Cyclodextrin Polymers as Highly Effective Adsorbents for Removal and Recovery of Polychlorobiphenyl (PCB) Contaminants in Insulating Oil

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• 作者：Shintaro Kawano ; Toshiyuki Kida ; Kazuhiro Miyawaki ; Yuki Noguchi ; Eiichi Kato ; Takeshi Nakano ; Mitsuru Akashi
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：July 15, 2014
• 年：2014
• 卷：48
• 期：14
• 页码：8094-8100
• 全文大小：337K
• ISSN：1520-5851

文摘

A total of 179 countries (parties) ratified the Stockholm Convention on persistent organic pollutants (POPs) and agreed to destroy polychlorobiphenyls (PCBs) and develop a sound management plan by 2028. Currently, still 3 million tons of PCB-contaminated oil and equipment need to be managed under the Stockholm Convention. Thus, the development of a facile and environmentally benign method to treat large amounts of oil stockpiles contaminated with PCBs is a crucial subject. Herein, we report that cyclodextrin (CD) polymers, which are easily prepared by cross-linking the renewable cyclic oligosaccharide 纬-cyclodextrin (纬-CD) with dibasic acid dichlorides, are a new selective and powerful adsorbent to remove PCB contaminants in oil. When PCB (100 ppm)-contaminated oil was passed through a column packed with the terephthaloyl-cross-linked 纬-CD polymer (TP-纬-CD polymer) at 80鈥?10 掳C, the PCB contaminants were completely removed from the oil. Additionally, methyl esterification of the free carboxylic groups of the TP-纬-CD polymer enabled the complete recovery of the PCBs adsorbed on the polymer (with >99.9% recovery efficiency) by simply washing with acetone. The methyl-esterified TP-纬-CD polymer could be recycled at least 10 times for PCB adsorption without any loss in the adsorption capability. These results revealed that the 纬-CD polymers can function as highly effective and powerful adsorbents for the removal and recovery of PCBs from PCB-contaminated oil and, thus, significantly contribute to the protection of the global environment.