Papers by Keyword: Graphene Oxide

Abstract: Synthetic dyes such as methyl orange (MO) are persistent water pollutants that pose serious environmental and health hazards due to their toxicity and resistance to biodegradation. Developing efficient, sustainable, and reusable adsorbents for dye removal remains a major challenge in wastewater treatment. This study presents the design and optimization of chitosan/polyethyleneimine/graphene oxide (CS/PEI/GO) hydrogel nanocomposite beads synthesized through controlled cross-linking with glutaraldehyde (GLA) for enhanced adsorption of MO from aqueous solutions. A Box–Behnken experimental design coupled with response surface methodology (RSM) was employed to evaluate the effects of PEI, GO, and GLA concentrations on adsorption capacity. Statistical analysis confirmed the high significance of the cubic model (F = 38.34, p = 0.0001) with a non-significant lack of fit, validating its strong predictive reliability. PEI concentration had the most pronounced effect, providing protonated amine sites for electrostatic interaction with the anionic dye, while GO increased surface area and provided oxygen-containing groups that enhanced hydrogen bonding and π–π interactions. GLA served as a cross-linker to stabilize the hydrogel structure without deactivating active sites. The optimized composition (2.0% PEI, 900 ppm GO, and 2.5% GLA) achieved a predicted adsorption capacity of 23.16 ± 1.05 mg/g, which closely matched the experimentally obtained value of 23.31 ± 1.19 mg/g, with only 2.2% deviation. These findings confirm that the CS/PEI/GO hydrogel nanocomposite provides a balanced integration of structural stability, functional site availability, and high adsorption efficiency, demonstrating its potential as a scalable, eco-friendly material for advanced dye removal and sustainable wastewater treatment.

Abstract: The performance of polymer electrolyte can be improved through various approaches, including the addition of filler and dopant salt, in which has demonstrated significant potential for enhancing performance in electrochemical applications. The purpose of this study was to investigate the ionic conductivity and structural studies of 49% poly (methyl methacrylate) grafted natural rubber (MG49)-graphene oxide (GO) integrated with ammonium triflate (NH₄CF₃SO₃) based polymer electrolytes. The highest ionic conductivity, 4.42 x 10^-6 Scm^-1, was achieved with 25 wt.% of NH₄CF₃SO_3. ATR-FTIR analysis showed a reduction in C=O peak intensity, indicating interaction between the polymer matrix and salt, while optical microscopy (OM) revealed that the 25 wt.% sample had the smoothest surface and the most amorphous structure, correlating with the highest ionic conductivity. These results suggest that nanocomposite polymer electrolytes based on MG30-GO-NH₄CF₃SO₃ have potential for energy storage applications.

Abstract: Enhanced Oil Recovery (EOR) methods are increasingly essential as traditional extraction techniques face declining efficiency and mounting environmental concerns. Nanotechnology offers a promising approach by integrating engineered nanomaterials such as carbon nanotubes (CNTs), graphene oxide, and metal oxide nanoparticles to improve oil displacement. This study evaluates the role of nanomaterials in modifying wettability, reducing interfacial tension, and enhancing mobility control in reservoirs. Experimental results show that optimized CNT concentrations increase oil recovery by up to 18%, while graphene oxide achieves a 22% enhancement. Additionally, the integration of artificial intelligence (AI) with nanoEOR enables real-time optimization of nanofluid deployment. Despite notable progress, challenges such as nanoparticle stability, economic feasibility, and environmental impact remain. Addressing these challenges through advanced synthesis methods, scalable nanofluid production, and AI-driven predictive modeling will accelerate the commercialization of nanoEOR technologies, facilitating more sustainable and efficient oil extraction.

