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28 pages, 4534 KB

Open AccessArticle

Mechanistic Evaluation of Pb(II) Adsorption on Magnetic Activated Carbon/Fe₃O₄ Composites: Influence of Hydrothermal and Ultrasonic Synthesis Routes

by Gaukhar Smagulova, Aigerim Imash, Akniyet Baltabay, Aruzhan Keneshbekova, Alisher Abdisattar, Ramazan Kazhdanbekov, Aidos Lesbayev and Zulkhair Mansurov

C 2025, 11(4), 83; https://doi.org/10.3390/c11040083 - 4 Nov 2025

Abstract

This study presents a comparative analysis of two synthesis approaches for fabricating magnetic sorbents based on activated carbon (AC) incorporated with magnetite (Fe₃O₄) nanoparticles: hydrothermal synthesis and ultrasonic treatment. The results demonstrate that ultrasonic-assisted synthesis yields a magnetically responsive [...] Read more.

This study presents a comparative analysis of two synthesis approaches for fabricating magnetic sorbents based on activated carbon (AC) incorporated with magnetite (Fe₃O₄) nanoparticles: hydrothermal synthesis and ultrasonic treatment. The results demonstrate that ultrasonic-assisted synthesis yields a magnetically responsive composite, us-AC/Fe₃O₄, exhibiting a Pb²⁺ removal efficiency of 92.84%, which is comparable to that of pristine activated carbon (99.0%). A key advantage of the synthesized composite lies in its facile recovery via magnetic separation following adsorption, rendering it a promising candidate for the remediation of heavy metal-contaminated water. Kinetic modeling suggests a dual adsorption mechanism: initial stages are governed by physisorption, while chemisorption dominates in the later phases. Adsorption isotherm modeling demonstrated that the Langmuir model provided the best description of Pb²⁺ adsorption on AC and us-AC/Fe₃O₄, with the highest sorption capacities observed for pristine activated carbon, followed by the ultrasonically modified composite, and comparatively lower values for the hydrothermally treated material. These findings underscore the potential of ultrasonic processing as an effective route for developing magnetically separable sorbents with high performance in aqueous heavy metal removal. Full article

(This article belongs to the Special Issue Carbons for Health and Environmental Protection (2nd Edition))

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12 pages, 2259 KB

Open AccessArticle

Bituminous Coal-Derived Carbon Anode: Molten Salt-Assisted Synthesis and Enhanced Performance in Sodium-Ion Battery

by Yuxuan Du, Jian Wang, Peihua Li, Yalong Wang, Yibo Zhao and Shuwei Chen

C 2025, 11(4), 82; https://doi.org/10.3390/c11040082 - 27 Oct 2025

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Abstract

The high-efficiency and clean utilization of coal resources is a key strategy for new energy development, and converting coal into carbon materials offers a promising route to valorize bituminous coal. However, fabricating high-performance bituminous coal-derived carbon for sodium ion (Na⁺) insertion/extraction [...] Read more.

The high-efficiency and clean utilization of coal resources is a key strategy for new energy development, and converting coal into carbon materials offers a promising route to valorize bituminous coal. However, fabricating high-performance bituminous coal-derived carbon for sodium ion (Na⁺) insertion/extraction remains a major challenge, as it is difficult to regulate the carbon’s microstructural properties to match Na⁺ storage demands. Herein, we propose a molten salt-assisted carbonization strategy to prepare bituminous coal-derived hard carbon (HC) for use as a sodium-ion battery (SIB) anode material, and we focus on regulating the structure of carbon. The results show that as-prepared HC exhibits significantly enhanced electrochemical performance for Na⁺ storage when the molar ratio of NaCl to KCl is 1:1. The optimized material achieves a reversible capacity of 366.7 mAh g⁻¹ at the current density of 100 mA g⁻¹ after 60 cycles and retains 99% of its initial capacity after 500 cycles at a current density of 1 A g⁻¹. The main finding is that the lattice spacing can be regulated by tuning the composition of the molten salt, and anode performance is enhanced remarkably by changes in the HC structure. This work provides a feasible strategy for designing and preparing a bituminous coal-derived carbon anode material for use in the energy storage field. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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13 pages, 1919 KB

