| 阳离子类型对土霉素在2种土壤中吸附-解吸影响 |
| 摘要点击 2944 全文点击 1515 投稿时间：2008-03-02 修订日期：2008-04-02 |
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| 中文关键词 土霉素 吸附 解吸 阳离子 土壤污染 |
| 英文关键词 oxytetracycline(OTC) adsorption desorption cation soil contamination |
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| 中文摘要 |
| 以OECD Guideline 106为基础，采用批量平衡方法研究不同阳离子Ca2+、K+、Na+对土霉素在2种土壤(褐土和红壤)中的吸附-解吸影响.结果表明，不同阳离子条件下，土霉素的吸附-解吸不同程度地偏离线性模型，其中Freundlich模型可以对吸附和解吸数据进行良好的非线性拟合，平均拟合相关系数为0.989;除了KCl介质中土霉素在褐土中的吸附等温线呈线性外，其它介质条件下的等温吸附线均属“L”型等温吸附线.在同一阳离子介质中，土霉素在红壤(2.907～3.173)中的吸附容量(lgKf)始终高于褐土(2.577～2.885)，而在红壤(0.672～0.825)中吸附强度(1/n)始终低于褐土(0.713～1.005)，且在2种土壤中的吸附均以物理吸附为主.3种阳离子对土霉素在2种土壤中的吸附行为的影响存在较大的差异，同一土壤中阳离子类型对土霉素的吸附容量无显著影响;而与K+和Na+相比，Ca2+的存在显著降低溶液中土霉素在土壤上的吸附强度(p<0.05).土霉素在土壤上的解吸过程存在明显的滞后现象，平均滞后系数HI在0.015～0.053之间.在同一阳离子介质条件下，土霉素在褐土中的滞后系数显著高于红壤(p<0.05);在同一土壤中，不同阳离子对滞后系数的影响不同，其中在褐土中K+与Ca2+、Na+之间的差异达到极显著差异(p<0.01)，而3种阳离子对土霉素在红壤中的解吸滞后影响并无显著差异. |
| 英文摘要 |
| On the basis of the OECD Guideline 106，batch sorption methods were employed to reveal the effect of different cations (0.01 mol·L-1 Ca2+，K+ and Na+) on oxytetracycline (OTC) adsorption and desorption process in two tested soils (cinnamon soil and red soil).Results show that the Freundlich model is the best isotherm to describe the experimental data of adsorption and desorption，and the average fitting correlation coefficient is 0.989.Except for the adsorption isotherm of cinnamon soil on OTC in 0.01 mol·L-1 KCl，the other isotherms resemble the L-type curves.To the same cation，OTC adsorption capacity (lgKf) in the red soil (ranging from 2.907 to 3.173) is always higher than in the cinnamon soil (ranging from 2.577 to 2.885)，and the adsorption strength (1/n) in the red soil (ranging from 0.672 to 0.825) is always lower than the cinnamon (ranging from 0.713 to 1.005).The dominant mechanism is physical adsorption in two soils.To the same soil，cation species dont affect OTC adsorption capacity (lgKf) (p>0.05).And Ca2+ can reduce significantly the adsorption strength(p<0.05)，comparing with K+ and Na+.The apparent adsorption-desorption hysteresis is found，and the average hysteresis index (HI) in all soils are from 0.015 to 0.053.To the same cation，OTC HI is significantly higher than that of red soil (p<0.05).In cinnamon soil，there is significantly HI difference (p<0.01) between K+ and Ca2+，Na+.However，three cations have no significantly difference effect on HI in red soil. |
