Incorporation Of Graphene Oxide Research Articles

Biodegradable composite from discarded hair keratin and graphene oxide with improved mechanical, thermal and barrier properties: an eco‐friendly solution to waste materials

AbstractIn recent years, there has been a growing concern to counter environmental pollution, and as a result the development of biodegradable materials in various applications has become a major focus. This study aimed to fabricate a biodegradable composite by utilizing discarded hair keratin from beamhouse processing in leather production along with incorporating graphene oxide (GO) to reduce pollution. The composite was prepared using a simple solution mixing method, where the amino functional group of keratin and the carboxyl group of GO were covalently bonded under a redox system. Various analyses, including UV–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, SEM, biodegradability and oxygen gas transmittance rate, were carried out to evaluate the composite's structure and performance. The results demonstrated that GO was successfully integrated into the keratin matrix, with uniform dispersion of GO observed instead of agglomeration. The composite with the optimum ratio exhibited a 173.98% increase in tensile strength and a 33.52% decrease in elongation as well as improved thermal and biodegradation properties compared to pure keratin. Furthermore, the composite displayed significantly better gas barrier properties (39%) than pure keratin, which can be attributed to the reduction of intermolecular gaps through the composite's strong bonding. Hence, the keratin‐GO composite is a cost‐effective and biodegradable solution to waste materials, with potential use as a packaging material. © 2023 Society of Chemical Industry.

Graphene oxide quantum dots membrane: a hybrid filtration-advanced technology system to enhance process of wastewater reclamation

The inability of wastewater treatment plants to effectively remove emerging pollutants has necessitated the need to develop newer advanced technologies. An integrated approach of combining advanced oxidation processes (AOPs) and membrane technologies promises superior performances. In this study, graphene oxide quantum dots-based membranes (GQDs-Ms) were fabricated via the phase inversion method. The GQDs-Ms revealed high oxygen content and a negative surface charge. The incorporating graphene oxide quantum dots (GQDs) into the polymer matrix led to enhanced hydrophilicity, pore size, porosity, improved flux as well as superior inhibition of Escherichia coli cells. A multi-AOPs approach was used in this work, wherein AOPs were applied as both pre-treatment (using GQDs) and post-treatment (combining GQDs with peracetic acid) in the disinfection of wastewater. The evaluation of GQDs-Ms performance was carried out and compared with a commercial membrane (Film Tec™NF270). The obtained % removals with GQDs-Ms were 83.45%, 64.12%, 40.76% and 70.36% for turbidity, total dissolved solids, total organic carbon and electrical conductivity, respectively, which compared nearly with commercial membrane’s performance. Interestingly, the integrated hybrid system can further remove and inactivate microbes in wastewater. The developed hybrid filtration-advanced technology system can substantially improve conventional wastewater treatment plants for water reuse.

Adsorptive Membranes Incorporating Ionic Liquids (ILs), Deep Eutectic Solvents (DESs) or Graphene Oxide (GO) for Metal Salts Extraction from Aqueous Feed.

Water scarcity is a significant concern, particularly in arid regions, due to the rapid growth in population, industrialization, and climate change. Seawater desalination has emerged as a conventional and reliable solution for obtaining potable water. However, conventional membrane-based seawater desalination has drawbacks, such as high energy consumption resulting from a high-pressure requirement, as well as operational challenges like membrane fouling and high costs. To overcome these limitations, it is crucial to enhance the performance of membranes by increasing their efficiency, selectivity, and reducing energy consumption and footprint. Adsorptive membranes, which integrate adsorption and membrane technologies, offer a promising approach to address the drawbacks of standalone membranes. By incorporating specific materials into the membrane matrix, composite membranes have demonstrated improved permeability, selectivity, and reduced pressure requirements, all while maintaining effective pollutant rejection. Researchers have explored different adsorbents, including emerging materials such as ionic liquids (ILs), deep eutectic solvents (DESs), and graphene oxide (GO), for embedding into membranes and utilizing them in various applications. This paper aims to discuss the existing challenges in the desalination process and focus on how these materials can help overcome these challenges. It will also provide a comprehensive review of studies that have reported the successful incorporation of ILs, DESs, and GO into membranes to fabricate adsorptive membranes for desalination. Additionally, the paper will highlight both the current and anticipated challenges in this field, as well as present prospects, and provide recommendations for further advancements.

