Search Results (1,585)

To enhance the mechanical properties and waterproof performance of polymer–cement (JS) waterproof coatings, cellulose nanofibrils (CNFs) were surface-modified using vinyltriethoxysilane (VTES). The modified cellulose nanofibrils (m-CNFs) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) analysis, and energy-dispersive X-ray spectroscopy (EDS). JS waterproof coatings incorporating m-CNFs were subsequently prepared. The performance and mechanism were systematically evaluated using the tensile strength, bonding strength, water absorption, contact angle, permeability test, durability test, scanning electron microscopy, Brunauer–Emmett–Teller (BET) and atomic force microscopy (AFM). The results indicated that the coating exhibited optimal performance when 1 wt% m-CNFs were incorporated. Under this condition, the tensile strength and bonding strength increased by 33.8% and 9.8%, respectively, while the 7-day water absorption decreased by 72.9%. The contact angle reached 97.1°, and the durability of the coating was also improved. Moreover, the amphiphilic nature introduced by silane modification effectively improved the interfacial adhesion between the organic and inorganic phases within the coating. In addition, due to their water absorption capacity, m-CNFs fill the micropores of the coating during the curing process and produce an internal curing effect, thereby reducing the porosity of the material. As a result of these synergistic effects, the mechanical strength and hydrophobicity of the JS waterproof coating are significantly enhanced. This study expands the application of CNFs, a sustainable nanomaterial, in building waterproofing materials. Full article

This research enhances the literature on bank capital structure by combining financial intermediation theory with technological innovation to analyse the impact of FinTech adoption and liquidity management on leverage choices in South African banks. Utilising panel data spanning 2015 to 2024 and applying the Generalised Method of Moments (GMM) to tackle endogeneity and dynamic persistence, the research presents new findings from an overlooked emerging market setting. The results show a diverse effect of technology on leverage. Conventional banking systems, represented by automated teller machines (ATMs), show a positive relationship with the total debt ratio (TDR), suggesting a capital-intensive nature of tangible assets. Conversely, digital technologies such as mobile banking and a composite FinTech Index display a notable negative correlation with leverage, indicating that digital transformation improves efficiency, strengthens internal funding capacity, and reduces dependence on external debt. Moreover, increased liquidity levels are negatively correlated with leverage, suggesting that well-capitalised banks with robust liquidity rely less on debt funding. By examining FinTech and liquidity dynamics, the research contributes to both theory and practice, emphasising digital innovation as an alternative to external funding and stressing the importance of sound liquidity management amid evolving regulatory environments such as Basel III. Full article

Electronics evolution drives SMMs as a frontier, overcoming conventional magnetic material limits via molecular spin coupling. Two relevant Co(II) mononuclear complexes, [Co(MOP)₄(N₃)₂] (1) and [Co(MSP)₄(N₃)₂] (2) (MOP = 4-methoxypridine and MSP = 4-methylthiopyridine) were synthesized through changing the substituents of ligands. The Co(II) ions in the two complexes show octahedron coordination geometries. The replacement of the O to S in the equatorial plane leads to different Jahn–Teller effect because of the shorter Co(II)-N in the equatorial plane, resulting in the significantly different slow relaxation process confirmed by ab initio calculation. The results confirm the Co(II) ion is sensitive to ligand field. Full article

Traditional nano-titanium dioxide films have strong photocatalytic performance; however, their hydrophilic surfaces make it easier for pollutants or by-products resulting from the reaction processes to deposit on the membrane surface and occupy their active sites, which reduces the coating degradation efficiency and shortens their service life. In the current study, nano-TiO₂ was mixed with SiO₂ for hydrophobic film coating by the sol–gel method. The surface morphology of the membrane was observed by scanning electron microscopy (SEM), the composition of the coating was analyzed by X-ray diffraction (XRD), and its stable hydrophobicity was verified by contact angle testing (θ_w = 117°). The specific surface area Brunauer–Emmett–Teller (BET) revealed between 0.0561 (for 3 layers) and 0.0868 m²/g after 9 layers of coating. Through establishing a simplified photocatalytic reactor under UV, the new coating’s abilities in the degradation of methylene blue, its anti-fouling, and durability were examined. Results revealed that when the common TiO₂ films were combined with hydrophobic films, nearly 100% of methylene blue was degraded, and the degradation capacity remained stable after three rounds of tests. Moreover, it was observed that only a small amount of methylene blue adhered to the new film surface comparatively. Outcomes confirmed that the SiO₂-mixed TiO₂ thin films exhibited enhanced hydrophobicity. When integrated with ordinary TiO₂ coatings, the composite structure demonstrated superior photocatalytic efficiency and stability in the degradation of aqueous pollutants compared to pure TiO₂ coatings. Full article

