C. Durán-valle - Academia.edu (original) (raw)

Papers by C. Durán-valle

Research paper thumbnail of Activated carbons as catalyst in the synthesis of fine chemicals

espanolEl grupo de investigacion Quimica Sostenible y Medioambiental, perteneciente al Sistema Ex... more espanolEl grupo de investigacion Quimica Sostenible y Medioambiental, perteneciente al Sistema Extremeno de Ciencia y Tecnologia, se creo en el ano 2006 reuniendo a investigadores de diversas instituciones extremenas relacionadas con la investigacion y la innovacion. Dentro de sus lineas de trabajo, la mas importante en dedicacion y resultados es la utilizacion de carbones activados (CAs) quimicamente modificados como catalizadores en la sintesis de productos de alto valor anadido (PAVs). En este trabajo se muestran algunos de los resultados mas significativos obtenidos en esta linea de investigacion. EnglishThe group of research Sustainable and Environmental Chemistry, part of the Extremadura System of Science and Technology, was established in 2006 bringing together researchers from various institutions in Extremadura related to research and innovation. Within its lines of work, dedication and most important results is the use of activated carbons (CAs) chemically modified as cata...

Research paper thumbnail of Pilot Project for the Development of Public Speaking Skills in Students of 4TH Year for the Degree in Chemistry

EDULEARN16 Proceedings, 2016

Research paper thumbnail of Geometrical relationship between elemental composition and molecular size in carbonaceous materials

Applied Surface Science, 2006

Thermal treatment of carbonaceous materials shows two related phenomena: the graphene molecule (o... more Thermal treatment of carbonaceous materials shows two related phenomena: the graphene molecule (or carbon layer) increases in size and its carbon content also increases. In this work, a simple relationship between both effects was deducted, based on the structure geometry of carbonaceous materials. This relationship provides an approach to the mean size of graphene molecules which is more accurate than that acquired through different experimental techniques.

Research paper thumbnail of Developing Skills in Students of 4TH Year for the Degree in Chemistry Using a Scientific Article

EDULEARN16 Proceedings, 2016

Research paper thumbnail of Adsorption in Water Treatment

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, 2019

Research paper thumbnail of Recovery of grape waste for the preparation of adsorbents for water treatment: Mercury removal

Journal of Environmental Chemical Engineering, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Pore structure of chars and activated carbons prepared using carbon dioxide at different temperatures from extracted rockrose

Journal of Analytical and Applied Pyrolysis, 2001

This paper discusses the pore structure of chars and activated carbons prepared at different temp... more This paper discusses the pore structure of chars and activated carbons prepared at different temperatures from rockrose (Cistus ladaniferus L.), extracted previously into petroleum ether. The isothermal temperature of carbonization in nitrogen ranged from 600 to 1000°C. The starting char for activated carbons was prepared by treating a larger amount of precursor in the atmosphere formed as temperature increased from 30-600°C, at 10°C min − 1 , being the total heating time 120 min. This char was heated in nitrogen before activation, which was carried out using carbon dioxide at 700-950°C to 40% burn-off. Pycnometry (Hg, He), adsorption (N 2 , 77 K), mercury porosimetry and scanning electron microscopy techniques have been applied to the characterization. In the chars prepared in nitrogen, a shrinkage of the carbon structure is responsible for the pore narrowing in all the pore ranges, including a micropore closing above 800°C, which is attributed to the disappearance of ether groups. This shrinkage is less important in comparison with that occuring in chars prepared from rockrose without extraction. The starting char of the activated carbons presents a rudimentary pore structure due to the different conditions of its preparation. In the activated carbons, the pore volumes (micro, meso and macro) increase up to 750°C. At higher temperatures, the mesopore volume increases, whereas the micro-and macropore volumes decrease. These structural changes are discussed considering the starting char as a Ca-supported catalyst. A shrinkage of the carbon structure also occurs at high temperatures, without causing micropore closing.