Effect of silver nanoparticles on the morphological, antibacterial activity and performance of graphene oxide-embedded polyvinylidene fluoride membrane

In this work, a different ratio of silver nanoparticles (Ag NPs) was used as a nanofiller on graphene oxide (GO)-embedded polyvinylidene fluoride (PVDF) membranes fabrication through a non-solvent induced phase separation method. The morphology of fabricated membranes was investigated using FTIR, XRD, and SEM-EDX techniques. The fabricated membranes were tested for Bovine Serum Albumin (BSA) rejection and Molecular Weight Cut Off (MWCO) with various initial concentrations of 100 – 400 ppm and 6 – 145 kDa, respectively using a crossflow method, as well as antibacterial activity against four strains bacteria via total plate counting and Kirby-Bauer method. The incorporation of hydrophilic GO and Ag NPs obviously alters membrane morphology, enhances membrane’s porosity and hydrophilicity. Moreover, it improves membrane crystallinity (> 70%) as indicated by the higher XRD peaks intensity. Based on the crossflow measurements, the membrane fabricated with GO and Ag ratio of 1: 3 (PVDF/GO/AgNPs – 3) demonstrated the highest BSA flux of 83.81 L/m2 h, which was third-fold higher than that of PVDF membrane as well as high BSA rejection (> 94%) and MWCO of ∼3 kDa. According to the observation, PVDF/GO/AgNPs – 3 also possessed a high bacteria killing ratio of > 94% and a large inhibition zone of ≥ 1.5 mm toward all bacteria strains. These results inferred that PVDF/GO/Ag membrane has great potential as antibiofouling membranes.

Degradation of Mechanical Properties of Graphene Oxide Concrete under Sulfate Attack and Freeze-Thaw Cycle Environment.

In this paper, firstly, the effects of graphene oxide on the mechanical properties of concrete were investigated. Secondly, the degradation and mechanism of the mechanical properties of graphene oxide concrete (GOC) under sulfate attack and a freeze-thaw environment were investigated. In addition, the dynamic modulus of elasticity (MOEdy) and uniaxial compressive strength (UCS) of the GOC were measured under different environmental conditions. According to the test results, the incorporation of graphene oxide in appropriate admixtures could improve the mechanical properties of concrete in these two working environments. It is worth noting that this effect is most pronounced when 0.05 wt% graphene oxide is incorporated. In the sulfate attack environment, the MOEdy and UTS of the GOC0.05% specimen at 120 cycles decreased by 22.28% and 24.23%, respectively, compared with the normal concrete specimens. In the freeze-thaw environment, the MOEdy and UTS of the GOC0.05% specimen at 90 cycles decreased by 13.96% and 7.58%, respectively, compared with the normal concrete specimens. The scanning electron microscope (SEM) analysis showed that graphene oxide could adjust the aggregation state of cement hydration products and its own reaction with some cement hydration crystals to form strong covalent bonds, thereby improving and enhancing the microstructure density.

Self-healing nanocomposite hydrogels based on chitosan/ modified polyethylene glycol/graphene

The aim of this research is to prepare self-healing injectable nanocomposite hydrogels based on benzaldehyde-modified polyethylene glycol and chitosan, reinforced with graphene oxide (GO) for the delivery of pomegranate extract (PG) for hard tissue engineering. For this purpose, polyethylene glycol (PEG) was first modified by an aldehyde agent and mixed with chitosan to form hydrogels based on reversible Schiff-Base linkages. Nanocomposites were prepared with the addition of 0.5, 1.0, 1.5, and 2.0 wt% GO to the hydrogels. Then, PG was loaded into the final nanocomposite hydrogels as the drug model to promote cell proliferation and chondrogenesis. The scanning electron microscopy (SEM) images indicated that the incorporation of GO into the hydrogels increased the average pore size from 261 to 403 µm, resulting in a favorable porous structure. The results also showed an enhancement in the elastic properties as well as the compressive strength of the nanocomposite hydrogels with increasing GO content. The drug release profile followed a power-law kinetics, in which, the content of PG and GO affected the release rate. According to self-healing and injection tests, all the hydrogels had good injection and self-healing capabilities. The incorporation of GO into the hydrogel increased antibacterial properties to more than 99%. The in vitro assay indicated that PG loading provided a suitable environment for the growth and survival of cells on the hydrogels. Therefore, the designed system is a promising framework for the local delivery of pharmaceuticals for hard tissue engineering.

