C | An Open Access Journal from MDPI

14 pages, 18495 KiB

Open AccessArticle

Analysis of Biochar–Cement Composites by SEM/EDS: Interfacial Interactions and Effects on Mechanical Strength

by Rafaela Paula, Jaqueline Carvalho, Antônio Júnior, Filipe Fagundes, Robson de Lima, Evaneide Lima, Carlos Oliveira, Magno de Oliveira, Augusto Bezerra, Osania Ferreira and Alan Machado

C 2025, 11(3), 45; https://doi.org/10.3390/c11030045 - 29 Jun 2025

Abstract

Portland cement production is one of the main global sources of CO₂ emissions, driving the search for sustainable solutions to reduce its environmental footprint. This study evaluated the use of biochar derived from sugarcane bagasse as a partial cement replacement in cementitious [...] Read more.

Portland cement production is one of the main global sources of CO₂ emissions, driving the search for sustainable solutions to reduce its environmental footprint. This study evaluated the use of biochar derived from sugarcane bagasse as a partial cement replacement in cementitious composites, aiming to investigate its effects on mechanical and microstructural properties. Composites were prepared with 0, 2, and 5 (% w w⁻¹) biochar at two water-to-cement (w/c) ratios: 0.28 and 0.35. It was hypothesized that the porous structure and carbon-rich composition of biochar could enhance the microstructure of the cementitious matrix and contribute to strength development. Characterization of the biochar indicated compliance with the European Biochar Certificate (EBC) standard, high thermal stability, and notable water retention capacity. Mechanical testing revealed that incorporating 5% w w⁻¹ biochar increased compressive strength by up to 48% in the 0.35 w/c formulation compared to the control. Microstructural analyses (SEM/EDS) showed good interaction between the biochar and the cementitious matrix, with the formation of hydration products at the interfaces. The results confirm the potential of sugarcane bagasse biochar as a supplementary cementitious material, promoting more sustainable composites with improved mechanical performance and reduced environmental impact. Full article

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

► Show Figures

Graphical abstract

19 pages, 1917 KiB

Open AccessArticle

Bimetallic Copper–Indium Co-Doped Titanium Dioxide Towards Electrosynthesis of Urea from Carbon Dioxide and Nitrate

by Youcai Meng, Tianran Wei, Zhiwei Wang, Caiyun Wang, Junyang Ding, Yang Luo and Xijun Liu

C 2025, 11(3), 44; https://doi.org/10.3390/c11030044 - 27 Jun 2025

Abstract

Electrocatalytic urea synthesis offers great potential for sustainable strategies through CO₂ and NO₃⁻ reduction reactions. However, the development of high-performance catalysts is often hampered by the complexity of synthetic methodologies and the unresolved nature of C-N coupling pathways. In this [...] Read more.

Electrocatalytic urea synthesis offers great potential for sustainable strategies through CO₂ and NO₃⁻ reduction reactions. However, the development of high-performance catalysts is often hampered by the complexity of synthetic methodologies and the unresolved nature of C-N coupling pathways. In this study, we present a copper–indium co-doped titanium dioxide (CuIn-TiO₂) catalyst that exhibits remarkable efficacy in enhancing the synergistic reduction of CO₂ and NO₃⁻ to produce urea. The bimetallic CuIn site functions as the primary active site for the C-N coupling reaction, achieving a urea yield rate of 411.8 μg h⁻¹ mg_cat⁻¹ with a Faradaic efficiency of 6.7% at −0.8 V versus reversible hydrogen electrode (vs. RHE). A body of experimental and theoretical research has demonstrated that the nanoscale particles enhance the density of active sites and improve the feasibility of reactions on the surface of TiO₂. The co-doping of Cu and In has been shown to significantly enhance electronic conductivity, increase the adsorption affinity for *CO₂ and *NO₃⁻, and promote the C-N coupling process. The CuIn-TiO₂ catalyst has been demonstrated to effectively promote the reduction of NO₃⁻ and CO₂, as well as accelerate the C-N coupling reaction. This effect is a result of a synergistic interaction among the catalyst’s components. Full article

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

► Show Figures

Graphical abstract

10 pages, 1436 KiB

Open AccessArticle

Theoretical Investigation of O₂ and CO₂ Adsorption on Small PdNi Clusters Supported on N-Doped Graphene Quantum Dots

by Brenda García-Hilerio, Lidia Santiago-Silva, Pastor T. Matadamas-Ortiz, Alejandro Gomez-Sanchez, Víctor A. Franco-Luján and Heriberto Cruz-Martínez

C 2025, 11(3), 43; https://doi.org/10.3390/c11030043 - 27 Jun 2025

Abstract

A density functional theory (DFT) investigation was conducted to study the O₂ and CO₂ adsorption on very small Pd_3−nNi_n (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. [...] Read more.

