간행물

Carbon Letters KCI 등재 Carbon letters

권호리스트/논문검색
이 간행물 논문 검색

권호

Vol.31 No.6 (2021년 12월) 24건

1.
2021.12 구독 인증기관 무료, 개인회원 유료
Thermal reduction of graphite oxide in the presence of nitrogen‑containing dyes
Jurgis Barkauskas, Justina Gaidukevič, Gediminas Niaura
Carbon Letters Vol.31 No.6 pp.1097-1110 한국탄소학회
Thermal reduction of graphite oxide (GO) is considered as a prospective method for the preparation of high-performance graphene-based materials. However, this method has certain limitations, and the major is that this exothermic process is difficult to control. In this research, we focused on the kinetic studies of the reduction of graphite oxide using non-isothermal differential calorimetry (DSC) method. Six GO nanocomposites with dyes were tested to study the shift in kinetic parameters. The apparent reaction order is determined to be ca 0.7 for the thermal decomposition of pure GO, while in the presence of dye molecules it increases sometimes reaching a value of 2.0 for higher dye concentrations. Decisively, the thermal decomposition of pure GO can be presented as an intermediate between a zero- and first-order reaction, while the introduction of dye molecules turns a certain part of the energy consumption via the bimolecular pathway. Our research revealed that the process of GO thermal decomposition can be operated and properties of the final product (reduced graphene oxide (rGO) and its derivatives) can be adjusted more precisely using additive molecules, which interact with GO sheets.
4,600원
2.
2021.12 구독 인증기관 무료, 개인회원 유료
Performance evaluation of Al6061‑graphene nanocomposites surface engineered by a novel multiple microchannel reinforcement approach in friction stir processing
Abhishek Sharma, Tanmoy Das, Jinu Paul
Carbon Letters Vol.31 No.6 pp.1111-1124 한국탄소학회
In this paper, the performance evaluation of Al-graphene nanoplatelets (GNP) composites surface engineered by a modified friction stir processing (FSP) is reported. Here, multiple micro channels (MCRF) are used to incorporate GNPs in the aluminium matrix instead of a single large groove (SCRF) that is usually used in conventional FSP. With the MCRF approach, ~ 18% higher peak temperature (compared to SCRF) was observed owing to the presence of aluminium sandwiched between consecutive microgrooves and higher heat accumulation in the stir zone. The MCRF approach have significantly reduced the coefficient of friction and wear rates of the processed composites by ~ 14% and ~ 57%, respectively as compared to the SCRF approach. The proposed reinforcement filling method significantly improves the particle dispersion in the matrix, which in turn changes the adhesion mode of wear in SCRF to abrasive mode in MCRF fabricated composites. The uniformly squeezed out GNP tribolayer prevented the direct metal to metal contact between composite and its counterpart which have effectively reduced the deterioration rates.
4,600원
3.
2021.12 구독 인증기관 무료, 개인회원 유료
A new insight into the structural modulation of graphene oxide upon chemical reduction probed by Raman spectroscopy and X‑ray diffraction
Neakanshika Chadha, Rahul Sharma, Parveen Saini
Carbon Letters Vol.31 No.6 pp.1125-1131 한국탄소학회
Lately, Raman spectroscopy has become powerful tool for quality assessment of graphene analogues with identification of intensity ratio of Raman active D-band and G-band ( ID/IG ratio) as a vital parameter for quantification of defects. However, during chemical reduction of graphitic oxide (GrO) to reduced GrO (RGrO), the increased ID/ IG ratio is often wrongly recognized as defect augmentation, with “formation of more numerous yet smaller size sp2 domains” as its explanation. Herein, by giving due attention to normalized peak height, full-width half-maxima and integrated peak area of Raman D- and G-bands, and compliment the findings by XRD data, we have shown that in-plane size of sp2 domains actually increases upon chemical reduction. Particularly, contrary to increased ID/ IG ratio, the calculated decrease in integrated peak area ratio ( AD/AG ratio) in conjunction with narrowing of D-band and broadening of G-band, evinced the decrease in in-plane defects. Finally, as duly supported by reduction induced broadening of interlayer-spacing characteristic XRD peak and narrowing of ~ 43° centered XRD hump, we have also shown that the sp2 domains actually expands in size and the observed increase in ID/ IG ratio is indeed due to increase in across-plane defects, formed via along-the-layer slicing of graphitic domains.
