• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.515-521
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• 2023

In this study, waste carbon fiber obtained by pyrolysis of carbon fiber reinforced plastic (CFRP) was used to produce carbon fluoride through vapor phase fluorination and recycled as a reducing electrode material for lithium primary batteries. First, the physicochemical properties of the waste carbon fiber obtained by pyrolysis were determined, and the structural and chemical properties of carbon fluoride were analyzed to evaluate the effect of vapor phase fluorination on the waste carbon fiber. XRD analysis confirmed that the hexagonal network carbon laminated structure (002 peak) of the waste carbon fiber was gradually converted into a carbon fluoride structure (CF_X, 001 peak) as the temperature of gas phase fluorination increased. The discharge capacity of the lithium primary battery produced using this carbon fluoride was up to 862 mAh/g. This was compared to the discharge capacity of carbon fluoride-based Li-ion batteries made of other carbon materials. These results suggest that carbon fluoride made from waste CFRP-based carbon fibers can be used as a reducing electrode material for Li-ion batteries.

• The Journal of Engineering Research
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• v.4 no.1
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• pp.93-107
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• 2002

The active carbon waste which was used in water purification plant was investigated for the improvement of capillary after microwave treatment. The variation of surface area was measured with the various kinds and amounts of active carbon. The water vapor as the activator was verified to improve the capillary but it reacted with the water contained in waste active carbon. In contrast to the water vapor, the $CO_2$ gas improved the surface area about 10-20 % compared to as received one. The best results was observed at the intensity of 2.75 kw microwave. The more effective recovery of active carbon waste was observed at the microwave treatment compared to the rotary kiln treatment. However, the mass production is so difficult in the microwave process.

• Journal of the Korean Ceramic Society
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• v.43 no.5 s.288
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• pp.315-319
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• 2006

There have been some studies on the use of coal waste as a raw material for clay bricks due to the lack of naturally producing minerals. It can help resolving the problems of pollution, forest conservation and flood control by utilizing coal waste. However, high content of carbon materials usually leads to the black core in clay bricks after firing process, and diminishes the mechanical and aesthetical properties of clay brick. In this study, the effect of firing process is investigated for the removal of black core in clay bricks with carbon content. The removal kinetics of black core are also compared and investigated with the firing schedule and black core removal.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.317-324
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• 2013

This research assessed the surface properties of modified activated carbons with three different acids and five different metals for ammonia gas removal. Raw bituminous coal-based activated carbon ($4{\times}8$ mesh) had low adsorption capacity of 0.72 mg $NH_3/g$ based on the analysis in the column adsorption experiment. Adsorption capacities of carbons modified with $CH_3COOH$, $H_3PO_4$, and $H_2SO_4$ increased up to 3.34, 21.00, and 35.21 mg $NH_3/g$, respectively. Those of carbons with Cu, Zn, Zr, Fe, and Sn were 9.63, 9.13, 7.09, 25.12 and 15.03 mg $NH_3/g$. Ammonia adsorption was enhanced by the presence of surface oxygen groups on carbon materials, which influenced pH of carbon surface. BET surface area of raw carbon was analyzed to be $1087m^2/g$, but it decreased by carbon surface modification. Fe-impregnated carbon showed $503.02m^2/g$ of surface area. These observations were mostly caused by chemical adsorption.

• Korean Journal of Materials Research
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• v.15 no.3
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• pp.177-182
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• 2005

Large amounts of the waste SiC sludge containing small amounts of Si and organic lubricant were produced during the wire cutting process of the single silicon crystal ingots. The waste SiC sludge was purified by the washing process and the purified SiC powders were used to fabricate continuously porous $SiC-Si_3N_4$ composites using a fibrous monolithic process, in which carbon, $6wt\%\;Y_2O_3-2\;wt\%\;A1_2O_3$ and ethylene vinyl acetate were added as a pore-forming agent, sintering additives, and binder, respectively. In the burning-out process, carbon was fully removed and continuously porous $SiC-Si_3N_4$ composites were successfully fabricated. The green bodies containing SiC, Si particles and sintering additives were nitrided at $1410^{\circ}C$ in a flowing $N_2+10\%\;H_2$ gas mixture. Continuously porous composites were combined with SiC, ${\alpha}Si_3N_4,\;\beta-Si_3N_4$ and a few $\%$ of Fe phases. The pore size of the 2nd and the 3rd passed $SiC-Si_3N_4$ composites was $260\;{\mu}m$ and $35\;{\mu}m$ in diameter, respectively.

