| 1,2,4,5-四氯苯在沉积物中的解吸动力学 |
| 摘要点击 4665 全文点击 2442 投稿时间：2008-03-29 修订日期：2008-06-05 |
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| 中文关键词 沉积物 1,2,4,5-四氯苯 解吸 动力学 |
| 英文关键词 sediment 1,2,4,5-tetrachlorobenzene desorption kinetics |
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| 中文摘要 |
| 采用批量实验，研究了沉积物有机质特性、溶质负载量和温度对1,2,4,5-四氯苯在沉积物上解吸动力学的影响.用4参数2室一级动力学模型描述了1,2,4,5-四氯苯在沉积物上的解吸过程.结果表明，在本研究中的每个解吸体系，1,2,4,5-四氯苯慢解吸速率常数ks要比快解吸速率常数kr低2个数量级以上，说明慢解吸是整个解吸过程中的速控步骤；1,2,4,5-四氯苯在不同沉积物上的ks范围为1.19×10-3～2.88×10-3 h-1，解吸过程显著受沉积物NOM特性的影响，沉积物NOM的聚合度越高，1,2,4,5-四氯苯的解吸速度和程度越低；随着在沉积物中的初始负载量由13.3 μg·g-1增加至25.3 μg·g-1，1,2,4,5-四氯苯的ks由1.26×10-3 h-1增加至2.52×10-3 h-1；1,2,4,5-四氯苯在沉积物上的解吸速度随着温度的升高而显著加快，慢解吸活化能Ea在9.45～21.43 kJ·mol-1之间，这为沉积物中污染物生物降解的可行性提供了科学依据. |
| 英文摘要 |
| Sediment desorption batch technique experiments were conducted to study the influence of different types of natural organic matter(NOM) of sediment, initial solid-phase solute loading levels and temperatures on the desorption rates of 1,2,4,5-tetrachlorobenzene. A 4-parameter biphasic first-order kinetic model described the desorption of 1,2,4,5-tetrachlorobenzene from the sediments. The results indicate that the rate constants ks for the slowly desorbing fraction of each sample is up to 2 orders of magnitude lower than the corresponding rate constants kr for the rapidly desorbing fraction, suggesting that the slow desorption is the rate-limiting step. Desorption rate constants for the slowly desorbing fraction are found to range from 1.19×10-3 h-1 to 2.88×10-3 h-1 for sediments that contain different types of NOM, respectively; rates and extents of 1,2,4,5-tetrachlorobenzene on several sediments increases with lower degree of sediment NOM condensation. When the sorbed initial solid-phase 1,2,4,5-tetrachlorobenzene concentration increases from 13.3 μg·g-1 to 25.3 μg·g-1, the constant ks increases from 1.26×10-3 h-1 to 2.52×10-3 h-1. Moreover, the rate constants for desorption increase strongly with increasing temperature, and the activation enthalpies for slow desorption appears to be 9.45-21.43 kJ·mol-1, which can provide information on the feasibility of bioremediation of aged contaminants. |
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