Open AccessCommunication

An Innovative Solution Method for the Evaluation of CO₂ Disposal in the Seafloor Environment

by Boyun Guo, Muhammad Towhidul Islam and Vincent Nana Boah Amponsah

C 2025, 11(4), 81; https://doi.org/10.3390/c11040081 - 27 Oct 2025

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Abstract

Injecting carbon dioxide (CO₂) into underground geo-structures, such as depleted oil and gas reservoirs, reduces man-made CO₂ emissions into the atmosphere or removes what is already there. Studies have identified the risks of CO₂ leaks from these underground geo-structures [...] Read more.

Injecting carbon dioxide (CO₂) into underground geo-structures, such as depleted oil and gas reservoirs, reduces man-made CO₂ emissions into the atmosphere or removes what is already there. Studies have identified the risks of CO₂ leaks from these underground geo-structures through wellbores back into the atmosphere due to the high mobility of CO₂ in gaseous and supercritical states. This work aims at proposing a novel method of CO₂ storage using the Joule–Thomson cooling effect to effectively produce CO₂ hydrates on seafloors, with an objective to avoid the leakage risks of storage in depleted oil and gas reservoirs. Through the combination of thermodynamic data, analysis of hydrate stability, and engineering design with established working parameters, this study proposes an innovative concept and an enabling process for CO₂ placement onto seafloors for safe storage. The results of case analysis of typical seawater conditions reveal that the appropriate seafloor depth ranges for different applications (>1900 m for liquid CO₂ and 700–1900 m for CO₂ hydrate). An engineering design procedure for real applications is outlined. Full article

(This article belongs to the Section Carbon Cycle, Capture and Storage)

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12 pages, 1658 KB

Open AccessArticle

Supercapacitor Using Polypyrrole and Carbon Nanotube Composite as Electrodes

by Arturo Tepale-Cortés, Hilda Moreno-Saavedra, Marquidia J. Pacheco, Joel O. Pacheco, Celso Hernández-Tenorio and Ricardo Valdivia

C 2025, 11(4), 80; https://doi.org/10.3390/c11040080 - 24 Oct 2025

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Abstract

Electrodes and electrolytes are critical components for the performance of supercapacitors. In this study, supercapacitors with different interfaces were assembled using polypyrrole (PPy) or a polypyrrole–carbon nanotube (PPy-CNT) composite as active materials, and dimethyl sulfoxide (DMSO) and sodium chloride (NaCl) were used as [...] Read more.

Electrodes and electrolytes are critical components for the performance of supercapacitors. In this study, supercapacitors with different interfaces were assembled using polypyrrole (PPy) or a polypyrrole–carbon nanotube (PPy-CNT) composite as active materials, and dimethyl sulfoxide (DMSO) and sodium chloride (NaCl) were used as electrolytes. Electrochemical measurements were obtained by cyclic voltammetry (CV) at a scan rate of 20 mV/s and galvanostatic charge–discharge (GCD) measurements at a scan rate of 50 µA/s. The results suggest that the supercapacitor with a PPy-CNT composite and NaCl electrolyte has promising electrochemical characteristics. Full article

(This article belongs to the Special Issue Carbon and Related Composites for Sensors and Energy Storage: Synthesis, Properties, and Application (2nd Edition))

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21 pages, 677 KB

Open AccessReview

Carbon Black Nanoparticles in Non-Instrumental Immunoassays Development for Diagnostic Applications

by Maria Nikitina, Stepan Devyatov and Mikhail Rayev

C 2025, 11(4), 79; https://doi.org/10.3390/c11040079 - 14 Oct 2025

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Abstract

Due to their unique physicochemical properties, carbon black nanoparticles represent a promising alternative for solving analytical problems. However, diagnostic reagents based on carbon black nanoparticles have not yet found widespread practical application. This review examines the development and application of carbon black nanoparticle [...] Read more.

