Modified Graphene Oxide Research Articles

Hexagonal Morphology Nickel Sulfide Anchored on Graphene Oxide–Modified Glassy Carbon Electrode for the Sensitive Detection of Paracetamol in Biological Samples

Hexagonal Morphology Nickel Sulfide Anchored on Graphene Oxide–Modified Glassy Carbon Electrode for the Sensitive Detection of Paracetamol in Biological Samples

Extraction of methamphetamine and pseudoephedrine by modified graphene oxide solid phase extraction method coupled to HPLC-UV in urine sample.

Methamphetamine, pseudoephedrine, and related drugs are among the first drugs used for the stimulation of the central nervous system. In this study, two adsorbents based on graphene oxide (GO) were synthesized and used for the analysis of methamphetamine and pseudoephedrine. The prepared nano-adsorbents based on GO in this study were coated by polyaniline (PANI) and Fe3O4/C-nanodot/GO (magnetic adsorbent). The average size of nanoparticles (GO/PANI) was 18.43nm. The specific surface area and pore size diameter of Fe3O4/C-nanodot/GO were 22.71 m2 g- 1 and 15.23nm, respectively. Experimental variables affecting the extraction efficiency of the analytes such as pH of the sample solution, amount of adsorbent, extraction time, and type of eluents were investigated and optimized by response surface methodology. Under optimum conditions, GO/PANI and Fe3O4/C-nanodot/GO were considered appropriate solid phase extraction adsorbents for HPLC-based analyses of the studied drugs in human urine samples. However, GO/Fe3O4 nano adsorbent (Fe3O4/C-nanodot/GO) showed superior working condition than GO/PANI. The validated proposed analytical methods can be used for the quantitative determination of methamphetamine and pseudoephedrine in actual samples.

Influence of the graphene oxide-coated steel fiber on the microstructure optimization of UHPC

Benefiting from its superior mechanical properties, large specific surface area and abundant oxygen-containing functional groups, graphene oxide (GO) can generate nucleation and pore-infilling effects to optimize the microstructure of the cementitious composites, thus reinforcing the mechanical performance and durability of cement-based materials. However, due to the dispersion issues and relatively high cost, the widespread use of GO in the cement industry has not yet been realized. In the present study, we applied three different methods to coat industrial GO nanosheets on the steel fiber’s surface and reinforce the UHPC microstructure. The proposed coating method effectively disperses GO within the ultra-high-performance concrete (UHPC) matrix and targets its enhancement effects on the interfacial transition zone (ITZ), which has the weakest pore structure in UHPC. The result presents that the three-step dip method of GO coating on the steel fiber demonstrates higher effectiveness in reinforcing the microstructure of UHPC, the porosity of the matrix is 1.88 %, with a relative decrease of 37.1 ∼ 60.3 %. In addition, the average distance of ITZ after GO enhanced UHPC is about 3.7 µm, about 37.3 %-68.1 % shorter, and the ITZ porosity is 3.8 %, which is 15.6 %-65.5 % lower. With the assistance of the metal intrusion technique, backscattered electron characterization and deep learning-based analysis, the pore structure features of UHPC were extracted with a classification recognition accuracy of 88.5 %, and the pore intrusion volume inside the characteristic region of the UHPC matrix increased by 1.89–2.14 times. The extraction characteristics illustrated that the GO strengthening on steel fibers was more effective in ITZ, with an optimization efficiency of about 8.1 % higher than in other regions. We expect that the findings of this study could provide deep insights into GO modification for cementitious composite reinforcement applications and open new pathways for affordable alternatives to nano-enhanced composites.

