Kinetic analysis of catalytic hydrodechlorination process of polychlorinated biphenyls (PCBs)

Murena, Fabio

doi:10.1016/s0926-3373(00)00157-0

Cited by 64 publications

(30 citation statements)

References 15 publications

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“…These observations could be related to the positions of chlorine on the molecule; it was found that orto-chlorine is less reactive than those in the methaand para-positions (LaPierre et al, 1978). Similar results were also found by Murena and Schioppa (2000); they also found that the HDC depends on the nature of the atom adjacent to the chlorine atom, which is substituted. For example, the HDC rate is higher when the atoms adjacent to the substituted chlorine atom are both hydrogen, and the HDC depends on the position of the chlorine atom with respect to the phenyl bond.…”

Section: Discussionsupporting

confidence: 63%

“…It has been reported that the hydrodechlorination reaction of both the ClBzs and PCBs occurs consecutively, which means that the selectivity data are described through a stepwise process, where at each step, the removal of a chlorine atom takes place, (LaPierre et al, 1978;Murena and Schioppa, 2000). However, it has also been shown that other parameters could play a major role in the reactivity of HDC reactions.…”

Section: Discussionmentioning

confidence: 99%

“…Earlier studies were carried out by LaPierre et al (1978), who studied the kinetics and mechanism of the catalytic hydrodechlorination of a mixture of PCBs in a batch reactor using 61% of Ni on Kieselguhr catalysts at temperatures between 25 and 100 C and a H 2 pressure of 50 atm. Murena and Schioppa (2000) studied the kinetics of the hydrodechlorination of two tetrachlorobiphenyls (2,4,4 0 ,6 and 2,3,4,5) on a Ni-Mo=c-Al 2 O 3 catalyst at 250…”

Section: Introductionmentioning

confidence: 99%

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Total Hydrodechlorination of Industrial Transformer Oil on Metal-Supported Catalysts

Benitez

Angel

2009

Chemical Engineering Communications

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The hydrodechlorination (HDC) of transformer oil, which consists of a mixture of chlorinated benzene compounds (ClBzs) and polychlorinated biphenyls (PCBs), was carried out in liquid phase by using Pd=C, Ru=C, Rh=C, and Pd=Al 2 O 3 catalysts under mild reaction conditions: 25 C and hydrogen pressure of 2 bar. On the Pd=Al 2 O 3 catalysts, the total hydrodechlorination of the ClBzs and PCBs was reached after 50 h of reaction. Benzene and biphenyl aromatic compounds as well as total and partially hydrogenated products such as cyclohexane, bicyclohexane, and cyclohexylbenzene were obtained.

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Section: Discussionsupporting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Total Hydrodechlorination of Industrial Transformer Oil on Metal-Supported Catalysts

Benitez

Angel

2009

Chemical Engineering Communications

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“…The reason may be that the surface reactivity of materials was not only dependent on the surface area and pore volume, but also other properties such as phase composition [19]. Similar case about the lower reactivity held by The identification of the newly formed PCB products, as listed in Table S3, indicated the occurrence of a reductive hydrodechlorination reaction during the degradation of CB-209 on the iron-based spinels [36,37]. For the degradation of CB-209 over Fe 3 O 4 , the detected hydrodechlorinated products included nonachlorobiphenyl (NoCB), octachlorobiphenyl (OcCB), heptachlorobiphenyl (HpCB), hexachlorobiphenyl (HxCB), pentachlorobiphenyl (PeCB), tetrachlorobiphenyl (TeCB), trichlorobiphenyl (TrCB), and dichlorobiphenyl (DiCB).…”

Section: Activity Testmentioning

confidence: 86%

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Huang¹,

Su²,

Zhang³

et al. 2013

Journal of Hazardous Materials

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h i g h l i g h t s• The NiFe 2 O 4 had the highest activity in degradation of CB-209, followed by Fe 3 O 4 .• Hydroxyl species, organic acids, PCBs and chlorobenzenes were identified as products.• Three degradation reactions and one combination reaction competitively occurred.• Hydrodechlorination of CB-209 was more favored over Fe 3 O 4 than NiFe 2 O 4 .• Oxidation reaction of CB-209 was more favored over t r a c tA series of mesoporous iron-based spinel materials were synthesized to degrade polychlorinated biphenyls (PCBs), with CB-209 being used as a model compound. The materials were characterized by X-ray powder diffraction (XRD), pore structure analysis, and X-ray photoelectron spectroscopy (XPS). A comparison of the dechlorination efficiencies (DEs) of the materials revealed that NiFe 2 O 4 had the highest DE, followed by Fe 3 O 4 . Newly produced polychlorinated biphenyls, chlorinated benzenes, hydroxyl species and organic acids were detected by gas chromatography-mass spectrometry, high performance liquid chromatography-mass spectrometry and ion chromatograph. Identification of the intermediate products indicates that three degradation pathways, hydrodechlorination, the breakage of C C bridge bond and oxidative reaction, accompanied by one combination reaction, are competitively occurring over the iron-based spinels. The relative amounts of produced three NoCB isomers were illustrated by the C Cl BDEs of CB-209 at meta-, para-and ortho-positions, and their energy gap between HOMO and LUMO. The consumption of the reactive oxygen species caused by the transformation of Fe 3 O 4 into Fe 2 O 3 in the Fe 3 O 4 reaction system, and the existence of the highly reactive O 2 −• species in the NiFe 2 O 4 reaction system, could provide a reason why the oxidation reaction was more favored over NiFe 2 O 4 than Fe 3 O 4 .

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“…Dechlorination is an effective alternative procedure for decomposing chlorinated organic wastes under relatively mild conditions without the formation of the toxic by-products (12,13). Catalytic dechlorination with noble-metal and transition-metal catalysts is an especially simple and efficient method.…”

Section: Introductionmentioning

confidence: 99%

Enhanced dechlorination of chlorobenzene compounds on fly ash: effects of metals, solvents, and temperature

Ghaffar

Tabata

2010

Green Chemistry Letters and Reviews

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Dechlorination of di-chlorobenzene and tri-chlorobenzene on fly ash was optimized. Solutions of sulfur with alkaline solutions of potassium hydroxide, sodium hydroxide, and calcium hydroxide were applied for dechlorination of chlorobenzene compounds. Higher dechlorination (%) on surface of fly ash was achieved in sulfur and calcium hydroxide mixture, which further was enhanced with the addition of sodium hydroxide. Higher dechlorination (%) was obtained at 908C, where metals in general, and copper and lead, in particular, enhance the catalytic potential of fly ash for dechlorination by hydrodechlorination and substitution reactions. But at high temperatures (120Á1708C), dechlorination process was adversely affected by these metals. Moreover, the fly ash particles provided the surface to accomplish reduction and substitution reactions by adsorbing the chlorinated aromatic compound, hydrogen, hydroxyl, and thiol ions. The effects of water, organic solvents, and temperature were studied and reactions conditions were optimized to get maximum dechlorination.

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Kinetic analysis of catalytic hydrodechlorination process of polychlorinated biphenyls (PCBs)

Cited by 64 publications

References 15 publications

Total Hydrodechlorination of Industrial Transformer Oil on Metal-Supported Catalysts

Total Hydrodechlorination of Industrial Transformer Oil on Metal-Supported Catalysts

Degradation of polychlorinated biphenyls using mesoporous iron-based spinels

Enhanced dechlorination of chlorobenzene compounds on fly ash: effects of metals, solvents, and temperature

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