Energy Dispersive X-ray Spectroscopy Techniques Research Articles

Analysis of tribological behavior, pin temperature, and surface roughness of a brake pad material with nano coating

The present work is concentrated on the novel multi-nano particle coating of CoNiCrAlY matrix on brake pad material. The tribological behavior of plasma sprayed CoNiCrAlY particle composite coating with nano inert particles like ZrO2, Al2O3, and AT40 were compared. A comparison was made with respect to structure and morphology of coating. The coatings were characterized with Scanning electron microscopy(SEM) and Energy dispersive X-ray spectroscopy(EDAX) technique. The tribological performance of these coatings were studied using pin-on-disc test rig under dry sliding conditions. The wear study revealed CoNiCrAlY+nano Al2O3 particle coating showed better specific wear rate compared to ZrO2 and AT40 composite coating. The observed tribological behaviour is very much influenced by the ability of nano particles to get distributed in the CoNiCrAlY matrix. The CoNiCrAlY coating with nano particles showed significant specific wear resistance of brake pad material. They coated samples also resulted in minimum rise in pin temperature. This is attributed to the homogeneous distribution of nano particles in the coating. These composite coating also showed lower coefficient of friction values. Although referring to other simplified and extreme conditions, the results obtained provides a new window for using nano hard coatings to enhance the life and efficiency of the commercially available four-wheel vehicle brake pad.

Corrosion behaviors of single-layer and double-layer nickel alloy coatings fabricated by arc spraying and high-velocity oxy-fuel

This study investigates single-layer and double-layer thermally sprayed nickel alloy coatings (bond and top coatings). Ni-5 wt% Al and Ni-20 wt% Cr, were used as bond coatings, whereas highly alloyed Ni-based coatings, Hastelloy C276 or Inconel 625, were used as top coatings. Arc spraying (A) and high-velocity oxy-fuel (HVOF) techniques were used to create the coatings on a 304 stainless steel substrate. The samples were studied by performing potentiodynamic polarization tests in a 20 vol% H2SO4 solution at room temperature. The scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and wavelength dispersive X-ray spectroscopy (WDS) techniques were used to investigate the microstructure and chemical composition of the coatings. The arc sprayed coatings are composed of a lamellar microstructure with low porosities, unmelted particles, and high oxides at the intersplats. A uniform and compact coating with minimal oxides and porosity was achieved for all coatings via HVOF technique. In single-layer coatings, arc spray coating surpasses HVOF coating owing to its oxide layers, which impede sulfuric solution penetration and bolster resistance against electrolyte infiltration. Double-layer coatings, comprising a bonding layer and a top coating, effectively alleviate microgalvanic corrosion between layers when using the same thermal spray method.

Deposition of nickel-titanium coating on stainless steel 316L by direct current sputtering for bio-implants: Electrochemical, microstructural, and morphological investigations

In general, the application of coatings provides vital protection for medical devices with a host of beneficial properties such as biostability and biocompatibility, chemical barrier, and micro-encapsulation. In the current work, a nickel-titanium (NiTi) system was deposited on stainless steel (SS316L) by the direct current sputtering (DCS) technique to estimate the corrosion behavior in the simulated body fluid (SBF) at 37 °C. The characterization of the coating layer was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDX) techniques to know the phases, elemental composition, and structure of the coating that indicated the formation of the Ni3Ti phase as a flake-shaped structure with 2.6 and 0.4 wt% of Ni and Ti, respectively. The results of atomic force microscopy (AFM) showed a decrease in surface roughness from 25.2 to 11.05 nm after coating due to a decrease in the mean diameter of particles from 710.8 to 579.9 nm after coating. The data corrosion test showed the change of corrosion potential to a more noble value with minimizing the corrosion current density as well as the improvement of resistance after coating from 6.91 × 103 to 25.49 × 103 Ω.cm2 to get protection efficiency equal to 73.9 %. In a cyclic polarization test, it can be seen that the passivity region shifts to lower current density values. Microhardness was also measured to show an increase from 187 to 366 HV due to the selected technique of coating that gives more hardness; the measured wettability did not change the contact angle of the uncoated specimen to keep it at 90°; and finally, the histological analysis did not show any severe infection or inflammation. All these observations can suggest the NiTi coating for bio-applications.

