Production Of Carbon Materials Research Articles

Options for processing of aspen wood to carbon materials

.Thermochemical processing of aspen wood to produce carbon materials is of interest considering that it allows increasing the cost of its products several times and enhancing the sustainability of forest complex enterprises.Currently, the enterprises are confined to the manufacture of charcoal, although it is possible to produce other carbon materials, such as charcoal briquettes, activated carbon and oxidized coal.While processing aspen wood, it is feasible to arrange manufacturing charcoal briquettes. Increased mechanical strength and high bulk density of briquettes raises the range of economically viable transportation of manufactured products, i.e. logistics is being improved.To obtain stable quality activated carbon from aspen coal, water vapor activation is the least environmentally hazardous. For such activation implementation, we recommend using a rotary kiln equipped with a Z - shaped insert. For reasons of environmental safety, the oxidation of activated carbon is preferably carried out using hot, humid air. In this case, unlike liquid-phase oxidation, no wastewater is formed.

Cross-Polymerization between the Typical Sugars and Phenolic Monomers in Bio-Oil: A Model Compounds Study

Bio-oil tends to polymerize on heating, and understanding the mechanism by which it occurs is of importance for developing the methods for enhancing the polymerization of bio-oil to produce carbon materials or to minimize the polymerization in hydrotreatment. This study mainly investigated the potential cross-polymerization between the typical sugars (xylose and glucose) and phenolics (vanillin and guaiacol) in bio-oil with water as the reaction media in the presence/absence of H2SO4. The results showed that vanillin displayed a high tendency toward polymerization in both the presence/absence of H2SO4, originating from its carbonyl functionality, while guaiacol was quite stable. Nevertheless, in the coexistence of xylose or glucose, guaiacol or vanillin could effectively cross-polymerize with the sugars, resulting in the higher conversion and higher yields of the solid product. During the cross-polymerization, the dehydration of the sugars did not occur substantially, resulting in the high oxygen content and the low thermal stability of the resulting polymers. In addition, in the H2SO4-catalyzed cross-polymerization between vanillin and sugars, the carbonyl functionality was consumed while it was retained in cross-polymerization of guaiacol and sugars, indicating the distinct mechanism for the polymerization.

Comparative analysis of petroleum and coal pitches using 1H and 13C NMR spectroscopy

Petroleum and coal pitches are known to be among the most important sources of raw materials for the production of carbon materials, including electro-carbon, heat- and chemical-resistant structural products, metal-carbon and carbon-carbon composite materials, graphite electrodes, self-baking anode paste, carbon fibres, blast furnace and cupola coke. The quality of the pitches is determined by the elemental and group composition, as well as their structural and physical-chemical properties. The study of the molecular structure and group composition of the organic components of the pitch and the identification of the effect of the composition on the performance of the products is of great interest for assessing the prediction of the behaviour of pitches during processing and the properties of the products obtained from them. The present work is devoted to the study of the group composition of two petroleum and two coal pitches using high-resolution NMR spectroscopy. The data of the ¹H and ¹³C NMR spectra allow the composition of the pitch product to be estimated without separation into fractions, which, in turn, combined with the accuracy of the method and the recording speed of the ¹H NMR spectra, increases the rapidity of this method of analysis. The combination of ¹N and ¹³C NMR data allows additional information on the correlation of physical parameters and pitch composition to be established. The calculation of the (H ar /H al ) parameter, corresponding to the ratio of the integral intensities of signals of aromatic and aliphatic hydrogen atoms, provides the possibility of using it as a structural characteristic for a particular sample. In order to ensure the correct contribution to the integral intensity of the signals, ¹³C NMR spectra were recorded in a pulse sequence with suppression of the spin-spin proton interaction only for the period of data reading for the purposes of minimising the nuclear Overhauser effect. The relaxation delay between pulses was set to 10 s. The study of petroleum and coal pitches using NMR spectroscopy showed the proton spectra of NMR data to be sufficiently informative and suitable for monitoring the technological process of pitch production.

Combined Effect of Pressure and Carbon Dioxide Activation on Porous Structure of Lignite Chars.

