Search

This study synthesized the activated carbon as material support for platinum catalysts in fuel cells application. The pyrolytic carbon black from the waste tyre was activated through physical activation using oxygen gas in a vertical bed column. The activation influencing factors are then examined, which include the activation temperature, the activation time, and the composition of oxidant oxygen gas in the activation. The results showed that the optimum operating conditions for the carbon black activation into its corresponding activated carbon are activation temperature at 300℃, activation time for 1 hour with pure oxidant oxygen gas. The resulting activated carbon was also successfully tested as a potential platinum-fuel cell catalyst support (Pt/AC) in the methanol oxidation reaction (MOR) in Direct Methanol Fuel Cell (DMFC) application, as indicated from the electrochemical testing, i.e. the cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurement. The CV measurement showed that this Pt/AC catalyst generates the region of hydrogen adsorption/desorption (Hads/des), the double-layer charging and discharging, and the CO oxidation-reduction. In addition, during the LSV measurement, this Pt/AC catalyst showed the reactivity towards MOR with its current density of 0.0005 A.cm-2 at 0.6 V.

This study presents the effects of different activation methods to produce activated carbon from the hydrolysis lignin. Pretreatment of the feedstock with common mineral acids (HCL, HNO₃, and H₃PO₄), different steam rates for physical activation, and different chemical activating agents (ZnCl₂, Na₂CO₃, and KOH) for chemical activation were investigated. The pretreated biomass was carbonized and activated in one-stage process and the surface characteristics, such as total pore volume, pore size distribution and specific surface area, were investigated. The results showed that the activated carbon surface properties were not greatly affected by acid pretreatment. Brunauer-Emmett-Teller (BET) surface areas as high as 616 m²/g could be achieved with physical activation and 2054 m²/g with chemical activation. Different steam rates in the selected interval (0.5–2 cm³/min) did not change the pore size distribution but had small positive effect on the specific surface area, while chemical activation with ZnCl₂ increased the mesoporosity, and activation with KOH increased the microporosity and oxygen groups in the form of ether and alcohol bonds.

This study synthesized the activated carbon as material support for platinum catalysts in fuel cells application. The pyrolytic carbon black from the waste tyre was activated through physical activation using oxygen gas in a vertical bed column. The activation influencing factors are then examined, which include the activation temperature, the activation time, and the composition of oxidant oxygen gas in the activation. The results showed that the optimum operating conditions for the carbon black activation into its corresponding activated carbon are activation temperature at 300℃, activation time for 1 hour with pure oxidant oxygen gas. The resulting activated carbon was also successfully tested as a potential platinum-fuel cell catalyst support (Pt/AC) in the methanol oxidation reaction (MOR) in Direct Methanol Fuel Cell (DMFC) application, as indicated from the electrochemical testing, i.e. the cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurement. The CV measurement showed that this Pt/AC catalyst generates the region of hydrogen adsorption/desorption (Hads/des), the double-layer charging and discharging, and the CO oxidation-reduction. In addition, during the LSV measurement, this Pt/AC catalyst showed the reactivity towards MOR with its current density of 0.0005 A.cm-2 at 0.6 V.

Heavy metal such as lead has increase in the natural environment especially in the aqueous solution. Remediation method of adsorption offer a treatment for removing heavy metal in river. This experiment is to analyse and compare eggshell adsorbent of activated carbon in Panchor’s river through its efficiency in removing heavy metal of Lead (II). Eggshell is designed as an activated carbon through physical and chemical activation in treating the water by undergoing adsorption process of few laboratory test. The efficiency of eggshell chemical activated carbon is high as the percentages removal of Pb is 48.21% compare to physical activated carbon with 32.14%. However, this study showed that both eggshell activated carbon is an effective adsorbent in removing Pb from aqueous solution of natural environment

Worldwide, tons of lignin is produced annually in pulping plants and it is mainly considered as a waste material. Usually lignin is burned to produce energy for the pulping reactors. The production of value-added materials from renewable materials like lignin, has proved to be challenging. In this study, the effects of addition of three different types of lignin in the production of tannin/furanic foams is investigated. The foams were matured, first at 373 K and finally carbonized at 1073 K and the properties of them including mechanical strength, specific surface area and pore development are investigated before and after thermal treatment. According to the results, higher mechanical strength is obtained if samples are carbonized at 1073K compared to matured ones at 373K. Up to 10 times stronger materials are achieved this way, which makes them promising as insulating or constructive materials. With physical activation, it is possible to obtain specific surface areas and pore volumes close to 1200 m2/g and 0,55 cm3/g respectively. Mainly micropores are developed during the steam activation which makes these foams more suitable and selective to be used as catalyst support materials in the catalytic conversion of small molecules or in adsorption or gas storage application.

