Applied Sciences

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11 pages, 3507 KiB

Open AccessArticle

Regeneration Performance of Activated Carbon for Desulfurization

by Zhiguo Sun, Menglu Wang, Jiaming Fan, Yue Zhou and Li Zhang

Appl. Sci. 2020, 10(17), 6107; https://doi.org/10.3390/app10176107 - 3 Sep 2020

Cited by 10 | Viewed by 3081

This study explored the regenerated performance of activated carbon (AC) as SO₂ adsorbent. The optimal conditions of SO₂ removal were determined by experiment, and then the adsorption efficiency of AC was studied by a method of thermal regeneration. The characteristics of [...] Read more.

This study explored the regenerated performance of activated carbon (AC) as SO₂ adsorbent. The optimal conditions of SO₂ removal were determined by experiment, and then the adsorption efficiency of AC was studied by a method of thermal regeneration. The characteristics of regenerated AC were analyzed by Brunauer-Emmett-Teller (BET) and Scanning Electron Microscopy (SEM) methods. The test results showed that the most suitable adsorption conditions were using 4 g of activated carbon, 1.65 L/min gas flue rate, and 5% O₂. During the ten regenerations, the desulfurization efficiency and sulfur capacity of AC still maintained a high level. The characterization results showed that the increase of material surface area and pore volume were 101 m² g⁻¹, and 0.13 cm³ g⁻¹, respectively, after the cycles. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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10 pages, 5328 KiB

Open AccessArticle

Carbon Nanoparticle-Based Electro-Thermal Building Block

by Mohammad Taghi Ahmadi, Neda Mousavi, Truong Khang Nguyen, Seyed Saeid Rahimian Koloor and Michal Petrů

Appl. Sci. 2020, 10(15), 5117; https://doi.org/10.3390/app10155117 - 25 Jul 2020

Viewed by 2557

Abstract

All around the world, researchers have raised concerns about the superlative geometrical, electronic, thermal, chemical and mechanical properties of carbon nanoparticles (CNPs). CNPs with low cost, high performance and prominent intrinsic properties have attracted extensive interest for numerous applications in various fields. Although [...] Read more.

All around the world, researchers have raised concerns about the superlative geometrical, electronic, thermal, chemical and mechanical properties of carbon nanoparticles (CNPs). CNPs with low cost, high performance and prominent intrinsic properties have attracted extensive interest for numerous applications in various fields. Although CNPs have been studied mainly as transistors and sensors, they could also be considered as heat producers. However, this option has scarcely been studied. In this research, a CNP-based electro-thermal building block is synthesized by the arc discharge method in a carbonic medium (high-density polyethylene), and its behavior is investigated. It is shaped in the form of a metal–semiconductor–metal structure (MSM) between metallic electrodes, and in addition, the formation of two back-to-back Schottky diodes is analyzed and their use as CNP-based electro-thermal building blocks are reported. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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9 pages, 2910 KiB

Open AccessArticle

Influence of Current Density on the Microstructure of Carbon-Based Cathode Materials during Aluminum Electrolysis

by Wei Wang and Kai Sun

Appl. Sci. 2020, 10(7), 2228; https://doi.org/10.3390/app10072228 - 25 Mar 2020

Cited by 5 | Viewed by 2072

Abstract

Sodium expansion plays an important role in cathode deterioration during aluminum electrolysis. In this work, the sodium expansion of semigraphitic cathode material has been measured at various cathodic current densities using a modified Rapoport apparatus. We have studied the microstructural changes of carbon [...] Read more.

Sodium expansion plays an important role in cathode deterioration during aluminum electrolysis. In this work, the sodium expansion of semigraphitic cathode material has been measured at various cathodic current densities using a modified Rapoport apparatus. We have studied the microstructural changes of carbon cathodes after aluminum electrolysis using high-resolution transmission electron microscopy (HRTEM). Because of an increasing trend toward higher amperage in retrofitted aluminum reduction cells, an investigation is conducted both at a representative cathode current density (0.45 A/cm²) and at a high cathodic current density (0.7 A/cm²). The results indicate that the microstructures of carbon cathodes can be modified by Joule heating and electrostatic charging with higher current densities during aluminum electrolysis. With the penetration of the sodium and melt, zigzag and armchair edges, disordered carbon, and exfoliation of the surface layers may appear in the interior of the carbon cathode. The penetration of the sodium and melt causes remarkable stresses and strains in the carbon cathodes, that gradually result in performance degradation. This shows that increasing the amperage in aluminum reduction cells may exacerbate the material deterioration of the cathodes. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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7 pages, 3364 KiB

Open AccessArticle

Study of a Carbon Nanowall Synthesized on an MWCNT-Based Buffer Layer for Improvement of Electrical Properties

by Joouk Kim, Chulmin Park, Hosung Jung, Hyungchul Kim, Seokhun Kwon, Hyeokjoo Choi and Hyunil Kang

Appl. Sci. 2020, 10(1), 192; https://doi.org/10.3390/app10010192 - 25 Dec 2019

Cited by 3 | Viewed by 1930

Abstract

We conducted experiments to improve the electrical properties of the CNW (carbon nanowall), which has lower electrical properties than other carbon allotropes such as graphene and CNT (carbon nanotube), and report the results through this article. The carbon nanowall has an amorphous buffer [...] Read more.

