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25 pages, 77176 KiB  
Article
Advancing Energy Management Strategies for Hybrid Fuel Cell Vehicles: A Comparative Study of Deterministic and Fuzzy Logic Approaches
by Mohammed Essoufi, Mohammed Benzaouia, Bekkay Hajji, Abdelhamid Rabhi and Michele Calì
World Electr. Veh. J. 2025, 16(8), 444; https://doi.org/10.3390/wevj16080444 (registering DOI) - 6 Aug 2025
Abstract
The increasing depletion of fossil fuels and their environmental impact have led to the development of fuel cell hybrid electric vehicles. By combining fuel cells with batteries, these vehicles offer greater efficiency and zero emissions. However, their energy management remains a challenge requiring [...] Read more.
The increasing depletion of fossil fuels and their environmental impact have led to the development of fuel cell hybrid electric vehicles. By combining fuel cells with batteries, these vehicles offer greater efficiency and zero emissions. However, their energy management remains a challenge requiring advanced strategies. This paper presents a comparative study of two developed energy management strategies: a deterministic rule-based approach and a fuzzy logic approach. The proposed system consists of a proton exchange membrane fuel cell (PEMFC) as the primary energy source and a lithium-ion battery as the secondary source. A comprehensive model of the hybrid powertrain is developed to evaluate energy distribution and system behaviour. The control system includes a model predictive control (MPC) method for fuel cell current regulation and a PI controller to maintain DC bus voltage stability. The proposed strategies are evaluated under standard driving cycles (UDDS and NEDC) using a simulation in MATLAB/Simulink. Key performance indicators such as fuel efficiency, hydrogen consumption, battery state-of-charge, and voltage stability are examined to assess the effectiveness of each approach. Simulation results demonstrate that the deterministic strategy offers a structured and computationally efficient solution, while the fuzzy logic approach provides greater adaptability to dynamic driving conditions, leading to improved overall energy efficiency. These findings highlight the critical role of advanced control strategies in improving FCHEV performance and offer valuable insights for future developments in hybrid-vehicle energy management. Full article
(This article belongs to the Special Issue Power and Energy Systems for E-Mobility, 2nd Edition)
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20 pages, 3299 KiB  
Article
Insights into Complex Compounds of Ampicillin: Potentiometric and Spectroscopic Studies
by Justyna Frymark, Michał Zabiszak, Jakub Grajewski, Bartosz Tylkowski and Renata Jastrzab
Int. J. Mol. Sci. 2025, 26(15), 7605; https://doi.org/10.3390/ijms26157605 (registering DOI) - 6 Aug 2025
Abstract
Metal ions, including Mg(II), Ca(II), Sr(II), Co(II), Ni(II), Cu(II), Nd(III), Eu(III), and Tb(III), were investigated in binary systems alongside ampicillin at molar ratios of 1:1 and 1:2. These investigations were carried out in aqueous solutions, and the formation of complexes was verified through [...] Read more.
Metal ions, including Mg(II), Ca(II), Sr(II), Co(II), Ni(II), Cu(II), Nd(III), Eu(III), and Tb(III), were investigated in binary systems alongside ampicillin at molar ratios of 1:1 and 1:2. These investigations were carried out in aqueous solutions, and the formation of complexes was verified through meticulous computational analysis. Detailed stability constants for the formed complexes and equilibrium constants for the involved reactions were meticulously determined. Furthermore, a comprehensive examination of the impact of ligand concentration on the configuration of the central metal atom’s coordination sphere was conducted. This investigation was complemented by spectroscopic measurements, which effectively confirmed the observed changes in the coordination sphere of the metal ions. Full article
(This article belongs to the Section Physical Chemistry and Chemical Physics)
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41 pages, 7308 KiB  
Review
Challenges and Opportunities for Extending Battery Pack Life Using New Algorithms and Techniques for Battery Electric Vehicles
by Pedro S. Gonzalez-Rodriguez, Jorge de J. Lozoya-Santos, Hugo G. Gonzalez-Hernandez, Luis C. Felix-Herran and Juan C. Tudon-Martinez
World Electr. Veh. J. 2025, 16(8), 442; https://doi.org/10.3390/wevj16080442 - 5 Aug 2025
Abstract
The shift from Internal Combustion Engine Vehicles (ICEVs) to Battery Electric Vehicles (BEVs) has accelerated global efforts to decarbonize transportation. However, battery degradation, high costs, and limited lifespan remain critical barriers. This review synthesizes recent innovations to extend Li-ion battery life in BEVs [...] Read more.