4,000원
4.
2021.12 구독 인증기관 무료, 개인회원 유료
Biomass‑derived porous activated carbon nanofibers from Sapindus trifoliatus nut shells for high‑performance symmetric supercapacitor applications
Murugan Vinayagam, Rajendran Suresh Babu, Arumugam Sivasamy, Ana Lucia Ferreira de Barros
Carbon Letters Vol.31 No.6 pp.1133-1143 한국탄소학회
Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/ g), large pore volume (0.212 cm3 g− 1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g− 1 with current density of 0.2 A g− 1 and it is maintained to 65.6 F g− 1 at high current density of 2.0 A g− 1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg− 1 at 400 W kg− 1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.
4,200원
5.
2021.12 구독 인증기관 무료, 개인회원 유료
Promising nature‑based activated carbon derived from flowers of Borassus flabellifer for supercapacitor applications
Zaharaddeen S. Iro, C. Subramani, Jerome Rajendran, Ashok K. Sundramoorthy
Carbon Letters Vol.31 No.6 pp.1145-1153 한국탄소학회
Recently, activated carbon derived from different agricultural by-products or bio-waste is receiving a great deal of attention due to its low or zero cost and environmental friendliness. In this work, flowers obtained from Borassus flabellifer (BFL) is used as a carbon source and potassium hydroxide (KOH) as activation precursor to produce activated carbon with high specific surface area and predominant micropore. The obtained carbon material was activated at 650 °C. The as-prepared sample had a specific surface area of 930.3 m2/ g and pore size distribution of 1.96 nm. The carbon material exhibited high electrochemical performance with a specific capacitance of 247 F/g at 0.5 A/g in 1 M H2SO4 electrolyte and an excellent cycling stability of 94% after 2500 cycles. A specific energy of 101.1 Wh/kg and a specific power of 4500 kW/kg were obtained. Based on the electrochemical properties exhibited by BFL, it could be used as an excellent electrode material for supercapacitor applications.
4,000원
6.
2021.12 구독 인증기관 무료, 개인회원 유료
Synthesis of γ‑carboline derivatives via indole‑2,3‑dienolate
Gopi Reddy Alugubelli, Sivanadh Musunuri, Reddymasu Sreenivasulu, Mandava Venkata Basaveswara Rao
Carbon Letters Vol.31 No.6 pp.1155-1161 한국탄소학회
Anion assisted [4 + 2] cycloaddition reaction via indolo[2,3]-dienolate by reacting 1,2-dimethylindole-3-carboxaldehyde with aromatic nitriles using lithium diisopropylamide in terahydrofuran, a facile and convenient regiospecific route designed and developed for the synthesis of γ-carbolines.
4,000원
7.
2021.12 구독 인증기관 무료, 개인회원 유료
Effective removal of arsenide from aqueous solutions using mesoporous CoFe2O4/ graphene oxide nanocomposites assisted by artificial intelligence
Xianliang Wu, Jiwei Hu, Xingfu Wang, Ling Xin, Caifang Li, Xionghui Wei
Carbon Letters Vol.31 No.6 pp.1163-1178 한국탄소학회
This study investigated the arsenide removal by using mesoporous CoFe2O4/ graphene oxide nanocomposites based on batch experiments optimized by artificial intelligence tools. These nanocomposites were prepared by immobilizing cobalt ferrite on graphene oxide and then characterized using various techniques, including small angle X-ray diffraction, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. Artificial intelligence tools associated with response surface methodology were employed to optimize the conditions of the arsenide removal process. The results showed that back propagation neural network combined with genetic algorithm was suitable for the arsenide removal from aqueous solutions by the nanocomposites based on the minimum average values of absolute errors and the value of R2. The optimal values of the four variables (operating temperature, initial pH, initial arsenide concentration, and contact time) were found to be 25.66 °C, 7.58, 10.78 mg/L and 46.41 min, and the predicted arsenide removal percentage was 84.78%. The verification experiment showed that the arsenide removal percentage was 86.62%, which was close to the predicted value. Three evaluation methods (gradient boosted regression trees, Garson method and analysis of variance) all demonstrated that the temperature was the most important explanatory variable for the arsenide removal. In addition, the arsenide removal process can be depicted with pseudo-second-order kinetics model and Langmuir isotherm, respectively. The thermodynamics investigation disclosed that the adsorption process was of a spontaneously endothermic nature. In summary, this study showed that ANN-GA was an efficient and feasible method in determining the optimum conditions for arsenic removal by CoFe2O4/ graphene oxide nanocomposites.
