Molybdenum Disulfide Nanoparticles Research Articles

A critical investigation on viscosity and tribological properties of molybdenum disulfide nano particles on diesel oil

Tribological properties are one of the important parameters of examining the performance of the diesel oil. Diesel oil is predominantly used everywhere and it is one of the important essentials in daily living. This study aims to examine the tribological and the thermo physical properties of molybdenum disulfide nano particles. In this work the nano particles were dispersed in 3 different concentrations such as 0.3, 0.5 and 0.7 weight percentages with the pure diesel oil. Molybdenum disulfide nano particles were immersed in diesel oil at different proportions. In this work a pin on disc tribometer were utilised to analyze the frictional properties. Wear properties of Molybdenum disulfide (MoS2) nano particles were analysed. The results reveal that the addition of molybdenum nano particles marginally reduced the wear properties. The other key properties such as nano fluids viscosity, viscosity index obtained the highest values at 0.7 weight percentages. Based on the results it was concluded that the frictional property had no impact on the anti friction and anti wear properties at different concentrations with diesel oil.

Molybdenum disulfide nanoparticles concurrently stimulated biomass and β-carotene accumulation in Dunaliella salina

Molybdenum disulfide nanoparticles (MoS2 NPs) hold tremendous properties in wide domain of applications. In this study, the impact of MoS2 NPs was investigated on algal physiological and metabolic properties and a two-stage strategy was acquired to enhance the commercial potential of Dunaliella salina. With 50 µg/L of MoS2 NPs exposure, cellular growth and biomass production were promoted by 1.47- and 1.33-fold than that in control, respectively. MoS2 NPs treated cells were subject to high light intensity for 7 days after 30 days of normal light cultivation, which showed that high light intensity gradually increased β-carotene content by 1.48-fold. Furthermore, analyses of primary metabolites showed that combinatorial approach significantly altered the biochemical composition of D. salina. Together, these findings demonstrated that MoS2 NPs at an optimum concentration combined with high light intensity could be a promising approach to concurrently enhance biomass and β-carotene production in microalgae.

Physiological and molecular responses in halotolerant Dunaliella salina exposed to molybdenum disulfide nanoparticles

Molybdenum disulfide nanoparticles (MoS2 NPs) has emerged as the promising nanomaterial with a wide array of applications in the biomedical, industrial and environmental field. However, the potential effect of MoS2 NPs on marine organisms has yet to be reported. In this study, the effect of MoS2 NPs on the physiological index, subcellular morphology, transcriptomic profiles of the marine microalgae Dunaliella salina was investigated for the first time. exhibited “doping-like” effects on marine microalgae; Growth stimulation was 193.55%, and chlorophyll content increased 1.61-fold upon the addition of 50 μg/L MoS2 NPs. Additionally, exposure to MoS2 NPs significantly increased the protein and carbohydrate content by 2.03- and 1.56-fold, respectively. The antioxidant system was activated as well to eliminate the adverse influence of reactive oxygen species (ROS). Transcriptomic analysis revealed that genes involved in porphyrin synthesis, glycolysis/gluconeogenesis, tricarboxylic acid cycle and DNA replication were upregulated upon MoS2 NPs exposure, which supports the mechanistic role of MoS2 NPs in improving cellular growth and photosynthesis. The “doping-like” effects on marine algae suggest that the low concentration of MoS2 NPs might change the rudimentary ecological composition in the ocean.