Red Amaranth (RA) Azo dye is a persistent pollutant in wastewater and stands as a toxicological risk, which has led to the development of effective methods for its removal and photocatalytic degradation. Therefore, CeO₂ nanoparticles were synthesized by a controlled precipitation method, and Ultraviolet-Visible (UV–Vis) analysis and Tauc plots yielded a band gap of ~3.24 eV. The CeO₂ nanoparticles showed the fluorite cubic phase, and nearly spherical particles with an average size of ~10 nm. Nitrogen physisorption revealed a type IV isotherm with a Brunauer–Emmett–Teller (BET) surface area of 85.27 m²·g⁻¹ and a total pore volume of 0.27 cm³·g⁻¹, indicating a mesoporous structure and high surface accessibility. The chemical behavior showed Ce and O, consistent with phase purity. Photocatalytic performance was evaluated in 20 ppm aqueous solution of RA under 365 nm UV irradiation (LED 100 W), with a temperature of ~20 °C and a 15 min dark adsorption step. Concentration decay was followed at λ_max = 520 nm by Lambert–Beer. The degradation efficiency η and pseudo-first-order kinetic were obtained from ln(C₀/C_t) vs. time. In addition, chemical oxygen demand (COD) tests were performed on RA solution before and after photodegradation, showing a COD reduction of ~85% (from 19.8 to 3 mg O₂·L⁻¹), which corroborates mineralization beyond chromophore bleaching. Under [C₀ = 20 mg·L⁻¹] and [m_cat = 1.0 g·L⁻¹], CeO₂ achieved [RA = 90% at 180 min, k = 0.0125 min⁻¹]. These results demonstrate that CeO₂ is an effective photocatalyst for RA degradation under UV-A irradiation, integrating adsorption, kinetic behavior, and mineralization performance into a coherent structure–property relationship. Full article

Graphene incorporation into polymer fibers offers a strategy to tune nanoscale morphology while preserving mechanical conformity for flexible composite applications. Graphene-based dopants can enable modulation of polymer fiber structure; however, the relationship between graphene incorporation, fiber morphology, and mechanical flexibility must be evaluated. This study investigates the integration of graphene oxide (GO) and reduced graphene oxide (RGO) into fibrous materials to tailor the structural and surface characteristics by fabricating GO- and RGO-enhanced poly(vinylidene fluoride) (PVDF) fibers via a wet-spinning process and examining the tunability of their morphology and its influence on mechanical properties. The effect of graphene doping and reduction state on fiber architecture is explored using scanning electron microscopy (SEM), atomic force microscopy (AFM), and Brunauer–Emmett–Teller (BET) surface area analysis. Fourier transform infrared (FTIR) and Raman spectroscopy analyses confirmed the incorporation and reduction of graphene derivatives within the PVDF matrix while revealing corresponding changes in chemical functionality and the piezoelectric phase of PVDF. Mechanical flexibility is assessed through tensile testing, revealing increased stiffness with graphene addition, although maintaining sufficient structural integrity for wearable applications. These results collectively demonstrate that graphene doping provides a facile route to engineer composite fibers, enabling a balance between morphological complexity and mechanical compliancy, while establishing graphene-enhanced fibers as promising materials for flexible sensing systems and wearable smart textiles. Full article

The widespread use of plastics has inevitably led to the accumulation of persistent plastic debris in aquatic systems, where gradual fragmentation generates microplastics (MPs) that threaten ecological and biological health. Their small size, chemical stability, and resistance to degradation make effective removal particularly challenging. In this work, a composite adsorbent was fabricated through the in situ solvothermal growth of Materials of Institute Lavoisier 100 (Iron) (MIL-100(Fe)) onto coconut shell-derived activated carbon (CSAC), yielding a monolithic material denoted as CSAC@MIL-100(Fe). The integration of porous C with a metal–organic framework created a hierarchically structured adsorbent rich in accessible binding sites. The composite achieved a maximum polystyrene (PS) removal efficiency of 97.4% and maintained 91.44% efficiency after seven regeneration cycles. Stable adsorption performance was observed across a broad pH range. Structural and chemical analyses (scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS)) combined with adsorption modeling revealed heterogeneous multilayer adsorption behavior consistent with the Freundlich isotherm and pseudo-second-order kinetics. π–π interactions, electrostatic attraction, and coordination effects jointly governed PS capture. The Langmuir maximum adsorption capacity reached 746.27 mg/g. These findings demonstrate a practical and recyclable strategy for efficient MP remediation in aquatic environments. Full article

