C | An Open Access Journal from MDPI

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)

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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)

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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)

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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)

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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)

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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)

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12 pages, 19666 KiB

Open AccessArticle

Modulation of Giant Magnetoimpedance Effect in Co-Based Amorphous Wires by Carbon-Based Nanocoatings

by Zhen Yang, Jiabao Huang, Jingyuan Chen and Chong Lei

C 2025, 11(2), 26; https://doi.org/10.3390/c11020026 - 1 Apr 2025

Abstract

Co-based amorphous wires (Co-AWs) are functional materials renowned for their high impedance change rate in magnetic fields and a pronounced giant magnetoimpedance (GMI) effect. In this study, magnetron sputtering (MS) and dip-coating (DC) techniques were employed to fabricate carbon-based nanocoatings aimed at modulating [...] Read more.

Co-based amorphous wires (Co-AWs) are functional materials renowned for their high impedance change rate in magnetic fields and a pronounced giant magnetoimpedance (GMI) effect. In this study, magnetron sputtering (MS) and dip-coating (DC) techniques were employed to fabricate carbon-based nanocoatings aimed at modulating the GMI properties of Co-AWs. The magnetic properties and GMI responses of the composite Co-AWs with carbon-based coatings were comparatively analyzed. The results demonstrate that both methods effectively enhanced the GMI properties of the coated Co-AWs. The DC method emerged as a rapid and efficient approach for forming the coated film, achieving a modest enhancement in GMI performance (10% enhancement). In contrast, the MS technique proved more effective in improving the GMI effect, yielding superior results. Co-AWs coated via Ms exhibited smoother surfaces and reduced coercivity. Notably, the GMI effect increased with the thickness of the sputtered carbon coatings, reaching a maximum GMI effect of 522% (a remarkable 357% enhancement) and a sensitivity of 33.8%/Oe at a coating thickness of 334 nm. The observed trend in the GMI effect with carbon layer thickness corresponded closely to variations in transverse permeability, as determined by vibrating sample magnetometry (VSM). Furthermore, the carbon coating induced changes in the initial quenching stress on the surface of the Co-AWs, leading to alterations in impedance and a significant reduction in the characteristic frequency of the Co-AWs. Our findings provide valuable insights into the modulation of GMI properties in Co-AWs, paving the way for their optimized application in advanced magnetic sensor technologies. Full article

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

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19 pages, 4792 KiB

Open AccessArticle

Conversion of Carbon Dioxide into Solar Fuels Using MgFe₂O₄ Thermochemical Redox Chemistry

by Rahul R. Bhosale

C 2025, 11(2), 25; https://doi.org/10.3390/c11020025 - 25 Mar 2025

Abstract

Transforming H₂O and CO₂ into solar fuels like syngas is crucial for future sustainable transportation fuel production. Therefore, the MgFe₂O₄/CO₂ splitting cycle was thermodynamically scrutinized to estimate its solar-to-fuel energy conversion efficiency in this investigation. [...] Read more.

Transforming H₂O and CO₂ into solar fuels like syngas is crucial for future sustainable transportation fuel production. Therefore, the MgFe₂O₄/CO₂ splitting cycle was thermodynamically scrutinized to estimate its solar-to-fuel energy conversion efficiency in this investigation. The thermodynamic data required to solve the modeling equations were obtained using the HSC Chemistry program. The reduction non-stoichiometry was assumed to be equal to 0.1 for all computations. One of the study’s primary goals was to examine the impact of the inert sweep gas’s molar flow rate on the process parameters related to the MgFe₂O₄/CDS cycle. Overall, it was understood that the effect of the inert sweep gas’s molar flow rate on the thermal reduction temperature was significant when it increased from 10 to 40 mol/s compared to the rise from 40 to 100 mol/s. The energy needed to reduce MgFe₂O₄ increased slightly due to the surge in the inert sweep gas’s molar flow rate. In contrast, the energy penalty for heating MgFe₂O_4-δred from the re-oxidation to thermal reduction temperature significantly decreased. Including gas-to-gas heat exchangers with a gas-to-gas heat recovery effectiveness equal to 0.5 helped reduce the energy demand for heating the inert sweep gas. Overall, although the rise in the inert sweep gas’s molar flow rate from 10 to 100 mol/s caused a drop in the thermal reduction temperature by 180 K, the total solar energy needed to drive the cycle was increased by 85.7 kW. Accordingly, the maximum solar-to-fuel energy conversion efficiency (13.1%) was recorded at an inert sweep gas molar flow rate of 10 mol/s, which decreased by 3.7% when it was increased to 100 mol/s. Full article

