| 不同温度下烧制的秸秆炭对可变电荷土壤吸附 Pb(Ⅱ)的影响 |
| 摘要点击 1614 全文点击 1234 投稿时间：2012-06-16 修订日期：2012-08-21 |
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| 中文关键词 制备温度 生物质炭 可变电荷土壤 Pb(Ⅱ) pH 吸附/解吸 |
| 英文关键词 pyrolysis temperature biochar variable charge soils Pb(Ⅱ) pH adsorption and desorption |
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| 中文摘要 |
| 研究了添加花生秸秆炭和稻草炭对2种可变电荷土壤的pH和吸附Pb(Ⅱ)的影响,结果表明,添加生物质炭使土壤pH提高了1.04~3.00个单位,且土壤pH增加幅度随生物质炭制备温度的升高而增加. 等温吸附实验的结果表明,添加生物质炭增加了Pb(Ⅱ)在可变电荷土壤表面的吸附量,当Pb(Ⅱ)初始浓度为2 mmol·L-1时,Pb(Ⅱ)的吸附量提高了12.6%~57.6%. 土壤对Pb(Ⅱ)的吸附量随体系pH升高而增加. Freundlich方程和Langmuir方程可以很好地拟合添加生物质炭后2种土壤对Pb(Ⅱ)的吸附等温线,且Freundlich方程拟合效果更好,r值均在0.94以上. 从Freundlich和Langmuir方程中表征吸附容量的k和Qm结果可以看出,花生秸秆炭促进Pb(Ⅱ)吸附的效果优于稻草炭,400℃下制备的生物质炭促进2种土壤吸附Pb(Ⅱ)的效果优于300℃和500℃下制备的生物质炭. 解吸实验结果表明,添加秸秆炭处理土壤表面吸附Pb(Ⅱ)的解吸量高于对照处理,但解吸量远低于吸附量,说明生物质促进土壤吸附Pb(Ⅱ)的机制涉及静电吸附和非静电吸附. |
| 英文摘要 |
| Effects of incorporation of the biochars generated from rice straw and peanut straw at different temperatures on soil pH and Pb(Ⅱ) adsorption were investigated with two variable charge soils. The soil pH increased by 1.04-3.00 units, and the increase in soil pH increased with the rise of pyrolysis temperature of the biochar. Results from adsorption isotherm experiments indicated that the incorporation of the biochar enhanced the adsorption of Pb(Ⅱ) by two soils. The adsorption of Pb(Ⅱ) was increased by 12.6%-57.6%, when the initial concentration of Pb(Ⅱ) is 2 mmol·L-1. The adsorption also increased with rising pH. Freundlich and Langmuir equations can be used to fit the adsorption isotherms of Pb(Ⅱ), but the Freundlich equation fitted the adsorption data better, the r-values are above 0.94. Soils incorporated with peanut straw char have a greater adsorption capacity for Pb(Ⅱ) than these incorporated with rice straw char as predicted by the parameters of k and Qm in Freundlich and Langmuir equations, respectively. The biochars generated at 400℃ have a greater enhancement on Pb(Ⅱ) adsorption by soils than 300℃ and 500℃. Desorption results showed that the desorption of Pb(Ⅱ) for the treatments with biochar added was greater than that for the control, but the amount of desorbed Pb(Ⅱ) was much lower than that of adsorbed Pb(Ⅱ). These results suggested that the enhanced adsorption of Pb(Ⅱ) by incorporation of the biochars involved at least two mechanisms: electrostatic adsorption and non-electrostatic adsorption. |
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