| 自组装哑铃状Fe3O4微/纳米材料对十溴联苯的热催化降解 |
| 摘要点击 2326 全文点击 1474 投稿时间：2015-07-29 修订日期：2015-09-30 |
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| 中文关键词 自组装哑铃状Fe3O4 微/纳米材料 热催化降解 十溴联苯 加氢脱溴 |
| 英文关键词 self-assembled dumbbell-like iron oxides micro/nanomaterial thermocatalytic degradation BB209 hydrodebromination |
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| 中文摘要 |
| 多溴联苯(PBBs)是一类新型持久性有机污染物,具有高毒性和生物累积性,对人类健康和生态环境具有潜在危害. 为探究PBBs的消减技术和降解机制,利用多元醇介导自组装法制备出了哑铃状形貌的Fe3O4前驱体,将前驱体在氮气氛围下焙烧制得哑铃状Fe3O4微/纳米材料,以十溴联苯(BB209)作为模型化合物进行热催化降解研究. 结果发现,哑铃状Fe3O4前驱体生长过程分为无定型粒子的快速成核和初级粒子间相互团聚结晶两个阶段; 哑铃状Fe3O4对BB209表现出较高的降解活性,在300℃下反应30 min时,Fe3O4对BB209的降解率几乎已达到100%; 在哑铃状Fe3O4降解BB209的产物中检测到一系列的从九溴代联苯到一溴代联苯产物与联苯产物,表明在降解过程中存在加氢脱溴反应路径; 在降解产物中鉴定出3种九溴联苯异构体BB206、 BB207、 BB208,且3种异构体含量的大小顺序为:BB207 > BB208 > BB206,表明不同取代位上Br的活性相对大小为:间位 > 对位 > 邻位. |
| 英文摘要 |
| Polybrominated biphenyls (PBBs) are a group of new persistent organic pollutants, which have high toxicity and long-term bioaccumulation, and cause potential risks to human beings and aquatic ecosystem. Self-assembled dumbbell-like Fe3O4 was synthesized via ethylene-glycol mediated method to degrade PBBs, using BB209 as a model compound. The results showed that the growth process of dumbbell-like Fe3O4 precursor had two stages involving a fast nucleation of amorphous primary particles followed by a slow aggregation and crystallization of primary particles. Dumbbell-like Fe3O4 showed high activity for degradation of BB209 at the reaction time of 30 min with the degradation efficiency of nearly 100% at 300℃. A whole series of nonabromobiphenyl to monobromobiphenyl and biphenyls were detected as the degradation products of BB209 by dumbbell-like Fe3O4, indicating the occurrence of successive hydrodebromination reaction. Furthermore, the amounts of three NoBB isomers followed the order of BB207 > BB208 > BB206, indicating that the reactivity of C—Br of BB209 was in order of meta- > para- > ortho-positions. |
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