Research paper thumbnail of FT-IR study of rockrose and of char and activated carbon

Journal of Analytical and Applied Pyrolysis, 1996

... Permissions & Reprints. FT-IR study of rockrose and of char and activated carbon. V. Gome... more ... Permissions & Reprints. FT-IR study of rockrose and of char and activated carbon. V. Gomez-Serrano Corresponding Author Contact Information , J. Pastor-Villegas , A. Perez-Florindo , C. Duran-Valle and C. Valenzuela-Calahorro. ... Active Carbon. Ellis Horwood. New York. ...

Research paper thumbnail of Activated carbon as a catalyst for the synthesis of N-alkylimidazoles and imidazolium ionic liquids

Catalysis Today, 2012

An activated carbon Norit RX3 has been treated with acids (sulphuric, nitric and sulphonitric mix... more An activated carbon Norit RX3 has been treated with acids (sulphuric, nitric and sulphonitric mixture). The modified activated carbons have been characterized by elemental analysis, point of zero charge, N 2 adsorption, XPS and FTIR. The solids obtained have been used as acidic heterogeneous catalyst in the reaction between imidazole and haloalkanes. The reaction with 1-bromobutane yields an ionic liquid, N,N-din -butyl-imidazolium bromide (1). Reaction with 2-bromobutane and 1-chlorohexane yields the corresponding N-alkyl-imidazoles (2) and (3). Sulphuric acid treated carbon is the most active catalyst.

Research paper thumbnail of Pore structure of activated carbons prepared by carbon dioxide and steam activation at different temperatures from extracted rockrose

Carbon, 2002

The influence of the activation temperature on the pore structure of granular activated carbons p... more The influence of the activation temperature on the pore structure of granular activated carbons prepared from rockrose (Cistus ladaniferus L.), extracted previously into petroleum ether, is comparatively studied. The preparation was carried out by pyrolysis of a char in nitrogen and its subsequent activation by carbon dioxide and steam (flow of water controlled to generate the same mol number per minute of water as well as carbon dioxide / nitrogen) at 700-9508C to 40% burn-off. The techniques applied to study the pore structure were: pycnometry (mercury, helium), adsorption (carbon dioxide, 298 K; nitrogen, 77 K), mercury porosimetry and scanning electron microscopy. The preparation by steam activation, especially at 7008C, yields activated carbons showing a total pore volume larger than those prepared by carbon dioxide activation. The pore structures present the greatest differences when the activations are carried out between 700 and 8508C and closer at higher temperatures. At high temperatures, the decrease of differences in pore development caused by carbon dioxide or steam is attributed to an external burn-off. The micropore structure of each activated carbon is mainly formed by wide micropores. At the lowest activation temperatures, especially at 7008C, steam develops the mesoporosity much more than carbon dioxide. At 9508C, a similar reduction of pore volume in the macropore range occurs.

Research paper thumbnail of Heat treatment of rockrose char in air. Effect on surface chemistry and porous texture

Carbon, 1996

... Abstract | PDF (1235 K) | View Record in Scopus | Cited By in Scopus (714). 4. KSW Sing, DHEv... more ... Abstract | PDF (1235 K) | View Record in Scopus | Cited By in Scopus (714). 4. KSW Sing, DHEverett, RAW Haul, L. Moscou, RA Pierotti, J. Rouquerol and T. Siemieniewska. Pure Appl. ... 8. J. Pastor-Villegas, C. Valenzuela-Calahorro, A. Bernalte-García and V. Gómez-Serrano. ...

Research paper thumbnail of Alkylation of imidazole under ultrasound irradiation over alkaline carbons

Applied Surface Science, 2006

N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane... more N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N 2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

Research paper thumbnail of Green chemistry: Efficient epoxides ring-opening with 1-butanol under microwave irradiation

Applied Surface Science, 2006

Two activated carbons treated with mineral acids (HNO 3 and sulfonitric mixture) have been tested... more Two activated carbons treated with mineral acids (HNO 3 and sulfonitric mixture) have been tested as acid catalysts in the epoxides (1,2epoxyhexane and styrene oxide) ring-opening reaction with 1-butanol under microwave (MW) irradiation. The mayor obtained product is that resulting of the alcohol addition to the most substituted carbon in the epoxide ring. The most active catalyst is that treated with sulfonitric mixture. The use of a MW oven allows achieving to the complete conversion of styrene oxide in only 2 min.