A density functional theory (DFT) investigation was conducted to study the O₂ and CO₂ adsorption on very small Pd_3−nNi_n (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. First, the interaction between Pd_3−nNi_n (n = 0–2) clusters and N-GQDs was analyzed. Subsequently, the adsorption behavior of O₂ and CO₂ molecules on the supported clusters was examined. The calculated interaction energies (E_int) of Pd_3−nNi_n (n = 0–2) clusters on N-GQDs were found to be higher than those on pristine graphene, indicating enhanced cluster stability on N-GQDs. Furthermore, the adsorption energies (E_ads) of the O₂ molecule on the Pd₃ and Pd₂Ni clusters deposited on N-GQDs were similar. Meanwhile, the PdNi₂ cluster deposited on N-GQDs exhibited the highest E_ads (−1.740). The E_ads of CO₂ on Pd_3−nNi_n (n = 0–2) clusters embedded in N-GQDs were observed to be close to or exceed 1 eV. Upon adsorption of O₂ and CO₂ on the Pd_3−nNi_n (n = 0–2) clusters supported on N-GQDs, an elongation of the O–O and C–O bond lengths was observed, respectively. This structural change may facilitate the dissociation of these molecules on the supported clusters. Full article

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

► Show Figures

Graphical abstract

14 pages, 61510 KiB

Open AccessArticle

Enhancing High-Temperature Oxidation Stability of Recycled Carbon Fibers Through Ceramic Coating

by Carmela Borriello, Sabrina Portofino, Loredana Tammaro, Pierpaolo Iovane, Gabriella Rametta and Sergio Galvagno

C 2025, 11(3), 42; https://doi.org/10.3390/c11030042 - 26 Jun 2025

Abstract

Carbon fiber-reinforced composites (CFRCs) have attracted considerable attention in recent years due to their excellent properties, enabling their use across various sectors. However, their application at high temperatures is limited by the fibers’ lack of oxidation resistance. This study demonstrates a significant advancement [...] Read more.

Carbon fiber-reinforced composites (CFRCs) have attracted considerable attention in recent years due to their excellent properties, enabling their use across various sectors. However, their application at high temperatures is limited by the fibers’ lack of oxidation resistance. This study demonstrates a significant advancement in enhancing the oxidation stability performance of carbon fiber-reinforced composites (CFRCs) by developing a silicon carbide (SiC) coating through the ceramization of carbon fibers using silicon (Si) powder. For the first time, this method was applied to recycled carbon fibers from CF thermoplastic composites. The key findings include the successful formation of a uniform SiC coating, with coating thickness increasing with process duration and decreasing at higher temperatures. The treated fibers exhibited substantially improved oxidation resistance, maintaining structural stability above 700 °C—markedly better than that of their uncoated counterparts. Thermogravimetric analysis confirmed that oxidation resistance varied depending on the CF/Si ratio, highlighting this parameter’s critical role. Overall, this study offers a viable pathway to enhance the thermal durability of recycled carbon fibers for high-temperature applications. Full article

(This article belongs to the Special Issue High-Performance Carbon Materials and Their Composites (2nd Edition))

► Show Figures

Graphical abstract

13 pages, 6606 KiB

Open AccessArticle

Preparation and Properties of C/C-(TiZrHfNbTa)C Composites via Inorganic Salt Precursor Method

by Haibo Ouyang, Jiyong Liu, Cuiyan Li, Tianzhan Shen, Jiaqi Liu, Mengyao He, Yanlei Li and Leer Bao

C 2025, 11(3), 41; https://doi.org/10.3390/c11030041 - 25 Jun 2025

Abstract

Using low-cost transition-metal chlorides and furfuryl alcohol as raw materials, the (TiZrHfNbTa)C precursor was prepared, and a three-dimensional braided carbon fiber preform (C/C) coated with pyrolytic carbon (PyC) was used as the reinforcing material. A C/C-(TiZrHfNbTa)C composite was successfully fabricated through the precursor [...] Read more.

