Artículos de revistas: "Contenu en carbone"

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Van Ryckeghem, S. "Caractérisation des formes physico-chimiques des deux radionucléides principaux (18F et 11C) produits par irradiation de cible et du principal radionucléide parasite (13N) rejetés par les installations françaises de fabrication de radiopharmaceutiques au moyen d’un cyclotron". Radioprotection 56, n.º 2 (abril de 2021): 127–35. http://dx.doi.org/10.1051/radiopro/2021008.

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Cette étude, réalisée par l’IRSN (Institut de Radioprotection et de Sûreté Nucléaire) dans le cadre d’une demande de l’ASN (Autorité de Sûreté Nucléaire), concerne la caractérisation des formes physico-chimiques des composés radioactifs rejetés par les installations françaises de fabrication de radiopharmaceutiques au moyen d’un cyclotron. Elle vise à disposer d’une meilleure connaissance sur les effluents gazeux radioactifs rejetés par ces installations. Cette étude porte sur les deux principaux radionucléides produits par irradiation d’une cible à des fins de fabrication de radiopharmaceutiques : le fluor 18 (18F) et le carbone 11 (11C). L’azote 13 (13N), principal radionucléide parasite produit dans la cible et relâché essentiellement lors du transfert du contenu de cette dernière vers le laboratoire de radiochimie, a également été étudié.

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Duru, Michel, Jean-Pierre Sarthou y Olivier Therond. "L’agriculture régénératrice : summum de l’agroécologie ou greenwashing?" Cahiers Agricultures 31 (2022): 17. http://dx.doi.org/10.1051/cagri/2022014.

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Face aux nombreux défis sociétaux à relever (environnement, sécurité alimentaire, santé), différentes formes d’agriculture sont envisagées. Agriculture biologique, agriculture de conservation des sols et maintenant agriculture régénératrice sont trois récits fondateurs se référant à l’agroécologie. Toutefois, l’agriculture régénératrice, nouvelle arrivée en France, reste ambiguë. Nous proposons un cadre d’analyse des formes d’agriculture en termes d’impacts et de services, que nous mobilisons pour comparer l’agriculture régénératrice à celles auxquelles elle se réfère et qui sont bien documentées dans la littérature scientifique. Cette analyse permet d’éclairer des points critiques de l’agriculture régénératrice tels que la question des pesticides et du niveau de séquestration du carbone dans les sols. Ensuite, nous identifions les atouts, faiblesses, opportunités et menaces pour le changement d’échelle de cette agriculture. Nous montrons qu’un atout majeur de l’agriculture régénératrice est de reposer sur un récit mettant en avant un principe, la « régénération » des biens communs (sols, eau, air, biodiversité), qui peut entraîner l’adhésion d’une diversité d’acteurs. Cependant, la mobilisation des acquis de l’agroécologie, en tant que science, pratique et mouvement, pourrait aider à préciser son contenu, encore flou, de façon à ce que ses promesses se traduisent en de réels progrès et ne soient pas exclusivement centrés sur le carbone.

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Oualit, Mehena, Amar Irekti y Arezki Sarri. "Influence des conditions de durcissement et le taux d’alcalins sur les performances mécaniques des matériaux alcali-activés à base du laitier de haut fourneau". Matériaux & Techniques 110, n.º 2 (2022): 202. http://dx.doi.org/10.1051/mattech/2022017.

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Dans un monde qui s’oriente davantage vers le développement durable, les matériaux alcali-activés (MAA) sont identifiés comme étant une alternative aux matériaux à base cimentaire, connus pour leur forte émission de CO2 lors de leur fabrication. Bien que des efforts soient fournis pour minimiser cet impact négatif sur l’environnement par l’utilisation de sous-produits industriels lors de la fabrication du ciment Portland ou par substitution partielle du ciment dans la formulation du béton, le crédit carbone reste toutefois élevé. La présente étude vise à évaluer les propriétés mécaniques d’un matériau alcali-activé à base du laitier granulé de haut fourneau. L’activation alcaline a été réalisée par deux types d’activants à savoir une solution aqueuse de silicate de sodium et une solution d’hydroxyde de sodium à différentes concentrations molaires. Les résultats ont montré que le taux d’alcalin contenu dans l’activant ainsi que les conditions de durcissement des échantillons influe significativement sur les performances mécaniques des matériaux alcali-activés élaborés. La valeur de la résistance à la compression la plus élevée est estimée à 117 MPa, enregistrée à 28 jours de durcissement sous conditions contrôlées (humidité = 50 % ; T° = 20 °C), et ce, en utilisant un taux de silicate alcalin égal à 6 (exprimé en pourcentage de Na2O par rapport au précurseur).

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Oualit, Mehena, Amar Irekti y Arezki Sarri. "Influence des conditions de durcissement et le taux d’alcalins sur les performances mécaniques des matériaux alcali-activés à base du laitier de haut fourneau". Matériaux & Techniques 110, n.º 2 (2022): 202. http://dx.doi.org/10.1051/mattech/2022017.

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Dans un monde qui s’oriente davantage vers le développement durable, les matériaux alcali-activés (MAA) sont identifiés comme étant une alternative aux matériaux à base cimentaire, connus pour leur forte émission de CO2 lors de leur fabrication. Bien que des efforts soient fournis pour minimiser cet impact négatif sur l’environnement par l’utilisation de sous-produits industriels lors de la fabrication du ciment Portland ou par substitution partielle du ciment dans la formulation du béton, le crédit carbone reste toutefois élevé. La présente étude vise à évaluer les propriétés mécaniques d’un matériau alcali-activé à base du laitier granulé de haut fourneau. L’activation alcaline a été réalisée par deux types d’activants à savoir une solution aqueuse de silicate de sodium et une solution d’hydroxyde de sodium à différentes concentrations molaires. Les résultats ont montré que le taux d’alcalin contenu dans l’activant ainsi que les conditions de durcissement des échantillons influe significativement sur les performances mécaniques des matériaux alcali-activés élaborés. La valeur de la résistance à la compression la plus élevée est estimée à 117 MPa, enregistrée à 28 jours de durcissement sous conditions contrôlées (humidité = 50 % ; T° = 20 °C), et ce, en utilisant un taux de silicate alcalin égal à 6 (exprimé en pourcentage de Na2O par rapport au précurseur).

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De Cara, Stéphane y Pierre-Alain Jayet. "Évaluation et régulation de l’effet de serre d’origine agricole". Articles 75, n.º 4 (9 de febrero de 2009): 597–623. http://dx.doi.org/10.7202/602304ar.

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RÉSUMÉNous examinons la contribution du secteur agricole aux émissions de gaz à effet de serre ainsi que l’impact de mesures de régulation. À partir d’un modèle économique de l’offre agricole française à fort contenu technique, nous mesurons la contribution des activités animales et végétales à l’accumulation de méthane et de protoxyde d’azote et au stockage du carbone dans le sol et la partie aérienne des plantes. Nous donnons ensuite un éclairage prospectif sur la réaction à court et moyen terme de l’offre agricole à l’application de différents schémas de taxation. Dans un premier temps, nous donnons une appréciation de l’impact d’un schéma de premier rang et discutons de l’intérêt d’une incitation au reboisement des terres en jachère. Basées sur les données techniques disponibles, les taxes et primes reposent directement sur les niveaux d’émissions que l’agence environnementale est supposée mesurer parfaitement. Dans une optique de second rang fondée sur la taxation de facteurs observables à moindre coût, nous examinons ensuite l’effet : (i) d’une taxe sur l’alimentation achetée et (ii) d’une taxe sur l’animal. Le principal résultat est que l’incitation au reboisement constitue un instrument efficace de régulation de l’effet de serre d’origine agricole, alors que les schémas de taxe de second rang sur l’activité de production animale apparaissent relativement inefficaces.

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Lescuyer, Guillaume y Julienne Nadège Essoungou. "Gestion forestière multi-usages en Afrique centrale : perceptions, mises en oeuvre et évolutions". BOIS & FORETS DES TROPIQUES 315, n.º 315 (1 de marzo de 2013): 29. http://dx.doi.org/10.19182/bft2013.315.a20536.

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Quoique la gestion forestière multiusages (Gfmu) soit promue par les codes forestiers d'Afrique centrale, cette approche reste mal comprise et peu mise en oeuvre pour les forêts de production et les forêts communautaires. L'article présente les résultats de 62 entretiens avec des personnes impliquées dans la gestion forestière au Cameroun, au Gabon et en République démocratique du Congo, et fait ressortir trois interprétations de la Gfmu : une exploitation durable du bois intégrant secondairement les usages des autres acteurs ; une utilisation coutumière des ressources par les populations locales ; une gestion planifiée et formelle de la diversité des biens et fonctions fournis par ces écosystèmes. L'analyse détaillée de huit études de cas montre en pratique que l'aménagement durable de la forêt se focalise presque toujours sur l'exploitation du bois ; quoique l'utilisation du gibier et la collecte des produits forestiers non ligneux soient systématiquement mentionnés dans les documents d'aménagement. À l'inverse, les services environnementaux - séquestration du carbone, protection des bassins versants - ou les biens publics y sont quasi absents. L'inscription de différents usages dans les documents de gestion ne suffit toutefois pas pour qu'ils soient toujours mis en oeuvre sur le terrain. Trois pistes sont explorées pour renforcer l'application de la Gfmu dans le bassin du Congo : concevoir la Gfmu à l'échelle du paysage et non à celle du massif forestier ; améliorer le contenu des documents d'aménagement forestier pour y inclure et valoriser l'ensemble des usages de la forêt ; renforcer le contrôle de l'application effective des documents de gestion, grâce à la certification ou à un meilleur contrôle du respect de la légalité.

