This study evaluates the structural characteristics and electrochemical performance of commercially available carbon paper as a binder-free, free-standing anode for both lithium-ion batteries (LIBs) and sodium-ion batteries (NIBs). The carbon paper consists of a three-dimensionally interconnected carbon fiber network that provides excellent electrical conductivity and mechanical stability, while its porous framework facilitates electrolyte penetration and ion diffusion. Structural analysis revealed the coexistence of crystalline graphitic domains and amorphous carbon regions with a low specific surface area, which helps suppress side reactions with the electrolyte while maintaining stable ion storage behavior. Electrochemical tests showed that, in LIBs, the graphitic domains contribute to lithium intercalation and enable excellent rate capability even at a high rate of 5 C. In NIBs, the amorphous carbon regions dominate the sodium storage behavior, exhibiting a typical sloping voltage profile associated with nanopore-based sodium storage. These results suggest that carbon paper possesses unique structural and electrochemical characteristics that make it a promising free-standing anode material for both LIB and NIB systems.
A gas-liquid carbonation process assisted by a rotor-stator high-shear mixer was proposed for efficient production of lithium carbonate (Li2CO3). An aqueous LiCl solution, NaOH, and CO2 were used as reactants, and the reaction behavior was compared with that of a conventional batch reactor equipped with an axial impeller. The strong shear field in the rotor-stator system generated fine bubbles and increased the gas-liquid interfacial area, resulting in markedly faster carbonation. Under the optimized conditions (2000 rpm and CO2 2.0 L/min), the reaction was completed within 20 min, producing Li2CO3 with > 99.5% purity and a uniform particle size distribution with a mean size of 12.4 & micro;m, satisfying battery-grade requirements. The proposed process provides a practical route for simultaneous CO2 utilization (CCU) and rapid recovery of high-value lithium resources.
The use of wood poses a significant threat to human safety and property preservation in the event of a fire. In this study, the fire risk of wood was evaluated using Chung's equation-IV and Chung's equation-XII. The test subjects were selected as building materials such as larch, Russian ash, cherry, and camphor and performed using the cone calorimeter according to ISO 5660-1.The test subjects were selected as building materials such as larch, Russian ash, cherry, and camphor and the experiment was conducted using a cone calorimeter according to ISO 5660-1. The evaluation results by fire risk index-IV (FRI-IV) and fire risk index-XII (FRI-XII) were compared. According to the FRI-IV, the larch (0.01) was described as the wood with the lowest fire risk, and polymethylmethacrylate (PMMA) (1.00) was evaluated as the wood with the highest fire risk. However, according to the fire risk index-XII, the fire risk was evaluated as the lowest for larch (0.07) as grade A and the highest for Russian ash (4.10) as grade F. Therefore, the fire risk evaluation by Chung's equation-XII is explained as a useful method to comprehensively evaluate the prediction of the fire risk of combustion targets.
With the growing demand for large-scale energy storage driven by the expansion of renewable energy, Na-ion batteries (NIBs) have emerged as promising next-generation electrochemical storage systems. As lithium resources become increasingly scarce and costly, the importance of NIBs, which offer both low cost and high stability, has gained significant attention. Abundant Na resources provide notable economic and environmental advantages, particularly for large-scale energy storage applications. In this context, research efforts have increasingly focused on a wide range of carbon-based anode materials-such as graphite, graphene, soft carbon, and hard carbon-to elucidate how their structural and chemical properties govern sodium storage behavior and electrochemical performance. This review provides a comprehensive analysis of the characteristics of carbon-based anode materials and the strategies for enhancing their performance and further outlines key design directions and future research perspectives for developing high-performance Na-ion battery anodes.