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

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18 pages, 21154 KiB

Open AccessArticle

Preparation of CCF/MWCNT-OH/Graphite/Resin Composite Bipolar Plates Using Bi-Directional Interfacial Modification and Study of Their Performance Improvement and the Mechanism of Their Interfacial Bonding Improvement

by Wenkai Li, Haodong Zeng and Zhiyong Xie

C 2025, 11(1), 24; https://doi.org/10.3390/c11010024 - 19 Mar 2025

Abstract

Composite bipolar plates are a new class of material bipolar plates for PEMFCs. However, their application is limited by problems such as the difficulty of balancing their strength/conductivity properties. In this paper, by using surface-modified carboxylated short-cut carbon fibers and hydroxylated carbon nanotubes [...] Read more.

Composite bipolar plates are a new class of material bipolar plates for PEMFCs. However, their application is limited by problems such as the difficulty of balancing their strength/conductivity properties. In this paper, by using surface-modified carboxylated short-cut carbon fibers and hydroxylated carbon nanotubes as well as PI resin, the interfacial bonding between the carbon-based filler and the resin is effectively improved under the premise of ensuring electrical conductivity, which enhances the flexural strength. The effect of the surface modification of the filler on the interfacial bonding between the filler and the PI resin is thoroughly investigated through molecular dynamics simulations. The mechanism for this improved bonding was also studied. Through the surface modification of the filler, the composite bipolar plates possessed a flexural strength of 49.06 MPa and a planar conductivity of 228.52 S/cm with the addition of 6% MWCNT-OH as well as 12% CCFs, which has the potential to be an optional substrate for composite bipolar plates. Full article

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

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8 pages, 2405 KiB

Open AccessCommunication

One-Pot Bottom-Up Synthesis of SiO₂ Quantum Dots and Reduced Graphene Oxide (rGO) Nanocomposite as Anode Materials in Lithium-Ion Batteries

by Sanjaya Brahma, Cheung-Yi Wang, Yi-Hsuan Huang, Wen-Feng Lin and Jow-Lay Huang

C 2025, 11(1), 23; https://doi.org/10.3390/c11010023 - 10 Mar 2025

Abstract

Here, crystalline SiO₂ quantum dots (QDs) of 3–5 nm size were grown within the layers of reduced graphene oxide (rGO) by a solution mode chemical growth process at a relatively low temperature (100 °C). The composite was applied as a negative electrode [...] Read more.

Here, crystalline SiO₂ quantum dots (QDs) of 3–5 nm size were grown within the layers of reduced graphene oxide (rGO) by a solution mode chemical growth process at a relatively low temperature (100 °C). The composite was applied as a negative electrode in a Li-ion half-cell battery and the electrochemical investigation confirmed a distinct first-cycle discharge/charge capacity (~865 mAhg⁻¹/387 @ 51 mAg⁻¹). The battery could retain a capacity of 296 mAhg⁻¹ after 60 charge/discharge cycles with 99% coulombic efficiency. Furthermore, at a high current rate of 1.02 Ag⁻¹, the battery was able to display an apparent rate capability (214.47 mAhg⁻¹), indicating the high chemical and mechanical stability of the composite at a high current rate. A structural analysis revealed clear distinct diffraction peaks of SiO₂ and high-resolution transmission electron microscopy images showed discrete atomic planes, thereby confirming the growth of crystalline SiO₂ QDs within the layers of rGO. Full article

