Search Results (31)

Carbon black (CB) serves as the most crucial reinforcing filler in natural rubber (NR) applications. However, conventional CB production relies on petroleum or coal resources, raising concerns about non-renewability and unsustainable resource consumption. Although biomass-derived carbon materials have been explored as alternatives for natural rubber reinforcement, their practical application remains constrained by inherent limitations such as large particle size and low graphitic structure, which compromise reinforcement efficiency. This study presents a novel walnut shell biochar (WSB) for natural rubber enhancement. The biochar was prepared via conventional pyrolysis and subsequently subjected to an environmentally friendly physical ball-milling process. This treatment effectively increased graphitized domains while enriching surface functional groups. Systematic investigations were conducted on the effects of ball-milling duration and biochar loading on rubber reinforcement performance. Results demonstrate that the biochar-reinforced vulcanizates achieved a 22% improvement in tensile strength compared to unfilled rubber. Notably, at 10 phr loading, the tensile strength of biochar-filled vulcanizates reached 98% of that achieved by CB(N330)-filled counterparts. The study further revealed that biochar incorporation effectively reduced hysteresis loss and enhanced elastic recovery in rubber composites. This work proposes a facile method to develop sustainable biochar-based reinforcing agents with significant potential for natural rubber applications. Full article

Graphite-phase carbon nitride (CN) has the advantages of high stability, non-toxicity, and harmlessness in degrading antibiotic pollutants in water. How to achieve the reduction of its electron-hole complexation efficiency as well as the improvement of its recyclability, while at the same time ensuring these advantages, is the focus of this paper. In this study, modified magnetic particles selected from coal gasification slag were used as carriers, which were compounded with CN and then subjected to a simple roasting process to obtain composite magnetic photocatalysts (MCN) with different ratios. The introduction of porous magnetic carriers increased the specific surface area of MCN, provided more active sites, and effectively improved the migration ability and redox capacity of CN carriers. Among them, 50% MCN showed excellent photodegradation performance, and the removal rate of tetracycline reached 82% within 60 min, which was much higher than that of CN. 50% MCN has a saturated magnetisation intensity of 1.55 emu·g⁻¹, which can be regenerated after recycling using a magnetic field, and the degradation efficiency of tetracycline is still more than 70% after five cycles, indicating that 50% MCN has good stability. This work demonstrates that magnetic gasification slag as a modified carrier can effectively promote the separation of photogenerated electron-hole pairs of graphite-phase carbon nitride, which provides a reference for the resourceful utilisation of coal gasification slag, as well as for the construction of g-C₃N₄-based photocatalysts with highly efficient and stable photodegradation activity. This work exemplifies how waste-derived materials can advance photocatalyst design, addressing both efficiency and sustainability challenges in water treatment. Full article

Graphite made from coal will not only widen the graphite mineral resource, but also significantly improve the value of coal utilization. In this study, anthracite coal was heated in the temperature range of 500 to 2900 °C to study the size increase of nanometric graphite crystallites from anthracite to real graphite. The carbon content rapidly increases to 99.2% when heated from room temperature to 1600 °C, and then gradually increases to 100% when the treated temperature increases to 2900 °C. The FTIR results show that methyl, methylene, and aromatic hydrocarbon, preexisting in the raw anthracite, were preserved in the JZS-500 sample, but that when the treated temperature ≥ 1000 °C, these C-H bonds almost disappear. The basic structural units (nano graphitic carbon) grow into distorted columns, and the basic structural units and micro-columns re-oriented and coalesced to form local molecular oriented domains with the temperature increase from anthracite to JZS-1500. When the temperature ≥ 1600 °C, amorphous carbon, onion-like carbon, turbostratic layers, and graphitic carbon co-occur within the graphitized coals. At the sub-micron scale, carbonization is a homogenous process, whereas graphitization is a heterogenous process. The average graphite crystalline size (L_a, lateral extension; L_c, stacking height) rapidly increases as the treatment temperature increases from 1600 to 2300 °C. Three coal structural transformation stages were classified according to the nanometric carbon structural evolution with temperature. This study will contribute to the efficient and value-added utilization of coal to make graphite materials. Full article