Thermophysical and wear properties of eco-friendly nano lubricants

Nano lubricants are widely used from heavy machinery to compact equipment to enhance their reliability. The research towards developing eco-friendly and biodegradable lubricants using natural oils has attracted the lubrication industries worldwide in recognizing the sustainable agrarian initiatives towards developing innovative green technologies. An attempt was made to investigate the use of vegetable oil-based nano lubricants prepared by dispersing molybdenum disulfide (MoS2) nanoparticles with the raw castor and olive oils, without adding surfactants or property modifiers. The prepared nano lubricants were tested for lubrication performance using a pin-on-disc tribometer, with EN31 as disc material and aluminum Al2024 as pin material. The wear study results are compared with the commercially available mineral oil, SAE20W40 multigrade engine oil. The castor and olive oil-based nano lubricants exhibited good thermal conductivity, higher flash point, and fire point, with better heat-carrying capacity comparatively with SAE20W40 engine oil. The study reported a 43% and 37% reduction in wear for a continuous sliding of 5 min, with castor and olive oil-based nano lubricants respectively compared with dry lubrication. Also, 56% and 51% improvement in thermal conductivity was observed for castor and olive oil reinforced with 0.7 wt% of MoS2 nanoparticles respectively, compared with SAE20W40 engine oil. The study revealed the possibility of using vegetable oil-based nanofluids as functional lubricants, which has better replacement potential with synthetic or petroleum-based mineral oils for tribological applications.

Assessment of jojoba as a pure and nano-fluid base oil in minimum quantity lubrication (MQL) hard-turning of Ti–6Al–4V: A step towards sustainable machining

The article presents a feasibility study on jojoba - a vegetable oil - as a candidate base oil mixed with and without molybdenum disulfide nano-particles (nMoS2) in hard-machining with minimum quantity lubrication (MQL). The jojoba oil is benchmarked against commercially available mineral oil (LRT 30) for machining of Ti–6Al–4V alloy. The machining performance in terms of cutting force, tool wear, and surface roughness is assessed under five cutting environments, namely, dry turning, MQL (jojoba oil and LRT 30), nanofluid MQL (jojoba oil + nMoS2 and LRT 30 + nMoS2) is evaluated applied with different concentrations of nanoparticles (0.1, 0.5, and 0.9% by weight). The results show that jojoba oil, in pure and nano-fluidic condition as well, presents itself as a strong and sustainable replacement for commercially available mineral oil for MQL turning. The improvement in performance with jojoba oil is attributed to long chain fatty acidic structure (monoesters), excellent thermal oxidative stability, high viscosity index, and lamellar structure of nMoS2. The MQL turning with jojoba oil + nMoS2(0.1%) is found to have a reduction in cutting force, surface roughness, and tool wear in the range 35–47%. The overall results show that jojoba oil, as well as jojoba oil with an optimum concentration of MoS2 nanoparticles, emerged as a sustainable machining alternative.

Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms.

Shewanella oneidensis MR-1 is a dissimilatory metal-reducing bacterium capable of reducing various metal and sulfur compounds and precipitating them in nanoparticulate form. Here, we report the synthesis of molybdenum disulfide nanomaterials at the site of S. oneidensis biofilms grown in the presence of molybdenum trioxide and sodium thiosulfate. Samples from the growth medium were imaged using scanning electron microscopy and characterized using transmission electron microscopy, energy-dispersive x-ray spectroscopy, absorbance spectroscopy, and x-ray diffraction. These methods revealed the presence of molybdenum disulfide nanoparticle aggregates 50-300 nm in diameter with both hexagonal and rhombohedral polytypes. As a biosynthesis method for molybdenum sulfide, the use of S. oneidensis offers the advantage of significantly reduced heat and chemical solvent input compared to conventional methods of synthesizing molybdenum disulfide nanoparticles.

Enhanced decomposition of H2O2 by molybdenum disulfide in a Fenton-like process for abatement of organic micropollutants

Accelerating the rate-limiting step of Fe3+/Fe2+ conversion is a major challenge for H2O2 decomposition in conventional Fenton process. In this study, the catalytic mechanism of H2O2 by molybdenum disulfide (MoS2) nanoparticles and Fe3+ ions was revealed and the abatement of organic micropollutants was investigated. The presence of both MoS2 and Fe3+ can efficiently decompose H2O2. Reaction system of H2O2/MoS2/Fe3+ is found to remove most of the tested pollutants by over 80% (except 65.9% for carbamazepine) within 60 min at pH of 3.0. Effective pH range of this reaction system can be extended to pH of 5.0. Adding MoS2 to Fe3+/H2O2 system promotes the Fe3+/Fe2+ cycle and improves the reaction rate between Fe3+ and H2O2. The formation of Mo6+ ions and Mo6+ peroxo-complexes is beneficial to H2O2 decomposition and pollutant degradation. Electron paramagnetic resonance (EPR) measurements and quenching experiments confirm the important role of hydroxyl radicals in H2O2/MoS2/Fe3+ system. Chloride ions (Cl−) promote degradation, while bicarbonate ions (HCO3−) inhibit degradation. As H2O2 concentration increases from nil to 1.0 mM, the value of total EE/O decreases from 0.083 to 0.003 kWh L−1, and the most energy efficient condition is determined. This study provides a new pathway for efficient decomposition of H2O2 by Fe3+ ions in an extended pH range, which is considered a facile and promising strategy for wastewater treatment.