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

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18 pages, 3950 KiB

Open AccessArticle

Environmental Impacts and Adsorption Isotherms of Coconut Shell Activated Carbon: Effect of Acid Activation, Water, and Fuel

by Junaid Saleem, Zubair Khalid Baig Moghal, Furqan Tahir, Tareq Al-Ansari and Gordon McKay

C 2025, 11(1), 22; https://doi.org/10.3390/c11010022 - 10 Mar 2025

Abstract

Activated biomass has gained interest as an alternative to coal-based activated carbon (AC). This work investigates the environmental impact (EI) of coconut shell (CS)-derived AC as a substitute for non-renewable coal-based AC. The AC was produced in-house using tandem acid activation and pyrolysis, [...] Read more.

Activated biomass has gained interest as an alternative to coal-based activated carbon (AC). This work investigates the environmental impact (EI) of coconut shell (CS)-derived AC as a substitute for non-renewable coal-based AC. The AC was produced in-house using tandem acid activation and pyrolysis, employing two activation pathways: sulfuric acid (H₂SO₄) and phosphoric acid (H₃PO₄). This study further investigates the impact of activation routes, fuel types, and water sources on environmental outcomes. This evaluation focuses on six key impacts: climate change, fossil depletion, freshwater ecotoxicity, freshwater eutrophication, land use, and energy net. The H₂SO₄ activation pathway is more favorable in terms of EI due to its lower net energy requirement (27.2 MJ) and reduced carbon emissions (1.2 kg CO₂ eq.). However, it requires 4.7 kg of AC to adsorb 1 kg of dye, whereas the H₃PO₄ pathway requires only 4.3 kg. Therefore, while the H₃PO₄ pathway may be preferred for applications needing higher adsorption capacities, the H₂SO₄ pathway offers a more environmentally benign option, highlighting the trade-offs in selecting an activation method for AC production. Additionally, this study highlights that CS-derived AC offers substantial energy savings of 78%, alongside a 75% reduction in carbon emissions and an 80% decrease in fossil depletion compared to coal-based AC. Overall, the synthesized AC shows promise as a sustainable alternative to coal-based counterparts. Full article

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

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5 pages, 228 KiB

Open AccessEditorial

Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties

by Gil Gonçalves

C 2025, 11(1), 21; https://doi.org/10.3390/c11010021 - 8 Mar 2025

Abstract

Carbon materials have played a pivotal role in humanity’s progress since ancient times [...] Full article

(This article belongs to the Collection Nanocarbon-Based Composites and Their Thermal, Electrical, and Mechanical Properties)

21 pages, 5290 KiB

Open AccessArticle

Historical Drivers and Reduction Paths of CO₂ Emissions in Jiangsu’s Cement Industry

by Kuanghan Sun, Jian Sun, Changsheng Bu, Long Jiang and Chuanwen Zhao

C 2025, 11(1), 20; https://doi.org/10.3390/c11010020 - 5 Mar 2025

Abstract

With global climate challenges intensifying, the cement industry, as a major CO₂ emitter, has attracted significant attention regarding its emission reduction potential and strategies. Advanced economies like the European Union use carbon pricing to spur innovation, while emerging countries focus on incremental [...] Read more.

With global climate challenges intensifying, the cement industry, as a major CO₂ emitter, has attracted significant attention regarding its emission reduction potential and strategies. Advanced economies like the European Union use carbon pricing to spur innovation, while emerging countries focus on incremental solutions, such as fuel substitution. Combining LMDI decomposition and the LEAP model, this study examines Jiangsu Province as a test bed for China’s decarbonization strategy, a highly efficient region with carbon intensity 8% lower than the national average. Historical analysis identifies carbon intensity, energy mix, energy intensity, output scale, and economic effects as key drivers of emission changes. Specifically, the reduction in cement production, real estate contraction, lower housing construction, and reduced production capacity are the main factors curbing emissions. Under an integrated technology strategy—including energy efficiency, fuel and clinker substitution, and CCS—CO₂ emissions from Jiangsu’s cement sector are projected to decrease to 17.28 million tons and 10.9 million tons by 2060 under high- and low-demand scenarios, respectively. Clinker substitution is the most significant CO₂ reduction technology, contributing about 60%, while energy efficiency gains contribute only 3.4%. Despite the full deployment of existing reduction methods, Jiangsu’s cement industry is expected to face an emissions gap of approximately 10 million tons to achieve carbon neutrality by 2060, highlighting the need for innovative emission reduction technologies or carbon trading to meet carbon neutrality goals. Full article