Using low-cost transition-metal chlorides and furfuryl alcohol as raw materials, the (TiZrHfNbTa)C precursor was prepared, and a three-dimensional braided carbon fiber preform (C/C) coated with pyrolytic carbon (PyC) was used as the reinforcing material. A C/C-(TiZrHfNbTa)C composite was successfully fabricated through the precursor impregnation pyrolysis (PIP) process. Under extreme oxyacetylene ablation conditions (2311 °C/60 s), this composite material demonstrated outstanding ablation resistance, with a mass ablation rate as low as 0.67 mg/s and a linear ablation rate of only 20 μm/s. This excellent performance can be attributed to the dense (HfZr)₆(TaNb)₂O₁₇ oxide layer formed during ablation. This oxide layer not only has an excellent anti-erosion capability but also effectively acts as an oxygen diffusion barrier, thereby significantly suppressing further ablation and oxidation within the matrix. This study provides an innovative strategy for the development of low-cost ultra-high-temperature ceramic precursors and opens up a feasible path for the efficient preparation of C/C-(TiZrHfNbTa)C composites. Full article

(This article belongs to the Special Issue High-Performance Carbon Materials and Their Composites (2nd Edition))

► Show Figures

Graphical abstract

17 pages, 5479 KiB

Open AccessArticle

Fracture Mechanics of Tetragraphene: Effects of Structural Variations and Loading Conditions

by Elnaz Haddadi and Alireza Tabarraei

C 2025, 11(3), 40; https://doi.org/10.3390/c11030040 - 24 Jun 2025

Abstract

Despite the promising electronic properties of graphene, its lack of an intrinsic bandgap limits its applicability in semiconductor technologies. This has catalyzed the investigation of newly developed two-dimensional carbon materials, including tetragraphene (TG), a quasi-2D semiconducting material featuring a combination of hexagonal and [...] Read more.

Despite the promising electronic properties of graphene, its lack of an intrinsic bandgap limits its applicability in semiconductor technologies. This has catalyzed the investigation of newly developed two-dimensional carbon materials, including tetragraphene (TG), a quasi-2D semiconducting material featuring a combination of hexagonal and tetragonal rings. This study aims to investigate the mechanical and fracture behaviors of TG using density functional theory (DFT) and molecular dynamics (MD) simulations, studying two distinct atomic configurations of tetragraphene. DFT simulations assess the mechanical properties, while MD simulations explore the fracture dynamics subjected to mixed mode I (opening mode) and mode II (in-plane shear mode) loading. Our analysis focuses on the influence of loading phase angle, crack edge chirality, crack tip configuration, and temperature on crack propagation paths and critical stress intensity factors (SIFs) in TG structures. Our results show that the critical SIF varies by 12.5–21% depending on the crack chirality. Across all loading conditions, increasing the temperature ranging from 300 K to 2000 K reduces the critical SIF by 10–45%, with the largest reductions observed under pure mode I loading. These outcomes offer important insights into the structural integrity of TG and inform its potential integration into flexible nanoelectronic devices, where mechanical reliability is essential. Full article

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

► Show Figures

Figure 1

3 pages, 186 KiB

Open AccessEditorial

Editorial for Special Issue “Nanoporous Carbons for Hydrogen Sorption and Electrochemical Energy Storage”

by Nikolaos Kostoglou and Claus Rebholz

C 2025, 11(2), 39; https://doi.org/10.3390/c11020039 - 19 Jun 2025

Abstract

Increasing global energy demand and the need for sustainable energy solutions have sparked significant interest in carbon-based materials for energy conversion and storage [...] Full article

(This article belongs to the Special Issue Nanoporous Carbons for Hydrogen Sorption and Electrochemical Energy Storage)

25 pages, 4925 KiB

Open AccessArticle

Chestnut Waste-Derived Fe-Based Photocatalyst for Diclofenac Degradation

by Marianna Guagliano, Ana Bahamonde, Maurizio Bellotto, Cinzia Cristiani, Elisabetta Finocchio, Antonio Gasco, Virginia Muelas-Ramos, Karla Jiménez-Bautista, Christian de los Ríos and Daphne Hermosilla

C 2025, 11(2), 38; https://doi.org/10.3390/c11020038 - 6 Jun 2025

Abstract

This study aims to demonstrate the feasibility of the use of chestnut waste as a green and circular material for developing iron-based photocatalysts for non-steroidal anti-inflammatory drug (NSAID) photodegradation. Four Fe-based catalysts and two pristine biochars were obtained upon a pyrolysis process at [...] Read more.