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Saulnier-Talbot, Émilie y Reinard Pienitz. "Isolation au postglaciaire d'un bassin côtier près de Kuujjuaraapik-Whapmagoostui, en Hudsonie (Québec) : une analyse biostratigraphique diatomifère". Géographie physique et Quaternaire 55, n.º 1 (2 de octubre de 2002): 63–74. http://dx.doi.org/10.7202/005662ar.

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Résumé En vue de retracer les phases d'isolation postglaciaire d'un lac côtier situé près de Kuujjuaraapik-Whapmagoostui (baie d'Hudson), le contenu diatomifère d'une carotte de sédiments a été analysé. La séquence sédimentaire recueillie dans le lac Kachishayoot démontre trois unités de changements paléoenvironnementaux provoqués par le relèvement isostatique postglaciaire. Ces unités se distinguent entre elles par une sédimentologie et des assemblages fossiles de diatomées contrastants. Le passage de l'argile marine à la gyttja et l'évolution des assemblages diatomifères successivement dominés par des espèces poly-mésohalobes, oligohalobes, puis halophobes, démontrent bien les effets de la salinité décroissante sur le milieu aquatique. De plus, les valeurs décroissantes d'alcalinité calculées par l'intermédiaire d'une fonction de transfert (basée sur les assemblages de diatomées) reflètent le passage d'un environnement riche à un environnement pauvre en nutriments lors de l'isolation du bassin lacustre des eaux de la Mer postglaciaire de Tyrrell. Le recyclage graduel de ses eaux a ainsi éliminé les nutriments et les ions majeurs (carbone inorganique dissous, Ca, Mg) issus du délavement du till et des argiles marines. La datation, par spectrométrie de masse à l'aide d'un accélérateur de particules (SMA) de matériel provenant de la carotte a permis d'évaluer le taux de sédimentation et d'estimer la durée des trois différentes étapes de la succession lacustre dans le bassin du lac Kachishayoot (conditions marines de 5400-4500 ans cal. BP, phase d'isolation entre 4500-1600 ans cal. BP et la phase lacustre depuis 1600 ans cal. BP). Cette étude biostratigraphique fournit aussi des indices quant à l'évolution du paysage dans le sud de l'Hudsonie par suite du retrait de la Mer postglaciaire de Tyrrell, il y a environ 5000 ans.

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Tallian, Kimberly B., Milap C. Nahata y Chang-Yong Tsao. "Role of the Ketogenic Diet in Children with Intractable Seizures". Annals of Pharmacotherapy 32, n.º 3 (marzo de 1998): 349–61. http://dx.doi.org/10.1345/aph.16245.

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OBJECTIVE: To provide a review of the mechanism of action, clinical efficacy, adverse effects, drug interactions, and therapeutic considerations associated with the use of a ketogenic diet to manage patients with intractable seizures. DATA SOURCES: A MEDLINE search from January 1966 to the present and relevant articles from journals were reviewed. DATA SYNTHESIS: The ketogenic diet has been used as a treatment modality since the early 1920s to control intractable seizures. The exact mechanism of action is unknown. Overall, uncontrolled clinical studies have reported that approximately one-third of patients with intractable seizures have become seizure-free on the ketogenic diet. Common adverse events attributed to the diet include dehydration, gastrointestinal symptoms, hypoglycemia, as well as carnitine and vitamin deficiencies. Cognitive effects, hyperlipidemia, impaired neutrophil function, urolithiasis, optic neuropathy, osteoporosis, and protein deficiency may also occur in some patients. Carbohydrate content and drug formulation in the selection of medications while on the diet are important. Acetazolamide, phenobarbital, and valproic acid have been reported to interact with the ketogenic diet. Medications that cause carnitine deficiency or influence carbohydrate metabolism should also be used with caution. The carbohydrate content of drugs in various therapeutic classes is presented to aid in the selection of the most appropriate drug and formulation for patients on the ketogenic diet. The success of the diet in controlling intractable seizures is related to the patient's close adherence to the diet. Minimizing carbohydrate ingestion from medications along with a multidisciplinary team approach to the selection and monitoring of the diet are important to the success of the ketogenic diet in controlling seizures. CONCLUSIONS: The ketogenic diet has shown promising results in controlling intractable seizures; however, carefully controlled clinical trials are needed to better assess the efficacy of the diet during its use and after discontinuation. OBJETIVO: Revisar el mecanismo de acción, la eficacia clínica, los efectos adversos, interacciones con drogas, y las consideraciones terapéuticas asociadas al uso de una dieta cetogénica para el manejo de pacientes con convulsiones intratables. FUENTES DE INFORMACIÓN: A través del sistema MEDLINE desde 1966 al presente. Se revisaron articulos pertinentes. SÍNTESIS: La dieta cetogénica se ha estado usando como modalidad de tratamiento para las convulsiones incoercibles desde el principio de los años 1920. Se desconoce el mecanismo exacto de acción. En general, estudios clínicos no controlados han informado que alrededor de un tercio de los pacientes con convulsiones intratables llegan a estar sin convulsiones mientras llevan la dieta cetogénica. Entre los efectos adversos que se atribuyen a esta dieta están: deshidratación, síntomas gastrointestinales, hipoglicemia, y deficiencias de vitaminas y carnitina. En algunos pacientes también se pueden manifestar efectos del conocimiento, hiperlipidemia, función defectuosa de los neutrófilos, producción de piedras renales, neuropatía óptica, osteoporosis, y deficiencia de proteinas. La dieta cetogénica se originó del principio de que la inanición ejerce efectos anticonvulsivos, y que una dieta alta en grasas y baja en carbohidratos podría imitar el ayuno. Durante los años 1940 y 1950 y con el advenimiento de las drogas anticonvulsantes esta dieta se consideró voodoo. En 1971, Huttenlocher et al. presentaron una dieta alterna que usaba un aceite insaboro, incoloro, e inodoro, que proveía el 60% de las calorias diarias como triglicéridos de cadena mediana. Esta dieta fue modificada luego para combinar triglicéridos de cadena mediana (30%) con de cadena larga (41%) y se le añadió agua y gelatina para formar una emulsión. La dieta cetogénica ha recuperado popularidad en los Estados Unidos como alternativa a las drogas anticonvulsantes en pacientes que no responden o que experimentan efectos adversos a las drogas. En este artículo se discute la importancia del contenido de carbohidratos y de la formulación de la droga al escoger medicamentos mientras se mantiene la dieta cetogénica. Se deben utilizar con cuidado los medicamentos que causen deficiencia de carnitina, así como los que influyen el metabolismo de carbohidratos. Se incluye el contenido de carbohidratos de algunos medicamentos para ayudar al lector al seleccionar la droga y la formulación más apropiada para los pacientes que estén en la dieta cetogénica. El éxito de ésta en controlar las convulsiones incoercibles depende mucho de la adhesión del paciente a la dieta. CONCLUSIONES: La dieta cetogénica ha mostrado resultados prometedores para controlar las convulsiones intratables, no obstante, se necesitan estudios clínicos cuidadosamente controlados para poder evaluar mejor la eficacia de la dieta durante su uso y después de descontinuarse. OBJECTIF: Réviser le mécanisme d'action, l'efficacité clinique, les effets indésirables, les interactions médicamenteuses, et les considérations d'ordre thérapeutique associés à l'emploi d'une diète cétogène visant à mieux traiter les patients atteints de convulsions réfractaires. REVUE DE LITTÉRATURE: Une recherche de la banque de données MEDLINE 1966 à aujourd'hui a permis l'identification d'articles pertinents. RÉSUMÉ: La diète cétogène est employée dans le traitement des convulsions réfractaires depuis le début des années 1920. Le mécanisme d'action exact demeure inconnu. Des études cliniques non-contrôlées ont suggéré qu'approximativement un tiers des patients atteints de convulsions réfractaires au traitement sont contrôlés par l'emploi d'une diète cétogène. Les effets secondares communs attribués à cette diète sont les suivants: déshydratation, symptômes gastro-intestinaux, hypoglycémie, de même que des déficiences en vitamines et en carnitine. Des effets cognitifs, de l'hyperlipidémie, une altération fonctionnelle des neutrophiles, la production de lithiase rénale, une neuropathie optique, de l'ostéoporose, et une déficience protéinique peuvent également survenir chez certains patients. Le contenu en hydrates de carbone et la formulation pharmaceutique des médicaments administrés aux patients soumis à cette diète sont des paramètres importants discutés. On a rapporté que l'acétazolamide, le phénobarbital, et l'acide valproïque peuvent interagir avec la diète cétogène. Les médicaments pouvant causer une déficience en carnitine ou pouvant altérer le métabolisme des hydrates de carbone devraient également être utilisés avec précaution. Les auteurs présentent un tableau du contenu en hydrates de carbone des médicaments selon les diverses classes thérapeutiques employées, et ce afin d'aider le clinicien lors de la sélection du médicament et de sa formulation pharmaceutique les plus appropriés pour les patients soumis à une diète cétogène. Le succès thérapeutique de ce type de diète dépend du degré de fidélité du patient à sa diète. Pour obtenir un contrôle optimal des convulsions réfractaires, il est important de minimiser l'ingestion d'hydrates de carbone provenant de la médication, de même que de développer une approche multidisciplinaire permettant une meilleure sélection et un suivi adéquat de la diète. CONCLUSIONS: La diète cétogène a démontré des résultats prometteurs dans le contrôle des convulsions réfractaires; toutefois, des études cliniques contrôlées et bien conçues sont requises afin de mieux évaluer l'efficacité de cette diète en cours d'utilisation, de même qu'après son arrêt.

