Graphene Oxide-based Nanocomposites Research Articles

Optimizing in-situ upgrading of heavy crude oil via catalytic aquathermolysis using a novel graphene oxide-copper zinc ferrite nanocomposite as a catalyst

Unconventional resources, such as heavy oil, are increasingly being explored and exploited due to the declining availability of conventional petroleum resources. Heavy crude oil poses challenges in production, transportation, and refining, due to its high viscosity, low API gravity, and elevated sulfur and metal content. Improving the quality of heavy oil can be achieved through the application of steam injection, which lowers the oil’s viscosity and enhances its flow. However, steam injection alone falls short of meeting the growing demand for higher-quality petroleum products. Catalytic upgrading is therefore being investigated as a viable solution to improve heavy oil quality. This study experimentally investigates the application of two novel catalysts, namely copper-substituted zinc ferrite (ZCFO) synthesized via the sol–gel combustion method and a graphene oxide-based nanocomposite (GO-ZCFO) with different ratios, for catalyzing aquathermolysis reactions in the steam injection process, with the aim of enhancing the in-situ upgrading of heavy oil. These catalysts underwent characterization using X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM). Their catalytic performance was assessed utilizing a high-pressure/high-temperature reactor (300 ml), with a comprehensive analysis of the changes in the physical and chemical properties of the heavy oil before and after upgrading. This analysis included measurements of sulfur content, SARA fractions, viscosity, API gravity, and Gas Chromatography (GC) of saturated hydrocarbons and evolved gases. All upgrading experiments, including both catalytic and non-catalytic aquathermolysis processes, were conducted under a reaction time of 6 h, a reaction temperature of 320 °C, and high pressure (86–112 bar). The results indicated that the introduction of the proposed catalysts as additives into the upgrading system resulted in a significant reduction in sulfur content. This, in turn, led to a decrease in resin and asphaltene content, an increase in the content of saturated hydrocarbon, particularly low-molecular-weight alkanes, and ultimately, a reduction in viscosity along with higher API gravity of the crude oil. GO-ZCFO with a weight ratio (50:50) exhibited the best catalytic performance. The heavy crude oil, upgraded with this 50:50 ratio, exhibited significant enhancements, including a 29.26% reduction in sulfur content, a 21.27% decrease in resin content, a 37.60% decrease in asphaltene content, a 46.92% increase in saturated hydrocarbon content, a 66.48% reduction in viscosity, and a 25.49% increase in API gravity. In comparison, the oil upgraded through non-catalytic aquathermolysis showed only marginal improvements, with slight reductions in sulfur content by 5.41%, resin content by 3.60%, asphaltene content by 11.36%, viscosity by 17.89%, and inconsiderable increases in saturated hydrocarbon content by 9.9% and API gravity by 3.02%. The GO-ZCFO, with its high catalytic activity, stands as a promising catalyst that contributes to improving the in-situ upgrading and thermal conversion of heavy crude oil.

A Review on Graphene Oxide-Based Ferrite Nanocomposites for Catalytic Applications

A Review on Graphene Oxide-Based Ferrite Nanocomposites for Catalytic Applications

Synthesis, Characterization, And Application of Graphene Oxide-Based Nanocomposite for Furfural Adsorption

Objective: The objective of this study is to synthesize, characterize, and apply a novel graphene oxide-based adsorbent for the organic contaminant furfural, aiming to develop a new material with the capacity for removal of this heterocyclic aldehyde via the adsorptive method. Theoretical Framework: This empirical study utilized a bibliographic procedure to synthesize the adsorbents, investigate their efficacy in adsorbing furfural, and observe the kinetic characteristics of adsorption. The synthesized material was characterized to classify it based on its physical aspects. Method: The methodology adopted for this research includes the synthesis of the adsorbents, the evaluation of their adsorptive capacity for furfural removal, conducting adsorption kinetics, and studying the equilibrium and thermodynamics of adsorption. For the characterization of the adsorbents, analyses were performed using infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering, X-ray diffraction, and Raman spectroscopy. Results and Discussion: The results revealed that non-functionalized graphene oxide did not exhibit the capacity to adsorb furfural. The model that best fit the experimental data for the adsorption of furfural on thiol-functionalized graphene oxide was the pseudo-second-order model, indicating multilayer adsorption, applicable in both homogeneous and heterogeneous systems as mentioned in the literature. The thiol-functionalized graphene oxide demonstrated a furfural removal efficiency of approximately 60% under the studied conditions. According to the model, the thiol-functionalized graphene oxide exhibited a maximum adsorption capacity of 722.12 mg.g-1. Research Implications: This research contributes scientifically as this application has never been performed and presents a new material as an adsorbent for furfural, expanding the collection of materials capable of partially removing this contaminant from the aqueous environment. Originality/Value: This study contributes to the literature by verifying that the adsorbents developed in this work had not been used for the adsorption of the contaminant furfural, thus providing a contribution to scientific research in the application of graphene oxide. The relevance and value of this research are evidenced by the synthesis of a new adsorbent capable of partially decontaminating the organic compound from an aqueous solution.

