Search Results (3,430)

Freshwater scarcity driven by population growth and industrial demand has increased reliance on desalination, where reverse osmosis (RO) is widely applied due to its high separation efficiency. Membrane performance is governed by the balance between water permeability and solute rejection, and attempts to improve this relationship have focused on incorporating nanomaterials to modify membrane structure and transport behavior. In this study, a computational investigation was carried out for thin-film composite (TFC) membranes incorporating graphene oxide–poly(amidoamine) (GO–PAMAM) within the polysulfone substrate to examine its influence on transport under RO conditions. A two-dimensional model was implemented in COMSOL Multiphysics by coupling the Laminar Flow and Transport of Diluted Species interfaces, while permeation across the membrane was described using a solution–diffusion framework parameterized by experimentally determined salt permeability coefficient. Variation in GO–PAMAM loading (0–0.10 wt%) was introduced through intrinsic permeability parameters, enabling direct comparison with experimental data. The simulations reproduced the observed trends, with the membrane containing 0.06 wt% GO–PAMAM showing higher salt rejection, increasing from 78.16% to 90.08% relative to the pristine membrane. The model predicted lower permeate-side solute concentration and a decrease in salt rejection along the membrane length. Model predictions agreed with experiments, with mean relative errors of 1.23% for salt rejection and 7.41% for water flux, demonstrating the ability of the model to capture transport behavior in GO–PAMAM-modified TFC membranes. Full article

Regulatory T cells (Tregs) play a key role in immune tolerance and are promising targets for treating immune-mediated diseases. This study investigated the direct effects of PEGylated graphene oxide nanoparticles (LP-GO, BP-GO at 5–25 μg/mL) and fullerenol C₆₀(OH)₂₄ (25–200 μg/mL) on human Treg viability and differentiation in vitro. Tregs were induced from peripheral blood CD4⁺ T cells using IL-2, TGF-β, and CD2/CD3/CD28 activation beads for 72 h with nanoparticles. Assessments included viability, apoptosis (Zombie aqua/Annexin V), phenotype (CD45⁺CD4⁺CD25⁺CD127^dim/−FOXP3⁺), nanoparticle sorption (intrinsic fluorescence), and IL-10 production. Neither PEGylated graphene oxide nor fullerenol C₆₀(OH)₂₄ affected T-helper (CD4⁺) viability (95.35–96.15%) nor early/late apoptosis levels. Despite this, we found a decrease in the percentage of CD4⁺ cells in cultures exposed to 50–200 μg/mL of fullerenol C₆₀(OH)₂₄. The percentage and absolute number of Treg cells decreased with 100–200 μg/mL of fullerenol, while IL-10 levels declined following treatment with 200 μg/mL of the same nanoparticles. Graphene oxide nanoparticles showed virtually no localization within or on cells. However, T helper and Treg cells demonstrated concentration-dependent sorption of fullerenol C₆₀(OH)₂₄ at concentrations of 100–200 μg/mL without a reduction in viability. These findings demonstrate good in vitro biocompatibility of the nanoparticles at pharmacological concentrations up to 25 μg/mL, alongside the inhibition of Treg differentiation with 100–200 μg/mL of fullerenol C₆₀(OH)₂₄. Full article

Graphene oxide (GO) can improve cementitious materials, but its effectiveness often differs among commercial products even at the same nominal dosage. This study proposes an optical microscopy-based framework for evaluating the initial dispersion quality of commercial GO suspensions before cement mixing. Under fixed slide preparation, imaging, and image-processing conditions, optical microscopy was used as a geometric dispersion-evaluation tool rather than a direct chemical characterization method. Three image-derived features, namely projected boundary richness, coarse-agglomerate fraction, and spatial dispersion uniformity, were integrated into an optical initial dispersion quality index, D_j. The framework was applied to five commercial GO products at a fixed dosage of 0.03 wt% of binder. The D_j-based ranking was Brand 1 > Brand 2 > Brand 3 > Brand 4 > Brand 5, and remained unchanged when the coarse-agglomerate threshold varied from 20 to 100 μm². Bootstrap resampling confirmed the robustness of the ranking. The 3-day compressive strength increased from 51.1 MPa for the control mixture to 52.6~60.8 MPa for GO-modified mortars, corresponding to enhancement ratios of 3.1~19.2%. The strength-enhancement ranking was identical to the optical dispersion ranking, with a Spearman rank correlation coefficient of ρ_s = 1.0. The proposed D_j index provides a practical pre-mixing screening tool for comparing commercial GO products before strength testing or detailed physicochemical characterization. Full article

