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This study explores the potential of graphene oxide (GO) as an additive in waterborne polyurethane (WPU) resins to create eco-friendly coatings with enhanced anticorrosive properties. Traditionally, WPU's hydrophilic nature has limited its use in corrosion-resistant coatings. We investigate the impact of incorporating various GO concentrations (0.01, 0.1, and 1.3 wt%) and functionalizing GO with ethylenediamine (EDA) on the development of anticorrosive coatings for carbon steel. It was observed, by potentiodynamic polarization analysis in a 3.5% NaCl solution, that the low GO content in the WPU matrix significantly improved anticorrosion properties, with the 0.01 wt% GO-EDA formulation showing exceptional performance, high Ecorr (−117.82 mV), low icorr (3.70 × 10−9 A cm−2), and an inhibition corrosion efficiency (η) of 99.60%. Raman imaging mappings revealed that excessive GO content led to agglomeration, creating pathways for corrosive species. In UV/condensation tests, the 0.01 wt% GO-EDA coating exhibited the most promising results, with minimal corrosion products compared to pristine WPU. The large lateral dimensions of GO sheets and the cross-linking facilitated by EDA enhanced the interfacial properties and dispersion within the WPU matrix, resulting in superior barrier properties and anticorrosion performance. This advancement underscores the potential of GO-based coatings for environmentally friendly corrosion protection. [ABSTRACT FROM AUTHOR]

This paper presents a recent investigation into the electromechanical behavior of thermally reduced graphene oxide (rGO) as a strain sensor undergoing repeated large mechanical strains up to 20.72%, with electrical signal output measurement in multiple directions relative to the applied strain. Strain is one the most basic and most common stimuli sensed. rGO can be synthesized from abundant materials, can survive exposure to large strains (up to 20.72%), can be synthesized directly on structures with relative ease, and provides high sensitivity, with gauge factors up to 200 regularly reported. In this investigation, a suspension of graphene oxide flakes was deposited onto Polydimethylsiloxane (PDMS) substrates and thermally reduced to create macroscopic rGO-strain sensors. Electrical resistance parallel to the direction of applied tension ( x ^ ) demonstrated linear behavior (similar to the piezoresistive behavior of solid materials under strain) up to strains around 7.5%, beyond which nonlinear resistive behavior (similar to percolative electrical behavior) was observed. Cyclic tensile testing results suggested that some residual micro-cracks remained in place after relaxation from the first cycle of tensile loading. A linear fit across the range of strains investigated produced a gauge factor of 91.50(Ω/Ω)/(m/m), though it was observed that the behavior at high strains was clearly nonlinear. Hysteresis testing showed high consistency in the electromechanical response of the sensor between loading and unloading within cycles as well as increased consistency in the pattern of the response between different cycles starting from cycle 2. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal is regarded as a next-generation anode material owing to its high energy density. However, issues such as dendritic growth and volume changes during charging and discharging pose significant challenges for commercialization. We propose using lithiophilic reduced graphene oxide (rGO) and carbonized zeolite imidazolate framework-8 (C-ZIF-8) composites as host materials for Li to address these problems. The rGO/C-ZIF-8 composites are synthesized through a simple redox reaction followed by carbonization and are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The roles of chemical composition, characteristics, and morphology are demonstrated. As a result of these favorable structural and functional properties, the Li symmetric cell with rGO/C-ZIF-8 exhibits a stable voltage profile for more than 100 h at 1 mA cm−2 without short-circuiting. A relatively low Li plating/stripping overpotential of ~101.5 mV at a high current density of 10 mA cm−2 is confirmed. Moreover, a rGO/C-ZIF-8-Li full cell paired with a LiFePO4 cathode demonstrates good cyclability and rate capability. [ABSTRACT FROM AUTHOR]

In the actual context of growing concerns over sustainability and energy efficiency, Phase Change Materials (PCMs) have gained attention as promising solutions for enhancing energy storage and release efficiency. On another hand, materials based on graphene oxide (GO) have proven antibacterial activity, biocompatibility, efficiency in microbial growth inhibition, and pollutant removal. Integrating nanoparticles into PCMs and creating Nano-Enhanced Phase Change Materials (NEPCMs) have opened new horizons for optimizing the performance of these systems and sustainable development. The key objective of this work is to gain insight into NECPMs, which are used in solar wall systems to enhance solar energy storage. Paraffin RT31 was mixed with Cu nanoparticles, graphene oxide (GO), and Cu-decorated GO (Cu@GO) at loading ratios ranging from 1% to 4% (w/w nanoparticles with respect to RT31). The compositions were characterized through Differential Scanning Calorimetry (DSC) and rheology tests. The decoration of the carbon-based nanoparticles was performed using the ultrasonication procedure, and the decoration efficiency was confirmed through X-ray Photoelectron Spectroscopy (XPS). The rheologic measurements were performed to correlate the flow behavior of the NEPCM with their composition at various temperatures. The study methodically investigated these composites' latent heat values, phase change peak temperatures, and solidification phase change temperatures. Compared to pure paraffin, the solidification of the formulations obtained using Cu@GO exhibits the largest increase in latent heat, with a 12.07% growth at a concentration of 2%. Additionally, at a 4% concentration of NEPCM, the largest increase in thermal conductivity was attained, namely 12.5%. [ABSTRACT FROM AUTHOR]

Herein, we introduce a simple precipitation method for preparing graphene oxide–silver nanoparticle (GO/AgNP) composites, utilizing Calendula officinalis (C. officinalis) seed extract as both a reducing and stabilizing agent. Our research combines the sustainable preparation of graphene oxide (GO) with the green synthesis of silver nanoparticles (AgNPs), aiming to explore the potential of the obtained composite as a novel antibacterial material. To establish a benchmark, the synthesis was also performed using sodium citrate, a conventional reducing agent. The resultant GO/AgNP composites were characterized through several analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD), infrared (IR) spectroscopy, and ultraviolet–visible (UV-vis) spectroscopy, confirming the successful functionalization of GO with AgNPs. The antibacterial effectiveness of the composites was systematically assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with nanoparticle concentrations spanning from 0 to 250 µg/mL, utilizing mostly disk diffusion and colony-forming unit (CFU) count assays. The AgNPs were characterized by a size range of 15–50 nm. Notably, the GO/AgNP composite prepared using C. officinalis seed extract demonstrated superior antibacterial activity at all tested concentrations, outperforming both pure GO and the GO/AgNP composite prepared with sodium citrate. The most pronounced antibacterial effect was observed at a concentration of 32.0 µg/mL. Therefore, this innovative synthesis approach may offer a valuable contribution to the development of new therapeutic agents to combat bacterial infections, suggesting further exploration into antibacterial coatings or potential drug development. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of incorporating different concentrations of graphene oxide (GO) nanoparticles on the mechanical properties of a resin-modified glass ionomer cement (RMGIC). A commercial RMGIC (Resiglass R, Biodinâmica) was modified by incorporating 0.1% and 0.5% (by weight) of GO into the powder's material. An unmodified RMGIC was used as a control group. Powder samples were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Specimens were fabricated and subjected to flexural strength (n = 15), modulus of elasticity (n = 15), Vicker's microhardness (n = 10), and surface roughness tests (n = 10). Data were analyzed using one-way ANOVA and Tukey's post hoc test (α = 5%). Experimental groups' powder demonstrated a homogeneous dispersion of GO. No statistically significant difference was observed in flexural strength (p = 0.067) and modulus of elasticity (p = 0.143) tests. The groups containing 0.1% and 0.5% GO showed significantly higher microhardness and lower surface roughness values (p < 0.001) compared to the control group. The incorporation of GO nanoparticles at concentrations of 0.1% and 0.5% improved the microhardness and surface roughness without negatively affecting the flexural strength and modulus of elasticity of an RMGIC. [ABSTRACT FROM AUTHOR]