Polymer-assisted synthesis of ternary magnetic graphene oxide nanocomposite for the adsorptive removal of Cr(VI) and Pb(II) ions

The presence of chromium [Cr(VI)] and lead [Pb(II)] ions in the water bodies have adverse effects on humans and aquatic life. Graphene oxide-based magnetic nanocomposites synthesized in the presence of chitosan (mGO/CS) or polyaniline (mGO/PA) as potential adsorbents for the removal of Cr(VI) and Pb(II) ions. The FTIR (Fourier transform infrared spectroscopy), EDX (Energy dispersive X-ray), XRD (X-ray diffraction) and SEM (Scanning electron microscopy) were employed to investigate the chemical composition, structural, elemental analysis, crystalline size and morphology of the nanocomposites. The FTIR results confirmed the synthesis of the nanocomposites by detecting peaks of specific functional groups. The average crystallite sizes of the mGO, mGO/CS, and mGO/PA nanocomposites were 17, 25, and 23 (nm), respectively, as determined by the Debye-Scherrer equation from the XRD data. Batch adsorption experiments were conducted for Pb(II) and Cr(VI) removal by varying the variables like pH, concentration of metal ions and contact time. The Box Behnken design (BBD) was used to optimize the adsorption parameters. Under the optimum conditions, mGO/CS and mGO/PA showed maximum removal percentages (%R) of 92.36 and 98.7 for Pb(II), and 85.25 and 93.08 for Cr(VI), respectively. The adsorption capacities were 110.84 and 118.44 mg/g for Pb(II), and 87.74 and 111.7 mg/g for Cr(VI) were obtained for mGO/CS and mGO/PA, respectively. The pseudo-second-order kinetic model and Langmuir isotherm fitted well to the experimental data and explain the adsorption mechanism of the nanocomposite materials for both metal ions.

Design of 3D printable boehmite alumina/thermally exfoliated reduced graphene oxide-based polymeric nanocomposites with high dielectric constant, mechanical and thermomechanical performance

In this study, melt-blending was employed to blend 80 wt% poly(lactic acid) and 20 wt% poly(ε-caprolactone) (80 %PLA/20 %PCL) with boehmite alumina-thermally exfoliated reduced graphene oxide (BA-TERGO) as nanofillers. Herein, we present a novel synergy effect of BA/TERGO particles on improving the dielectric constant while maintaining dielectric loss at lower magnitudes. Also, improving the thermomechanical properties of tough PLA/PCL nanocomposite through the incorporation of a dual-filer system strategy. Consequently, remarkable increase in dielectric constant was achieved for BA-TERGO/blend nanocomposite. In particular, the blend exhibited dielectric constant of about 2.91, while the BA-TERGO/blend nanocomposite exhibited dielectric constant of about 4.93 at a frequency of 2.0 ×106 Hz and a temperature of 190 ºC. On the other hand, tensile modulus of the BA-TERGO/blend nanocomposite increased from 1908.5 MPa to 2505.2 MPa and the tensile strength increased from 70.48 MPa to 96.3 MPa when compared to that of the neat blend. BA-blend and BA-TERGO/blend nanocomposites provided the improved storage modulus and thermal stability. This finding renders PLA-based biodegradable materials suitable for tough 3D printable material with potential for integrated circuits applications.