Microfacies and mineralogical analyses of the late cretaceous carbonate rocks from The Central Benue Trough, Nigeria

The Cretaceous limestone facies from Yandev section in the central Benue Trough, Nigeria constitutes parts of the potential reservoirs and sources rocks for petroleum prospects in the basin. The central Benue Trough is the least studied basin among its contemporaries due to lack of subsurface data. Detailed mineralogical, facies analysis and diagenesis of these carbonate rocks in the basin have not received significant study. The aim of this study was to employed multifaceted methodology such as sedimentological, facies analysis petrographic and geochemical approaches which was lacking in previous research in the trough. The sedimentological analysis was done to evaluate fabrics grain sizes, and lithology types. For petrographic analysis, thin sections were prepared and examined under a petrographic microscope and categorized according to Dunham's classification. Geochemical analysis involved X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope - energy dispersive X-ray spectroscopy (SEM-EDX) techniques to unveil mineralogical, oxide, and elemental compositions. The sedimentological results revealed light to dark grey medium to fine-grained limestone facies with intercalation of dark grey shales and siltstones. The XRD mineralogy data, revealed calcite (60.00 - 64.10%), quartz (14.30 - 51.00%), albite (12.30 - 19.00%), and chlorite (6.30 - 8.10%). Microfacies results revealed distinct sandy bioclastic wackstone and sparitic intraclastic packstone, as well as micritic intraclastic wackestone and sparitic bioclastic packstone. SEM images highlighted the intricate composition, including elongated structures, whites and dark spots suggesting varying conditions of deposition. Elemental analysis through EDX emphasized significant proportions of carbon, oxygen, sodium, potassium, calcium, silicon, aluminum, iron, and magnesium. Based on sedimentological, biofacies, lithofacies and geochemical evidence we infer that the carbonate sediments were mainly deposited in a shallow marine depositional environment (inner to outer neritic).

Preparation and Anti-Icing Properties of Zirconia Superhydrophobic Coating.

Zirconia (ZrO2) is a ceramic material with high-temperature resistance and good insulating properties. Herein, for the first time, the surface of ZrO2 was modified with docosanoic acid (DCA) to improve its self-cleaning and hydrophobic properties. This surface modification transformed the surface of ZrO2 from hydrophilic to superhydrophobic. A two-step spraying method was used to prepare the superhydrophobic surface of ZrO2 by sequentially applying a primer and a topcoat. The primer was a solution configured using an epoxy resin as the adhesive and polyamide as the curing agent, while the topcoat was a modified ZrO2 solution. The superhydrophobic surface of ZrO2 exhibited a contact angle of 154° and a sliding angle of 4°. Scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and other analytical techniques were used to characterize the prepared zirconia particles and their surfaces. Moreover, results from surface self-cleaning and droplet freezing tests showed that DCA-modified ZrO2 can be well combined, and its coatings show good self-cleaning and anti-icing properties on TA2 bases.

Exploring secondary optical transitions: a study utilizing the DITM method, and enhanced photocatalytic properties in Ni-doped CuSe