Research paper thumbnail of Formation of oxygen structures by air activation. A study by FT-IR spectroscopy

Carbon, 1999

Using cherry stones (CS) as starting material and commonly air as activating agent, formation of ... more Using cherry stones (CS) as starting material and commonly air as activating agent, formation of oxygen structures in activated carbon is investigated. In the preparation of samples, CS was first heated at temperatures between 450 and 9008C in N atmosphere. Then, in a successive activation stage, the product carbonized at 6008C was maintained in contact with an air 2 stream at 25-3258C for 24 h, 300-6008C for 1 h, and 2508C for 1-96 h. The rest of the carbonization products of CS were also heated at 2508C in air for 24 h. Moreover, the product carbonized at 9008C was activated at 750 or 9008C in CO for 1 2 h. Furthermore, in a second activation stage, the products activated at such temperatures in CO and those at 300-6008C in 2 air were heated at 2508C in air for 24 h. The starting material, carbonized products, and activated carbons were examined by FT-IR spectroscopy. A number of carbon-hydrogen atomic groupings and of oxygen groups and structures, i.e., OH, C=O, and CO -C) have been identified in CS. The yield of the activation and carbonization processes and also the chemical structure of the resultant products are strongly dependent on the carbonization temperature. In the products carbonized at 600-9008C, only ether type structures are detected. The activation at 2508C in air results in activated carbons that contain different oxygen structures when CS is carbonized at 450 or 6008C. At 750 or 900, by contrast, oxygen structures are not formed as a result of the activation treatment. This also applies when the carbonization product of CS at 9008C is activated solely in CO or first in CO and then in air. The heating conditions in air greatly influence the formation of oxygen 2 2 structures (specifically, of lactonic and ion-radical types) to a large extent. It only occurs when activating at relatively low temperatures for a long time; at 300-6008C for 1 h, however, the oxygen structures are not formed.

Research paper thumbnail of Functional porous carbons: Synthetic strategies and catalytic application in fine chemical synthesis

Emerging Carbon Materials for Catalysis, 2021

Abstract Porous carbon materials are considered extremely versatile and environmental friendly. T... more Abstract Porous carbon materials are considered extremely versatile and environmental friendly. These materials have found application in many and distinct fields such as energy generation and storage, water treatment including adsorption of emergent pollutants, NOx removal, biomedical engineering, and catalysis, among other research fields. Porous carbon is a long known material, but advances in material science, in solid state chemistry, and with technology constantly rendering new and more sophisticated equipment, these materials have witnessed constant development. The goal of this chapter is to provide an overview of the development and use of porous carbon materials showing very different structure, morphology, and composition focusing on their applications for fine chemical synthesis. A summarized presentation on the synthetic methodologies ranging from more traditional approaches to more modern and emergent porous carbons is then followed by a presentation of their applications in catalysis for fine chemical synthesis.

Research paper thumbnail of Hydrothermal Carbonisation: An Eco-Friendly Method for the Production of Carbon Adsorbents

Adsorption Processes for Water Treatment and Purification, 2017

The hydrothermal carbonisation process has attracted great interest in recent years, as it is an ... more The hydrothermal carbonisation process has attracted great interest in recent years, as it is an eco-friendly method for obtaining carbonaceous materials. This method consists of heating an organic material in the presence of water in a closed vessel at temperatures above 100 C. The pressure generated by the water vapour next to a heat supply gives rise to the reactions necessary to form hydrothermal carbon (HTC). This chapter describes the manufacture of these materials and their application as adsorbents of contaminants in the aqueous phase. The manufacturing method differs from the classic pyrolysis method because of its lower power consumption, higher yield, and drastic reduction of pollutant emissions. HTCs are chars with high oxygen content, a large number of functional groups, and low porous development. They have been used to remove numerous contaminants of all types, but they are especially suitable for the removal of heavy metals.