To explore the effect of acid rain corrosion on the cohesion performance of asphalt and its mechanism, graphene oxide (GO) was used to modify epoxy asphalt and 70# base asphalt, TAFPACK Super (TPS) high viscosity asphalt and epoxy asphalt were used as the control group, the periodic dry–wet cycle immersion test was used to simulate the acid rain environment to study the effect of acid rain on the physical properties, composition, cohesion and adhesion between different asphalt binders and aggregates. Furthermore, combined with aging test, the aging resistance of each asphalt after acid corrosion was investigated. The results show that acid rain corrosion can significantly decrease the adhesion between asphalt and aggregates and the cohesion of asphalt itself, resulting in serious moisture damage of asphalt. GO modified epoxy asphalt has better acid rain corrosion resistance than other asphalt. GO improves the cross-linking density between asphalt molecules. The polar groups and low shrinkage thermosetting resin of GO modified epoxy asphalt make it has excellent adhesion and high cohesion, which can effectively resist moisture erosion, peeling and temperature stress cracking, thus effectively resist the corrosion of acid rain. Aging deteriorates the performance of asphalt binder and decreases its acid corrosion resistance. GO modified epoxy asphalt can effectively inhibit the aging of asphalt binder, thus resisting the deterioration caused by aging. [ABSTRACT FROM AUTHOR]

A composite based on Fe3O4 nanoparticles, graphene oxide, and a ionic liquid (1-butyl-3-methylimidazolium-2-carboxylate) is proposed as a sorbent for the extraction of bisphenol A (BPA) from bottom sediments by matrix solid-phase dispersion (MSPD). The saturation magnetization of the synthesized sorbent is 34 emu/g. Grinding of bottom sediments and subsequent grinding with a sorbent was carried out in a ball mill. Some stages of MSPD were partially automated, in particular, the procedures of magnetic separation, BPA desorption, and sorbent regeneration. The recovery of BPA under the experimentally selected conditions (sorbent mass 0.5 g, time required to grind the sorbent 5 min) was 94%. The sorbent can withstand four sorption-desorption cycles without a loss of sorption capacity. To purify the matrix from interferents, washing with n-heptane was proposed. Bisphenol A was determined by gas chromatography–mass spectrometry after derivatization with acetic anhydride. The analytical characteristics of the method were established using model samples of bottom sediments artificially contaminated with BPA. The limit of determination using the developed method is 0.1 μg/kg, the linearity range of the calibration curve is 0.3–12 μg/kg (r2 = 0.994). As real samples for analysis, we used bottom sediments selected near the discharge of wastewater treatment plants in the city of Voronezh (Voronezh River and Don River). The BPA concentration in bottom sediments is 3.83–6.52 μg/kg. [ABSTRACT FROM AUTHOR]

The field-effect transistors (FETs) based on reduced graphene oxide (rGO) with SiO2, porous silicon (PS), and oxidized porous silicon (PSox) supporting layers were obtained. The influence of charged impurities in the silicon substrate and electrically active defects in the support layers on the electrical properties of the FETs was studied based on the capacitance-voltage characteristic analysis. Localized electron states in the SiO2, PS, and PSox supporting layers that affect the charge transfer in the rGO-based FETs were determined using thermally stimulated depolarization spectroscopy. The influence mechanisms of various supporting layers on the electrical characteristics of the obtained FETs are discussed. [ABSTRACT FROM AUTHOR]

As numerous communication devices use multiband electromagnetic waves in modern society, electromagnetic interference (EMI) shielding materials become increasingly important due to the harmful effects of electromagnetic waves. While metal-based materials have shown high shielding performance, they have many drawbacks such as high density, high processing cost, and low corrosion resistance. Conductive polymer composites (CPCs), which can overcome these shortcomings of metal-based materials, have become increasingly popular in recent years. In this study, non-oxidized graphene flakes (NOGFs) are synthesized by exfoliating the ternary graphite intercalant compound (t-GIC) and used as fillers for CPCs. The electrical conductivity and EMI shielding effiency (SE) of NOGF/polyvinylidene fluoride (PVDF), graphite/PVDF and reduced graphene oxide (rGO)/PVDF composites are investigated. NOGF/PVDF composites showed notably enhanced electrical conductivity and EMI SE than the others. This is mostly due to the non-oxidative fabrication method that does not destroy the sp2 structure of graphene sheet, thus preserving the unique electrical properties of graphene. [ABSTRACT FROM AUTHOR]

In this study, a compound filler consisting of zinc sulfide (ZnS) nanoparticles and reduced graphene oxide (RGO) was synthesized using the hydrothermal method and utilized to enhance the tribological properties of the polyimide (PI) film. The ZnS@RGO/PI composites displayed the lowest wear rate of 3.89 × 10−8 mm3 N−1 m−1 at a load of 200 N, which were significantly lower than that of both pure PI and RGO/PI films. Furthermore, the microstructure and chemical composition of the compound were characterized and analyzed, revealing that the ZnS nanoparticles were effectively attached to the surface of RGO through the chemical bonding between them. Finally, finite element analysis shows that the chemical bonding between ZnS and RGO have the effect to stop the crack expanding under pressure, and a wear mechanism is also given to demonstrate this 'Ball-on-plane' compound's enhancement to the tribological properties. [ABSTRACT FROM AUTHOR]

Here, a novel kind of composite scaffold was fabricated by loading vascular endothelial growth factor (VEGF) and gastrodin liposome (GAS-LP) into electrospun silk fibroin/graphene oxide(SF/GO)nanofibrous and silk fibroin sponge-filled, respectively. Our results demonstrated that VEGF and GAS exhibited different release patterns in vitro which VEGF showed rapid release rate in the first few days while GAS was released slowly and continuously as encapsulated in liposomes. The scaffolds realized the combination of intraneural vascularization drugs and electrical stimulation effectively, leading to enhanced growth of RSC96 cells. Furthermore, the scaffolds could protect RSC96 cells in an inflammatory environment. [ABSTRACT FROM AUTHOR]

The properties of graphene oxide–detonation nanodiamond composites obtained as a result of heterocoagulation of graphene oxide and hydrogenated detonation nanodiamonds in aqueous mixtures were studied. The resulting composites with different proportions of graphene oxide and detonation nanodiamond were subjected to drying and subsequent heat treatment in a vacuum, converting graphene oxide into graphene. The structure of the composites was studied using electron microscopy and Raman spectroscopy. The specific surface area and porosity of the obtained samples were studied by analyzing nitrogen adsorption isotherms. A model for the composite formation and a possible technology for producing a material based on it with different specific surface area values and pore structure are proposed. It is shown, that the largest possible specific surface area of two-component structures of the «DND/GO» type does not exceed 500 m2·g−1. It was also concluded that it is necessary to achieve a uniform distribution of detonation nanodiamond particles over the surface of graphene sheets. [ABSTRACT FROM AUTHOR]

The time-dependent graphene oxide (GO) reduction in medium vacuum under ultraviolet (UV) irradiation at 365 nm has been investigated. We found that GO exposed to UV at room temperature and at a vacuum of about 10−1 mbar shows a notable oxidation for irradiation times up to about 60 min followed by a successive reduction up to 210 min. Characterization measurements have been performed mainly using the Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FTIR) and Raman spectroscopies. ATR-FTIR spectra, acquired in the (400–4000) cm−1 wavenumber range, have indicated an initial decrement of the IR transmission (oxidation process) with the exposure time up to about 60 min and a successive increase of the IR transmission (reduction process) for greater irradiation times up to 210 min. The IR transmission bands are attributed to the oxygen functional groups contained in GO which increase for low UV exposure times and gradually disappear during the UV-induced reduction process. Raman spectra confirm this interpretation showing a decrease of the AD/AG ratio value, with respect to the GO virgin value, for low UV exposure times and an increase for greater times. The GO oxidation and reduction processes, due to the UV GO treatment in medium vacuum conditions, have been also verified by energy dispersive X-ray fluorescence and surface wettability measurements. [ABSTRACT FROM AUTHOR]