This study developed a water-removable, eco-friendly adhesive using waste pumpkin seed protein and tannic acid as primary components, with citric acid serving as an auxiliary additive. The polyphenolic structure of tannic acid forms various intermolecular interactions, including hydrogen bonding with proteins. Under heat treatment conditions, it induces network formation together with citric acid, thereby enhancing the water resistance and mechanical strength of the adhesive. The resulting adhesive maintained stability under humid conditions but readily detached in room-temperature water, with the degree of separation adjustable according to adhesive concentration. Notably, the formulation containing 10 wt% tannic acid exhibited optimal cross-linking, achieving a balance between water resistance and adhesion. Furthermore, the use of waste-derived materials prevents water pollution, confirming environmental sustainability, and suggests potential applications in recycling processes, such as removing labels from glass bottles.
This study optimized the preparation conditions of oil-in-water (O/W) emulsions containing medium chain triglyceride (MCT) oil and sugar esters to enhance their stability, utilizing central composite design model-response surface methodology (CCD-RSM). The hydrophile-lipophile balance (HLB) value and surfactant concentration were selected as independent variables, while the emulsion stability index (ESI), mean droplet size (MDS), and droplet size distribution index (SPAN) were analyzed as response variables. The optimization results indicated that the optimal conditions were an HLB value of 6.7 and a surfactant concentration of 3.6 wt%. Under these conditions, the predicted response values were determined to be an ESI of 84.7%, an MDS of 4119.1 nm, and a SPAN of 0.77. The overall desirability was found to be 0.999, verifying the significance and reliability of the CCD-RSM model applied in this study.
In this study, the whitening activity, antioxidant activity, and mean droplet size of an emulsion prepared using Hippophae rhamnoides L. fruit extract and polyoxyethylene oleyl ether (POE) emulsifiers were optimized. The amounts of sea buckthorn fruit extract and emulsifier were set as independent variables, and the resulting optimal emulsification conditions were determined to be 3.5 wt% and 6.2 wt%, respectively. The predicted responses were calculated as 35.9% for whitening activity, 37.7% for antioxidant activity, and 4.6 & micro;m for mean droplet size. The actual experiments yielded a mean error rate of +/- 1.1%, confirming the applicability of emulsions containing sea buckthorn fruit extract as potential whitening functional materials.
Non-isocyanate polyurethanes were synthesized by reacting castor oil-based cyclic carbonates with amines of varying chain lengths, and the effects of amine carbon chain length on the resulting material properties were investigated. The chemical structures of the resulting NIPU films were characterized using FT-IR and H-1-NMR spectroscopy, confirming the formation of urethane, urea, and amide functional groups. As the carbon chain length of the amine decreased, enhanced accessibility to the polymer backbone facilitated additional reactions leading to increased formation of urea and amide linkages. The synthesized NIPU film exhibited a tensile strength of up to 0.38 MPa and an initial decomposition temperature of 372 degrees C, as determined by a universal testing machine and thermogravimetric analysis (TGA). The improvement in hydrophilicity was confirmed through contact angle measurements.
With the emergence of novel narcotics and chemical warfare agents, structural elucidation of unknown chemical substances is essential for chemical incident response. Field detection equipment provides rapid alerts but faces false positive issues, necessitating robust verification. This study examines an integrated strategy combining infrared (IR), Raman, and nuclear magtional group information, Raman reveals molecular backbone vibrations, and NMR offers bonding relationships. Since spectral variations occur depending on experimental conditions and computational settings , applying scaling factors can reduce average errors. This study presents a systematic procedure for evaluating relative suitability among structural candidates by connecting IR-Raman-NMR results and utilizing DFT predictions as comparative references. Integrating multi-spectroscopic data and cross-validating with computational predictions effectively reduces errors caused by relying solely on individual methods. The proposed procedure will serve as a practical reference standard in the structural verification of unknown compounds.
In this study, chitosan (CS)-based edible films were prepared using a casting method combined with a UV curing process, and their physical properties, thermal stability, optical properties, antibacterial activity, biodegradation behavior, and coating performance were evaluated. Glycerol (GL) and mannitol (MAN) were used as plasticizers to investigate the effects of plasticizer type on film properties. Response surface methodology (RSM) was applied to determine the optimal processing condition, which was identified as UV curing at 25 degrees C for 30 min. Thermal analysis indicated that UV curing affected the thermal stability of the films. Optical analysis confirmed that the films exhibited effective UV-blocking properties. Soil burial tests showed that the prepared CS-based edible films exhibited 40.0 similar to 80.0% biodegradation, and UV curing played a role in controlling the degradation rate. In addition, apple coating experiments demonstrated that the films delayed surface browning and quality deterioration. These results suggest that the structural and functional properties of CS-based edible films can be simultaneously tuned by UV crosslinking and plasticizer composition, indicating their potential application as eco-friendly functional food packaging materials.