The shift from Internal Combustion Engine Vehicles (ICEVs) to Battery Electric Vehicles (BEVs) has accelerated global efforts to decarbonize transportation. However, battery degradation, high costs, and limited lifespan remain critical barriers. This review synthesizes recent innovations to extend Li-ion battery life in BEVs by exploring advances in degradation modeling, adaptive Battery Management Systems (BMSs), electronic component simulations, and real-world usage profiling. The authors have systematically analyzed over 80 recent studies using a PRISMA-guided review protocol. A novel comparative framework highlights gaps in current literature, particularly regarding real-world driving impacts, ripple current effects, and second-life battery applications. This review article critically compares model-driven, data-driven, and hybrid model approaches, emphasizing trade-offs in interpretability, accuracy, and deployment feasibility. Finally, the review links battery life extension to broader sustainability metrics, including circular economy models and predictive maintenance algorithms. This review offers actionable insights for researchers, engineers, and policymakers aiming to design longer-lasting and more sustainable electric mobility systems. Full article
(This article belongs to the Special Issue Electric Vehicle Battery Pack and Electric Motor Sizing Methods)
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23 pages, 918 KiB  
Review
Advances in Graphite Recycling from Spent Lithium-Ion Batteries: Towards Sustainable Resource Utilization
by Maria Joriza Cañete Bondoc, Joel Hao Jorolan, Hyung-Sub Eom, Go-Gi Lee and Richard Diaz Alorro
Minerals 2025, 15(8), 832; https://doi.org/10.3390/min15080832 (registering DOI) - 5 Aug 2025
Abstract
Graphite has been recognized as a critical material by the United States (US), the European Union (EU), and Australia. Owing to its unique structure and properties, it is utilized in many industries and has played a key role in the clean energy sector, [...] Read more.
Graphite has been recognized as a critical material by the United States (US), the European Union (EU), and Australia. Owing to its unique structure and properties, it is utilized in many industries and has played a key role in the clean energy sector, particularly in the lithium-ion battery (LIB) industries. With the projected increase in global graphite demand, driven by the shift to clean energy and the use of EVs, as well as the geographically concentrated production and reserves of natural graphite, interest in graphite recycling has increased, with a specific focus on using spent LIBs and other waste carbon material. Although most established and developing LIB recycling technologies are focused on cathode materials, some have started recycling graphite, with promising results. Based on the different secondary sources and recycling paths reported, hydrometallurgy-based treatment is usually employed, especially for the purification of graphite; greener alternatives are being explored, replacing HF both in lab-scale research and in industry. This offers a viable solution to resource dependency and mitigates the environmental impact associated with graphite production. These developments signal a trend toward sustainable and circular pathways for graphite recycling. Full article
(This article belongs to the Special Issue Graphite Minerals and Graphene, 2nd Edition)
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17 pages, 3151 KiB  
Article
Towards a Consensus for the Analysis and Exchange of TFA as a Counterion in Synthetic Peptides and Its Influence on Membrane Permeation
by Vanessa Erckes, Alessandro Streuli, Laura Chamera Rendueles, Stefanie Dorothea Krämer and Christian Steuer
Pharmaceuticals 2025, 18(8), 1163; https://doi.org/10.3390/ph18081163 - 5 Aug 2025
Abstract
Background: With the increasing shift in drug design away from classical drug targets towards the modulation of protein-protein interactions, synthetic peptides are gaining increasing relevance. The synthesis and purification of peptides via solid-phase peptide synthesis (SPPS) strongly rely on trifluoroacetic acid (TFA) as [...] Read more.
