Sorption mechanisms of lead on silicon-rich biochar in aqueous solution: Spectroscopic investigation

Jianhong Li; Lirong Zheng; Shan-Li Wang; Zhipeng Wu; Weidong Wu; Nabeel Khan Niazi; Sabry M Shaheen; Jörg Rinklebe; Nanthi Bolan; Yong Sik Ok; Hailong Wang

doi:10.1016/j.scitotenv.2019.04.003

Sorption mechanisms of lead on silicon-rich biochar in aqueous solution: Spectroscopic investigation

Sci Total Environ. 2019 Jul 1:672:572-582. doi: 10.1016/j.scitotenv.2019.04.003. Epub 2019 Apr 2.

Authors

Jianhong Li¹, Lirong Zheng², Shan-Li Wang³, Zhipeng Wu¹, Weidong Wu⁴, Nabeel Khan Niazi⁵, Sabry M Shaheen⁶, Jörg Rinklebe⁷, Nanthi Bolan⁸, Yong Sik Ok⁹, Hailong Wang¹⁰

Affiliations

¹ Institute of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, Hainan, PR China.
² Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, PR China.
³ Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan, ROC.
⁴ Institute of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, Hainan, PR China. Electronic address: wdwu@hainu.edu.cn.
⁵ Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; School of Civil Engineering and Surveying, University of Southern Queensland, Toowoomba 4350, Queensland, Australia.
⁶ 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, 21589 Jeddah, Saudi Arabia; University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, 33516 Kafr El-Sheikh, Egypt.
⁷ 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, 98 Gunja-Dong, Guangjin-Gu, Seoul, South Korea.
⁸ Global Center for Environmental Remediation, University of Newcastle, University Drive, Callaghan 2308, NSW, Australia.
⁹ Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
¹⁰ Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A & F University, Hangzhou 311300, PR China; School of Environmental and Chemical Engineering, Foshan University, Foshan 528000, PR China. Electronic address: hailong.wang@fosu.edu.cn.

PMID: 30965268
DOI: 10.1016/j.scitotenv.2019.04.003

Abstract

Unraveling sorption mechanisms of lead (Pb) to silicon (Si)-rich biochar at molecular scale in aqueous solution are essential for the effective application of the biochars to the remediation of Pb and other metal(loid)s pollution in the environment. Thus, this study investigated the contributions of phytoliths and other compounds to the Pb sorption on Si-rich coconut fiber biochar (CFB500) and the corresponding sorption mechanisms using spectroscopic techniques, including the micro-X-ray fluorescence (μ-XRF), X-ray absorption fine structure (XAFS), scanning electron microscopy combined with energy dispersive X-ray spectroscopy, and X-ray diffraction. The μ-XRF and XAFS results showed that K, Ca, Cu, Mn, and Fe were released and significantly related to Pb in Pb-loaded CFB500; four major Pb species were formed with similar structures to lead carboxylate (e.g., Pb(C₂H₃O₂)₂), Pb₃(PO₄)₂, PbSiO₃, and PbCO₃. On phytoliths in CFB500, Pb²⁺ ions were mainly sorbed on the sites of silicate with a structure similar to PbSiO₃. The contribution of binding sites for Pb²⁺ sorption was ascribed to the outer-wall of carbon skeleton of CFB500, which was stronger than that provided by the mineral oxide aggregate and phytoliths on CFB500. Organic carbon functional groups, inorganic carbonates, silicates and phosphates on CFB500 mostly dominated the sorption sites for Pb²⁺. Our results suggest that CFB500 was a promising material for the remediation of Pb-contaminated aqueous environments (e.g., wastewater).

Keywords: Phytoliths skeleton; SEM-EDS; Sorption sites; Toxic metal(loid)s; XAFS; μ-XRF.

MeSH terms

Adsorption
Charcoal / chemistry*
Lead / chemistry*
Silicon / chemistry
Water Pollutants, Chemical / chemistry*

Substances

Water Pollutants, Chemical
biochar
Charcoal
Lead
Silicon