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| Adsorption of Hg(Ⅱ) by Biochars Produced from Sawdust and Rice Straw |
| Received:October 30, 2014 |
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| KeyWord:biochar;adsorption;Hg(Ⅱ);isotherm;kinetics |
| Author Name | Affiliation | E-mail | | ZHAO Ling-yu | School of Geography Science, Nanjing Normal University, Nanjing 210023, China | | | WANG Yan-hua | School of Geography Science, Nanjing Normal University, Nanjing 210023, China
Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China | wanyanhua@njnu.edu.cn | | YANG Hao | School of Geography Science, Nanjing Normal University, Nanjing 210023, China
Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China | | | WANG Hong | School of Geography Science, Nanjing Normal University, Nanjing 210023, China | | | XU Mei-na | School of Geography Science, Nanjing Normal University, Nanjing 210023, China | | | WANG Dan | School of Geography Science, Nanjing Normal University, Nanjing 210023, China | |
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| Abstract: |
| Biochar can greatly adsorb heavy metals from aqueous solution, thus significantly reducing their concentrations in water environment. In the present study, two biochars obtained from sawdust and rice straw at 600 ℃ were used to study their Hg(Ⅱ) adsorption from aqueous solution under different solution pH, sorbent rates, and contact time. The optimum pH value for Hg(Ⅱ) adsorption by biochars was approximately 5. Langmuir isotherm model fitted the isotherm data of Hg(Ⅱ) adsorption by both biochars, suggesting a functional group-limited sorption process. Kinetics of Hg(Ⅱ) adsorption by two biochars could be well described by the pseudosecond-order model. The intraparticle diffusion model illustrated that the adsorption of Hg(Ⅱ) by two biochars was controlled by internal diffusion and membrane diffusion. The scanning electron microscopy showed that the ion exchange was a major process for the Hg(Ⅱ) removal. Meanwhile, reduction and complexation reaction might also be responsible for the Hg(Ⅱ) adsorption. |
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