In this work, a particular type of carbon nano-material, like graphene oxide (GO), is synthesized in different batches by varying oxidation times, ranging from 1 to 4 days. The synthesis process initially starts with the oxidation of commercially available graphite powder and subsequently exfoliates the obtained graphite oxide in an aqueous solution using a high-frequency ultrasonication process. The synthesized GO batches were characterized using different characterization techniques to authenticate the formation of GO. The highly oxidized GO in an aqueous solution was selected and used as a strength-enhancing additive in concrete. The concrete mixes containing highly oxidized GO at the dosage of 0.01% 0.03%, 0.05%, 0.07%, and 0.09%bwoc were prepared to assess the strength and durability parameters. The GO (4 d) with 0.09%bwoc in concrete increases compressive strength by 58%, tensile strength by 41%, and flexural strength by 43% at 56 days. The results proved that the 0.09%bwoc GO dosage in cement concrete could effectively improve mechanical and durability performances compared to other mixes. Furthermore, the results are verified with the microstructural investigation using FE-SEM in secondary electron (SE) and backscattered electron (BSE) mode to monitor the microstructural changes and thickness of the interfacial transition zone (ITZ) during cement hydration. [ABSTRACT FROM AUTHOR]

This study aims to reveal the growth kinetics of ZnO nanoflakes and ZnO/GO nanocomposite films obtained at different Zn precursor salt concentrations by electrochemical deposition method and to evaluate the catalytic performances of the obtained films. The films were grown on FTO substrate with Zn precursor salt concentrations of 0.1 M, 0.125 M, and 0.175 M. Characterization of the obtained films was performed by XRD, SEM, UV–vis–NIR, Raman, and XPS analyses. The strong photocatalytic capabilities of the synthesized ZnO nanoflakes and ZnO/GO nanocomposite films were demonstrated by comparative analyses with the existing literature. Accordingly, photocatalytic experiments carried out under UVA irradiation revealed the high performance of the synthesized samples in the degradation of MB dye. The reaction kinetics were investigated using the Langmuir‐Hinshelwood kinetic model, resulting in high kobs values and R2 coefficients. ZnO nanoparticles showed a kobs of 0.038 min−1 and an R2 value of 0.96, while ZnO/GO nanocomposite films showed a kobs of 0.055 min−1 and an R2 value of 0.92. The significant increase in the degradation percentage shows the significant improvement achieved by the integration of GO, despite a slightly lower R2 value for the ZnO/GO nanocomposite film compared with ZnO nanoflakes films. [ABSTRACT FROM AUTHOR]

Nanocomposites, produced through mechanical blending, serve to enhance thermal performance of heat exchangers, solar collectors, and photovoltaic-thermal systems. This work employs an experimental methodology to assess the thermal charging (TC) and thermal discharging (TDC) of a composite generated by mixing graphene oxide (GO) and paraffin wax. TC and TDC of the GO-reinforced paraffin wax-based phase change material (PCM) have been examined across different flow rates (0.375, 0.75, and 1.5 L/min) and concentrations of GO (ranging from 0.25 to 1.00 vol%). The results exhibit a direct correlation between TC, TDC and efficiency, and reaction parameters (flow rate and volume concentration of GO). The experimental and predicted values of TCs, TDCs, and efficiencies fell ±15% (for TC and TDC), and ±9% for thermal efficiency, demonstrating a satisfactory level of agreement. This holds a practical application and valuable predictive tool for estimating TC, TDC, and thermal efficiency on known flow rates and concentrations of GO in wax-based PCMs. [ABSTRACT FROM AUTHOR]

Polydimethylsiloxane has the characteristics of low-temperature flexibility and excellent aging resistance. However, high molecule mobility and weak interactions between PDMS molecules result in poor mechanical strength and deficient gas barrier properties of PDMS composites. Herein, diamino-polydimethylsiloxane (PDMS) was reacted with 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) to form urea-carbamate functionalized PDMS (MDI-PDMS-BDO) with different hard segment contents. Furthermore, the modified graphene oxide (iGO) was obtained by the reaction between graphene oxide (GO) and MDI. iGO was further introduced into the functionalized PDMS to prepare iGO/urethane-urea functionalized PDMS composites (iGO/MDI-PDMS-BDO). An ordered structure was formed by the hard segments of the MDI-PDMS-BDO functionalized PDMS. A strong urea-based interface was also obtained between iGO and functionalized PDMS. iGO became the cross-linking center in the iGO/MDI-PDMS-BDO composites. Due to the ordered structure of hard segments and the iGO network formed in the PDMS composite with only 0.07 wt% iGO, the tensile strength and gas barrier properties of the iGO/MDI-PDMS-BDO composite were increased by 18 times and 64.27%, respectively, compared with pure PDMS. [ABSTRACT FROM AUTHOR]

The applicability of two layered double hydroxide adsorbents, that is, Zn/Al LDH and the reduced graphene oxide-modified Zn/Al-rGO LDH for the solid phase extraction-preconcentration of naproxen followed by HPLC determination is evaluated and compared. The adsorbents are characterized by using XRD, FT-IR, FE-SEM, BET, and TEM techniques. The optimization of parameters affecting the extraction procedure included pH and sample solution volume, amount of the adsorbents, adsorbent/sample solution contact time, type, concentration, and volume of the desorption solution, and the time required for desorption process was performed by using univariate method. It is assumed that the uptake of anionic form of naproxen is taken place via the ion exchange mechanism with interlayer carbonate anions of the studied LDHs. The applicability of the adsorbents is evaluated by the determination of naproxen in human urine, hospital, and pharmaceutical wastewater samples. The obtained linear ranges by employing the unmodified and modified LDHs for the determination of naproxen in pharmaceutical wastewater were found to be 10–530 µg L−1 (R2 = 0.9999) and 5–630 µg L−1 (R2 = 0.9999), respectively. The limits of detection and enrichment factor were appraised as 5.1 µg L−1 and 42 by employing Zn/Al LDH, and 3.1 µg L−1 and 54.5 by using Zn/Al-rGO LDH. Both investigated LDHs are able to be used in solid phase extraction-preconcentration of naproxen in real samples. However, the evaluated figures of merit reveal that the modified Zn/Al-rGO LDH is more efficient adsorbent than the unmodified Zn/Al LDH for the extraction of naproxen. [ABSTRACT FROM AUTHOR]

Environmental pollution significantly challenges human health, ecosystems, and the planet's sustainability. Widespread air, water, and soil contamination from various pollutants requires effective and sustainable solutions to reduce or eliminate pollution and its impacts. In this work, we designed novel magnesium oxide and graphene oxide (MgO@GO) composite free-standing membranes for nanofiltration. The membranes were characterized with the help of Fourier-transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Further, free-standing MgO@GO composite membranes with different thicknesses were used to measure the water permeance. 410 nm-thick membranes showed high water permeance up to 480 ± 5 Lm−2 h−1 bar−1. Further, the rejection efficiency of the membrane was measured against NaCl, CaCl2, Pb(NO3)2, CdCl2, and amoxicillin. The MgO@GO membrane (410 ± 10 nm) showed 100% rejection for amoxicillin and 99% for Pb(NO3)2, respectively. Additionally, the membranes were stable under acidic and neutral conditions for approximately ∼80 days and may used on an industrial scale to ensure water is clean and free from harmful substances. [ABSTRACT FROM AUTHOR]