Biochars are currently proposed as soil amendments or sorbent materials. There is an extensive scientific literature that deals with biochars originating from different raw materials. However, a holistic physicochemical characterization with simple analytical techniques is needed to provide insights on the characteristics of the biochars produced from malt spent rootlets (MSRs) and how they vary using different pyrolysis temperatures. This way, their properties can be fully understood, and they can be used for commercial purposes more effectively. Initially, the texture of the biochars were visualized by SEM and was quantified by the adsorption/desorption of nitrogen and the Brunauer, Emmett, and Teller (BET) equation. Additionally, the moisture content, the ash content and the pH of each sample were measured. Furthermore, the electrical conductivity of each sample was measured. Different techniques were used to determine the properties of carbon and of the surface functional groups (Total Carbon, XRD, ATR-FTIR) and leachable organic matter. Also, sorption of the methylene blue dye solution has been studied, which is an indication of mesopores for each biochar. Molasses number was also determined, as this is an indicator of macropores. Finally, the chlorine removal rate was determined for each type of biochar. The experiments marked that the change in mass of biochars has stopped after three hours at 50 °C in the drying oven. The measured moisture content ranged from 6 to 11%. The specific surface area of our materials, calculated through the BET equation, for low temperature biochars (e.g., 28 m²/g, at 350 °C), is much lower than that of high temperature pyrolyzed biochar (e.g., 286 m²/g, at 850 °C). The pH value ranged from 7 to 10. The electrical conductivity values of samples ranged from 800 μS/cm to 2.55 mS/cm, and these decreased during the measurement after the second wash with deionized water. Crystallinity increased with increasing pyrolysis temperature whereas the number of functional groups decreased. MSR biochars produced at temperatures equal or higher than 750 °C demonstrate different characteristics to the ones produced at lower temperatures. Full article

The urgent need to mitigate carbon dioxide (CO₂) emissions from fossil-fuel-based electricity generation has driven research into advanced materials for post-combustion carbon capture. This paper presents a modified solvothermal technique to synthesize zinc (Zn) and magnesium (Mg) based MOF-74 suitable for CO₂ capture from coal-fired power plants. The materials were synthesized through a solvothermal method using N,N-dimethylformamide (DMF) as the primary solvent, and subsequently characterized using Brunauer–Emmett–Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and thermogravimetric analysis (TGA). Both MOFs contained oxygen-containing functional groups and were thermally stable up to 430 °C and 600 °C respectively, making them ideal for carbon capture. The low-pressure N₂-BET surface areas were 55 m²/g and 24.73 m²/g. In conclusion, the Zn material had a mesoporous structure, making it more favorable for carbon capture. It was found that prolonged synthesis time weakened the MOF structure. Future work should experimentally evaluate CO₂ capture from coal-derived flue gas using Zn/Mg-MOF-74 materials, investigating adsorption behavior and kinetics through isotherm and kinetic models, while also assessing the effect of varying Zn: Mg ratios under optimized synthesis conditions. Full article

This study investigates orange peel valorisation through KOH pre-treatment and high-temperature pyrolysis (800 °C) to develop a highly porous activated char for the efficient removal of phenolic compounds, specifically 2,4-dinitrophenol (DNP) and aminophenol (AP), from water. The main objective of the study is to synthesise high-surface area activated char from orange peel and investigate its performance for the adsorption of DNP and AP from water. The synthesised adsorbent exhibited a Brunauer–Emmett–Teller (BET) specific surface area of 965 m²/g, contributing to its excellent phenol adsorption efficiency. Batch adsorption experiments were performed, and a maximum removal efficiency of 99% and 92% was observed at pH 4 and 7 with initial concentration 50 mg/L, contact time 60 min, and adsorbent dosage 0.6 g/L, for DNP and AP, respectively. The adsorption process was described by the Langmuir isotherm model (R² = 0.99), indicating monolayer adsorption and followed pseudo-second-order kinetics, achieving a maximum adsorption capacity of 366 mg/g for DNP and 341 mg/g for AP. Furthermore, DFT analysis revealed that DNP possesses a lower HOMO-LUMO energy gap (−0.54 eV), favouring a stronger adsorption interaction, whereas AP exhibited a relatively higher energy gap (−0.27 eV), corresponding to its comparatively lower adsorption capacity. Overall, the findings demonstrates that a single step chemical-thermal conversion of orange peel into biochar-based adsorbent offers a sustainable pathway for the removal of phenolic compounds from water. Full article