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

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22 pages, 10051 KiB

Open AccessArticle

Reuse of Activated Carbons from Filters for Water Treatment Derived from the Steam Cycle of a Nuclear Power Plant

by Beatriz Ledesma Cano, Eva M. Rodríguez, Juan Félix González González and Sergio Nogales-Delgado

C 2025, 11(1), 19; https://doi.org/10.3390/c11010019 - 3 Mar 2025

Abstract

Nuclear energy has a great impact on the global energy mix. In Spain, it supplies over 20% of current energy requirements, demonstrating the relevance of nuclear power plants. These plants generate different types of waste (apart from radioactive) that should be managed. For [...] Read more.

Nuclear energy has a great impact on the global energy mix. In Spain, it supplies over 20% of current energy requirements, demonstrating the relevance of nuclear power plants. These plants generate different types of waste (apart from radioactive) that should be managed. For instance, the activated carbon included in filters (which neutralize isotopes in a possible radioactive leakage) should be periodically replaced. Nevertheless, these activated carbons might present long service lives, as they have not undergone any adsorption processes. Consequently, a considerable amount of activated carbon can be reused in alternative processes, even in the same nuclear power plant. The aim of this work was to assess the use of activated carbons (previously included in filters to prevent possible radioactive releases in primary circuits) for water treatment derived from the steam cycle of a nuclear power plant. A regeneration process (boron removal) was carried out (with differences between untreated carbon and after treatments, from S_BET = 684 m² g⁻¹ up to 934 m² g⁻¹), measuring the adsorption efficiency for ethanolamine and triton X-100. There were no significative results that support the adsorption effectiveness of the activated carbon tested for ethanolamine adsorption, whereas a high adsorption capacity was found for triton X-100 (q_L1 = 281 mg·g⁻¹), proving that factors such as porosity play an important role in the specific usage of activated carbons. Full article

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

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17 pages, 4652 KiB

Open AccessArticle

A New Monohydrogen Phosphate-Selective Carbon Composite Membrane Electrode for Soil Water Samples

by Ozlem Tavukcuoglu, Vildan Erci, Fatih Ciftci, Ibrahim Isildak and Muhammed Zahid Kasapoglu

C 2025, 11(1), 18; https://doi.org/10.3390/c11010018 - 1 Mar 2025

Abstract

This study focused on developing a novel composite phosphate-selective electrode for on-site and real-time applications using a silver polyglutaraldehyde phosphate and carbon nanotube (CNT) matrix. CNT-silver polyglutaraldehyde phosphate compound was synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray [...] Read more.

This study focused on developing a novel composite phosphate-selective electrode for on-site and real-time applications using a silver polyglutaraldehyde phosphate and carbon nanotube (CNT) matrix. CNT-silver polyglutaraldehyde phosphate compound was synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The potentiometric performance of the composite phosphate-selective electrode was then investigated. The results demonstrated that the composite phosphate-selective electrode exhibited good sensitivity, with a linear response in the concentration range of 1.0 × 10⁻⁴ to 1.0 × 10⁻² M for phosphate ions. The electrode also showed high selectivity towards phosphate ions compared to other anions, such as chloride and nitrate. Additionally, the electrode displayed a quick response time of less than 15 s, making it suitable for real-time measurements. The electrode was applied to surface and soil water samples. The results obtained from the water samples showed a strong correlation with those obtained from the preferred spectrophotometry method, highlighting the potential of the developed electrode for on-site and continuous monitoring of phosphate and offering an efficient and practical solution for various fields that require phosphate detection. Full article