This study proposes a new activation method for nitrogen-doped activated carbon derived from kenaf biomass for CO2 adsorption. To overcome the limitations of the existing potassium carbonate (K2CO3) activator, diammonium phosphate ((NH4)(2)HPO4) was used as an auxiliary activator. At this time, the pore and surface chemical changes in activated carbon as a function of ammonium phosphate content, and the effect of its surface chemical characteristics on CO2 adsorption performance, were evaluated. Diammonium phosphate successfully introduced pyridine-N-and pyrrolic-N-based nitrogen functional groups onto the activated carbon surface in all samples and promoted the formation of micropores, thereby increasing the specific surface area. KENAF_NAC0.50, which possesses a specific surface area of 2431.8 m2 g(-1) and an ultra-micropore volume of 0.151 cm3 g(-1), demonstrated approximately 25% greater CO2 adsorption performance at 298 K and 1 bar compared to KENAF_AC. KENAF_NAC0.50 showed the highest CO2 adsorption capacity of 6.58, 4.00, and 3.08 mmol g(-1 )at 273, 298, and 313 K, respectively, and the highest CO2 /N-2 selectivity at room temperature under 1 bar conditions, demonstrating the best performance among the samples.
Conventional low-temperature seawater electrolysis is hindered by severe electrode corrosion, performance losses, and complex pretreatment requirements arising from salts and impurities. This review highlights solid oxide electrolysis cells (SOECs) as a promising alternative for sustainable hydrogen production. Operating at elevated temperatures (700-1000 degrees C) and readily integrated with renewable heat or electricity sources, SOECs enable the conversion of seawater supplied as steam, thereby eliminating the need for separate desalination steps. Despite these advantages, challenges remain, particularly regarding electrode stability and catalyst degradation under harsh high-temperature and high-salinity conditions. This paper examines recent advances in electrode and catalyst design and outlines material strategies aimed at enhancing durability and performance in seawater-driven SOEC systems.
This study investigates the effects of post-treatment with chemical activating agents (KOH, NaOH, and ZnCl2) on the CO2 and N2 adsorption properties of commercial pellet-type activated carbons (ACs). The structural and surface chemical characteristics of the ACs were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and N2 adsorption isotherms. The adsorption isotherms of CO2 and N2 were measured using a volumetric adsorption apparatus at three temperatures (288, 298, and 308 K) up to 110 kPa. The results revealed that the adsorption capacities of both CO2 and N2 exhibited a significantly stronger correlation with the ultra-micropore volume than with the specific surface area, total pore volume, or N/C ratio. Adsorption isotherms were fitted using temperature-dependent Langmuir (T-Lang), temperature-dependent Sips (T-Sips), and adsorption energy distribution (AED)-based Langmuir model (T-HL), among which the T-HL model provided the best fitting performance. The AED function was particularly effective in explaining the differences in adsorption energy characteristics between CO2 and N2. Furthermore, both the AED and the isosteric heat of adsorption showed strong correlations with the ultra-micropore volume. The adsorption selectivities obtained from ideal adsorbed solution theory (IAST), as well as the pure-component selectivities, were strongly associated with the ultra-micropore volume and the CO2-N2 adsorption amount difference. These findings demonstrate that the ultra-microporous structure is the governing factor for CO2/N2 adsorption and separation performance, and confirm that AED-based adsorption models provide a robust and physically meaningful framework for interpreting the adsorption behavior of activated carbons.
