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| Adsorption of Pb(Ⅱ) by biochars derived from three types of biomass |
| Received:November 11, 2015 |
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| KeyWord:crop straw;lychee branches;biochar;Pb(Ⅱ);adsorption |
| Author Name | Affiliation | E-mail | | LIN Ning | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | | ZHANG Han | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | | JIA Zhen-zhen | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | | HUANG Ren-long | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | | | SHU Yue-hong | School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China | hongershu@163.com |
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| Abstract: |
| Three different raw materials, including rice straw, wheat straw, and lychee branches, were used to produce biochars by pyrolysis at 300, 400, 500, and 600 ℃. The characteristics of the biochars obtained were analyzed. The effects of biochar pyrolysis temperature and mineral composition and initial solution pH on Pb(Ⅱ) adsorption by biochars were examined. Results showed that pyrolysis temperature exhibited no obvious influence on Pb(Ⅱ) adsorption by rice and wheat straw derived biochars, while the adsorption of Pb(Ⅱ) by lychee derived biochar increased with increasing pyrolysis temperature. As solution pH increased from 3.0 to 6.0, the amount of Pb(Ⅱ) adsorbed on all biochars gradually increased. Adsorption isotherms of Pb(Ⅱ) by these biochars fit the Freundlich model well. In addition, lychee-derived biochar showed greater Pb(Ⅱ) adsorption than the biochars derived from rice and wheat straws. Chemical precipitation of Pb(Ⅱ) with mineral components might be the main mechanism of Pb(Ⅱ) adsorption by these biochars. Lychee-derived biochar contained a variety of functional groups, such as -OH, -COOH, and C=C, thus providing different adsorption sites, including aromatic-π structures(for cation-π interaction) and oxygen-containing groups(for ion exchange adsorption) for Pb(Ⅱ) adsorption. |
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