Synergistic advancements in nanocomposite design: Harnessing the potential of mixed metal oxide/reduced graphene oxide nanocomposites for multifunctional applications

Reduced graphene oxide-based nanocomposites find applications in designing and fabrication of smart materials due to their unique optical, electrical, mechanical, sensing, photochemical, and energy-storing capacities. This comprehensive review article explores different synthetic pathways employed in fabricating reduced graphene oxide (rGO)/metal oxides based nanocomposites (NCs) with improved properties for multifaceted applications. The different applications of the mixed metal oxide/rGO NCs were explored in gas sensing, photocatalysis, energy storage, and biomedical applications. Through comparative assessments, this review focuses on the change in optical, physical, chemical, mechanical, electrical, photocatalytic, sensing, charge storing, and antibacterial properties as we move from mixed metal nanoparticles and pure rGO to NCs. This review article opens the door for the design and synthesis of rGO-based multifunctional composite materials by providing insightful information about the development and design of mixed metal oxide/rGO NCs. The findings presented herein hold the potential to revolutionize future endeavors in energy storage, sensing, photocatalysis, adsorption, catalytic processes, purification, separation, protective coatings, and beyond.

Graphene Oxide-Based Nanocomposites for Stereolithography (SLA) 3D Printing: Comprehensive Mechanical Characterization under Combined Loading Modes.

Additive manufacturing, particularly Stereolithography (SLA), has gained widespread attention thanks to its ability to produce intricate parts with high precision and customization capacity. Nevertheless, the inherent low mechanical properties of SLA-printed parts limit their use in high-value applications. One approach to enhance these properties involves the incorporation of nanomaterials, with graphene oxide (GO) being a widely studied option. However, the characterization of SLA-printed GO nanocomposites under various stress loadings remains underexplored in the literature, despite being essential for evaluating their mechanical performance in applications. This study aimed to address this gap by synthesizing GO and incorporating it into a commercial SLA resin at different concentrations (0.2, 0.5, and 1 wt.%). Printed specimens were subjected to pure tension, combined stresses, and pure shear stress modes for comprehensive mechanical characterization. Additionally, failure criteria were provided using the Drucker--Prager model.

Graphene oxide-based nanocomposites for outstanding eco-friendly antifungal potential against tomato phytopathogens

To obtain the collaborative antifungal potential of nanocomposites conjugated with graphene oxide (GO), a combination of GO with chitosan (CS/GO) and GO with chitosan (CS) and polyaniline (PANI/CS/GO) was carried out. The synthesized GO-nanocomposites were recognized by several techniques. Vanillin (Van.) and cinnamaldehyde (Cinn.) were loaded on the prepared nanocomposites as antioxidants through a batch adsorption process. In vitro release study of Van. and Cinn. from the nanocomposites was accomplished at pH 7 and 25°C. The antimicrobial activity of GO, CS/GO, and PANI/CS/GO was studied against tomato Fusarium oxysporum (FOL) and Pythium debaryanum (PYD) pathogens. The loaded ternary composite PANI/CS/GO exhibited the best percent of reduction against the two pathogens in vitro studies. The Greenhouse experiment revealed that seedlings' treatment by CS/GO/Van. and PANI/CS/GO/Van significantly lowered both disease index and disease incidence. The loaded CS/GO and PANI/CS/GO nanocomposites had a positive effect on lengthening shoots. Additionally, when CS/GO/Cinn., CS/GO/Van. and PANI/CS/GO/Van. were used, tomato seedlings' photosynthetic pigments dramatically increased as compared to infected control. The results show that these bio-nanocomposites can be an efficient, sustainable, nontoxic, eco-friendly, and residue-free approach for fighting fungal pathogens and improving plant growth.

