Land Agriculture, Jeddah 21589, Saudi Arabia; University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, 33 516 Kafr El-Sheikh, Egypt.
⁴ Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong 528000, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China. Electronic address: hailong.wang@fosu.edu.cn.
⁵ University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; University of Sejong, Department of Environment, Energy and Geoinformatics, Guangjin-Gu, Seoul 05006, Republic of Korea. Electronic address: rinklebe@uni-wuppertal.de.

PMID: 33991874
DOI: 10.1016/j.envint.2021.106628

Abstract

Functionalized biochar has gained extensive interests as a sustainable amendment for an effective remediation of paddy soils contaminated with heavy metals (HMs). We examined the efficiency of pig carcass-derived biochar (P-rich biochar, total P = 8.3%) and pristine (raw biochar, total Fe = 0.76%) and Fe-modified (Fe-rich biochar, total Fe = 5.5%) green waste-derived biochars for the immobilization of cadmium (Cd) and lead (Pb) in a paddy soil under pre-defined redox conditions (Eh, from -400 to +300 mV). Average concentrations (μg L^-1) of dissolved Cd increased under reducing conditions up to 10.9 in the control soil, and decreased under oxidizing conditions to below the detection limit (LDL = 2.7) in the raw and Fe-rich biochar treated soils. Application of the raw biochar decreased the concentrations of dissolved Cd by 43-59% under Eh ≤ -100 mV, compared to the non-treated control, which was more effective than the Fe-rich biochar (31-59%) and the P-rich biochar (8-19%). The immobilization of Cd under low Eh might be due to its precipitation with sulfide (S^2-), whereas its immobilization under high Eh might be due to the associated increase of pH. Concentrations (μg L^-1) of Pb ranged from 29.4 to 198.2 under reducing conditions, and decreased to LDL (12.5) under oxidizing conditions. The P-rich biochar was more effective in immobilizing Pb than the raw and Fe-rich biochars, particularly under Eh ≤ 0 mV (55-82%), which might be due to the retention of Pb by phosphates. The raw and Fe-rich biochars immobilized Pb under low Eh (≤ -300 mV), but both biochars, particularly the Fe-rich biochar mobilized Pb under Eh higher than -200 mV, especially at +100 mV, due to the decrease of pH at this point (pH = 6.0 to 6.5). These results improved our understanding of using P-rich and Fe-rich functionalized biochars for the immobilization of Cd and Pb in a paddy soil under stepwise redox changes. The amendment of P-rich pig carcass-derived biochar to paddy soils could be a promising approach for mitigating the risk of Pb for human health and the environment. The raw and Fe-rich green waste-derived biochars can be used for immobilizing Cd and mitigating its risk in paddy soils under both reducing and oxidizing conditions.

Keywords: Feedstock; Gentle remediation; Heavy metal; Modified biochar; Paddy soil; Redox change.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cadmium
Charcoal
Iron
Lead
Oxidation-Reduction
Phosphorus
Soil Pollutants* / analysis
Soil*
Swine

Substances

Soil
Soil Pollutants
biochar
Cadmium
Charcoal
Phosphorus
Lead
Iron