This study explores the simultaneous presence of two metal ions of Nickel (Ni) and Copper (Cu) on the formation of a metal selenide (Ni-doped CuSe) in an alkaline environment. The impact of Ni ions on creating the second optical transitions is investigated. Different concentrations amounts of Ni ions (0.01, 0.02, and 0.03 mol) are utilized to produce Ni-doped CuSe semiconductor thin films through a chemical solution deposition method with deposition times varying from 3 to 6 h. Absorbance spectra are employed to determine the band-gap, while Field Emission Scanning Electron Microscopy is utilized for morphological analysis. Structural and elemental analyses are conducted using X-ray Diffraction and Energy Dispersive X-ray Spectroscopy techniques. Additionally, a relatively innovative approach for determining the optical transitions, termed the Derivation Ineffective Thickness Method (DITM), is employed. DITM eliminates the need for thin film thickness and assumptions about the type of transition (direct or indirect) for band-gap calculation. Moreover, a comparison is made between the band-gap obtained from the Tauc model and the transitions obtained by DITM method. Furthermore, it is demonstrated that the optical transitions exhibit two distinct band-gaps associated with nickel selenide (NiSe) as second transition and copper selenide (CuSe) as fundamental transition. The presence of Ni is also found to enhance crystal quality. The study also briefly explores the improved photocatalytic properties of CuSe in the presence of Ni.

Advancing cobalt ferrite-supported activated carbon from orange peels for real pulp and paper mill wastewater treatment

The utilization of agriculture waste-based adsorbents in the treatment of real industrial wastewater represents an unexplored frontier with significant potential. In this study, the cobalt ferrite-supported activated carbon derived from orange peels (CF40-AC) was used as a magnetic adsorbent for the treatment of real pulp and paper mill effluent (PPME). Detailed insights into the properties and functionalities of the CoFe2O4-AC adsorbent were obtained through an accurate characterization analysis that included X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), BET and pore size histogram techniques. Both pure activated carbon (AC) and CF40-AC displayed excellent textural properties with surface area (SBET) equal 2014 and 1345 m2.g−1, respectively. TEM and SEM images display that the magnetic ferrites were well dispersed on the surface of AC. Following the characterization process, the CoFe2O4-AC adsorbent was evaluated for its ability to remove several key pollutants from PPME, including chemical oxygen demand (COD), total dissolved solids (TDS) and turbidity. Moreover, various operational parameters, such as pH, adsorbent dosage, contact time, and stirring rate, were investigated to achieve optimal contaminants removal rates. Remarkably, the CoFe2O4-AC adsorbent demonstrated highly efficient removal rates, with 86.9%, 59,9% and 93.1% for COD, TDS and turbidity, respectively, under optimal conditions (pH 7, adsorbent dose 0.4 gm, contact time 60 min, and stirring rate 150 rpm). The CoFe2O4-AC composite material exhibits promising potential for multiple applications reached 5 cycles without a significant loss in its adsorption or functional properties over successive uses. These results favor the promising potential of CoFe2O4-AC as a sustainable and efficient solution for addressing wastewater treatment challenges in the pulp and paper industry, contributing to both environmental protection and resource conservation.

Investigation on thermoelectric properties of SnSe thin films as prepared by RF magnetron sputtering

In this work, we investigated the thermoelectric properties of SnSe (Tin Selenide) thin films onto SiO2/Si-wafer substrates as prepared by RF (radio frequency) magnetron sputtering technique. The sputtering conditions used base pressure below 5.5 10-4 Pa and working pressure at 0.93 Pa within the Ar atmosphere as a flow rate fixed 40 sccm. The RF sputtering power was applied at 80 W and sputtering time for 30 min. After thin film deposition, as-deposited thin films were annealed by the vacuum annealing method at 300-450 oC. The crystal structure, morphology and film thickness, and atomic composition of SnSe thin film were carried out by X-ray diffraction (XRD), the field emission scanning electron microscope (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques, respectively. The thermoelectric properties (electrical resistivity; ρ) and Seebeck coefficient; S) were measured by the ZEM-3 method to calculate the power factor (PF) value. The results showed that the as-deposited thin films had improved the crystallography of SnSe from amorphous to crystalline phases after thin films were annealed at a temperature range of 300-400 oC. At room temperature, the maximum power factor of 0.35 mW m˗1 K˗2 (ρ = 202 mΩ m and S = 165 μV K˗1) could be found to estimate the dimensionless Figure of Merit (ZT) values around 0.44 for annealing thin film sample at 400 oC.