The main aim of the present study is to provide a comprehensive assessment of the effects of process activation conditions on the textural properties of the resulting activated carbons, which were produced from wheat straw-derived biochar through chemical activation (with K2CO3 at different pressures and mass impregnation ratios) and physical activation (with CO2 at different temperatures and pressures). For chemically activated biochars, it was found that specific surface area and pore size distribution were both only positively affected by increasing the carbonate loading. However, physically activated biochars produced at the highest pressure and lowest temperature (1.0 MPa and 700 °C) had the highest surface areas and widest pore size distributions. The materials with the most appropriate textural properties were then tested as catalysts for steam and dry reforming of the aqueous phase of pyrolysis oil. The best catalytic performance (a total gas yield of 74% and a selectivity toward H2 of almost 40%) was observed for a physically activated biochar. This good performance was ascribed to the high availability of K0 on the catalyst surface, which could effectively promote the reactions involved in the upgrading process.

Biomass is the most abundant renewable material present on Earth and has been widely used e.g. in energy production. Recently, new applications for biomass utilization have been developed, e.g. the use of biomass as a raw material for synthesizing new chemicals. This research aimed to produce activated carbon (AC) from waste wood-based materials and peat through carbonization followed by physical or chemical activation. Physical steam activation and chemical activation generate the porosity in AC after the carbonization. The desired properties of AC (porosity, pore size distribution, surface functionality) are dependent on the application in which AC is used. The first part of the research focused on setting up the carbonization and activation device. The most important variables affecting carbonization and activation and the AC properties were studied. The process parameters were optimized through the design of experiments (DOE). The results showed that in the physical activation, the most important variables affecting the characteristics of AC are the holding time, temperature, and the steam feed. Consequently, a model for tailoring the microporosity or mesoporosity of AC and maximizing the yield is proposed. The second part of the research focused on chemical activation using zinc chloride. The aim was to study the effect of activation variables on the yield and properties of AC. Finally, the use of AC as an adsorbent was studied. Especially, the applicability of birch sawdust based activated carbon on the removal of dyes, zinc metal, nitrate, phosphate, and sulfate ions was evaluated. Based on the results, a difference was shown between one and two step process for carbonization and activation, and a single-step process was suggested to maximize the quality of AC., Tiivistelmä Biomassa on maapallon eniten saatavilla olevaa uusiutuvaa materiaalia, jota on hyödynnetty jo pitkään mm. energiantuotannossa. Viime aikoina uusia biomassan käyttökohteita on kehitetty laajalti, kuten esimerkiksi uusien kemikaalien valmistukseen. Tässä tutkimuksessa puupohjaista jätebiomassaa ja turvetta hyödynnetään fysikaalisesti ja kemiallisesti aktivoidun aktiivihiilen