Improving mechanical properties and microstructure of ultra-high-performance lightweight concrete via graphene oxide

This paper aims to use lightweight aggregates to design ultra-high-performance lightweight concrete (UHPLC) via modified Andreasen and Andersen (MAA) model, which is promising to solve the issues on the high density of ultra-high-performance concrete and thus benefits its application in high-rise and long-span structures. To reduce the deadweight of ultra-high-performance concrete, UHPLC was prepared by lightweight aggregates, and its initial mixture was designed according to the MAA model in this study. To improve the mechanical properties and microstructure of UHPLC, the UHPLC developed in this work was modified via the incorporation of graphene oxide (GO). In addition, the micro-mechanical properties of UHPLC paste with/without GO were characterized via nanoindentation technique. Results showed that: (1) Due to the incorporation of GO, the flexural strength, compressive strength and elastic modulus of UHPLC increased by 7.1%–17.7%, 4.4%–21.9%, 4.1%–12.9%, respectively; (2) addition of GO led to a significant enhancement in the internal pore structure of UHPLC; (3) From the perspective of the mechanical properties and microstructure of UHPLC, the optimal content of GO was 0.06 wt%. The findings of this work can offer valuable insights for the fabrication of UHPLC.

Hybrid epoxy-SiO2/GO nanosheets anti-corrosive coating for aeronautic aluminum Al6061-T5

AbstractThe mechanical and anti-corrosive evaluation of a hybrid epoxy resin–SiO2 and graphene oxide (GO) are presented. Three composite materials were prepared with 0%, 0.1 wt% and 0.5 wt% GO concentrations. The hybrid material was prepared by the sol-gel process incorporating the silica particles in situ within the epoxy resin (ER) matrix and previously that ER was functionalized with carboxyl groups using abietic acid and labeled as functionalized epoxy resin. The deposition of the three hybrids in aluminum 6061 substrates was made by blade coating, measuring wet and dry film thickness. The study of mechanical properties involved adhesion, pencil scratch hardness, and abrasion test methods where the incorporation of 0.5 wt% of GO improved the mechanical properties considerably. The anti-corrosive properties of the coatings were evaluated through electrochemical impedance spectroscopy and accelerated corrosion using a salt spray chamber showing that GO forms an anti-corrosive barrier increasing the operation life of the coatings in corrosive environments. Anti-ice properties were related to the contact angle measurement from which the GO concentrations showed more hydrophobic behavior. All the tests were carried out according to ASTM standards. The incorporation of 0.5% of GO showed a significant improvement in the mechanical and anti-corrosive results, improving corrosion resistance up to 500 h. The abrasion tests had an increase in 35%, its hardness up to 9H, and the wear index improved by 29.14% compared with composites with 0.1 wt% of GO and without GO. The HREF1 and HREF5 materials do present an increase in the contact angle thanks to the incorporation of graphene oxide. The results of electrochemical impedance spectroscopy and the impedance curves show a better behavior for the HREF5 composite due to the difference in resistance over time.

Nanocomposites of soluble soybean polysaccharides with grape skin anthocyanins and graphene oxide as an efficient halochromic smart packaging

In this study, an environmentally-friendly pH-responsive (halochromic) film was introduced based on the composite of soluble soybean polysaccharide (SP), grape skin anthocyanin extract (GE) and graphene oxide (GO) to monitor food freshness/spoilage in terms of smart packaging. GO was firstly synthesized and characterized; then, SP-based film containing 5 wt% GE and the optimum amount of GO (0.5 wt%) was fabricated through the solvent casting method and characterized in terms of physico-mechanical, thermal, microstructural, spectroscopic, release, pH sensitivity and colorimetric properties. Our results revealed that addition of GE into the SP matrix induced pH sensitivity to the film; however, it decreased the mechanical and thermal properties, and increased moisture content (MC) and water vapor permeability (WVP) of the film. The incorporation of GO into the film eliminated the GE-caused weaknesses and improved the mechanical and thermal properties, and also decreased the MC and WVP of the film. Moreover, the SP-GE-GO nanocomposite film represented a distinguishable color variation in response to TVB-N release and pH changes when used as the salmon fish packaging. Generally, the obtained results indicated that the SP-GE-GO film can be considered a promising candidate for halochromic smart food packaging.