Effect of Molybdenum Disulfide Nano-particles on Dry Sliding Behavior of Carbon Fiber Reinforced Epoxy

Effect of Molybdenum Disulfide Nano-particles on Dry Sliding Behavior of Carbon Fiber Reinforced Epoxy

Enhanced Heat Transfer in Moderately Ionized Liquid Due to Hybrid MoS2/SiO2 Nanofluids Exposed by Nonlinear Radiation: Stability Analysis

This study considers ethylene-glycol as a moderate ionized regular liquid whose rheological behavior can be analyzed through the relations of the Carreau stress–strain tensor. Hybrid nanoliquids are potent liquids that give better performance for heat transfer and the properties of thermo physical than regular heat transfer liquids (water, ethylene glycol, and oil) and nanoliquids by single nanomaterials. Here, a type of hybrid nanoliquid involving silicon oxide (SiO2) and Molybdenum disulfide (MoS2) nanoparticles with ethylene glycol as a base liquid are considered. In addition, the impact of nonlinear radiation along with Lorentz force is invoked. Similarity variables are utilized to acquire the numerical findings and their solutions for transmuting ordinary differential equations (ODEs). Using bvp4c from MATLAB, we can obtain these quantitative and numerical results of the converted nonlinear equations. The impacts of the pertinent constraints on the temperature distribution, velocity, Nusselt number, and skin friction are estimated. The outcomes indicate that the double-edged methods for the results originate from the precise values of the permeable parameters. Further, the critical values (Sc = 1.9699, 2.0700 and 2.2370) are enhanced due to the influence of the local Weissenberg number. This implies that the increasing value of the local Weissenberg number accelerate the boundary layer separation. Furthermore, a stability investigation is performed and confirms that the first solution is a physically reliable solution.

Fabrication of biopolymer polyhydroxyalkanoate/chitosan and 2D molybdenum disulfide-doped scaffolds for antibacterial and biomedical applications.

Antibiotic resistance in pathogenic bacteria is a major health challenge, as Infectious Diseases Society of America (IDSA) has recognized that the past simply drugs susceptible pathogens are now the most dangerous pathogens due to their nonstop growing resistance towards conventional antibiotics. Therefore, due to the emergence of multi-drug resistance, the bacterial infections have become a serious global problem. Acute infections feasibly develop into chronic infections because of many factors; one of them is the failure of effectiveness of antibiotics against superbugs. Modern research of two-dimensional nanoparticles and biopolymers are of great interest to attain the intricate bactericidal activity. In this study, we fabricated an antibacterial nanocomposite consisting of representative two-dimensional molybdenum disulfide (2D MoS2) nanoparticles. Polyhydroxyalkanoate (PHA) and chitosan (Ch) are used to encapsulate MoS2 nanoparticles into their matrix. This study reports the in vitro antibacterial activity and host cytotoxicity of novel PHA-Ch/MoS2 nanocomposites. PHA-Ch/MoS2 nanocomposites were subjected to time-dependent antibacterial assays at various doses to examine their antibacterial activity against multi-drug-resistant Escherichia coli K1 (Malaysian Type Culture Collection 710859) and methicillin-resistant Staphylococcus aureus (MRSA) (Malaysian Type Culture Collection 381123). Furthermore, the cytotoxicity of nanocomposites was examined against spontaneously immortalized human keratinocyte (HaCaT) cell lines. The results indicated significant antibacterial activity (p value < 0.05) against E. coli K1 and MRSA. In addition, PHA-Ch/MoS2 showed significant host cytocompatibility (p < 0.05) against HaCaT cells. The fabricated PHA-Ch/MoS2 nanocomposites have demonstrated effective antibacterial activity against both Gram-positive and -negative bacteria and exhibited better biocompatibility. Finally, PHA-Ch/MoS2 nanocomposites are shown to be suitable for antibacterial applications and also hold potential for further biomedical studies. Graphical Abstract.

