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| Stabilization remediation of soil polluted by heavy metals using biochar prepared by co-pyrolysis with sludge and attapulgite |
| Received:November 09, 2021 Revised:February 09, 2022 |
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| KeyWord:sludge;attapulgite;biochar;stabilization;heavy metal |
| Author Name | Affiliation | E-mail | | TAO Ling | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Institute of Environmental Ecology, Lanzhou 730070, China
Gansu Hanxing Environmental Protection Co., Ltd., Lanzhou 730070, China | | | MA Ben | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Institute of Environmental Ecology, Lanzhou 730070, China | | | LI Zhongxing | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Institute of Environmental Ecology, Lanzhou 730070, China | | | ZHOU Yilei | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Institute of Environmental Ecology, Lanzhou 730070, China | | | REN Jun | Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, China
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Institute of Environmental Ecology, Lanzhou 730070, China
Gansu Hanxing Environmental Protection Co., Ltd., Lanzhou 730070, China
Gansu Haoyu Environment Protection Co., Ltd., Tianshui 741020, China | renjun@mail.lzjtu.cn |
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| Abstract: |
| The stabilization effect of sludge and attapulgite co-pyrolytic biochar prepared by adding attapulgite with different mass ratios (0, 5%, 10%, 15%, 20%, 25%, 30%)on heavy metals in the polluted soil of mining area was studied by stabilization experiment. The results showed that the addition of sludge-attapulgite co-pyrolytic biochar to the soil contaminated by heavy metals in the mining area, the soil pH value gradually increased with the increase of attapulgite content in biochar, the soil electrical conductivity and cation exchange capacity increased as well as. After stabilization of heavy metal contaminated soil by heavy metals in the mining area with biochar prepared by co-pyrolysis with sludge and attapulgite, the contents of heavy metals extracted by TCLP of Cd, Cu, Ni, Zn and Cr all showed a decreasing trend. Except for the contents of heavy metals extracted by DTPA of Cu increased by 5.93%~24.97%, the contents of heavy metals extracted by DTPA of Cd, Ni, Zn and Cr also decreased. The stabilization efficiency of Cu, Cd, Ni, Zn and Cr extracted by DTPA and TCLP were 94.32% and 94.71%, 94.75% and 95.60%, 86.63% and 91.75%, 90.02% and 99.03%, 92.54% and 96.65%, respectively. The acid-soluble Cd, Cu, Ni, Zn and Cr were also converted to a more stable residue state, and the repair efficiency was 42.50%, 33.87%, 57.92%, 33.74%, 42.36%, respectively. The sum of the four forms of heavy metals was in good agreement with the total amount of heavy metals, and the percentage recovery of heavy metals was between 82% and 105%. According to the standard risk grade of soil control, after passivation treatment of heavy metal contaminated soil, Cd, Cu, Ni, Zn and Cr were all at a low risk level. The potential risk index of Cd, Cu, Ni and Zn decreased, although the potential risk index of Cr increased, but the pollution level of Cr under all treatments was mild pollution. The results indicated that the addition of attapulgite enhances the stabilization function of sludge biochar and provides a new method for the rational utilization of sludge. |
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