Designing scaffolds to fit with essential requirements for wound dressings is still a challenge. A material with high antibacterial activity and biocompatibility is targeted. In this case, the electrospinning technique is used to fabricate a nanofiber scaffold of polylactic acid (PLA) embedded with ginger and/or molybdenum trioxide (MoO3) and cupric oxide (CuO). The nanofiber scaffolds were examined using SEM, TEM, Raman, XRD, FTIR, and EDX. In addition, the surface topography of the nanofiber scaffold of MoO3/ginger@PLA showed that the nanofiber diameters differ from 0.085 to 0.34 µm. Furthermore, the contact angle of the water drop on the surface of the pure PLA and MoO3/CuO/GO/ginger@PLA is remarkably changed from 32.3° to 18.9°. Moreover, the cell viability test of the composition MoO3/CuO/GO/ginger@PLA is above the IC50 at all concentrations. Meanwhile, the antibacterial test exhibited antibacterial activity against E. coli and S. aureus for the scaffolds, with an inhibition zone of 23 ± 0.816 mm and 16.33 ± 0.942 mm for MoO3/CuO/ginger@PLA and 20.3 ± 0.471 mm and 15.33 ± 0.943 mm for MoO3/CuO/GO/ginger@PLA. The obtained results are appropriate to aid the cells to grow and proliferate. As a result of that, the fabricated scaffolds could be utilized in biomedical applications. [ABSTRACT FROM AUTHOR]

Antibacterial dressings play an important role in wound management, especially in chronic wounds. Due to the excellent water retention, antibacterial hydrogel has become an ideal wound dressing. In this paper, the effective antibacterial dressing was constructed with the poly N-isopropylacrylamide (PNIPAM) hydrogel and graphene oxide loading nanosilver particles (GO-Ag) by the in situ chemical crosslinking method. The molecular structure, viscosity and mechanical properties, antibacterial agent content, antibacterial performance, temperature-sensitive antibacterial relationship and biocompatibility of PNIPAM-based GO-Ag composite hydrogel (PNIPAM/GO-Ag) were systematically characterized by the scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), plate counting and other methods. The results showed that the introduction of GO-Ag increased the pore structure of PNIPAM/GO-Ag hydrogel and provided more active sites for the release of silver nanoparticles, wherein the content of nanosilver in PNIPAM/GO-Ag hydrogel was only 0.01%, meeting the requirements of application as antibacterial dressings. Moreover, when the hydrogel was subjected to heat contraction, silver nanoparticles could release more quickly and efficiently. The antibacterial rates of the PNIPAM/GO-Ag hydrogel against E. coli and S. aureus were 99.8 and 99% at 37 °C, respectively, higher than those at 25 °C (92, 95%). Compared with the pure PNIPAM hydrogel (1423.0%), the swelling rate of PNIPAM/GO-Ag hydrogel could reach 2024.6%, certifying its ability to absorb exudate of wound site. When the deformation was less than 80%, the hydrogel could maintain excellent elastic deformation recovery ability, and the viscosity of hydrogel at human body temperature was 38 Pa·s. These prove that it had a good fit with the skin, could dissipate more energy and restore shape. The hemolysis rate of PNIPAM/GO-Ag hydrogel was less than 5%, showing good bio-safety. These all demonstrated the PNIPAM/GO-Ag hydrogel can be used as a potential application for the skin wound dressing. [ABSTRACT FROM AUTHOR]

The adsorption of weighty metal particles from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Heavy metal ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, design ability, and stability have been proposed. In this review, a carbon-based adsorbent, named M-NC, and graphene oxide were created for the particular evacuation of weighty metal particles. To increase the potential for Heavy Metals (HM) immobilization, sulfide-modified biochar was created via a process called synchronous carbon layer epitome. A hypothetical physicochemical and thermodynamic examination of the adsorption of weighty metals Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was done with factual material science fundaments. The biochar with large surface areas is utilized to eliminate weighty metal particles, quite possibly the most significant heavy metal pollutants, from aqueous solutions. The limit of the adsorbent for eliminating weighty metal ions was concentrated on utilizing Langmuir adsorption isotherm under ultrasound-helped conditions. The Mesoporous Silica Nanoparticles (MNCs) can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous measurable physical science adsorption typically was utilized to describe and analyze the experimental heavy metal removal isotherms at 30°C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The experimental results were investigated in terms of Langmuir and pseudo-2nd-order kinetic equations, Freundlich and isotherm models. The outcome of pH, initial heavy metal ion concentration, contact time, and adsorbent dosage regarding the adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the hydrogel was examined. This study contributes to the advancement of information in the ground of environmentally friendly heavy metal removal techniques, specifically focusing on the usage of biomass-based adsorbents. These findings have the potential to address the need for effective solutions in water purification and environmental cleanup efforts. [ABSTRACT FROM AUTHOR]

In the engineering context of island blowing and reclamation, the modification effect of graphene oxide on the mechanical properties of calcareous sand cement mortar is analyzed, and the modification mechanism is elaborated from the microscopic perspective. The experimental results show that graphene oxide promotes the hydration reaction of calcareous sand-cement mortar, and the amount of graphene oxide doping significantly affects the modification effect. The modification effect gradually enhances when the graphene oxide doping amount increases from 0 to 0.06%, and the unconfined compressive strength of the specimens increases up to 36.96%. However, the modification effect decreases when the doping amount is 0.1% compared with that of 0.06%. The results of scanning electron micrographs and energy dispersive spectrometer tests indicate that the addition of graphene oxide accelerates the agglomeration of C-S-H gel produced by the reaction of calcareous sand cement mortar, forming a dense mesh-like structure, which enhances the unconfined compressive strength of the specimens. The oxygen-containing functional groups in graphene oxide are interlinked with the free Ca2+ in the hydration products, eventually producing crystals with the chemical formula (3CaO·Al2O3·CaSO4·12H2O). The generation of crystals leads to the reduction of pores inside the cement mortar and improves the specimen's compression strength. [ABSTRACT FROM AUTHOR]

[Display omitted] • A microorganism template strategy is used to construct cobalt-phosphide-graphene. • This designed catalyst has comparable HER performance in acidic electrolyte. • The charge redistribution between Co 2 P and pyrrole-N interprets boosted activity. Developing highly efficient and sustainable hydrogen evolution reaction (HER) electrocatalysts is important for the practical application of emerging energy technologies. The spherical structure and phosphorus-rich properties of Chlorella can facilitate the construction of comparable transition metal phosphide electrocatalysts. Here, a microorganism template strategy is proposed to construct a cobalt-phosphide-graphene hybrid. Chlorella can absorb metal ions, and the generated rough spherical nanoparticles are uniformly distributed around the reduced graphene oxide nanosheets. This designed catalyst has comparable HER performance in acidic electrolytes and needs an overpotential of only 153 mV at a current density of 10 mA cm−2. The experimental and density functional theory results imply that the charge redistribution between Co 2 P and pyrrole-N is the key factor in enhancing the HER activity. The induced electron aggregation at the N and P sites can serve as a key active site for absorbing the adsorbed hydrogen atom intermediate to accelerate the HER process, contributing to the active sites of Co 2 P- and pyrrole- N -doped carbon with 0 eV hydrogen adsorption free energy. This work provides a broad idea for synthesizing advanced catalysts by a biological template approach, facilitating the innovative integration of biology and emerging electrochemical energy technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] Nanoscale graphene-semiconductor composite photocatalysts with fascinating properties in the photocatalytic hydrogen evolution have inspired numerous interests in broad research fields. The architectures with efficient light response and promoting charge separation at the interface between reduced graphene oxide (RGO) and semiconductor are critical, yet synthesizing them remains a formidable challenge. Herein, the photodiode array-like LaNiO 3 /N,P-RGO (LNO/N,P-RGO) nanoreactor was constructed using an innovative strategy of acid etching-induced nanocutting self-assembly. Ammonium dihydrogen phosphate working as both a nitrogen phosphorus co-dopant and an acid etching reagent, cuts perovskite LaNiO 3 (LNO) nanoparticles into nanorods, which are bonded evenly on the nitrogen phosphorus co-doped reduced graphene oxide (N,P-RGO) to form an n-n semiconductor heterojunction LNO/N,P-RGO as a photodiode array-like nanoreactor via hydrothermal treatment. The photodiode array-like nanostructure exposes more active sites that are conducive to light absorption. The robust Ni-C and P-O bonds promote the narrowing of space-charge region at the interface by UV irradiation, thereby improving the transport of photogenerated carriers by visible light irradiation. The LNO/N,P-RGO nanoreactor exhibits excellent photocatalytic hydrogen evolution performance with a yield of up to 354 μmol g−1 h−1 under UV–visible light, which is 50 times higher than that of pure perovskite LNO, and it also displays favorable recycling stability. [ABSTRACT FROM AUTHOR]