The effects of graphene oxide addition on low velocity impact performance of aramid fiber reinforced epoxy composites

AbstractIn this study, the impact of incorporating graphene oxide (GO) nanoparticles into the matrix of aramid fiber reinforced polymer (AFRP) composites was investigated. The GO nanoparticles were dispersed in the AFRP matrix at three different weight percentages: 0.1%, 0.3%, and 0.5%. The fabrication of the GO dispersed AFRP nanocomposites was achieved using the vacuum assisted resin infusion molding (VARIM) method, and the AFRP plates were cut using a water jet. The sectioned specimens of the fabricated nanocomposites were subjected to low velocity impact tests. The effects of introducing GO nanoparticles at different percentages were evaluated by analyzing the contact force, deflection, maximum absorbed energy versus time and contact force versus deflection curves. Finally, the key parameters of low velocity impact, including contact force, deflection, and maximum absorbed energy, were compared for the different fabricated AFRP nanocomposites. Based on the results, the AFRP composite with 0.3 wt.% of GO nanoparticles exhibited the best performance under low velocity impact loading conditions. However, the agglomeration of nanoparticles became a significant challenge when higher percentages of GO nanoparticles were added to the composite structure. The findings highlight the importance of determining the optimal percentage of nano materials for incorporation into composite structures.

Carrageenan-grafted-poly(acrylamide) magnetic nanocomposite modified with graphene oxide for ciprofloxacin removal from polluted water

The κ-carrageenan-grafted-poly(acrylamide)/Fe3O4-GO (κ-car-g-PAAm@Fe3O4-GO) adsorbent was attained in three stages, utilizing grafted poly(acrylamide) (PAAm) onto κ-carrageenan (κ-car) in Fe3O4 and graphene oxide (GO) presence. Various characteristic analyses were carried out to peruse the chemical properties, morphological features, thermal stability, magnetic behavior, and porosity of the prepared nanoadsorbent. According to the results obtained from the analyses, the prepared nanoadsorbent showed superparamagnetic behavior. It rendered a semicrystalline structure by Fe3O4 presence in the amorphous matrix of the κ-car-g-PAAm. The SEM images exhibit well dispersion of the Fe3O4 magnetic nanoparticles (MNPs) and lamellar GO sheets throughout the hydrogel context. Besides, along with the GO incorporation into the structure, the BET surface area (2.361 m2/g), pore volume (0.008 cm3/g), and pore size (137.49 nm) of the κ-car-g-PAAm@Fe3O4-GO nanoadsorbent were higher than κ-car-g-PAAm@Fe3O4. The maximum adsorption capacity (Qmax) at an ambient temperature for CPFX adsorption was 1146.467 mg/g. These adsorption experiments’ data were described by the Freundlich isotherm, and the pseudo-second-order explains the adsorption kinetics well. The retrievability of the prepared nanoadsorbent was studied and indicated that it could be isolated effectively and reused in three consecutive cycles without remarkable adsorption efficiency loss.

Low-cost lead-free perovskite solar cell with graphene oxide as hole transport layer and carbon as back contact

In this work, an innovative design for environmentally benign perovskite solar cells (PSCs) is introduced by incorporating graphene oxide (GO) as the hole transport layer (HTL) and utilizing carbon for the back contact. Eschewing the traditionally used CH3NH3PbI3, which raises environmental concerns due to lead content, the proposed design features the eco-friendly CH3NH3SnI3 as the absorber layer. The strategic inclusion of GO as the HTL amplifies the PSC's operational efficiency, owing to its superior exciton dissociation and charge transport properties, while simultaneously offering an economical fabrication strategy. Together with the carbon back contact, this configuration promises a sustainable and cost-efficient PSC solution. The proposed PSC architecture comprises FTO (window layer)/TiO2 (electron transport layer)/CH3NH3SnI3 (absorber layer)/GO (HTL)/C (back contact). Through rigorous optimization processes – encompassing parameters like layer thicknesses, interfacial defects, and doping levels – a commendable enhancement in PSC's performance metrics is achieved. The resultant design registered a power conversion efficiency (PCE) of 21.40% and a fill factor (FF) of 83.98%. Furthermore, thermal evaluation from 300 K to 400 K revealed the PSC's exceptional thermal resilience, underscoring its suitability for commercial deployment. All simulations and analyses are conducted using the SCAPS-1D software.