valmistuksessa. Fysikaalinen höyryaktivointi ja kemiallinen aktivointi lisäävät aktiivihiilen huokoisuutta hiilestyksen jälkeen. Aktiivihiilen halutut ominaisuudet (huokoskokojakauma, pinnan toiminnalliset ryhmät) määräytyvät käyttökohteen mukaan. Tutkimuksen ensimmäisessä vaiheessa keskityttiin hidas pyrolyysilaitteiston ja aktivointilaitteiston rakentamiseen sekä hiilestyksen ja aktivoinnin kannalta keskeisimpien muuttujien tutkimiseen. Prosessimuuttujien vaikutusten tarkastelussa ja optimoinnissa hyödynnettiin koesuunnitteluohjelmaa. Tulosten perusteella todettiin, että fysikaalisessa aktivoinnissa olennaisimmat muuttujat olivat lämpötila, pitoaika sekä höyrysyöttö. Tämän pohjalta esitettiin malli aktiivihiilen mikro- ja mesohuokoisuuden muokkaamiseksi ja saannon maksimoimiseksi. Tutkimuksen toisessa vaiheessa tutkittiin kemiallista aktivointia hyödyntämällä sinkkikloridia aktivointikemikaalina. Tavoitteena oli selvittää eri aktivointimuuttujien vaikutusta saantoon ja aktiivihiilen laatuun. Tutkimuksen viimeisessä vaiheessa tutkittiin valmistettujen aktiivihiilien käyttöä adsorbenttina. Erityisesti tutkittiin koivupurusta valmistetun aktiivihiilen soveltuvuutta väriaineiden, metallien ja anionien sidontaan. Tutkimuksen keskeisenä tuloksena voitiin osoittaa merkittävä ero yksi- ja kaksivaiheisen hiilestyksen ja aktivoinnin välillä, ja ehdotettiin yksivaiheista prosessia hiililaadun optimoimiseksi., Sommario La biomassa è il materiale rinnovabile più abbondante presente sulla Terra ed è stata intensamente usata e.g. nella produzione di energia. Recentemente sono state sviluppate nuove applicazioni per la biomassa, ad esempio come materiale di base per sintetizzare nuovi prodotti chimici. Lo scopo di questa ricerca è produrre carbone attivo (CA) attraverso attivazione fisica e chimica da materiali legnosi di scarto come segatura, cippato e torba. L’attivazione fisica e l’attivazione chimica, creano la porosità nel CA dopo la carbonizzazione. Il prodotto finale può essere usato in differenti applicazioni in base a diversi fattori tra cui la distribuzione della porosità e la tipologia dei gruppi funzionali presenti sulla superficie. La prima fase della ricerca è stata dedicata alla progettazione e installazione dell’hardware necessario per l’attivazione e nell’individuazione dei parametri di processo più importanti. I parametri di processo sono stati ottimizzati attraverso il design of experiments (DOE) e sono state considerate le differenti variabili che interagiscono nella formazione del CA. I risultati hanno mostrato che i parametri di processo più importanti che influiscono sulle caratteristiche del CA sono il tempo, la temperatura di attivazione e la quantità di vapore iniettato nel reattore. È stato proposto un modello per progettare CA microporoso o mesoporoso con massa finale massimizzata. La seconda parte della ricerca è stata incentrata sull’attivazione chimica con cloruro di zinco. Lo scopo é stato studiare l’effetto delle variabili di attivazione su massa finale e proprietà del carbone attivo. Infine, è stata studiato il CA come adsorbente. In particolare è stata considerata l’applicabilità del CA da segatura di betulla per la rimozione di coloranti, zinco metallico, ioni di nitrato, fosfato e solfato. In base a questi risultati, una differenza é stata evidenziata tra il processo di carbonizzazione e attivazione a uno o due stadi, ed il processo a sing