The rapid reduction of fossil fuels due to excessive consumption has prompted the development of sustainable energy conversion systems, leading to an increasing energy crisis and environmental concerns. The continuous energy demand motivates researchers to explore new options for energy conversion and water splitting. But, the fabrication of electrocatalysts with low overpotential for water splitting is challenging task. Current study reports the fabrication of rGO-based Dy 2 O 3 composite as an electrocatalyst for water splitting. The rGO-based Dy 2 O 3 was fabricated via a hydrothermal approach. The various physical methods were performed to assess the morphological, vibrational, structural, functional and textual characteristics of synthesized electrocatalysts. In addition, the electrochemical potential of generated materials is evaluated in 1 M KOH electrolyte using Ni foam (NF) serving as conductive material. The electrochemical findings show that rGO-based Dy 2 O 3 composite exhibits a least overpotential of 251 mV at current density (C d) of 10 mA cm−2 and possessing Tafel slope (36 mV dec−1). The Dy 2 O 3 /rGO composite demonstrates stability over a period of 50 h with a minute change in current. The Dy 2 O 3 /rGO composite stands out as a favorable catalyst for OER and future energy conversion applications due to its remarkable electrochemical characteristics. [ABSTRACT FROM AUTHOR]

Synergistic modification strategy of graphene and mullite was used to introduce mullite and graphene into C/C–SiC–ZrC composites by chemical liquid-vapor deposition to improve ablation resistance. The ablation resistance and behaviors were comparatively studied under a heat flux of 2.38 MW/m2 for 100 s. Results showed that the appropriate content mullite modified C/C–SiC–ZrC composites has better ablation resistance due to the sufficient SiO 2 , Al 2 O 3 , and ZrSiO 4 as healing agents and oxygen barrier and the synergistic effect with ZrO 2 to form a denser and more stable oxide layer with the mass and linear ablation rates of 0.69 mg/s and −0.93 μm/s, respectively. The introduction of graphene improves the heat-force distribution, and as a high heat transfer medium and reinforcing phase, reduces the thermal concentration, cracking, and spalling of the oxide layer and further improves the ablation resistance, with mass ablation rate and linear ablation rate of −0.34 mg/s and −0.89 μm/s, respectively. [ABSTRACT FROM AUTHOR]

The CoCrFeMnNi high entropy alloy (Cantor), and its variant incorporating 0.2 wt% reduced graphene oxide (rGO), denoted as Cantor + rGO, were successfully synthesized using mechanical alloying followed by spark plasma sintering. Comprehensive characterization utilizing FESEM, XRD, and TEM provided detailed insights into the microstructural features of the materials. The addition of rGO reduced crystallite size from 209 nm to 169 nm, promoted a uniform distribution of carbide phases of smaller size, and enhanced microhardness from 421.8 HV to 510 HV for Cantor and Cantor + rGO, respectively. The incorporation of rGO into the Cantor structure led to an increase in compressive yield strength (CYS) from 1100 MPa for Cantor to 1250 MPa for Cantor + rGO sample. A significant decrease in corrosion current density of samples from 6.1 ± 1.5 μA/cm2 for Cantor to 1.4 ± 0.9 μA/cm2 for Cantor + rGO was observed due to the addition of rGO reinforcement. Moreover, the pitting corrosion resistance was increased in rGO-reinforced Cantor, as revealed by cyclic polarization test. This research underscores the potential for utilizing rGO as a reinforcing agent to optimize the mechanical and corrosion resistance characteristics of HEAs, offering promising avenues for advanced materials in diverse applications. [ABSTRACT FROM AUTHOR]

In this research study, various nanocomposites, namely Dy 2 O 3 , Sm 2 O 3 , HAP/Dy 2 O 3 , HAP/Dy 2 O 3 /GO, and HAP/Sm 2 O 3 /GO, were extensively examined and analyzed. The primary focus was on the development of advanced biomaterials with improved mechanical properties, biocompatibility, and antimicrobial activity. The investigation involved the use of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques to observe the distinctive nanorods of hydroxyapatite (HAP) within the ternary nanocomposite. The SEM micrographs yielded an average size of 69 ± 22 * 19 ± 4 nm for the HAP nanorods, accompanied by an average roughness measurement of 10.5 nm. The TEM analysis provided further insights into the distribution of HAP and Sm 2 O 3 within graphene oxide (GO) nanosheets, revealing HAP particles measuring 20 nm in size and 65 nm in length, and Sm 2 O 3 particles measuring 6 nm in size. To evaluate the biocompatibility of the newly developed ternary nanocomposite, HAP/Dy 2 O 3 /GO, osteoblast cells were employed. The results showed a minor decrease in cell viability, with a measured percentage of cell viability at 97.5 ± 2.1 %. Furthermore, the HAP/Dy 2 O 3 /GO nanocomposite exhibited notable antibacterial properties against E. coli and S. aureus bacteria, as indicated by inhibition zones measuring 15.3 ± 0.8 mm and 15.9 ± 1.1 mm, respectively. The unique composition of HAP/Dy 2 O 3 /GO demonstrated enhanced roughness parameters and improved biocompatibility due to its altered topological features. Additionally, its remarkable antibacterial activity and robust mechanical strength establish HAP/Dy 2 O 3 /GO as a promising candidate for further investigation as a biomaterial for bone implants. [ABSTRACT FROM AUTHOR]

Multi-layered graphene and graphene oxide have been used as reinforcements in nanodevices and nanocomposites due to their extraordinary mechanical and thermal properties. However, compared to graphene, graphene oxide has a lower Young's modulus and lower thermal conductivity. Nanodevices and nanocomposites based on multi-layered graphene and graphene oxide require different mechanical properties and thermal conductivity. This study employed molecular dynamics simulation to investigate 10 models of multi-layered graphene and graphene oxide (in the form of different layer arrangements) in single, double, and triple layers. The results showed that an increase in the number of graphene oxide layers leads to irregularities in the nanosheets, resulting in decreased thermal conductivity (by 64.4%) of the nanosheets decreases. Furthermore, the greater number of graphene layers in multi-layer nanosheets resulted in an increase in Young's modulus (by 79.3%) and tensile strength (by 73.7%). Moreover, the arrangement of graphene and graphene oxide is a crucial factor that can significantly impact the mechanical properties and thermal conductivity of the models. Moreover, an increase in temperature can lead to a decrease in Young's modulus of multilayered nanosheets. Increasing the number and size of graphene layers enhances both the ultimate tensile strength and the critical energy release rate. [ABSTRACT FROM AUTHOR]

Ternary nanocomposites of reduced graphene oxide/multi-walled carbon nanotubes/cobalt oxide nanoparticles (rGO/MWCNT/Co3O4) were synthesized employing a facile hydrolysis method with subsequent heat treatment. The good electrical conductivity and remarkable carrier mobility of rGO and MWCNTs make them a suitable matrix for hybrid supercapacitors, and their composites with metal oxides exhibit enhanced electrochemical properties due to the advantages of the synergistic contribution and the integration of different dimensionalities. The binary counterparts of Co3O4 with GO or MWCNTs were also produced using the same technique to gain additional insight into the characteristics of the individual components. The structural and morphological properties of the composites were analyzed using various analytical techniques. The electrochemical behaviors of the prepared composites were investigated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 M H2SO4. A platinum electrode modified with the rGO/MWCNT/Co3O4 composite displayed a remarkable specific capacitance of 922 F g−1 at a current density of 1 A g−1 composite with a negligible capacitance drop after 2000 cycles. The symmetric supercapacitor fabricated using the rGO/MWCNT/Co3O4 composite showed an energy density of 32.2 Wh Kg−1 at 1 A g−1, and the corresponding power density was 2000 W Kg−1. The supercapacitor fabricated using the composite displayed 83% capacitance retention after 2000 cycles at 3 A g−1 composite. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a potential material for application as nano-reinforcements in cementitious composites owing to its high-water dispersibility, aspect ratio and outstanding mechanical characteristics. In this study, the combined effect of GO and fly ash on strength properties, stress–strain behaviour and static modulus of elasticity of high-strength concrete was investigated. In addition, microstructure has been characterized using SEM and EDS techniques. The addition of GO at 0.15% and the replacement of cement with fly ash at 10, 20 and 30% by weight was considered. The results exhibited that the addition of GO at 0.15% improved the compressive and flexural strength of concrete by 24.3 and 25.2%, respectively, at 7 days. The combined effect of GO and fly ash on the strength properties of concrete at 7 days was greater than control concrete demonstrating that GO can offset the effect of fly ash on delaying the strength growth at an early age. From the experimental results, it can be concluded that the addition of GO and fly ash into the concrete improved both the strength and elastic modulus, consequently exhibiting positive synergy in hybridizing GO and fly ash into the concrete. Also, the microstructure properties indicated that the GO and fly ash-based concrete mixes exhibited a denser microstructure. Furthermore, a nonlinear numerical model was also created for GO and fly ash-based concrete with finite element-based software ATENA-GiD to validate the experimental findings. The nonlinear numerical model successfully predicted the behaviour under monotonic axial compression and was quite beneficial in minimizing the tedious experimental testing. Finally, it is found that the findings of both the experimental and numerical investigations are in good agreement. [ABSTRACT FROM AUTHOR]

Graphene has intriguing electrical, mechanical, thermal and biological properties that are being investigated for use in composites, modern electronics, membranes, and in the industry. Also, graphene has huge biological applications. Hydroxypropyl methylcellulose (HPMC) is a widely used bio-polymer effective for various biomedical applications. As a filler in this polymer matrix, graphene oxide (GO), reduced graphene oxide (RGO) and silver (Ag) nanoparticles (NPs) can be used to improve various properties of the matrix. They are also beneficial for bio-applications like drug delivery, the production of reactive oxygen species (ROS) and the antimicrobial properties of nanocomposite films. Here we synthesize a series of polymer nanocomposites taking GO, RGO and Ag NPs as a filler by the solution mixing method and explore the comparative biological application of such composites. We choose Ag NPs as it has the superior potential for multiple drug resistance. X-ray diffraction, Fourier-transform infrared and scanning electron microscope studies are used to describe how nanocomposites are formed. Energy-dispersive X-ray and dynamic mechanical analyzer analyses were also done to check elemental percentage in nanocomposite films and mechanical properties, respectively. To check several fruitful applications, antimicrobial properties, ROS generation and in-vitro drug release study of nanocomposite films with the loading of Ketorolac Tromethamine were also performed. [ABSTRACT FROM AUTHOR]

This study presents the development of an electrochemical immunosensor based on a nanocomposite of nitrogen-doped reduced graphene oxide (N-rGO) and copper oxide (CuO) for the detection of erythropoietin (EPO). The sensor demonstrated remarkable stability, repeatability, and biocompatibility, with a linear detection range of 10-2 ng/L to 104 ng/L and a detection limit of 3 pg/L. The sensor exhibited a relative standard deviation of less than 4.4 % for five electrodes detecting 1.0 ng/L EPO, indicating excellent repeatability. The sensor maintained a stable electrochemical current response with less than 3.9 % change after 30 days, demonstrating its long-term stability. The sensor's performance was validated using human serum samples, showing EPO recovery rates ranging from 90.00 % to 98.00 %. These findings suggest that the immunosensor is suitable for clinical applications, contributing to advancements in bioanalytical monitoring and the detection of performance-enhancing drugs. [ABSTRACT FROM AUTHOR]

The development of a precise and sensitive electrochemical sensor is essential in the field of medical diagnostics in order to identify gemcitabine, a chemotherapy drug that is commonly used to treat breast cancer. This work presents a novel electrochemical sensor based on a reduced graphene oxide (rGO) nanocomposite and a zirconium-based metal-organic framework (Zr-MOF) with terephthalic acid as a ligand. Gemcitabine (GEM), a chemotherapy medication used to treat breast cancer, is detected with remarkable sensitivity and selectivity by the Zr-MOF-rGO modified graphene paste electrode (GrPE) sensor. By combining the strong structure and active sites of Zr-MOF with the large surface area and electrical conductivity of rGO, the sensor's design maximizes electron transfer rates and GEM adsorption capacity. The sensor outperforms current GEM sensors with its wide linear detection range (0.5–490 μM) and low detection limit (0.008 μM). The sensor's long-term analytical applicability is confirmed by stability and reusability studies, which produced accuracy rates surpassing 94 % and RSD values below 4.21 % in recovery trials using spiked human blood serum and urine samples. Overall, the results of this investigation show that the Zr-MOF-rGO/GrPE electrode has the potential to be a useful platform for the detection of gemcitabine in patients with breast cancer. [ABSTRACT FROM AUTHOR]

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This study provides and investigates the fabrication of graphene oxide (GO) sheets decorated with chitosan nanoparticles (CSNP) through the hybridizing of GO and CS, by the addition of tetraethyl orthosilicate (TEOS) as a cross-linker agent. The fabricated GO-CSNP composite was characterized using several advanced techniques. Furthermore, various parameters affect the sorption of Sr(II), such as contact time, pH, initial concentration, dosage, temperature, and coexisting ions. The experimental results were in accordance with the pseudo-second-order reaction. The interaction mechanism between Sr(II) and GO-CSNP composite was accurately described by the Langmuir isotherm model with a maximum adsorption capacity of 473.93 mg/g. The GO-CSNP composite demonstrated exceptional selectivity for the sorption of Sr(II) over Y(III) at a high concentration ratio of 10:1 for Sr2+ to Y3+, respectively. Furthermore, the GO-CSNP adsorbent demonstrated considerable potential as a highly effective sorbent for the adsorption of Sr(II), Mo(VI), Cd(II), and Cs(I) ions. The results revealed that the prepared composite was effectively capable of removing various fission products. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) consists of many functional groups containing oxygen that helps in its chemical modifications. Thus, we have explored the synthesis, and corrosion inhibition application of n-butylamine (nBA) functionalized GO, i.e., GO-nBA for N80 steel in the acidizing environment (15 % HCl). NMR and TEM characterized the GO-nBA. The performance of GO-nBA was evaluated via chemical and electrochemicals methods that are supported by surface examination techniques. The PDP results supports the mixed nature of protection ability of GO-nBA. Additionally, the excellency of GO-nBA is confirmed by the value of 93.93 % efficiency. The surface study furthermore represents smooth texture with the addition of GO-nBA. The computational analysis reveals excellent inhibitive performance of GO-nBA. [ABSTRACT FROM AUTHOR]

A novel graphene-modified molecularly imprinted polymer-based electrochemical sensor (MIP/RGO-GCE) was developed for the sensitive and selective detection of sibutramine in sports doping control. The sensor was fabricated by electropolymerizing o-phenylenediamine on a reduced graphene oxide-modified glassy carbon electrode in the presence of sibutramine as the template molecule. Under optimized conditions, the MIP/RGO-GCE sensor exhibited a wide linear range (0.05 to 20 μM), low detection limit (0.02 μM), high sensitivity (1.27 μA/μM), good precision (RSD < 2.7%), and long-term stability (93.5% retention after two weeks). The sensor's applicability was successfully demonstrated by analyzing spiked human urine and serum samples, with recoveries ranging from 95.8 to 103.2% and good agreement with the reference HPLC method. Furthermore, the sensor showed a rapid response time of 5 s and excellent reproducibility with an RSD of 1.5% for repeated measurements. The proposed sensor offers a rapid, cost-effective, and reliable alternative to traditional chromatographic methods for sibutramine detection in sports doping control. [ABSTRACT FROM AUTHOR]

This work reports on the synthesis of a unique nickel oxide/carboxylated reduced graphene oxide (NiO/c-rGO) nanocomposites electrochemical sensor for the detection of quercetin (QCT). The successful integration of NiO nanoparticles into the c-rGO matrix was confirmed by the characterization and synthesis of both the NiO nanoparticles and c-rGO. After that, the glassy carbon electrode (GCE) was treated with the NiO/c-rGO nanocomposite, which produced a modified GCE with improved electrochemical characteristics. The NiO/c-rGO modified GCE showed a wide linear-range of 0.5 to 750 µM and a low detection limit of 0.016 µM, indicating high sensitivity towards QCT. Additionally, the sensor exhibited excellent selectivity, with very little interference from examined kinds of analytes, both organic and inorganic. Additionally, the sensor's long-term stability was demonstrated by its steady redox reaction to QCT, with a sensitivity of roughly 96.68% over a 33-day period. The suggested sensor's use was evaluated by measuring differential pulse voltammetry on real samples, including onions, apple juice, honey, and green tea. These samples' QCT recovery rates, which varied from 96.00 to 99.40%, showed the precision, dependability, and potency of the suggested sensor. Based on these results, the NiO/c-rGO nanocomposite may be a great material to use in the creation of stable, highly sensitive, and selective electrochemical sensors for QCT detection. The food, pharmaceutical, and clinical diagnostics industries might all benefit greatly from this. This work enhances the field of electrochemical sensor technology and paves the way for the development of further sensors using similar nanocomposites. [ABSTRACT FROM AUTHOR]

Cryoinjury mitigation is key in cell cryopreservation. Here, we aimed to assess the effectiveness of nanographene oxide (nano-GO) for improving cryoprotectant agents (CPAs) in human adipose stem cell (hADSC) cryopreservation. For in vitro experiments, nano-GO (5 μg/mL) was added to the CPAs in the control, and passage (P) 2 hADSCs were collected and cryopreserved for around two weeks. We compared cytotoxicity, cell viability, immunophenotypes, proliferation, cell apoptosis, and tri-lineage differentiation. In vivo, studies used lipoaspirate to create non-enriched or hADSC-enriched fat tissues by combining it with PBS or hADSCs cryopreserved with the aforementioned CPAs. Each nude mouse received a 0.3 mL subcutaneous injection of the graft. At 12 weeks, the grafts were harvested. Histology, adipocyte-associated genes and protein, vascular density and angiogenic cytokines, macrophage infiltration, and inflammatory cytokines were analyzed. Nano-GO CPA contributed to increased cell viability, improved cell recovery, and lowered levels of early apoptosis. Nano GO at concentrations of 0.01–100 μg/mL caused no cytotoxicity to hADSCs. The absence of nano GOs in the intracellular compartments of the cells was confirmed by transmission electron microscopy. The fat grafts from the CPA-GO group showed more viable adipocytes and significantly increased angiogenesis compared to the PBS and CPA-C groups. Adding hADSCs from the CPA-GO group to the graft reduced macrophage infiltration and MCP-1 expression. Nano-GO plays an anti-apoptotic role in the cryopreservation of hADSCs, which could improve the survival of transplanted fat tissues, possibly via improved angiogenesis and lower inflammatory response in the transplanted adipose tissue. [ABSTRACT FROM AUTHOR]

This research endeavors to comprehensively explore the sorption dynamics of dyes from aqueous solutions utilizing a graphene oxide‐chitin (GO‐chitin) biosorbent. The investigation systematically evaluates the influence of key parameters, including temperature, pH, duration of contact, and initial dye doses, on the sorption efficiency of the biosorbent. Results obtained indicated that at acidic pH range, the dye removal efficacy was more than 80% for methyl orange and Remazol Brilliant Blue. Maximum removal efficacy was achieved within the 30 min of adsorption studies. Notably, the study underscores the remarkable adsorption capacity of GO‐chitin, varies in the range of 75% and 95%, for all three dyes, positioning it as a highly promising material for the remediation of polluted aquatic environments. The adsorption follows pseudo‐second‐order kinetics and Freundlich isotherm. These findings contribute valuable insights into the potential application of GO‐chitin as an effective biosorbent in the context of wastewater treatment, emphasizing its role in addressing environmental challenges associated with dye contamination in aqueous systems. [ABSTRACT FROM AUTHOR]

Nano-biocomposite hydrogel samples were produced using graphene oxide (GO) and agar and applied as adsorbents of organic components in water. The hydrogels were prepared by varying the wt% of Agar and GO. The samples were characterized, and batch adsorption experiments evaluated the effect of initial pH, equilibrium isotherms, and kinetics for the adsorption of the anionic dye Acid Orange 7 (AO) and the cationic dyes Nile Blue A (NB) and methylene blue (MB) in an aqueous medium. Overall, both hydrogel samples exhibited satisfactory results for removing NB and MB; however, there was no effective removal for the anionic dye AO. Adsorption equilibrium isotherms were obtained, and Freundlich, Langmuir, and Sips models were fitted to the experimental equilibrium data; moreover, kinetic data were adjusted to driving force models and particle mass balance. The maximum experimental adsorption capacities, 141.48 mg·g−1 (MB) and 284.69 mg·g−1 (NB), were obtained, on a dry basis, for the sample produced with 70 wt% of agar and 30 wt% of GO. Both hydrogels exhibited remarkable regenerative potential for NB and MB, with the adsorption capacity remaining constant, even after five adsorption/desorption cycles. [ABSTRACT FROM AUTHOR]

Shear thickening fluids (STF) represent stabilized and concentrated colloidal suspensions, wherein hard nanoparticles are dispersed within a liquid medium (polymer). Under the influence of impact forces, they exhibit non-Newtonian behavior, effectively dissipating energy through shear thickening. The optimization of the dispersion medium's viscosity is critical, as it not only fosters shear thickening but also facilitates proper particle dispersion. This study investigates the impact of graphene oxide (GO) as an additive in STFs, analyzing both static and dynamic rheological properties. STFs were formulated using colloidal silica particles (600 nm) and polyethylene glycol (PEG-200), with varied concentrations of GO particles (0.12–0.5 % w/W). The systems underwent comprehensive analysis concerning steady-state and dynamic-state rheological behavior under diverse conditions. The findings reveal that the inclusion of GO augments both static and dynamic rheological properties, reaching an apex at an optimal concentration of 0.36 % w/W. GO functions as a network builder within the STF, interacting with the existing particle network to create a more robust and interconnected structure. These enhanced properties underscore the potential of the synthesized STF for applications requiring impact resistance. [ABSTRACT FROM AUTHOR]

In this study, the composite materials based on the incorporation of diatomite of graphene oxide (GO)/reduced graphene oxide (rGO/diatomite) were developed and characterized by different techniques (SEM, XRD, FTIR and BET). Developed composites were used for the first time in the removal of uranium ions from aqueous solutions. In adsorption studies, parameters affecting the adsorption efficiency such as solution pH, temperature, contact time and initial U(VI) concentration were investigated using full factorial experimental design (FFED). ANOVA (analysis of variance) analysis within the 95 % confidence interval of the model applied to control the compatibility of the model and the experimental findings was examined. Langmuir, Freundlich and Temkin isotherms were used to determine the adsorption model and related parameters were calculated. In addition, adsorption thermodynamic parameters such as enthalpy, Gibbs free energy change and entropy were calculated. The uranium removal behaviour on GO/diatomite and rGO/diatomite was better characterized by the pseudo-second order and Langmuir models, indicating that uranium ions were chemically adsorbed onto composite materials. Additionally, it was observed that higher temperatures promoted the uranium removal on GO/diatomite and rGO/diatomite, suggesting that the removal process was a spontaneous endothermic and exothermic reaction, respectively. In addition, the adsorption of U(VI) with GO/diatomite and rGO/diatomite was investigated using density functional theory (DFT) study. Configuration and adsorption energy were determined. The GO/diatomite composite materials can be a promising candidate as an adsorbent for the removal of uranium from aqueous solutions. [ABSTRACT FROM AUTHOR]

Aerogel-based composites hold promising application prospects as potential electromagnetic wave (EMW) absorption materials, yet the construction of such materials with ingenious microstructures, appropriate magnetic/dielectric multi-components, and integrated multifunctionality remains considerably challenging. Herein, a multicomponent Co/MnO/Ti3C2Tx MXene/rGO (CMMG) hybrid aerogel featured with three-dimensional (3D) vertical directional channel architecture is reported. Benefiting from the synergistic effect arising from the 3D conductive networking structure, diverse heterogeneous interfaces, magnetic/dielectric multicomponent, and multiple loss pathways, the optimized CMMG-2 aerogel delivers fascinating EMW absorption capabilities, characterized by a minimal reflection loss (RLmin) of −77.41 dB and an effective absorption bandwidth (EAB) of 6.56 GHz. Additionally, the remarkable hydrophobicity, exceptional thermal insulation capabilities, and outstanding photothermal properties of CMMG-2 aerogel make it highly promising for multiple application in diverse and demanding environments. Interestingly, the distinctive pore structure of hybrid aerogel also allows it for sensitive and reliable detection of electrical signals caused by pressure changes and human motion. Thus, this research provides a viable design strategy for the development of lightweight, efficient, and multifunctional aerogel-based EMW absorption materials for various application scenarios. [ABSTRACT FROM AUTHOR]

This study was conducted to generate and investigate the structural characteristics and antioxidant properties of a nano-composite film produced from Vicia ervilia protein (VEPI)—Launaea acanthodes gum (LAG). The film containing Silybum marianum extract microcapsules (SMEM) at varying volumes (0, 2.2, 7.5, 12.8, 15 v/v) along with different concentrations of graphene oxide nanoparticles (GONPs) (0, 0.6, 2.0, 3.4, 4.0 w/v). The thickness, solubility, and moisture content of the film samples increased after the integration of SMEM and GONPs (P < 0.05). Fourier-transform infrared analysis of the film sample based on VEPI/LAG/SMEM/GONPs showed proper interactions, including electrostatic interaction between these materials. X-ray diffraction analysis revealed a lower degree of crystallinity in the nano-composite film by adding GONPs and SMEM. The Differential scanning calorimetry analysis conducted on the composite and optimized films, integrating SMEM and GONPs, revealed an elevation in both the glass transition temperature and the thermal degradation temperature compared to the blank sample. The results obtained from Field emission scanning electron microscopy demonstrated that the type and quantity of variables significantly influenced the surface morphology of the films, leading to the formation of cracks and pores in the film. Furthermore, the findings regarding antimicrobial activity demonstrated that the nanocomposite film, incorporating SMEM and GONPs, exhibited antimicrobial properties against E. coli and S. aureus bacteria. According to our result VEPI/LAG/SMEM/GONPs nanocomposite film possess potential to be used as environment friendly packaging films to improve shelf life of food. [ABSTRACT FROM AUTHOR]

This article details the development of an electrically-responsive bending actuator from a graphene oxide (GO), nanosized-ZnO, and sulfonated poly(vinyl alcohol) (S-PVA) nanocomposite membrane coated with platinum (Pt). The solution-cast S-PVA/ZnO/GO/Pt membrane exhibits an ion-exchange capacity of 1.68 meq g−1 and favorable electrochemical characteristics. With a 67.28% water uptake after a 4 h immersion at 45 °C, it serves as the foundation for an ionic polymeric-metal composite (IPMC) actuator. Electrolessly plated Pt layers ensure slow water loss (31.6% after 12 min at 6 V), enhancing long-term durability. Electromechanical characterization reveals a 10 mm tip displacement at 3 V, indicating improved investigations. The resulting IPMC nanocomposite with Pt coating demonstrates excellent mechanical, electrical, and electrochemical capabilities for diverse applications. Comprehensive analyses, including SEM, EDX mapping, TGA, and XRD, elucidate the membrane's characteristics. This refined nanocomposite holds promising potential across various applications, offering enhanced invetigations and durability in electrically-driven actuation systems. [ABSTRACT FROM AUTHOR]

In the present study, a quaternary composite consisting of α-ketoglutaric acid, chitosan, polyaniline, and graphene oxide (α-CTS-PANI-GO) was synthesized and characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, and Raman spectroscopy. The adsorption of dye on the film was proved by the X-ray diffraction analysis method. According to the increase in the intensity of the peak before and after adsorption, it showed the presence of Methylene Blue (MB) and Acid Orange 7 (AO7). Also, the appearance of peaks related to sulfur in Energy dispersive X-ray (EDX) and EDX elemental mapping, and X-ray photoelectron spectroscopy data after the adsorption process proved the presence of dyes compounds and their adsorption by the synthetic film. The simultaneous removal properties of α-CTS-PANI-GO were evaluated in the removal of cationic and anionic dyes, MB and AO7. Using the Central Composite Decomposition, the effect of different variables such as pH, temperature, adsorbent dose, and time on AO7 and MB removal was studied. The regeneration of α-CTS-PANI-GO film was studied and the zero point charge of the synthesized film was also determined. Various isotherm models, such as Langmuir and Freundlich, were investigated, and the processing of experimental equilibrium data confirmed the suitability and application of the Langmuir model. Analysis of experimental adsorption data using various kinetic models, such as pseudo-first and second-order models, shows the applicability of the first-order equation. The results showed that in the optimal conditions, the removal percentage was about 95% for AO7 and 80% for MB, which indicates the successful performance of the synthetic film compared to the method. [ABSTRACT FROM AUTHOR]