Due to their unique physicochemical properties, carbon black nanoparticles represent a promising alternative for solving analytical problems. However, diagnostic reagents based on carbon black nanoparticles have not yet found widespread practical application. This review examines the development and application of carbon black nanoparticle conjugates with recognition molecules as diagnostic reagents in test systems that enable non-instrumental interpretation of results. The review critically evaluates the methods for synthesis and characterization of carbon black-based diagnostic reagents. Furthermore, the review summarizes and discusses existing studies comparing the effectiveness of carbon black nanoparticle-based bioconjugates with traditional colorimetric labels. The scientific articles included in the review were carefully analyzed for the presence of an assessment of the reproducibility of methods for obtaining diagnostic reagents based on carbon black nanoparticles and their long-term storage. The main challenges and future prospects of using carbon black nanoparticles in immunoassays are discussed. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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14 pages, 8360 KB

Open AccessReview

Structural Models of Non-Graphitising Carbon: A Brief History

by Peter J. F. Harris

C 2025, 11(4), 78; https://doi.org/10.3390/c11040078 - 14 Oct 2025

Viewed by 418

Abstract

Non-graphitising carbons are an important class of solid carbon materials which cannot be transformed into graphite by heat treatment, even at 3000 °C. Also known as hard carbons, they are of growing importance as anode materials for lithium-ion or sodium-ion batteries. When activated [...] Read more.

Non-graphitising carbons are an important class of solid carbon materials which cannot be transformed into graphite by heat treatment, even at 3000 °C. Also known as hard carbons, they are of growing importance as anode materials for lithium-ion or sodium-ion batteries. When activated they are widely used in the purification of air and water supplies. However, despite decades of research, the detailed atomic structures of these materials has still not been fully established. Many structural models have been put forward, beginning with the classic work of Rosalind Franklin, but none have gained universal acceptance. This review gives a historical survey of models for the structure of non-graphitising carbons and summarizes the latest thinking on the subject, which is based on the idea that the structure contains non-hexagonal rings, as in the fullerenes and fullerene-related structures. Studies using aberration-corrected transmission electron microscopy have provided important support for this idea. Full article

(This article belongs to the Special Issue 10th Anniversary of C — Journal of Carbon Research)

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15 pages, 3266 KB

Open AccessArticle

Nano-Functionalized Magnetic Carbon Composite for Purification of Man-Made Polluted Waters

by Tetyana I. Melnychenko, Vadim M. Kadoshnikov, Oksana M. Arkhipenko, Tetiana I. Nosenko, Iryna V. Mashkina, Lyudmila A. Odukalets, Sergey V. Mikhalovsky and Yuriy L. Zabulonov

C 2025, 11(4), 77; https://doi.org/10.3390/c11040077 - 13 Oct 2025

Viewed by 524

Abstract

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. [...] Read more.

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. The aim of this work is to develop a nano-functionalized composite, comprising magnetically responsive, thermally expanded graphite (TEG) and the natural clay bentonite, and to assess its ability to purify man-made contaminated waters. Throughout the course of the research, the methods of scanning electron microscopy, optical microscopy, dynamic light scattering, radiometry, and atomic absorption spectrophotometry were used. The use of the TEG–bentonite composite for the purification of the model water, simulating radioactively contaminated nuclear power plant (NPP) effluent, reduced the content of organic substances by 10–15 times, and the degree of extraction of cesium, strontium, cobalt, and manganese was between 81.4% and 98.8%. The use of the TEG–bentonite composite for the purification of real radioactively contaminated water obtained from the object “Shelter” (“Ukryttya” in Ukrainian), in the Chernobyl Exclusion Zone, Ukraine, with high activity, containing organic substances, including micro- and nanoplastics, reduced the radioactivity by three orders of magnitude. The use of cesium-selective sorbents for additional purification of the filtrate allowed for further decontamination of radioactively contaminated water with an efficiency of 99.99%. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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33 pages, 5484 KB