When compared to natural graphite, artificial graphite has advantages such a longer cycle life, faster charging rates, and better performance. However, the process of producing it, which frequently uses coal, raises questions about the impact on the environment and the depletion of resources. Eco-friendly, wood-based graphite must be developed in order to solve these problems. This study assessed and investigated the characteristics of charcoals derived from bamboo and oak which were utilized to produce graphite. After heating to 1500 °C at 10 K/min, 86.87 wt% of oak charcoal and 88.33 wt% of bamboo charcoal remained, indicating a yield of more than 85% when charcoal was graphitized. Depending on the species of wood, different-sized pores showed different shapes as the graphitization process advanced, as revealed by SEM surface analyses. The carbon atoms seen in the XRD crystal development changed into graphite crystals when heated to 2400 °C, and the isotropic peaks vanished. Bamboo charcoal has a higher degree of crystallinity than other wood-based charcoals, such as oak charcoal, which is made up of turbostratic graphite, according to Raman spectroscopic research. Lithium-ion batteries employ bamboo charcoal as their anode material. At this point, the values for soft carbon were determined to be 196 mAh/g and for hard carbon to be 168 mAh/g at a current density of 0.02 A/g. Full article

Carbon-based electrodes have recently been most widely used in P-MFC due to their desirable properties such as biocompatibility, chemical stability, affordable price, corrosion resistance, and ease of regeneration. In general, carbon-based electrodes, particularly graphite, are produced using a complex process based on petroleum derivatives at very high temperatures. This study aims to produce electrodes from bio-pitch and charcoal powder as an alternative to graphite electrodes. The carbons used to manufacture the electrodes were obtained by the carbonisation of Robinia pseudoacacia and Azadirachta indica wood. These carbons were pulverised, sieved to 50 µm, and used as the raw materials for electrode manufacturing. The binder used was bio-pitch derived from coconut shells as the raw materials. The density and coking value of the bio-pitch revealed its potential as a good alternative to coal-tar pitch for electrode manufacturing. The electrodes were made by mixing 66.50% of each carbon powder and 33.50% of bio-pitch. The resulting mixture was moulded into a cylindrical tube 8 mm in diameter and 80 mm in length. The raw electrodes obtained were subjected to heat treatment at 800 °C or 1000 °C in an inert medium. The electrical resistivity obtained by the four-point method showed that N1000 has an electrical resistivity at least five times lower than all the electrodes developed and two times higher than that of G. Fourier-transform infrared spectroscopy (FTIR) was used to determine the compositional features of the samples and their surface roughness was characterised by atomic force microscopy (AFM). Charge transfer was determined by electrical impedance spectroscopy (EIS). The FTIR of the electrodes showed that N1000 has a spectrum that is more similar to that of G compared to the others. The EIS showed the high ionic mobility of the ions and therefore that N1000 has a higher charge transfer compared to G and the others. AFM analysis revealed that N1000 had the highest surface roughness in this study. Full article

Due to the severe harmful impacts of industrial dyeing wastewater on ecosystems and human health, proper treatment is crucial. Herein, the use of modified graphite as an adsorbent for dyeing wastewater treatment was investigated in this study. The graphite was oxidized and intercalated using a phosphoric acid–nitric acid–potassium permanganate system and then thermally treated at high temperatures to optimize its structure. By adjusting the thermal treatment temperature, the graphite adsorbent with varying porosity was obtained. The optimized graphite demonstrated significant improvement in adsorption performance for dyes and organic compounds, achieving a removal rate of over 85% for methylene blue (MB) dye. The optimal adsorption performance is achieved with a 1.6 mg modified graphite adsorbent at 60 °C under alkaline conditions for adsorbing 10 ppm MB. Adsorption kinetics and isotherm models were applied to elucidate the adsorption mechanisms. The results fit the Langmuir model, suggesting that monolayer homogeneous adsorption is favorable. Importantly, the results demonstrate that high-temperature treatment can significantly enhance the adsorption properties of coal-based graphite, supporting its application in dyeing wastewater treatment. Full article

