Disulphide Nanoparticles Research Articles

Enhanced electrochemical stability of poly(pyridylthiophene) with zirconium dioxide/zirconium disulphide nanocomposites for high-performance supercapacitors

Zirconium dioxide (ZrO2) and zirconium disulphide (ZrS2) nanoparticles were added to poly(pyridylthiophene) (PPT) to improve its electrochemical stability. Characterization and comparison with pristine PPT were conducted to understand the surface influence, crystalline structure, and electrochemical performance of the PPT/ZrO2/ZrS2 material. Without reducing its available specific capacitance, surface modification can increase PPT’s structural stability. Through the use of AC impedance and cyclic voltammetry (CV) methods in a 3 M KOH electrolyte, the electrochemical characteristics of the produced PPT/ZrO2/ZrS2 electrode were assessed. PPT, PPT/ZrO2, PPT/ZrS2, and PPT/ZrO2/ZrS2 each had specific capacitances of 265, 655, 747, and 1326F/g at 5 A/g. The Zr4+ ions’ synergistic impact in the PPT/ZrO2/ZrS2 electrode material is responsible for this improvement. The energy and power density of the PPT/ZrO2/ZrS2 electrode in KOH are 166 Wh kg−1 and 664 W kg−1, respectively. After 10,000 cycles, the capacitance only loses 4 % of its initial value. The resulting PPT/ZrO2/ZrS2 nanocomposite included multilayer structures that were extremely stable and porous. The PPT/ZrO2/ZrS2 nanocomposites perform well electrochemically and structurally, making them suitable materials for use in supercapacitors.

Channel flow dynamics of fractional viscoelastic nanofluids in molybdenum disulphide grease: A case study

Nanoscopic fluids especially viscoelastic Nanofluids are very useful in engineering and industrial problems. This research is to determine the open channel flow of a viscoelastic nanofluid (namely Oldroyd-B (OBNF)). Oldroyd-B fluid (OBF) was used as the base fluid and molybdenum disulphide nanopatrials were added in the fluid to form desired OBNF. To convert the mathematical model to a fractional model from a classical order partial differential equation PDE, fractional type derivative named Caputo-Fabrizio (CF) was used. The main objective of this study is to find the exact mathematical solution for the temperature, concentration and velocity distributions by using integral transformation technique. Final results are discussed graphically for the influence of different parameters on calculated temperature, concentration and velocity. Skin friction of the said fluid and engineering related dimensionless numbers including Reynolds number (Re), Prandtl number (Pr), Grashof number (Gr) and Schmidt number (Sc) are also discussed. At the end a comparison is illustrated in graphical form between current studied fluid (i.e. OBNF), another non-Newtonian fluid (i.e. Maxwell Nanofluid (MWNF)) and Newtonian fluid. As we know speed of Newtonian fluid is greater than non-Newtonian fluid, the same statement is validated by our solution. It is also noted that adding molybdenum disulphide nanoparticles to grease, heat transmission increased to 19.11% and mass transmission decreased to 2.51%.

Molybdenum disulphide nanoparticles accelerate the transformation of levofloxacin in planting soil upon exposure

The use of nanocatalytic particles for the removal of refractory organics from wastewater is a rapidly growing area of environmental purification. However, little has been done to investigate the effects of nanoparticles on soil-plant systems with antibiotic contamination. This work assessed the effect of molybdenum disulfide (MoS2) on the soil-Phragmites communis system containing levofloxacin (LVX). The results showed that the addition of MoS2 had restoration potential for stressed plant. The MoS2 with catalytic activity promoted the transformation of LVX in rhizosphere soils. The transformation pathways of LVX in the different exposure groups were proposed. The continuous output of radicals in the high MoS2 dosage group facilitated the transformation of LVX to small molecule compounds, which were eventually mineralized. Moreover, the electron-density-difference analysis revealed the easier flow of electrons from the MoS2 surface towards the LVX molecules. This finding provides theoretical support for the application of nanocatalytic particles in ecological environments.

Influence of Molybdenum Disulphide (MoS2) Nanoparticles Loading in Treated Used Palm Oil Bio-lubricant on Surface Roughness during Turning of AISI420

The environmental impact and non-biodegradability of petroleum-based lubricants has caused some researchers to shift the formulation of lubricant formulation using plant-based oil, However, food security has caused concerns in development of new bio-lubricants. In this study, treated used cooking palm oil added with Zinc Dialkyldithiophosphate and Molybdenum Disulphide nanoparticles were used as lubricant to assist the cutting of hardened martensitic stainless steel AISI420 using coated carbide tool. Surface roughness of the cut workpiece was investigated using a surface roughness tester. From the study, treated used cooking oil added with ZDDP and 0.8wt% MoS2 nanoparticles displayed the lowest average surface roughness of workpiece with Ra = 0.532µm and total roughness Rz = 4.006µm. This concluded that the new formulated bio-lubricant can successfully replace the readily available commercial cutting fluid as it produces a low surface roughness during cutting process.

