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| Adsorption of Aqueous Nitrate-N by Immobilized Modified Biochar |
| Received:August 25, 2014 |
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| KeyWord:biochar;modification;nitrate-N;adsorption;immobilization |
| Author Name | Affiliation | E-mail | | LI Li | State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China | | | CHEN Xu | State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China | | | WU Dan | State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China | | | WANG Ai-li | State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China | | | YANG Liu-yan | State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China | yangly@nju.edu.cn |
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| Abstract: |
| Adsorption characteristics of nitrate by two common biochars prepared from peanut shell and wheat straw were investigated. Laboratory adsorption experiments were conducted to assess the nitrate-N removal ability of two modified biochars from water at different time, pH, adsorbent dose, nitrate concentration and coexisting ion. To overcome the problem of biochar outflow, methods for immobilizing biochar were also explored. The results showed that nitrate adsorption was very fast within the first 6 hours and then reached equilibrium slowly in 24 hours. The adsorption increased with nitrate concentrations. The maximum adsorption amount was 2674 mg N·kg-1 and 1285 mg N·kg-1 for peanut shell and wheat straw biochars, respectively. The suitable pH for sorption ranged from 3 to 9. The optimal solid-liquid ratios were 10 g·L-1 and 28 g·L-1 for peanut shell and wheat straw biochars, respectively. At 2% alginate and 0.1 g·mL-1 biochar, the immobilized biochar microspheres were well-shaped and had a high adsorption capacity for nitrate. Immobilization did not significantly reduce the adsorption capacity of the modified biochars. Therefore, the immobilized modified biochars can be used as effective adsorbents to remove nitrate-N from water including sewage treatment plant effluents. |
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