Graphene Oxide Hybrid Nanoparticles Research Articles

Augmenting the double pipe heat exchanger efficiency using varied molar Ag ornamented graphene oxide (GO) nanoparticles aqueous hybrid nanofluids

The optimization of heat transfer in heat exchanging equipment is paramount for the efficient management of energy resources in both industrial and residential settings. In pursuit of this goal, this empirical study embarked on enhancing the heat transfer performance of a double pipe heat exchanger (DPHX) by introducing silver (Ag)-graphene oxide (GO) hybrid nanofluids into the annulus of the heat exchanger. To achieve this, three distinct molar concentrations of Ag ornamented GO hybrid nanoparticles were synthesized by blending GO nanoparticles with silver nitrate at molarities of 0.03 M, 0.06 M, and 0.09 M. These Ag-GO hybrid nanoparticles were then dispersed in the base fluid, resulting in the formation of three distinct hybrid nanofluids, each with a consistent weight percentage of 0.05 wt%. Thorough characterization and evaluation of thermophysical properties were performed on the resulting hybrid nanomaterials and nanofluids, respectively. Remarkably, the most significant enhancement in heat transfer coefficient, Nusselt number, and thermal performance index (62.9%, 33.55%, and 1.29, respectively) was observed with the 0.09 M Ag-GO hybrid nanofluid, operating at a Reynolds number of 1,451 and a flow rate of 47 g/s. These findings highlight the substantial improvement in thermophysical properties of the base fluid and the intensification of heat transfer in the DPHX with increasing Ag molarity over GO. In summary, this study emphasizes the vital importance of optimizing the molarity of the material, which also plays a significant role in nanoparticle synthesis to achieve the optimal amplification of heat transfer.

Fabrication of MIL-88A sandwiched in graphene oxide nanocomposites using a green approach to induce active/barrier protective functioning in epoxy coatings

The MIL-88A as a Fe+3/fumarate-based metal-organic framework (MOF) was used for the modification of graphene oxide (GO). This MOF was grown successfully on GO sheets to achieve active corrosion inhibition and to improve barrier effect against corrosive agents. The electronic density functional theory with dispersion correction functional (DFT-D) computations revealed the interactions between the GO sheets and the complexes. The electrochemical impedance spectroscopy (EIS) and polarization analysis revealed an increase in the total resistance (79%) and a reduction in corrosion current density (83%) after 5 h immersion in the saline solution containing optimally synthesized MIL-88A/GO hybrid nanoparticles. This anti-corrosion pigment released 3.6 ppm Fe+3 and 225 ppm total carbon according to inductively coupled plasma-optical emission spectrometry and total organic carbon experiments. The scratched epoxy coatings with 0.15% of this nanocomposite showed active inhibition in EIS and salt spray study. Higher wet/dry adhesion strength values were detected in the coating incorporating synthesized particles. Also, the cathodic delamination results indicated a 50% and 42% decrement in the disbonded area compare to neat epoxy and epoxy/GO coatings, respectively. Finally, the EIS measurement confirmed modified GO sheets' excellent barrier effect. The coating damage percentage was calculated by the broad frequency range analysis method. The results expressed that the epoxy and epoxy-GO had 100% and 79% damage index after 105 days, while the damage index for the MIL-88A/GO epoxy coating was 4%.

Modification of polyvinylidene fluoride membrane by silver nanoparticles-graphene oxide hybrid nanosheet for effective membrane biofouling mitigation

Membrane biofouling poses severe impacts on the membrane lifespan and performance. In this study, a silver nanoparticles-graphene oxide hybrid nanosheet (AgNPs-GO) was synthesized as a bactericidal agent for effective membrane biofouling mitigation. The surface polymerization between polyvinyl alcohol (PVA) and AgNPs-GO nanosheet improved the stability of inorganic biocidal materials on the membrane surface and had a significant effect on the permeability and rejection performance of membranes. The PVA/AgNPs-GO modified hydrophilic polyvinylidene fluoride (H-PVDF) membrane exhibited an excellent anti-microbial activity in both static contact and filtration modes; nearly 100% inactivation of Pseudomonas aeruginosa in solution and 91% reduction in the membrane surface adhesion were found. The composite membrane with good stability and anti-microbial ability may offer an alternative to alleviate membrane biofouling problem.

Fabrication of aluminum TIG welding filler rods reinforced by ZrO2/reduced graphene oxide hybrid nanoparticles via accumulative roll bonding

In the present study, accumulative roll bonding (ARB) was utilized to incorporate ZrO2/reduced graphene oxide (rGO) hybrid nanoparticles into the 1100 aluminum matrix to fabricate composite filler rods of tungsten inert gas (TIG) welding. After welding, microstructures and distribution of hybrid nanoparticles were analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that by increasing the number of ARB cycles, the hybrid nanoparticles were uniformly distributed in the filler rods. The tensile strength and microhardness of the nanoparticle-reinforced weld metals have an obvious improvement compared to that of unreinforced weld metal, but the elongation show a decrease. This improvement in the mechanical properties was attributed to the grain refinement and homogeneous dispersion of hybrid nanoparticles as well as the good interfacial bonding between the hybrid nanoparticles and aluminum matrix resulted from the ARB technique.

Copper supported β-cyclodextrin functionalized PEGylated mesoporous silica nanoparticle -graphene oxide hybrid: An efficient and recyclable nano-catalyst for straightforward synthesis of 2-arylbenzimidazoles and 1,2,3-triazoles

β-Cyclodextrin functionalized PEGylated mesoporous silica nanoparticles-graphene oxide hybrid has been introduced as a heterogeneous support for immobilization of copper catalyst (denoted as Cu@βCD-PEG-mesoGO). Mesoporous silica nanoparticles-graphene oxide hybrid (mesoGO) was synthesized and functionalized by PEG600 ended β-cyclodextrin. Then, Cu was immobilized onto the later modified nanoparticles. Cu@βCD-PEG-mesoGO was evaluated for the synthesis of benzimidazoles and 1,2,3-triazoles. The synthesis of 2-aryl benzimidazole derivatives from o-phenylenediamines and benzaldehydes via aerobic C-N bond oxidation reaction was successfully performed using Cu@βCD-PEG-mesoGO as a “green” catalyst. The catalyst was also applied for the synthesis of 1,2,3-triazole derivatives via three component click reaction of alkynes, benzylbromides and sodium azide. The catalyst recovery test was performed, and showed that this catalyst is highly reusable without a significant decrease in its activity. This catalyst has outstanding properties such as high efficiency and turnover frequency (TOF), simple product work-up, utilization of H2O as a green solvent, mild reaction conditions, and easy catalyst recovery.

Facile Synthesis of Pd Nanoparticles-Graphene Oxide Hybrid and Its Application to the Electrochemical Determination of Rutin

Facile Synthesis of Pd Nanoparticles-Graphene Oxide Hybrid and Its Application to the Electrochemical Determination of Rutin