Background: With the increasing shift in drug design away from classical drug targets towards the modulation of protein-protein interactions, synthetic peptides are gaining increasing relevance. The synthesis and purification of peptides via solid-phase peptide synthesis (SPPS) strongly rely on trifluoroacetic acid (TFA) as a cleavage agent and ion-pairing reagent, respectively, resulting in peptides being obtained as TFA salts. Although TFA has excellent properties for peptide production, numerous studies highlight the negative impact of using peptides from TFA salts in biological assays. Methods: Investigated peptides were synthesized via SPPS and the TFA counterion was exchanged for Cl via freeze-drying in different concentrations of HCl. Detection and quantification of residual TFA were carried out via FT-IR, 19F-NMR, and HPLC using an evaporative light-scattering detector (ELSD). A liposomal fluorescence assay was used to test for the influence of the counterion on the peptides’ passive membrane permeability. Results: All TFA detection methods were successfully validated according to ICH guidelines. TFA removal with 10 mM HCl was determined to be the optimal condition. No impact on peptide purity was observed at all HCl concentrations. Influences on permeability coefficients depending on peptide sequence and salt form were found. Conclusions: This study presents a systematic investigation of the removal of TFA counterions from synthetic peptides and their replacement with Cl counterions. Detected counterion contents were used to understand the impact of sequence differences, especially positive charges, on the amount and potential localization of counterions. Our findings emphasize the importance of counterion quantification and specification in assays with synthetic peptides. Full article
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14 pages, 2315 KiB  
Article
A Portable and Thermally Degradable Hydrogel Sensor Based on Eu-Doped Carbon Dots for Visual and Ultrasensitive Detection of Ferric Ion
by Hongyuan Zhang, Qian Zhang, Juan Tang, Huanxin Yang, Xiaona Ji, Jieqiong Wang and Ce Han
Molecules 2025, 30(15), 3280; https://doi.org/10.3390/molecules30153280 (registering DOI) - 5 Aug 2025
Abstract
Degradable fluorescent sensors present a promising portable approach for heavy metal ion detection, aiming to prevent secondary environmental pollution. Additionally, the excessive intake of ferric ions (Fe3+), an essential trace element for human health, poses critical health risks that urgently require [...] Read more.
Degradable fluorescent sensors present a promising portable approach for heavy metal ion detection, aiming to prevent secondary environmental pollution. Additionally, the excessive intake of ferric ions (Fe3+), an essential trace element for human health, poses critical health risks that urgently require effective monitoring. In this study, we developed a thermally degradable fluorescent hydrogel sensor (Eu-CDs@DPPG) based on europium-doped carbon dots (Eu-CDs). The Eu-CDs, synthesized via a hydrothermal method, exhibited selective fluorescence quenching by Fe3+ through the inner filter effect (IFE). Embedding Eu-CDs into the hydrogel significantly enhanced their stability and dispersibility in aqueous environments, effectively resolving issues related to aggregation and matrix interference in traditional sensing methods. The developed sensor demonstrated a broad linear detection range (0–2.5 µM), an extremely low detection limit (1.25 nM), and rapid response (<40 s). Furthermore, a smartphone-assisted LAB color analysis allowed portable, visual quantification of Fe3+ with a practical LOD of 6.588 nM. Importantly, the hydrogel was thermally degradable at 80 °C, thus minimizing environmental impact. The sensor’s practical applicability was validated by accurately detecting Fe3+ in spinach and human urine samples, achieving recoveries of 98.7–108.0% with low relative standard deviations. This work provides an efficient, portable, and sustainable sensing platform that overcomes the limitations inherent in conventional analytical methods. Full article
(This article belongs to the Section Photochemistry)
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14 pages, 8210 KiB  
Article
Effects of Forest Environments in Attenuating D-Galactose-Induced Immunosenescence: Insights from a Murine Model
by Yanling Li and Xiaocong Li
Biology 2025, 14(8), 998; https://doi.org/10.3390/biology14080998 (registering DOI) - 5 Aug 2025
Abstract
With the global aging population on the rise, identifying environmental factors that modulate immunosenescence is critical for health interventions. While urban green spaces are known to confer health benefits, the long-term effects of forest exposure on immunosenescence remain unclear. This study investigated the [...] Read more.
