Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts

Dichloromethane (DCM) is an important pollutant with very harmful effects on human health and the environment. Catalytic hydrodechlorination (HDC) is an environmentally friendly technology for its removal from gas streams; it avoids the formation of hazardous pollutants like dioxins and phosgene (pr...

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Main Authors: Sichen Liu, María Martin-Martinez, María Ariadna Álvarez-Montero, Alejandra Arevalo-Bastante, Juan José Rodriguez, Luisa María Gómez-Sainero
Format: Article
Language:English
Published: MDPI AG 2019-08-01
Series:Catalysts
Subjects:
Online Access:https://www.mdpi.com/2073-4344/9/9/733
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spelling doaj-dc9435cff27c43109544b2d3619fbaf72020-11-25T02:45:29ZengMDPI AGCatalysts2073-43442019-08-019973310.3390/catal9090733catal9090733Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C CatalystsSichen Liu0María Martin-Martinez1María Ariadna Álvarez-Montero2Alejandra Arevalo-Bastante3Juan José Rodriguez4Luisa María Gómez-Sainero5Departamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDepartamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDepartamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDepartamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDepartamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDepartamento de Ingeniería Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, SpainDichloromethane (DCM) is an important pollutant with very harmful effects on human health and the environment. Catalytic hydrodechlorination (HDC) is an environmentally friendly technology for its removal from gas streams; it avoids the formation of hazardous pollutants like dioxins and phosgene (produced by other techniques), and the products obtained can be reused in other industries. When compared to other precious metals, Pd/C catalyst exhibited a better catalytic activity. However, the catalyst showed a significant deactivation during the reaction. In this study, the oxidation state and particle size of Pd was monitored with time on stream in order to elucidate the transformations that the catalyst undergoes during HDC. The deactivation can be ascribed to the formation of a new PdC<i><sub>x</sub></i> phase during the first hour of reaction. Carbon atoms incorporated to Pd lattice come from (chloro)-hydrocarbons adsorbed in the metallic species, whose transformation is promoted by the HCl originating in the reaction. Nevertheless, the catalyst was regenerated by air flow treatment at 250 &#176;C, recovering the catalyst more than 80% of initial DCM conversion.https://www.mdpi.com/2073-4344/9/9/733palladiumactivated carbonhydrodechlorinationdeactivationregenerationpalladium carbide
collection DOAJ
language English
format Article
sources DOAJ
author Sichen Liu
María Martin-Martinez
María Ariadna Álvarez-Montero
Alejandra Arevalo-Bastante
Juan José Rodriguez
Luisa María Gómez-Sainero
spellingShingle Sichen Liu
María Martin-Martinez
María Ariadna Álvarez-Montero
Alejandra Arevalo-Bastante
Juan José Rodriguez
Luisa María Gómez-Sainero
Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
Catalysts
palladium
activated carbon
hydrodechlorination
deactivation
regeneration
palladium carbide
author_facet Sichen Liu
María Martin-Martinez
María Ariadna Álvarez-Montero
Alejandra Arevalo-Bastante
Juan José Rodriguez
Luisa María Gómez-Sainero
author_sort Sichen Liu
title Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
title_short Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
title_full Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
title_fullStr Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
title_full_unstemmed Recycling of Gas Phase Residual Dichloromethane by Hydrodechlorination: Regeneration of Deactivated Pd/C Catalysts
title_sort recycling of gas phase residual dichloromethane by hydrodechlorination: regeneration of deactivated pd/c catalysts
publisher MDPI AG
series Catalysts
issn 2073-4344
publishDate 2019-08-01
description Dichloromethane (DCM) is an important pollutant with very harmful effects on human health and the environment. Catalytic hydrodechlorination (HDC) is an environmentally friendly technology for its removal from gas streams; it avoids the formation of hazardous pollutants like dioxins and phosgene (produced by other techniques), and the products obtained can be reused in other industries. When compared to other precious metals, Pd/C catalyst exhibited a better catalytic activity. However, the catalyst showed a significant deactivation during the reaction. In this study, the oxidation state and particle size of Pd was monitored with time on stream in order to elucidate the transformations that the catalyst undergoes during HDC. The deactivation can be ascribed to the formation of a new PdC<i><sub>x</sub></i> phase during the first hour of reaction. Carbon atoms incorporated to Pd lattice come from (chloro)-hydrocarbons adsorbed in the metallic species, whose transformation is promoted by the HCl originating in the reaction. Nevertheless, the catalyst was regenerated by air flow treatment at 250 &#176;C, recovering the catalyst more than 80% of initial DCM conversion.
topic palladium
activated carbon
hydrodechlorination
deactivation
regeneration
palladium carbide
url https://www.mdpi.com/2073-4344/9/9/733
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