Sorption mechanisms of lead on silicon-rich biochar in aqueous solution: Spectroscopic investigation
Journal
Science of The Total Environment
Journal Volume
672
Date Issued
2019
Author(s)
Jianhong Li
Lirong Zheng
Shan-Li Wang
Zhipeng Wu
Weidong Wu
Nabeel Khan Niazi
Sabry M. Shaheen
Jorg Rinklebe
Nanthi Bolan
Yong Sik Ok
Hailong Wang
Abstract
© 2019 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(C 2 H 3 O 2 ) 2 ), Pb 3 (PO 4 ) 2 , PbSiO 3 , and PbCO 3 . On phytoliths in CFB500, Pb 2+ ions were mainly sorbed on the sites of silicate with a structure similar to PbSiO 3 . The contribution of binding sites for Pb 2+ 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 Pb 2+ . Our results suggest that CFB500 was a promising material for the remediation of Pb-contaminated aqueous environments (e.g., wastewater).
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(C 2 H 3 O 2 ) 2 ), Pb 3 (PO 4 ) 2 , PbSiO 3 , and PbCO 3 . On phytoliths in CFB500, Pb 2+ ions were mainly sorbed on the sites of silicate with a structure similar to PbSiO 3 . The contribution of binding sites for Pb 2+ 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 Pb 2+ . Our results suggest that CFB500 was a promising material for the remediation of Pb-contaminated aqueous environments (e.g., wastewater). © 2019
Subjects
Phytoliths skeleton | SEM-EDS | Sorption sites | Toxic metal(loid)s | XAFS | μ-XRF
Phytoliths skeleton; SEM-EDS; Sorption sites; Toxic metal(loid)s; XAFS; μ-XRF
SDGs
Other Subjects
Absorption spectroscopy; Binding sites; Carboxylation; Energy dispersive spectroscopy; Lead compounds; Musculoskeletal system; Organic carbon; Scanning electron microscopy; Silicates; Silicon; Sorption; X ray absorption; Phytoliths skeleton; SEM-EDS; Sorption sites; Toxic metals; XAFS; Boron compounds; biochar; calcium; carbonic acid; charcoal; copper; iron; lead; manganese; organic carbon; phosphate; potassium; silicate; silicon; unclassified drug; biochar; charcoal; lead; silicon; aqueous solution; biochar; lead; phytolith; remediation; scanning electron microscopy; silicon; sorption; spectral analysis; wastewater treatment; X-ray diffraction; aqueous solution; Article; binding site; chemical structure; controlled study; ecosystem restoration; energy dispersive X ray spectroscopy; microfluorometry; particle size; pollution; priority journal; scanning electron microscopy; sorption detoxification; spectroscopy; waste water; X ray absorption near edge structure spectroscopy; X ray diffraction; X ray fluorescence spectrometry; adsorption; chemistry; water pollutant; Adsorption; Charcoal; Lead; Silicon; Water Pollutants, Chemical
Publisher
Elsevier {BV}
Type
journal article