Gasification technology enables the clean and efficient utilization of coal. However, the process generates a significant amount of solid waste—coal gasification slag. This paper focuses on the Jinhua furnace coal gasification slag (fine slag, FS; coarse slag, CS) as the research subject, analyzing its composition and structural characteristics, and discussing the thermochemical conversion performance of both under different atmospheres (N₂ and air). The results show that the fixed carbon content in FS is as high as 35.82%, while it is only 1% in CS. FS has a large number of fluffy porous carbon on its surface, which wraps around or embeds into smooth and variously sized spherical inorganic components, with a specific surface area as high as 353 m²/g, and the pore structure is mainly mesoporous. Compared to the raw coal (TYC), the types of organic functional groups in FS and CS are significantly reduced, and the graphitization degree of the carbon elements in FS is higher. The ash in FS is mainly amorphous and glassy, while in CS, it mainly has crystalline structures. The weight loss rates of TYC and FS under an inert atmosphere are 27.49% and 10.38%, respectively; under an air atmosphere, the weight loss rates of TYC and FS are 81.69% and 44.40%, respectively. Based on the analysis of the thermal stability of FS and its high specific surface area, this paper suggests that FS can be used to prepare high-value-added products such as porous carbon or high-temperature-resistant carbon materials through the method of carbon–ash separation. Full article

Carbon-based composite materials, denoted as C/C composites and possessing high thermal conductivity, were synthesized utilizing a three-dimensional (3D) preform methodology. This involved the orthogonal weaving of mesophase pitch-based fibers in an X (Y) direction derived from low-temperature carbonization, and commercial PAN-based carbon fibers in a Z direction. The 3D preforms were saturated with mesophase pitch in their raw state through a hot-pressing process, which was executed under relatively low pressure at a predetermined temperature. Further densification was achieved by successive stages of mesophase pitch impregnation (MPI), followed by impregnation with coal pitch under high pressure (IPI). The microstructure and thermal conductivity of the C/C composites were systematically examined using a suite of analytical techniques, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and PLM, amongst others. The findings suggest that the volumetric fraction of fibers and the directional alignment of the mesophase pitch molecules can be enhanced via hot pressing. The high graphitization degree of the mesophase pitch matrix results in an increased microcrystalline size and thus improved thermal conductivity of the C/C composite. Conversely, the orientation of the medium-temperature coal pitch matrix is relatively low, which compensates for the structural inadequacies of the composite material, albeit contributing minimally to the thermal conductivity of the resultant C/C composites. Following several stages of impregnation with mesophase pitch and subsequent impregnation with medium-temperature coal pitch, the 3D C/C composites yielded a density of 1.83 and 2.02 g/cm³. The thermal conductivity in the X (Y) direction was found to be 358 and 400 W/(m·K), respectively. Full article

In this study, changes in the microstructure of coal-tar pitch (CTP) during successive processes, including pyrolysis, polycondensation, and crystallization, were examined in connection with the resulting variations in structure factors, as measured by X-ray diffraction (XRD) analysis, and functional groups, as confirmed by Fourier transform infrared (FTIR) spectroscopy. To this end, four zones were defined based on variations in crystallinity, which were indicated by d₀₀₂ and L_c. Each zone was further characterized by interpreting crystallinity development in relation to changes in functional groups and specimen height. At around 400 °C, polycondensation occurred as the C-H_ar and C-H_al peaks decreased in intensity. These peak reductions coincided with the formation of mesophase spheres, resulting in enhanced crystallinity. Subsequently, at around 500 °C, the peak intensity of C-H and COOH decreased, which was attributed to the release of large amounts of gases. This led to sharp volume changes and a temporary reduction in crystallinity. All these results suggest that changes in the functional groups of CTP at lower temperatures (600 °C or less) during the carbonization process are closely associated with variations in its crystallinity. The major findings of the present study provide valuable insights for designing highly effective processes in the manufacturing of synthetic graphite blocks using CTP as a binder material, including by selecting appropriate temperature ranges to minimize volume expansion and crystallinity degradation and determining the lowest possible carbonization temperature to ensure adequate binder strength. Full article

