| 微波加热硝酸氧化改性稻壳基生物质炭对Pb(Ⅱ)和亚甲基蓝的吸附作用 |
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| 引用本文： | 车晓冬,丁竹红,胡忻,陈逸珺.微波加热硝酸氧化改性稻壳基生物质炭对Pb(Ⅱ)和亚甲基蓝的吸附作用[J].农业环境科学学报,2016,35(9):1773-1780. |
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| 作者姓名： | 车晓冬 丁竹红 胡忻 陈逸珺 |
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| 作者单位： | 1. 南京工业大学市政工程系,南京,211816;2. 南京工业大学环境科学系,南京,211816;3. 南京大学现代分析中心,南京,210093 |
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| 基金项目： | 国家自然科学基金重大研究计划培育项目（91543129） |
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| 摘 要： | 通过研究四种改性生物质炭吸附重金属离子Pb(Ⅱ)和阳离子型染料亚甲基蓝的动力学效应、等温吸附效应、溶液初始pH效应和共吸附效应,探讨微波辅助加热在生物质炭氧化改性中的作用。结果表明,改性稻壳基生物质炭能够有效吸附Pb(Ⅱ)和亚甲基蓝,吸附容量显著高于初始生物质炭。Langmuir方程和Freundlich方程能很好地拟合改性稻壳基生物质炭吸附Pb(Ⅱ)和亚甲基蓝的等温数据(R20.90)。改性生物质炭吸附Pb(Ⅱ)和亚甲基蓝的动力学研究显示,改性稻壳基生物质炭对Pb(Ⅱ)和亚甲基蓝的吸附主要发生在前2 h内,吸附过程符合伪二级动力学模型。随着溶液中pH的增大,Pb(Ⅱ)的去除率迅速增加,并在pH6时达到最大,亚甲基蓝的去除率在实验pH范围内也随pH缓慢上升,在pH为8~9时达到最大并逐渐趋于平衡。Pb(Ⅱ)和亚甲基蓝的共吸附效应表明,随着摩尔比值MB/Pb(Ⅱ)]的增大,亚甲基蓝抑制了改性稻壳基生物质炭对Pb(Ⅱ)的吸附。微波加热硝酸氧化改性显著提高600℃热裂解生物质炭对Pb(Ⅱ)的吸附性能和300℃热裂解生物质炭对亚甲基蓝的吸附性能。
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| 关 键 词： | 生物质炭 等温吸附 动力学吸附 共吸附 |
| 收稿时间： | 3/5/2016 12:00:00 AM |
Sorption and co-sorption of methylene blue and Pb(Ⅱ)onto rice husk-based biochars modified by nitric acid via microwave heating |
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| CHE Xiao-dong,DING Zhu-hong,HU Xin and CHEN Yi-jun.Sorption and co-sorption of methylene blue and Pb(Ⅱ)onto rice husk-based biochars modified by nitric acid via microwave heating[J].Journal of Agro-Environment Science( J. Agro-Environ. Sci.),2016,35(9):1773-1780. |
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| Authors: | CHE Xiao-dong DING Zhu-hong HU Xin and CHEN Yi-jun |
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| Institution: | Department of Municipal Engineering, Nanjing Tech University, Nanjing 211816, China,Department of Environmental Science, Nanjing Tech University, Nanjing 211816, China,State Key Laboratory of Analytical Chemistry for Life Science, Center of Material Analysis, Nanjing University, Nanjing 210093, China and State Key Laboratory of Analytical Chemistry for Life Science, Center of Material Analysis, Nanjing University, Nanjing 210093, China |
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| Abstract: | Biochars derived from various biomass feedstocks through slow pyrolysis/carbonization in an oxygen limited environment have been considered as promising low-cost and sustainable sorbents for organic and inorganic contaminants' removal from aqueous solution. The related researches show that appropriate chemical modification of the pristine biochars will improve its adsorption capacity greatly. In this work, rice husk, a common agricultural by product, was chosen as a feedstock to prepare biochars through the pyrolysis at 600 ℃ and 300 ℃under oxygen-limited conditions. The resulting pristine biochars were oxidated by nitric acid via microwave heating and water-bath heating, respectively, to obtain four kinds of modified biochars. Then, the batch adsorption experiments of a cationic dye-methylene blue(MB)and a heavy metal ion-Pb(Ⅱ)onto the modified biochars were carried out to compare the adsorption effect of different biochars. The results in-dicated that the modified biochars exhibited greater adsorption capacity for Pb(Ⅱ)and MB than the pristine biochars, and the experimental data could be well fitted by the Langmuir and Freundlich isotherm model(R2﹥0.90). Kinetic data showed that the adsorption of Pb(Ⅱ) and MB onto the modified biochars followed well with the pseudo-second order kinetic model, and the adsorption reached equilibrium in about 2 h. In the pH range of 2~6, the removal of Pb(Ⅱ)increased with the increase of solution pH and reached the maximum at pH 6. The removal rates of MB also increased with pH increasing from 4 to 8, and the maximum value was observed at pH 8. The co-adsorption experi-mental results showed that the adsorption of Pb(Ⅱ)onto modified biochars was greatly decreased with increasing molar ratio of MB/Pb (Ⅱ), suggesting the possible competitive adsorption of MB and Pb(Ⅱ)onto biochars. Biochars modified with different heating methods had different adsorption performances for Pb(Ⅱ)and MB. |
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| Keywords: | biochar adsorption isotherm adsorption kinetics co-sorption |
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