Open AccessArticle

Comparative Study of Graphite Exfoliation Techniques Using Nafion as a Surfactant

by Anna O. Krasnova, Nadezhda V. Glebova, Andrey A. Nechitailov, Angelina G. Kastsova, Anna O. Pelageikina, Demid A. Kirilenko, Alexander V. Shvidchenko, Mikhail S. Shestakov, Aleksandra V. Koroleva and Ekaterina K. Khrapova

C 2025, 11(4), 76; https://doi.org/10.3390/c11040076 - 9 Oct 2025

Viewed by 488

Abstract

This work presents a comparative study of graphene exfoliation technologies from various graphite precursors—spectral graphite and thermally expanded graphite (Graflex)—using ultrasonic treatment and electrochemical methods in the presence of the ionic surfactant Nafion. The influence of exfoliation parameters, the nature of the starting [...] Read more.

This work presents a comparative study of graphene exfoliation technologies from various graphite precursors—spectral graphite and thermally expanded graphite (Graflex)—using ultrasonic treatment and electrochemical methods in the presence of the ionic surfactant Nafion. The influence of exfoliation parameters, the nature of the starting material, and the presence of surfactant additives on the morphology, dispersibility, stability, and structural characteristics of the resulting graphene-containing dispersions was investigated. Particular attention is paid to a two-step technology combining pulsed electrochemical exfoliation with subsequent mild ultrasonic treatment. Comprehensive characterization of the samples was carried out using UV–Vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), electron microscopy, electron diffraction (ED), dynamic light scattering (DLS), and X-ray photoelectron spectroscopy (XPS). It was found that the use of Nafion significantly enhances exfoliation efficiency and contributes to the stabilization of the dispersions. Graphene sheets obtained from Graflex exhibit significantly larger lateral dimensions (up to 1 μm or more) compared to those exfoliated from spectral graphite (100–300 nm). The approach combining the use of Graflex and pulsed electrochemical exfoliation in the presence of Nafion with subsequent low-power ultrasonic treatment enables the production of few-layer graphene (1–3 layers) with high stability. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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18 pages, 3642 KB

Open AccessArticle

Enhanced Removal of Photosensitive Antibiotics in Water Using CO₂: A Beneficial Exploration of CO₂ Resource Utilization

by Miaomiao Ye, Jingqiu Wu, Qiuyuan Weng, Tengchao Bi and Xiaowei Liu

C 2025, 11(4), 75; https://doi.org/10.3390/c11040075 - 9 Oct 2025

Viewed by 503

Abstract

The utilization of carbon dioxide (CO₂) offers an effective approach for alleviating the carbon-reduction pressures associated with fossil energy consumption. However, studies on the use of CO₂ as an auxiliary agent in water treatment to enhance the removal of emerging [...] Read more.

The utilization of carbon dioxide (CO₂) offers an effective approach for alleviating the carbon-reduction pressures associated with fossil energy consumption. However, studies on the use of CO₂ as an auxiliary agent in water treatment to enhance the removal of emerging contaminants are limited. In this study, the photodegradation of ciprofloxacin (CIP) was investigated using ultraviolet (UV) irradiation combined with CO₂ dosing (UV/CO₂). The results demonstrated that the UV/CO₂ system effectively degraded CIP, with CO₂ concentration and solution pH exerting a critical influence. Inorganic anions and metal cations had negligible effects on CIP degradation efficiency, whereas natural organic matter (NOM) had a pronounced inhibitory effect. Mechanistic analysis revealed that superoxide radicals (

\cdot O_{2}^{-}

) and carbonate radicals (

{CO}_{3}^{• -}

) were the primary oxidizing species, whereas the excited triplet state of CIP (³CIP*) and singlet oxygen played crucial roles in initiating radical generation. LC–MS analysis and density functional theory calculations indicated that the main degradation routes involved defluorination, decarboxylation, and epoxidation of the piperazine ring. Toxicity assessment indicated that the transformation products generated by UV/CO₂ were less toxic than the parent compound. Furthermore, the UV/CO₂ process demonstrated high energy efficiency, with a low electrical energy per order (EEO) value of 0.4193 kWh·m⁻³·order⁻¹. These findings suggest that the UV/CO₂ system is a promising alternative for the treatment of photosensitive organic pollutants and provides a beneficial pathway for CO₂ utilization. Full article