This study aims to demonstrate the feasibility of the use of chestnut waste as a green and circular material for developing iron-based photocatalysts for non-steroidal anti-inflammatory drug (NSAID) photodegradation. Four Fe-based catalysts and two pristine biochars were obtained upon a pyrolysis process at 500 and 700 °C and fully characterised. Due to the applied synthesis, iron is present in the form of isotropic grains of magnetite (Fe₃O₄), quite homogeneously dispersed onto the biochar. The textural properties of all the materials are mainly determined by the pyrolytic temperature, which results in macroporous materials at 500 °C and microporous ones at 700 °C. Fe-based catalysts were tested in Diclofenac (DFC) photodegradation. DFC removal was the result of both adsorption and photocatalytic reactions. Despite the good yield in DFC removal (80–100%), the formation of degradation by-products can partially invalidate the good effectiveness of this approach. However, the encouraging results of this study represent a step forward for the possible development of waste-derived biochar-based catalysts for in-field application. Full article

(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)

► Show Figures

Figure 1

30 pages, 4630 KiB

Open AccessArticle

Moderate-Temperature Carbon Capture Using Thermally Pre-Treated Dolomite: A Novel Approach

by Iyiade G. Alalade, Javier E. Morales-Mendoza, Alma B. Jasso-Salcedo, Jorge L. Domínguez-Arvizu, Blanca C. Hernández-Majalca, Hammed A. Salami, José L. Bueno-Escobedo, Luz I. Ibarra-Rodriguez, Alejandro López-Ortiz and Virginia H. Collins-Martínez

C 2025, 11(2), 37; https://doi.org/10.3390/c11020037 - 5 Jun 2025

Abstract

This study investigates a novel approach to moderate-temperature carbon capture by examining the enhanced performance of thermally pre-treated dolomite. To obtain mixed oxides, dolomite samples were prepared via calcination in a quartz cylindrical furnace under an ambient atmosphere at 900 °C, and subsequently [...] Read more.

This study investigates a novel approach to moderate-temperature carbon capture by examining the enhanced performance of thermally pre-treated dolomite. To obtain mixed oxides, dolomite samples were prepared via calcination in a quartz cylindrical furnace under an ambient atmosphere at 900 °C, and subsequently thermally pre-treated under an inert (argon) stream at 650 °C. Characterization of the as-prepared samples involved morphological, structural, textural, and optical features examined through XRD, BET, SEM-EDS, FT-IR, and RAMAN, XPS, and UV-vis spectroscopy, whereas TGA and subsequent multicyclic tests were used to study the CO₂ sorption. The dolomite sample calcined at 900 °C for 60 min, and after being activated under an inert atmosphere (argon), labeled PCD60Act, exhibited the highest CO₂ uptake of 0.477 g_CO2/g_sorbent; after 15 sorption–regeneration cycles, it still retained a CO₂ uptake of 0.38 g_CO2/g_sorbent at 650 °C, and it was also successfully regenerated at this moderate temperature, demonstrating 84% capture capacity retention. These remarkable results are explained by the crystalline defects generated during the thermal pre-treatments of the dolomite. This research offers valuable perspectives on the viability of employing thermally pre-treated dolomite as an inexpensive, thermally stable, and moderate-temperature regenerable CaO-based sorbent for applications in CO₂ removal in the context of integrated carbon capture and conversion (ICCC) for the production of high-purity hydrogen. Full article

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

► Show Figures

Graphical abstract

18 pages, 3754 KiB

Open AccessArticle

N, S-Doped Carbon Dots (N, S-CDs) for Perfluorooctane Sulfonic Acid (PFOS) Detection

by Hani Nasser Abdelhamid

C 2025, 11(2), 36; https://doi.org/10.3390/c11020036 - 29 May 2025

Abstract

Nitrogen and sulfur-co-doped carbon dots (N, S-CDs) were synthesized using a simple, eco-friendly hydrothermal technique with L-cysteine as the precursor. The synthesis approach produced highly water-dispersible, heteroatom-doped CDs with surface functional groups comprising amine, carboxyl, thiol, and sulfonic acid. Data analysis of X-ray [...] Read more.

Nitrogen and sulfur-co-doped carbon dots (N, S-CDs) were synthesized using a simple, eco-friendly hydrothermal technique with L-cysteine as the precursor. The synthesis approach produced highly water-dispersible, heteroatom-doped CDs with surface functional groups comprising amine, carboxyl, thiol, and sulfonic acid. Data analysis of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) confirmed their amorphous nature, nanoscale dimensions (1–8 nm, average particle size of 2.6 nm), and surface chemistry. Optical examination revealed intense and pure blue fluorescence emission under UV excitation, with excitation-dependent emission behavior attributed to surface defects and heteroatom doping. The N, S-CDs were applied as fluorescent probes for detecting perfluorooctanesulfonic acid (PFOS), a notable component of the perfluoroalkyl substances (PFAS) family, demonstrating pronounced and concentration-dependent fluorescence quenching. A linear detection range of 3.33–20 µM and a limit of detection (LOD) of 2 µM were reported using the N, S-CDs probe. UV-Vis spectral shifts and dye-interaction investigations indicated that the sensing mechanism is regulated by non-covalent interactions, primarily electrostatic and hydrophobic forces. These findings confirm the potential of N, S-CDs to be used as effective optical sensors for detecting PFOS in environmental monitoring applications. Full article