China has ranked first worldwide in graphite imports in recent years, facing a graphite supply risk. Coal-hosted graphite is the focus of future graphite deposit exploration. The current research on the enrichment and mineralization mechanism of coal-hosted graphite is superficial, and the identification standard of coal-hosted graphite is incomprehensive, restricting the exploration of coal-hosted graphite mineral resources and the development of coal metamorphic evolution theory. In this study, the Caotangou–Meigoucoal-hosted graphite deposit in western Qinling Mountain was taken as a case study for dissection. Based on the data from 1/50,000 and 1/200,000 regional geological mapping and the data of graphite mines in the study area, the samples were systematically collected and analyzed to explore the mechanism of coal graphitization through a 1:5000 geological profile survey, 1/10,000 geological mapping in key areas, and the investigation and cataloguing of abandoned coal-hosted graphite adit. The result was that there were two main coal-hosted graphite ore bodies, striking from nearly east to west. The R_max values of the samples were 7.23–8.15%, the average values of V_daf were around 5.0%, the d₀₀₂ value of the II ore body was 0.3433–0.3389 nm, the d₀₀₂ value of the I ore body was mainly 0.3418–0.3429 nm, the graphitization degree G value of the II ore body was 8.14–59.30%, the graphitization degree G value of the II ore body was 12.79–25.58%. The II ore body was coal-hosted graphite, while some samples of the I ore body were coal-hosted graphite, and some samples were coal. The magmatic heat controls the thermal metamorphism of coal seams to form graphite. The closer the distance to the magma body, the larger the crystals, and the higher the euhedral degree, indicating the higher degree of coal seam metamorphism. The nearly north–south compressive structures mainly provided effective tectonic stress for the evolution of coal graphitization during the Yanshan period; the basic structural units (BSUs) rotated and rearranged, eventually forming a straight graphite structure, and tectonic stress catalyzed the graphitization process. The coal-hosted graphite deposits formed under the dual effects of magmatic heat transfer and tectonic stress. Full article

The challenge of how to effectively treat minerals in coal before synthetic graphitization is a practical problem. It is unrealistic to remove minerals completely via physical or chemical methods. So, it is essential to clarify the role of minerals in the synthetic graphitization of coal. Based on the complex mineral composition, the mixture samples consisting of coal and mineral are used to obtain the effect of minerals type and content on the synthetic graphitization of coal. The role of minerals in synthetic graphitization is closely associated with the mineral content and type, as well as the rank. As to the lower-rank anthracite, quartz, kaolinite, and calcite have the role of inhibitor for the yields and defect degrees of corresponding samples after synthetic graphitization derived from the mixtures, but the role of catalyzer for their crystal structure (the degree of graphitization, stacking height, lateral size). The increasing content of quartz, kaolinite, and calcite is harmful for the yield, but useful for the crystal structure and defect degrees; the increasing content of pyrite is harmful for the yield, degree of graphitization, and stacking height, and it is useful for defect degrees. As to the higher-rank anthracite, quartz, kaolinite, and calcite have the role of inhibitor for the yield of corresponding samples after synthetic graphitization, catalyzer for their crystal sizes (stacking height, lateral size), and inertia for their degrees of graphitization. The increasing content of quartz, kaolinite, calcite, and pyrite is harmful for the yield and crystal size. A lower coal rank indicates being more prone to positive mineral effects on synthetic graphitization. The role of minerals in the synthetic graphitization of coal is complex and also represents a coupling relationship with the thermal transformation of anthracite. Full article

Microwave-absorbing materials have attracted extensive attention due to the development of electronic countermeasures. In this study, novel nanocomposites with core–shell structures based on the core of Fe-Co nanocrystals and the shell of furan methylamine (FMA)-modified anthracite coal (Coal-F) were designed and fabricated. The Diels-Alder (D-A) reaction of Coal-F with FMA creates a large amount of aromatic lamellar structure. After the high-temperature treatment, the modified anthracite with a high degree of graphitization showed an excellent dielectric loss, and the addition of Fe and Co effectively enhanced the magnetic loss of the obtained nanocomposites. In addition, the obtained micro-morphologies proved the core–shell structure, which plays a significant role in strengthening the interface polarization. As a result, the combined effect of the multiple loss mechanism promoted a remarkable improvement in the absorption of incident electromagnetic waves. The carbonization temperatures were specifically studied through a setting control experiment, and 1200 °C was proved to be the optimum parameter to obtain the best dielectric loss and magnetic loss of the sample. The detecting results show that the 10 wt.% CFC-1200/paraffin wax sample with a thickness of 5 mm achieves a minimum reflection loss of −41.6 dB at a frequency of 6.25 GHz, indicating an excellent microwave absorption performance. Full article