Recently, bio-based carbon foams have gained much interest in many chemical industry fields because of their unique structure and properties. This study provides new information on the effects of catalytic metals (iron, nickel, and copper) on the foaming process. Specifically, the effects of these catalysts on the density, foam growth, and cell size and then further on the pore size distribution and specific surface areas after the physical activation are considered. Furthermore, some of the activated sugar foams were used in adsorption tests using methylene blue as adsorbent. Results showed that the highest effect on foam density was obtained using the iron catalyst in the foaming process. In addition, increasing the iron amount, the development of micro-pores decreased from 95.2 to 60.3% after cabonization and activation of the foams. Nickel and iron had the highest and lowest effect on foam rise at 1375 and 500%, respectively. Interestingly, when the nickel catalyst was used, cell sizes and surface areas two times larger than those when the foams were prepared with the iron and copper catalysts was obtained. The specific surface area of activated sugar-based carbon foams changed significantly with the increased copper amount inside the foaming solution in compared with iron or nickel catalyst. Methylene blue adsorption capacity of additional series of activated sugar foams decreased from 28 to 9% when meso-pore amount decreased.

In this study, tannin-furanic-based foams enforced with H3BO3 and ZnCl2 are investigated, as well as their properties such as mechanical strength, specific surface area, and pore size distribution. From an industrial point of view, the aforementioned properties of these foams play a key role when used as catalyst, adsorbent, or gas storing materials. Therefore, this study aims to prove that such enforced tannin-furanic foams are promising materials for these types of applications. According to the results, materials that are up to five times stronger can be achieved by carbonizing the foams in comparison to maturing them. With physical activation, it was possible to obtain a specific surface area as high as 845 m2/g with a pore volume of up to 0.35 cm3/g. Chemical activation, using ZnCl2as the activating agent, produced a specific surface area and pore volume of 737 m2/g and 0.31 cm3/g. However,the pore sizes were mostly microporous, independently of activation procedure used.

Activated carbons (ACs) can be produced from biomass in a thermal process either in a direct carbonization-activation process or by first carbonizing the biomass and later activating the bio-chars into activated carbons. The properties of the ACs are dependent on the type of process used for production. In this study, the properties of activated carbons produced in one-stage and two-stage processes are considered. Activated carbons were produced by physical activation of two types of starting materials: bio chars produced from spruce and birch chips in a commercial carbonization plant and from the corresponding raw chips. The activated carbons produced were characterized regarding specific surfaces, pore volumes, and pore size distributions. The un-activated bio chars had varying surface areas, 190 and 140 m² g⁻¹ for birch and spruce, respectively, and pore volumes of 0.092 and 0.067 cm³ g⁻¹, respectively. On the other hand, 530–617 and 647–679 m² g⁻¹ for activated bio chars from birch and spruce, respectively, and pore volumes 0.366–0.509 and 0.545–0.555 cm³ g⁻¹, respectively, were obtained. According to the results obtained, two slightly different types of activated carbons are produced depending on whether a one-stage or a two-stage carbonization and activation process is used. The ACs produced in the one-stage process had higher specific surface areas (SSA), according to the BET-model (Brunauer–Emmett–Teller), compared to the ones produced in a two-stage process (761–940 m² g⁻¹ vs. 540–650 m² g⁻¹, respectively). In addition, total pore volumes were higher in ACs from the one-stage process, but development of micro-pores was greater compared to those of the two-stage process. This indicates that the process can have an influence on the ACs’ porosity. There was no significant difference in total carbon content in general between the one-stage and two-stage processes for spruce and birch samples, but some differences were seen between the starting materials. Es

Activated carbons (ACs) can be produced from biomass in a thermal process either in a direct carbonization-activation process or by first carbonizing the biomass and later activating the bio-chars into activated carbons. The properties of the ACs are dependent on the type of process used for production. In this study, the properties of activated carbons produced in one-stage and two-stage processes are considered. Activated carbons were produced by physical activation of two types of starting materials: bio chars produced from spruce and birch chips in a commercial carbonization plant and from the corresponding raw chips. The activated carbons produced were characterized regarding specific surfaces, pore volumes, and pore size distributions. The un-activated bio chars had varying surface areas, 190 and 140 m² g⁻¹ for birch and spruce, respectively, and pore volumes of 0.092 and 0.067 cm³ g⁻¹, respectively. On the other hand, 530–617 and 647–679 m² g⁻¹ for activated bio chars from birch and spruce, respectively, and pore volumes 0.366–0.509 and 0.545–0.555 cm³ g⁻¹, respectively, were obtained. According to the results obtained, two slightly different types of activated carbons are produced depending on whether a one-stage or a two-stage carbonization and activation process is used. The ACs produced in the one-stage process had higher specific surface areas (SSA), according to the BET-model (Brunauer–Emmett–Teller), compared to the ones produced in a two-stage process (761–940 m² g⁻¹ vs. 540–650 m² g⁻¹, respectively). In addition, total pore volumes were higher in ACs from the one-stage process, but development of micro-pores was greater compared to those of the two-stage process. This indicates that the process can have an influence on the ACs’ porosity. There was no significant difference in total carbon content in general between the one-stage and two-stage processes for spruce and birch samples, but some differences were seen between the starting materials. Es

Activated carbon is one of the most widely applied adsorbent. As a porous carbon, it is used for the purification of both gaseous and liquid emissions. Activated carbon is prepared from fossil resources, such as coal, or from biomass through (hydro)thermal processing followed by chemical and/or physical activation. Further, some biomass thermal treatment processes, such as biomass gasification, produce carbon residues that can be modified to activated carbon with physical or chemical activation methods. The desired properties of activated carbon, i.e. high specific surface area and porosity, high carbon content and excellent sorption capacity, can be modified and optimized during thermochemical treatment and activation. Those properties, which are shortly considered, are important in different applications for activated carbon.