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Cienciala, E., Z. Exnerová, J. Macků y V. Henžlík. "Foresttopsoil organic carbon content inSouthwest Bohemiaregion". Journal of Forest Science 52, No. 9 (9 de enero de 2012): 387–98. http://dx.doi.org/10.17221/4519-jfs.

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The aim of this study was to evaluate organic carbon content (SOC) in the surface layers of forest soils in the two Natural Forest Regions situated in Southwest Bohemia, namely Západočeská pahorkatina (NFR 6) and Český les (NFR 11). The study is based upon on two consecutive soil sampling campaigns during autumn 2003 and 2004. While the sampling of 2003 was inadequate to estimate bulk density, the consecutive campaign used a defined sample volume to permit an estimation of bulk density and quantification of soil organic carbon (SOC) for soil organic layers and the upper mineral horizon. The total sampling depth was 30 cm including both organic and mineral layer. SOC of organic horizon was on average 1.99 kg C/m2. It differed by stand site type ranging from 0.70 to 3.04 kg C/m2. The organic layer SOC was smallest under beech (1.03 kg C/m2), whereas it was higher under pine (2.19 kg C/m2) and spruce (2.09 kg C/m2). SOC in the mineral layer was in average 7.28 kg C/m2. SOC differed significantly by the major tree species and reached 10.6; 5.67 and 7.5 kg C/m2 for beech, pine and spruce sites, respectively. The average SOC for the total soil layer (0–30 cm) reached 9.33 kg C/m2. The methodological aspects of regional estimation of SOC and the potential of utilization of the national forest inventory program are also discussed.

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Villalgordo-Hernández, David, Aida Grau-Atienza, Antonio A. García-Marín, Enrique V. Ramos-Fernández y Javier Narciso. "Manufacture of Carbon Materials with High Nitrogen Content". Materials 15, n.º 7 (25 de marzo de 2022): 2415. http://dx.doi.org/10.3390/ma15072415.

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Nowadays one of the biggest challenges for carbon materials is their use in CO2 capture and their use as electrocatalysts in the oxygen reduction reaction (ORR). In both cases, it is necessary to dope the carbon with nitrogen species. Conventional methods to prepare nitrogen doped carbons such as melamine carbonization or NH3 treatment generate nitrogen doped carbons with insufficient nitrogen content. In the present research, a series of activated carbons derived from MOFs (ZIF-8, ZIF-67) are presented. Activated carbons have been prepared in a single step, by pyrolysis of the MOF in an inert atmosphere, between 600 and 1000 °C. The carbons have a nitrogen content up to 20 at.% and a surface area up to 1000 m2/g. The presence of this nitrogen as pyridine or pyrrolic groups, and as quaternary nitrogen are responsible for the great adsorption capacity of CO2, especially the first two. The presence of Zn and Co generates very different carbonaceous structures. Zn generates a greater porosity development, which makes the doped carbons ideal for CO2 capture. Co generates more graphitized doped carbons, which make them suitable for their use in electrochemistry.

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Saha, Dipendu, Gerassimos Orkoulas y Dean Bates. "One-Step Synthesis of Sulfur-Doped Nanoporous Carbons from Lignin with Ultra-High Surface Area, Sulfur Content and CO2 Adsorption Capacity". Materials 16, n.º 1 (3 de enero de 2023): 455. http://dx.doi.org/10.3390/ma16010455.

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Lignin is the second-most available biopolymer in nature. In this work, lignin was employed as the carbon precursor for the one-step synthesis of sulfur-doped nanoporous carbons. Sulfur-doped nanoporous carbons have several applications in scientific and technological sectors. In order to synthesize sulfur-doped nanoporous carbons from lignin, sodium thiosulfate was employed as a sulfurizing agent and potassium hydroxide as the activating agent to create porosity. The resultant carbons were characterized by pore textural properties, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The nanoporous carbons possess BET surface areas of 741–3626 m2/g and a total pore volume of 0.5–1.74 cm3/g. The BET surface area of the carbon was one of the highest that was reported for any carbon-based materials. The sulfur contents of the carbons are 1–12.6 at.%, and the key functionalities include S=C, S-C=O, and SOx. The adsorption isotherms of three gases, CO2, CH4, and N2, were measured at 298 K, with pressure up to 1 bar. In all the carbons, the adsorbed amount was highest for CO2, followed by CH4 and N2. The equilibrium uptake capacity for CO2 was as high as ~11 mmol/g at 298 K and 760 torr, which is likely the highest among all the porous carbon-based materials reported so far. Ideally adsorbed solution theory (IAST) was employed to calculate the selectivity for CO2/N2, CO2/CH4, and CH4/N2, and some of the carbons reported a very high selectivity value. The overall results suggest that these carbons can potentially be used for gas separation purposes.

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Nabih, Meryem Hajji, Hamza Boulika, Maryam Elhajam, Noureddine Idrissi Kandri y Abdelaziz Zerouale. "Synthesis of an Activated Carbon Based on Cardoon Waste and its Comparison to a Commercial Carbon in Terms of Physicochemical Characterization and Organic Dye Adsorption Performance". Key Engineering Materials 954 (31 de agosto de 2023): 41–54. http://dx.doi.org/10.4028/p-wyfpo4.

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The present study aims to evaluate the possibility of using low-cost adsorbents based on Cardoon waste for the depollution of industrial effluents. After characterization of the raw cardoon waste [1], the carbonization was carried out at 350 °C in a muffle furnace. In order to show the performance of the method used to prepare this activated carbon (PC), a comparative study with a commercial carbon (CC) is performed. The obtained activated carbon and the commercial carbon were characterized by thermogravimetric analysis, scanning electron microscopy coupled with EDX, X-ray diffraction, Fourier transform infrared absorption spectroscopy and inductively coupled plasma atomic emission spectroscopy. Approximate analyses of moisture content, volatile matter content, ash content and fixed carbon content, acid-base surface functions, pH at zero charge and iodine value were performed. The obtained results indicate that the main characteristics of the activated carbon prepared at 350 °C are practically similar to those of the commercial carbon; a homogeneous porous surface, an interesting percentage of carbon, a high thermal stability and a disorganized graphitic crystalline structure, the iodine adsorption values on the two carbons are 409.887 mg/g for PC and 430.191 mg/g for CC. The adsorption of methylene blue (MB) on both carbons was performed. The kinetics and isotherms of MB adsorption on the two carbons were evaluated. According to the obtained results, the use of the prepared carbon in effluent treatment can be put into perspective.

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Diamadopoulos, E., P. Samaras y G. P. Sakellaropoulos. "The Effect of Activated Carbon Properties on the Adsorption of Toxic Substances". Water Science and Technology 25, n.º 1 (1 de enero de 1992): 153–60. http://dx.doi.org/10.2166/wst.1992.0023.

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The objectives of this work were to relate the activated carbon properties to its adsorptive capacity. The activated carbon needed was produced in the lab from Greek lignite coal. Subsequently, adsorption studies were performed in order to evaluate the efficiency of the various activated carbons to remove toxic substances from water. Two organic substances were used. These were phenol and fulvic acid. Additionally, the adsorption of arsenic (V) was, also, investigated. It was found that the adsorptive capacity of the activated carbons depended primarily on the ash content and the compound. The capacity of the carbon to remove phenol, expressed as mg of phenol removed per g of activated carbon (carbon loading), decreased linearly as the amount of ash in the activated carbon increased. Ash-free activated carbons could adsorb 4 times as much phenol as the activated carbons with a high ash content. On the other hand, fulvic acid and arsenic adsorbed poorly on the ash-free activated carbons. Even for the high surface area activated carbons (over 1000 m2/g), the quantity of fulvic acid or arsenic adsorbed was significantly less than that exhibited by the high ash activated carbons (maximum surface area measured hardly exceeded 300 m2/g). As the amount of ash in the carbon increased, the carbon loading increased as well, up to a certain level, beyond which the amount of ash played no significant role. The beneficial role of ash was explained by the ability of the fulvic acid and arsenic to interact with metal oxides and metal ions, which constitute a significant fraction of the ash.

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Shahrukh, Akhtar M., Zhonglie An, Masaya Toda y Takahito Ono. "140 Mechanical properties of Carbon nanotubes-nickel composite thin films synthesized with high carbon nanotube content". Proceedings of Conference of Tohoku Branch 2016.51 (2016): 77–78. http://dx.doi.org/10.1299/jsmeth.2016.51.77.

