Effects of Zn in sludge-derived biochar on Cd immobilization and biological uptake by lettuce

Jia Gao; Tuokun Zhao; Daniel C W Tsang; Nan Zhao; Hang Wei; Mingyu Feng; Kunyuan Liu; Weihua Zhang; Rongliang Qiu

doi:10.1016/j.scitotenv.2020.136721

Effects of Zn in sludge-derived biochar on Cd immobilization and biological uptake by lettuce

Sci Total Environ. 2020 Apr 20:714:136721. doi: 10.1016/j.scitotenv.2020.136721. Epub 2020 Jan 15.

Authors

Jia Gao¹, Tuokun Zhao¹, Daniel C W Tsang², Nan Zhao³, Hang Wei¹, Mingyu Feng¹, Kunyuan Liu¹, Weihua Zhang⁴, Rongliang Qiu⁵

Affiliations

¹ School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
² Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
³ School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: zhaonan8@mail.sysu.edu.cn.
⁴ School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Guangzhou 510275, China; Shenzhen Research Institute, Sun Yat-sen University, Shenzhen 518057, China. Electronic address: zhangwh5@mail.sysu.edu.cn.
⁵ School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, Guangzhou 510275, China.

PMID: 31978776
DOI: 10.1016/j.scitotenv.2020.136721

Abstract

Considering the high Zn content of municipal sewage sludge and its competition with Cd during plant uptake due to their similar properties, the presence of Zn in sludge-derived biochar (SDBC) may affect Cd immobilization and uptake by plants. To confirm this, SDBC samples with different Zn contents were prepared and characterized. Their Cd immobilization behavior was studied by conducting batch sorption experiments, and their effects on Cd uptake by lettuce were explored by conducting hydroponic experiments. The results reveal that some Zn contained in the sewage sludge was transformed into ZnO during pyrolysis. The Brunauer-Emmett-Teller (BET) surface area of the SDBC samples containing 2324 mg kg^-¹ Zn (BC-2324) was 18.3 m² g^-1, which was 132% larger than that of the samples containing 1438 mg kg^-¹ Zn (BC-1438). The SDBC samples containing 1901 mg kg^-¹ (BC-1901) exhibited the highest Langmuir sorption capacity of 3476 mg kg^-¹, which is 115% higher than that of SB-1438. Furthermore, the lettuce remedied with SB-1901 exhibited 44% more biomass; lower peroxidase, catalase, and malondialdehyde activity; and 18.4% less Cd in the leaves of the lettuce than the lettuce remedied with BC-1438, suggesting the potential benefits of using Zn-rich SDBC for soil amendment.

Keywords: Cd uptake by lettuce; Farmland soil amendment; Metal immobilization; Potentially toxic elements; Sludge-derived biochar; Sustainable remediation.

MeSH terms

Cadmium
Charcoal
Lactuca
Sewage*
Soil
Soil Pollutants
Zinc

Substances

Sewage
Soil
Soil Pollutants
biochar
Cadmium
Charcoal
Zinc