Coconut shell-based activated carbons intended for CH4 storage were prepared by chemical activation with H3PO4 or ZnCl2 and/or physical activation with CO2. Efforts were focused to establish relationships among the activation procedure, the textural and physical-chemical properties of the resulting materials and their volumetric CH4 uptake. The best results were achieved by using the combination of a relatively soft chemical activation with H3PO4 or ZnCl2, just the sufficient to minimize the presence of macropores originated from the botanical structure of the precursor, followed by physical activation with CO2 to develop a narrow pore size distribution mainly located around the optimum pore diameter/width for CH4 storage. This combined methodology permitted to obtain excess volumetric CH4 adsorption capacities as high as 94, 148 and 145 V/V for granular, powdered/compressed and monolithic carbons, respectively. The corresponding total CH4 storing capacities were estimated to be 102, 165 and 163 V/V. It is worthy to highlight that the precursor was a low cost and abundant agricultural by-product, which is very important for large-scale applications such as gas transportation and gas storage in vehicular fuel tanks.

Coconut shell-based activated carbons intended for CH4 storage were prepared by chemical activation with H3PO4 or ZnCl2 and/or physical activation with CO2. Efforts were focused to establish relationships among the activation procedure, the textural and physical-chemical properties of the resulting materials and their volumetric CH4 uptake. The best results were achieved by using the combination of a relatively soft chemical activation with H3PO4 or ZnCl2, just the sufficient to minimize the presence of macropores originated from the botanical structure of the precursor, followed by physical activation with CO2 to develop a narrow pore size distribution mainly located around the optimum pore diameter/width for CH4 storage. This combined methodology permitted to obtain excess volumetric CH4 adsorption capacities as high as 94, 148 and 145 V/V for granular, powdered/compressed and monolithic carbons, respectively. The corresponding total CH4 storing capacities were estimated to be 102, 165 and 163 V/V. It is worthy to highlight that the precursor was a low cost and abundant agricultural by-product, which is very important for large-scale applications such as gas transportation and gas storage in vehicular fuel tanks.

Unconventional pretreatment, that is, delignification and the addition of guanidine phosphate, was performed for the synthesis of activated carbon having a high specific surface area from bamboo by physical activation. The values of the specific surface area, total pore volume, and average pore size depended on the amount of added guanidine phosphate and the CO2 activation time. The amount of the added guanidine phosphate under the optimum conditions for the highest specific surface area was much lower than that of the phosphorous acid chemical activator under conventional conditions. The N2 adsorption isotherms of all the samples were type I, which means that micropores were dominant. The pore sizes of the samples in this study were similar to that of the physically-activated carbon. Therefore, the activation process was presumed to be essentially not chemical, but physical. The relation between the yield and the specific surface area improved with the addition of guanidine phosphate. The reason for the improvement may be the change in the reactivity of the carbon material generated during the heating process. The maximum specific surface area was ca. 2000 m2 g−1, which is a high value for a physically-activated carbon.

We have analyzed the effects of CO2 activation on the porosity of ultrahigh pore volume carbon aerogels. Data obtained from the new 2D-NLDFT-HS model for carbons has been compared to the results of conventional methods (BJH, t-plot, DR); all the models were applied to the desorption branch of the isotherms. Physical activation of the carbon aerogel at different burn-off degrees resulted in materials showing increasing volume of micropores and alteration of mesopore structure. The later effect manifested itself by a characteristic inflection in the desorption branch of the nitrogen isotherm at high relative pressures. Such curvatures are attributed to a non uniform activation of the carbon matrix with CO2 that in some parts carves the surface of the precursor deeper than in others, creating bimodal/multimodal pore size distributions. The different methods applied for the assessment of the textural properties of the aerogels with ultrahigh micro-/mesoporosity showed excellent agreement in terms of pore volumes, surface areas and average pore size.