Cathinone and its synthetic derivatives are among the most popular drugs worldwide. However, the literature provides data on the medicinal and cytotoxic potential of some of these compounds. These data are extremely limited due to the need to obtain additional permits for laboratory studies. Consequently, the therapeutic potential of cathinones may not have been fully explored. Furthermore, the literature provides data on the reduction or reversal of undesirable biological properties of drugs encapsulated in a bio-compatible carrier and administered through targeted therapy. The current study presents preliminary theoretical and experimental tests for further research on target cathinone–graphene–oxide complexes. A non-psychotropic cathinone model—o-fluorophenylacetic acid—was used. The NMR properties (chemical shifts, spin–spin coupling constants, and T₁ relaxation times) of graphene oxide–F-derivative complexes were measured at an acidic and neutral pH. To analyze the structure and stability of the possible complexes in different environments, molecular modelling was performed with simplified graphene oxide models using density functional theory. Experimental data were compared with theoretical values, and the most stable structures that may account for the observed spectral properties of the studied complexes were presented. The obtained data indicate a stronger tendency towards the formation and stabilization of GO-2-fluorophenylacetic acid complexes in a neutral environment. Full article

Flexible transparent conductive films (TCFs) and their applications have attracted extensive interest. Silver nanowires (AgNWs) have been explored to replace conventional indium tin oxide (ITO) due to their high optical transmittance and superior electrical conductivity. Nevertheless, AgNWs tend to oxidize under ambient conditions, which weakens the conductive network and limits long-term performance. Spraying reduced graphene oxide (rGO) can stabilize the conductive network and inhibit oxidation, thereby enhancing the overall properties of the films. In this work, rGO/AgNW/PET TCFs were prepared using a spray-coating approach. The transmittance of the rGO/AgNW/PET TCFs was measured at 77% at 550 nm, accompanied by a sheet resistance of 6.8 Ω/sq. The films achieved the surface temperature of 95 °C at 6 V with stable operation while also achieving an electromagnetic interference shielding effectiveness of 27 dB. This structural design improves both performance and stability, offering great potential for flexible TCFs in advanced optoelectronic applications. Full article

Currently, dual-functional composites that simultaneously provide structural support and energy storage capabilities have garnered significant attention. However, the challenge of balancing mechanical strength and energy storage performance remains a limiting factor for their application. Herein, a novel N-doped reduced graphene oxide/nano-sulfur@porous SiC (N-rGO/S@porous SiC) composite material was successfully prepared by in situ embedding N-rGO supported with nano-sulfur into a 3D-printed porous SiC scaffold via a hydrothermal synthesis approach. The hierarchical porous structure composed of SiC and N-rGO facilitates mass transport of the liquid electrolyte. Benefiting from the high strength of SiC, the novel material achieves a compressive strength of 93.5 MPa. Benefiting from the synergistic effect of the N-rGO/S composite and the high ionic conductivity of the liquid electrolyte, the electrode material delivers superior electrochemical energy storage performance, achieving a specific capacitance of 800.7 mF/cm² at a current density of 1 mA/cm², together with remarkable rate capability and good cycling stability. To our knowledge, this composite exhibits a high level of integrated properties. More importantly, the strategy of integrating porous, high-strength supports with high-performance electrode materials opens new avenues for the synthesis of structure-energy-storage dual-functional composites. Full article

The development of high-performance adsorbents for treating dye-laden wastewater necessitates a deep understanding of structure–property relationships. This study presents a systematic investigation into the role of carbon material dimensionality (0D biochar, BC; 1D carbon nanotubes, CNT; 2D graphene oxide, GO) in modulating the properties of a dual physically crosslinked sodium alginate/polyacrylamide (SA/PAM) hydrogel for methylene blue (MB) adsorption. A series of composite hydrogels was fabricated via a sequential physical crosslinking strategy. Comprehensive characterization confirmed the successful incorporation and dispersion of carbon materials within the dual network. The three hydrogels showed good mechanical properties. Under the conditions of 25 °C, an initial MB concentration of 100 mg/L, and pH 10–11, the incorporation of carbon materials enhanced the adsorption capacity, with maximum adsorption capacities of 411.5, 410.6, and 422.8 mg/g for BC-H, GO-H, and CNT-H, respectively. Coexisting constituents in real water samples reduce adsorption capacity via competitive adsorption and interfacial interference. After five consecutive adsorption–desorption cycles, the adsorption capacities of BC-H, GO-H, and CNT-H decreased to 57.7%, 67.2%, and 61.7% of their initial values, respectively. Adsorption isotherm and kinetic studies revealed that the process followed the Langmuir model and pseudo-second-order kinetics, indicative of monolayer chemisorption. Mechanistic analysis identified synergistic contributions from electrostatic attraction, π-π stacking, and physical entrapment. Physical structural changes and chemical site occupation are the main reasons for the decrease in the adsorption performance of hydrogels during cyclic use. This work provides a rational design strategy for advanced adsorbents and a theoretical foundation for efficient dye wastewater remediation. Full article