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15

Harizanova, Sonya, Ivan Uzunov, Lyubomir Aleksandrov, Maria Shipochka, Ivanka Spassova y Mariya Kalapsazova. "The Beneficial Impact of Mineral Content in Spent-Coffee-Ground-Derived Hard Carbon on Sodium-Ion Storage". Materials 17, n.º 5 (22 de febrero de 2024): 1016. http://dx.doi.org/10.3390/ma17051016.

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The key technological implementation of sodium-ion batteries is converting biomass-derived hard carbons into effective anode materials. This becomes feasible if appropriate knowledge of the relations between the structure of carbonized biomass products, the mineral ash content in them, and Na storage properties is gained. In this study, we examine the simultaneous impact of the ash phase composition and carbon structure on the Na storage properties of hard carbons derived from spent coffee grounds (SCGs). The carbon structure is modified using the pre-carbonization of SCGs at 750 °C, followed by annealing at 1100 °C in an Ar atmosphere. Two variants of the pre-carbonization procedure are adopted: the pre-carbonization of SCGs in a fixed bed and CO2 flow. For the sake of comparison, the pre-carbonized products are chemically treated to remove the ash content. The Na storage performance of SCG-derived carbons is examined in model two and three Na-ion cells. It was found that ash-containing carbons outperformed the ash-free analogs with respect to cycling stability, Coulombic efficiency, and rate capability. The enhanced performance is explained in terms of the modification of the carbon surface by ash phases (mainly albite) and its interaction with the electrolyte, which is monitored by ex situ XPS.

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Soltani, Salman Masoudi y Sara Kazemi Yazdi. "Effect of Washing Solution on Surface Morphology and Ash Content of Porous Carbon". Applied Mechanics and Materials 368-370 (agosto de 2013): 726–29. http://dx.doi.org/10.4028/www.scientific.net/amm.368-370.726.

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This work highlights the effect of post-washing stage on the surface morphology and ash content of the final porous carbon. Three different acids were selected to post-wash charred carbon including nitric, sulfuric and phosphoric acids. Scanning electron microscopy (SEM) showed that the surface of the washed carbon was not much affected by acidic washing. Moreover, the amount of retained ash for the three acids (proximate analyses) showed that nitric acid-washed carbon could best remove surface ash from the charred carbon. Energy dispersive x-ray (EDX) also showed the presence of various heavy metals and heteroatoms on carbon surface. The results suggest that nitric acid would be best among the investigated acids to remove our charred carbons surface ash. This would enable the synthesized carbon to be used in more sensitive applications. However, the available ash still needs to be reduced if the carbon is to target highly sensitive applications such as drinking water treatments.

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17

Růžek, L., K. Voříšek, S. Strnadová, M. Nováková y W. Barabasz. "Microbial characteristics, carbon and nitrogen content in cambisols and luvisols". Plant, Soil and Environment 50, No. 5 (10 de diciembre de 2011): 196–204. http://dx.doi.org/10.17221/4022-pse.

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Tested soils (1991–2002) were defined by chemical, textural and microbial characteristics. From the tests which describe cambisols, the following parameters have to be stressed. The higher level of Corg (1.20–1.76%), which resulted in quite high microbial biomass carbon content (396–625 µg/g dry soil), high control respiration (0.45–0.80 mg CO2/h/100 g dry soil) and potential nitrification with (NH4)2SO4 (6.7–18.4 mg N-NO3/8 days/100 g dry soil). Studied luvisols reached typical levels: Corg (0.97–1.22%), CMB (398–503 µg/g dry soil), control respiration (0.46–0.57 mg CO2/h/100 g dry soil), potential nitrification with (NH4)2SO4 (3.2–9.9 mg N-NO3/8 days/100 g dry soil). Lower levels of organic carbon and a medium level of microbial biomass raised in higher ratio CMB/Corg (average 4.0%). Highly significant differences (p < 0.01) between cambisols and luvisols were determined for Corg, Nt, pH(KCl), CMB, CMB/Corg, CE, control respiration and potential nitrification, while the difference in potential ammonification with peptone was at level p < 0.05. With the exemption of ratio CMB/Corg all cambisol characteristics were higher than luvisol ones. Studied soils were evaluated by six biological criteria (CMB; ratios: CMB/Corg, CE/CMB, potential/control respiration, potential/control ammonification, potential/control nitrification). These criteria distinguished tested soils into three groups. The first one includes two localities in the mountain region (Červená Voda 809, 810; altitude 565–590 m) defined as stagnic cambisols with higher content of Corg (1.40, respective 1.76%) and simultaneously with the highest biomass of micro-organisms from all tested soils (CMB,625, respective 621 µg/g dry soil). It is not surprising that microbial activities (respiration, nitrification) at these localities were also high. The majority of the studied localities (one eutric cambisol and four luvisols) belongs to the medium group. The third group includes two localities (Neumětely – haplic luvisol, Čistá u Rakovníka – eutric cambisol) where biological criteria was mostly the worst. In the period 1993–2002 microbial biomass carbon was for both sites in the range of 357–458 µg/g dry soil which are not so bad values, but in comparison with localities in mountain wet region they are low. This status was issued in the lower ratio CMB/Corg (2.71–3.77%).

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Yu, Qiyun, Jiali Bai, Jiamei Huang, Muslum Demir, Bilge Nazli Altay, Xin Hu y Linlin Wang. "One-Pot Synthesis of N-Rich Porous Carbon for Efficient CO2 Adsorption Performance". Molecules 27, n.º 20 (12 de octubre de 2022): 6816. http://dx.doi.org/10.3390/molecules27206816.

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N-enriched porous carbons have played an important part in CO2 adsorption application thanks to their abundant porosity, high stability and tailorable surface properties while still suffering from a non-efficient and high-cost synthesis method. Herein, a series of N-doped porous carbons were prepared by a facile one-pot KOH activating strategy from commercial urea formaldehyde resin (UF). The textural properties and nitrogen content of the N-doped carbons were carefully controlled by the activating temperature and KOH/UF mass ratios. As-prepared N-doped carbons show 3D block-shaped morphology, the BET surface area of up to 980 m2/g together with a pore volume of 0.52 cm3/g and N content of 23.51 wt%. The optimal adsorbent (UFK-600-0.2) presents a high CO2 uptake capacity of 4.03 mmol/g at 0 °C and 1 bar. Moreover, as-prepared N-doped carbon adsorbents show moderate isosteric heat of adsorption (43–53 kJ/mol), acceptable ideal adsorption solution theory (IAST) selectivity of 35 and outstanding recycling performance. It has been pointed out that while the CO2 uptake was mostly dependent on the textural feature, the N content of carbon also plays a critical role to define the CO2 adsorption performance. The present study delivers favorable N-doped carbon for CO2 uptake and provides a promising strategy for the design and synthesis of the carbon adsorbents.

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Mavrov, V., I. Dobrevski, V. Peneva, S. Rashkov y N. Stathopoulos. "Treatment of Wastewater Containing Oil". Water Science and Technology 21, n.º 1 (1 de enero de 1989): 137–39. http://dx.doi.org/10.2166/wst.1989.0016.

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The possibilities for treatment of a wastewater containing 120 - 170 mg/l of oil, with a COD of 190 - 312 mg O2/l and a pH of 7 - 7.6, were studied. A treatment process consisting of coagulation and adsorption was investigated. The effectiveness of coagulation using aluminium sulphate, ferric chloride, and aluminium chloride, was examined, and for the adsorption process, three activated carbons (A, B, and C) were considered. Carbons A and B were new types of activated carbon based on different pyrolysed brown coals, and carbon C was a commercial activated carbon. It was established that the optimum results were achieved by coagulation with 140 mg/l aluminium chloride (Al2(OH)5Cl), which produced a treated effluent with an oil content of 11 - 12 mg/l, followed by adsorption using activated carbon A, which gave a treated effluent with an oil content below 2 mg/l. Carbon. A could treat up to 2200 bed volumes of water before regeneration of the activated carbon was necessary.

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20

Saha, Dipendu, Connelly P. Richards, Robert G. Haines, Nicholas D. D’Alessandro, Madeleine J. Kienbaum y Christian A. Griffaton. "Soft-Templating of Sulfur and Iron Dual-Doped Mesoporous Carbons: Lead Adsorption in Mixtures". Molecules 25, n.º 2 (18 de enero de 2020): 403. http://dx.doi.org/10.3390/molecules25020403.