Self-assembled cobalt disulfide-graphene oxide composite for efficient and environmentally friendly removal of antibiotic ornidazole through PMS activation

In this study, a highly active peroxymonosulfate (PMS) activator was prepared by the self-assembly of cobalt disulphide (CoS2) nanoparticles on the surface of graphene oxide nanosheets using a simple electrostatic self-assembly method. The catalysts were characterized, and their ability to activate PMS to eliminate ornidazole (ORZ) was assessed. Degradation experiments showed that the CoS2−GO/PMS system exhibited excellent ORZ degradation performance, removing 99.7 % of ORZ in 10 min. In four consecutive cycles, the reduction rate of ORZ removal by the composite catalyst decreased by only 1.8 %. Both radical quenching experiments and electron paramagnetic resonance (EPR) tests revealed that sulfate radical (SO4•-) and superoxide radical (O2•-) contributed to the major reactive oxygen species (ROS). X-ray photoelectron spectroscopy (XPS) results showed that the sulfur (S) species in CoS2 played an important role in the Co(III)/Co(II) cycle, driving the catalyst to exhibit excellent PMS activation. Liquid chromatography-mass spectrometry (LC-MS) was used to determine the possible decomposition processes and identify the intermediates of the ORZ medium. Remarkably, the biotoxicity assessment of degraded intermediates analyzed by ECOSAR software indicated the environmentally friendly features of the degradation process.

Chemoprotective Effect of Phyllanthus emblica Molybdenum Disulphide (MoS2) Nanoparticles on Bleomycin-Induced Cytotoxicity in Human Lymphocytes

Following the world's largest nuclear accident at Fukushima in 2011, a lot of research has been conducted to try to minimize the potential health effects of radiation exposure. One way to do this is to use natural antioxidants to protect against oxidative DNA damage. We studied the effects of an Phyllanthus emblica fruit crude extract MoS2 NPs against bleomycin-induced cytotoxicity in human lymphocytes to see if it increases the overall chemoprotective mechanism. We analyzed the frequency of micronuclei (MN) and DNA damage after treatment with different concentrations of bleomycin. We observed a significant increase in cell viability in lymphocytes treated with Phyllanthus emblica fruit crude extract MoS2 NPs and then exposed to bleomycin induced cytotoxic cells. When lymphocytes were pretreated with Phyllanthus emblica fruit crude extract MoS2 NPs (80 and 100 μg/mL), the frequency of micronuclei was decreased at all doses of bleomycin and DNA damage was decreased at 20 μg/mL of bleomycin induced cytotoxicity human lymphocytes. These results suggest that Phyllanthus emblica fruit crude extract MoS2 NPs may have chemoprotective effects by performing CBMN assay.

Elasto-hydrodynamic lubrication analysis of a porous misaligned crankshaft bearing operating with nanolubricants

In this paper, the combined effects of the characteristic size and concentration of inorganic fullerene-like tungsten disulphide nanoparticles (IF-WS2 NPs) or molybdenum disulphide nanoparticles (IF-MoS2 NPs) on the nonlinear dynamic behaviour of a gasoline engine crankshaft bearing subject to an arbitrary force torsor (effective applied force and moment vector) are theoretically and numerically investigated using the V. K. Stokes micro-continuum theory. These NPs are the most common additives for lubrication purposes due to their excellent tribological characteristics along with their effect on reducing friction and wear. It is assumed that the journal (crankshaft) currently made of a forged steel is rigid and the main bearing consists of a thin poroelastic liner made of low elastic modulus materials like Babbitt metals fixed in a stiff housing as defined by ASTM B23-00. The Krieger-Dougherty law is included in the proposed EHD model to account for the viscosity variation with respect to the volume fraction of nanoparticles dispersed in the base lubricant. On the other hand, the characteristic size of nanomaterials is introduced by a new material entity, denoted l, which is responsible for a couple-stress property. The Reynolds equation is derived in transient conditions and modified to account for the size of nanoparticles and the bearing-liner permeability property. For an arbitrary force torsor, the hydrodynamic pressure distribution, the squeeze film velocities, and the misalignment angular velocities are determined simultaneously by solving the discretized Reynolds equation and the equilibrium equations with the damped Newton-Raphson iterative method at each crank angle step. The crankshaft center trajectories in three sections of the main journal axis as well as the misalignment angles are deduced from the squeeze film velocities and the misalignment angular velocities by means of a Runge-Kutta scheme. According to the obtained results, the combined effects of the size and concentration of fullerene-like nanoparticles on the dynamic behavior of a compliant dynamically loaded crankshaft bearing operating with dynamic misalignment are significant and cannot be overlooked.