Graphene oxide (GO) has been widely investigated as a nanoreinforcement for cementitious composites; however, its effectiveness depends on stable dispersion within the highly alkaline, calcium-rich environment of fresh cement paste. This study evaluates the dispersion behaviour of GO in deionised (DI) water and saturated calcium hydroxide (Ca(OH)₂) under controlled conditions and assesses the effectiveness of anionic and cationic surfactants in both environments. GO was synthesised using the modified Hummers method and verified by comprehensive physicochemical characterisation. Dispersion stability was assessed using UV-Vis spectroscopy at GO concentrations of 0.04–0.08 mg/mL in DI water, and the 0.08 mg/mL system was further studied in saturated Ca(OH)₂ with and without sodium dodecylbenzene sulphonate (SDBS) and cetyltrimethylammonium bromide (CTAB) at a 1:1 mass ratio. Zeta potential and dynamic light scattering measurements were performed to understand the relation between the surface charge and agglomeration of GO. In DI water, GO retained close to 70% of its initial absorbance after 60 min, and both surfactants improved retention to above 90%. In saturated Ca(OH)₂, retention fell to approximately 40%, and neither surfactant restored stability despite producing zeta values that would conventionally support stable dispersion. The findings indicate that GO aggregation in calcium ion (Ca²⁺)-rich alkaline environments is not governed by net surface charge alone, consistent with the established mechanism of Ca²⁺ chemical cross-linking with GO carboxyl groups. Full article

This study develops high-performance ammonia sensors based on composites of metal-organic frameworks (MOF-808 and MOF-818) with reduced graphene oxide (rGO). Two sensor architectures were fabricated: interdigital electrodes and silicon micropillar arrays. The MOF-808/rGO composite demonstrated superior sensing performance for 40 ppm NH₃ at room temperature, with faster response kinetics and higher sensitivity compared to pristine rGO and MOF-818/rGO. Silicon micropillar array sensors showed enhanced performance through optimized periodic arrangements, while oxygen plasma surface modification improved both sensor types. Comprehensive testing confirmed that the MOF-808/rGO sensor maintains reliable NH₃ detection at concentrations as low as 5 ppm under high humidity conditions, exhibiting excellent stability and selectivity. These findings provide valuable insights for developing advanced gas sensors for environmental monitoring applications. Full article

This study presents a hierarchical conductive-network strategy to overcome the performance trade-off in cement structural supercapacitors (CSSCs). By incorporating one-dimensional carbon nanotubes (CNTs) and two-dimensional graphene oxide (GO) into Portland cement, we simultaneously enhance its electrochemical and mechanical properties. The approach exploits the complementary roles of the two nanomaterials: CNTs establish a three-dimensional percolation network that facilitates electron transport, while GO promotes formation of a denser calcium silicate hydrate (C-S-H) gel and refines the pore structure by complexing with calcium ions, thereby improving ionic pathways. The k12gc sample attains a specific capacitance of 66.8 F g⁻¹ at 0.1 mA cm⁻², a 58.4% rise in conductivity and a 63% reduction in charge-transfer resistance. At the same time, the composite reduces harmful macropores by 27.9% and strengthens the material, with compressive and flexural strengths increasing by 4.8% and 8.3%, respectively. This work establishes a rational design principle based on functional division between CNTs and GO for developing high-performance, multifunctional CSSCs. Full article

This study reports the development of a novel thin-film nanocomposite (TFN) reverse osmosis (RO) membrane with a surface functionalized using graphene oxide (GO) and polydopamine (PDA). GO was synthesized using a modified Hummers’ method and integrated into a PDA-coated commercial RO membrane. The membranes were treated with UV light for varying durations to enable crosslinking of GO nanoparticles to the membranes. The modified membranes showed improved pure water permeability (PWP) and salt rejection compared to the pristine membrane. The resulting RO membrane, which was exposed to 60 min of UV and contained 0.02 g of GO, achieved the best performance, with a PWP of 23.8 L m⁻² h⁻¹ bar⁻¹ and a salt rejection of 96%. Antiscaling and antifouling properties were notably enhanced, as indicated by stable flux under silica scaling and decreased bacterial growth. These results suggest that PDA-GO functionalization is a promising approach for improving membrane durability and efficiency in desalination processes. Full article