Shape effects of molybdenum disulfide (nm) micro-rotating particles in crosswise transport of hydrogen oxide: (MoS2–H2O) nano polymer gel

Nano polymers have emerged as a new development offering promising durability, anti-corrosion and thermal efficiency. Nanoparticles shape, size and volume fraction plays critical part in improved performance of heat exchanger systems involving modern manufacturing processes of nano-rheological materials. Molybdenum Disulfide nanostructures finds significant applications in desulfurization processes, in thermoelectric appliances and many more. Motivated by elaborating in further detail, the present article presents a mathematical and computational study on steady, two-dimensional, non-aligned thermo-fluid transport of Molybdenum Disulfide doped-Hydrogen oxide (H2O) based micropolar fluid. To simulate real nano polymer dynamics, the Tiwari-Das model for nano particle concentration and Maxwell-Garnet model for nanofluid thermal conductivity is exploited. The conservation equations for mass, momentum (normal and tangential) and energy are normalized by employing suitable transformations. Numerical solutions are attained via Keller Box method in MATLAB symbolic software. The impact of key emerging dimensionless parameter i.e. nanoparticles volume fraction and various shape effects of molybdenum disulfide nanoparticles on non-dimensional normal and tangential velocity components, micro rotation profile, temperature, shear stress at the wall and local heat flux is explored graphically. Local heat flux and micro-rotation profile is boosted while tangential skin friction coefficient depletes with the insertion of blade shaped nanoparticles. Moreover greatest thermal conductivity is achieved with the insertion of blade shape nanoparticles.

Preconcentration and Determination of Trace Hg(II) Using a Cellulose Nanofiber Mat Functionalized with MoS2 Nanosheets

Molybdenum disulfide (MoS2) nanoparticles were hydrothermally synthesized onto the surface of a cellulose nanofiber mat and demonstrated for the selective extraction and preconcentration of trace Hg(II) from aqueous media. Immobilization of MoS2 onto solid support restricts sorbent loss during a column operation. The surface morphology and chemical bonding of the prepared material were characterized by scanning electron microscopy, tunneling electron microscopy, and X-ray photoelectron microscopy. The selective sorption of Hg(II) is mainly attributed to the soft–soft interaction of Hg(II) with the S atoms of the MoS2. The experimental data shows good Hg(II) sorption capacity and was found to be 160.4 mg g–1. The limit of detection and limit of quantification of the proposed method were found to be 0.09 and 0.30 μg L–1, respectively. The accuracy of the method against the systematic and constant errors was confirmed by the analysis of the Standard Reference Material (>95% recovery with <5% RSD). Student’s ...

THE EFFECT OF MOLYBDENUM DISULFIDE NANOPARTICLES AND SODIUM DODECYL SULFATE ADDITION TOWARDS WEAR PROTECTION PROPERTIES FROM THE SAE 10W-30 STANDARD LUBRICANTS

The use of modified lubricants on the engine could lead to the efficiency of energy use. This research aimed toinvestigate the effect of molybdenum disulfide (MoS2) nanoparticles and Sodium Dodecyl Sulfate (SDS) addition tothe SAE-10W-30 standard lubricant that is formulated from three basic oils (HVI-60, HVI-95, and Yubase-8). Thepreparation of SAE-10W-30 standard lubricants was performed by mixing the three basic lubricants in a beakerglass, followed by a stirring process with a speed of 330 rpm at 50oC for 60 minutes. MoS2 nanoparticles and SDSwere added to the mixture with varying concentrations of optimum concentrations of 0.1% wt and 0.2% wtrespectively.