Synthesis of porous carbon with low oxygen content from fulvic acid for high voltage organic supercapacitors

The operating voltage of over 3.0 V is a severe challenge for commercial supercapacitors in organic electrolyte, which raises rigorous requirements for the structure and composition characteristics of porous carbon. There are few reports regarding the construction of ultra-high voltage withstanding porous carbon derived from cheap biomass carbon sources. Herein, using cheap and renewable fulvic acid (FA) and graphene oxide (GO) as carbon precursors, the ultra-high withstanding voltage 2D porous carbon nanosheets are synthesized through KOH activation and annealing treatment, assisted by the π-π conjugation and hydrogen bonding. The incorporation of GO plays an important role in modulating the 2D nanosheet morphology of FA derived porous carbon, enhancing the e-conductivity and reducing the OFGs of porous carbons, which makes significant contribution to improving the structural stability and electrochemical performance of material. The obtained FG1% C/C composite simultaneously exhibits high specific surface area (2593 m2/g) and desirable e-conductivity (101 S m−1). More critically, it possesses highly stable surface chemical microenvironment with very-low surface oxygen content of 2.7 at.%, mainly existing as stable ether and quinone bonds. Thus, FG1% exerts ultra-high withstanding voltage up to 3.3 V in commercial TEABF4/PC electrolyte with the maximum energy density of 68.6 Wh kg−1, superior to most of the literatures, also it shows excellent stability throughout its lifespan, maintaining improved capacity retention rate (88.9%) at 2.5 A/g over 10,000 cycles. This work pares the way for the architecture design of high withstanding voltage porous carbon.

Analyzing the behavior of graphene oxide on high-strength rubberized concrete properties using different optimization techniques

Applying rubber aggregates (RA) obtained from used rubber tires in concrete is an innovative method to substitute natural aggregate (NA) to perform sustainable construction practices. RA in concrete is not only helpful to remove the burden of used rubber tire heaps from the earth but may also give a better alternative to the fast-depleting NA. Graphene oxide (GO) was mixed in the RC to modify the physical and mechanical properties of rubberized concrete (RC). An experimental study was performed on the sixteen different concrete samples of GO-mixed RC with the help of workability, density, air content, compressive strength, tensile strength, and flexural strength tests. The research findings indicated that GO had a beneficial impact by enhancing the density, compressive strength, tensile strength, and flexural strength by counteracting the detrimental effects caused by RA on concrete. Increments up to 0.72 %, 16.23 %, 8.82 %, and 6.48 %, respectively, were reported in the density, compressive strength, tensile strength, and flexural strength of RC after the inclusion of GO. However, the incorporation of GO tended to reduce workability (up to 13.04 %) and air content (by 1.5 %) in the RC. Different optimization techniques like response surface methodology (RSM), analysis of variance (ANOVA), and heatmap correlation were applied to the experimental results. Coefficients of determination were higher than 92 % for each GO-mixed RC property, indicating a higher goodness of fit for the experimental results.

Potential Value of Konjac Glucomannan Microcrystalline/Graphene Oxide Dispersion Composite Film in Degradable Plastics

Konjac glucomannan (KGM) is a promising bio-based material that can effectively mitigate the global petroleum-based plastic pollution exacerbated by the responses to COVID-19. This study first acidified KGM to obtain KGM microcrystals (MKGM) with a relatively low molecular mass. Next, different volumes of graphene oxide (GO) dispersions were mixed with MKGM to prepare composite films via physical cross-linking using glycerol as a plasticizer. The UV barrier capability, mechanical strength, thermal stability, and water resistance of these films were subsequently assessed. GO enhanced the tensile strength of the polysaccharide, while limiting its toughness. Thus, the tensile strength of the MKGM film improved from 7.80 MPa to 39.92 MPa following the addition of 12 mL of GO dispersion, and the elongation at break decreased from 46.31% to 19.2%. A morphological study revealed that the addition of different volumes of GO caused the composite films to exhibit various degrees of porosity and an enhanced water barrier capability. Introducing GO also improved the UV barrier capability and thermal stability of the composite film. Meanwhile, the composite films exhibited excellent degradation properties. Therefore, composite films prepared via the acidification of KGM and the incorporation of GO are suitable for extensive utilization in degradable plastics.