Research paper thumbnail of Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avocado seeds for biodiesel production from waste cooking oil

Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avoc... more Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avocado seeds for biodiesel production from waste cooking oil L. di Bitonto1*, H.E. Reynel-Ávila2, D.I. Mendoza-Castillo2, A. Bonilla-Petriciolet2, C.J. Durán-Valle3, C. Pastore1 1Water Research Institute (IRSA), National Research Council (CNR), via F. de Blasio 5, 70132 Bari, Italy 2Instituto Tecnológico de Aguascalientes, Av. Adolfo López Mateos #1801 Ote., Aguascalientes 20256, Mexico 3Department of Organic and Inorganic Chemistry and ACYS, Universidad de Extremadura, Avd. Elvas S/N, 06006 Badajoz, Spain

Research paper thumbnail of Radioactive characterization of charcoal as a tool in identifying fossil contamination

Journal of Radioanalytical and Nuclear Chemistry, 2018

In the pyrolysis process carried out to obtain charcoal from plants, a concentration of the radio... more In the pyrolysis process carried out to obtain charcoal from plants, a concentration of the radionuclides found in trace amounts in the raw material is produced. This fact would influence its possible uses. Radioactive characterization of a wide set of charcoal samples from different provenances was analysed. Activity concentrations of the radionuclides from the 238U and 232Th series, and also for 40K, 134Cs and 137Cs nuclides were obtained by gamma-ray and alpha-particle spectrometry. A discussion of these results is included comparing them with coal. A possible contamination of charcoal samples by fossil matter, such as coal, was studied via 14C analysis carried out by accelerator mass spectrometry.

Research paper thumbnail of Impact of water matrix and oxidant agent on the solar assisted photodegradation of a complex mix of pesticides over titania-reduced graphene oxide nanocomposites

Research paper thumbnail of Acidic porous carbons involved in the green and selective synthesis of benzodiazepines

Catalysis Today, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Activated carbons as catalyst in the synthesis of fine chemicals

espanolEl grupo de investigacion Quimica Sostenible y Medioambiental, perteneciente al Sistema Ex... more espanolEl grupo de investigacion Quimica Sostenible y Medioambiental, perteneciente al Sistema Extremeno de Ciencia y Tecnologia, se creo en el ano 2006 reuniendo a investigadores de diversas instituciones extremenas relacionadas con la investigacion y la innovacion. Dentro de sus lineas de trabajo, la mas importante en dedicacion y resultados es la utilizacion de carbones activados (CAs) quimicamente modificados como catalizadores en la sintesis de productos de alto valor anadido (PAVs). En este trabajo se muestran algunos de los resultados mas significativos obtenidos en esta linea de investigacion. EnglishThe group of research Sustainable and Environmental Chemistry, part of the Extremadura System of Science and Technology, was established in 2006 bringing together researchers from various institutions in Extremadura related to research and innovation. Within its lines of work, dedication and most important results is the use of activated carbons (CAs) chemically modified as cata...

Research paper thumbnail of Pilot Project for the Development of Public Speaking Skills in Students of 4TH Year for the Degree in Chemistry

EDULEARN16 Proceedings, 2016

Research paper thumbnail of Geometrical relationship between elemental composition and molecular size in carbonaceous materials

Applied Surface Science, 2006

Thermal treatment of carbonaceous materials shows two related phenomena: the graphene molecule (o... more Thermal treatment of carbonaceous materials shows two related phenomena: the graphene molecule (or carbon layer) increases in size and its carbon content also increases. In this work, a simple relationship between both effects was deducted, based on the structure geometry of carbonaceous materials. This relationship provides an approach to the mean size of graphene molecules which is more accurate than that acquired through different experimental techniques.