Nanosilver and Graphene Oxide Modified Screen-Printed Carbon Electrode for Electrochemical Detection of Bisphenol A

Nanosilver and Graphene Oxide Modified Screen-Printed Carbon Electrode for Electrochemical Detection of Bisphenol A

Surface Modification of Graphene Oxide and Its Strengthening and Toughening Mechanism for Alumina-Based Ceramic Materials

Surface Modification of Graphene Oxide and Its Strengthening and Toughening Mechanism for Alumina-Based Ceramic Materials

Mitigating Membrane Fouling in Abattoir Wastewater Treatment: Integration of Pretreatment Step with Zwitterion Modified Graphene Oxide–Polyethersulfone Composite Membranes

Composite polyethersulfone (PES) membranes containing N-aminoethyl piperazine propane sulfonate (AEPPS)-modified graphene oxide (GO) were integrated with either of the two pretreatment processes (activated carbon (AC) adsorption or polyelectrolyte coagulation) to assess their effectiveness in mitigating membrane fouling during the treatment of abattoir wastewater. The AEPPS@GO-modified membranes, as compared to the pristine PES membranes, showed improved hydrophilicity, with water uptake increasing from 72 to 118%, surface porosity increasing from 2.34 to 27%, and pure water flux (PWF) increasing from 235 to 673 L.m−2h−1. The modified membranes presented improved antifouling properties, with the flux recovery ratio (FRR) increasing from 59.5 to 93.3%. This study compared the effectiveness of the two pretreatment processes, AC, coagulation, and the integrated system (coagulation/AC-UF membrane), in the removal of natural organic matter (NOM) and improvement of abattoir wastewater’s pH, electrical conductivity, TDS, and turbidity. The integrated systems produced improved water quality in terms of pH, EC, TDS, turbidity, and organic content. The fluorescence excitation–emission matrix (FEEM) analysis exhibited almost no fluorescence peak post-treatment following organic loading removal. The quality of the water met the South African non-potable water reuse standards. The sole membrane treatment systems exhibited good fouling resistance without the pretreatment systems; however, integrating these systems can offer extended longer filtration periods, thereby assisting in cost aspects of the abattoir wastewater treatment system.

Alginate-modified graphene oxide anchored with lactoperoxidase as a novel bioactive nanocombination for colorectal cancer therapy

It is imperative to explore new biocompatible drugs with low toxicity for use in medicinal fields such as fighting tumors. Bovine lactoperoxidase (BLPO) stems from the most important enzymes in the bovine whey that provide a proper pattern for nano-formulation with nanomaterials. LPO is a suitable protein to be coated or adsorbed to alginate modified graphene oxide (GO-SA), which forms the modified GO-SA-LPO hybrid structure. This novel combination provides LPO stability with strong anticancer effects and boosts immunity response. The characterization results obtained from different techniques confirmed a successful LPO adsorption on the GO-SA composite surface. Moreover, nano-formulation of LPO with GO-SA composite exhibited a reduction in its size and overall charge. In addition, the experimental results showed greater LPO activity stability in the modified GO-SA-LPO nanocombination than free LPO after storage for 10 weeks at 4 °C. The in vitro study, a crucial step in the validation of our approach, demonstrated that the modified GO-SA-LPO nanocombination showed a potent anticancer selectivity toward colon cancer cell lines more than GO-SA composite or free form of LPO, which enhanced in a dose-dependent manner with high safety manner against normal cells. The apoptotic effect of this novel nanocombination was confirmed by the greatest variations in the expression of both well-known apoptosis genes (p53 and Bcl-2), severe changes in the cellular morphology, DNA fragmentation, and nuclear staining with fluorescence yellow and orange of the target cancer cells. Also, this superior efficacy of the modified GO-SA-LPO nanocombination was induced by suppressing some pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin (IL-6), and necrosis factor-kappa B (NF-ĸB). Our observations presented that the modified nanocombination of LPO may offer a novel remedy for treating colon tumors via induced apoptosis pathway, inflammation reduction, and immune response improvement.

Removal of Ibuprofen from Aqueous Solutions by Using Graphene Oxide@MgO

In this study, a new composite adsorbent, namely magnesium oxide modified graphene oxide (hereafter abbreviated GO@MgO), was prepared for the removal of Ibuprofen (IBU), a non-steroidal anti-inflammatory drug (NSAID) compound. Graphene oxide was modified with MgO to improve its properties. Several factors important for the evolution of the adsorption process were investigated, such as the dose of the adsorbent, the pH, and the initial IBU content, as well as the duration of the procedure and temperature. According to the results obtained, it was found that at pH 3.0 ± 0.1, by applying 0.5 g/L GO@MgO to 100 mg/L IBU, more than 80% was removed, reaching 96.3% with the addition of 1.5 g/L adsorbent in 24 h. After 30 min, the equilibrium was reached (77% removal) by adding 0.5 g/L of GO@MgO. This study proves that GO@MgO is capable of economical and efficient adsorption. The IBU kinetic data followed the pseudo-second-order kinetic model. Langmuir and Freundlich isotherm models were used to interpret the adsorption, but the Freundlich model described the adsorption method more accurately. The positive values of ΔH0 (14.465 kJ/mol) confirm the endothermic nature of the adsorption. Due to the increase of ΔG0 values with temperature, the adsorption of IBU on GO@MgO is considered to be spontaneous.