Lignite is an important natural resource with the application potential covering present and future energy systems, including conventional power plants and gasification systems. Lignite is also a valuable precursor for the production of porous materials of tailored properties for various environmental applications, including the removal of contaminants from gaseous or liquid media. Although the lignite-based activated carbons are commercially available, various approaches to produce carbon materials of desired properties are still being reported, covering temperature, partial oxidation and chemical activation effects on surface and structural properties of these materials. Limited data is, however, available on the effects of pressure as the activation parameter in shaping the porous structure of carbonaceous materials, in particularly lignite-derived. In the study presented the combined effect of carbon dioxide activation and pressure in the range of 1–3 MPa at the temperature of 800 °C on the development of porous structure of lignite chars was reported. The study was also focused on poor-quality resources valorization by using a relatively low calorific value, low volatiles and high ash content lignite as a carbon material precursor. The results showed that the application of pressure in carbon dioxide-activation process at 800 °C results in generation of chars of comparable or higher specific surface area than the carbon materials previously received with demineralization and carbon dioxide activation of lignite. They also proved that the combined pressure and carbon dioxide activation may be effectively applied in conversion of low quality lignite into valuable porous materials.

Advancements and potentials of molten salt CO2 capture and electrochemical transformation (MSCC-ET) process

Abstract Electroreduction of CO2 in molten salts, also called molten salt carbon capture and electrochemical transformation (MSCC-ET), can convert CO2 into value-added carbonaceous materials or CO in a comparably high rate with high energy efficiency. It shows a promising potential to contribute to the earth's atmospheric carbon balance, the intermittent renewable energy storage, carbon materials production, and air quality control of the local environment. This short review briefly introduces the principle of the MSCC-ET process, the state-of-the-art of the process, its potential of commercialization in terms of process efficiency, product marketing and economy, and finally, the opportunities and challenges in future research and development.

Nitrogen and oxygen dual-doped activated carbon as electrode material for high performance supercapacitors prepared by direct carbonization of amaranthus

With supercapacitors application promotion, looking for simple, energy efficient and environment-friendly method for expandable production of carbon materials with uniform heteroatoms doping as high-performance electrode materials for supercapacitors becomes the keystone of current research. Here, we present a simple, not costly, low environmental pollution method for preparation of nitrogen and oxygen dual-doped activated carbons via one step direct carbonization of natural, renewable and abundant amaranthus followed by ultrasonic treatment with nitric acid. Most noteworthy is XC-700-50, which exhibits high conductivity, moderate surface area, reasonable pore size distribution and high O and N doping contents (12.05% and 5.31% respectively). Benefiting from these features, it displays high gravimetric capacitance (326 F g−1 and 294 F g−1 at 0.5 A g−1 and 1 A g−1, respectively), good rate capability, as well as excellent cycling stability (about 97.1% and 94.4% of capacitance retention after 10000 cycles at 2 A g−1 and 10 A g−1, respectively) in the high mass loading electrode (8 mg cm−2), making it a promising electrode material for supercapacitors.

Exploring the influence of solar pyrolysis operation parameters on characteristics of carbon materials

Carbon materials can be produced by different methods, one of them is solar pyrolysis, which is attaining renewed interest due to simplicity to transform biomass with environmental advantages. However, pyrolysis operation parameters are decisive factors that determine the morphological and chemical properties of carbon. This work aims to study the influence of temperature and heating rate of solar pyrolysis in the properties of carbon. Pyrolysis experiments were carried out in the 25 kW IER-UNAM solar furnace. Agave biomass was processed in a glass spherical solar reactor. Temperatures between 500 and 900 °C were utilized, as well as heating ramps between 4 and 30 °C/min. Samples were analyzed with several techniques. The results of the experiments indicate that solar pyrolysis temperature and heating rate scarcely impact the carbon composition, however the structure, surface area and electrochemical response are highly affected by both. The control of the operation conditions allows to produce carbon materials that exhibit promising properties to be used as catalyst supports for polymer electrolyte membrane fuel cells and electrolyzer cells applications. Therefore the use of concentrated solar energy represents an attractive method to obtain these valuable materials.

ZnO@ porous graphite nanocomposite from waste for superior photocatalytic activity.

In this work, a new type of advanced 3D mesoporous carbon nanocomposites derived from Zn dust/PET bottle mixed waste with a high surface area is created. Interestingly, simultaneous transformation of Zn metal into ZnO nanoparticles and PET bottle waste to porous carbon materials occurred upon thermal treatment at 700°C. The effect of the amount of Zn metal on the prepared materials has been studied. The carbon material-based waste presented very large surface area (up to 684.5m2/g) with pore size distribution (18.47-16.88nm). The SEM and TEM analysis revealed that the produced carbon materials have 3D porous dense layers with a gradient pore structure. The created waste-based nanocomposite exhibited an enhanced photocatalytic performance for the degradation of organic dyes (methylene blue and malachite green). It is believed that the presented work not only provides a sustainable approach to the creation of new nanocomposites of ZnO-mesoporous carbon materials for the application in photocatalysis but also introduces a new way of upcycling of mixed waste materials.