With the global aging population on the rise, identifying environmental factors that modulate immunosenescence is critical for health interventions. While urban green spaces are known to confer health benefits, the long-term effects of forest exposure on immunosenescence remain unclear. This study investigated the differential impacts of urban forest versus urban environments on immunosenescence using a D-galactose-induced murine model. Mice were assigned to urban or forest environments for 8 weeks, with serum cytokines (IL-2, IL-6, TNF-α, IFN-γ), T-cell subsets, and organ indices analyzed. Forest environments exhibited significantly higher humidity and negative air ion concentrations alongside lower noise levels compared to urban settings. Aged forest-exposed mice showed attenuated immunosenescence markers, including significantly lower IL-6 levels (p < 0.01) and improved thymic indices, suggesting urban forest environments may mitigate immune decline. These findings highlight the potential of urban forests in promoting healthy aging, advocating for their integration into urban planning. Further human studies are warranted to translate these findings into public health strategies. Full article
(This article belongs to the Section Immunology)
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12 pages, 617 KiB  
Review
Developments in the Study of Inert Gas Biological Effects and the Underlying Molecular Mechanisms
by Mei-Ning Tong, Xia Li, Jie Cheng and Zheng-Lin Jiang
Int. J. Mol. Sci. 2025, 26(15), 7551; https://doi.org/10.3390/ijms26157551 - 5 Aug 2025
Abstract
It has long been accepted that breathing gases that are physiologically inert include helium (He), neon (Ne), nitrogen (N2), argon (Ar), krypton (Kr), xenon (Xe), and hydrogen (H2). The term “inert gas” has been used to describe them due [...] Read more.
It has long been accepted that breathing gases that are physiologically inert include helium (He), neon (Ne), nitrogen (N2), argon (Ar), krypton (Kr), xenon (Xe), and hydrogen (H2). The term “inert gas” has been used to describe them due to their unusually high chemical stability. However, as investigations have advanced, many have shown that inert gas can have specific biological impacts when exposed to high pressure or atmospheric pressure. Additionally, different inert gases have different effects on intracellular signal transduction, ion channels, and cell membrane receptors, which are linked to their anesthetic and cell protection effects in normal or pathological processes. Through a selective analysis of the representative literature, this study offers a concise overview of the state of research on the biological impacts of inert gas and their molecular mechanisms. Full article
(This article belongs to the Section Molecular Biophysics)
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17 pages, 2219 KiB  
Article
Assessing Lithium-Ion Battery Safety Under Extreme Transport Conditions: A Comparative Study of Measured and Standardised Parameters
by Yihan Pan, Xingliang Liu, Jinzhong Wu, Haocheng Zhou and Lina Zhu
Energies 2025, 18(15), 4144; https://doi.org/10.3390/en18154144 - 5 Aug 2025
Abstract
The safety of lithium-ion batteries during transportation is critically important. However, current standards exhibit limitations, as their environmental testing parameter thresholds fail to fully encompass actual transportation conditions. To enhance both safety and standard applicability, in this study, we focused on four representative [...] Read more.
