Investigating the mechanisms of biochar's removal of lead from solution

Publication Type:
Journal Article
Citation:
Bioresource Technology, 2015, 177 pp. 308 - 317
Issue Date:
2015-02-01
Full metadata record
© 2014 Elsevier Ltd. The objective of this study was to investigate the relationship between Pb 2+ adsorption and physicochemical properties of biochars produced at different pyrolytic temperatures. Ten biochars were prepared from peanut shell (PS) and Chinese medicine material residue (MR) at 300-600°C. Adsorption kinetics and isotherms were determined, and the untreated and Pb 2+ -loaded biochars were analyzed by FTIR, SEM-EDX and XRD. Functional groups complexation, Pb 2+ -π interaction and precipitation with minerals jointly contributed to Pb 2+ adsorption on these biochars. New mineral precipitates (e.g., Pb 2 (SO 4 )O and Pb 4 (CO 3 ) 2 (SO 4 )(OH) 2 ) formed during Pb 2+ sorption. For high-temperature biochars (≥500°C), Pb 2+ sorption via complexation reduced, but the contribution of Pb 2+ -π interaction was enhanced. Dramatic reduction of Pb 2+ sorption on demineralized biochars indicated the dominant role of minerals. These results are useful for screening effective biochars as engineered sorbents to remove or immobilize Pb 2+ in polluted water and soil.
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