4,900원
8.
2021.12 구독 인증기관 무료, 개인회원 유료
Study of the ageing mechanisms of activated carbon supercapacitors by electrothermal simulation and experimental analysis
Amine Erradi, Samira Touhtouh, Abdessamad El Ballouti, Abdelowahed Hajjaji
Carbon Letters Vol.31 No.6 pp.1179-1189 한국탄소학회
In view of the growing need for clean energy, supercapacitors (SC), especially those based on activated carbon (AC) and organic electrolyte are attracting great attention for their theoretically infinite life span. However, they still age much faster than expected due to certain mechanisms. Several researches is being conducted to understand these mechanisms, but so far, the chemical reactions at the phase boundary of the activated carbon electrodes and organic electrolyte have been very unclear. Some pathways have not yet been investigated; there is no research on the reactions that can take place between acetonitrile in the vapor phase and the oxides presented on the surface of activated carbons. For this reason, in this study, divided into two parts, the first based on a thermal simulation and the second based on an experimental study, we have systematically described the ageing mechanisms by determining the gas-phase reactions that can occur at the electrode–electrolyte interface. On the one hand, a thermal model of a supercapacitor cell using activated carbon and organic electrolyte technology has been developed. This model allowed us to study the temperature distribution of supercapacitors, and thus to determine the thermodynamic parameters related to the phenomena produced at the electrode–electrolyte interface. On the other hand, a thermo-gravimetric analysis coupled with gas phase infrared spectroscopy on the activated carbons of an aged supercapacitor of the same technology as that used in the simulation was carried out. The results obtained made it possible to identify the chemical groups produced by ageing.
4,200원
9.
2021.12 구독 인증기관 무료, 개인회원 유료
Raw and pyrolyzed (with and without melamine) graphene nanoplatelets with different surface areas as PEM fuel cell catalyst supports
Ayşenur Öztürk, Ayşe Bayrakçeken Yurtcan
Carbon Letters Vol.31 No.6 pp.1191-1214 한국탄소학회
Platinum (Pt) catalysts dispersed on carbon-based support materials are generally used in the polymer electrolyte membrane (PEM) fuel cells. In this study, commercial graphene nanoplatelets (GNPs), with different surface areas (320, 530, 800 m2 g− 1), were used as catalyst supports in PEM fuel cells. These GNPs were also pyrolyzed under the inert atmosphere, with and without melamine, as the nitrogen (N) source. Various characterizations (Elemental analysis, FTIR, Raman spectroscopy, BET, TEM, HRTEM, SAED, XRD, TGA, ICP-MS, contact angle measurement, CV, ORR, chronoamperometry, EIS, PEM fuel cell performance test) were performed for the detailed analysis of Pt/GNPs. Based on the three-electrode cell system, the lowest electrochemical surface area (ECSA) loss (29.9%), Pt mass activity loss (20.3%) and overall (charge and mass) resistance (42.2 Ω) were obtained with the Pt/M-530 catalyst. According to the in-situ PEM fuel cell performance results, the specific peak power density was recorded as (450 mW mg Pt− 1) for the Pt/R-530 catalyst, which has also the second most hydrophobic catalyst layer surface with the 146.5° ± 1.28° contact angle value. On the heels of Pt/R-530, the two best performances also belong to the Pt/M-530 (391 mW mg Pt− 1) and Pt/P-530 (378 mW mg Pt− 1) catalysts of the same group.