Abstract: Graphene, a 2D carbon allotrope with remarkable characteristics like high conductivity, large surface area has shown potential as a good candidate for high-performance supercapacitors. The processability of its derivative, graphene oxide, into fibers enables the development of miniaturized wearable energy storage devices. However, the synthesis of pure graphene oxide and its subsequent reduction to restore conductivity remain a focus for research. Herein, we employ the improved Hummers’ method for graphene oxide synthesis, followed by meticulous washing to remove residual acids. The obtained graphene oxide was then transformed into conductive graphene fibers through a wet-spinning and hydroiodic acid (HI) reduction process. The resulting fibers showed a high areal capacitance of 175 mA cm⁻² in a three-electrode system. When assembled into a flexible supercapacitor, these fibers delivered an energy density of 8 μWh cm⁻² and areal capacitance of 60 mA cm⁻². This study demonstrates the potential of our strategy for fabricating fiber-based energy storage devices based on graphene.

Abstract: This study presents the development and optimization of polypyrrole/graphene oxide (PPy/GO) gas sensors for accurate and reliable coffee aroma detection. By systematically varying the PPy/GO film thickness, we determined the optimal configuration to maximize sensor sensitivity and response time. The optimized sensor demonstrated exceptional performance in distinguishing coffee aromas from different plantations, highlighting its potential for applications in coffee quality control and aroma analysis. The PPy/GO composite was synthesized using a proven method and characterized using Fourier transform infrared spectroscopy (FTIR). Fabrication of the sensor involved a straightforward drop-coating technique that allowed precise control of film thickness. Susceptibility testing was performed under controlled conditions using coffee vapor at various concentrations. To evaluate the performance of the sensor in real-world scenarios, coffee samples from three different plantations were analyzed. Despite minor variations in sensor response due to inherent differences in coffee aroma profiles, the overall reproducibility and consistency of the measurements were extremely satisfactory. The %RSD values between 1.11% and 4.75% demonstrate the precision and reliability of the sensor. Keywords: Graphena Oxide, Polypirrole, gas sensor, coffee aroma, thickness optimization

Abstract: Water sources in coastal areas are highly susceptible to seawater intrusion, leading to significant environmental and economic losses. Therefore, advanced treatment methods are required to make seawater suitable for clean water production, particularly in addressing water scarcity in coastal regions. One promising approach is seawater desalination using calcium alginate/graphene oxide (GO) beads. In this study, waste coral skeletons were utilized as a calcium source due to their high calcium content. X-ray fluorescence (XRF) analysis revealed that the calcium content in the coral skeletons was 93.4% before calcination and increased to 94.9% after calcination. These findings suggest that coral skeleton waste has potential as an adsorbent for Na⁺ and Cl⁻ ion removal. The synthesis of calcium alginate/GO was conducted using a droplet method and characterized using Fourier-transform infrared spectroscopy (FTIR). The adsorption process for Na⁺ and Cl⁻ ions was investigated at varying CaCl₂ concentrations (0.5 M, 1 M, and 2 M) to determine the optimal conditions for ion removal. Na⁺ ion analysis was performed using atomic absorption spectroscopy (AAS), while Cl⁻ ion concentration was determined via argentometric titration. The optimal Cl⁻ adsorption was observed at a CaCl₂ concentration of 0.5 M with a contact time of 30 minutes, achieving an adsorption efficiency of 99.8% in a standard NaCl solution and 35.9% in seawater. For Na⁺ ion removal, the highest adsorption efficiency was achieved at a CaCl₂ concentration of 2 M with a 30-minute contact time, resulting in 97.3% adsorption in a standard NaCl solution and 61.9% in seawater. These results highlight the potential of calcium alginate/GO composites, derived from waste coral skeletons, as effective adsorbents for seawater desalination.

Abstract: This paper presents effect of low contents graphene oxide (GO) on the properties of cement mortar that could be developed for nano modification in cement composites. The characteristic of GO-cement mortars were first evaluated using slump flow test. Then, mechanical properties of GO-cement mortars were carried out. Specimens were made on a 5×5×5 cm³ cube mold with five different contents of GO (e.g., 0.01% to 0.05 %) using a water to cement (w/c) ratio of 0.485. The compressive strength tests were performed at specimen age of 3, 7, and 28 days. Results showed that the incorporation of GO significantly improved mechanical properties of GO-cement mortars. Further, the obtained compressive strength of mortars significantly increased and achieved the highest 28 day-strength by 63.6% at 0.04% GO.