Accumulation of tetracycline (TC) in aquatic environments poses a significant threat to human health and ecosystems, driving the need for efficient removal technologies. Two-dimensional metal–organic frameworks (2D MOFs) are promising adsorbents due to their tunable structures and abundant active sites. In this work, three 2D MOFs, M₃(HHTP)₂ (M = Cu, Ni, Co), were synthesized via a solvothermal method. Among them, Cu₃(HHTP)₂ exhibited superior TC adsorption with a maximum capacity of 302.84 mg/g. The adsorption process, best described by the Langmuir isotherm and pseudo-second-order kinetic models, indicates chemisorption. Mechanistic investigations reveal that the high-activity coordination sites formed by Cu²⁺ due to Jahn–Teller distortion enable strong coordination with TC. This is identified as the key factor governing the differential adsorption performance among the three MOFs. Simultaneously, the surface functional groups facilitate hydrogen bonding, and the advantageous pore structure of the material itself, together forming a synergistic adsorption. This work not only elucidates the microscopic mechanism behind the efficient adsorption of TC by Cu₃(HHTP)₂ but also, through comparative analysis of isostructural MOFs, confirms the decisive role of metal center electronic structure in modulating the adsorption behavior of 2D MOFs. The insights gained from this study may serve as a reference for the design of 2D high-performance adsorbents. Full article

This study evaluates the effectiveness of natural zeolite (Shankhanai deposit, Kazakhstan) as a functional hydroponic substrate compared to a commercial foamed-glass control (GrowPlant). Using the Nutrient Film Technique (NFT), we assessed the growth and metabolic responses of Medicago sativa L. and three cultivars of Lactuca sativa L. Brunauer–Emmett–Teller (BET) analysis confirmed that zeolite (particle size 3.70 ± 1.20 mm) possesses a high specific surface area (21.80 m²/g), significantly exceeding the control (0.49 m²/g). This structure ensured superior moisture retention and cation exchange, even after a moderate decrease in surface area to 16.66 m²/g post-cultivation due to organic pore-filling. In M. sativa experiments, zeolite increased seedling viability and promoted a more branched root system compared to the artificial substrate. Gas chromatography–mass spectrometry (GC–MS) metabolic profiling of L. sativa revealed a significant substrate-driven reprogramming: zeolite increased the relative proportion of fatty acids and their derivatives (up to +51.27% in May King variety roots), suggesting membrane-protective adaptation. Genotype-specific responses were observed, with the Yeralash cultivar showing increased polyol synthesis (+2.93%) for osmoregulation. The results demonstrate that natural zeolite is an efficient, stable substrate for intensive hydroponics, optimizing root development and physiological stability through enhanced nutrient and water management. Full article