(This article belongs to the Section CO₂ Utilization and Conversion)

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15 pages, 5399 KB

Open AccessArticle

Spatially Controlled Plasma Jet Synthesis of Carbyne Encapsulated in Carbon Nanotubes

by Oleg A. Streletskiy, Ilya A. Zavidovskiy, Vladimir A. Baidak, Anatoly S. Pashchina, Abdusame A. Khaidarov and Vladimir L. Bychkov

C 2025, 11(4), 74; https://doi.org/10.3390/c11040074 - 9 Oct 2025

Viewed by 553

Abstract

Carbyne, a linear chain of carbon atoms, possesses extraordinary properties but has remained elusive due to its extreme instability. While encapsulation within carbon nanotubes stabilizes carbyne, a lack of synthetic control over its location has prevented practical use. Here, we introduce a spatially [...] Read more.

Carbyne, a linear chain of carbon atoms, possesses extraordinary properties but has remained elusive due to its extreme instability. While encapsulation within carbon nanotubes stabilizes carbyne, a lack of synthetic control over its location has prevented practical use. Here, we introduce a spatially localized plasma jet technique that enables the guided spatially selective self-assembly of carbyne encapsulated within multiwalled carbon nanotube (carbyne@MWCNT) hybrids on graphite surfaces. This method uses intense, localized plasma energy to simultaneously grow nanotubes and synthesize carbyne within them, where the nanotube structure and carbyne encapsulation are governed by the localized heat flux distribution. Beyond confirming carbyne formation via its characteristic Raman mode, we discover its second-order vibrational spectrum, confirming anharmonic interactions between the chain and its nanotube container. This spatial control can be used to architect functional carbyne@MWCNT arrays, whose potential applications are discussed in detail. Full article

(This article belongs to the Special Issue Micro/Nanofabrication of Carbon-Based Devices and Their Applications)

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11 pages, 1486 KB

Open AccessArticle

Study of the Iodine Fixation over High Surface Area Graphite (HSAG-100) Under Mild Conditions

by Angel Maroto-Valiente, Carla A. Blanco-Camus, Ana I. Mártir Bueno, Elena M. Mesa-Bribián and Jesús Alvarez-Rodríguez

C 2025, 11(4), 73; https://doi.org/10.3390/c11040073 - 30 Sep 2025

Viewed by 673

Abstract

The controlled incorporation of halogens into carbon materials remains a challenge, particularly under mild and scalable conditions. In this work, we investigate the fixation of iodine on high-surface-area graphite (HSAG-100) using green solvents and moderate temperatures. Commercial HSAG was treated with iodine in [...] Read more.

The controlled incorporation of halogens into carbon materials remains a challenge, particularly under mild and scalable conditions. In this work, we investigate the fixation of iodine on high-surface-area graphite (HSAG-100) using green solvents and moderate temperatures. Commercial HSAG was treated with iodine in aqueous and in organic media, with and without promoters, and characterized by XPS, LEIS, N₂ physisorption, TGA/TPD, and XRD. The results reveal that iodine contents up to ~0.6 at% can be achieved, with incorporation strongly influenced by solvent and reaction time. XPS and LEIS confirmed the presence of C–I bonds, while BET analysis showed only moderate decreases in surface area and unchanged mesopore size distribution. Thermogravimetric and TPD analyses demonstrated the high thermal stability of C–I species, and XRD patterns ruled out intercalation between graphene layers. Collectively, these findings demonstrate that iodine can be covalently anchored to HSAG under mild conditions, preserving the graphitic structure and generating stable edge functionalities, thus opening a route for the design of halogen-doped carbons for catalytic and electrochemical applications. Full article

(This article belongs to the Section Carbon Materials and Carbon Allotropes)

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