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| Adsorption of nitrate nitrogen by peanut shell biochar |
| Received:February 26, 2016 |
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| KeyWord:biochar;nitrate nitrogen;adsorption kinetics;adsorption isotherm |
| Author Name | Affiliation | E-mail | | WANG Rong-rong | College of Life Science, Shanxi Agricultural University, Taigu 030800, China
Agro-Environmental Protection Institute, Ministry of Agriculture/Tianjin Engineering Research Center of Agricultural Ecological & Environmental Remediation, Tianjin 300191, China | | | LAI Xin | Agro-Environmental Protection Institute, Ministry of Agriculture/Tianjin Engineering Research Center of Agricultural Ecological & Environmental Remediation, Tianjin 300191, China | | | LI Jie | Agro-Environmental Protection Institute, Ministry of Agriculture/Tianjin Engineering Research Center of Agricultural Ecological & Environmental Remediation, Tianjin 300191, China | | | CHANG Hong | College of Life Science, Shanxi Agricultural University, Taigu 030800, China | 941004578@qq.com | | ZHANG Gui-long | Agro-Environmental Protection Institute, Ministry of Agriculture/Tianjin Engineering Research Center of Agricultural Ecological & Environmental Remediation, Tianjin 300191, China | zgl-2008@126.com |
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| Abstract: |
| Peanut shell was used to prepare biochar through low-oxygen pyrolysis(300℃). FTIR and XPS results of the biochar before and after batch equilibrium adsorption test showed that adsorption of NO3--N on the biochar was significantly affected by pH. The NO3--N adsorption quantity by biochar increased gradually with initial concentrations of NO3--N. At the initial concentration of 800 mg·L-1, the maximum adsorption capacity was 40 mg·g-1. Freundlich equation could be well fitted(R2=0.975) to the NO3--N isothermal adsorption. Adsorption of NO3--N by biochar was non-uniform multilayer process and could reach the equilibrium in 30 min. Pseudo secondary dynamic equation could effectively describe the adsorption kinetics, indicating that the adsorption was mainly chemical adsorption. FTIR and XPS results also suggested that the functional groups such as hydroxyl(-OH), aromatic ring carbonyl(-C=O), and aliphatic ether(-o-), which distributed on the surface of biochar, were involved in the adsorption process, and that the binding energy of C atoms connected to those functional groups increased. Considering the distribution of metal ions on the biochar surface, it is concluded that formation of hydrogen bond and metallic bond would be the main chemical mechanism of NO3--N adsorption by biochar. |
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