Synthesis, characterization, and FDTD simulations of Ag-enriched RGO nanosheets for catalytic reduction of 4-nitrophenol

Reduced graphene oxide-based nanocomposites are eminent materials having diverse applications including environmental remediation. The present work emphasizes the facile one-step co-reduction method for synthesizing silver nanoparticle (Ag NPs) decorated reduced graphene oxide (RGO) for catalytic reduction of 4-nitrophenol. FDTD simulation studies justify the experimental results, and XRD studies confirmed the reduction of graphene oxide and the formation of Ag NPs with reduced graphene oxide (AgRGO) composite. Raman analysis complements the structure, crystallinity, and defects in the fabricated material. XPS analysis verifies the reduction of graphene oxide (GO) into RGO and the decoration of metallic Ag on the surface of RGO. FESEM image showed the decoration of Ag NPs on the surface of RGO. AgRGO exhibited appreciable catalytic performance for reducing 4-nitrophenol in the presence of sodium borohydride compared to GO and RGO.

Radiofrequency driving antitumor effect of graphene oxide-based nanocomposites: a Hill model analysis.

Aim: This report proposes using the Hill model to assess the benchmark dose, the 50% lethal dose, the cooperativity and the dissociation constant while analyzing cell viability data using nanomaterials to evaluate the antitumor potential while combined with radiofrequency therapy. Materials & methods: A nanocomposite was synthesized (graphene oxide-polyethyleneimine-gold) and the viability was evaluated using two tumor cell lines, namely LLC-WRC-256 and B16-F10. Results: Our findings demonstrated that while the nanocomposite is biocompatible against the LLC-WRC-256 and B16-F10 cancer cell lines in the absence of radiofrequency, the application of radiofrequency enhances the cell toxicity by orders of magnitude. Conclusion: This result points to prospective studies with the tested cell lines using tumor animal models.

Architecture of GO/CoFe2O4/ZnO nanocomposite for efficient fluoride removal: An approach using RSM, ANN and GRU modeling

The presence of fluoride in wastewater possesses a significant risk to the environment. Graphene oxide-based nanocomposites were prepared as potential adsorbents for fluoride removal from water. Various techniques including X-ray diffraction (XRD), Scanning Electron Microscopy (FE-SEM), Energy dispersive X-ray (EDX), Fourier Transform Infrared Spectroscopy (FTIR), RAMAN spectroscopy, Ultraviolet-Visible spectroscopy (UV–vis), Vibrating Sample Magnetometer (VSM), X-ray Photoelectron Spectroscopy (XPS), Brunauer Emmett Teller (BET), and Electrochemical Impedance Spectroscopy (EIS) were employed to investigate the morphological, structural, chemical composition, elemental analysis, surface area, optical band gap, etc. of the CoFe2O4, CoFe2O4/ZnO composite and GO/CoFe2O4/ZnO nanocomposite. XRD analysis confirmed a reduction in crystallite size to 15.7 nm of GO/CoFe2O4/ZnO. Batch adsorption studies were conducted for fluoride removal with input independent variables (pH, temperature, initial fluoride concentration, time, and an adsorbent GO/CoFe2O4/ZnO dosage). The Response Surface Methodology (RSM) and Gated Recurrent Unit (GRU) models predicted the fluoride removal process, with RSM achieving an optimal fluoride removal of 94.3%, GRU achieving 94.5% and Artificial neural network (ANN) attaining 93.72%. A kinetic investigation was carried out using Pseudo first order (PFO) and Pseudo second order (PSO). Results confirmed that the adsorption of fluoride followed the PSO kinetic model with an (R2 = 0.999). Isotherm studies were conducted using Langmuir, Temkin, Freundlich, and Dubinin Radushkevich isotherms. Among them, the best model follows an adsorption mechanism, with (R2 = 0.984) and an adsorption capacity of 10.68 mgg−1 was Langmuir Isotherm. The real water sample of Ravi River, Pakistan also investigated for fluoride removal capability. This research contributes to the promotion of RSM and GRU modeling with high sustainability for water purification. The contemplated nanocomposite (GO/CoFe2O4/ZnO) is a potential adsorbent for the mechanism of water detoxification containing fluoride which may be useful for environmental remediation as well.

Evaluation of the effect of graphene oxide-based nanocomposites on smear layer by a scanning electron microscope: Laboratory investigation.