Functionally Modified Graphene Oxide as an Alternative Nanovehicle for Enhanced dsRNA Delivery in Improving RNAi-Based Insect Pest Control.

RNA interference (RNAi) has shown substantial promise as a sustainable pest management solution. However, the efficacy of RNAi-based insecticides heavily relies on advanced nanocarrier-mediated delivery systems. In this study, we modified raw graphene oxide into positively charged nanocarriers (GONs) tailored to bind with double-stranded RNA (dsRNA). The resulting GONs@dsRNA complexes demonstrated a small particle size (106 nm) and maintained stability under various conditions, including insect gut extracts, extreme pH, and extreme temperature. Furthermore, GONs efficiently transported dsRNA molecules into Drosophila S2 cells and Lepidoptera Sf9 cells, leading to an enhanced target transcript knockdown. Targeting the vacuolar ATPase gene, vha26, induced significant mortality and target transcript knockdown in D. suzukii adults but not in S. exigua. Finally, GONs@dsRNA complexes exhibited negligible cytotoxicity at both the cellular and organismal levels. This study demonstrates the potential of GONs as a biosafe nanovehicle for efficient dsRNA delivery into insects, presenting an alternative strategy for advancing RNAi applications in fundamental studies and pest control.

5-Fluorouracil adsorption on graphene oxide-amine modified graphene oxide/hydroxyapatite composite for drug delivery applications: Optimization and release kinetics studies

The present study focused on investigation of graphene oxide/hydroxyapatite (GO/HAp) and amine modified graphene oxide/hydroxyapatite (GO-NH2/HAp) composites as potential drug carrier agents for 5-Fluorouracil (5-FU). Incorporation of 5-Fluorouracil drug was performed via adsorption through π-π interactions and electrostatic attractions. Modification of graphene oxide was performed for the production of amine modified graphene oxide/hydroxyapatite composite with the intention of enhancing adsorption performance. The X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and zeta potential/particle size analysis were performed for particle characterization while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis were used to analyze detailed morphological properties. Experimental design studies were followed out in order to determine the effect of adsorption parameters including graphene oxide amount, pH and initial drug concentration on 5-Fluorouracil adsorption behavior. Adsorption isotherms of both composites with unmodified and modified GO were best fitted to Freundlich model with R2 values of 0.9616 and 0.9682 respectively. The maximum adsorption capacities (qm) were calculated as 47.3 mg/g and 18.4 for graphene oxide/hydroxyapatite and amine modified graphene oxide/hydroxyapatite composites respectively at pH 2.0. The highest adsorption percentage was obtained for amine modified graphene oxide/hydroxyapatite composite as 40.87 % at pH 2.0 condition. In vitro release kinetic studies revealed that compliance with Higuchi and Korsmeyer-Peppas kinetic models were observed for graphene oxide/hydroxyapatite, whereas zero order and Korsmeyer-Peppas kinetic models pointed out as the well-fitted model for amine modified graphene oxide/hydroxyapatite composite. The release period of 5-FU drug from all composites were continued up to 8–10 h in physiological conditions (pH 7.4, 37 °C) indicating an achieved controlled release. Based on the overall findings, graphene oxide/hydroxyapatite and amine modified graphene oxide/hydroxyapatite composites could be suggested as a potential drug delivery agent for 5-FU in clinical applications.