DARCIAN SLIP FLOW OF ROTATING MAGNETOREACTIVE PEG CONVEYING MoS2 CASSON NANOFLUID WITH RAMPED TEMPERATURE AND CONCENTRATION

An analysis is presented to assess the impact of slip condition and rotation on an unsteady hydromanetic Darcy flow of a viscous incompressible electrically conducting non-Newtonian Casson nanofluid past an infinite oscillating vertical plate with ramped heating and concentration embedded in a homogeneous porous medium in the presence of thermal radiation and homogeneous chemical reaction of first order. The nanofluid is composed of molybdenum disulfide (MoS2) nanoparticles suspended in base fluid polyethylene glycol (PEG). A Casson fluid model presents the non-Newtonian fluid behavior. Rosseland approximation for an optically thick fluid is used to describe the radiative heat flux in the energy equation. The classical Dracy model simulates drag effects in the porous medium. The resulting simultaneous ordinary equations governing the flow are solved analytically in closed form by employing the Laplace transform technique. Graphical presentations are portrayed to examine the physical consequences of intricate physical parameters on the pertinent flow characteristics. The obtained results reveal that the velocity components are strongly diminished by intensifying magnetic parameter or slip parameter. The wall shear stresses are increasing functions of rotation parameter. This study finds applications in magnetic material processing and electrically conducting polymer dynamics.

Tribological behavior of mineral and synthetic ester base oil containing MoS2 nanoparticles

0.2, 1.0, and 2.0 wt.% concentration of molybdenum disulfide (MoS2) nanoparticles were dispersed in mineral and synthetic ester base oil. Their tribological behavior investigated using a tribometer with pin-on-disk and four-ball configuration under different conditions of contact pressures, sliding speeds and oil bath temperatures, respectively. The results demonstrate that nano-MoS2 in mineral oil can reduce wear and friction coefficient characteristics at all concentrations tested, especially at 2.0 wt.%. XPS analysis of the worn surfaces indicated that decomposed MoS2 was adsorbed on worn surface, and S and Mo elements of the compound reacted with the metal and existed in the form of sulfide or molybdenum compounds, both of which contributed to the formation of a mix lubricating film. A wear mechanism of MoS2 as antiwear additive is proposed.

MoS2 nanoparticles induce behavioral alteration and oxidative stress mediated cellular toxicity in the social insect Oecophylla smaragdina (Asian weaver ant)

The study evaluates molybdenum disulfide (MoS2) nanoparticles (NPs) induced oxidative stress during cellular toxicity in an invertebrate in vivo system, the weaver ant. The lethal concentration was checked and LC50 was obtained as 50 µg/mL. Feeding assay and the photoluminescence activity confirmed the ingestion of MoS2 NPs by the organism. Behavioral assays showed altered grooming behavior in the MoS2 NP fed ants. A drastic decrease in the hemocyte count in the MoS2 NP fed ants revealed the anti-proliferative role of MoS2. This was further confirmed by 5-bromo-2′-deoxyuridine (BrdU) labeling assay. MoS2 NPs induced apoptotic activity was also observed in the hemocytes by acridine orange/ethidium bromide (AO/EB) staining. The level of oxidative stress during cellular toxicity was observed. An increased reactive oxygen species (ROS) level was observed in the MoS2 NP fed ants when compared to the control group. The increased activity of superoxide dismutase (SOD) and the lipid peroxidation (LPO) product were observed. While, the activities of catalase (CAT) and glutathione-s-transferase (GST) and the glutathione content (GSH) were decreased by MoS2 NPs. The transcript levels of SODs, CAT and GST were up regulated in the treated group. Our results suggest that MoS2 NPs induced oxidative stress mediates the cellular toxicity in the foragers of the weaver ant.

