| 氯苯类化合物在沉积物上的非线性吸附行为 |
| 摘要点击 2345 全文点击 1138 投稿时间：2008-01-09 修订日期：2008-03-20 |
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| 中文关键词 氯苯类化合物（CBs） 沉积物 非线性 吸附 极性指数 |
| 英文关键词 chlorobenzenes（CBs） sediment nonlinear sorption polarity index |
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| 中文摘要 |
| 以5种自然沉积物为对象，采用批量平衡法，测定了氯苯、1,4-二氯苯、1,2,4-三氯苯和1,2,4,5-四氯苯在这5种沉积物样品上的吸附等温线，以研究沉积物自然有机质（NOM）的性质对氯苯类化合物（chlorobenzenes, CBs）吸附行为的影响.结果表明，1,2,4-三氯苯在虎门、黄沙、雅岗、三水、长洲5种沉积物中的等温吸附线性因子n都小于1，分别为0.956、 0.858、 0.872、 0.947和0.915，说明所有吸附等温线均为非线性；同时，非线性的程度n与极性指数（O+N）/C呈负相关关系，相关系数R2达0.994 7，表明NOM的聚合度（以极性指数为表征）直接影响着吸附非线性程度；5种沉积物对1,2,4-三氯苯的吸附亲和力（Koc）随沉积物极性指数的增大而减弱，说明NOM聚合度较高的沉积物对1,2,4-三氯苯的吸附亲和力更强；氯苯、1,4-二氯苯、1,2,4-三氯苯、1,2,4,5-四氯苯在同一种沉积物（黄沙）上吸附等温线的线性因子n分别0.755、 0.788、 0.858、 0.949，非线性程度按溶质分子由小到大的顺序依次减弱，说明溶质分子本身的性质也影响着CBs在沉积物上的吸附性能. |
| 英文摘要 |
| Sorption isotherms of chlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene and 1,2,4,5-tetrachlorobenzene on 5 sediments were examined to understand its sorption behavior. All systems examined exhibits nonlinear sorption. All sorption isotherms are nonlinear as evidenced by the Freundlich n values of 5 sediments being between 0.858 to 0.956. Sorption nonlinearity is found to be a function of the polarity index of sediments natural organic matter(NOM) with a high correlative coefficient of 0.994 7, suggesting that the degree of condensation of NOM, characterized by its polarity index, is correlated with the sorption behavior of 1,2,4-trichlorobenzene. In addition, the sorption affinity Koc) of the sediments for 1,2,4-trichlorobenzene increases with decreasing of NOM polar, indicating that a higher sorption affinity in the sediments is associated with a higher degree of condensation of NOM. The Freundlich n values of chlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene and 1,2,4,5-tetrachlorobenzene are 0.755, 0.788, 0.858, 0.949 respectively, indicating that the smaller CBs molecule may result in more significant sorption nonlinearity. |
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