Low-energy argon ion beam irradiation for the surface modification and reduction of graphene oxide: Insights from XPS

Developing environmentally friendly methods for reducing graphene oxide (GO) is essential. This study investigates the surface modification and reduction of GO films using 200 eV argon ion (Ar+) beam irradiation. X-ray Photoelectron Spectroscopy (XPS) analysis reveals significant chemical changes on the GO surface. GO was irradiated with a 200 eV Ar+beam for varying times (0–80 s). XPS survey spectra showed the presence of carbon and oxygen, with an increasing carbon atomic percentage over time. High-resolution XPS spectra of C 1s revealed peaks corresponding to sp2, C–OH, O–C–O, CO, and O–CO bonds. In the O 1s spectra, CO, O–C–O, and C–OH groups were observed. Upon irradiation, the CO peak consistently decreased, the O–C–O peak fluctuated, and the C–OH peak increased, indicating effective reduction of CO groups, dynamic changes in O–C–O functionalities, and the formation of additional C–OH groups. The C/O ratio increased from ∼2.4 to 2.7, underscoring the reduction process and enhanced carbon content. This method proves to be an efficient approach for producing reduced graphene oxide (rGO) with improved properties for advanced applications.

Simultaneous detection of CaMV35S and NOS using fluorescence sensors with dual-emission silver nanoclusters and catalytic hairpin amplification strategy.

Adual-emission fluorescent biosensing method was developed for simultaneous determinationof CaMV35S and NOS in genetically modified(GM) plants. Two designed hairpin DNA (H1, H2) sequences were used as templates to synthesize H1-AgNCs (λex = 570nm, λem = 625nm) and H2-AgNCs (λex = 470nm, λem = 555nm). By using H1-AgNCs and H2-AgNCs as dual-signal tags, combined with signal amplification strategy of magnetic separation to reduce background signal and an enzyme-free catalytic hairpin assembly (CHA) signal amplification strategy, a novel multi-target fluorescent biosensor was fabricated to detect multiple targets based on FRET between signal tags (donors) and magnetic Fe3O4 modified graphene oxide (Fe3O4@GO, acceptors). In the presence of the target NOS and CaMV35S, the hairpin structures of H1 and H2 can be opened respectively, and the exposed sequences will hybridize with the G-rich hairpin sequences HP1 and HP2 respectively, displacing the target sequences to participate in the next round of CHA cycle. Meanwhile, H1-HP1 and H2-HP2 double-stranded DNA sequences (dsDNA) were formed, resulting in the desorption of dsDNA from the surface of Fe3O4@GO due to weak π-π interaction between dsDNA and Fe3O4@GO and leading to the fluorescence recovery of AgNCs. Under optimal conditions, the linear ranges of this fluorescence sensor were 5 ~ 300nmol L-1 for NOS and 5 ~ 200nmol L-1 CaMV35S, and the LODs were 0.14nmol L-1 and 0.18nmol L-1, respectively. In addition, the fluorescence sensor has good selectivity for the detection of NOS and CaMV35S in GM soybean samples, showing the potential applications in GM screening.

Application of bio-based modified graphene oxide in epoxy composite coatings

This study focuses on the application of bio-based modified graphene oxide epoxy composite coatings and analyzes the coating properties, such as anticorrosive ability, hydrophobicity and self-healing properties, through experimental studies of modified graphene oxide using substances such as cashew nut phenol, lignin and glutamic acid. Summarizing the latest research progress, it is found that the materials such as cardanol, lignin and glutamic acid are from a wide range of sources, are green and have a wide range of application prospects, and it is also shown in the results of EIS analysis that the modified graphene oxide epoxy compliant coatings exhibit higher impedance values at low frequencies, and have good protective properties and barrier properties. The cashew phenol-modified graphene oxide epoxy coating has high densification, high barrier capacity and high hydrophobicity in addition to good coating healing ability using GO modification. The glutamate-modified graphene oxide epoxy coating can be desorbed by using HCL solution to make L-Glu/GO reusable, with good reusability and high application value.

