Fe2O3微纳米材料对八氯萘的热催化降解及其机制研究
Catalytic thermal degradation of octachloronaphthalene over Fe2O3 micro/nanomaterial and its explored mechanism
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摘要: 本文研究了制备的α-Fe2O3微/纳米材料对八氯萘(octachloronaphthalene,CN-75)的催化降解活性及降解机制.在300 ℃下动力学研究发现,α-Fe2O3降解CN-75的反应行为呈现准一级动力学反应特征,反应速率常数为0.075 min-1.在α-Fe2O3催化下CN-75能够发生逐级加氢脱氯反应,生成一系列的七氯至二氯萘产物,且初始加氢脱氯优先发生在α位.此外,CN-75还能发生氧化开环反应生成甲酸、乙酸等中间产物.根据检测到的降解产物推测CN-75在α-Fe2O3上的降解反应历程为:CN-75→CN-73→CN-66/67→CN-54、CN-52、CN-51、CN-50→……→HCOOH+CH3COOH.Abstract: Degradation of octachloronaphthalene(CN-75) was performed over as-prepared α-Fe2O3 micro/nano materials. The degradation process conforms to the first order reaction kinetics with kobs=0.075 min-1 at 300 ℃.The identification of heptachloronaphthalene to dichloronaphthalene as the products indicates the occurrence of successive hydrodechlorination reactions during the degradation of CN-75 over the prepared α-Fe2O3. The Cl atom at α-position was removed preferentially the β-position. Furthermore, the oxidative products, such as formic and acetic acids, were identified simultaneously, suggesting that CN-75 can be ring-cracked into small organic molecules. According to the identified products,the pathway for the degradation of CN-75 over α-Fe2O3 was speculated as the following:CN-75→CN-73→CN-66/67→CN-54、CN-52、CN-51、CN-50→……→HCOOH+CH3COOH.
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Key words:
- octachloronaphthalene /
- α-Fe2O3 /
- Fe3O4 /
- successive hydrodechlorination
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