6,100원
10.
2021.12 구독 인증기관 무료, 개인회원 유료
Cost effective biosynthetic approach for graphene exhibiting superior sonochemical dye removal capacity
Syed Akhil, Al Musawi Mahdi Jawad Saeed, Syam Sundar Majety, Bhanu Mullamuri, Ganesh Majji, Debasrita Bharatiya, Venkata Sai Sriram Mosali, Hari Babu Bollikolla, Basavaiah Chandu
Carbon Letters Vol.31 No.6 pp.1215-1225 한국탄소학회
Green synthesis of graphene using leaf extracts as sustainable reducing and capping agents is a thrust area of research owing to its simplicity, eco-friendly nature and the ease of access to graphene. Moringa (Moringa oleifera Lam) plant is widely cultivated in India owing to its important medicinal and nutritional values. Inspired by these reports, herein we report a simple, green and economic synthesis of graphene, Moringa leaf extract employed reduced graphene oxide (MRGO) with excellent dye removal efficiencies. The MRGO is prepared by refluxing a mixture of aqueous dispersion of graphene oxide and Moringa leaf extract for 10 h. Further, we elucidated the role of synthesized MRGO in the removal of methylene blue (MB) and rhodamine B (RB) dyes through the sonochemical method. This as-synthesized material exhibited excellent dye removal efficiencies of about 93% and 87% against MB and RB dyes, respectively. Graphene with huge surface area expedited the better adsorption of dye molecules, thus, facilitated the better removal of the latter. Therefore, the superior dye removal efficiencies of MRGO were attributed to its adsorption capacity. This cost-effective synthetic approach of MRGO nanomaterial has a great potential for the innovative applications in water purification technology and find its place in further industrialization.
4,200원
11.
2021.12 구독 인증기관 무료, 개인회원 유료
Predicting an ideal 2D carbon nanostructure with negative Poisson’s ratio from first principles: implications for nanomechanical devices
Kun Yuan, Yaoxiao Zhao, Mengyang Li, Yanzhi Liu
Carbon Letters Vol.31 No.6 pp.1227-1235 한국탄소학회
The intrinsic negative Poisson’s ratio effect at the level of molecule in two-dimensional nanomaterials, especially in the perfect planar nanostructures with a single atom thickness, is really rare and has attracted a lot of research interests because of its unique mechanical properties in the nanoscale and extensive applications in mechanical nanodevices. In this work, a novel ideal planar carbon nanostructure (PCNS) framework with a single atom thickness composed by carbon and hydrogen atoms is proposed and studied by means of first-principles density functional calculation. The results showed that the PCNS is, simultaneously, of excellent thermodynamic, molecular dynamic and mechanical stabilities. In addition, the electronic structure, mechanical characters, and optical-electronic characteristics of PCNS are also explored. Excitedly, it is found that the PCNS has a significant negative Poisson’s ratio effect in plane, and the maximum value of Poisson’s ratio is as high as − 2.094. Meanwhile, the material has a wide range of elastic mechanics. Moreover, the PCNS presents an ideal UV absorption performance. It is hoped that this work could be a useful structural design strategy for the development of the ideal 2D carbon-based nanomechanical devices with the intrinsic negative Poisson’s ratio effect and other electronic functions.
4,000원
12.