Evaluation of the performance enhancement of asphalt concrete via graphene oxide incorporation: A multi-test approach

The need for improved asphalt pavements has led to the exploration of nanomaterials such as graphene oxide (GO). This study investigates the potential of GO to enhance the performance of asphalt concrete (AC) with a nominal maximum aggregate size of 12.5 mm (AC_12.5) pavements, a commonly used material in highway construction that has not been extensively studied with GO modification. The main objective is to evaluate the impact of varying GO content (1%, 1.5%, and 2%) on the key technical properties of AC_12.5, including rutting resistance, moisture stability, and tensile capacity. A series of performance tests, including Marshall stability, residual stability, splitting tensile strength, and dynamic modulus, were conducted on AC_12.5 samples with varying GO content. Furthermore, a mechanistic– empirical (M-E) approach was employed to compare the rutting resistance of GO-modified pavements with that of conventional pavements. Initial findings suggest that GO incorporation significantly enhanced the mechanical properties of AC_12.5 compared with the control mixture. Performance tests indicated improved rutting resistance, moisture stability, and tensile capacity. The M– E analysis demonstrated superior rutting resistance in the GO-modified pavement structures. The findings confirm the potential of GO as a promising nanomaterial for enhancing the performance of AC_12.5 pavements. The observed improvements in key mechanical properties and rutting resistance suggest its feasibility for developing more durable, sustainable, and cost-effective roads in the future.

Surface one-step modification of graphene oxide with N-cyclohexylbenzothiazole-2-sulfonamide to enhance the wear resistance of natural rubber/butadiene rubber composites

Natural rubber (NR) and butadiene rubber (BR) composites are frequently used in manufacturing tires and conveyor belts, which are susceptible to severe wear, leading to product failure and significant losses. To enhance the wear resistance of NR/BR composites, we prepared NR/BR composites reinforced with a synergy of N-cyclohexylbenzothiazole-2-sulfonamide surface one-step modified reduced graphene oxide (CZ-rGO) and carbon black N234 (CB) using a latex co-precipitation method. This study explored the effects of GO content and CZ modification on the structure, wear resistance, thermal conductivity, and mechanical properties of the NR/BR blended composites. It showed that adding 2 phr of GO resulted in excellent filler dispersion, significantly improving the tensile strength, elongation at break, tear strength, thermal conductivity, and wear resistance of the composites. The incorporation of CZ-rGO further increased the crosslinking density, vulcanization performance, and filler dispersion with enhanced mechanical properties, thermal conductivity, and wear resistance of the composites. Notably, the DIN abrasion volume was reduced to 77.88 mm³, surpassing the ISO 10247 standard for conveyor belt cover rubber in terms of wear resistance. The wear resistance of NR/BR/CZ-rGO composites is not only significantly higher than that of single NR- or SBR-based rubber composites, but also significantly higher than that of other binary rubber blend composites, and the CZ-rGO filler is simpler in composition and structure and exhibits a more prominent wear enhancement. This work provides guidance for an efficient and environmentally friendly approach to GO surface modification, as well as useful insights for the development of high wear-resistant rubber composites with excellent overall performance.

Preparation and Characterization of Epoxy-Based Composite Materials Reinforced with Graphene Oxide

In this study, modified graphene oxide (GO) with γ-APS silane coupling agent before being dispersed into an epoxy/4,4’-diamino diphenyl methane matrix to prepare a composite material using the bar-coating technique. The modified GO materials with the γ-APS silane (GOS) were characterized by infrared spectrum, Zeta potential, and TG/DSC thermal analysis. The amount of silane grafted on the GO is ~ 3.3 wt.%; the Zeta potential value shifted from the negative to the positive region was observed on the surface potential distribution diagram. Scanning electron microscopy, DSC thermal analysis, and dielectric constant were used to characterize the obtained composite epoxy/GO material properties. The results show that graphene oxide, after modification with γ-APS silane agent, has good dispersion ability in the epoxy resin matrix. Composite material epoxy/GOS presented a high dielectric constant value (εaverage = 6.19, at 1 kHz), increasing thermal stability, which is a suitable material promising for future applications.