Research paper thumbnail of Developing Skills in Students of 4TH Year for the Degree in Chemistry Using a Scientific Article

EDULEARN16 Proceedings, 2016

Research paper thumbnail of Adsorption in Water Treatment

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, 2019

Research paper thumbnail of Recovery of grape waste for the preparation of adsorbents for water treatment: Mercury removal

Journal of Environmental Chemical Engineering, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Pore structure of chars and activated carbons prepared using carbon dioxide at different temperatures from extracted rockrose

Journal of Analytical and Applied Pyrolysis, 2001

This paper discusses the pore structure of chars and activated carbons prepared at different temp... more This paper discusses the pore structure of chars and activated carbons prepared at different temperatures from rockrose (Cistus ladaniferus L.), extracted previously into petroleum ether. The isothermal temperature of carbonization in nitrogen ranged from 600 to 1000°C. The starting char for activated carbons was prepared by treating a larger amount of precursor in the atmosphere formed as temperature increased from 30-600°C, at 10°C min − 1 , being the total heating time 120 min. This char was heated in nitrogen before activation, which was carried out using carbon dioxide at 700-950°C to 40% burn-off. Pycnometry (Hg, He), adsorption (N 2 , 77 K), mercury porosimetry and scanning electron microscopy techniques have been applied to the characterization. In the chars prepared in nitrogen, a shrinkage of the carbon structure is responsible for the pore narrowing in all the pore ranges, including a micropore closing above 800°C, which is attributed to the disappearance of ether groups. This shrinkage is less important in comparison with that occuring in chars prepared from rockrose without extraction. The starting char of the activated carbons presents a rudimentary pore structure due to the different conditions of its preparation. In the activated carbons, the pore volumes (micro, meso and macro) increase up to 750°C. At higher temperatures, the mesopore volume increases, whereas the micro-and macropore volumes decrease. These structural changes are discussed considering the starting char as a Ca-supported catalyst. A shrinkage of the carbon structure also occurs at high temperatures, without causing micropore closing.

Research paper thumbnail of FT-IR study of rockrose and of char and activated carbon

Journal of Analytical and Applied Pyrolysis, 1996

... Permissions & Reprints. FT-IR study of rockrose and of char and activated carbon. V. Gome... more ... Permissions & Reprints. FT-IR study of rockrose and of char and activated carbon. V. Gomez-Serrano Corresponding Author Contact Information , J. Pastor-Villegas , A. Perez-Florindo , C. Duran-Valle and C. Valenzuela-Calahorro. ... Active Carbon. Ellis Horwood. New York. ...

Research paper thumbnail of Activated carbon as a catalyst for the synthesis of N-alkylimidazoles and imidazolium ionic liquids

Catalysis Today, 2012

An activated carbon Norit RX3 has been treated with acids (sulphuric, nitric and sulphonitric mix... more An activated carbon Norit RX3 has been treated with acids (sulphuric, nitric and sulphonitric mixture). The modified activated carbons have been characterized by elemental analysis, point of zero charge, N 2 adsorption, XPS and FTIR. The solids obtained have been used as acidic heterogeneous catalyst in the reaction between imidazole and haloalkanes. The reaction with 1-bromobutane yields an ionic liquid, N,N-din -butyl-imidazolium bromide (1). Reaction with 2-bromobutane and 1-chlorohexane yields the corresponding N-alkyl-imidazoles (2) and (3). Sulphuric acid treated carbon is the most active catalyst.

Research paper thumbnail of Pore structure of activated carbons prepared by carbon dioxide and steam activation at different temperatures from extracted rockrose