Preparation of polyvinyl alcohol/chitosan nanofibrous films incorporating graphene oxide and lanthanum chloride by electrospinning method for potential photothermal and chemical synergistic antibacterial applications in wound dressings

Electrospun fibres have been widely used as skin dressings due to their unique structur. However, due to the lack of intrinsic antimicrobial activity, it is easy for the wound to become infected. Bacterial infection, which leads to chronic inflammation, severely hinders the normal process of skin regeneration. In this study, a polyvinyl alcohol/chitosan (PVA/CS) composite films with chemical sterilization and near-infrared (NIR) photothermal antibacterial activity was fabricated by electrospinning. Graphene oxide (GO), a photosensitiser, was incorporated into the films, and lanthanum chloride (Lacl3) as a chemical antibacterial agent was also doped in the electrospun films. The structure, morphology, mechanical properties, wettability, and antimicrobial and photothermal antibacterial activity of the PVA/CS-based fibre films were investigated. The results showed that the addition of Lacl3 to the PVA/CS/GO nanofibres (PVA/CS/GO-La) improved the hydrophilicity, tensile strength and resistance to elastic deformation of the nanofibres. The PVA/CS/GO-La12.5 mM sample exhibited the best antibacterial performance, showing high inhibition against Staphylococcus aureus (82% antibacterial efficacy) and Escherichia coli (99.7% antibacterial efficacy). Furthermore, the antibacterial efficacy of the films surface was further enhanced after exposure to NIR light (808 nm, 0.01 W) for 20 min. In addition, the nanofibre films showed no cytotoxicity against human skin fibroblasts (HSFs), indicating its potential application in the field of broad-spectrum antibacterial materials.

Molecularly imprinted nanoparticles doped graphene oxide based electrochemical platform for highly sensitive and selective detection of L-tyrosine

A highly sensitive and selective electrochemical sensor was developed using a surface modified glassy carbon electrode (GCE) through molecularly imprinted polymerization on the surface of vinyltrimethoxysilane (VTMS) coated magnetic nanoparticle (Fe3O4) decorated silver nanoparticles incorporated graphene oxide, GO (VTMS-Fe3O4/AgGO) for L- Tyrosine (Tyr) detection. A molecular imprinting technique based on free radical polymerization was applied to synthesize molecularly imprinted Methacrylic acid (MAA) and Acrylamide (AA) grafted VTMS-Fe3O4/AgGO polymer (MAA/AA-g- VTMS-Fe3O4/AgGO) designated as MIP and non-imprinted polymer (NIP). The structure and morphology of the prepared polymers were FTIR, XRD, FE-SEM and VSM. MIP and NIP were chosen for modifying the GCE surface by drop casting process to construct the sensors and their electrochemical properties were characterized via EIS and CV. Compared with NIP/GCE sensor, MIP /GCE sensor exhibits excellent sensing response towards Tyr with a wide linear range of 0.25 × 10−13 M to 0.10 × 10−3 M and the limit of detection and limit of quantification as 0.15 × 10−13 M and 0.50 × 10−13 M, respectively with R2 value of 0.9934 by DPV technique. Moreover, MIP/GCE sensor exhibits long-time storage, excellent selectivity and good stability in multiple cycle usage. The practical applicability of MIP/GCE sensor was tested in human blood serum sample. The recovery percentage was obtained between 98.8% and 106.0% with a relative standard deviation (RSD) between 1.01% and 1.59%. Results of the investigations revealed the clinical applicability of the MIP/GCE sensor.

Enhancing Bioactivity of Nanofibrous Poly(Caprolactone)/45S5 Bioglass Composite Scaffolds by Incorporation of Ag, GO, and ZnO Nanoparticles.