Graphite can be artificially converted from anthracites under high temperatures; however, the exact mechanism through which inorganic minerals contribute to the graphitization process is still unknown. In light of this, several selected minerals in different amounts were added to demineralized anthracite coal. The anthracite–mineral mixtures were subjected to artificial graphitization experiments under temperatures ranging from 1700 to 2900 °C in the laboratory. The obtained series of coal-based graphites with various levels of graphitization were characterized by X-ray diffraction (XRD), and the derived structural parameters, such as d₀₀₂ and FWHM (002), La, and Lc were used to compare the carbon structural evolution during the high temperature treatment and mineral catalytic graphitization. Moreover, the amorphous carbon of anthracite is eventually transformed into the highly ordered crystalline carbon of coal-based graphite. The five added minerals show interesting structural variation during the graphitization process, in which pyrite is decomposed into iron (Fe), illite, quartz, and kaolinite, which can react with disordered carbon in organic matter to form moissanite (SiC), while dolomite seems to react with sulfur to form oldhamite (CaS). At temperatures less than 2300 °C, the minerals could significantly enhance the catalytic effect. There is a clear difference in the catalytic effect of different minerals on graphitization. Kaolinite exhibits the strongest catalytic effect. The minerals dolomite, illite, and quartz only show a certain degree of catalysis. Pyrite, however, only has a limited effect on improving the degree of graphitization at a temperature of 1700 °C. However, once the temperature exceeds 2300 °C, the dominant factor controlling the graphitization of anthracite appears to be the temperature. According to the growth pattern at microcrystalline sizes (La and Lc), the minerals’ catalytic effects can be classified into three groups. The first group includes minerals that preferentially promote La growth, such as pyrite, illite, and quartz. The second group includes minerals that preferentially promote Lc growth, such as dolomite. Finally, kaolinite is in a separate group that promotes microcrystal growth in both the lateral and vertical directions simultaneously. The mechanisms of the minerals’ catalytic graphitization are discussed in this paper. The promotion role of minerals in the artificial graphitization process may help to optimize the graphitization process and reduce the process cost in the future. Full article

Algae have the potential to be used as a feedstock for the synthesis of valuable compounds and biofuels. In addition, algal waste can be further transformed into biofuel, biogas, and biochar using different thermochemical processes such as microwave pyrolysis, pyrolysis, torrefaction, and hydrothermal conversion. Due to its high specific surface area, rapid electron transport, and graphitic carbon structure, algal biochar carbonized at high temperatures has shown outstanding performance for applications as CO₂ adsorbents, supercapacitors, and persulfate activation. Due to the combination of various functional groups and porous structures, the algae biomass pyrolysis at a moderate temperature produced high-quality biochar that shows high performance in terms of pollutant removal, while low-temperature pyrolysis produces coal fuel from algae via torrefaction. Over time, there have been exponentially more petroleum-based polymers created that have harmful impacts on both humans and the environment. As a result, researchers are becoming more interested in algae-based biopolymers as a potential alternative strategy for establishing a sustainable circular economy globally. The advantages of microalgal biopolymer over other feedstocks are its capacity to compost, which provides greenhouse gas credits, its quick growth ability with flexibility in a variety of settings, and its ability to minimize greenhouse gas emissions. Full article

Coal is a carrier of carbon enrichment, so it has the potential for the preparation of coal-based carbon materials. In this paper, LT anthracite and TSG bituminous coal were selected, and the corresponding graphitized samples were prepared from high-temperature treatment. The effects of silicon-containing minerals on coal evolution during the high-temperature pre-graphitization stage were investigated by XRD, Raman spectroscopy, and SEM. The results showed that with increasing temperature, the silicon-containing samples showed smaller d₀₀₂ and ID₁/IG, and higher L_c, while L_a presented a slight increase. It was found by SEM that the micromorphology of all samples was mainly massive structures. Meanwhile, irregular polyhedral structures also were observed in silicon-containing samples at 1300 °C, which were related to the formation and deposition of SiC. The carbothermal reactions of silicon-containing minerals continued to generate SiC and precipitate with increasing temperature, resulting in the gradual transformation of the needle-like structures into polyhedral structures. However, SiC was completely decomposed at 2800 °C. These changes indicated that during the pre-graphitization stage, silicon-containing minerals form SiC to advance the reduction of the interlayer spacing and the increase of longitudinal layer stacking height, thereby enhancing structural ordering and graphitization degree, while it had less effect on the lateral size. This will help to further understand the role of silicon-containing minerals in the coal pre-graphitization stage and also provide useful information about synthetic coal-based graphite. Full article