Fractional simulations for thermal flow of hybrid nanofluid with aluminum oxide and titanium oxide nanoparticles with water and blood base fluids

Abstract The fractional model has been developed for the thermal flow of hybrid nanofluid due to the inclined surface. The thermal investigation of the hybrid nanomaterial is predicted by utilizing the molybdenum disulphide nanoparticles and graphene oxide nanomaterials. The flow computations for mixed convection flow of nanoparticles and base fluids are performed due to vertical oscillating plate. The simulations for the formulated model have been done ρ-Laplace transform technique for Caputo fractional simulations. Definitions of Mittage–Leffler function and ρ-Laplace transform are also presented for the governing model. The application of updated definitions of ρ-Laplace transform for the Caputo fractional model is quite interesting unlike traditional Laplace transforms. The comparative investigation for both types of nanoparticles is performed for heat and mass transfer rates. It is observed that the heat enhancement rate due to water-based nanoparticles is relatively impressive compared to the kerosene oil-based nanomaterials.

Polyaniline (PANI)-conjugated tungsten disulphide (WS2) nanoparticles as potential therapeutics against brain-eating amoebae.

Brain-eating amoebae, including Acanthamoeba castellanii and Naegleria fowleri, are the causative agents of devastating central nervous system infections with extreme mortality rates. There is an indisputable urgency for the development of effective chemotherapeutic agents for the control of these diseases that are increasing in incidence. Here, we evaluated the anti-amoebic potential of polyaniline:tungsten disulphide (PANI:WS2) nanocomposite against the infective trophozoite and cyst stages of N. fowleri and A. castellanii. Throughout these evaluations, significant viability inhibition was noted when 100µg/mL of PANI:WS2 was employed at its 1:5 formulation. These effects were studied to be due to increased levels of reactive oxygen species (ROS) as visualised through fluorescence microscopy. Furthermore, field emission scanning electron microscopy (FE-SEM) analysis pictured disruption to amoeba morphology. The host-cell cytotoxicity of the nanocomposite (PANI:WS2) was studied to be negligible, making it an attractive avenue in the pursuit for effective treatments for brain-eating amoeba infections. KEY POINTS: • Synthesis of polyaniline:tungsten disulphide (PANI:WS2) nanocomposite. • Anti-amoebic potential of PANI:WS2 nanocomposite. • PANI:WS2 nanocomposites are promising anti-amoebic agents in vitro.

Cytotoxic and pro-inflammatory effects of molybdenum and tungsten disulphide on human bronchial cells

Abstract This study aimed to investigate the cytotoxicity and pro-inflammatory responses induced by tungsten disulphide (WS2) and molybdenum disulphide (MoS2) nanoparticles (NPs) in human bronchial cells (BEAS-2B). For cytotoxicity assessment, the cells were exposed to different concentrations (2.5–200 µg/mL) of WS2-NPs or MoS2-NPs for 24 and 48 h and then the MTT assay was performed. Afterwards, long-term toxicity was assessed by the colony forming efficiency assay (CFEA) during a 10 days’ exposure of the cells. For pro-inflammatory responses, the expression of interleukin-6 (IL-6) and interleukin-1β (IL-1β) mRNA was estimated by the real-time PCR method. Both nanomaterials showed similar cytotoxic effects on BEAS-2B cells assessed by the MTT assay, i.e. reduction in cell viability to approx. 60–70% at concentrations of 2.5 and 5 μg/mL after 24 and 48 h. The percentage viability remained relatively constant at this level across all concentrations above 5 μg/mL. In long-term exposure, both nanomaterials inhibited colony formation in a wide range of concentrations up to 100 µg/mL. MoS2-NPs were slightly more cytotoxic than WS2-NPs. Additionally, MoS2-NPs caused an increase in mRNA levels of cytokines, IL-1β, and IL-6 at concentration of 50 µg/mL, while WS2-NPs did not cause any changes in the level of mRNA for both cytokines. We also visualised the changes in the cells as a result of WS2-NPs or MoS2-NPs exposure (2.5 and 25 µg/mL) via holotomographic microscopy. This work demonstrates the hazardous potential of both nanomaterials and indicate that WS2 and MoS2 nanoparticles should be included in the occupational risk assessment.