In this study, a conductive materials-coated SiOx/graphite composite anode was fabricated using an improved coating method to mitigate the volume expansion of silicon oxide (SiOx), a high-capacity anode active material for lithium-ion batteries, and to enhance its cycling stability. Conventional processes primarily rely on carbon coating followed by carbonization; however, these approaches suffer from limitations in terms of time consumption and cost. To address these issues, the present study introduces a solution-based coating process employing a commercially available conductive coating agent, which enables the elimination of prolonged high-temperature heat-treatment steps and thereby significantly reduces both processing time and manufacturing cost. In addition, compared to the uncoated SiOx/graphite anode, the coated composite anode exhibits higher discharge capacity at high current rates and improved cycle life. When compared with samples prepared via conventional coating processes, the proposed method demonstrates nearly comparable discharge capacity under high-rate xconditions.
Natural materials, including wood, are becoming increasingly important for fire safety along with eco-friendly living. The fire risks of combustible materials were comprehensively reviewed using Chung's equation-XII and the newly proposed Chung's equation-XV. As a case study, the fire characteristics of five wood specimens were evaluated using a cone calorimeter according to the ISO 5660-1 standard. The external heat flux was set to 50 kW/m(2). The relative rankings based on the fire risk index-XII (FRI-XII) were as follows: zelkova (0): ranking 6 < oak (0.02): ranking 5 < pine rigida (0.09): ranking 4 < chestnut (0.19): ranking 3 < polymethylmethacrylate (PMMA) (1): ranking 2 < lauan (4.69): ranking 1. The relative rankings based on the fire risk index-XV (FRI-XV) were as follows: zelkova (0.00): ranking 3 approximate to oak (0.00): ranking 3 approximate to pine rigida (0.00): ranking 3 approximate to chestnut (0.00): ranking 3 < lauan (0.03): ranking 2 < PMMA (1): ranking 1. However, the results based on the fire risk index-XV (FRI-XV) did not provide discrimination between test specimens. Therefore, it was found that there is a need to comprehensively evaluate the fire risk, including the ratio of mean carbon monoxide production rate (COPmean, g/s) to mean carbon dioxide production rate (CO2Pmean, g/s), as in the evaluation of FRI-XII.
The nanozyme activity of a platinum-incorporated multi-walled carbon nanotube and graphene oxide nanoribbon composite (Pt/MWCNT-GONR) was systematically investigated using colorimetric and chronoamperometric analyses. The nanozyme composite was prepared by inducing nanoribbon formation to enhance MWCNT oxidation via microwave treatment, followed by the loading of platinum particles using a self-reduction approach. The formation of nanoribbons and the attachment of platinum particles on the composite were confirmed by transmission electron microscopy and X-ray diffraction analysis. The peroxidase (POD)-like activity of the synthesized Pt/MWCNT-GONR nanozyme was first evaluated using a colorimetric assay by reacting it with 2 mM 3,3'5,5'-tetramethylbenzidine (TMB) in the presence of 2 mM hydrogen peroxide (H2O2 ). By analyzing the change in absorbance as a function of time in the initial reaction region, the specific activity of the Pt/MWCNT-GONR nanozyme was calculated to be 1.6768 U & centerdot;mg-1. In addition, after reacting the Pt/MWCNT-GONR nanozyme under the same concentrations of H2O2 and TMB for 3 min, a potential of-0.1 V (vs. Ag/AgCl) corresponding to the reduction potential of TMB was applied, and the POD-like activity was measured by chronoamperometry. In particular, when the concentrations of TMB and H2O2 were held constant, increasing the amount of nanozyme enhanced the TMB oxidation reaction, leading to a corresponding increase in the steady-state current change (Delta I). These results confirm the successful synthesis of a POD-like nanozyme.
Synthetic esters, typically produced through the esterification of fatty acids and alcohols, have gained considerable attention as next-generation insulating oils due to their excellent electrical insulation, oxidative and fire stability, and biodegradability. In this study, fly ash obtained from two thermal power plants, Cebu fly ash (CFA) and Taean fly ash (TFA), was employed as a catalyst to enhance esterification reactivity. Fly ash contains not only Si and Al but also various metals, making it a promising catalytic material. To investigate the physicochemical properties of fly ash, X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption were performed. For the esterification reaction, decanoic acid (capric acid) and 2-ethylhexanoic acid served as fatty acid components, while pentaerythritol acted as the alcohol. Catalytic performance evaluation demonstrated that CFA showed slightly higher reactivity than TFA at 210 degrees C. A high conversion of 95.4% was achieved after 9 h of reaction at 230 degrees C.