The increasing environmental pollution with emergent pollutants has led to the necessity to develop various structures for sensory applications used in water monitoring processes. In this context, this study presents a composite structure based on titanium foil/titanium dioxide/reduced graphene oxide functionalized with gold ions (Ti/TiO₂-Au/rGO) obtained by a simple and efficient spin-coating method, successfully applied in electrochemical doxorubicin detection processes. The synthesis protocol first involves etching the titanium foil to form a Ti/TiO₂ substrate, followed by the synthesis of the TiO₂-Au/rGO solution, which was deposited by a spin-coating technique on the surface of the Ti/TiO₂ support, to form electrodes based on a Ti/TiO₂-Au/rGO composite structure. The structure and morphology of the as-synthesized composites were investigated in detail using X-ray analysis, Raman spectroscopy, and scanning electron microscopy coupled with an EDX. Furthermore, to determine the electroactive surface area and apparent diffusion coefficient of the composite structures, the electrochemical behavior was evaluated by CV in a 1 M KNO₃ and in the presence of 4 mM K₃Fe(CN)₆. By using electrochemical impedance spectroscopy (EIS) in 0.1 M NaOH supporting electrolyte and within a frequency range of 0.1–10,000 Hz and a voltage of 10 mV, the charge transfer resistance was also investigated. The potential application in electroanalysis of the electrodes was tested by CV for the detection of the DOX pollutant in 0.1 M NaOH and 1–5 mg L⁻¹ DOX. The obtained results provide new insights into the development of electrochemical sensors for applications in water treatment processes. Full article

Reduced graphene oxide (rGO) wrapped with poly(styrenesulfonate) (PSS) forms a stable hybrid material (rGO/PSS) capable of producing ultrathin films with promising barrier properties for Direct Methanol Fuel Cell (DMFC) applications. These films aim to mitigate methanol crossover, one of the major limitations of DMFC technology. In this work, we investigate the mechanisms underlying the methanol barrier effect of rGO/PSS, while maintaining water permeability. Classical Molecular Dynamics simulations were employed to explore the structural and dynamic properties of rGO/PSS at different polymer ionization fractions in a solvent mixture of water, methanol, and hydronium. The influence of the sulfonation fraction on film self-assembly was analyzed, including its impact on PSS conformation, rGO sheet distribution, and PSS–rGO interactions. Finally, the effect of the rGO/PSS structure on solvent diffusion was investigated, and the mechanisms responsible for the selective transport of methanol were elucidated. Full article

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive malignancy, characterized by rapid progression, early metastasis, and resistance to conventional therapies. Increasing evidence indicates that the behavior of residual tumor cells is strongly influenced by physicochemical properties of their microenvironment. Surface engineering strategies using nanostructured materials may therefore represent a complementary approach to modulating cancer cell activity. In this study, we investigated whether a graphene oxide (GO) aerosol nanofilm modifies the biological behavior of PDAC cells in vitro. The GO aerosol (4.5 g/L) was characterized using STEM, DLS, zeta potential measurements, LIBS, EDX, and FTIR spectroscopy. Ultrastructural analysis revealed thin, wrinkled GO sheets forming partially overlapping lamellar structures, while physicochemical characterization confirmed a highly oxidized stable nanomaterial. Human PDAC cell lines (BxPC-3 and AsPC-1) were cultured on GO-modified substrates to assess morphology (SEM), metabolic activity (XTT assay), migratory capacity (wound healing assay over 72 h), and expression of genes related to proliferation and epithelial–mesenchymal transition (EMT) by RT-qPCR. GO nanofilm significantly reduced cell viability and inhibited migration in both cell lines. SEM analysis demonstrated shortened cytoplasmic projections and altered membrane integrity. Gene expression profiling revealed cell line-dependent transcriptional responses, including modulation of components of the PI3K/AKT/mTOR pathway and EMT-associated markers. Collectively, our findings demonstrate that GO aerosol nanofilm alters PDAC cell morphology, viability, and migratory behavior in vitro. Surface-mediated modulation of tumor cell activity may represent a promising adjunct strategy for limiting residual cancer cell survival and metastatic potential. Full article

This study examines the effects of graphene oxide (GO) on the hydration behaviour, microstructure, and mechanical properties of Portland cement-based materials. Cement pastes and mortars incorporating GO at dosages of 0.0005%, 0.005%, and 0.05% by weight of cement were analysed through thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), and mechanical strength testing. TGA results indicate that GO exerts a time-dependent influence on cement hydration. At early ages, GO slightly retards hydration, evidenced by lower C–S–H and CH content in GO-containing samples at 2 and 7 days, attributed to water adsorption by its oxygen-containing functional groups. At later curing ages (28–90 days), TGA results show greater C–S–H and CH weight losses in GO-modified samples compared to the reference, consistent with GO acting as a water reservoir and nucleation site. XRD and SEM results confirm that GO incorporation leads to a reduction in CH crystal size, a denser and more homogeneous microstructure, and fewer pores and microcracks. Mechanical tests revealed that GO contents of 0.0005% and 0.05% produced the most significant improvements, with increases of up to 9% in compressive strength and 16% in flexural strength at 90 days compared with the control specimens. In summary, the incorporation of low GO dosages effectively refines cement microstructure, enhances long-term hydration, and improves mechanical performance, demonstrating GO’s potential as a strength- and durability-enhancing nanomaterial for cementitious composites. Full article