2021.12 구독 인증기관 무료, 개인회원 유료
An investigation on development of a molecular imprinted sensor with graphitic carbon nitride (g‑C3N4) quantum dots for detection of acetaminophen
Hilal Medetalibeyoğlu
Carbon Letters Vol.31 No.6 pp.1237-1248 한국탄소학회
In the present study, a novel electrochemical sensor for acetaminophen (AMP) which included quantum graphitic carbon nitride dots, g-C3N4QDs, was designed and conducted with molecular imprinted polymer (MIP). First, bulk g-C3N4 was generated with direct thermal polycondensation of melamine. After the treatment of the acidic solution containing H2SO4: HNO3 (1:1, v:v), the heating treatment at 200 °C on the dispersion provided g-C3N4QDs. In this respect, for nanomaterial characterization, some spectroscopic approaches were performed including Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) as well as electroanalytical methods such as electrochemical impedance (EIS) and cyclic voltammetry (CV). In accordance with the aims of the study, AMP imprinted electrode was formed after high electrocatalytic performance and linear range of 1.0 × 10– 11–2.0 × 10– 8 M and the LODs of 2.0 × 10– 12 was achieved. Eventually, an AMP-printed sensor was also used for AMP identification in pharmaceutical samples.
4,300원
13.
2021.12 구독 인증기관 무료, 개인회원 유료
Nitrogen‑doped and hierarchically porous carbon derived from spent coffee ground for efficient adsorption of organic dyes
Zhong Dai, Peng‑Gang Ren, Hua Zhang, Xin Gao, Yan‑Ling Jin
Carbon Letters Vol.31 No.6 pp.1249-1260 한국탄소학회
Here, a novel nitrogen-doped carbon nano-material (N-CGNM) with hierarchically porous structure was prepared from spent coffee ground for efficient adsorption of organic dyes by a simple one-step carbonization process (the uniform mixture consists of spent coffee ground, urea, and CaCl2 with the ratio of 1:1:1, which was heated to 1000 °C with a rate of 10 °C min− 1 and held at 1000 °C for 90 min in N2 atmosphere to carry out carbonization, activation, and N-doping concurrently). The morphology and structure analysis show that the prepared N-CGNM exhibits hierarchical pore structure, high specific surface area (544 m2/ g), and large numbers of positively charged nitrogen-containing groups. This unique structure and chemical composition endow N-CGNM with an excellent adsorption capacity toward anion Congo red (623.12 ± 21.69 mg/g), which is obviously superior to that (216.47 ± 18.43 mg/g) of untreated spent coffee ground-based carbon nano-materials (CGM). Oppositely, the adsorption capacity of N-CGNM towards cation methylene blue is inferior to that of CGM due to the existence of electrostatic repulsion. These findings show a great guidance for the development of low-cost but efficient selective adsorbent.
4,300원
14.
2021.12 구독 인증기관 무료, 개인회원 유료
CO2 capture using activated carbon synthesized from date stone: breakthrough, equilibrium, and mass‑transfer zone
Mohd Danish, Vijay Parthasarthy, Mohammed K. Al Mesfer
Carbon Letters Vol.31 No.6 pp.1261-1272 한국탄소학회
Global warming and climate changes are the ultimate consequences of increased CO2 volume in the air. Physical activation was used to prepare high-throughput activated carbon from a low-cost date stone. The adsorption performance of activated carbon using fixed bed for CO2 separation was studied. The reliance of temperature, flow rate, and initial CO2 concentration levels on breakthrough behaviour was analysed. The adsorption response was explored in terms of breakthrough and saturation points, adsorption capacity, temperature profiles, utilization factor, and length of mass-transfer zone. Increased temperatures lead to vary the breakthrough periods notably. The vastly steep breakthrough curves reveal satisfactory utilization of bed capacity. LMTZ is varied positively with increased feed rates and temperatures. The high utilization factor of 0.9738 with 1.66 mmol/g CO2 uptake was acquired at 298 K and 0.25 bars. The findings recommend that the carbon prepared from date stone is encouraging to capture CO2 from CO2/ N2 mixture.
4,300원
15.