MoS2-based nanofluids as heat transfer fluid in parabolic trough collector technology

Concentrating solar power is becoming one of options for producing energy to replace conventional polluting energy sources. However, improving the efficiency and reducing the cost of technologies based on this type of energy to make it more competitive is still a work in progress. This study proposes replacing the thermal oil used as the heat transfer fluid in the absorber tubes of parabolic trough solar collectors (PTCs) with nanofluids based on spherical molybdenum disulphide nanoparticles with the aim of improving the thermal efficiency of concentrating solar power plants. The colloidal stability of the nanofluids was verified by Ultraviolet–Visible spectroscopy, Zeta potential and Dynamic Light Scattering monitoring. The presence of spherical MoS2 nanoparticles resulted in an increase of up to 13% in specific isobaric heat and 6% in thermal conductivity compared to thermal oil. Finally, the efficiency of parabolic trough solar collectors was estimated to increase by 5%, which also favours the decrease of pumping power and the elimination of selective coatings on the absorber tube. To our knowledge, this is the first time that MoS2-based nanofluids are tested as heat transfer fluids in PTCs analysing its implementation in the solar energy application.

Improved performance and surface integrity in finish machining of Inconel 718 with electrically charged tungsten disulphide MQL

This paper presents the results from end milling of Inconel 718 with a newly designed and manufactured minimum quantity lubrication (MQL) delivery system. This involves spraying electrically charged tungsten disulphide (WS2) nano particles dispersed in vegetable oil through pressurised air as a coolant/lubricant. This method improved the cooling and lubrication during machining. Tool life, surface integrity and cutting forces obtained from end milling Inconel 718 with this new system are compared with conventional flood and MQL cooling/ lubrication. The electrically charged WS2 nanofluid was found to increase tool life by ≈10% and significantly improve surface integrity.

Tribological investigation of Molybdenum disulphide nanoparticles and Graphene nanoflakes as lubricant additives in Karanja oil

Tribological investigation of Molybdenum disulphide nanoparticles and Graphene nanoflakes as lubricant additives in Karanja oil

Tribological investigation of molybdenum disulphide nanoparticles and graphene nanoflakes as lubricant additives in Karanja oil

Tribological investigation of molybdenum disulphide nanoparticles and graphene nanoflakes as lubricant additives in Karanja oil

Fractional order simulations for the thermal determination of graphene oxide [formula omitted] and molybdenum disulphide [formula omitted] nanoparticles with slip effects

In this thermal investigation, the mixed free convection Casson nanofluid along with heat transfer effects over a vertical plate is addressed. The thermal radiative phenomenon is also considered to improve the heat transfer rate. For base fluid, the engine oil is assumed for which the thermal enhancement is predicted with the suspension of graphene oxide (GO) and molybdenum disulphide (MoS2) nanoparticles. To construct the fractional model, the partial derivative with respect to time is exchanged by the recent definitions of fractional derivatives namely Atangana-Baleanu (AB) and Caputo-Fabrizio (CF) time-fractional derivative and the Laplace scheme is applied to obtain the solution of governing equations. To enhance the innovation of this article different cases of velocity profiles are examined. The effects of different parameters are examined graphically and numerically by varying the values of parameters. The reported results claimed that the simulations performed via AB-time fractional are more stable as compared to the Caputo-Fabrizio time-fractional approach. The velocity profile declines with increasing the fractional parameters while increasing change in velocity has been observed for Grashof number. The nanoparticles temperature shows a lower change due to volume fraction coefficient.

Biopolymer Nanocomposite Materials Based on Poly(L-lactic Acid) and Inorganic Fullerene-like WS2 Nanoparticles.

In the current study, inorganic fullerene (IF)-like tungsten disulphide (WS2) nanoparticles from layered transition metal dichalcogenides (TMDCs) were introduced into a poly(L-lactic acid) (PLLA) polymer matrix to generate novel bionanocomposite materials through an advantageous melt-processing route. The effectiveness of employing IF-WS2 on the morphology and property enhancement of the resulting hybrid nanocomposites was evaluated. The non-isothermal melt–crystallization and melting measurements revealed that the crystallization and melting temperature as well as the crystallinity of PLLA were controlled by the cooling rate and composition. The crystallization behaviour and kinetics were examined by using the Lui model. Moreover, the nucleating effect of IF-WS2 was investigated in terms of Gutzow and Dobreva approaches. It was discovered that the incorporation of increasing IF-WS2 contents led to a progressive acceleration of the crystallization rate of PLLA. The morphology and kinetic data demonstrate the high performance of these novel nanocomposites for industrial applications.