Biomass residues have been used to produce activated carbons. On this process, the activation method and the raw composition determine the properties as porosity and surface area of the charcoal. After the extraction of castor oil, there is a solid byproduct (cake) of low added value, which was used in the production of activated carbon to add value to this waste. For this purpose two traditional methods were used, first, physical activation using as activating agents steam, CO2 and mixture of both, and additionally chemical activation using K2CO3 as the activating agent. Some activated carbons were characterized using N2 adsorption isotherms, BET surface areas varied between 255.98 (m2/g) and 1218.43 (m2/g). By SEM and EDS analysis was possible to observe that materials obtained by the two types of activation are principally amorphous and morphological characteristics of the carbon obtained by physical activation are very different from those obtained by chemical activation. Finally, through impregnation of inorganic phases of Ni and Mo was revealed that the high dispersion characteristics, these carbonaceous materials will have potential to be used as catalyst support., Los residuos de biomasa han sido usados para la producción de carbones activados, en este proceso, el método para obtenerlos y la materia prima determinan propiedades como la porosidad y área superficial del carbón. Tras la extracción del aceite de higuerilla se genera un subproducto sólido (torta) de difícil salida, que fue usado en la producción de carbón activado, en busca de la valorización de este residuo sólido. Para tal fin se emplearon dos métodos tradicionales. En primer lugar, activación física usando como agentes activantes vapor de agua, CO2 y una mezcla de estos gases, adicionalmente se realizó activación química usando K2CO3 como agente activante. Algunos de los carbones obtenidos fueron caracterizados usando isotermas de adsorción/desorción de N2 donde se lograron áreas superficiales BET entre 255,98 (m2/g) y 1218,43 (m2/g), del análisis por SEM y EDS se encontró que los materiales obtenidos por ambos tipos de activación son principalmente amorfos y que las características morfológicas de los carbones obtenidos mediante activación física son muy diferentes de los obtenidos por activación química. Finalmente, a través de impregnación con sales de Ni y Mo se evidenció que por características como la alta dispersión obtenida, estos materiales carbonosos presentan un potencial para ser usados como soporte catalítico.

Biomass residues have been used to produce activated carbons. On this process, the activation method and the raw composition determine the properties as porosity and surface area of the charcoal. After the extraction of castor oil, there is a solid byproduct (cake) of low added value, which was used in the production of activated carbon to add value to this waste. For this purpose two traditional methods were used, first, physical activation using as activating agents steam, CO2 and mixture of both, and additionally chemical activation using K2CO3 as the activating agent. Some activated carbons were characterized using N2 adsorption isotherms, BET surface areas varied between 255.98 (m2/g) and 1218.43 (m2/g). By SEM and EDS analysis was possible to observe that materials obtained by the two types of activation are principally amorphous and morphological characteristics of the carbon obtained by physical activation are very different from those obtained by chemical activation. Finally, through impregnation of inorganic phases of Ni and Mo was revealed that the high dispersion characteristics, these carbonaceous materials will have potential to be used as catalyst support., Los residuos de biomasa han sido usados para la producción de carbones activados, en este proceso, el método para obtenerlos y la materia prima determinan propiedades como la porosidad y área superficial del carbón. Tras la extracción del aceite de higuerilla se genera un subproducto sólido (torta) de difícil salida, que fue usado en la producción de carbón activado, en busca de la valorización de este residuo sólido. Para tal fin se emplearon dos métodos tradicionales. En primer lugar, activación física usando como agentes activantes vapor de agua, CO2 y una mezcla de estos gases, adicionalmente se realizó activación química usando K2CO3 como agente activante. Algunos de los carbones obtenidos fueron caracterizados usando isotermas de adsorción/desorción de N2 donde se lograron áreas superficiales BET entre 255,98 (m2/g) y 1218,43 (m2/g), del análisis por SEM y EDS se encontró que los materiales obtenidos por ambos tipos de activación son principalmente amorfos y que las características morfológicas de los carbones obtenidos mediante activación física son muy diferentes de los obtenidos por activación química. Finalmente, a través de impregnación con sales de Ni y Mo se evidenció que por características como la alta dispersión obtenida, estos materiales carbonosos presentan un potencial para ser usados como soporte catalítico.