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

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15 pages, 10623 KiB

Open AccessArticle

Optical Transitions Dominated by Orbital Interactions in Two-Dimensional Fullerene Networks

by Haonan Bai, Xinwen Gai, Yi Zou and Jingang Wang

C 2025, 11(1), 17; https://doi.org/10.3390/c11010017 - 25 Feb 2025

Abstract

Fullerenes are a class of highly symmetric spherical carbon materials that have attracted significant attention in optoelectronic applications due to their excellent electron transport properties. However, the isotropy of their spherical structure often leads to disordered inter-sphere stacking in practical applications, limiting in-depth [...] Read more.

Fullerenes are a class of highly symmetric spherical carbon materials that have attracted significant attention in optoelectronic applications due to their excellent electron transport properties. However, the isotropy of their spherical structure often leads to disordered inter-sphere stacking in practical applications, limiting in-depth studies of their electron transport behavior. The successful fabrication of long-range ordered two-dimensional fullerene arrays has opened up new opportunities for exploring the structure–activity relationship in spatial charge transport. In this study, theoretical calculations were performed to analyze the effects of different periodic arrangements in two-dimensional fullerene arrays on electronic excitation and optical behavior. The results show that HLOPC₆₀ exhibits a strong absorption peak at 1050 nm, while TLOPC₆₀ displays prominent absorption features at 700 nm and 1300 nm, indicating that their electronic excitation characteristics are significantly influenced by the periodic structure. Additionally, analyses of orbital distribution and the spatial electron density reveal a close relationship between carrier transport and the structural topology. Quantitative studies further indicate that the interlayer interaction energies of the HLOPC₆₀ and TLOPC₆₀ arrangements are −105.65 kJ/mol and −135.25 kJ/mol, respectively. TLOPC₆₀ also exhibits stronger dispersion interactions, leading to enhanced interlayer binding. These findings provide new insights into the structural regulation of fullerene materials and offer theoretical guidance for the design and synthesis of novel organic optoelectronic materials. Full article

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

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17 pages, 51050 KiB

Open AccessArticle

Towards Environmentally Friendly Buildings: An Assessment of the Mechanical Properties of Soil Mixtures with Graphene

by Federico Iorio Esposito, Paola Gallo Stampino, Letizia Ceccarelli, Marco Caruso, Giovanni Dotelli and Sergio Sabbadini

C 2025, 11(1), 16; https://doi.org/10.3390/c11010016 - 19 Feb 2025

Abstract

This study investigates the potential of graphene-based additives to improve the mechanical properties of compacted soil mixtures in rammed-earth construction, contributing to the development of environmentally friendly building materials. Two distinct soils were selected, combined with sand at optimized ratios, and treated with [...] Read more.

This study investigates the potential of graphene-based additives to improve the mechanical properties of compacted soil mixtures in rammed-earth construction, contributing to the development of environmentally friendly building materials. Two distinct soils were selected, combined with sand at optimized ratios, and treated with varying concentrations of a graphene liquid solution and a graphene-based paste (0.001, 0.005, 0.01, 0.05, and 0.1 wt.% relative to the soil-sand proportion). The effects of these additives were analyzed using the modified Proctor compaction and unconfined compressive strength (UCS) tests, focusing on parameters such as optimum water content (OWC), maximum dry density (MDD), maximum strength (q_u), and stiffness modulus (E). The results demonstrated that graphene’s influence on compaction behavior and mechanical performance depends strongly on the soil composition, with minimal variation between additive types. In finer soil mixtures, graphene disrupted particle packing, increased water demand, and reduced strength. In silt–sandy mixtures, graphene’s hydrophobicity and limited interaction with fines decreased water absorption and preserved density but likewise led to diminished strength. Conclusions from the experiments suggest a possible interaction between graphene, soil’s finer fraction, and potentially the swelling and non-swelling clay minerals, providing insights into the complex interplay between soil properties. Full article