Effect of epoxidation and nanoparticle addition on the rheological and tribological properties of canola oil

The paper investigates the lubricating properties of epoxidised canola oil. The epoxidation is carried out to decrease the unsaturated bonds present in canola oil. Further, metal dichalcogenide nanoparticles (molybdenum disulphide and tungsten disulphide) are mixed in modified canola oil and their effect on rheological and tribological properties is evaluated. The tribological investigation is carried out on a pin-on-disc tribometer with aluminium alloy and steel as tribopairs. The rheological properties of nanofluids have been studied. It is observed that the modification of the canola oil improves the tribological properties of virgin canola oil. The addition of nanoparticles into the modified canola increases the viscosity of the oil with a 1 wt% concentration of nanoparticles. Further, enhancement in the tribological properties is observed with the addition of nanoparticles. A maximum of 54.6% and 30% decrease in coefficient of friction is observed with the use of tungsten disulphide and molybdenum disulphide nanoparticles, respectively.

Tribological response of polycarbonate and acrylonitrile butadiene styrene blends containing fixed amounts of Kevlar fibre and molybdenum disulphide with varying quantities of betel nut powder

In this study, the composites with incorporation betel nut powder at three levels (10, 18 and 25%) in Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) matrices having Kevlar Fibres (KF) and Molybdenum Disulphide (MoS2) nano particles in fixed amounts are looked into for their tribological characteristics. The effect of hardness, surface roughness and density was evaluated. FTIR and X-ray diffraction (XRD) studies have been carried out to identify the phases. The effects of load on the slide wear loss and coefficient of friction of the composites were determined using Pin on Disc set up. The wear test pertaining to the betel nut bearing (BNP) composites were compared with those of betel nut free ones i.e. PC/ABS/KF/MoS2. The results revealed that with increase in load, the wear loss increases. Further with increase in betel nut powder concentration from 10% to 25% there is a decrease in wear loss as well as coefficient of friction. The surface morphology of the worn surface were examined using Scanning Electron Microscopy (SEM) which revealed higher plastic deformation, debris formation and furrowing in BNP free systems compared to betel nut bearing ones.

Hydrothermally prepared nickel disulphide nanoparticles with enhanced areal capacitance

In this study, mesoporous nickel disulphide (NiS2) nano-particles have been successfully prepared using hydrothermal method. Phase formation and functional groups were identified by the high-resolution X-ray diffractometer (HR-XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. Energy band gap of prepared NiS2 nanoparticles has been studied by diffuse reflectance spectroscopy. FESEM and N2 adsorption–desorption analysis affirmed that surface of the NiS2 nanoparticles is rough with large pore diameter 6.46 nm. Electro-catalytic properties of NiS2 have been analysed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry technique in 1 M aqueous LiOH electrolyte. Electrochemical characterization affirmed that NiS2 has minimum charge transfer resistance (Rct) value of 3.84 Ω with enhanced areal capacitance 9.23 F cm−2 which showed 87% cyclic stability.

Investigation of Selected Polymer Composite-Aluminum Oxide Coating Tribological Systems

The tribotesting of friction systems requires discussion on proper selection of its conditions and data presentation. System tribology is based, for example, on analysis of the friction contact, the roughness of the cooperating surfaces, and the wear rate of the rubbing elements or coefficient of friction in relation to the sliding distance. Friction pairs, consisting of an aluminum alloy sample with an oxide layer (Al2O3) with and without the addition of inorganic fullerenes like tungsten disulphide (IF-WS2) nanoparticles on its surface cooperating with a counter-sample made of polymer composites prepared on the basis of phenol-formaldehyde resin with different fillers, were tested using a device with a pin-on-plate friction pair system. The results of the experiments showed sufficient durability of the Al2O3 and Al2O3/IF-WS2 oxide coatings in combination with the polymer composite. It was found that resin fillers such as cotton fibers, jute fibers, molybdenum disulphide (MoS2) or graphite (C) influence the friction behavior of the tribological pairs. Although the values of the coefficient of friction obtained in the tests were quite high, their course during the tests ensured stable cooperation of the aluminum coating/polymer composite friction pair on a 15 km distance, under a load of 0.5 MPa. The lowest coefficients of friction were obtained for oxide layers formed on aluminum combined with a polymer composite filled with cotton fibers and graphite. These studies provide information on the tribological properties of commercially available polymer composites cooperating with the produced oxide coatings, supplementing the available literature with the results of research on new, so far unexplored tribological partners. Microscopic investigation of the structure and morphology of the formed surface oxide layers and also microgeometry studies of both the friction elements were used to better understand the obtained research results.