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

► Show Figures

Graphical abstract

47 pages, 2999 KiB

Open AccessReview

Advances in the Synthesis of Carbon Nanomaterials Towards Their Application in Biomedical Engineering and Medicine

by Numair Elahi and Constantinos D. Zeinalipour-Yazdi

C 2025, 11(2), 35; https://doi.org/10.3390/c11020035 - 20 May 2025

Cited by 1

Abstract

Carbon nanomaterials that include different forms such as graphene, carbon nanotubes, fullerenes, graphite, nanodiamonds, carbon nanocones, amorphous carbon, as well as porous carbon, are quite distinguished by their unique structural, electrical, and mechanical properties. This plays a major role in making them pivotal [...] Read more.

Carbon nanomaterials that include different forms such as graphene, carbon nanotubes, fullerenes, graphite, nanodiamonds, carbon nanocones, amorphous carbon, as well as porous carbon, are quite distinguished by their unique structural, electrical, and mechanical properties. This plays a major role in making them pivotal in various medical applications. The synthesis methods used for such nanomaterials, including techniques such as chemical vapor deposition (CVD), arc discharge, laser ablation, and plasma-enhanced chemical vapor deposition (PECVD), are able to offer very precise control over material purity, particle size, and scalability, enabling for nanomaterials catered for different specific applications. These materials have been explored in a range of different systems, which include drug-delivery systems, biosensors, tissue engineering, as well as advanced imaging techniques such as MRI and fluorescence imaging. Recent advancements, including green synthesis strategies and novel innovative approaches like ultrasonic cavitation, have improved both the precision as well as the scalability of carbon nanomaterial production. Despite challenges like biocompatibility and environmental concerns, these nanomaterials hold immense promise in revolutionizing personalized medicine, diagnostics, and regenerative therapies. Many of these applications are currently positioned at Technology Readiness Levels (TRLs) 3–4, with some systems advancing toward preclinical validation, highlighting their emerging translational potential in clinical settings. This review is specific in evaluating synthesis techniques of different carbon nanomaterials and establishing their modified properties for use in biomedicine. It focuses on how these techniques establish biocompatibility, scalability, and performance for use in medicines such as drug delivery, imaging, and tissue engineering. The implications of nanostructure behavior in biological environments are further discussed, with emphasis on applications in imaging, drug delivery, and biosensing. Full article

(This article belongs to the Special Issue Carbon Nanohybrids for Biomedical Applications (2nd Edition))

► Show Figures

Graphical abstract

21 pages, 1460 KiB

Open AccessArticle

The Application of a Multidisciplinary Framework for Optimizing the Monitoring System for Geological CO₂ Storage

by Yngve Heggelund, Martha Lien and Danny Otto

C 2025, 11(2), 34; https://doi.org/10.3390/c11020034 - 17 May 2025

Abstract

The technical objective of a monitoring system is to provide the means to detect potential irregularities related to the project plan, to provide assurance that the migration of the CO₂ plume stays within the storage unit, and to show that CO₂ [...] Read more.

The technical objective of a monitoring system is to provide the means to detect potential irregularities related to the project plan, to provide assurance that the migration of the CO₂ plume stays within the storage unit, and to show that CO₂ behaves in conformance with the model predictions. From an operational point of view, monitoring will also provide data that can be used to optimize the injection schedule relative to the storage capacity and availability of CO₂ to minimize risks and long-term costs. Finally, monitoring is a crucial factor for the public perception of risks related to CO₂ storage, as surveys indicate that adequately designed monitoring can mitigate concerns. The Analytical Hierarchy Process (AHP) is a holistic, transdisciplinary, multi-criteria decision-making framework. The objective of this work is to apply the AHP framework to monitoring-solutions for a synthetic geological storage site of CO₂ to secure the technical, operational, and societal embeddedness of the solutions and gain experience in how this can be applied to a real project. Through this first application of AHP within the field of geological carbon storage, the AHP was found to be a structured and transparent framework for holistic, multi-criteria decision-making (MCDM), where the wisdom and expertise of different domain experts were considered. A further novelty in this study is introducing a measure of spread in assessing the various solution alternatives’ capacity to meet monitoring criteria. This approach was utilized to underscore disparities among respondents’ experiences and to identify potential informational deficiencies in evaluating alternatives and devising the optimal monitoring solution. Full article