The present study endeavors toward the investigation on the bioactivity of nanofibrous scaffolds manufactured by the electrospinning process. Nanofibrous composite scaffolds of PCL with 45S5 bioactive glass and metal oxide nanoparticles were developed and characterized. The effects of incorporating silver (Ag), graphene oxide (GO), and zinc oxide (ZnO) nanoparticles into PCL/bioglass nanofibrous scaffolds on its geometry and physiochemical, morphological, mechanical, and biological properties were studied. The incorporation of GO and ZnO alters the fiber diameter, suggesting the methodology for controlling the porosity of the scaffolds. The results of FTIR and XRD confirm the structure of bioglass, Ag, GO and ZnO nanoparticles. The in vitro degradation studies in SBF solution provide evidence for the enhancement in the rate of apatite formation by the inclusion of nanoparticles as compared with PCL/BG scaffolds. The assessment of mechanical properties suggests the tensile strength was increased from 1.61 to 5 MPa in PCL/BG/ZnO system when compared with pristine PCL. The cell viability is also observed to be improved from 72% to 91% and 104% for PCL/BG/GO and PCL/BG/ZnO, respectively. The hemolytic activity studies confirm that all scaffolds are nonhemolytic in nature and PCL/BG/ZnO exhibits the least hemolytic activity of 0.65% among the other composite scaffolds, suggesting the better blood compatibility. The present study evidently shows the fact that incorporation of GO and ZnO nanoparticles with PCL in addition to BG accelerates the bioactivity and improves the mechanical strength of the scaffold.

Incorporating graphene oxide into COF membranes enables ultrahigh proton conductivity and ultralow H2 crossover

Proton exchange membranes (PEMs) are the core components of electrochemical hydrogen energy production, storage and conversion devices. It is a great challenge to develop PEMs with a combination of high proton conductivity, minimal H2 crossover and mechanical robustness for achieving high efficiency and long-term stability in these devices. Here, a co-assembled PEM composed of ionic covalent organic framework (iCOF) nanosheets and functionalized graphene oxide (GO) nanosheets was presented. The iCOF (TpPa-SO3H) nanosheets and polydopamine-modified graphene oxide (DGO) nanosheets were co-assembled into TpPa-SO3H/DGO mixed nanosheets with ultrahigh aspect ratio, which were readily further processed into TpPa-SO3H/DGO co-assembled membranes. The abundant and uniformly distributed –SO3H groups on TpPa-SO3H nanosheets and the acid-base pairs formed between TpPa-SO3H and DGO nanosheets promoted proton conduction significantly. Additionally, the dense structured DGO nanosheets inhibited H2 crossover remarkably, and the multiple interactions between TpPa-SO3H and DGO nanosheets enhanced mechanical strength. The resultant TpPa-SO3H/DGO co-assembled membrane exhibited an ultrahigh proton conductivity of 916.4 mS cm−1 (80 °C, 100% RH), an unprecedently low H2 crossover of 9.7 barrer and a sufficient tensile stress of 87.8 MPa. The enhanced proton conduction and H2 barrier property led to enhanced performance in both electrochemical hydrogen compression and single hydrogen fuel cells.

Influence of graphene oxide on the long-term durability behaviour of high-strength rubberised concrete

Applying waste tire rubber as rubber aggregate (RA) in concrete is advantageous from the perspective of environmental sustainability. This study examines the action of graphene oxide (GO) on the durability properties of high-strength rubberised concrete (RC). The durability characteristics of concrete were assessed with the help of acid attack, water sorptivity, and rapid chloride penetration test (RCPT) on the hardened concrete specimens for the test periods of 7, 28, 56, and 90 days each. Acid attack tests (mass loss and compressive strength loss) were performed after immersing the concrete specimens in hydrochloric (HCl) and sulphuric (H2SO4) acids for the stipulated periods. The increased mass and compressive strength losses were observed with the incorporation of RA in concrete, which was finally mitigated by the action of GO in concrete. Water absorption was increased by RA alone but was reduced after the incorporation of GO in this RC. It was also observed that the chloride penetration was reduced after the incorporation of RA and GO in conventional concrete (CC). This study concludes that GO excellently strengthens the long-term durability properties of the RC.