This study is to examine the effect of graphene oxide (GO) and GO-based nanocomposites (GO_EDTA, GO_CHIT) on the smear layer by scanning electron microscopy (SEM). Sixty human single-rooted anterior teeth were used. Samples were randomly categorised into six groups. Distilled water in group 1, 17% EDTA in group 2, chitosan (CHIT) solution in group 3, GO solution in group 4, GO_EDTA solution in group 5 and GO_CHIT in group 6 were used as irrigation solutions. Photomicrographs were acquired from the coronal, middle and apical parts of the samples by SEM. Statistical analyses were performed using Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests. There was a statistically significant difference among the groups (p < 0.003). Adding GO to CHIT and EDTA did not affect removing the smear layer in all segments (p < 0.003). Incorporating GO into EDTA and CHIT solutions did not change their interaction with the smear layer.

Waste plastics derived reduced graphene oxide-based nanocomposite with Fe3O4 for water purification and supercapacitor applications

Whether plastic waste ends up in a landfill or washed into the ocean, the ecological consequences of plastic pollution remain a constant challenge. In this work, we showcased how plastic waste derived reduced graphene oxide (WrGOs) and its composite with Fe3O4 (WrGOs-Fe3O4) can be used to remove drugs from water treatment plants and for energy storage applications specifically supercapacitors. WrGOs and WrGOs-Fe3O4 showed the removal efficacy of diclofenac and caffeine drugs from water samples with Qmax 11.06 mg/g and 15.1 mg/g for diclofenac, and 8.77 mg/g and 15.24 mg/g for caffeine. For energy storage purposes, WrGOs-Fe3O4 was first examined in a three-electrode setup using 1 M H2SO4 as an electrolyte along with the WrGOs. The composite WrGOs-Fe3O4 demonstrated a good specific capacitance of 488F/g at 1 A/g current density. For practical application, a Supercapacitor (SC) device was fabricated using WrGOs-Fe3O4 as electrode material in a two-electrode setup which exhibited excellent energy density (52.57 Wh/Kg at 0.5 A/g), high cyclic stability (90.03 %) and wider potential window of 1.4 V in 1 M H2SO4 aqueous electrolyte due to stronger ionic diffusion. Thus, this study begs the question: Can graphene-based composite products derived from waste plastic be exploited for drug removal and supercapacitor applications?

Development of graphene oxide-based polypyrrole nanocomposite for effective removal of anionic and cationic dyes from water

The majority of toxins, including metal ions, organic wastes, particularly dyes, and other inorganic wastes, are released into the environment today as a main problem of increased industry. These pollutants primarily disrupt the balance of the environment and harm people's health. In this work, attempts were taken to develop a graphene oxide-based nanocomposite with polypyrrole (GO/PP) as a versatile adsorbent. Initially, GO/PP nanocomposites were prepared with different GO/PP ratios, and initial adsorption studies were conducted towards organic dyes, lead ions, cadmium ions, and fluoride ions to identify the best ratio. GO/PP with a 20:80 ratio was identified as the most efficient adsorbent out of all the prepared materials. This material was characterized to identify its crystallinity, morphology, functional groups, and thermal properties using the X-ray diffractometer (XRD) technique, Scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), UV–visible spectrometer, and Raman spectroscopy. In this work, we report the adsorption properties of cationic rhodamine B (RhB) and anionic methyl orange (MeO) towards GO/PP 20:80 nanocomposites. The best-fitted kinetic model for both dyes was the pseudo-second-order model. The calculated dye removal efficiency for MeO and RhB was 98.40% and 99.90% within a contact time of 30 min and 10 min respectively at optimum pH of 7. The best-fitted isotherm model for RhB was the Freundlich model with 10.52 mg g−1 and the best-fitted isotherm model for MeO was the Langmuir model with 9.61 mg g−1 maximum adsorption capacities. The studies indicated that GO/PP can be used in gravity filtration and can effectively be regenerated.