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

► Show Figures

Figure 1

10 pages, 3906 KiB

Open AccessArticle

Graphite-like C₃N₄ and Graphene Oxide Co-Enhanced the Photocatalytic Activity of ZnO Under Natural Sunlight

by Huan Chen, Shengfeng Chen, Qun Fang and Chuansheng Chen

C 2025, 11(2), 33; https://doi.org/10.3390/c11020033 - 6 May 2025

Abstract

To enhance the photocatalytic performance of ZnO, the ZnO/g-C₃N₄ (ZCN) composite was prepared by ZnO and g-C₃N₄ under ball milling, and then the ternary graphene oxide (GO)/ZnO/g-C₃N₄ (GZCN) composite was achieved by using sonicating, [...] Read more.

To enhance the photocatalytic performance of ZnO, the ZnO/g-C₃N₄ (ZCN) composite was prepared by ZnO and g-C₃N₄ under ball milling, and then the ternary graphene oxide (GO)/ZnO/g-C₃N₄ (GZCN) composite was achieved by using sonicating, stirring, and liquid phase evaporating. The photocatalytic performance was tested under UV light and natural solar light, respectively. The experimental results displayed that the GZCN composite revealed excellent photocatalytic performance under UV light and natural sunlight. When the ratio of ZnO to g-C₃N₄ is 1:0.2 and the mass fraction of graphene oxide is 0.25% in GZCN composite, the modified ZnO possesses optimal photocatalytic activity under UV light or natural solar light. RhB dye is degraded by 94% within 20 min under UV light, which is 3.41 times that of pure ZnO. Moreover, GZCN can degrade 88% of RhB in 60 min under natural sunlight. The enhancement for photocatalytic activity is attributed to the excellent conductivity of GO and heterojunction interaction between ZnO and g-C₃N₄, where the special electronic structure of g-C₃N₄ expands the spectral response range of ZnO and accelerates the transmission of photogenerated electrons and holes. Full article

(This article belongs to the Special Issue Advanced Graphene and g-C₃N₄-Based Photocatalysts for Energy Conversion)

► Show Figures

Graphical abstract

13 pages, 2893 KiB

Open AccessArticle

Fabrication of Wood-Derived Carbon Aerogel/Mg(OH)₂ Bio-Composite and Its High Performance for Adsorption and Separation of Cadmium Ions

by Ran An, Jinyue Liu, Haomiao Ma, Yuqing Yan, Yuanru Guo, Qingjiang Pan and Shujun Li

C 2025, 11(2), 32; https://doi.org/10.3390/c11020032 - 6 May 2025

Abstract

To address the need for reducing carbon emissions and enhancing the sustainable utilization of non-fossil resources, a one-step calcination strategy has been developed to fabricate hierarchical carbon aerogels from balsa wood. The resulting wood-derived carbon aerogels (WCA) were functionalized with Mg(OH)₂ to [...] Read more.

To address the need for reducing carbon emissions and enhancing the sustainable utilization of non-fossil resources, a one-step calcination strategy has been developed to fabricate hierarchical carbon aerogels from balsa wood. The resulting wood-derived carbon aerogels (WCA) were functionalized with Mg(OH)₂ to boost their environmental remediation potential. Comprehensive characterization using XRD, FT-IR, XPS, and SEM confirmed that the optimized WCA/Mg(OH)₂ composite (WCAMg) retained a three-dimensional hierarchical porous structure, and Mg(OH)₂ nanosheets were attached to it. The adsorption performance of WCAMg composites towards Cd²⁺ was systematically investigated through controlled experiments, which focused on three critical variables (Mg(OH)₂ loading content, initial Cd²⁺ concentration and solution ionic strength). The functionalized WCAMg demonstrated a maximum Cd²⁺ adsorption capacity of 351.1 mg g⁻¹—a tenfold improvement over pristine WCA. Combined with exceptional adsorption efficiency, this biomass-derived composite offers an eco-friendly, cost-effective solution for heavy metal ion remediation. Its scalable fabrication from renewable resources aligns with sustainable water treatment objectives, presenting the advantage of pollution mitigation. Full article

(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)

► Show Figures

Graphical abstract

11 pages, 4734 KiB

Open AccessArticle

Electron Beam-Irradiated Cross-Linked Polyethylene Composites Containing Graphene Nanoplatelets for Thermally Conducting Pipes

by Wenge Xu, Kuan Lu, Huinan Li, Chen Xiong, Yang Liu and Baijun Liu

C 2025, 11(2), 31; https://doi.org/10.3390/c11020031 - 4 May 2025

Abstract

In this study, some polyethylene/graphene nanoplatelet (PE-GE) composites are successfully prepared via a melt-blending process used for thermally conductive pipes. A comparison study on the effect of different fillers (i.e., graphene nanoplatelet and aluminum oxide) on thermal conductivity is conducted. The conductivity was [...] Read more.