Abstract: The current reliance on non-biodegradable plastic packages poses environmental and health hazards from their indiscriminate disposal. This study attempts to fabricate environmentally friendly cellulose nanofibers (CNFs) and carbon dot (HCDs) nanocomposite film from thatching grass waste for potential use in the food packaging industry. CNFs were extracted from Hyparrhenia hirta grass through a series of chemical pretreatments and sulphuric acid hydrolysis, and the carbon dots were synthesized from the extracted nanofibers via solvothermal treatment. The properties of the CNFs and carbon dots were studied using standard scientific techniques, including Fourier transform infrared (FT-IR), Scanning electron microscopy, Raman spectroscopy. The mechanical and water resistance properties of the CNFs/HCDs films were also determined. The results indicate that it is possible to fabricate a flexible and elastic CNFs/HCDs film suitable for packaging applications. The water contact angle measurement for the CNFs/HCDs films also revealed that the surface of the films was hydrophobic, making them suitable for packing dry foods and potentially electronics. Future studies will focus on optimizing the CNFs/HCDs ratio in the chitosan matrix, as the most promising ratio identified so far is 80:20 (film F2).

Abstract: This study focuses on developing a composite material using graphene oxide (GO) as a dielectric film. First, GO was mixed with DI water and dried to form a film. Then, a titanium (Ti) film was deposited on the film surface through electron beam evaporation. The composite comprising graphene oxide with the Ti metal film was then dispersed in water, to which cellulose nanofiber (CNF)—noted for its high mechanical strength, stability, and lightweight attributes—was added. The mixture was then re-layered with cellulose nanofibers by agitating it in water, and subsequently dried to form a composite film. The electrical properties of the material were studied using an LCR meter. The results show that pure GO has a dielectric constant of about 1600 at 1 kHz and a dielectric loss of about 25. After adding Ti, the Ti composite film maintained a dielectric constant above 1000 at 1 kHz while significantly reducing the dielectric loss to 1.5. Additionally, the resistivity of pure GO at 1 kHz is approximately 1200 Ω·m, whereas the Ti composite film with Ti and cellulose nanofibers shows a resistivity as high as 50 k Ω·m at 1 kHz. The relationship between dielectric strength and resistivity indicates that the Ti composite film can withstand higher voltages compared to pure GO, demonstrating a significant increase in dielectric strength. Compared to graphene oxide, the Ti composite film combines high dielectric constant, low dielectric loss, and increased dielectric strength.

Abstract: When discussing graphene materials, their mechanical strength, impermeability, flexibility, thermal and electrical conductivity, and lightness are key reference points, earning them the moniker "all-in-one material. “This versatility makes graphene suitable for various applications, including electronics, medicine, plastics, coatings, construction, and renewable energies. However, it's crucial to note that the behavior of these materials at the nanometric scale depends on factors such as the type of graphene, functionalization, concentration, and the specific processes involved in each industry. Since the isolation of graphene in 2004, significant efforts have been made to comprehend its multifunctional properties. Nevertheless, the primary challenge lies in translating this knowledge from the laboratory to industrial applications, hampered by the high cost and low yield of graphene. Fortunately, the construction industry, particularly the concrete and coatings sector, appears to be one of the most promising fields for the integration of this nanotechnology. In this context, we present a diverse array of representative trials conducted on various concrete designs and environmentally friendly, antimicrobial, and anticorrosive coatings enhanced with graphene materials. These trials showcase the multifunctional enhancement of properties thanks to the incorporation of graphene materials in different commercially available products tailored for industrial applications, demonstrating that graphene not only represents a technological innovation but is also a catalyst for more sustainable practices in various industries. Its ability to improve the efficiency of different products and applications, becomes graphene as a key material in the immediate future with which industries operate within ecological limits while meeting human needs.