Extraction of PCBs and water from river sediment using liquefied dimethyl ether as an extractant
Extraction of PCBs and water from river sediment using liquefied dimethyl ether as an extractant
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DOI：
10.1016/j.chemosphere.2009.12.017
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发表时间：
2010-02-01
期刊：
影响因子：
8.8
通讯作者：
Morisawa, Shinsuke
中科院分区：
文献类型：
--
作者：
Oshita, Kazuyuki;Takaoka, Masaki;Morisawa, Shinsuke
研究了以液化二甲醚（DME）为萃取剂，采用溶剂萃取法同时去除河流沉积物中多氯联苯（PCBs）和水的可行性。二甲醚在常温常压下呈气态存在，能溶解有机物和一定量的水，因此，室温中压（0.6-0.8 MPa）液化二甲醚可有效地用于从污染沉积物中提取多氯联苯和水，并可从提取液中回收，易于重复利用。首先，我们评估了污染沉积物中多氯联苯和二甲醚的水提取特性。我们发现，使用液化二甲醚，提取时间为4320 s，液化二甲醚/沉积物比为60 mL g(-1)，同时从沉积物中提取了99%的多氯联苯和97%的水。多氯联苯和水的提取率用拟一级反应速率表示。其次，我们估计了提取后回收的二甲醚的数量。我们发现，DME的回收率为91-92%。换句话说，在提取和回收过程中，大约损失了5-10%的二甲醚。为了有效地回收二甲醚，有必要对该工艺进行优化。回收二甲醚的萃取效率与纯二甲醚相似。结果表明，液化二甲醚溶剂萃取法适用于从污染沉积物中提取多氯联苯和水。2009爱思唯尔有限公司版权所有。
We investigated whether polychlorinated biphenyls (PCBs) and water could be simultaneously removed from river sediment by solvent extraction using liquefied dimethyl ether (DME) as the extractant. DME exists in a gaseous state at normal temperature and pressure and can dissolve organic substances and some amount of water: therefore, liquefied DME under moderate pressure (0.6-0.8 MPa) at room temperature can be effectively used to extract PCBs and water from contaminated sediment, and it can be recovered from the extract and reused easily.First, we evaluated the PCB and water extraction characteristics of DME from contaminated sediment. We found that 99% of PCBs and 97% of water were simultaneously extracted from the sediment using liquefied DME at an extraction time of 4320 s and a liquefied DME/sediment ratio of 60 mL g(-1). The extraction rate of PCBs and water was expressed in terms of a pseudo-first-order reaction rate.Second, we estimated the amount of DME that was recovered after extraction. We found that 91-92% of DME could be recovered. In other words, approximately 5-10% of DME was lost during extraction and recovery. It is necessary to optimize this process in order to recover DME efficiently. The extraction efficiency of the recovered DME is similar to that of the pure DME.From the results, we conclude that solvent extraction using liquefied DME is suitable for extracting PCBs and water from contaminated sediment. (C) 2009 Elsevier Ltd. All rights reserved.