1D iron vanadate-reduced graphene oxide nanorod composite for efficient oxidative esterification of aldehydes

In this paper, we report a facile and one-pot hydrothermal synthesis of FeVO4-rGO nanorod composite and its application as a heterogeneous catalyst in the oxidative esterification reaction of aldehydes using hydrogen peroxide oxidant. The nanomaterial is thoroughly characterized by different techniques, namely, XPS, FESEM, elemental mapping, XRD, Raman, HRTEM, etc. The as-prepared nanocatalyst shows good activity for the controlled base-free oxidative esterification of various aromatic aldehydes in alcohol solvents under refluxing conditions, achieving good yields of the desired esters. Furthermore, the substrate scope was explored over a wide array of substituted aromatic aldehydes with diverse electron-withdrawing and electron-donating groups in the phenyl ring. The presence of heterogeneous interfaces-induced properties in the nanorod composite results in synergistic effects to provide good catalytic performance. Thus, binary transition metal oxide-reduced graphene oxide-based nanocomposite as a nanocatalyst can open doors for efficient and sustainable esterification of aromatic aldehydes and aliphatic alcohols under oxidative conditions.

Design of ternary CeO2/Fe2O3/reduced graphene oxide-based hybrid nanocomposite for superior photocatalytic degradation material for organic dyes

Green energy and environmental preservation are becoming two foremost concerns in the human society. A successful strategy for addressing the issue of environmental pollution the photocatalytic application was helped to breakdown the harmful substances and sterilization of microorganisms in the presence of catalyst and sunlight. Herein, we introduced a serious of ternary CeO2/Fe2O3/r-GO based hybrid nanocomposite as an efficient catalyst for dye-degradation process. The effective catalyst was prepared via simple hydrothermal method assisted with annealing route. The hybrid catalyst was subjected to the XRD, FTIR, SEM and UV-DRS to estimate the structural and optical properties. Based on the study, the hybrid CeO2/Fe2O3/r-GO nanocomposite was exposed the brilliant absorption characteristics phenomena, and photocatalytic activities with remarkable stability. The methylene blue and methylene orange dye degradation activities were estimated using with the prepared hybrid nanocomposite. Fascinatingly, the hybrid CeO2/Fe2O3/r-GO catalyst was delivered the 90% and 86% dye-degradation result in the methylene blue and orange dyes under the UV light irradiation. Additionally, CeO2/Fe2O3/r-GO composite was gratefully recycled for five photodegradation sequences without experiencing any substantial changes to its activity or crystalline characteristics. The improved photocatalytic activity of the CeO2/Fe2O3/r-GO catalyst was mainly permitted to the synergic effects of the heterojunctions in the interface. The study's goal is to provide a good understanding for designing a suitable visible-light-driven photocatalyst with acceptable environmental remediation.

Effects of Film Confinement on Dielectric and Electrical Properties of Graphene Oxide and Reduced Graphene Oxide-Based Polymer Nanocomposites: Implications for Energy Storage

2D nanofillers such as graphene oxide (GO) and reduced GO (rGO)-based polymer nanocomposites have emerged as crucial materials for various applications, from flexible solid-state capacitors to electromagnetic interference (EMI) shielding devices. Specifically, the dielectric breakdown strength (EBD) and dielectric constant of polymer nanocomposite capacitors determine their ability to store energy, whereas frequency-dependent loss is crucial for EMI shielding applications. The miniaturization of energy storage and electronic devices demands a detailed understanding of the behavior of these polymer nanocomposites in the thin-film regime (micron to sub-micron thicknesses). In this work, we demonstrate the effect of confinement on the dielectric, electrical, and capacitive energy storage properties of the polyvinylidene fluoride (PVDF)–GO and PVDF–rGO films. We show that the dielectric permittivity is significantly impacted by the nanofiller confinement in thin (≈1 μm) PVDF polymer films, which is comparable to the lateral dimension of these 2D nanofillers. In thin PVDF–GO films, the nanofillers (and associated surface dipoles) become oriented quasi-parallel to the film interfaces, affecting the relative projected area to the applied electric field. The conductivity and loss tangent values increased as a function of frequency with reduced film thickness, which is beneficial to EMI shielding application. The EBD of the confined GO-based films was found to be relatively independent of the filler fraction, whereas rGO-based films increased with the filler fraction after an initial decrease. These results provide fundamental insights into rational design principles for using ultrathin GO and rGO-based polymer nanocomposite films in next-generation flexible electronic and energy storage devices.