The safety of lithium-ion batteries during transportation is critically important. However, current standards exhibit limitations, as their environmental testing parameter thresholds fail to fully encompass actual transportation conditions. To enhance both safety and standard applicability, in this study, we focused on four representative environmental conditions: temperature, vibration, shock, and low atmospheric pressure. Field measurements were conducted across road, rail, and air transport modes using a self-developed data acquisition system based on the NearLink communication technology. The measured data were then compared with the threshold values defined in current international and national standards. The results reveal that certain measured values exceeded the upper limits prescribed by existing standards, indicating limitations in their applicability under extreme transport conditions. Based on these findings, we propose revised testing parameters that better reflect actual transport risks, including a temperature cycling range of 72 ± 2 °C (high) and −40 ± 2 °C (low), a shock acceleration limit of 50 gn, adjusted peak frequencies in the vibration PSD profile, and a minimum pressure threshold of 11.6 kPa. These results provide a scientific basis for optimising safety standards and improving the safety of lithium-ion battery transportation. Full article
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38 pages, 4692 KiB  
Review
Progress and Challenges in the Process of Using Solid Waste as a Catalyst for Biodiesel Synthesis
by Zhaolin Dong, Kaili Dong, Haotian Li, Liangyi Zhang and Yitong Wang
Molecules 2025, 30(15), 3243; https://doi.org/10.3390/molecules30153243 - 1 Aug 2025
Viewed by 174
Abstract
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various [...] Read more.
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various methods for preparing biodiesel catalysts from solid waste. These methods not only enhance the utilization rate of waste but also reduce the production costs and environmental impact of biodiesel. Finally, the limitations of waste-based catalysts and future research directions are discussed. Research indicates that solid waste can serve as a catalyst carrier or active material for biodiesel production. Methods such as high-temperature calcination, impregnation, and coprecipitation facilitate structural modifications to the catalyst and the formation of active sites. The doping of metal ions not only alters the catalyst’s acid-base properties but also forms stable metal bonds with functional groups on the carrier, thereby maintaining catalyst stability. The application of microwave-assisted and ultrasound-assisted methods reduces reaction parameters, making biodiesel production more economical and sustainable. Overall, this study provides a scientific basis for the reuse of solid waste and ecological protection, emphasizes the development potential of waste-based catalysts in biodiesel production, and offers unique insights for innovation in this field, thereby accelerating the commercialization of biodiesel. Full article
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29 pages, 4812 KiB  
Article
Geochemical Assessment of Long-Term CO2 Storage from Core- to Field-Scale Models
by Paa Kwesi Ntaako Boison, William Ampomah, Jason D. Simmons, Dung Bui, Najmudeen Sibaweihi, Adewale Amosu and Kwamena Opoku Duartey
Energies 2025, 18(15), 4089; https://doi.org/10.3390/en18154089 - 1 Aug 2025
Viewed by 166
Abstract
Numerical simulations enable us to couple multiphase flow and geochemical processes to evaluate how sequestration impacts brine chemistry and reservoir properties. This study investigates these impacts during CO2 storage at the San Juan Basin CarbonSAFE (SJB) site. The hydrodynamic model was calibrated [...] Read more.
