Sorption mechanisms of lead on soil-derived black carbon formed under varying cultivation systems

Qingjie Zhao; Jianhong Li; Binoy Sarkar; Weidong Wu; Boling Li; Ruichun Liu; Mohsin Nawaz; Muhammad Zia-Ur-Rehman; Hailong Wang; Zhipeng Wu

doi:10.1016/j.chemosphere.2020.128220

Sorption mechanisms of lead on soil-derived black carbon formed under varying cultivation systems

Chemosphere. 2020 Dec:261:128220. doi: 10.1016/j.chemosphere.2020.128220. Epub 2020 Sep 3.

Authors

Qingjie Zhao¹, Jianhong Li², Binoy Sarkar³, Weidong Wu¹, Boling Li¹, Ruichun Liu⁴, Mohsin Nawaz⁵, Muhammad Zia-Ur-Rehman⁶, Hailong Wang⁷, Zhipeng Wu⁸

Affiliations

¹ College of Tropical Crops, Hainan University, Haikou, 570228, China.
² Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, 528000, China.
³ Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom.
⁴ Flood Control and Drought Relief Office of Hangjin County, Ordos, 017400, China.
⁵ Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, 570228, China.
⁶ Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.
⁷ Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, 528000, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A&F University, Hangzhou, 311300, China. Electronic address: hailong.wang@fosu.edu.cn.
⁸ College of Tropical Crops, Hainan University, Haikou, 570228, China. Electronic address: peter@hainanu.edu.cn.

PMID: 33113653
DOI: 10.1016/j.chemosphere.2020.128220

Abstract

The knowledge about lead (Pb) sorption on soil-derived black carbons (SBCs) under different cultivation intensities of soils is limited. In this study, chemical and spectroscopic methods were applied to investigate the Pb sorption mechanisms on SBCs in soils from a forest land, a rubber plantation area, and a vegetable farm with none, less and highly intensive cultivation, respectively, that are located in the Hainan Island of China. Results showed that the specific surface area and cation exchange capacity of the SBCs from the less and highly intensive cultivation soils were 4.5- and 2.7-fold, and 1.3- and 1.8-fold higher compared to that of SBC from the no-cultivation soil, which subsequently enhanced the Pb sorption capacities of SBCs in iron exchange fraction. Ion exchange and hydrogen bonded Pb fractions together accounted for about 80% of total Pb sorbed on all SBCs at an externally added 1000 mg L^-1 Pb solution concentration. The OC-O groups also played key roles in Pb sorption by forming complexes of OC-O-Pb-O and/or OC-O-Pb. Overall, SBCs in soils under all studied cultivation intensities showed high potential to sorb Pb (with the maximum absorbed Pb amount of 46.0-91.3 mg g^-1), and increased Pb sorption capacities of the studied soils by 18.7-21.1 mg kg^-1 in the stable fraction (complexation). Therefore, SBC might be a potential environment-friendly material to enhance the Pb immobilization capacity of soil.

Keywords: Aging of organic carbon; Biochar; Sequential desorption; TG/DTG; XPS.

MeSH terms

Adsorption
China
Environmental Pollutants / chemistry*
Environmental Pollutants / isolation & purification
Iron
Lead / chemistry*
Lead / isolation & purification
Soil / chemistry*
Soot / chemistry*

Substances

Environmental Pollutants
Soil
Soot
Lead
Iron