Fabrication and characterization of graphene oxide-based polymer nanocomposite coatings, improved stability and hydrophobicity

In this study, acrylic-epoxy-based nanocomposite coatings loaded with different concentrations (0.5–3 wt.%) of graphene oxide (GO) nanoparticles were successfully prepared via the solution intercalation approach. The thermogravimetric analysis (TGA) revealed that the inclusion of GO nanoparticles into the polymer matrix increased the thermal stability of the coatings. The degree of transparency evaluated by the ultraviolet–visible (UV–Vis) spectroscopy showed that the lowest loading rate of GO (0.5 wt.%) had completely blocked the incoming irradiation, thus resulting in zero percent transmittance. Furthermore, the water contact angle (WCA) measurements revealed that the incorporation of GO nanoparticles and PDMS into the polymer matrix had remarkably enhanced the surface hydrophobicity, exhibiting the highest WCA of 87.55º. In addition, the cross-hatch test (CHT) showed that all the hybrid coatings exhibited excellent surface adhesion behaviour, receiving 4B and 5B ratings respectively. Moreover, the field emission scanning electron microscopy (FESEM) micrographs confirmed that the presence of the functional groups on the GO surface facilitated the chemical functionalization process, which led to excellent dispersibility. The GO composition up to 2 wt.% showed excellent dispersion and uniform distribution of the GO nanoparticles within the polymer matrix. Therefore, the unique features of graphene and its derivatives have emerged as a new class of nanofillers/inhibitors for corrosion protection applications.

NANOCOMPOSITE MATERIALS BASED ON GRAPHENE, GRAPHENE OXIDE, AND SILVER NANOPARTICLES

In this work, plasmon characteristics of nanocomposite materials based on graphene, graphene oxide, and silver nanoparticles have been studied. The effective dielectric constant and absorption coefficient of the nanocomposites based on graphene-silver and graphene oxide – silver depending on the concentration and size of nanoparticles have been calculated. A change in the silver nanoparticles filling factor by 5 percent leads to significant changes in both the real and imaginary parts of the effective dielectric constant of the nanocomposite material. A pronounced absorption peak is observed in the case of graphene-based nanocomposite with a silver filling factor of 0.2. At the same time, the absorption peak can be indicated at a silver filling factor of 0.1 for the graphene oxide-based nanocomposite. The maximum absorption is observed for the nanocomposite material with nanoparticles having a radius of 5 nm in both cases. The researched nanocomposite materials can be successfully used for various organic electronics applications.

Synthesis and electrochemical study of enzymatic graphene oxide-based nanocomposite as stable biosensor for determination of bevacizumab as a medicine in colorectal cancer in human serum and wastewater fluids

This work's goal was the fabrication of a graphene oxide-based nanocomposite biosensor for the determination of bevacizumab (BVZ) as a medicine for colorectal cancer in human serum and wastewater fluids. For the fabrication electrode, graphene oxide was electrodeposited on GCE (GO/GCE), and then DNA and monoclonal anti-bevacizumab antibodies were immobilized on the GO/GCE surface, respectively (Ab/DNA/GO/GCE). Structural characterization using XRD, SEM, and Raman spectroscopy confirmed the binding of DNA to GO nanosheets and the interaction of Ab with the DNA/GO array. Electrochemical characterization of Ab/DNA/GO/GCE using CV and DPV indicated immobilization of antibodies on DNA/GO/GCE and sensitive and selective behavior of modified electrodes for determination of BVZ. The linear range was obtained 10–1100 μg/mL, and the sensitivity and detection limit values were determined to be 0.14575 μA/μg.mL−1 and 0.02 μg/mL, respectively. To verify the applicability of the planned sensor for determination of BVZ in human serum and wastewater fluid specimens, the outcomes of DPV measurements using Ab, DNA, GO, and GCE and the results of the Bevacizumab ELISA Kit for determination of BVZ in prepared real specimens showed good conformity between the outcomes of both analyses. Moreover, the proposed sensor showed considerable assay precision with recoveries ranging from 96.00% to 98.90% and acceptable relative standard deviations (RSDs) below 5.11%, illustrating sufficiently good sensor accuracy and validity in the determination of BVZ in prepared real specimens of human serum and wastewater fluids. These outcomes demonstrated the feasibility of the proposed BVZ sensor in clinical and environmental assay applications.