2021.12 구독 인증기관 무료, 개인회원 유료
Facile synthesis of silver nanoparticle‑decorated zinc oxide nanocomposite‑based pencil graphite electrode for selective electrochemical determination of nitrite
Shridevi Salagare, Prashanth S. Adarakatti, Venkataramanappa Yarradoddappa
Carbon Letters Vol.31 No.6 pp.1273-1286 한국탄소학회
This work describes the facile synthesis of silver nanoparticle-decorated zinc oxide nanocomposite through a simple glycol reduction method. The silver nanoparticle-decorated zinc oxide nanocomposite-based pencil graphite electrode has been validated as a perceptive electrochemical sensing podium towards nitrite. The morphology of the prepared nanocomposite has been characterized via specific spectroscopic and electrochemical techniques. The sensor exhibits a notable enhancement in the cyclic voltammetric response to nitrite oxidation at an ideal peak potential of 0.76 V in pH 6.0 acetate buffer. Under optimum conditions of nitrite directly expanded with their concentration in the range from 30 to 1400 μM with a detection limit of 14 μM.
4,600원
16.
2021.12 구독 인증기관 무료, 개인회원 유료
Effect of solvent exchange on the properties of carbon xerogel and carbon xerogel/polypyrrole composites for supercapacitors
Meryem Samancı, Elif Daş, Ayşe Bayrakçeken Yurtcan
Carbon Letters Vol.31 No.6 pp.1287-1308 한국탄소학회
Carbon xerogels (CXs) with three-dimensional (3D) structure, unusual surface, physical, electrical and mechanical properties and their electrically conductive polymer polypyrrole (PPy) composites were synthesized as electrode materials for supercapacitors. The effect of different resorcinol/formaldehyde (R/C) ratios, whether solvent exchange with or without acetone and polypyrrole addition on the physicochemical (FTIR, XRD, BET, SEM and TGA) and electrochemical properties (CV, 1000 cycles) of the synthesized materials were investigated. It was observed that the R/C ratio and the solvent exchange process prior to drying affect the specific surface areas and the pore size distributions, thereby positively affecting the specific capacitance. PPy film thickness was observed to be effective in the specific capacitance of the electrode in PPy composite synthesis. Among the synthesized materials, the highest specific capacitance values belong to polypyrrole/carbon xerogel composites. As a result of the analysis and calculations, it was found that the highest specific capacitance belongs to CX2/PPy composite with 599 Fg− 1 at 5 mVs− 1. CX2/PPy composite has been found to have a capacitance retention rate of 80.30% at the end of 1000 cycles.
5,800원
17.
2021.12 구독 인증기관 무료, 개인회원 유료
Heteroatom‑doped mesoporous carbon prepared from a covalent organic framework/α‑MnO2 composite for high‑performance supercapacitor
Stella Vargheese, Dhanaprabhu Pattappan, K. V. Kavya, M. S. Sivaramkumar, Ramasamy Thangavelu Rajendra Kumar, Yuvaraj Haldorai
Carbon Letters Vol.31 No.6 pp.1309-1316 한국탄소학회
In this report, we successfully prepared nitrogen-doped porous carbon (N-PC)/manganese dioxide ( MnO2) composite for a high-performance supercapacitor. X-ray diffraction data revealed the α-MnO2 phase. Transmission electron microscopy confirmed that the nanostructured α-MnO2 nanoparticles were coated on the surface of N-PC. The N-PC/α-MnO2 composite delivered a capacitance of 525.7 F g− 1 at the charging current of 1.0 A g− 1. The higher capacitance of the composite could be owing to the synergy of MnO2 and N-PC. Besides, the electrode exhibited a 14.7% capacitance loss after 6000 charge– discharge cycles at 10 A g− 1 indicating good electrochemical stability.
4,000원
18.