Scrutinization of different shaped nanoparticle of molybdenum disulfide suspended nanofluid flow over a radial porous fin

Purpose The purpose of this paper is to study the thermal behaviour of radial porous fin wetted with nanofluid containing different shaped nanoparticles in the presence of natural convection and radiation. Here, the nanofluid suspended with molybdenum disulfide nanoparticle with base fluid as water is considered. The influence of non-spherical nanoparticles such as platelet, cylinder, brick and blade shapes is also investigated. Design/methodology/approach The modeled equations are non-dimensionalized and solved numerically via Runge–Kutta–Fehlberg method combined with shooting scheme. Findings The flow natures of the pertinent parameter are represented graphically and discussed their physical significance. From the validation of obtained outcome, it is found that the use nanofluid has significant influence on heat transfer rate. Among platelet, cylinder, brick and blade shapes, brick-shaped nanoparticle shows better heat transfer rate. Originality/value The present paper deals with an analysis of the flow of molybdenum disulfide nanoparticles suspended in water over a porous fin of a radial profile. The effect of differently shaped nanoparticles on the heat transfer enhancement through the radial porous fin is investigated for the first time. The natural convection and radiation effects are also considered. The modeled equations are non-dimensionalized and solved numerically via Runge–Kutta–Fehlberg method combined with shooting scheme. The effect of pertinent parameters on temperature field is examined. From the validation of obtained outcome it is found that the use nanofluid has significant influence on heat transfer rate. Among platelet, cylinder, brick and blade shapes, brick-shaped nanoparticle shows better heat transfer rate.

Simulation and Sensitivity Analysis of Molybdenum Disulfide Nanoparticle Production Using Aspen Plus

The sensitivity analysis of molybdenum disulfide nanoparticles synthesis process is studied using Aspen Plus with the aim of investigating the effect of reactants’ amounts on the production of molybdenum disulfide nanoparticles. The adopted approach consists in simulating the synthesis process based on experimental data, obtained at laboratory scale followed by sensitivity analysis with respect to the following precursors: ammonium heptamolybdate, elemental sulfur, and hydrazine used as a reducing agent. The sensitivity analysis revealed that the precursors have more significant impact on the obtained amount of molybdenum disulfide compared to hydrazine. The obtained result showed that the approach adopted in the study might be of interest for further investigation of the process design and scaling-up.

Q-switched erbium-doped fiber laser with molybdenum disulfide (MoS2) nanoparticles on D-shaped fiber as saturable absorber

In this study, short [Formula: see text]-switching laser pulses are generated by drop-casting two-dimensional Molybdenum Disulfide (MoS[Formula: see text] nanoparticles as saturable absorbers (SA) on a side polished optical fiber in a [Formula: see text]-band laser cavity. The proposed laser is capable of generating highly stable [Formula: see text]-switched laser pulses at the wavelength of 1559.42[Formula: see text]nm with a maximum repetition rate of 73.96[Formula: see text]kHz, and a minimum pulse width of 1.93[Formula: see text][Formula: see text]s. The relatively high signal-to-noise ratio of 58.7[Formula: see text]dB indicates a highly stable output. The proposed SA can be applied in a variety of fields due to its ease of manufacturing and cost-effectiveness as well as its robust and compact design.

Experimental investigation of MoS2/diesel oil nanofluid thermophysical and rheological properties

Thermophysical and tribological properties of traditional lubricant has important role in proper performance of industrial equipment and transportation vehicles. Diesel oil is wide used lubricant with very limited studies on its properties and this study aimed to evaluate the tribological and thermo-physical properties of diesel oil containing molybdenum disulfide (MoS2) nanoparticles. The nanoparticles were dispersed at 0.1, 0.4 and 0.7 wt% in each pure diesel oil. To assess the friction and wear properties of MoS2 nano-lubricant, pin-on-disc friction and wear tester were used. In this study, it was proved that mixing MoS2 nanoparticles in diesel oil increases nanofluids viscosity, viscosity index; the highest viscosity and viscosity index were found at 0.7 wt%. The findings also showed that the additives involved no significant anti-friction and anti-wear properties effect at different concentrations compared to the pure diesel oil. Furthermore, the MoS2 nanoparticles in diesel oil could not significantly alter the friction factor values in comparison with pure oil. The experimental results indicated that the addition of MoS2 nanoparticles to diesel oil had no significant effects on anti-wear properties and also concentration impact on the tribological performance of lubricant is negligible.