This study investigates the potential of pure chitosan powder as an effective, sustainable, and low-cost adsorbent for the removal of synthetic dyes from aqueous media. The work demonstrates the potential of pristine chitosan for practical wastewater treatment applications by adsorbing two commonly used textile dyes, methyl orange (MO) and methylene blue (MB). To elucidate the adsorption mechanism, chitosan was comprehensively characterized using zeta potential analysis, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM–EDX), Thermogravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) surface area analysis, and point of zero charge (pHpzc) determination. FTIR analysis revealed notable shifts in –NH₂ and –OH functional groups after dye adsorption, confirming their involvement in electrostatic interactions and hydrogen bonding with MO and MB. SEM images demonstrated significant surface morphological changes following adsorption, while EDX spectra confirmed successful dye uptake through the appearance of sulfur and nitrogen signals characteristic of MO and MB, respectively. Zeta potential and pHpzc results explained the strong pH-dependent adsorption behavior, highlighting favorable electrostatic attraction between chitosan and the ionic dyes. The optimum adsorption conditions were achieved at adsorbent dosages of 0.5 g for MO and 1.0 g for MB, a contact time of 30 min, initial dye concentrations of 20 and 100 mg/L, and solution pH values of 3 for MO and 9 for MB at room temperature. The adsorption data fit the Langmuir isotherm model, indicating monolayer adsorption on a homogeneous chitosan surface, with maximum adsorption capacities of 7.843 mg/g for MO and 7.605 mg/g for MB. Kinetic studies showed that adsorption followed the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Thermodynamic analysis indicated that the adsorption process was endothermic and non-spontaneous under the investigated conditions. In conclusion, these findings demonstrate that unmodified chitosan is a practical, eco-friendly adsorbent for dye removal, achieving removal efficiencies comparable to many modified chitosan composites, and represents a promising candidate for sustainable wastewater treatment. Full article

This study aims to develop an innovative electrochemical genosensor based on activated biochar (ABC) derived from the biomass of the seaweed Sargassum spp. The synthesis process begins with the pyrolysis of Sargassum spp. at 500 °C to obtain biochar (BC), which is chemically activated with nitric acid (HNO₃). The physicochemical properties of the resulting material, such as morphology and surface area, were characterized using techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and the Brunauer–Emmett–Teller (BET) method for surface area. BET results showed an increase in surface area from 22.9367 ± 0.0879 m²/g (BC) to 159.2915 ± 2.2641 m²/g (ABC). For the development of the genosensor, a hydrolyzed collagen gel matrix enriched with ABC is created. This nanostructured, biocompatible mixture is used to immobilize a DNA probe on a graphite electrode, employing the large surface area of ABC and the formation of a functional HC-based coating. The system’s viability was evaluated by cyclic voltammetry (CV), which showed changes in the maximum anodic peak current (Ipa) during fabrication: 27.78 ± 1.87 μA for the bare electrode, 35.25 ± 1.24 μA for ABC 30%, and 39.25 ± 1.84 μA for HC + ABC 30%. After ssDNA immobilization and hybridization to dsDNA, Ipa decreased to 28.81 ± 1.565 μA and 23.10 ± 1.25 μA, respectively. Finally, hematoxylin (Hx) was used as an intercalating indicator from hybridization, reducing the maximum anodic peak current to 15.51 ± 1.13 μA, consistent with additional interfacial limitations associated with dsDNA formation. Overall, the developed system demonstrates a sustainable, promising platform for molecular diagnostics in electrochemical DNA biosensor development. Full article

Porous Cu/Cu₂O catalytic materials with a unique pore structure were successfully synthesized via a one-step solvothermal method using Cu-MOF-74 as the intermediate, followed by induced collapse and oxidation. The structural properties and catalytic performance of the as-prepared Cu/Cu₂O materials in the thermal decomposition of ammonium perchlorate (AP) were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, and thermogravimetry–differential scanning calorimetry (TG-DSC) combined with in situ thermogravimetry–mass spectrometry (TG-MS). The results show that the specific surface area of the Cu/Cu₂O material is 46.6697 m²/g, and the average pore diameter is 9.4608 nm. Owing to the synergistic effect of Cu⁰/Cu⁺ dual sites on promoting electron transfer during AP thermal decomposition, the Cu/Cu₂O catalyst exhibits excellent catalytic activity. Specifically, at a heating rate of 20 °C/min, the addition of 2 wt% Cu/Cu₂O reduces the high-temperature decomposition temperature of AP from 473.1 °C to 321.1 °C (a decrease of 151.0 °C), lowers the thermal decomposition activation energy from 296.63 kJ/mol to 253.21 kJ/mol (a reduction of 43.42 kJ/mol), and increases the heat release by 617.8 J/g compared to pure AP. TG-MS analysis revealed that Cu/Cu₂O accelerates the decomposition of AP by adsorbing and activating NH₃ and HClO₄ generated in the low-temperature decomposition stage, facilitating the formation of reactive intermediates such as ClOₓ and promoting the oxidation of nitrogen-containing species. This study demonstrates that the porous Cu/Cu₂O material synthesized by the one-step solvothermal method is a promising catalyst for enhancing the thermal decomposition performance of AP in solid propellants. Full article