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Lead pollution in drinking water is one of the most common problems worldwide. In this research, sulfur and iron dual-doped mesoporous carbons are synthesized by soft-templating with sulfur content 4.4–6.1 atom% and iron content 7.8–9 atom%. Sulfur functionalities of the carbons are expected to enhance the affinity of the carbon toward lead whereas iron content is expected to separate the carbon from water owing to its magnetic properties. All the carbons were characterized by pore textural properties, x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive x-ray (EDX). In order to study the Pb(II) removal efficiently of this carbon in competitive mode and to mimic the real-world use, one additional heavy-metal, including Cr(III), and four other commonly occurring metals—Na(I), K(I), Ca(II) and Fe (III)—are added with lead prior to adsorption experiments. It was observed that Pb(II) adsorption capacity of this carbon was not influenced by the presence of other metals. A highly elevated concentration of Na(I), K(I), Ca(II) and Fe(III) in the eluting solution compared to the initial dose suggested possible leaching of those metals from other salts as impurities, water source or even from the carbon itself, although the XPS analysis of the carbon confirmed negligible adsorption of those metals in carbon. From the equilibrium and kinetic data of adsorption, few parameters have been calculated, including distribution coefficient, diffusive time constant and pseudosecond order rate constant. The overall results suggest that these iron and sulfur dual-doped mesoporous carbons can serve as potential adsorbents for removal of lead from drinking water in the presence of other competing metals.

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21

Piedade, Ana P. y Liliana Cangueiro. "Influence of Carbyne Content on the Mechanical Performance of Nanothick Amorphous Carbon Coatings". Nanomaterials 10, n.º 4 (18 de abril de 2020): 780. http://dx.doi.org/10.3390/nano10040780.

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This study concerns the evaluation of the coefficient of friction, at different temperatures, of amorphous carbon thin films, deposited onto nanocrystalline sputtered copper coatings by clean-technology rf magnetron sputtering. The aim is to access the capacity of carbon thin films, with different contents of sp2 and sp1 bonds, to act as a solid lubricant for copper surfaces. Raman spectroscopy revealed that all the as-deposited coatings consist of amorphous carbon with low defect content and decreasing carbyne concentration with increasing thickness. The tribological tests at 25 °C and 200 °C revealed that, for the higher temperature, the 15 nm carbon coating present 0.001 friction coefficients at 2 N load. Overall, the study presents a one-step technology for the greener production of solid lubrication systems for micro- and nano-components, avoiding the environmental impact of lubricants.

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22

Volperts, Aleksandrs, Ance Plavniece, Kätlin Kaare, Galina Dobele, Aivars Zhurinsh y Ivar Kruusenberg. "Influence of Chemical Activation Temperatures on Nitrogen-Doped Carbon Material Structure, Pore Size Distribution and Oxygen Reduction Reaction Activity". Catalysts 11, n.º 12 (30 de noviembre de 2021): 1460. http://dx.doi.org/10.3390/catal11121460.

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The goal of this research was to synthesize activated nitrogen-doped nanocarbons with high specific surface area and adjustable pore size distribution using wood charcoal as a raw material. The resulting carbon materials were tested for possible application as oxygen reduction reaction catalysts in alkaline media. Activated carbons were obtained using a thermochemical activation method with NaOH. Nitrogen was introduced into activated carbons using dicyandiamide solution. It was demonstrated that the content of introduced nitrogen depends on oxygen content in the structure of the activated carbon. The oxygen reduction reaction activity of the activated and nitrogen-doped carbon material was comparable with a commercial 20% Pt/C catalyst. Electrocatalytic properties of the synthesized N-doped wood-derived carbon catalysts may be associated with the highly developed surface area, specific ratio of micro- and mesopores, as well as the high percentage of pyridinic nitrogen.

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23

Illescas, S., J. Fernández, J. Asensio, M. Sánchez-Soto y J. M. Guilemany. "Study of the mechanical properties of low carbon content HSLA steels". Revista de Metalurgia 45, n.º 6 (30 de diciembre de 2009): 424–31. http://dx.doi.org/10.3989/revmetalm.0902.

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24

Möhler, Ottmar, Claudia Linke, Harald Saathoff, Martin Schnaiter, Robert Wagner, Alexander Mangold, Martina Krämer y Ulrich Schurath. "Ice nucleation on flame soot aerosol of different organic carbon content". Meteorologische Zeitschrift 14, n.º 4 (15 de septiembre de 2005): 477–84. http://dx.doi.org/10.1127/0941-2948/2005/0055.

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25

Khasanova, G., A. Talipbek-kyzy, K. Kasymov, K. Tolokov y M. Tagaev. "Technology for Producing Composite Nano-structured Material Based on Natural Resources of the KR". Bulletin of Science and Practice 10, n.º 2 (15 de febrero de 2024): 369–78. http://dx.doi.org/10.33619/2414-2948/99/35.

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The history of development and current state of the coal sector of Kyrgyzstan is considered. The possibilities of obtaining carbon nanomaterials from carbons, such as carbon nanotubes, nanofibers, sphere particles, graphene, graphene oxide, graphene quantum dots and carbon dots, are analyzed. The optimal moisture content and density of low-dimensional carbon powder were determined. A special mold was used to produce a composite from carbon powders.

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26

Reljic, Snezana, Manuel Martinez-Escandell y Joaquin Silvestre-Albero. "Effect of Porosity and Surface Chemistry on CO2 and CH4 Adsorption in S-Doped and S-/O-co-Doped Porous Carbons". C 8, n.º 3 (15 de agosto de 2022): 41. http://dx.doi.org/10.3390/c8030041.

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The aim of this study was to determine the adsorption performance of a petroleum pitch-based activated carbon (PPAC1:3) before and after a post-treatment with H2S. In the first step, a microporous activated carbon (PPAC1:3) with a highly developed porous structure was produced through a chemical activation route with KOH. Afterward, the synthesized activated carbon was thermally treated yielding two different series of functionalized activated carbons: (i) a series of carbons were treated directly with H2S at elevated temperatures (600 °C and 800 °C), and (ii) a series of carbons were generated by combining an oxidation treatment with plasma followed by H2S treatment at elevated temperatures (600 °C and 800 °C). The chemical and structural characteristics of the S-doped and S-/O-co-doped porous carbons were investigated by means of different experimental techniques, such as XRD, RAMAN, FESEM, XPS, TPD, N2, and CO2 adsorption, and finally tested in CO2 and CH4 adsorption at atmospheric and high pressure. The functionalized porous carbons possessed specific surface areas of 2420–2690 m2/g, total pore volume of 1.05–1.18 cm3/g, and sulfur content up to 2.55 atom % (the sulfur content of the original carbon was 0.19%). After a careful analysis of the carbon dioxide and methane uptake at atmospheric (0.1 MPa) and high pressure (4 MPa), adsorption results confirm that the microporous structure is the main structural parameter defining the adsorption performance and, to a lower extent, the surface chemistry. Overall, a significant improvement in the total uptake can be appreciated after the H2S treatment.

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Cheng, Jun Hua y Di Jiang Wen. "Effects of Starting Carbon Sources on the Carbothermal Synthesis of SiC Powders". Advanced Materials Research 105-106 (abril de 2010): 754–57. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.754.

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Silicon carbide (SiC) powders have been prepared at 1200–1500°C by carbothermal reduction of two kind precursors of carbonl/silica mixtures: coked rice husk with high-carbon content, and gasified rice husk with low-carbon content mixed with carbon powders as an external carbon sources. The differences in nature of carbon matter in the external source and coked rice husk, and their effect on SiC synthesis have been studied by TG-DSC, TEM, XRD and laser diffraction technique. Experimental results show that the difference in nature of carbon source may affect the formation of SiC powders. The characteristics of the synthesized SiC particles strongly depend on the characteristics of the carbon sources.

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Trenggono, Mukti, Roy Andreas, Amron Amron, Rizqi Rizaldi Hidayat, Hendrayana Hendrayana, Rr Diah Febri Astuti y Cristiana Manullang. "An Assessment of Cilacap Coast's Total Carbonate Sediment Content". Jurnal Kelautan Tropis 24, n.º 1 (12 de diciembre de 2020): 15–24. http://dx.doi.org/10.14710/jkt.v24i1.8849.

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Sediments are particles derived from the dismantling of rocks from the land and pieces of shell and remains of marine organisms that contain organic matter, included carbonate sediment. The total carbonate sediment content was influenced by many factors, such as sediment grain type. This study aimed to determine the carbonate content in sediments and to determine their relationship to the sediment grain characteristic on the Cilacap coast. The sediment's carbonate content used the titration method, while the sediment grain test used a dry filter. Statistical analysis was used to determine the sediment grain characteristic (mean, sorting, skewness, and kurtosis). The results showed that sediments' total carbonate content had a range of 1.93% - 6.23%, with an average of 4.21%. Sediments are dominated by fine sand with very well sorted, very platykurtic, and very fine skewed characteristics. The relationship between sediment grain characteristics and total sediment carbonate content showed a good correlation due to the sorting factor. Other parameters such as mean size and skewness have been shown a low correlation, whereas kurtosis has a shallow relationship with carbonate content.

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29

Costa Ataides, Geilton, André Henrique Bueno Neves, Cássio Marques Moquedace dos Santos, Alaíde De Oliveira Carvalho, Kenia Michele de Quadros Tronco, Rogerio Gonçalves Teixeira, Vinícius Lima Pereira et al. "VARIAÇÃO ESPACIAL DOS ATRIBUTOS FÍSICOS E ESTOQUES DE CARBONO DO SOLO EM PLANTIO DE Schizolobium amazonicum NA AMAZÔNIA". Nativa 10, n.º 4 (14 de noviembre de 2022): 566–76. http://dx.doi.org/10.31413/nativa.v10i4.14540.