(This article belongs to the Topic Application of Graphene-Based Materials, 2nd Edition)

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26 pages, 6250 KiB

Open AccessArticle

Activated Carbon Ammonization: Effects of the Chemical Composition of the Starting Material and the Treatment Temperature

by Silvia da C. Oliveira, Romulo C. Dutra, José J. L. León, Gesley A. V. Martins, Alysson M. A. Silva, Diana C. S. de Azevedo, Rafaelle G. Santiago, Daniel Ballesteros-Plata, Enrique Rodríguez-Castellón and Marcos J. Prauchner

C 2025, 11(1), 15; https://doi.org/10.3390/c11010015 - 19 Feb 2025

Cited by 1

Abstract

N-containing carbon-based materials have been employed with claimed improved performance as an adsorbent of acidic molecules, volatile organic compounds (VOC), and metallic ions; catalyst; electrocatalyst; and supercapacitor. In this context, the present work provides valuable insights into the preparation of N-doped activated carbons [...] Read more.

N-containing carbon-based materials have been employed with claimed improved performance as an adsorbent of acidic molecules, volatile organic compounds (VOC), and metallic ions; catalyst; electrocatalyst; and supercapacitor. In this context, the present work provides valuable insights into the preparation of N-doped activated carbons (ACs) by thermal treatment in NH₃ atmosphere (ammonization). A commercial AC was submitted to two kinds of pretreatment: (i) reflux with dilute HNO₃; (ii) thermal treatment up to 800 °C in inert atmosphere. The original and modified ACs were subjected to ammonization up to different temperatures. ACs with N content up to ~8% were achieved. Nevertheless, the amount and type of inserted nitrogen depended on ammonization temperature and surface composition of the starting material. Remarkably, oxygenated acidic groups on the surface of the starting material favored nitrogen insertion at low temperatures, with formation of mostly aliphatic (amines, imides, and lactams), pyridinic, and pyrrolic nitrogens. In turn, high temperatures provoked the decomposition of labile aliphatic functions. Therefore, the AC prepared from the sample pre-treated with HNO₃, which had the highest content of oxygenated acidic groups among the materials submitted to ammonization, presented the highest N content after ammonization up to 400 °C but the lowest content after ammonization up to 800 °C. Full article

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

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13 pages, 7070 KiB

Open AccessArticle

Porous Polysulfone/Activated Carbon Capsules as Scaffolds for Enzyme Immobilization

by Magdalena Olkiewicz, Josep M. Montornes, Ricard Garcia-Valls, Iwona Gulaczyk and Bartosz Tylkowski

C 2025, 11(1), 14; https://doi.org/10.3390/c11010014 - 17 Feb 2025

Abstract

Enzymes play a vital role in various industrial sectors and are essential components of many products. Hybrid enzyme-polymeric capsules were developed using polysulfone-activated carbon capsules as scaffolds. The polysulfone-activated carbon capsules with an average diameter of 2.55 mm were fabricated by applying a [...] Read more.

Enzymes play a vital role in various industrial sectors and are essential components of many products. Hybrid enzyme-polymeric capsules were developed using polysulfone-activated carbon capsules as scaffolds. The polysulfone-activated carbon capsules with an average diameter of 2.55 mm were fabricated by applying a phase inversion precipitation method. An increase in the amount of immobilized enzymes was observed with growth of activated carbon amount in polysulfone matrix. Enzyme immobilization was confirmed by the Bradford method, while Viscozyme^® L activity in carboxymethyl cellulose hydrolysis to glucose was measured by the Reducing Sugar DNS method. The recycling of the hybrid Viscozyme^® L-polysulfone/activated carbon capsules, and their reuse for subsequent cellulose hydrolysis was investigated and demonstrated repeatability of results. Full article

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

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C — Journal of Carbon Research

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