Numerical simulations enable us to couple multiphase flow and geochemical processes to evaluate how sequestration impacts brine chemistry and reservoir properties. This study investigates these impacts during CO2 storage at the San Juan Basin CarbonSAFE (SJB) site. The hydrodynamic model was calibrated through history-matching, utilizing data from saltwater disposal wells to improve predictive accuracy. Core-scale simulations incorporating mineral interactions and equilibrium reactions validated the model against laboratory flow-through experiments. The calibrated geochemical model was subsequently upscaled into a field-scale 3D model of the SJB site to predict how mineral precipitation and dissolution affect reservoir properties. The results indicate that the majority of the injected CO2 is trapped structurally, followed by residual trapping and dissolution trapping; mineral trapping was found to be negligible in this study. Although quartz and calcite precipitation occurred, the dissolution of feldspars, phyllosilicates, and clay minerals counteracted these effects, resulting in a minimal reduction in porosity—less than 0.1%. The concentration of the various ions in the brine is directly influenced by dissolution/precipitation trends. This study provides valuable insights into CO2 sequestration’s effects on reservoir fluid dynamics, mineralogy, and rock properties in the San Juan Basin. It highlights the importance of reservoir simulation in assessing long-term CO2 storage effectiveness, particularly focusing on geochemical interactions. Full article
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30 pages, 2537 KiB  
Review
The State of Health Estimation of Lithium-Ion Batteries: A Review of Health Indicators, Estimation Methods, Development Trends and Challenges
by Kang Tang, Bingbing Luo, Dian Chen, Chengshuo Wang, Long Chen, Feiliang Li, Yuan Cao and Chunsheng Wang
World Electr. Veh. J. 2025, 16(8), 429; https://doi.org/10.3390/wevj16080429 - 1 Aug 2025
Viewed by 248
Abstract
The estimation of the state of health (SOH) of lithium-ion batteries is a critical technology for enhancing battery lifespan and safety. When estimating SOH, it is essential to select representative features, commonly referred to as health indicators (HIs). Most existing studies primarily focus [...] Read more.
The estimation of the state of health (SOH) of lithium-ion batteries is a critical technology for enhancing battery lifespan and safety. When estimating SOH, it is essential to select representative features, commonly referred to as health indicators (HIs). Most existing studies primarily focus on HIs related to capacity degradation and internal resistance increase. However, due to the complexity of lithium-ion battery degradation mechanisms, the relationships between these mechanisms and health indicators remain insufficiently explored. This paper provides a comprehensive review of core methodologies for SOH estimation, with a particular emphasis on the classification and extraction of health indicators, direct measurement techniques, model-based and data-driven SOH estimation approaches, and emerging trends in battery management system applications. The findings indicate that capacity, internal resistance, and temperature-related indicators significantly impact SOH estimation accuracy, while machine learning models demonstrate advantages in multi-source data fusion. Future research should further explore composite health indicators and aging mechanisms of novel battery materials, and improve the interpretability of predictive models. This study offers theoretical support for the intelligent management and lifespan optimization of lithium-ion batteries. Full article
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7 pages, 1017 KiB  
Communication
Observing the Ionization of Metastable States of Sn14+ in an Electron Beam Ion Trap
by Qi Guo, Zhaoying Chen, Fangshi Jia, Wenhao Xia, Xiaobin Ding, Jun Xiao, Yaming Zou and Ke Yao
Atoms 2025, 13(8), 71; https://doi.org/10.3390/atoms13080071 - 1 Aug 2025
Viewed by 124
Abstract
This study investigates the ionization balance of Sn ions in an electron beam ion trap (EBIT). Highly charged Sn ions are produced via collisions with a quasi-monochromatic electron beam, and the charge state distribution is analyzed using a Wien filter. Significant Sn15+ [...] Read more.
This study investigates the ionization balance of Sn ions in an electron beam ion trap (EBIT). Highly charged Sn ions are produced via collisions with a quasi-monochromatic electron beam, and the charge state distribution is analyzed using a Wien filter. Significant Sn15+ production occurs at electron energies below the ionization potential of Sn14+ (379 eV). Calculations attribute this to electron-impact ionization from metastable Sn14+ states. Full article
(This article belongs to the Special Issue 21st International Conference on the Physics of Highly Charged Ions)
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19 pages, 7130 KiB  
Article
Modification Effects and Mechanism of Cement Paste Wrapping on Sulfate-Containing Recycled Aggregate
by Xiancui Yan, Wen Chen, Zimo He, Hui Liu, Shengbang Xu, Shulin Lu, Minqi Hua and Xinjie Wang
Materials 2025, 18(15), 3617; https://doi.org/10.3390/ma18153617 - 31 Jul 2025
Viewed by 181
Abstract
The utilization of recycled concrete aggregate presents an effective solution for construction waste mitigation. However, concrete service in sulfate environments leads to sulfate ion retention in recycled aggregates, substantially impairing their quality and requiring modification approaches. A critical question remains whether traditional recycled [...] Read more.