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Plantios de árvores proporcionam aumento dos estoques de carbono do solo, mas estudos envolvendo espécies nativas da Amazônia são incipientes. Objetivou-se avaliar a variação espacial dos atributos físicos e estoque de carbono orgânico no solo em plantio de paricá. Na área de estudo, coletaram-se amostras de solo nas profundidades de 0 a 20 cm e de 20 a 40 cm e os parâmetros analisados foram: textura do solo, macroporosidade, microporosidade, densidade aparente do solo, resistência mecânica do solo à penetração, teores e os estoques de carbono orgânico do solo. Interpolou-se os dados pelo inverso do quadrado da distância. A variação espacial dos atributos físicos do solo no plantio foi influenciada pela textura. Houve baixa amplitude da variação espacial dos teores e estoques de carbono orgânico do solo. O plantio de paricá apresentou eficiência na fixação de carbono no solo em profundidade. Palavras-chave: silvicultura; sequestro de carbono; física do solo; mudança climática. Spatial variation of physical attributes and soil carbon stocks in a Schizolobium amazonicum plantation in the amazon ABSTRACT: Tree plantations provide an increase in soil carbon stocks, but studies involving native Amazonian species are incipient. The objective was to evaluate the spatial variation of physical attributes and soil organic carbon stock in a paricá plantation. In the study area, soil samples were collected at depths of 0 to 20 cm and 20 to 40 cm and the parameters analyzed were: soil texture, macroporosity, microporosity, soil bulk density, mechanical soil resistance to penetration, and soil organic carbon content and stocks. The data were interpolated by the inverse of the square of the distance. The spatial variation of soil physical attributes at planting was influenced by texture. There was a low range of spatial variation in soil organic carbon content and stocks. Paricá planting was efficient in fixing soil carbon at depth. Keywords: silviculture; carbon sequestration; soil physics; climate change.

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Kristianingrum, Susila, S. Sulistyani y Annida Rifka Larastuti. "The Effectiveness of Active Carbon Adsorbent of Cassava Peel (Manihot Esculenta Cranzts) in Reduce Level of Chromium Metal in Tannery Liquid Waste". Indonesian Journal of Chemistry and Environment 5, n.º 2 (31 de diciembre de 2022): 58–67. http://dx.doi.org/10.21831/ijoce.v5i2.18813.

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This study aims to determine the characteristics, the effect of mass variation, the percentage of adsorption effectiveness of cassava peel activated carbon activated with 0.5 M HCl and activated with 0.5 M H2SO4 on the adsorption of Cr metal in leather tanning wastewater and its morphology. The subject of this research is the adsorbent of cassava peel before it is asctivated, activated by chloric acid 0,5 M, and activated by sulfuric acid 0,5 M. meanwhile the object of this research is the effectiviness of cassava peel adsorbeny in reduscing chromium metal content in tannery liquid waste. Cassava pell was carbonized at 500 oC for 1 hour. The cassava peel carbon was characterized according to SNI 06-3730-1995. The adsorption process is performed by batch method. Analysis was performed by Atomic Adsorption Spectrophotometer, PSA, and SEM-EDX. The result of the characterization of cassava peel carbon showed that the moisture content, ash content, adsorption capacity of I2 met SNI, meanwhile the carbon contenr and volatile matter conten did not met SNI. The adsorption efficiency of kromium metal is 95.97% for carbon before activated, 95.33% for carbon activated by chloroc acid, and 96.65% for carbon activated by sulfuric acid. The result of PSA size of cassava peel adsorbent before activated by chloric acid and sulfuric acid were 34.484 µm, 42.504 µm, and 37.059 µm respectively. Cassave peel adsorbent has a Langmuir adsorption type. The SEM-EDX result showed that the adsorbent from cassava peel had a dissimiliar pore shape

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Tawatbundit, Kanyanat y Sumrit Mopoung. "Activated Carbon Preparation from Sugarcane Leaf via a Low Temperature Hydrothermal Process for Aquaponic Treatment". Materials 15, n.º 6 (14 de marzo de 2022): 2133. http://dx.doi.org/10.3390/ma15062133.

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The effects of hydrothermal treatment, 0–5% KMnO4 content, and 300–400 °C pyrolysis temperature, were studied for activated carbon preparation from sugar cane leaves in comparison with non-hydrothermal treatment. The percent yield of activated carbon prepared by the hydrothermal method (20.33–36.23%) was higher than that prepared by the non-hydrothermal method (16.40–36.50%) and was higher with conditions employing the same content of KMnO4 (22.08–42.14%). The hydrothermal and pyrolysis temperatures have the effect of increasing the carbon content and aromatic nature of the synthesized activated carbons. In addition, KMnO4 utilization increased the O/C ratio and the content of C-O, Mn-OH, O-Mn-O, and Mn-O surface functional groups. KMnO4 also decreases zeta potential values throughout the pH range of 3 to 11 and the surface area and porosity of the pre-hydrothermal activated carbons. The use of the pre-hydrothermal activated carbon prepared with 3% KMnO4 and pyrolyzed at 350 °C as a filter in an aquaponic system could improve the quality of water with pH of 7.2–7.4, DO of 9.6–13.3 mg/L, and the turbidity of 2.35–2.90 NTU. It could also reduce the content of ammonia, nitrite, and phosphate with relative removal rates of 86.84%, 73.17%, and 53.33%, respectively. These results promoted a good growth of catfish and red oak lettuce.

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32

Abbas, Ammar Salih y Teeba Mohammed Darweesh. "Preparation and Characterization of Activated Carbon for Adsorption of Fluoroquinolones Antibiotics". Journal of Engineering 22, n.º 8 (1 de agosto de 2016): 140–57. http://dx.doi.org/10.31026/j.eng.2016.08.09.

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In this research, the preparation of a chemically activated carbon from date stones by using electric and microwave assisted K2CO3 activation was studied. The effect of radiation power, radiation time, and impregnation ratio on the yield and Iodine number on the activated carbons was investigated. The activated carbon characterizations were examined by its surface area, pore structure analysis, bulk density, moisture content, ash content, iodine number, FTIR, and scanning electron microscopy (SEM). The adsorption capacity was also studied by adsorption of fluoroquinolones antibiotics, CIP, NOR, and LEVO, by the prepared activated carbon.

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DENG Min, 邓敏, 叶满萍 YE Manping y 姜欣 JIANG Xin. "绿色荧光碳点检测有机溶剂中的水含量". ACTA PHOTONICA SINICA 52, n.º 12 (2023): 1216001. http://dx.doi.org/10.3788/gzxb20235212.1216001.

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34

Karthikeyan, S., P. Sivakumar y P. N. Palanisamy. "Novel Activated Carbons from Agricultural Wastes and their Characterization". E-Journal of Chemistry 5, n.º 2 (2008): 409–26. http://dx.doi.org/10.1155/2008/902073.

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Solid waste disposal has become a major problem in India, Either it has to be disposed safely or used for the recovery of valuable materials as agricultural wastes like turmeric waste,ferroniashell waste,jatropha curcusseed shell waste,delonixshell waste andipomea carniastem. Therefore these wastes have been explored for the preparation of activated carbon employing various techniques. Activated carbons prepared from agricultural solid wastes by chemical activation processes shows excellent improvement in the surface characteristics. Their characterization studies such as bulk density, moisture content, ash content, fixed carbon content, matter soluble in water, matter soluble in acid, pH, decolourising power, phenol number, ion exchange capacity, ion content and surface area have been carried out to assess the suitability of these carbons as absorbents in the water and wastewater. For anionic dyes (reactive, direct, acid) a close relationship between the surface area and surface chemical groups of the modified activated carbon and percentage of dye removal by adsorption can be observed. Cationic dyes large amount of surface chemical groups present in the sample (mainly carboxylic, anhydrides, lactones and phenolsetc.) are good anchoring sites for adsorption. The present study reveals the recovery of valuable adsorbents from readily and cheaply available agriculture wastes.

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35

Zhao, Chun Xia, Yun Xia Yang, Wen Chen, Paul A. Webley, Xiao Yu Li, Jin Qiao Cao y Jing Jing Du. "Characterization and Electrochemical Properties of Nitrogen-Doped Ordered Microporous Carbons Containing Well-Dispersed Platinum Nanoparticles". Advanced Materials Research 284-286 (julio de 2011): 875–79. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.875.

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Ordered high surface area microporous carbon molecular sieves containing well-dispersed platinum nanoparticles have been prepared by chemical vapor deposition method. Acetonitrile was employed as carbon and nitrogen precursors to yield N-doped carbon molecular sieves. N-doped carbons have an average nitrogen content of ~ 4.1 wt%. Electrochemical tests showed that the rectangular-shaped CVs of N-doped carbons could be well retained over a wide range of scan rates (5~100 mV/s), and the CV curves presented a steep current change at the switching potentials. N-doped carbons exhibited excellent performance as an electrochemical supercapacitor with a calculated specific capacitance of 168 F/g. Meanwhile, it was noticed that a reasonable Pt loading would help to improve the capacitance. It was proposed that the polarizability or surface state modification by nitrogen doping and regular interconnected porous structure might contribute to the improvement of N-doped carbons’ electrochemical properties.