Carbon, 2002

The influence of the activation temperature on the pore structure of granular activated carbons p... more The influence of the activation temperature on the pore structure of granular activated carbons prepared from rockrose (Cistus ladaniferus L.), extracted previously into petroleum ether, is comparatively studied. The preparation was carried out by pyrolysis of a char in nitrogen and its subsequent activation by carbon dioxide and steam (flow of water controlled to generate the same mol number per minute of water as well as carbon dioxide / nitrogen) at 700-9508C to 40% burn-off. The techniques applied to study the pore structure were: pycnometry (mercury, helium), adsorption (carbon dioxide, 298 K; nitrogen, 77 K), mercury porosimetry and scanning electron microscopy. The preparation by steam activation, especially at 7008C, yields activated carbons showing a total pore volume larger than those prepared by carbon dioxide activation. The pore structures present the greatest differences when the activations are carried out between 700 and 8508C and closer at higher temperatures. At high temperatures, the decrease of differences in pore development caused by carbon dioxide or steam is attributed to an external burn-off. The micropore structure of each activated carbon is mainly formed by wide micropores. At the lowest activation temperatures, especially at 7008C, steam develops the mesoporosity much more than carbon dioxide. At 9508C, a similar reduction of pore volume in the macropore range occurs.

Research paper thumbnail of Heat treatment of rockrose char in air. Effect on surface chemistry and porous texture

Carbon, 1996

... Abstract | PDF (1235 K) | View Record in Scopus | Cited By in Scopus (714). 4. KSW Sing, DHEv... more ... Abstract | PDF (1235 K) | View Record in Scopus | Cited By in Scopus (714). 4. KSW Sing, DHEverett, RAW Haul, L. Moscou, RA Pierotti, J. Rouquerol and T. Siemieniewska. Pure Appl. ... 8. J. Pastor-Villegas, C. Valenzuela-Calahorro, A. Bernalte-García and V. Gómez-Serrano. ...

Research paper thumbnail of Alkylation of imidazole under ultrasound irradiation over alkaline carbons

Applied Surface Science, 2006

N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane... more N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N 2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

Research paper thumbnail of Green chemistry: Efficient epoxides ring-opening with 1-butanol under microwave irradiation

Applied Surface Science, 2006

Two activated carbons treated with mineral acids (HNO 3 and sulfonitric mixture) have been tested... more Two activated carbons treated with mineral acids (HNO 3 and sulfonitric mixture) have been tested as acid catalysts in the epoxides (1,2epoxyhexane and styrene oxide) ring-opening reaction with 1-butanol under microwave (MW) irradiation. The mayor obtained product is that resulting of the alcohol addition to the most substituted carbon in the epoxide ring. The most active catalyst is that treated with sulfonitric mixture. The use of a MW oven allows achieving to the complete conversion of styrene oxide in only 2 min.

Research paper thumbnail of Formation of oxygen structures by air activation. A study by FT-IR spectroscopy

Carbon, 1999

Using cherry stones (CS) as starting material and commonly air as activating agent, formation of ... more Using cherry stones (CS) as starting material and commonly air as activating agent, formation of oxygen structures in activated carbon is investigated. In the preparation of samples, CS was first heated at temperatures between 450 and 9008C in N atmosphere. Then, in a successive activation stage, the product carbonized at 6008C was maintained in contact with an air 2 stream at 25-3258C for 24 h, 300-6008C for 1 h, and 2508C for 1-96 h. The rest of the carbonization products of CS were also heated at 2508C in air for 24 h. Moreover, the product carbonized at 9008C was activated at 750 or 9008C in CO for 1 2 h. Furthermore, in a second activation stage, the products activated at such temperatures in CO and those at 300-6008C in 2 air were heated at 2508C in air for 24 h. The starting material, carbonized products, and activated carbons were examined by FT-IR spectroscopy. A number of carbon-hydrogen atomic groupings and of oxygen groups and structures, i.e., OH, C=O, and CO -C) have been identified in CS. The yield of the activation and carbonization processes and also the chemical structure of the resultant products are strongly dependent on the carbonization temperature. In the products carbonized at 600-9008C, only ether type structures are detected. The activation at 2508C in air results in activated carbons that contain different oxygen structures when CS is carbonized at 450 or 6008C. At 750 or 900, by contrast, oxygen structures are not formed as a result of the activation treatment. This also applies when the carbonization product of CS at 9008C is activated solely in CO or first in CO and then in air. The heating conditions in air greatly influence the formation of oxygen 2 2 structures (specifically, of lactonic and ion-radical types) to a large extent. It only occurs when activating at relatively low temperatures for a long time; at 300-6008C for 1 h, however, the oxygen structures are not formed.