The utilization of recycled concrete aggregate presents an effective solution for construction waste mitigation. However, concrete service in sulfate environments leads to sulfate ion retention in recycled aggregates, substantially impairing their quality and requiring modification approaches. A critical question remains whether traditional recycled aggregate modification techniques can effectively enhance the performance of these sulfate-containing recycled aggregates (SRA). Cement paste wrapping in various proportions was used in this investigation to enhance SRA. The performance of both SRA and modified aggregates was systematically assessed through measurements of apparent density, water absorption, crushing value, and microhardness. Microstructural analysis of the cement wrapping modification mechanism was conducted by scanning electron microscopy coupled with mercury intrusion porosimetry. Results revealed that internal sulfate addition decreased the crushing value and increased the water absorption of recycled aggregates, primarily due to micro-cracks formed by expansion. Additionally, the pores were occupied by erosion products, leading to a slight increase in the apparent density of aggregates. The performance of SRA was effectively enhanced by cement paste wrapping at a 0.6 water–binder ratio, whereas it was negatively impacted by a ratio of 1.0. The modifying effect became even more effective when 15% fly ash was added to the wrapping paste. Scanning electron microscopy observations revealed that the interface of SRA was predominantly composed of gypsum crystals. Cement paste wrapping greatly enhanced the original interface structure, despite a new dense interface formed in the modified aggregates. Full article
(This article belongs to the Special Issue Research on Alkali-Activated Materials (Second Edition))
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18 pages, 2393 KiB  
Article
Phosphate Transport Through Homogeneous and Heterogeneous Anion-Exchange Membranes: A Chronopotentiometric Study for Electrodialytic Applications
by Kayo Santana-Barros, Manuel César Martí-Calatayud, Svetlozar Velizarov and Valentín Pérez-Herranz
Membranes 2025, 15(8), 230; https://doi.org/10.3390/membranes15080230 - 31 Jul 2025
Viewed by 215
Abstract
This study investigates the behavior of phosphate ion transport through two structurally distinct anion-exchange membranes—AMV (homogeneous) and HC-A (heterogeneous)—in an electrodialysis system under both static and stirred conditions at varying pH levels. Chronopotentiometric and current–voltage analyses were used to investigate the influence of [...] Read more.
This study investigates the behavior of phosphate ion transport through two structurally distinct anion-exchange membranes—AMV (homogeneous) and HC-A (heterogeneous)—in an electrodialysis system under both static and stirred conditions at varying pH levels. Chronopotentiometric and current–voltage analyses were used to investigate the influence of pH and hydrodynamics on ion transport. Under underlimiting (ohmic) conditions, the AMV membrane exhibited simultaneous transport of H2PO4 and HPO42− ions at neutral and mildly alkaline pH, while such behavior was not verified at acidic pH and in all cases for the HC-A membrane. Under overlimiting current conditions, AMV favored electroconvection at low pH and exhibited significant water dissociation at high pH, leading to local pH shifts and chemical equilibrium displacement at the membrane–solution interface. In contrast, the HC-A membrane operated predominantly under strong electroconvective regimes, regardless of the pH value, without evidence of water dissociation or equilibrium change phenomena. Stirring significantly impacted the electrochemical responses: it altered the chronopotentiogram profiles through the emergence of intense oscillations in membrane potential drop at overlimiting currents and modified the current–voltage behavior by increasing the limiting current density, reducing electrical resistance, and compressing the plateau region that separates ohmic and overlimiting regimes. Additionally, both membranes showed signs of NH3 formation at the anodic-side interface under pH 7–8, associated with increased electrical resistance. These findings reveal distinct ionic transport characteristics and hydrodynamic sensitivities of the membranes, thus providing valuable insights for optimizing phosphate recovery via electrodialysis. Full article
(This article belongs to the Section Membrane Applications for Water Treatment)
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