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| Effect of Fe-bearing Modifying Agents on Adsorption Performance of Magnetic Straw-Derived Biochars for Cr(Ⅵ) |
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Received:September 13, 2021
Revised:September 23, 2021
Accepted:September 27, 2021
Published Online:January 18, 2022
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| DOI：doi：10.3969/j.issn.1007-7545.2022.02.014 |
| KeyWord:hexavalent chromium; magnetic biochar; chemisorption; Fe-modification |
| Author | Institution |
| WU Wei-wei |
武汉科技大学 |
| MAO Lei |
武汉科技大学 |
| HU Hui-lan |
武汉科技大学 |
| GAN Wen-jun |
武汉科技大学 |
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| Abstract: |
| Wheat straw-derived biochar was modified by different iron modifiers (Fe3+, Fe2+, Fe2+/Fe3+, Fe0) to prepare four kinds of magnetic biochars for Cr(Ⅵ) adsorption. The characterization by specific surface area and pore size distribution, FTIR, XPS, XRD, and VSM, combined with the results from adsorption isotherm and adsorption kinetics shows that values of magnetization of Fe2+ and Fe3+-modified biochar is 11 A?m2/kg and 2.45 A?m2/kg respectively. Both Fe3+ and Fe2+ modification improve adsorption performance of biochar, while Fe0 weakens adsorption capacity of biochar. Fe2+/Fe3+-modified biochar exhibits good adsorption with specific surface area of 33.73 m2/g. Removal rate of Cr(Ⅵ) is 95.77% under the conditions including initial Cr(Ⅵ) concentration of 100 mg/L, biochar dosage of 0.2 g, pH value of 2, and temperature of 303 K. Adsorption of Cr(Ⅵ) on Fe2+/Fe3+-modified biochar conforms to quasi-second-order kinetic model and Langmuir adsorption isotherm model. Adsorption of Cr(Ⅵ) on biochar is monolayer chemisorption with uniform adsorption site energy. |
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