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36

Llamas-Unzueta, Raúl, Luis A. Ramírez-Montoya, J. Angel Menéndez y Miguel A. Montes-Morán. "Customised Microporous Carbon 3D Structures with Good Mechanical Properties and High Nitrogen Content Obtained from Whey Powders". C 9, n.º 4 (24 de octubre de 2023): 100. http://dx.doi.org/10.3390/c9040100.

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Novel customised carbon monoliths with a high specific surface area were synthesised by carbonisation plus activation of dehydrated whey powders, a biomass byproduct of the dairy industry. The whey powders were casted directly by pouring them into a desired mould. After a pseudo-sintering process promoted by the self-reaction of the whey components (mostly lactose and whey proteins) at moderate temperatures (ca. 250 °C), 3D porous carbons were obtained. The process did not require any binder or external overpressure to prepare the 3D porous carbons. Upon thermal activation with CO2 or chemical activation with H3PO4 and KOH, the shape of the monolithic structure was preserved after the development of a microporous network (SBET up to 2400 m2/g). Both thermal and chemical activation had little effect on the macroporosity of the monoliths. Activation of these 3D carbons had to be performed with care to avoid heterogeneous skin/core activation and/or overactivation. Highly porous monoliths (SBET of 980 m2/g; open porosity of 70%) with outstanding compressive strength (10 MPa) could be obtained by thermal activation (CO2) of whey monoliths at 850 °C for 1.5 h. Additionally, the use of whey as a precursor provided the carbon monolith with a relatively high nitrogen content (ca. 3 wt.%).

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37

Kamedulski, Piotr, Malgorzata Skorupska, Izabela Koter, Maciej Lewandowski, Víctor Karim Abdelkader-Fernández y Jerzy P. Lukaszewicz. "Obtaining N-Enriched Mesoporous Carbon-Based by Means of Gamma Radiation". Nanomaterials 12, n.º 18 (12 de septiembre de 2022): 3156. http://dx.doi.org/10.3390/nano12183156.

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In this paper, we present the results of the gamma irradiation method to obtain N-doped mesoporous activated carbons. Nitrogen-enriched mesoporous carbons were prepared from three chosen commercial activated carbons such as Carbon Black OMCARB C-140, KETJENBLACK EC-600JD and PK 1-3 Norit. HRTEM, SEM, Raman spectra, elemental analysis, XPS studies and widely approved N2 adsorption–desorption measurements allowed us to evaluate the effectiveness of N atom insertion and its influence on the BET surface area and the pore structure of modified carbons. The obtained materials have an exceptionally high N content of up to 3.2 wt.%. Additionally, selected N-doped activated carbons were fully characterized to evaluate their applicability as carbon electrode materials with particular emphasis on Oxygen Reduction Reaction (ORR). The proposed method is a relatively facile, efficient and universal option that can be added to the already known methods of introducing heteroatoms to different carbons.

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38

Sebayang, Melya Dyanasari. "Battery on Carburization ST 37 Steel". Journal of Technomaterial Physics 3, n.º 2 (31 de agosto de 2021): 109–14. http://dx.doi.org/10.32734/jotp.v3i2.5810.

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A surface hardening process by adding carbon to its surface without changing the core properties of the material is called the carburization process. This process is carried out at the austenite temperature so that the carbon can diffuse into the phase. This process can only be done on low carbon steels with a content of below 0.25%. This research uses ST 37 steel which is a low content steel with a carbon content of 0.18%. This type of steel is surface hardened with a carburizing temperature of 850°C for a long lasting time of 1 hour, then it is carried out under moderate cooling with outside air media. This research produces a carburizing method with carbon battery media that easily breaks down into steel, which occurs in carbon batteries at temperatures below 723°C. And change its mechanical properties from the comparison of the initial mechanical properties of the specimen. Carburizing with battery rock media is more efficient at temperatures below 723°C. Because of at temperatures below austenite or below the carburizing temperature of carbon from the batteries, it can absorb the surface of the steel even though the amount is still very small. Because the temperature is below the austenite temperature, the absorbed carbons cannot diffuse as happened in the carburization process, but the absorbed carbons can bind the grain boundaries so that they change their hardness by 4%. The microstructure in the research that occurs in this process has nothing to change its phase because the temperature does not reach the austenite temperature.

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39

Frilund, Christian, Ilkka Hiltunen y Pekka Simell. "Activated Carbons for Syngas Desulfurization: Evaluating Approaches for Enhancing Low-Temperature H2S Oxidation Rate". ChemEngineering 5, n.º 2 (11 de mayo de 2021): 23. http://dx.doi.org/10.3390/chemengineering5020023.

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Its relatively low cost and high surface area makes activated carbon an ideal adsorbent candidate for H2S removal. However, physical adsorption of H2S is not very effective; therefore, methods to facilitate reactive H2S oxidation on carbons are of interest. The performance of H2S removal of non-impregnated, impregnated, and doped activated carbon in low-temperature syngas was evaluated in fixed-bed breakthrough tests. The importance of oxygen content and relative humidity was established for reactive H2S removal. Impregnates especially improved the adsorption rate compared to non-impregnated carbons. Non-impregnated carbons could however retain a high capture capacity with sufficient contact time. In a relative performance test, the best performance was achieved by doped activated carbon, 320 mg g−1. Ammonia in syngas was found to significantly improve the adsorption rate of non-impregnated activated carbon. A small quantity of ammonia was consumed by the carbon bed, suggesting that ammonia is a reactant. Finally, to validate ammonia-enhanced desulfurization, bench-scale experiments were performed in biomass-based gasification syngas. The results show that when the ammonia concentration in syngas was in the tens of ppm range, 40–160 ppm H2S oxidation proceeded rapidly. Ammonia-enhanced oxidation allows utilization of cheaper non-impregnated activated carbons by in situ improvement of the adsorption kinetics. Ammonia enhancement is therefore established as a viable method for achieving high-capacity H2S removal with unmodified activated carbons.

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40

Andreas, Roy, Uyi Sulaeman y Tien Setyaningtyas. "PEMANFAATAN KARBON SABUT KELAPA TERIMPREGNASI UNTUK MENGURANGI TEMBAGA(II) DALAM MEDIUM AIR". Molekul 3, n.º 2 (1 de noviembre de 2008): 91. http://dx.doi.org/10.20884/1.jm.2008.3.2.53.

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This research is conducted to produce carbons from coconut fibre which approach to activated carbon clause continue with carbon surface modification and the adsorption examination to Cu(II) ions. The research consist of several phase. Carbon making of coconut fibre conducted by carbonization processes at 320-400oC with temperature interval 20oC. Carbon yielded in characterized moisture content, ash content and its adsoprtion to iodium. The carbon surface modification conducted by loaded 2-mercaptobenzotiazol (MBT) on carbon. The adsorpsibility of carbon-MBT tested by influence of contact time, pH, and the isoterm adsorption pattern. The result of the study showed carbonization of coconut fibre which approach the requirement of SII No.0258-89 gained at temperature 320oC. In the present study equilibrium time of 10 minute and pH was found to be optimum for both adsorbent. While type of isothermal adsorption from carban and carbon-MBT adsorbent followed the Langmuir adsorption pattern.

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41

Wang, Zi Qiang, Li Xian Sun, Fen Xu y Xiao Jun Peng. "The Synthesis of Nitrogen-Doped Mesoporous Carbon Spheres for Hydrogen Storage". Materials Science Forum 852 (abril de 2016): 864–69. http://dx.doi.org/10.4028/www.scientific.net/msf.852.864.

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The nitrogen-doped mesoporous carbon spheres have been synthesized via soft-template and hydrothermal synthetic strategies using phenol/formaldehyde resins as carbon sources and melamine as a nitrogen source. The obtained carbon spheres exhibit a spherical morphology with a size range of 3-5 μm, which possess the narrow microporosity (ca. 1.2 nm) and mesoporosity (ca. 4 nm), large surface area (560-1200 m2 g-1) and high nitrogen contents (up to 15.7 wt%). Due to the well-developed porous structure and high nitrogen content, the carbon spheres show high performance for hydrogen storage, and the hydrogen adsorption capacities are in the range of 140-185 cm3 g-1, which is better than that of most activated carbons. The incorporation of nitrogen into carbons is favored for hydrogen uptake in low pressure.

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42

Nishida, Shin-ichi, Nobusuke Hattori y Tomoyoshi Kawano. "OS11W0284 Effect of Sn content on fatigue properties of extra-low carbon steels". Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2003.2 (2003): _OS11W0284. http://dx.doi.org/10.1299/jsmeatem.2003.2._os11w0284.

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43

Vasilkovskyi, Vsevolod, Serhii Minieiev y Nadiia Kaluhina. "Bonding energy and methane amount at the open surface of metamorphic coal". E3S Web of Conferences 109 (2019): 00108. http://dx.doi.org/10.1051/e3sconf/201910900108.

