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Removal of PCDDs/DFs and PCBs from contaminated sediment using liquefied dimethyl ether as an extractant.

使用液化二甲醚作为萃取剂去除受污染沉积物中的 PCDD/DF 和 PCB。

基本信息

批准号：
20360244
负责人：
TAKEDA Nobuo
金额：
$ 11.98万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

We investigated whether polychlorinated biphenyls (PCBs) and dioxins could be removed from river sediment by solvent extraction using liquefied dimethyl ether (DME) as the extractant. The efficiency of solvent extraction for the removal of organic contaminants and water is quite high. Moreover, it can be carried out under moderate pressure (0.6-0.8 MPa) at room temperature. The extractant can be recovered from the extract and reused in this process.Firstly, we compared extracting characteristics of the continuous processing with that of batch processing. We found that the latter showed quite low water extraction efficiency in comparison with the former although PCBs extraction showed high efficiency in both. Secondly, we estimated the amount of DME that was recovered after extraction. We found that 98.6～102.2% of DME could be recovered. The extraction efficiency of the recovered DME is similar to that of the pure DME.Thirdly, we investigated the optimum condition for reaching best PCBs decomposition rate in Fenton's reaction to treat extract. Under the condition of 120 min reaction time and the four times addition of Fe^<2+>:H_2O_2 reagent at the concentration of 30mM:1000mM, almost 100% of PCBs was discomposed.Finally, we carried out the LCCO_2 analysis of this process. It was evaluated 526.3kg-CO_2/mgTEQ(decomposed-DXNs) and we concluded that this process is more suitable than the other processes.

以液化二甲醚为萃取剂，研究了用溶剂萃取法去除河流沉积物中的多氯联苯和二恶英的可行性。溶剂萃取法去除有机污染物和水的效率相当高。此外，它还可以在常温下的中压(0.6-0.8兆帕)下进行。首先，比较了连续和间歇两种工艺的提取特性。我们发现，与前者相比，后者的水提取效率相当低，尽管多氯联苯的提取效率两者都很高。其次，我们估计了提取后回收的二甲醚的量。结果表明，二甲醚的回收率为98.6~102.2%。回收的二甲醚的萃取率与纯二甲醚相当。再次，考察了Fenton反应处理萃取物时，达到最佳多氯联苯分解率的最佳条件。在反应时间120min、Fe~(2+)：lt；2+、Gt~(2+)：H_2O_2四次加入浓度为30：1000 mm的条件下，几乎100%的多氯联苯被分解，并对该过程进行了LCCO_2分析。对526.3 kg-CO_2/mgTEQ(分解-DXNS)进行了评价，得出该工艺比其他工艺更合适的结论。