Synthesis of carbon nanofiber from horse manure via hydrothermal carbonization for dye adsorption

Abstract The livestock manure was suddenly concerned due to the crucial reason of greenhouse gases emission. Therefore, several technologies were applied to manage these waste materials such as fertilizer production, biogas or carbon material production. In this study, horse manure, a novel fibrous feedstock, was supplied to produce a carbon nanofiber for metal catalyst supporter and dye adsorbent. Carbon nanofiber was performed via hydrothermal carbonization at 200°C for 24 hours followed by carbonization at the temperature range of 300 to 900°C under the nitrogen atmosphere for 2 hours. Basically, the production yield, chemical compounds, surface morphology and pore size of produced carbon nanofiber were investigated. Dye adsorption capacity was increased by increase of carbonization temperature.

High yields of solid carbonaceous materials from biomass

A method was developed for the production of carbon materials from biomass with high yields/strength via cross-polymerizing bio-oil, furfural and biochar.

The Inductive and Capacitive Characteristics of Carbonate-Derived Carbons

Due to the increasing modern dependence on electronic devices, the production of carbon materials for supercapacitive and battery-based applications is an area of current research and innovation. It has been known for a considerable time that carbons can be formed through the electrolytic reduction of molten carbonate salts [1], however, little research has been put into in-depth understanding of the electrochemical characteristics of these materials. Electrochemical impedance spectroscopy can tell us a lot about the suitability of these materials for supercapacitive applications. This research investigates how the characteristics of carbons derived through molten carbonate reduction change based on synthesis conditions, with a particular focus being placed on the inductive and capacitive behaviour of the materials and on how inductances arise (Figure 1 (i)). This is done through the application of equivalent circuit modelling (Figure 1 (ii)) to cells constructed from synthesised and activated carbons, and the subsequent mathematical modelling of the system using complex non-linear least squared error curve fitting (CNLS) based on the interior-point algorithm in the MATLAB program. The frequency-dependant capacitance of the materials (Figure 1 (iii)) is reported and used as a point of comparison. Optimal carbon synthesis conditions of 500°C or low deposition current densities of 0.15 A/cm2 have been found to both reduce inductive behaviour, and to produce carbons with capacitances as high as 160 F/g, close to 90% of that of the examined activated carbon. [1] Hughes, M.A., J.A. Allen, and S.W. Donne, Carbonate Reduction and the Properties and Applications of Carbon Formed Through Electrochemical Deposition in Molten Carbonates: A Review. Electrochimica Acta, 2015. 176: p. 1511-1521. Figure 1

Nano-Scale Soot Particle Formation During the High-Temperature Pyrolysis of Waste Plastics in an Entrained Flow Reactor

Advanced carbon material production via pyrolysis is an economical process for the recycling-utilization of waste plastics. The purpose of this study is to demonstrate the characteristics and formation mechanism of nano-scale soot particles from waste plastic pyrolysis at high temperatures. Waste rigid polyurethane (PU) was adopted to decompose in an entrained flow reactor at 1000, 1100, 1200, and 1300 °C. The yield, morphology, elemental composition, chemical and crystal structure, and reactivity of soot particles, and the yield and composition of gas products were measured and characterized. Results show that with the temperature increasing from 1000 to 1200 °C, the soot yield increases from 12.2 to 26.5 wt%, while with the temperature increasing to 1300 °C, the change on soot yield is slight. The morphology analysis by scanning transmission electron microscopy indicates that the inception of soot particles starts at 1100 °C, when the onion layered structure of spherical particles (20–50 nm) is observed. With increased temperature, the soot particle size becomes smaller and more uniform. Fourier transform infrared analysis and X-ray diffraction characterization present more C=C functional groups and better graphite structures at higher temperatures, agreeing with the increased carbon content in soot. The oxidation reactivity of soot particles generally increased with the increase of pyrolysis temperature. NaCl is observed in soot particles when the pyrolysis temperature is higher than 1100 °C, as an efficient catalyst, significantly enhances the ignition and burnout of soot particles. The soot formation pathway during plastic pyrolysis is finally proposed based on the measurement of representative gases.