2021.12 구독 인증기관 무료, 개인회원 유료
Analysis of pore formation and development in carbon blacks activated in a CO2 gas atmosphere through microstructural observation
Sang‑Min Lee, Sang‑Hye Lee, Suk‑Hwan Kim, Jae‑Seung Roh
Carbon Letters Vol.31 No.6 pp.1317-1326 한국탄소학회
The present study analyzed the pore formation and development process in carbon black that was activated by CO2 gas and the effect of the burn-off (BO) ratio on the process, particularly based on changes in the surface shape and internal microstructure. The activation process was performed as follows. Carbon blacks were injected into a horizontal tube furnace when the inside temperature reached 1000 °C. Carbon black samples with different BOs, i.e., 7.2%, 15.4%, 30.4%, 48.2%, 59.9%, and 83.2%, were prepared by varying the activation time. The microstructure of the activated samples was observed and examined using SEM and TEM. The results showed that pore passages were first created on the surface of the primary particles of the carbon black, and then the inner portion of the carbon black with a lower degree of crystallinity started to be activated, thereby causing inner pores to be formed. These inner pores then started to grow and coalesce into larger pores, thereby causing the crystallite layers in the inner portion of the carbon black to be activated. The changes in the microstructure of the carbon black during the activation reaction were attributable to the carbon black manufacturing process, in which the nucleation and growth of the primary particles of the carbon black occurred within a very short period of time. Thus, the crystallization of the inner portion was suppressed, and therefore, the degree of crystallinity was lower in the inner portion than in the outer portion.
4,000원
19.
2021.12 구독 인증기관 무료, 개인회원 유료
Evaluation of carbon nanotubes dispersion in aqueous solution with various dispersing agents
Youn Kim, Ji Soo Hong, Su Young Moon, Jin‑Yong Hong, Jea Uk Lee
Carbon Letters Vol.31 No.6 pp.1327-1337 한국탄소학회
In order to extend the business viability of carbon nanotubes (CNTs), research on CNT dispersion in a solvent as well as in polymer matrix should be established. Herein, three kinds of dispersing agents, sodium deoxycholate (DOC), sodium dodecylbenzene sulfonate (NaDDBS), polyvinyl pyrrolidone (PVP), are selected and applied to quantify the dispersibility and dispersion stability of CNT aqueous dispersion. The dispersibility of CNT dispersion with the PVP, evaluated via viscosity and particle size analyses, are superior to those with the DOC and NaDDBS dispersing agents. CNT aqueous solution dispersed with PVP showed slightly higher viscosity and narrower particle size distribution than those with DOC and NaDDBS dispersing agents. In addition, the dispersion stability of CNT dispersion with the PVP, measured via lumisizer analyses, are superior to those with the DOC and NaDDBS dispersing agents. HR-TEM analysis verifies that the outstanding dispersibility and dispersion stability of CNTs in aqueous solution are due to the effect of the robust polymer wrapping of the PVP dispersing agent on the CNT surface. From the results of this study, the guidelines for the selection of the suitable dispersing agents and the systematic evaluation of dispersibility and dispersion stability of CNT dispersions can be suggested.
4,200원
20.
2021.12 구독 인증기관 무료, 개인회원 유료
Fabrication of nitrogen‑doped porous carbon nanofibers for heavy metal ions removal
Joonwon Bae, Jin‑Yong Hong
Carbon Letters Vol.31 No.6 pp.1339-1347 한국탄소학회
In this article, nitrogen (N) doped porous carbon nanofibers (N-PCNF) were prepared by carbonization of polymer-silica nanocomposite precursor, and its application for heavy metal ion removal was demonstrated. Carbon–silica composite nanofibers were obtained by carbonization of electrospun polyacrylonitrile (PAN)-silica nanofiber composites. Subsequent selective etching of silica porogen produced porous carbon nanofibers (PCNF). It was revealed by surface characterization with X-ray photoelectron spectroscopy (XPS) that the surface of the PCNF was nitrogen-doped because N atom from cyanide group in PAN chains remained in the hexagonal carbon structure. The use of the obtained N-PCNF for heavy metal ion ( Hg2+) removal was demonstrated using a simple adsorption test apparatus and 5, 10, 15, 20-tetraphenylporphine tetrasulfonic acid (TPPS) as an indicator. The N-PCNF showed a removal efficiency of 96 and 99% in 10 and 120 min, respectively, indicating a maximum heavy metal ion adsorption capacity at pH 7.0. In addition, heavy metal ion adsorption behavior was also analyzed using common adsorption isotherms. This article provides important information for future research activities regarding control over hazardous substances.
4,000원
내보내기
언어 선택
구매하기

0개의 논문이 장바구니에 담겼습니다.

바로 확인하시겠습니까?

    1 2