In this study, some polyethylene/graphene nanoplatelet (PE-GE) composites are successfully prepared via a melt-blending process used for thermally conductive pipes. A comparison study on the effect of different fillers (i.e., graphene nanoplatelet and aluminum oxide) on thermal conductivity is conducted. The conductivity was over 2.5 W/m·K when 30 fractions of GE were involved. Furthermore, an electron beam irradiation technology is utilized to obtain the cross-linked composite materials with excellent comprehensive performance. The relationships between thermal conductivity and filler content, and irradiation dose and gel content have been carefully investigated. Finally, a polyethylene/graphene composite with 0.72 W/m·K is used to extrude a pipe, which exhibits some attractive properties for floor heating pipes. Full article

(This article belongs to the Special Issue Carbon-Based Polymer Composites: Synthesis, Processing, Characterization and Applications)

► Show Figures

Graphical abstract

19 pages, 3581 KiB

Open AccessArticle

Innovative X-Ray Absorption Technology for Improved Monitoring of the Degradation and Oxidation of Granular Activated Carbon Filters Used in Hospital Water Treatment Systems

by Jeamichel Puente Torres, Harold Crespo Sariol, Thayset Mariño Peacok, Tom Haeldermans, Guy Reggers, Jan Yperman, Peter Adriaensens, Robert Carleer and Dries Vandamme

C 2025, 11(2), 30; https://doi.org/10.3390/c11020030 - 28 Apr 2025

Abstract

This study introduces a novel, non-invasive X-ray absorption analysis (XRA) method to evaluate the photonic absorption process of granular activated carbon (GAC) in hospital water purification systems. By leveraging digital radiographic images, this innovative technique monitors the deterioration and oxidation of the GAC [...] Read more.

This study introduces a novel, non-invasive X-ray absorption analysis (XRA) method to evaluate the photonic absorption process of granular activated carbon (GAC) in hospital water purification systems. By leveraging digital radiographic images, this innovative technique monitors the deterioration and oxidation of the GAC filter, predicts its remaining lifetime, and estimates its water dechlorinating capacity. Analyzing the entire GAC filter and making a reuse possible, the new XRA method provides valuable insights into the filter’s condition, enhancing water purification efficiency and costs without analyzing subsamples. Complementary analytical techniques on subsamples, taken at various depths, did not yield valuable additional information of the GAC filter exhaustion condition, nor additionally make a reuse impossible. Full article

(This article belongs to the Special Issue Carbon-Based Materials Applied in Water and Wastewater Treatment)

► Show Figures

Figure 1

16 pages, 4882 KiB

Open AccessArticle

Experimental Investigation of Use of Monoethanolamine with Iron Oxide Nanoparticles in a 10 kg per Day Pilot CO₂ Capture Plant: Implications for Commercialization

by Sriniwasa Prabhu, Govindaradjane Soupramaniane and Raman Saravanane

C 2025, 11(2), 29; https://doi.org/10.3390/c11020029 - 27 Apr 2025

Abstract

This study explores enhancements in CO₂ capture and release using monoethanolamine (MEA) combined with iron oxide nanoarticles (IONPs) in a 10 kg per day pilot CO₂ capture plant. Previous studies highlighted the potential of nanoparticle additives to improve CO₂ capture [...] Read more.

This study explores enhancements in CO₂ capture and release using monoethanolamine (MEA) combined with iron oxide nanoarticles (IONPs) in a 10 kg per day pilot CO₂ capture plant. Previous studies highlighted the potential of nanoparticle additives to improve CO₂ capture via modeling and batch experiments; however, robust experimental evidence at the pilot scale is necessary for commercialization. This pilot plant employed a thermal swing process using synthetic CO₂–flue gas mixtures, conditioning systems, and Programmable Logic Controller (PLC)-based controls for heating, operation, and data acquisition. IONPs, synthesized through chemical precipitation and characterized by XRD and HR-SEM, were integrated into MEA at concentrations of 0.0001% w/v (1 ppm), 0.001% w/v (10 ppm), and 0.002% w/v (20 ppm). Their electromagnetic properties enhanced mass transfer during absorption and significantly reduced heat demand during stripper desorption. Higher concentrations of IONPs decreased desorption temperatures by up to 7 °C, resulting in estimated energy savings of approximately 10–15%, while achieving CO₂ loading rates up to 0.34 mol CO₂/mol MEA. Structural stability of the IONPs was confirmed via XRD and HR-SEM analyses following extended thermal cycling. Utilizing a common solvent and abundant catalyst, these demonstrated improvements underscore the practical scalability and commercial viability of MEA-based CO₂ capture catalyzed by IONPs, particularly suitable for deployment in large-scale CO₂ capture systems in high-CO₂-emitting industries. Full article