• Resources Recycling
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• v.33 no.4
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• pp.29-35
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• 2024

The recycling of waste resources, such as spent catalysts, primarily involves leaching and extracting metal components via smelting. These metal components are then recovered as salts, such as sulfates and nitrates. When crystallization occurs during the calcination of the recovered salts, the salts are converted into oxides, which are then reduced to form metals or ceramic materials. Common reducing agents used in oxide reduction include hydrogen and carbon, and metal powders are obtained upon reduction. Carbide synthesis can occur if the recycled element is a transition metal and carbon is used as the reducing agent. Despite being ceramic materials, transition metal carbides exhibit excellent conductivity owing to their metallic bonding. Recently, MXene, a two-dimensional transition metal carbide, has gained attention for electromagnetic wave shielding, secondary battery electrodes, and water purification owing to its electrical conductivity and large surface area. This study developed a process for synthesizing high-value MXene materials from waste resources. The properties of these MXenes were evaluated to confirm the potential of using waste resources as raw materials for MXenes.

• Advances in materials Research
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• v.13 no.3
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• pp.221-232
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• 2024

Waste tire management and recycling have grown to be significant issues because they bring up a global environmental concern. Thus, turning recycled waste tires into useful products may help tackle the environmental issue. This research aims to study and compare the effect of recycled carbon black (rCB) and commercial carbon black (CB) at certain 15 vol. % of filler loading on the mechanical, thermal, morphology and electrical properties of epoxy/CB composites. For this project, epoxy resin, diethyltoluenediamine (DETDA), recovered carbon black (rCB) and commercial carbon black (CB) graded N330, N550, N660 and N774 were mixed and compared accordingly to the formulation determined. The CB content was dispersed in the epoxy matrix using the mechanical mixing technique. The distribution and dispersion of CB in the epoxy matrix affect the characteristics of the conductive composites. rCB content at 15 vol% was selected at fixed content for comparison purposes due to the optimum value in electrical conductivity results. The flexural strength results followed the sequence of rCB>N774>N660>N550>N330. As for electrical conductivity results, epoxy/N330 exhibited the highest conductivity value, while the others achieved a magnitude of X10^-3 due to the highest external surface area of N330. In terms of thermal stability, epoxy/N330 and epoxy/N774 were slightly more stable than epoxy/rCB.

• Composites Research
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• v.35 no.4
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• pp.242-247
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• 2022

This study has a different direction from the existing technology of applying recycled carbon fiber obtained by recycling waste CFRP to CFRP again. A study was conducted to utilize recycled carbon fiber as a raw material for manufacturing a carbon/carbon (C/C) composite material comprising carbon as a matrix. First, it was attempted to recycle a commonly used epoxy resin composite material through a thermal decomposition process. By applying the newly proposed oxidation-inert atmosphere conversion technology to the pyrolysis process, the residual carbon rate of 1~2% was improved to 19%. Through this, the possibility of manufacturing C/C composite materials utilizing epoxy resin was confirmed. However, in the case of carbon obtained by the oxidation-inert atmosphere controlled pyrolysis process, the degree of oxygen bonding is high, so further improvement studies are needed. In addition, short-fiber C/C composite material specimens were prepared through the crushing and disintegrating processes after thermal decomposition of waste CFRP, and the optimum process conditions were derived through the evaluation of mechanical properties.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.147-152
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• 2004

In Sequence Batch Reactor (SBR), the removal efficiencies if nutrient materials such as nitrogen and phosphate depend highly on quantity and quality of organic carbon source. Food waste thai contains abundant organic materials has been produced in ship. The applicability if anaerobically fermented if food waste (AFFW) as an external carbon source was examined in the lab-scale SBR process operated at $25^{\circ}C$. With the addition if AFFW increased, average removal efficiencies if $COD_cr$, T-N, T-P changed to $98.5\%,\;95\%,\;93\%$, respectively. Denitrification rate is 0.30g $NO_3-N/g\;VSS{\cdot}day$. In summary, it was suggested tint AFFW sould be used as an economical and effective carbon source for the biological nitrogen and phosphate removal.

• Carbon letters
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• v.16 no.1
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• pp.11-18
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• 2015

The process of oxidizing polyacrylonitrile (PAN)-based carbon fibers converts them into an infusible and non-flammable state prior to carbonization. This represents one of the most important stages in determining the mechanical properties of the final carbon fibers, but the most commonly used methods, such as thermal treatment ($200^{\circ}C$ to $300^{\circ}C$), tend to waste a great deal of process time, money, and energy. There is therefore a need to develop more advanced oxidation methods for PAN precursor fibers. In this review, we assess the viability of electron beam, gamma-ray, ultra-violet, and plasma treatments with a view to advancing these areas of research and their industrial application.