Glycolysis of poly(ethylene terephthalate) (PET) is an attractive chemical recycling route because it regenerates the monomer bis(2-hydroxyethyl) terephthalate (BHET) with high purity. Zinc acetate is a benchmark catalyst for this reaction, and studies have suggested that tertiary amines can act as cocatalysts to improve the reaction rate and BHET yield. In this study, we systematically evaluated six tertiary amines, namely 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene methylguanidine (TMG), in zinc-acetate-catalyzed glycolysis of post-consumer PET cups. The reaction progress was quantified by time-resolved 1H NMR and by isolation and gravimetric analysis of BHET. Among the examined amines, DBN gave the highest PET conversion (97%) and BHET yield (83%) at 180 degrees C after 120 min, while DBU showed comparable performance (95% conversion, 80% yield) with a notably faster BHET buildup during the early stage. TBD showed only a modest rate/yield enhancement, whereas TEA, DMAP, and TMG suppressed zinc acetate activity. These trends are not simply correlated with basicity, and the results are best rationalized by considering DBU/DBN as a strong nonnucleophilic base that enhances ethylene glycol nucleophilicity while avoiding deleterious coordination to Zn2+. These insights can be used to determine whether tertiary amines are beneficial or counterproductive cocatalysts in PET glycolysis.
In this study, the effects of a new naturally derived cosmetic preservative on the dispersion stability of cosmetic formulations are studied. The new preservative is a bispropanediol derivative, which has a hydrophobic hydrocarbon part derived from fats or oils and a hydrophilic glycol structure. The carbon length of the hydrocarbon part is 14, and the hydrophilic-lipophilic balance (HLB) of the new preservative is approximately 9.1. Both essence and lotion formulations are prepared containing the new preservative, and major parameters such as composition and the new emulsifier are optimized to alleviate phase separation during preparation of the formulations. Dispersion stability of the formulations is analyzed using the light transmittance method. Consequently, it is found that the effect of a new preservative addition on the essence formulation is insignificant. However, for lotion formulation, the effect of variation in emulsifier composition originating from new emulsifier addition is more dominant than other parameters. This study provides important information for future research activities regarding natural cosmetic preservative.
Lithium-sulfur (Li-S) batteries are promising alternatives to conventional energy storage devices owing to their superior theoretical capacity, low cost, and environmentally sustainable sulfur source. However, the practical application is limited by polysulfide dissolution, the poor conductivity of sulfur, and large volume variations during cycling, leading to rapid capacity fading and low efficiency. To address these issues, we prepared Ni-BTC/multi-walled carbon nanotubes (MWCNTs) composites as sulfur host materials. MWCNTs were acid-treated to introduce oxygen-containing functional groups, improving their dispersion and interfacial compatibility with Ni-BTC during solvothermal synthesis. Structural characterization confirmed uniform incorporation of MWCNTs within the Ni-BTC framework. Among the prepared composites, the Ni-BTC/MWCNT-30% sample demonstrated the most balanced performance. This electrode exhibited a narrower redox separation potential (Delta E: 0.450 V) in cyclic voltammetry, extended discharge plateaus in galvanostatic profiles, and favorable rate capability with a reversible capacity of similar to 895 mAh g(-1) at 0.1 C. Long-term cycling further revealed that the composite consistently delivered higher discharge capacities than pristine Ni-BTC, attributed to the conductive carbon framework, which promoted charge transfer and suppressed polysulfide shuttle. These findings highlight that integrating Ni-BTC with functionalized MWCNTs overcomes conductivity limitations of MOFs and provides a viable approach to achieving enhanced performance sulfur hosts in Li-S batteries.
