Biochar Derived from Urban Green Waste Can Enhance the Removal of Cd from Water and Reduce Soil Cd Bioavailability

Xiang Li; Paramsothy Jeyakumar; Nanthi Bolan; Lianxi Huang; Muhammad Saqib Rashid; Zhongzhen Liu; Lan Wei; Hailong Wang

doi:10.3390/toxics12010008

Biochar Derived from Urban Green Waste Can Enhance the Removal of Cd from Water and Reduce Soil Cd Bioavailability

Toxics. 2023 Dec 21;12(1):8. doi: 10.3390/toxics12010008.

Authors

Xiang Li¹, Paramsothy Jeyakumar², Nanthi Bolan^{3

4}, Lianxi Huang¹, Muhammad Saqib Rashid¹, Zhongzhen Liu¹, Lan Wei¹, Hailong Wang^{5

6}

Affiliations

¹ Key Laboratory of Plant Nutrition, and Fertilizer in South Region, Ministry of Agriculture, Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation, Institute of Agricultural Resources and Environment, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
² Environmental Sciences, School of Agriculture & Environment, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
³ UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia.
⁴ The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6009, Australia.
⁵ School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, China.
⁶ Guangdong Provincial Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.

Abstract

The beneficial utilization of potentially increasing urban green waste (UGW) is critical for sustainable urban development in China. In this study, UGW was pyrolyzed at different temperatures, and the resulting biochar was used to amend Cd-contaminated soils to grow cabbage. Our results showed that the Cd adsorption capacity of UGW-biochar was positively correlated with the surface area, O/C, and (O+N)/C value of biochar. Furthermore, UGW-biochar was incorporated into three Cd-contaminated soils, including one acidic soil and two neutral soils, to assess its impact on the availability of Cd. The most substantial reduction in the concentration of available Cd was observed in the acidic soil, of the three tested soils. In the neutral soils, a more substantial reduction was found in the heavily Cd-contaminated soil compared to the lightly Cd-contaminated soil. UGW-biochar amendments to the three Cd-contaminated soils resulted in an increase in the cabbage biomass in acidic soil, whereas in neutral soils, it increased in lightly contaminated soils but decreased in heavily contaminated soils. Additionally, the Cd bioaccumulation factor (BCF), translocation factor (TF), and removal efficiency (RE), as impacted by the biochar application, were calculated in the lightly Cd-contaminated soil-cabbage system. The BCF decreased from 5.84 to 3.80 as the dosage of the UGW-biochar increased from 0% to 3%, indicating that the UGW-biochar immobilized Cd and reduced its bioaccumulation in cabbage roots. Based on our investigations, UGW-biochar effectively immobilizes Cd by reducing its mobility and bioavailability in a lightly contaminated environment matrix.

Keywords: Cd; adsorption; biochar immobilization; soil remediation; urban green waste.

Grants and funding

The open competition program of the top ten critical priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province, Grant No: (2022SDZG08); the Guangxi Key Natural Science Foundation (Guangdong-Guangxi Joint Fund Project) (2022GXNSFDA080008); the Science and Technology Planning Project of Guangdong Province, China (2019B121201003, 2021B1212050020); the Low carbon agriculture and carbon neutralization Research Center, GDAAS (XT202220); Guangdong Foundation for Program of Science and Technology Research, China (2023B1212060044).