A particular environmental problem is a growing generation and the difficulties in the disposal of waste tires. The European Union, USA, and Japan produce around 6 million tons of scrap tires per year; while in the entire world generate 1 billion of waste tires. Tires are an environmental passive produced by several sectors of the industry and human activity. The mining industry is closely related to the disposal of ELTs of high tonnage, yet, this sector has not proposed a possible solution to treat this type of waste. Commonly, landfill zones are the primary destiny of tires, where they represent hazards such diseases and accidental fires. Actual treatments such as energy recovery in cement kilns and recycling process do not offer an integral way to benefit the end life tires (ELT). However, pyrolysis has shown to be an alternative treatment, and an attractive way to recover valuable products such as combustible gases, fuel, and carbon. The last one is of interest in this research because it is the precursor in the production of activated carbon. This treatment proposes a possible solution to take profit of waste tires of mining industry. The main purpose of the present work was to prepare activated carbon from waste tires, which is suitable as an adsorbent of relatively large molecules. Small pieces of rubber (2-3 cm) from the sidewall of tires were used into the experimentation. The pyrolysis tests were developed into laboratory and pilot scales under temperatures between 450-550 °C. The physical activation of the char was carried under CO2 atmosphere and temperatures between 850-900 °C. The methods of iodine index, blue-methylene adsorption, and sugar index were used to determinate the specific area, and the adsorption capacity of activated carbon. Pyrolysis results demonstrated that residence times superior to 45 min were necessary to get a char with a high content of fixed carbon with an overall weight loss constant of 67%. Activated carbon with a specific are

This paper presents a novel method of manufacturing carbon foams from coals with a bimodal porosity structure (macro- and microporosity), by means of a carbonization process at 450 or 475 °C that produces the carbon foam, followed by chemical activation with zinc chloride at 500 °C. The activation agent influences the development of macroporosity during the foaming step and gives rise to microporosity (major pore sizes in the 0.6–1.1 nm range) and a specific surface area (up to 762 m2 g–1) in the activation step. A coal with a lower volatile matter content and less fluidity gives rise to carbon foams with a higher macropore volume but a lower macropore size., A higher gas flow and a longer soaking time in the activation step lead to a larger micropore volume and a higher surface area. Foams with a still significant micropore network can be obtained by performing simultaneous chemical (with ZnCl2) and physical (with CO2) activations at 800 °C. Presumably, such foams would display higher mechanical strength and electrical conductivity.

Activated carbons are one of the most used adsorbents with lots of applications in many sectors. Activated carbons can be produced from lignocellulosic materials with a large content of carbon. Coffee is the second trade most consumed all over the world; hence their residues can be treated in order to give a value. In order to evaluate the viability of using coffee residues as precursor have been carried out experiments by chemical and physical activation. The chosen chemical was phosphoric acid, a dehydrating chemical widely used in production of activated carbons while steam was selected for a physical activation. In this study have been studied the temperature activation and the concentration of chemical as the main factors. One of the advantages of using a chemical is the lower activation temperature; in this study were selected 500ºC, 600ºC and 700ºC while samples treated by steam were 600ºC, 700ºC and 800ºC. Water is a reactive agent that removes volatile compounds and makes wide pores whereas chemicals create linkages with the carbon and volatile compounds enhancing their porosity. Hence, have been studied the following impregnation concentrations 30%, 40% and 50% in order to evaluate their properties as adsorbents. Isotherms were analysed to determine their surface area and pore size distribution. Also were determined the pore size and pore volume for all samples.

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), VDR(CO2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), VDR(CO2). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

Activated carbons are one of the most used adsorbents with lots of applications in many sectors. Activated carbons can be produced from lignocellulosic materials with a large content of carbon. Coffee is the second trade most consumed all over the world; hence their residues can be treated in order to give a value. In order to evaluate the viability of using coffee residues as precursor have been carried out experiments by chemical and physical activation. The chosen chemical was phosphoric acid, a dehydrating chemical widely used in production of activated carbons while steam was selected for a physical activation. In this study have been studied the temperature activation and the concentration of chemical as the main factors. One of the advantages of using a chemical is the lower activation temperature; in this study were selected 500ºC, 600ºC and 700ºC while samples treated by steam were 600ºC, 700ºC and 800ºC. Water is a reactive agent that removes volatile compounds and makes wide pores whereas chemicals create linkages with the carbon and volatile compounds enhancing their porosity. Hence, have been studied the following impregnation concentrations 30%, 40% and 50% in order to evaluate their properties as adsorbents. Isotherms were analysed to determine their surface area and pore size distribution. Also were determined the pore size and pore volume for all samples.