Catalytic Reduction of Chlorobenzenes with Pd/Fe Nanoparticles: Reactive Sites, Catalyst Stability, Particle Aging, and Regeneration
详细信息 查看全文
- 作者：Bao-Wei Zhu ; Teik-Thye Lim
- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：November 1, 2007
- 年：2007
- 卷：41
- 期：21
- 页码：7523 - 7529
- 全文大小：181K
- 年卷期：v.41,no.21(November 1, 2007)
- ISSN：1520-5851
文摘
Monochlorobenzene (MCB), dichlorobenzenes (DCBs), and1,2,4-trichlorobenzene (124TCB) dechlorination experimentsin water were carried out with freshly synthesized Pd/Feparticles. The pre- and postreacted Pd/Fe sampleswere characterized by applying various analytical techniques(XRD, SEM, TEM, and XPS). Chlorinated benzenes couldbe completely reduced by the Pd/Fe to benzene and thereaction followed the pseudo-first-order kinetics. The reactionrates followed the order TCB < DCBs < MCB, whileamong the DCBs the order was 1,4-dichlorobenzene >1,3-dichlorobenzene 1,2-dichlorobenzene. Insignificantreactions were observed with the unpalladized iron,suggesting that Pd was the only reactive site in the Pd/Feparticles. The aged Pd/Fe particles exhibited significantdecrease in its dechlorination reactivity. The loss of Pd/Fereactivity could be due to Pd dislodgment from the aged Pd/Fe particles and Pd islets encapsulation by the iron oxidesfilm developed over aging period. Reactivity of the aged Pd/Fe could be only partially restored after HCl treatment,while regeneration with the NaBH4 reduction method couldnot restore its activity, although zerovalent state of theiron was reinstated.