We conducted experiments to improve the electrical properties of the CNW (carbon nanowall), which has lower electrical properties than other carbon allotropes such as graphene and CNT (carbon nanotube), and report the results through this article. The carbon nanowall has an amorphous buffer layer, leading to low electrical properties, and MWCNT (multi-walled carbon nanotube) was used as a buffer layer to improve this issue, and then a CNW was grown on it by CVD (chemical vapor deposition). Then, the content of MWCNT was adjusted to 30 µL, 50 µL, and 70 µL to analyze the electrical properties accordingly. Alteration in carrier concentration, carrier mobility and resistivity were observed as electrical properties. Dramatic changes in electrical properties with MWCNT content were identified. The ohmic contact state between the MWCNT-based buffer layer and the CNW was investigated by analysis of the I-V and I-R characteristics and the electrical stability according to the linearity of the curve. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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10 pages, 3655 KiB

Open AccessArticle

Wettability of CNW/ITO Micro Structure for Modification of Surface Hydrophilicity

by Seokhun Kwon, Hyeokjoo Choi, Wonseok Choi and Hyunil Kang

Appl. Sci. 2020, 10(1), 142; https://doi.org/10.3390/app10010142 - 23 Dec 2019

Cited by 5 | Viewed by 2656

Abstract

Although the carbon nanowall is a remarkable material in various fields, it generally shows near hydrophobicity. For modification of hydrophilicity, various modification techniques have been utilized, however, most of the techniques adopted a modification to carbon oxide by chemical processing and plasma treatment, [...] Read more.

Although the carbon nanowall is a remarkable material in various fields, it generally shows near hydrophobicity. For modification of hydrophilicity, various modification techniques have been utilized, however, most of the techniques adopted a modification to carbon oxide by chemical processing and plasma treatment, which induce carbon lattice defects, causing the decline of the carbon nanowall quality. While we introduce an eco-friendly modification technique that causes non-defect of carbon lattice and maintains intrinsic carbon nanowall properties by depositing ITO on pristine-carbon nanowall for inducing hydrophilicity. The morphology of carbon nanowall (CNW)/ indium tin oxide (ITO) microstructure was examined by FE-SEM, and the functional group and oxygen components of ITO were investigated by analyzing XPS. The contact angles were measured for wettability analysis according to the surface thickness of ITO. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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13 pages, 7884 KiB

Open AccessArticle

Facile Preparation of Multilayered Graphene with CO₂ as a Carbon Source

by Hongyu Dong, Shaoqing Guo and Liangfu Zhao

Appl. Sci. 2019, 9(21), 4482; https://doi.org/10.3390/app9214482 - 23 Oct 2019

Cited by 7 | Viewed by 2660

Abstract

A facile and controllable route for fabricating multilayered graphene was provided using CO₂ as a carbon source. A typical multilayered graphene structure was obtained with the reaction between CO₂ and magnesium metal. The reaction was carried out under different CO₂ [...] Read more.

A facile and controllable route for fabricating multilayered graphene was provided using CO₂ as a carbon source. A typical multilayered graphene structure was obtained with the reaction between CO₂ and magnesium metal. The reaction was carried out under different CO₂ gas flows, reaction temperatures, and reaction times with two types of metal Mg (Mg powder and Mg ribbon). Moreover, the effect of different concentrations of HCl solution for sample post-processing was discussed in this study. The results of transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), Raman spectroscopy and X-ray powder diffraction (XRD) confirm the formation of multilayered graphene. This work proposed a new method for a controllable way to produce multilayered graphene with gaseous CO₂ as a carbon source. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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11 pages, 2918 KiB

Open AccessArticle

Bioelectricity Generation by Corynebacterium glutamicum with Redox-Hydrogel-Modified Carbon Electrode

by Soo Youn Lee, Jiho Min, Sangmin Lee, Hana Nur Fitriana, Min-Sik Kim, Gwon Woo Park and Jin-Suk Lee

Appl. Sci. 2019, 9(20), 4251; https://doi.org/10.3390/app9204251 - 11 Oct 2019

Cited by 4 | Viewed by 2750

Abstract

This work studied Gram-positive and weak electricigen Corynebacterium glutamicum for its ability to transfer electrons and to produce bioelectricity in microbial fuel cells (MFCs). The electrochemical and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) results revealed that C. glutamicum had the potential to mediate electron [...] Read more.