Production of Carbon Materials with Specified Porosity

The results of studies on the oxidation of carbon black are represented. It was found that materials with different porosity can be obtained by varying the nature of an activating agent and the conditions of activation. A correlation of the sizes of carbon crystallites in the initial sample, the extent of their boundaries, and the rates of pyrocompaction and oxidation of these samples with the specific surface area of materials obtained upon activation was established.

Starch-Derived Hierarchical Porous Carbon with Controlled Porosity for High Performance Supercapacitors

The development of green and clean synthetic techniques to produce carbon materials for energy storage and conversion applications has motivated researchers to use sustainable biomass. In this study, hierarchical porous carbon (HPC) with very high specific surface area and controlled porosity is synthesized by a novel and facile method, which employs an exothermic pyrolysis process of starch–magnesium nitrate raw materials with subsequent high temperature thermal treatment and acid washing. The biomass starch acts as both a reductant and carbon source, while magnesium nitrate is an oxidant and provides MgO template as pore creator. The vigorous exothermic pyrolysis of starch–magnesium nitrate mixture introduces MgO@C precursor with a highly 3D porous network containing meso- and macropores. After MgO template is removed, plenty of micro- and mesopores are further created. Experimental parameters including calcination temperature, starch–nitrate ratio, and magnesium salt species are comprehensively evaluat...

Theoretical and Experimental Investigations of Substantiating Technologies for Carbon Materials Production from Natural Gas

The results of theoretical and experimental investigations on methane pyrolysis with infiltration through a heated porous matrix generated from various carbon materials are presented. The features of mathematical<br />models, kinetic relationships of process are discussed. The mathematical model of process shares on external problem (a flow of particles in an external stream) and internal problem (reaction in particle porous). The<br />heat and mass transfer for the average (over the reactor cross section) parameters, ignoring the heat transfer in gas by thermal conductivity, is described by unsteady-state one-dimensional differential equations in<br />partial derivatives. For the mathematical description of process kinetics of methane decomposition the approach is used by which the soot formation is treated as a chain radical process. The porous media is represented by a system of large enough particles. In its turn, every macroparticle consists of finer particles, which are also composed of microparticles, etc. Calculating programs were used for modeling and efficiency analysis of technological installations for technical carbon production in a regenerative heater, filled by a ceramic nozzle and for similar purposes concerning carbon (oven soot) in autothermal torch process of partial gas oxidation by air at a surplus factor of oxidizer in relation to stoichiometry 0.4-0.5 at pressure close to atmospheric on Sosnogorsk Gas-Processing Plant. Experiment descriptions and techniques for experimental realization are given. These results are used as fundamentals for new technologies considering pyrocarbon materials production in the continuous operation reactor.

Valorization of algal waste via pyrolysis in a fixed-bed reactor: Production and characterization of bio-oil and bio-char

The aim of the present work is to develop processes for the production of bio-oil and bio-char from algae waste using the pyrolysis at controlled conditions. The pyrolysis was carried out at different temperatures 400–600°C and different heating rates 5–50°C/min. The algal waste, bio-oil and bio-char were successfully characterized using Elemental analysis, Chemical composition, TGA, FTIR, 1H NMR, GC–MS and SEM. At a temperature of 500°C and a heating rate of 10°C/min, the maximum yield of bio-oil and bio-char was found to be 24.10 and 44.01wt%, respectively, which was found to be strongly influenced by the temperature variation, and weakly affected by the heating rate variation. Results show that the bio-oil cannot be used as bio-fuel, but can be used as a source of value-added chemicals. On the other hand, the bio-char is a promising candidate for solid fuel applications and for the production of carbon materials.

High energy supercapacitors based on interconnected porous carbon nanosheets with ionic liquid electrolyte

Future development of electrochemical energy storage systems requires low-cost supercapacitors with not only an outstanding power performance but also the high energy. Herein, interconnected porous carbon nanosheets are prepared via a simple hydrothermal process combined with chemical activation route by using reed as the precursor and KOH as the activating agent. The as-prepared carbon nanosheets exhibits a high specific surface area (up to 2183 m2 g−1), and a hierarchical porous structure containing combined macroporous scaffolds and meso/microporous textures. When tested as electrode materials for ionic liquid-based supercapacitors, the carbon nanosheet exhibits a high capacitance of 147 F g−1 and a good capacitance retention ratio of 48.3% at 100 A g−1, with a high cycling life stability (10% loss after 10000 cycles). Moreover, the assembled supercapacitor yields a maximum energy and power density of 11.4 Wh kg−1 and 98 kW kg−1 based on the all components of the packaged device. The remarkable characteristics of the produced carbon materials indicate that the novel precursor-synthesis route offers promising potential for low-cost production for supercapacitors.