Improving shale hydration inhibition with hydrophobically modified graphene oxide in water-based drilling fluids

Frequent wellbore instability issues caused by shale hydration and dispersion are encountered in water-based drilling fluids. In order to mitigate shale hydration, a hydrophobic graphene oxide (HGO) was prepared as a new shale inhibitor and characterized. The effectiveness of HGO in inhibiting shale hydration was evaluated through hydration expansion, hydration dispersion, and bentonite sheets immersion tests. The expansion height of bentonite in HGO (3.87 mm) was lower than that of commercial shale inhibitors potassium chloride (KCl, 4.64 mm) and polyether amine (PA, 4.33 mm). The shale recovery rate in HGO at 80 °C was 86.25 %, which was superior to KCl (46.60 %) and PA (78.25 %). Furthermore, the morphology of bentonite sheet remained more intact after immersion in HGO. Additionally, the inhibitory mechanism of HGO was studied in-depth, employing zeta potential, particle size, surface tension, wettability, capillary rise height, and scanning electron microscopy (SEM) tests. By virtue of electrostatic attraction, HGO could tightly adsorb to the shale surface, resulting in a hydrophobic blocking membrane, thereby greatly reducing water infiltration. Following interaction with shale at a concentration as low as 0.5 %, the water contact angle exhibited a notable enhancement, rising from 22.49° to 86.69°. And it could also decrease the capillary self-suction capacity of shale, further reducing water adsorption. Consequently, HGO exhibited significant potential for inhibiting hydration in shale drilling.

Bismuth molybdate nanoparticles modified graphene oxide: A novel nanocomposite for photocatalytic removal of organic dyes

Utilization of solar energy for the degradation of organic pollutants is a promising sustainable approach. Here in this research work, bismuth molybdate (Bi2MoO6) nanoparticles (NPs) modified graphene oxide sheets (Bi2MoO6@GO) were employed as efficient photocatalysts for the removal of organic dyes under illuminated sunlight. The synthesized nanocomposite was subjected to characterization via XRD, FTIR, Raman, SEM, EDX and UV–Vis spectroscopic analysis. The photocatalytic efficiency of fabricated nanocomposite (Bi2MoO6@GO) has been studied against organic pollutants including rhodamine B and methylene blue in aqueous solution under direct sunlight irradiation. Bi2MoO6 decorated graphene oxide nano-photocatalyst exhibited 91 % and 88 % degradation of methylene blue and rhodamine B within ∼ 70 min with apparent rate constant values of 0.0323 and 0.0246 min−1, respectively. The study showed that fabricated photocatalyst (Bi2MoO6@GO) possesses a comparatively low band gap, heterogeneous morphology and boosted active surface area which makes it an efficient photocatalyst for the effective remediation of organic pollutants.

Construction and properties of graphene oxide hydrogen-blocking coatings

Compared with the composite coating with a single structure, the coating with a multilayer structure may possess better hydrogen barrier performance. Graphene oxide (GO) was chemically modified using polyethylene glycol diglycidyl ether (EGDE) to obtain modified graphene oxide (mGO). The introduction of epoxy groups in mGO would participate in the crosslinking reaction between the epoxy resin (EP) emulsion and the curing agent to improve the dispersion and adhesion of the middle layer in the sandwich structure. An EP/mGO/EP composite coating with a sandwich structure was prepared. The research found that the tightly stacked mGO middle layer in the sandwich structure played a crucial role. The average adhesion of the multilayer composite coating was about 9 MPa. The electrochemical impedance spectroscopy of layer 2-mGO composite coating showed that its modulus was up to 109 Ω cm2. The permeation current density ip and hydrogen content remained at low values of 1.38 μA and 1.34 ppm, respectively. The multilayer composite coating possessed not only excellent adhesion but also excellent corrosion resistance and hydrogen barrier performance.

Hydrophobically modified GO integrated PAN nanofibrous membranes for separation of water-in-oil emulsions

Nanofibrous membranes with super-wetting feature exhibit promising application for oil/water emulsion separation, but achieving high separation efficiency in harsh environments remains challenging. Herein, superhydrophobic/superoleophilic nanofibrous membrane based on polyacrylonitrile (PAN) and hydrophobically modified graphene oxide (GO) was prepared by electrospinning technique. The multidimensional roughness that was produced by the overlapping of modified GO and nanofibers was crucial in producing superhydrophobic and superoleophilic wettability. For a variety of water-in-oil emulsions, the obtained nanofibrous membranes demonstrated outstanding oil/water separation performance. The maximum permeate flux reached 5135.8 L·m−2·h−1 with separation efficiency higher than 99.1 %. More importantly, the obtained nanofibrous membranes showed stable separation performance in strongly corrosive solutions or at high temperatures. This work presents a versatile way to fabricate functional membranes for the separation of water-in-oil emulsions.