Research paper thumbnail of Functional porous carbons: Synthetic strategies and catalytic application in fine chemical synthesis

Emerging Carbon Materials for Catalysis, 2021

Abstract Porous carbon materials are considered extremely versatile and environmental friendly. T... more Abstract Porous carbon materials are considered extremely versatile and environmental friendly. These materials have found application in many and distinct fields such as energy generation and storage, water treatment including adsorption of emergent pollutants, NOx removal, biomedical engineering, and catalysis, among other research fields. Porous carbon is a long known material, but advances in material science, in solid state chemistry, and with technology constantly rendering new and more sophisticated equipment, these materials have witnessed constant development. The goal of this chapter is to provide an overview of the development and use of porous carbon materials showing very different structure, morphology, and composition focusing on their applications for fine chemical synthesis. A summarized presentation on the synthetic methodologies ranging from more traditional approaches to more modern and emergent porous carbons is then followed by a presentation of their applications in catalysis for fine chemical synthesis.

Research paper thumbnail of Hydrothermal Carbonisation: An Eco-Friendly Method for the Production of Carbon Adsorbents

Adsorption Processes for Water Treatment and Purification, 2017

The hydrothermal carbonisation process has attracted great interest in recent years, as it is an ... more The hydrothermal carbonisation process has attracted great interest in recent years, as it is an eco-friendly method for obtaining carbonaceous materials. This method consists of heating an organic material in the presence of water in a closed vessel at temperatures above 100 C. The pressure generated by the water vapour next to a heat supply gives rise to the reactions necessary to form hydrothermal carbon (HTC). This chapter describes the manufacture of these materials and their application as adsorbents of contaminants in the aqueous phase. The manufacturing method differs from the classic pyrolysis method because of its lower power consumption, higher yield, and drastic reduction of pollutant emissions. HTCs are chars with high oxygen content, a large number of functional groups, and low porous development. They have been used to remove numerous contaminants of all types, but they are especially suitable for the removal of heavy metals.

Research paper thumbnail of Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avocado seeds for biodiesel production from waste cooking oil

Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avoc... more Synthesis, characterization and applications of carbon-based calcium catalysts deriving from avocado seeds for biodiesel production from waste cooking oil L. di Bitonto1*, H.E. Reynel-Ávila2, D.I. Mendoza-Castillo2, A. Bonilla-Petriciolet2, C.J. Durán-Valle3, C. Pastore1 1Water Research Institute (IRSA), National Research Council (CNR), via F. de Blasio 5, 70132 Bari, Italy 2Instituto Tecnológico de Aguascalientes, Av. Adolfo López Mateos #1801 Ote., Aguascalientes 20256, Mexico 3Department of Organic and Inorganic Chemistry and ACYS, Universidad de Extremadura, Avd. Elvas S/N, 06006 Badajoz, Spain

Research paper thumbnail of Radioactive characterization of charcoal as a tool in identifying fossil contamination

Journal of Radioanalytical and Nuclear Chemistry, 2018

In the pyrolysis process carried out to obtain charcoal from plants, a concentration of the radio... more In the pyrolysis process carried out to obtain charcoal from plants, a concentration of the radionuclides found in trace amounts in the raw material is produced. This fact would influence its possible uses. Radioactive characterization of a wide set of charcoal samples from different provenances was analysed. Activity concentrations of the radionuclides from the 238U and 232Th series, and also for 40K, 134Cs and 137Cs nuclides were obtained by gamma-ray and alpha-particle spectrometry. A discussion of these results is included comparing them with coal. A possible contamination of charcoal samples by fossil matter, such as coal, was studied via 14C analysis carried out by accelerator mass spectrometry.

Research paper thumbnail of Impact of water matrix and oxidant agent on the solar assisted photodegradation of a complex mix of pesticides over titania-reduced graphene oxide nanocomposites

Research paper thumbnail of Acidic porous carbons involved in the green and selective synthesis of benzodiazepines

Catalysis Today, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.