This work studied Gram-positive and weak electricigen Corynebacterium glutamicum for its ability to transfer electrons and to produce bioelectricity in microbial fuel cells (MFCs). The electrochemical and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) results revealed that C. glutamicum had the potential to mediate electron transfer to an electrode by emitting its own extracellular electron shuttles such as flavins. To enhance the current collection from C. glutamicum, a carbon cloth anode was modified with ferrocene-branched chitosan hydrogel (redox-hydrogel). The maximum current density of the ferrocene-branched chitosan redox hydrogel anode with C. glutamicum was drastically increased to 120 µA cm⁻² relative to a bare carbon cloth electrode with C. glutamicum (261 nA cm⁻²). The power density and polarization curves for the MFC operation with the redox-hydrogel-modified anode showed that C. glutamicum effectively generated bioelectricity by means of the redox-hydrogel anode. The results suggest that, in such an electro-fermentation process, ferrocene-branched chitosan hydrogel grafted onto an anode surface would also facilitate both electron transfer from C. glutamicum to the anode and bioelectricity generation. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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8 pages, 3387 KiB

Open AccessArticle

Experiment Research on Micro-/Nano Processing Technology of Graphite as Basic MEMS Material

by Cheng Zhang, Yijin Liu, Mingge Wu and Ningbo Liao

Appl. Sci. 2019, 9(15), 3103; https://doi.org/10.3390/app9153103 - 31 Jul 2019

Cited by 2 | Viewed by 2830

Abstract

Graphite is expected to be a common choice for basic microelectromechanical-system (MEMS) material in the future. However, in order to become a basic MEMS material, it is very important for graphite to be adapted to the commonly-used micro-/nanoprocessing technology. Therefore, this paper used [...] Read more.

Graphite is expected to be a common choice for basic microelectromechanical-system (MEMS) material in the future. However, in order to become a basic MEMS material, it is very important for graphite to be adapted to the commonly-used micro-/nanoprocessing technology. Therefore, this paper used a directly lithography and etching process to study micro-, /nanoprocessing on graphite. The results show that the graphite surface is suitable for lithography, and that different shapes and sizes of photoresist patterns can be directly fabricated on the graphite surface. In addition, the micro-meter height of photoresist could still resist plasma etching when process nanometers height of graphite structures. Therefore, graphite with photoresist patterns were directly processed by etching, and nanometer amounts of graphite were etched. Moreover, micro-/nanoscale graphite structure with height ranges from 29.4 nm–30.9 nm were fabricated with about 23° sidewall. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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10 pages, 4118 KiB

Open AccessArticle

Preparation of Amphiphilic Chitosan–Graphene Oxide–Cellulose Nanocrystalline Composite Hydrogels and Their Biocompatibility and Antibacterial Properties

by Ming-Chien Yang, Yi-Qun Tseng, Kun-Ho Liu, Yu-Wei Cheng, Wan-Tzu Chen, Wei-Ting Chen, Chia-Wei Hsiao, Ming-Chi Yung, Chuan-Chih Hsu and Ting-Yu Liu

Appl. Sci. 2019, 9(15), 3051; https://doi.org/10.3390/app9153051 - 29 Jul 2019

Cited by 20 | Viewed by 3562

Abstract

Environmental-friendly nanocomposite hydrogels of carboxymethyl-hexanoyl chitosan (CHC), graphene oxide (GO) and cellulose nanocrystals (CNCs) were combined to produce a bio-hydrogel with great biocompatibility and antibacterial ability. The size of the GO nanosheets was about 200–500 nm, and the CNCs had a length of [...] Read more.

Environmental-friendly nanocomposite hydrogels of carboxymethyl-hexanoyl chitosan (CHC), graphene oxide (GO) and cellulose nanocrystals (CNCs) were combined to produce a bio-hydrogel with great biocompatibility and antibacterial ability. The size of the GO nanosheets was about 200–500 nm, and the CNCs had a length of 100–200 nm and a width of 10–20 nm, as shown by transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) was utilized for the analysis of the oxygen functional groups of GO. The homogeneous dispersion of the CHC/GO/CNC nanocomposite hydrogel showed significantly higher water absorption capacity and water retention capability. In addition, inhibition of a variety of microorganisms (gram-negative and gram-positive bacteria and fungi) by the introduction of the CHC/GO/CNC nanocomposite hydrogel demonstrated that there is a great opportunity to use it in the bio-medical field, such as for plastic masks and wound dressings. Full article

(This article belongs to the Special Issue Carbon Nanostructures: Fabrication and Applications)

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