The Prospects of Functionalized Cellulose-based ‘Papers’ as Electrode Materials in Electrochemical Conversion and Storage Devices

With rapid development of the global economy, increasing environmental pollution and the depletion of fossil fuels, there is a vital need for clean, sustainable and efficient sources of energy as well as new technologies allied with energy conversion and storage (1). Among many application fields, some of the most practical and efficient technologies for electrochemical energy conversion and storage are fuel cells, batteries and electrochemical supercapacitors. In recent years, these devices have attracted significant attention, each with recognized advantages. Driven by this need and the promise of the technology, significant progress in practical and theoretical research and development of these devices has taken place. One of the challenges of developing these electrochemical energy conversion and storage technologies is the use of low cost and readily available materials that possess complex requirements of different applications. To overcome obstacles of high costs of raw materials and avoid usage of depleting sources, bio-based carbon materials are believed to lead the next generation of many industries including aerospace, sports equipment and electrochemical devices due to their abundance, high chemical stability, electrical conductivity, low cost and non-toxicity, high specific surface area and wide operating temperature range (2). The feasibility of the carbon precursors in different electrochemical devices for practical applications including hybrid power sources in electrical vehicles, burst-power generation in electronic devices, back-up power sources, portable and stationary equipment has been demonstrated. Cellulosic fibers in nano and micro scale, the green and most abundant material, have eco-friendly attributes that are economically and technically feasible to replace man-made fibers (3). Carbonization of cellulose yields carbons, including charcoal, activated carbon and graphite fibers. The process comprises of introducing the fibers in an inert atmosphere, preheating and drying the fibers, treating the dried fibers up to a certain temperature at which they carbonize by evolution of a purging gas and finally cooling the carbonized residues (4). The produced carbon materials have been investigated as a potential material in different electrochemical devices and have proved to have prospect as electrode materials for supercapacitors, catalyst supports in fuel cells and membrane separators in lithium-ion batteries. In this project, bio-based cellulosic starting materials have been investigated as a candidate for supercapacitor electrode materials. The produced activated carbon materials upon carbonization of the cellulose fibers have been functionalized and characterized by different techniques to study the effect of the morphology and surface area of the carbonaceous residues on their performance in the electrochemical device. This work has been coupled with a range of electrochemical tests in two and three-electrode systems including cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge loop tests. The work highlights the importance of relating the different characterization techniques of the raw and produced materials and the effect of each on the performance of the activated carbons as electrode materials in supercapacitors.

Influence of binder on the porosity of carbon materials

The formation of porosity in carbon materials is considered. In hot-pressed materials with medium-sized grains, porosity is formed by the destruction of binder when blanks are fired to 600°C. In cold-pressed small-grain materials, shrinkage and binder destruction are responsible for the porosity. Up to 600°C, the yield of volatiles and shrinkage compensate the development of porosity, which mainly appears above 600°C. Using various binders, we may obtain carbon materials with small or large porosity. In addition, the binder affects the pore size and distribution. Methods of producing carbon materials with elevated porosity are considered, including the use of filler from a single size fraction and the use of pore-forming agents, Highly porous carbon materials are also produced from binder, with no filler. The raw materials employed are synthetic tars or mesophase pitch. The properties of carbon materials with different pore content are compared.

Coniferous pine biomass: A novel insight into sustainable carbon materials for supercapacitors electrode

Low-cost biomass-derived activated porous carbon from natural pine cones is synthesized using hydrothermal approach followed by KOH activation and carbonization. The produced carbon materials have a high surface area of 1515 m2 g−1 with a well-developed meso/micropores structure which is advantageous and favorable for mass transfer and ion accommodation for fast rate performance by providing pathways for electrolyte permeation and contact probability. Symmetric device fabricated using the obtained carbon material as electrode, exhibited good electrochemical performance with no degradation of capacitance after voltage holding at 1 V for about 60 h demonstrating good rate capability of the fabricated device. The results demonstrate the exciting potential of the pine cone derived carbons as a promising candidate for high-performance electrode materials for supercapacitors if fully explored.