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

► Show Figures

Graphical abstract

28 pages, 4940 KiB

Open AccessReview

Plasma-Modified Carbon Materials for Radionuclide Absorption

by Yifan Fang, Zixuan Guo, Bing Lian, Jing Kang, Zhou Fang, Longfei Qie, Lili Liu, Luxiang Zhao and Ruixue Wang

C 2025, 11(2), 28; https://doi.org/10.3390/c11020028 - 22 Apr 2025

Abstract

Carbon-based materials, characterized by their high specific surface area and exceptional chemical stability, have become integral to adsorption-based remediation methods. Carbon materials demonstrate exceptional efficiency, selectivity, and environmental compatibility in radionuclide adsorption. However, the practical application of conventional carbon materials is limited by [...] Read more.

Carbon-based materials, characterized by their high specific surface area and exceptional chemical stability, have become integral to adsorption-based remediation methods. Carbon materials demonstrate exceptional efficiency, selectivity, and environmental compatibility in radionuclide adsorption. However, the practical application of conventional carbon materials is limited by their insufficient adsorption capacity and selectivity. Plasma modification has emerged as a highly effective strategy for enhancing the surface chemistry of carbon materials, thereby significantly improving their adsorption performance. This process increases the specific surface area of carbon materials and introduces a variety of functional groups, which in turn boost their capacity to adsorb radionuclides. This review systematically explores the progress made in modifying carbon-based adsorbents for the remediation of radioactive nuclides, with a particular emphasis on the mechanisms and effectiveness of plasma modification, covering studies on plasma-modified carbon materials for radionuclide adsorption published between 2009 and 2024. Furthermore, the review discusses the future prospects and practical applications of plasma-modified carbon materials in nuclear wastewater treatment, providing a scientific foundation for the development of efficient and sustainable remediation technologies. Full article

(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)

► Show Figures

Graphical abstract

16 pages, 2472 KiB

Open AccessArticle

Green Synthesis of a Highly Active Ag/Activated Carbon Nanocomposite from Tamarind Seeds for Methyl Orange Removal

by Samah Daffalla, Nura Al Mousa, Hussain Ahmed, Jana Alsuwailem, Mustafa I. Almaghasla and Mohamed R. El-Aassar

C 2025, 11(2), 27; https://doi.org/10.3390/c11020027 - 17 Apr 2025

Abstract

This study investigated the enhanced adsorption capacity of a silver nanoparticle (AgNPs)-incorporated tamarind seed activated carbon nanocomposite (Ag/TSAC) for the elimination of methyl orange (MO) from aqueous solutions. The nanocomposite was analyzed using TGA, SEM, FTIR, and BET, revealing a mesoporous structure with [...] Read more.

This study investigated the enhanced adsorption capacity of a silver nanoparticle (AgNPs)-incorporated tamarind seed activated carbon nanocomposite (Ag/TSAC) for the elimination of methyl orange (MO) from aqueous solutions. The nanocomposite was analyzed using TGA, SEM, FTIR, and BET, revealing a mesoporous structure with a surface area of 54.92 m²/g. The results showed that the structure of tamarind seeds altered during pyrolysis, as shown by the loss of many functional groups and a weight decrease of 66.61% in the nanocomposite. The efficiency of the nanocomposite in eliminating MO was assessed by batch adsorption studies, which also examined the effects of solution pH, starting MO concentration, and nanocomposite dose. The best MO removal was seen at pH 2, indicating a positive electrostatic interaction between the dye and adsorbent. The results demonstrated that the Ag/TSAC nanocomposite significantly enhanced MO removal efficiency from 19% to 96% under optimal adsorptive conditions, due to the synergistic effect of the high surface area of activated carbon and the enhanced adsorption sites provided by the AgNPs. The study demonstrates the potential of Ag/activated carbon nanocomposite as a sustainable adsorbent for removing MO dye from wastewater using a second-order model and Langmuir model. Full article

(This article belongs to the Special Issue Carbon Functionalization: From Synthesis to Applications)

► Show Figures

Graphical abstract

Journal Description

C — Journal of Carbon Research

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI