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The remarkable properties of graphene oxide, a shining dynamo, opened new possibilities for delivering the drug. The present work aims to fabricate a graphene-based porous hydrogel system that fades its side effects and encourages its utilization as a drug carrier. Graphene oxide was impregnated in the polymeric matrix for gastro-retentive drug delivery. Porogen was added to create a superporous structure. The extrusion-dripping technique is used to fabricate low density, super porous, and floating hydrogel beads, which were considered a practical approach to target the drug in a controlled and sustained manner in the stomach. The fabricated graphene oxide impregnates superporous beads were characterized by physicochemical analysis, morphological parameters, PXRD, swelling study, drug-release pattern, and in-vitro floating ability. The homogenous nature of fabricated samples was analyzed by weight and size variation. Micrometric properties were estimated to calculate the density and flow ability of superporous beads. The stability and shelf life of prepared hydrogels were performed by accelerated stability analysis according to ICH guidelines. Doxorubicin was chosen as a model anticancer drug. The pi–pi stacking technique is responsible for a considerable loading of the drug onto graphene oxide (GO). However, the successful preparation of low-density graphene oxide impregnates superporous hydrogel beads shows excellent floating ability, thus making it a promising candidate for stomach targeting. HIGHLIGHTS: The present work aims to fabricate a graphene-based porous hydrogel system that fades its side effects and encourages its utilization as a drug carrier. Graphene oxide was impregnated in the polymeric matrix for gastro-retentive drug delivery. Porogen was added to create a super porous structure. Doxorubicin was chosen as a model anticancer drug. The extrusion-dripping technique is used to fabricate low density, super porous, and floating hydrogel beads which were considered a practical approach to target the drug in a controlled and sustained manner in the stomach. We aimed to introduce a new concept of using hydrophilic polymers as fundamental excipients in the development of superporous hydrogel beads that would be promising candidate for stomach targeting and accelerate the drug release. These systems have potential advantages over previously reported carrier systems in terms of high drug loading, stability and the percentage of drug release was controlled at cancerous pH of about 70.34%. The in vitro and in vivo floating ability confirmed the beads float well in a gastric environment 6hrs. By integrating targeted modules of hydrophilic polymers, a novel synthesis approach enables the fabrication of low-density graphene oxide impregnates superporous hydrogel beads show excellent floating ability, thus making it a promising candidate for stomach targeting. [ABSTRACT FROM AUTHOR]

The objective of this study is to evaluate the performance and emission characteristics of a diesel engine using metallic graphene oxide (GO) and nonmetallic zinc oxide (ZnO) nanoparticles in a Mahua biodiesel blend (B20). At a concentration of 75 mg/L, both GO and ZnO nanoparticles were considered and a surfactant (CTAB) and a dispersant (TWEEN 80) were added at a 1:1 ratio for surface modification. The nanofuel samples were analyzed for stability using a spectrophotometer. The nanoparticles mixed with dispersants and surfactants have shown improved stability. In addition, the injection pressure was varied from 200 to 250 bar. Dispersion of GO and ZnO nanoparticles in BD20 improved performance parameters such as BTE and BSFC. In addition, there was a significant decrease in CO, HC, smoke, and NOx emissions. TWEEN 80-added GO and ZnO nanoparticles in B20 achieved the best results, followed by the CTAB-added nanoparticles. In addition, the operating parameters showed a favorable trend toward improvement at higher injection pressures. At 250 bar, BTE was improved by 4.24% and BSFC was reduced by 3.59% compared to diesel. Also, the CO, UHC, NOx, and smoke opacity were reduced by 47.05%, 15.12%, 18.96%, and 37.09% for B20 + ZnO75 mg/L + TWEEN75 mg/L, respectively. [ABSTRACT FROM AUTHOR]

The present work highlights the synthesis of graphene oxide (GO) modified polythiophene (PTh) for its application as an antibacterial agent as well as a visible light active photocatalyst. PTh was synthesized via the interfacial polymerization method using FeCl3 as initiator and then formulated as nanohybrids by mixing it in different weight ratios with graphene oxide (GO) i.e., 1 wt.%,3 wt.% and 5 wt. %. PTh and GO/PTh nanohybrids were characterized using FTIR, UV-visible, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The polymerization of PTh as well as modification of PTh with GO was confirmed by IR studies, while the shifting of electronic transitions of PTH upon modification with GO were confirmed by the UV-visible studies. The degradation of dyes, Alizarin Yellow (AY), Basic Blue (BB) and Congo Red (CR) was carried out via sonophotocatalysis under visible light using PTh and GO/PTh as catalysts for a period of 60 min. The GO/PTh revealed higher degradation efficiency as compared to PTh. To evaluate its effectiveness as an antibacterial agent against Bacillus subtilis, disk diffusion inhibitory assay was carried out under dark and light conditions. The results showed that PTh and GO/PTh nanohybrids had bactericidal properties, regardless of light exposure. The results of the minimal inhibitory concentration (MIC) assay indicated the nanohybrid of 3-GO/PTh had the lowest MIC, followed by 1-GO/PTh and 5-GO/PTh. [ABSTRACT FROM AUTHOR]

This work aims to study the responsive expansion of graphene oxide- acrylic elastomer (GO-Acry ER elastomer) under applied electric field. The GO was synthesized from graphite (GP) by using Hummer's method based on various the ratios of GP to oxidizing agent namely potassium permanganate. GO-Acry ER elastomer was prepared by painted GO as the polarized particle on circular Acry ER as elastomer matrix. The optimum condition of synthesized GO was 1:2 ratios of GP: oxidizing agent which provided a more crystallinity, smaller particle size, and higher pore volume. The circular actuation response of GO-Acry ER elastomer was stimulated by applying external stimuli under various electric field strengths and GO characteristics. The expansion of the GO-Acry ER elastomer increased with an increasing external electric field strength. The GO-Acry ER elastomer under adding GO of 1:2 ratios was the largest expansion with 50% strain under applied electric field of 300 kV/mm. When the electric field strength was > 300 kV/mm, the ER elastomer shrank owing to electrical breakdown. Thus, GO is a suitable choice due to its ease of preparation and fast electro-responsive properties. [ABSTRACT FROM AUTHOR]

Due to the versatile usage and applications of chromium compounds in the industry worldwide, the chromium ions are present in the major effluents from a broad range of industries. Cr(VI) which is highly hazardous and carcinogenic poses a serious threat to the our ecosystem and human health even at very low concentration limits. Cr(III) ions are also toxic to aquatic life, but they are less harmful than Cr(VI) ions. Therefore, detection and analysis of the toxic Cr(VI) and Cr(III) ionic species in waste water are an utmost important area of research. Various chemical reagents and the different methods which require expensive instrumentation used in the past for detection and determination of the non-biodegradable Cr(VI) ions suffer from serious limitations. The present review summarises the use of spectrophotometric methods of determination of Cr(VI) and Cr(III) ions from aqueous solutions with high sensitivity, selectivity, accuracy and at lesser costs. The use of chemical reagents such as diphenylcarbazide (DPC) and several other dye-based reagents for spectrophotometric determination of hazardous Cr ions in water samples is discussed. Additionally, the use of DPC reagent in developing advanced technologies such as microfluidic detection system, microfluidic paper-based analytical devices (µPADs) and 3D printed device with online spectrophotometric detection system for onsite monitoring of water samples is elucidated. Different methods for selective speciation and preconcentration of Cr(VI) ions prior to spectrophotometric determination in water samples with very low concentrations (as low as ppb) of Cr ions are also described. The emerging trends in detection and determination of carcinogenic Cr(VI) ions involving the use of novel and innovative technologies and different categories of nanomaterials are also elucidated in the present review. [ABSTRACT FROM AUTHOR]

This work reports a nontraditional modified Hummer's method to synthesize graphene oxide (GO) nanosheets by adjusting the oxidation process via a different-molarity potassium permanganate (KMnO4) solution instead of utilizing its powder. The effect of KMnO4 concentrations on the structural and morphological properties of GO nanosheets was studied. Oxidant solutions of 0.5 M, 1 M and 1.5 M were experimented to control the properties of the GO layers. Then, the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), Raman and ultraviolet-visible (UV–Vis) spectroscopes. Finally, oxidant concentration was optimized at 1 M by which thinner, high-quality crystalline GO layers and wider bandgap energy ( E g ) were obtained. It is thus confirmed that such a modification in the oxidation is a pioneering process to improve the GO properties. [ABSTRACT FROM AUTHOR]

Considering the special effect of wound treatment in the field of medicine, antibacterial wound dressings preparation is one of the main challenges in successful wound healing. In this research, a starch (St)/polyvinyl alcohol (PVA) nanofiberous mat modified with graphene oxide (GO)-silver nanowire (AgNW) hybrid was fabricated. Initially, silver nanowires were synthesized by the polyol method, then GO-AgNW nanoparticle was prepared as a biocompatible and antibacterial biofilm. Reducing the diameter of nanofibers due to the addition of starch and GO-AgNW nanoparticles leads to fibroblast proliferation, increased collagen secretion, reduced inflammation and wound closure. Nanofibrous mats showed significant antibacterial activity against Staphylococcus aureus and Escherichia coli microorganisms. The largest zone of bacterial inhibition was obtained for Starch/PVA nanofibers containing 8% GO-AgNWs hybrid (27.11 and 24.62 mm). The use of GO-AgNW nanoparticles without drugs is an important point due to the strong antibacterial property of silver nanowire. The measured contact angle of nanofibrous mats was in the range of 57.8° as a desirable level of hydrophilicity for wound dressings. The degree of swelling obtained about 491.12%, and the water vapor transmission rate of 2549 ± 36 (g/m2.day) as a proof for accelerating wound healing. Finally, the results indicated that St/PVA/GO-AgNWs composite electrospun fibers could be a suitable candidate for the treatment of infectious wounds, surgical wounds, minor burns, etc. [ABSTRACT FROM AUTHOR]

AbstractConductive hydrogels have promising prospects in wearable strain sensor applications. However, the complex and diverse application scenarios put forward higher requirements on the conductivity, anti-freezing, tensile, self-healing, adhesion, and moisture retention properties of the conductive hydrogel. In this study, a polymagnesium acrylate/glycerol/graphene oxide (PAMgA/GL/GO) conductive hydrogel is prepared by free radical polymerization method, with magnesium acrylate (AMgA) as the polymer monomer, glycerol (GL) as the antifreeze filler, and graphene oxide (GO) as the conductive filler. Adding GL not only enhances the antifreeze properties of the composite hydrogels but also improves the moisture retention. The addition of GO increases the conductivity and the gauge factor (GF) of the composite hydrogels. When the GO content is 0.6 wt.%, the PAMgA/GL/GO conductive hydrogel demonstrates excellent properties of antifreeze, conductivity, self-healing, adhesion, and sensitivity. These excellent properties make it suitable as a wearable strain sensor for accurately monitoring human joint movements and subtle physiological signals. [ABSTRACT FROM AUTHOR]

AbstractThe current study aimed to the preparation of graphene oxide impregnated chitosan– polyvinyl alcohol hybrid beads (GO/CS-PVA) for the removal of Reactive Black 5 (RB5) dye from wastewater solutions, presenting them as a cost-effective alternative for wastewater treatment. These hybrid beads were fabricated using a dripping technique in an aqueous solution. The surface and structure of the material before and after adsorption process were studied by analyzing FTIR spectroscopy and Scanning electron microscope (SEM) as well as adsorption capacity was also evaluated. The results proved the successful synthesis of GO/CS-PVA beads and elucidated the physical adsorption mechanism of RB5. SEM images revealed uniform spherical beads with a rough surface, approximately 752 μm in diameter. Additionally, the evaluation of adsorption capacity showed that the optimum condition for RB5 adsorption is at pH = 3 while the kinetic investigations revealed that the adsorption process adhered to the pseudo-second-order model, indicating a chemisorption reaction. Furthermore, an increase in temperature from 25 to 65 °C enhanced the maximum adsorption capacity of GO/CS-PVA beads by 34%. The cytotoxic effect of the hybrid as measured on adipose derived stem cells via the MTT assay was negligible. In conclusion, it was proved that the eco-friendly GO/CS-PVA beads adsorbents can efficiently remove RB5 from wastewater in practical applications. [ABSTRACT FROM AUTHOR]

AbstractA metal–organic framework (MOF-199) nanocomposite was coated on magnetic graphene oxide (MGO) as a sorbent (MGO/MOF-199) and used for the isolation of aromatic amines by magnetic solid-phase extraction (MSPE). The analytes subsequently determined using gas chromatography with a flame ionization detector (GC-FID). The sorbent mass, desorption solvent, extraction time, desorption time, and pH were optimized. The calibration plots demonstrate linear ranges from 0.1 to 500 ng mL−1 with correlation coefficients from 0.9908 to 0.9939. The limits of detection (LOD) were between 0.03 and 0.1 ng mL−1. To evaluate the repeatability, relative standard deviations (RSD) were evaluated for 0.1, 10, and 100 ng mL−1 of the aromatic amines, yielding values from 3.2% to 4.5%. The developed method was employed to extract aromatic amines from tap water, seawater, and spring water. The relative recoveries were from 97.2% to 99.9%. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSThis study focuses on enhancing cementitious materials by incorporating silanized graphene oxide (SGO) and superabsorbent polymers (SAPs), aiming to improve their mechanical and durability properties. The primary goal is to evaluate the effects of SGO/SAP composites on the hydration, absorption, shrinkage, and overall performance of concrete. The composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) to understand their microstructure. Mechanical and durability tests revealed that adding SGO/SAP composites significantly increased the mechanical strength and water absorption capabilities of the concrete. The compressive strength, split tensile strength, and flexural strength of the SGO/SAP-modified concrete were measured at 57 MPa, 4.90 MPa, and 8.25 MPa, respectively. Shrinkage tests demonstrated the composite hydrogel’s excellent water-holding capacity at 0.3 wt.% SGO/SAP, facilitating internal curing in concrete structures. FE-SEM analysis indicated a reduction in microcracks due to the presence of SGO/SAP. The improvements are attributed to the synergistic effects of SGO and SAP, which enhance water retention, dispersion, and interfacial bonding within the cementitious matrix. The microstructural studies confirmed the exceptional stability of the SGO/SAP-modified mix, emphasizing its potential as an additive to improve concrete properties. This research underscores the significant potential of SGO and SAP in advancing the performance of cement-based materials, highlighting their applicability in infrastructure development and construction for creating more durable and high-performing concrete structures. The SGO/SAP significantly enhances the durability of cement-based materials.The SGO/SAPs exhibit superior water absorption and retention properties.Enhanced mechanical strength of SGO/SAP hydrogel-modified concrete.The durability characteristics of cement mortar improved by SGO/SAP hydrogelA decrease in the agglomeration of nanocomposite particlesThe SGO/SAP significantly enhances the durability of cement-based materials.The SGO/SAPs exhibit superior water absorption and retention properties.Enhanced mechanical strength of SGO/SAP hydrogel-modified concrete.The durability characteristics of cement mortar improved by SGO/SAP hydrogelA decrease in the agglomeration of nanocomposite particles [ABSTRACT FROM AUTHOR]

Graphene-based nanomaterials have demonstrated significant potential in environmental applications and more particularly in water treatment, especially with the extensive use of emerging pollutants (EP). These pollutants originate either from wastewater treatment plants or agricultural activities. This study focused on the antibiotic amoxycillin which is most commonly administered to humans, livestock, and aquaculture to fight a multitude of infectious diseases. In order to understand the use of graphene oxide as an adsorbent in the removal of amoxycillin and to clarify the interfacial interaction at the molecular level, a Density Function Theory study at the B3PW91/cc-pVDZ level of theory, molecular dynamics simulation, and independent gradient model were performed to determine the structural and energetic properties, and to analyse the different interactions involved in the approach. The obtained results shows that AMX exhibits a nucleophilic behaviour whereas GO acts as an electrophile, and that the adsorption process occurs spontaneously via a parallel mode indicating strong interactions. It was established that the stability of the formed complexes is mainly due to the existence of both hydrogen bonds and Van der Waals type interactions. [ABSTRACT FROM AUTHOR]

The current paper is devoted to investigate the free and forced vibrational responses of the multi-phase angle-ply laminated nanocomposite beam with focusing on the occurrence of resonance phenomenon. The influence of uniform thermal loading and three-parameter Kerr substrate which can affect the resonance behavior of the structure is surveyed. Utilizing a superior nanofiller with the name of Graphene Oxide (GO) together with the macro-scale Carbon Fibers (CFs) will constitute a novel multi-scale hybrid reinforcement for the polymer matrix. The combination of the Halpin–Tsai micromechanical model and extended rule of the mixture is implemented to estimate the effective properties of this multi-scale hybrid nanocomposite. Refined higher-order beam theory is employed to obtain the displacement fields and then with applying Hamilton's principle, the governing equations are derived and analytically solved via Galerkin's exact solution method. Also, the presented results are validated with reputed works in open literature. Furthermore, some tabulated and graphical results are provided to reveal the effects of various parameters such as fibers' orientation angle, weight and volume fractions of reinforcements, different boundary conditions, beam's slenderness ratio, Kerr substrate parameters, excitation frequency and temperature change on the dynamic behavior of the proposed structure. [ABSTRACT FROM AUTHOR]

The incomplete reduction of graphene oxide (GO) yields reduced graphene oxide (rGO), characterized by a zero band gap and intrinsic layer stacking, thus constraining its practical utility across diverse domains. Fortunately, this challenge can be effectively addressed by employing a suitable substrate for the fabrication of MoS2/rGO heterostructures. Nanocomposites of MoS2/reduced graphene oxide (MoS2/rGO-700W and MoS2/rGO-560W) were synthesized using MoS2 and GO solutions as starting materials through microwave-assisted synthesis with microwave power treatments of 700W and 560W, respectively. Structural characterization results reveal that the particle size of MoS2 within the composites is notably smaller compared to that of pure MoS2. The MoS2/rGO-700W composite demonstrates a more homogeneous dispersion of MoS2 and features a well-developed hierarchical porous structure with increased pore volume and specific surface area. The MoS2/rGO-700W composite demonstrates elevated ID/IG ratio, C/O ratio and C = C peak area, suggesting that increased microwave power enhances the removal of oxygen-containing groups from rGO. This process significantly restores the extended conjugated structure of graphene, thereby offering enhanced conductivity at the MoS2 interface. Furthermore, the proposed strategy holds considerable theoretical value and provides significant insights for the development process of novel MoS2-based composite electrode materials. [ABSTRACT FROM AUTHOR]

A new graphene oxide-based liquid chromatography stationary phase was synthesized, characterized, and used for the first time in the separation of paracetamol and caffeine in pharmaceutical preparations under reversed phase conditions. For this purpose, graphene oxide was synthesized using the modified Hummers method, and Si-GO stationary phase was obtained by immobilizing graphene oxide on aminopropyl silica. The obtained graphene oxide, Si–GO and aminopropyl silica materials were characterized by XRD, SEM, TEM and FTIR analysis. Different mobile phases were used to separate drug molecules in order to determine the mechanism of interaction between drug molecules and the stationary phase. Once the appropriate solvent system was determined, optimum chromatographic parameters such as mobile phase composition (methanol percentage in water), flow rate and column temperature were determined. The linearity of the method was in the range of 0.989–0.997. The maximum relative standard deviation (% RSD) value was calculated as 0.54. Mean recoveries for paracetamol and caffeine were 98%–99%, respectively, and LOD and LOQ were 6 × 10−3 to 6.5 × 10−3 mg/L and 2 × 10−2 to 2.2 × 10−2 mg/L, respectively. The results showed that the new graphene oxide-based stationary phase could be used for the separation of paracetamol and caffeine in pharmaceutical preparations. [ABSTRACT FROM AUTHOR]

In this study, a cement-based composite was prepared using reduced graphene oxide (RGO) as a raw material via an ethanol liquid-phase mixing pre-dispersion process. The microstructure of cement-based composites with varying RGO contents was discussed, and a systematic investigation was conducted into the electromagnetic wave absorption (EWA) performance of RGO-cement composites within the frequency range of 2–18 GHz. The results indicate that the RGO content significantly impacts its wave absorption performance. Notably, at an RGO content of 3.0 wt%, the wave absorption performance experiences substantial enhancement. For instance, the minimum reflection loss (RLmin) of −48.33 dB at 8.9 GHz with a coating thickness of 2.6 mm is achieved, while an effective absorption bandwidth (EAB) of 5.02 GHz is attained with a thickness of only 1.6 mm, covering nearly the entire Ku-band. The incorporation of high specific surface area RGO into cement materials results in abundant interface polarization losses and additional electromagnetic wave transmission paths, effectively boosting the EWA performance. Consequently, these materials exhibit significant potential for applications in the field of electromagnetic wave shielding. [ABSTRACT FROM AUTHOR]

An efficient stable electrochemical method for the determination of thiophene as a sulfur model compound in gasoline has been investigated based on the electrodeposition of graphene oxide and dicyandiamide on graphite electrode by cyclic voltammetry. The electroactive layer performance was considered by linear sweep voltammetry and square wave voltammetry by examining scan rates and their relevant equations to evaluate the electrochemical parameters. This modified electrode has high electrocatalytic characteristics to irreversible electrooxidation of thiophene. The electron transfer coefficient (α) was equal to 0.78, the electron transfer rate constant (log KS) was 3.2 s−1, and the saturated adsorptive capacity of the electroactive substance at the electrode surface (Γmax) was 1.14 × 10−8 mol cm−2 at pH 8 at low working potential of 0.5 V versus Ag/AgCl reference electrode. Scanning electron microscopy of the surface revealed the nanostructure of electrodeposited films and the morphology. This sensor is capable of electrochemical response to thiophene over the concentration range from 25 to 250 nmol L−1 with a detection limit of 8.31 nmol L−1, and a quantification limit of 25.18 nmol L−1. The method's reliability was checked regarding the simulated gasoline samples and the desired response and sensitivity were provided. The wide dynamic range, low detection limit, favorable precision and accuracy, and fast response with no interferences confirm the ability of this sensor for thiophene determination. This nano-sensor can be used for electrochemical in-situ direct monitoring of liquid fuel desulfurization processes. [ABSTRACT FROM AUTHOR]

Fatigue in asphalt pavements is a major deterioration caused by repeated traffic loading. The objectives of this research were to investigate the fatigue performance of graphene oxide (GO) modified asphalt mixtures and evaluate the influence of temperature and stress level on the fatigue life of GO asphalt mixtures using response surface methodology (RSM). For this purpose, an indirect tensile fatigue test was conducted. The results showed that the application of GO increased the fatigue life of the asphalt mixture. The RSM analysis proposed a quadratic model with a high determination coefficient (R2 = 0.9977) to fit the experimental data. The ANOVA test showed that temperature, stress level, and GO percentage had a pronounced effect on the fatigue performance of the mixture. Furthermore, multi-objective optimization was used to achieve an optimized mixture proportion and verify the model's reliability by conducting validation experiments. The predicted and actual results were found to be in excellent agreement, with a variation of only 2.12%, suggesting that the model can accurately predict the fatigue life of the GO-modified asphalt mixture. [ABSTRACT FROM AUTHOR]

Composite electrospun nanofibers based on silk fibroin (SF), aminated reduced graphene oxide (NH2rGO), and oxidized-cellulose nanocrystals (AD-CNCs) were designed to promote the healing process by electrical conductivity. In this respect, CNCs were produced from cotton cellulose and oxidized in the presence of sodium periodate, and reduced GO was synthesized and functionalized with amine with p-anthranilic acid via an esterification reaction. Then the crosslink was prepared by the Schiff-base reaction between oxidized CNCs and NH2rGO. Electrospun nanofibers were prepared from silk fibroin, previously prepared from Bombyx Mori cocoons, AD-CNCs, and different ratios of NH2rGO. The SF/AD-CNCs/NH2rGO nanofibrous scaffold presented multiple propitious characteristics for cell proliferation and wound dressing including low cytotoxicity, a hydrophilic surface, thermal stability, and degradability. The physicochemical evaluations showed that with increasing the NH2rGO content, hydrophilicity and electroconductivity of nanofibers increased. The SF/AD-CNCs/NH2rGO biodegradable conductive scaffold with 2.5% NH2rGO content showed favorable nanofibrous structure, supporting and stimulating fibroblast cell proliferation and attachment. The SF/AD-CNCs/NH2rGO nanofibrous scaffold demonstrates the application potential in wound healing management. [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]

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]

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]

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]

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]

The present study is focused on the investigation and simultaneous optimisation of MQL-turning parameters with the application of the weighted Mayfly algorithm for sustainable machining of Nimonic 75. The nanofluid used for the experimental work is graphene oxide dispersed rice bran oil. The parameters of cutting velocity, feed rate, nozzle angle, and nozzle distance were considered for processing characteristics of force, roughness, and residual stress. The weight in the Mayfly algorithm is determined using a grey relational coefficient (GRC). The weight importance calculated for each response is compared with the different schemes in the algorithm. The result showed that the parameters with these schemes had different optimal values. At optimal factor levels determined using GRC in the Mayfly, the algorithm improved 'F-value = 0.40' compared to factor levels in other methods. Compared to experimental results, the optimised value reduces the surface roughness, cutting force, and residual stress by 30%, 3%, and 10%, respectively. The feed rate, cutting velocity, and nozzle distance are the most vital parameters for optimising the output response with the GRC-Mayfly process. [ABSTRACT FROM AUTHOR]

Rapid industrialisation has led to severe environmental pollution, mainly due to the discharge of organic pollutants into the waterbodies. The removal of organic compounds such as dyes and phenolic pollutants from the industrial effluents before it is discharged should be the top priority. This article synthesised a novel chitosan cross-linked polyaniline grafted graphene oxide (CS-PANI@GO) composite with variable morphology, enhanced surface area, low cost, biocompatibility, and notable characteristics of high malachite green (MG) and phenol adsorption capacity. The physicochemical properties of CS-PANI@GO were studied by FESEM, FTIR, XRD, RAMAN, BET, and BJH pore size distribution. FESEM analysis demonstrated that the surface of CS-PANI@GO composite is porous in nature. The BET surface area of the composite is 88.91 m2/g. The effect of various parameters such as temperature, pH of the solution, initial concentration of MG and phenol, adsorption time, and dosage were investigated, and the optimal values were recorded. The adsorption performance of CS-PANI@GO composite for both MG and phenol follows the pseudo-second-order model suggests chemisorption occurs in the process. For MG dye, the adsorption equilibrium data follows the Freundlich model and for phenol, the data follows the Langmuir model. The maximum uptake for MG dye and phenol were 699.022 mg/g and 198.254 mg/g, respectively. Thermodynamic data demonstrated that the process of MG and phenol adsorption was spontaneous, endothermic, and feasible. The recyclability study shows that after five cycles of regeneration, the composite has excellent adsorption performance. The adsorption mechanism is also proposed to be hydrogen bond, π-π interaction, and electrostatic attraction. Based on the present adsorption results under various parameter conditions, the synthesised novel CS-PANI@GO composite could be applied as an efficient adsorbent for the treatment of dyes and phenolic pollutants from wastewater. [ABSTRACT FROM AUTHOR]

This study was focused on the design and development of a new heterogeneous catalyst based on polyester (PE) fabric modified with graphene oxide nanosheets decorated with silver metallic nanoparticles (PE-rGO/Ag0), using a simple, easy, and effective approach. PE fabrics were coated by sonication with graphene oxide (GO) nanosheets followed by in situ deposition and reduction of silver nanoparticles over the GO surface, covering the PE fabric and producing PE-rGO/Ag0. The crystalline structure, surface morphology and chemical characteristics of the synthesised materials were identified by X-ray diffraction spectroscopy, scanning and transmission electron microscopy analyses (SEM and TEM) and by Fourier-transform infrared spectroscopy (FTIR), respectively. The catalytic performance of the prepared PE-rGO/Ag0 was assessed during the hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4). Experimental results indicate that PE-rGO/Ag0 with a surface of 6 cm2 (3x2 cm) showed the highest catalytic activity with an apparent reaction rate constant (Kapp) of 0.65 min−1. In addition, PE-rGO/Ag0 activity resulted to be comparable and significantly higher than previously reported values of silver-based catalysts. Remarkable stability values were achieved during different operating cycles without significant degradation in the catalytic activity, suggesting that PE-rGO/Ag0 can be used as a strong candidate in long-lasting chemical catalytic processes. [ABSTRACT FROM AUTHOR]

In recent years, antibiotics in aqueous solutions have drawn extensive attention due to their harmful effect on human health and the environment. In this study, efficient and rapid adsorption of two antibiotics, including tetracycline (TC) and cefazolin (CFZ) on synthesised montmorillonite (Mt)/nano zero-valent iron (nZVI)/graphene oxide (GO) from aqueous solutions was studied. The prepared adsorbent was characterised by scanning electron microscope (SEM), energy dispersive X-Ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and vibrating sample magnetometer (VSM). One-factor-at-a-time (OFAT) method was used to optimise the experimental factors. The maximum removal percentage was achieved at pH of 7, an adsorbent dosage of 0.4 g, contact time of 7 min = TC and 10 min = CFZ, initial concentration of 5 mg L−1, and a temperature of 298 K. The evaluation of isotherm models indicated that the Langmuir isotherm with a coefficient of determination (R2) value of 0.9992 for both antibiotics was selected as the best fitting model to describe the adsorption process. The maximum adsorption capacities (qmax) of Mt-nZVI-GO were obtained at 43.24 mg g−1 for TC and 20.36 mg g−1 for CFZ. Furthermore, the pseudo-second-order (PSO) kinetic model fitted well for TC (R2 = 0.9937) and CFZ (R2 = 0.9997). Thermodynamic parameters, i.e. adsorption Gibbs free energy (ΔG0), standard enthalpy (ΔH0), and standard entropy (ΔS0) were estimated. It was found that the adsorption had spontaneous and exothermic in nature. The results revealed that Mt-nZVI-GO could be used as a simple, efficient, and eco-friendly adsorbent for the simultaneous removal of contaminants in aqueous media. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) significantly enhances cement hydration. This study investigates the effects of GO on the early hydration and pore structure evolution of cement paste by examining its impact on the setting time and mechanical properties of cement-based materials. In situ monitoring of the hydration process and microstructural changes was conducted using low-field nuclear magnetic resonance technology. The findings reveal that GO's nucleation effect accelerates cement hydration, reducing the setting time and increasing both the hydration rate and degree. Moreover, hydration products utilize GO as a template, leading to adjusted morphologies and enhanced interlinking of C–S–H gels. This results in a marked reduction in porosity and a denser microstructure within the cement paste. Consequently, the early mechanical properties of the cement paste are improved, with a significant increase in flexural strength observed at 72 hours. These results suggest that GO, which is cost-effective, size-controllable and suitable for mass production, holds great potential for applications in cement-based materials. [ABSTRACT FROM AUTHOR]

In the treatment of wastewater incorporating inorganic and organic contaminants, graphene oxide and polymer-based nanocomposites have gained a lot of interest. In the current study, reduced graphene oxide (r-GO), polypyrrole (PPY) and silica (SiO2) based nanocomposite material (r-GO/PPY/SiO2) was utilised as an effective adsorbent for the removal of Pb2+ and Cu2+ ions from contaminated water. The r-GO/PPY/SiO2 was synthesised using an efficient and low-cost approach, and it was then analysed using various techniques. Under the employed adsorption conditions, this material was demonstrated to be a very efficient adsorbent for the decontamination of Pb2+ and Cu2+ ions in wastewater. The highest adsorption capacities of r-GO/PPY/SiO2 for Pb2+ and Cu2+ ions were evaluated to be 19.305 and 23.148 mg/g. The pseudo-second order rate constants have been determined as 90.9 and 66.225 mg/g/min for Pb2+ and Cu2+ ions, respectively. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) nanoreinforcement is shown to significantly improve the strength and durability of concrete at the expense of mix workability. While polycarboxylate superplasticizers (PCSP) addition has improved GO-cement/mortar strength and workability in existing literature, this article examines if this improvement is translated to concrete with lower cement and water contents. PCSP and GO showed colloidal instability and particulate aggregation through surface charge measurements, presumably caused by divalent Ca 2 + ion interbridging between the GO and PCSP. This chemical interference results in a 26% reduction in 28-day compressive strength and a 20% decrease in the workability of PCSP-treated GO-concrete. Microstructural examination reveals significantly larger pores in PCSP+GO cement than in GO-cement or PCSP-only cement due to the chemical interference induced by PCSP-GO interactions in cement and concrete. Hence, PCSP and GO interactions must be further researched for practical use in concrete structures. [ABSTRACT FROM AUTHOR]

AbstractGraphene oxide (GO) is widely used in bone tissue engineering due to its good biocompatibility and proliferation, and is often used in combination with other hydrogels, which not only reduces the cytotoxicity of GO but also improves the mechanical properties of the hydrogels. We developed injectable carboxymethyl chitosan (CMC)/hydroxyethyl cellulose (HEC)/β-tricalcium phosphate (β-TCP)/GO hydrogel via hydrogen bonding cross-linked between (CMC) and (HEC), also, calcium cross-linked by β-TCP was also involved to further improvement of mechanical properties of the hydrogel, and incorporate different concentration of GO in these hydrogel systems. The characterization of the novel hydrogel was tested by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The swelling ratio and mechanical properties were investigated, the results showed that the addition of GO was able to reduce the swelling rate of hydrogels and improve their mechanical properties, with the best effect in the case of 1 mg/mL content. In vivo experimental studies showed that the hydrogel significantly promoted the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs), with the best effect at a concentration of 2 mg/mL. The results of the cellular experiments were similar. Therefore, the novel environment-friendly and non-toxic injectable CMC/HEC/β-TCP/GO hydrogel system may have potential applications in bone tissue engineering. [ABSTRACT FROM AUTHOR]

In artificial intelligent retrieval, the evolution of smart electronic devices and wireless communication is a source of electromagnetic pollution (EMP), which is a severe global concern. Nowadays, conductive polymeric nanocomposites are exceptionally desirable for electromagnetic interference shielding (EMI) applications due to their good conductive and unique shielding properties. The aim of the present work is to study the EMI shielding effectiveness of thin films. For this purpose, we have synthesized PVA-based nanocomposite films. Reduced graphene oxide (rGO), and iron oxide nanoparticles were used as nanofillers. Nanoparticles of iron oxide were synthesized by the co-precipitation method, whereas rGO was synthesized by modified Hummer’s method. XRD (X-ray diffraction), FTIR (Fourier transform infrared) spectroscopy, (RBS), Rutherford backscattering spectroscopy, Current–Voltage (IV) measurements and Impedance spectroscopy were used for the characterization of nanocomposites, 3.5 dB, for iron oxide/PVA thin films at 12 GHz frequency range. rGO/PVA thin films with 0.125, 0.25 and 0.5 wt% were 4.2, 8.2 and 12.3 dB, respectively, at 12 GHz range. Such shielding materials have useful applications in military field and radar systems. These shielding films can be used to protect the electronic instruments from the light waves striking them. Its use also limits health hazards to the people living in extremely radiative environments. [ABSTRACT FROM AUTHOR]

Poly(2-aminothiazole) is a little-studied conducting polymer with sulfur and nitrogen heteroatoms in the aromatic ring, which reveals prospects for application in various fields. We studied the conditions of chemical synthesis of poly(2-aminothiazole) and its composite with graphene oxide in an aqueous solution, as well as electrochemical deposition on electrode surfaces – Pt and SnO2. The structure of the polymer was investigated by SEM and FT-IR spectroscopy. A quantum-chemical calculation using the semi-empirical PM7 method was carried out. The electrochemical activity of polymer films was examined. Increasing effective parameters of charge transport for poly(2-aminothiazole)/graphene oxide films were detected. [ABSTRACT FROM AUTHOR]

Practical work in the laboratory is a key aspect of the teaching-learning process in science because it allows students to acquire skills that are essential for carrying out experimental research. This is also a technique that provides meaningful learning. Microbiological control works with oxide graphene sheets (GO), which means a breakout of novelty in their formation courses to acquire a PhD degree. We designed this work to provide postgraduate students with microbiological, biochemical, technical, and interpretative tools for the analysis of the effect of GO on cell viability and membrane structure through an innovative laboratory in which the effect of nanomaterials on Pseudomonas aeruginosa was observed. In this way, the aim is to contribute to their postgraduate training, with quality information and techniques that students can appropriate, and then apply the to, or enrich, their research. At the end of this laboratory exercise, students will be able to interpret the consequences of GO on membrane damage and changes in membrane fatty acid composition. Innovative and authentic classroom research experiences are considered valuable building blocks for science at the university level, as well as for increasing student motivation, and linking research to teaching. [ABSTRACT FROM AUTHOR]

Nanostructured porous materials are desirable sorbents for separating and removing oil spills from water. This work examines the performance of the prepared efficient sorbents in the oil sorption process. Polyacrylonitrile (PAN) fibers served as the skeleton matrix, while glutaraldehyde and poly(vinyl alcohol) (PVA) served as cross-linking agents. The prepared polymer sorbents showed high adsorption capacity (12.47 g/g), porosity (95.41%) and low density (0.069 g/cm3). The incorporation of carbon nanostructures (nanotubes or graphene oxide) in the sorbent increased the adsorption capacity to 14.85 g/g. The hydrophobic nature of carbon nanotubes significantly increases the contact angle of water with the surface of the nanocomposite absorber and reaches 137.5 degrees. The obtained sorbents showed good reusability in the adsorption process and maintained an adsorption capacity of about 10 g/g after 5 cycles. The optimal temperature range for using nanocomposite sorbents was 25°C to 35°C. The combination of high sorption capacity, low porosity and density in modified polyacrylonitrile, along with its reusability, makes this designed sorbent highly suitable for efficient removal of oil spills. [ABSTRACT FROM AUTHOR]

The incompatible thermoplastic poly lactic acid/carboxylated acrylonitrile butadiene rubber (PLA/XNBR) was prepared, and the effect of graphene oxide (GO) as a reinforcement and glycidyl methacrylate (GMA)-grafted XNBR (XNBR-g-GMA) as a compatibilizer on the properties of PLA/XNBR blend was investigated in this research. The microstructure, mechanical behavior, thermal, rheology, and dynamic mechanical properties of PLA/XNBR composites were investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), tensile test, and dynamic mechanical thermal analysis (DMTA). The incorporation of XNBR-g-GMA improved the compatibility of the PLA/XNBR blend phases, as confirmed by microstructure and DMTA analysis. The results of the mechanical properties showed that with an increase in GO content in the PLA/XNBR/XNBR-g-GMA matrix, there was a significant improvement in tensile strength, Young's modulus, hardness, and impact strength. In order to validate the experimental mechanical and rheological results, various theoretical models were applied and a good agreement was observed between the theoretical and experimental data. [ABSTRACT FROM AUTHOR]

In this study, polyethylene glycol (PEG), as a sacrificial agent, and gelatin containing graphene oxide (GO) are co-electrospun to prepare scaffolds. Based on pore size measurements, removal of PEG leads to an increase in the pore size of modified scaffolds, resulting in easier infiltration. Moreover, noticeable elastic modulus of GO increased the mechanical strength. Alizarin red staining indicated proliferation and differentiation of human bone marrow-derived mesenchymal stem cells seeded on the modified scaffolds. Thus, gelatin scaffold containing 0.5% GO with 20% PEG at the ratio of 80:20 for gelatin–PEG was selected as the optimal scaffold for bone tissue engineering approaches. [ABSTRACT FROM AUTHOR]

The research aim is to develop pure epoxy composites (PEC), PTL-reinforced epoxy composites (PTLEC), PTL-loaded and E-glass fiber- incorporated epoxy composites (PTLEIEC), and PTL- and E-glass fabric and graphene oxide-incorporated epoxy composites (PTLEIEGO) were fabricated through an open molding hand layup technique, and structural, mechanical, and thermal stability were carried out and results were compared. Functional groups such as OH, -C-H, C=O, C=C, and C-OH, were found in PTL. Similarly, the OH, C-H, Si-O-Si, C=O, and C-H present in the PTLEIEGO composites were found through Fourier transform infrared spectroscopy (FTIR). The crystal plane orientations (110) and (220) in the PTLEIEGO composites were found through XRD. The surface morphology and elemental compositions of PTLEIEGO composites were found through field emissions electron microscopy (FESEM) and found the presence of different organic and inorganic elemental compositions such as C, O, Si, Ca, Zn, K, and Br as 77.85, 20.78, 0.33, 0.45, 0.05, 0.05, and 0.50 wt.% through energy dispersive X-ray (EDX) spectroscopy. The DSC and TGA were carried out and found the thermal stability of the composites and the onset melting temperature was found to 353.1˚ C. The maximum tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 1.25 MPa, 25 ± 0.5 MPa, 55 ± 0.5 MPa, 93 ± 0.5 MPa, and 120 ± 0.5 MPa as per ASTM D 638. The tensile strength was improved from 1.25 MPa for PTL to 120 ± 0.5 MPa for PTLEIEGO. The FEM results revealed a minimum error of 0 % and a maximum error of 21.38 % compared to the experimental results. The maximum shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 55 ± 0.5 SHN, 59 ± 0.5 SHN, 76.1 ± 0.5 SHN, and 81.4 ± 0.5 SHN, respectively, as per ASTM D2240. The flexural strengths of PEC, PTLEC, PTLEIEC, and PTLEIGO composites were found to be 37 ± 0.5 MPa, 43 ± 0.5 MPa, 94 ± 0.5 MPa, and 131 ± 0.5 MPa, respectively, as per ASTM D 790. The new composites would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands. The tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO were found to be 1.25, 25 ± 0.5, 55 ± 0.5, 93 ± 0.5, and 120 ± 0.5 MPa, respectively. The tensile strength of the experimental results was compared with FEM results. The shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIGO was determined to be 55 ± 0.5, 59 ± 0.5, 76.1 ± 0.5, and 81. 4 ± 0.5 SHN, respectively. The novel composite would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands. [ABSTRACT FROM AUTHOR]

The present work involves an eco-friendly, green, and cost-efficient synthesis of reduced graphene oxide using green extracts of curry leaves and Tulsi seeds as reducing agents. The synthesized reduced GOs (CL-rGO and TS-rGO) were confirmed by XRD, FESEM, EDS, FT-IR, UV-VIS, and TGA studies. The disappearance of the peak at 9.90° and the appearance of a new peak at 2θ = 24.56° and 2θ = 25.62° and a decrease in interlayer spacing from 0.88 nm to 0.34 nm and 0.36 nm in CL-rGO and TS-rGO respectively confirmed the synthesis of reduced GO. The C/O atomic ratio of CL-rGO and TS-rGO was found 4.35 and 4.19 as compared to synthesized GO (C/O atomic ratio 2.65) which confirmed the synthesis of reduced GO. Further, the catalytic applications of synthesized CL-rGO and TS-rGO were studied for the reduction of cinnamaldehyde to cinnamyl alcohol in an aqueous medium yielding 90-91%. Moreover, the degradation of methylene blue and malachite green dyes was studied and found that both dyes were eliminated within 25 and 30 min in dark conditions using CL-rGO and TS-rGO respectively. Both CL-rGO and TS-rGO showed significant antimicrobial activity against different fungal strains but specifically CL-rGO against M. furfur with the minimum inhibitory concentration of 125 µg/mL. Furthermore, CL-rGO and TS-rGO exhibited excellent antimicrobial activity against E. coli with minimum inhibitory concentrations of 62.5 µg/mL and 31.25 µg/mL, respectively. [ABSTRACT FROM AUTHOR]

Cobalt disulphide (CoS2), 3-amino-5-ethoxy-1,2,4-triazole (AET), and graphene oxide, also known as GO, were added to polyurethane (PU) coatings to improve their anticorrosion and fire-retardant properties. To analyze the structural and morphological behaviours of the films of pure CoS2, AET/CoS2, GO/CoS2, and GO/AET-CoS2, SEM/EDX, TEM, TGA, XPS, and XRD techniques were used. The peak heat release rate (PHRR) and total heat release (THR) of polyurethane-graphene oxide/AET-CoS2 were significantly lower than those of polyurethane, with differences of 64.7% and 52.8%, respectively, demonstrating better flame retardancy. The anticorrosive, hydrophobic, and flame-retardant characteristics of the PU-GO/AET-CoS2 nanocomposite were confirmed using mechanical testing and electrochemical methods. Impedance studies confirmed that the corrosion protection performance of PU-GO/AET-CoS2 in seawater was much greater (22,481 kΩ cm2) than that of the plain polymer (157 kΩ cm2). The PU-GO/AET-CoS2 nanocomposite coated AA7039 aluminium alloy had the lowest aluminium ion dissipation as evidenced by SECM investigations. The PU-GO/AET-CoS2 coating had superior hydrophobic properties (WCA: 164°). Therefore, PU-GO/AET-CoS2 could be exploited as a potential material for coatings in industrial processes. [ABSTRACT FROM AUTHOR]