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Objective of the studies is to measure and determine regularities of changes in adsorption and methane energy bond with the open surface of mineral carbons within metamorphism series. Donbas mineral carbons have been used as the samples. Volumetric method has been applied in the range of room temperatures and pressures of free methane phase (i.e. 0.015 to 3.5 MPa) to measure methane amount at the open surface of the mineral carbons. Depending upon changes in carbon content, adsorption behaviour is close to parabolic one: adsorption is maximal on the peripheries of metamorphic series, and minimal within its central part. For the first time, methane energy bond with the open surface of mineral carbons has been determined. In the context of the metamorphic series, bonding energy varies from 2 to 10 kJ/mol. Direct linear dependence of adsorption from pressure takes place for coal where carbon content is less than 76 %. It is the result of effect of large area of open surface of low-metamorphized coal. Inversely, nonlinear dependence is observed as for anthracite. The authors connect the fact with filling of all spaces at the open surface when gas phase pressure is 0.1 MPa.

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44

Gomis-Berenguer, Alicia, Irma Eliani, Vânia F. Lourenço, Rocio J. Carmona, Leticia F. Velasco y Conchi O. Ania. "Insights on the Use of Carbon Additives as Promoters of the Visible-Light Photocatalytic Activity of Bi2WO6". Materials 12, n.º 3 (26 de enero de 2019): 385. http://dx.doi.org/10.3390/ma12030385.

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We have explored the impact of the incorporation of various amounts of carbons from varied physicochemical features as additives to Bi2WO6 for the photocatalytic degradation of a dye using simulated solar light. Data has revealed that the composition and acidic character of the carbon additive are important parameters in the performance of the Bi2WO6/carbon catalysts. The presence of a carbon additive improved the conversion of the dye, evidencing the occurrence of charge transfer reactions that involve radical mediated reactions. The catalysts prepared with 2 and 5 wt.% of carbon additive outperformed the bare semiconductor, despite the shielding effect of the carbon matrix. The acidic nature of the Bi2WO6/carbon catalysts governs the degradation pathway (due to the preferential adsorption of the dye), that proceeds via the deethylation of the auxochrome groups of the dye at short irradiation times, followed by the cleavage of the chromophore at long irradiation times. Regarding the characteristics of the carbons, the photocatalytic degradation rate is accelerated by carbons of acidic character and high oxygen content, whereas the porosity seems to play a minor role. The presence of the carbon additives also affects the toxicity of the treated solutions, rendering lower values after shorter irradiation periods.

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45

Zhou, Jin y Shu Ping Zhuo. "Capacitive Performance of Ordered Mesoporous Carbons in Ionic Liquids". Advanced Materials Research 284-286 (julio de 2011): 2086–89. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.2086.

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Ordered mesoporous carbons (BOMC) were prepared by doping boric acid using a hard-templating method, while a CMK-3 carbon (OMC) was also prepared for comparison. The capacitive performance of these two carbons was investigated in ionic liquid of EMImBF4 and EMImTSFI. As demonstrated by the structure analysis, BOMC possesses almost same surface area and pore size as OMC, while the former carbon possesses higher content of oxygen-containing groups. In ionic liquid electrolyte, the carbons mainly show typical electric double layer capacitance, and the capacitance retention ratio and ion diffusion of electrolyte is determined to the surface chemical property. BOMC present visible pseudo-capacitance due to the oxygenated groups in hydrophilic EMImBF4, while no visible pseudo-capacitive behavior was observed in hydrophobic EMImTSFI.

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46

Palanivel, C., L. D. Prabhakar y M. Emayavaramban. "Characterization of Palm Nut Shell Carbon and Treated Flyash Residue for Adsorption of Coloring Matter from Aqueous Systems". International Letters of Chemistry, Physics and Astronomy 7 (septiembre de 2013): 72–79. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.7.72.

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The Palm Nut Shell Carbon (PNSC) and Treated Flyash Residue (TFR) has prepared by sulphuric acid process and characterized.The characterization studies includes determination of moisture, bulk density, pH, carbon soluble in water and acid, decolourising power, iron content, phenol number and surface area parameters.The characteristics of these carbons were compared with that of high cost activated charcoal carbon (ACC).The PNSC and TFR were used for adsorption of colouring matter from the textile dyeing industrial effluents.

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47

Palanivel, C., L. D. Prabhakar y M. Emayavaramban. "Characterization of Palm Nut Shell Carbon and Treated Flyash Residue for Adsorption of Coloring Matter from Aqueous Systems". International Letters of Chemistry, Physics and Astronomy 7 (31 de enero de 2013): 72–79. http://dx.doi.org/10.56431/p-4jslnb.

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The Palm Nut Shell Carbon (PNSC) and Treated Flyash Residue (TFR) has prepared by sulphuric acid process and characterized.The characterization studies includes determination of moisture, bulk density, pH, carbon soluble in water and acid, decolourising power, iron content, phenol number and surface area parameters.The characteristics of these carbons were compared with that of high cost activated charcoal carbon (ACC).The PNSC and TFR were used for adsorption of colouring matter from the textile dyeing industrial effluents.

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Gutierrez, Liliana Giraldo y Juan Carlos Moreno-Piraján. "Immersion enthalpy variation of surface-modified mineral activated carbon in lead (II) aqueous solution adsorption: the relation between immersion enthalpy and adsorption capacity". Ecletica Quimica 31, n.º 4 (30 de diciembre de 2006): 15–21. http://dx.doi.org/10.26850/1678-4618eqj.v31.4.2006.p15-21.

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An activated carbon was obtained by chemical activation with phosphoric acid, CM, froma mineral carbon. Afterwards, the carbon was modified with 2 and 5 molL -1 , CMox2 and CMox5 nitricacid solutions to increase the surface acid group contents. Immersion enthalpy at pH 4 values and Pb 2+adsorption isotherms were determined by immersing activated carbons in aqueous solution. Thesurface area values of the adsorbents and total pore volume were approximately 560 m 2 .g -1 and 0.36cm 3 g -1 , respectively. As regards chemical characteristics, activated carbons had higher acid sitescontent, 0.92-2.42 meq g -1 , than basic sites, 0.63-0.12 meq g -1 . pH values were between 7.4 and 4.5 atthe point of zero charge, pH PZC. The adsorbed quantity of Pb 2+ and the immersion enthalpy in solutionof different pH values for CM activated carbon showed that the values are the highest for pH 4, 15.7mgg -1 and 27.6 Jg -1 respectively. Pb 2+ adsorption isotherms and immersion enthalpy were determinedfor modified activated carbons and the highest values were obtained for the activated carbon thatshowed the highest content of total acid sites on the surface.

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49

Ahmad Zaini, Muhammad Abbas y Abdul Haris Ali. "Adsorptive characteristics and microwave dielectric properties of oil palm empty fruit bunch-based activated carbons for dye removal". Malaysian Journal of Fundamental and Applied Sciences 14, n.º 2 (3 de junio de 2018): 241–45. http://dx.doi.org/10.11113/mjfas.v14n2.1083.

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The present study was aimed to evaluate the adsorptive characteristics and microwave dielectric properties of activated carbons derived from oil palm empty fruit bunch (EFB) prepared by microwave-assisted potassium hydroxide activation at 300 W and 800 W for 5 min. The resultant products were characterized for dielectric properties, BET specific surface area, surface functional groups and methylene blue adsorption. Results show that the microwave-assisted activation yields activated carbons with surface area of 695 m2/g and 1339 m2/g for heating rates (microwave irradiation power) of 300 W and 800 W, respectively and both exhibit more than 95% removal of methylene blue at concentrations higher than 100 mg/L. The dielectric properties revealed a better propensity of activated carbons towards microwave heating especially at a higher heating rate due to high surface area, and possibly high moisture content and carbon content. A greater heating rate or microwave power could turn EFB into activated carbon with a higher surface area and excellent adsorptive properties for pollution abatement.

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50

Montoya-Suarez, Sergio, Fredy Colpas-Castillo, Edgardo Meza-Fuentes, Johana Rodríguez-Ruiz y Roberto Fernandez-Maestre. "Activated carbons from waste of oil-palm kernel shells, sawdust and tannery leather scraps and application to chromium(VI), phenol, and methylene blue dye adsorption". Water Science and Technology 73, n.º 1 (7 de septiembre de 2015): 21–27. http://dx.doi.org/10.2166/wst.2015.293.

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Phenol, chromium, and dyes are continuously dumped into water bodies; the adsorption of these contaminants on activated carbon is a low-cost alternative for water remediation. We synthesized activated carbons from industrial waste of palm oil seed husks (kernel shells), sawdust, and tannery leather scraps. These materials were heated for 24 h at 600, 700 or 800°C, activated at 900°C with CO2 and characterized by proximate analysis and measurement of specific surface area (Brunauer–Emmett–Teller (BET) and Langmuir), and microporosity (t-plot). Isotherms showed micropores and mesopores in activated carbons. Palm seed activated carbon showed the highest fixed carbon content (96%), and Langmuir specific surface areas up to 1,268 m2/g, higher than those from sawdust (581 m2/g) and leather scraps (400 m2/g). The carbons were applied to adsorption of Cr(VI), phenol, and methylene blue dye from aqueous solutions. Phenol adsorption on activated carbons was 78–82 mg/g; on palm seed activated carbons, Cr(VI) adsorption at pH 7 was 0.35–0.37 mg/g, and methylene blue adsorption was 40–110 mg/g, higher than those from sawdust and leather scraps. Activated carbons from palm seed are promising materials to remove contaminants from the environment and represent an alternative application for vegetal wastes instead of dumping into landfills.

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