Microplastics in indoor deposition samples in university classrooms

The pollution caused by microplastics (MPs) is a growing concern on a global scale, especially considering the significant proportion of time that individuals spend indoors. The contamination in question has the potential to directly impact the human population through exposure to indoor dust and air. This research undertook a comprehensive analysis of the indoor deposition of MPs in university classrooms, employing various investigative tools. The present study aimed to comprehensively analyze the physical and chemical properties of MPs found in university classrooms. Analyzing samples under a stereomicroscope, the predominant MPs were identified as fibers of varied colors, mainly attributed to clothing. Sizes of these MPs varied significantly across different classrooms, with a general average size range of 120–2222 µm. The observed morphological changes in MPs, including cracks and grooves, hint at potential degradation into nanosized plastics over time. This observation raises concerns about increased concentrations of nanoplastics in indoor environments. Using µRaman analysis, eleven types of MPs were identified, potentially originating from clothing, shoes, and stationery. The majority of MPs were polyamide 6, polypropylene, and polyamide 12. The scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM–EDX) technique unveiled the elemental composition of the MPs, with carbon, fluorine, and oxygen being dominant. The findings align with past studies but highlight the need to understand MPs' structural components and any possible contaminants. Compared to existing literature, this study adopts a comprehensive methodological approach combining optical microscopy, µRaman, and SEM–EDX, enriching the knowledge on indoor MP deposition and aiding future research directions.

Long-term corrosion of copper alloys in the soil: new aspects of corrosion morphology in archaeological vessels from south-western Iran

A group of copper-based objects excavated at Deh Dumen cemetery, in south-western Iran, was studied and analysed to examine the long-term corrosion morphology and mechanism in the soil burial environment. For this purpose, twenty-two samples from twenty-one copper-based vessels were studied and analysed using X-ray diffraction, scanning electron microscopy—energy dispersive X-ray spectroscopy, micro-Raman spectroscopy and metallography techniques. The results of the analyses showed that the majority of vessels are made of tin bronze, along with two arsenical copper samples. The extent of corrosion observed ranges from very thin corrosion crusts to thick crusts and entirely corroded structures. These three identified corrosion morphologies display a multi-layered corrosion stratigraphy as well as the preserved limit of the original surface. The corrosion crusts include internal tin-rich and external copper-rich layers, and the main corrosion mechanism for the formation of multi-layered corrosion crusts is decuprification or selective dissolution of copper during the long-term burial time in a moderately Cl-contaminated soil. The three identified corrosion morphologies are similar to the previously published morphologies, but some clear deviations are apparent and are discussed here.

Novel electrochemical sensing platform for accurate detection of benzylpenicillin based on a graphene oxide-manganese ferrite modified carbon paste electrode

Antibiotic overuse and environmental disregard result in water supply contamination, caused antibiotic resistance. Given the global health concern, developing a sensitive, simple, and low-cost antibiotic sensor is critical. In this study, graphene oxide was incorporated with MnFe2O4 to modify the carbon paste electrode (CPE) as a new electrochemical platform for detecting benzylpenicillin, the widely used antibiotic. A comparative chemical and structural characterization of the synthesized MnFe2O4 nanoparticles (NPs) and GO/MnFe2O4 nanocomposites (NCs) verified that the successful integration of spherical particles of MnFe2O4 NPs onto GO nanosheets produces a rough surface. Furthermore, the structure and electrochemical characterization of the developed GO/MnFe2O4/CPE were conducted via field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and impedance spectroscopy (EIS) techniques. The proposed electrode presented enhanced active surface area and electrocatalytic performed due to the superior features of the used modifiers, which work synergistically. The GO/MnFe2O4/CPE demonstrated a high-performance benzylpenicillin sensing platform, giving a detection limit of 145 nM and sensitivity of 15.16 μAμM-1cm−1 as measured by differential pulse voltammetry (DPV) within two dynamic ranges of 1–100 μM and 100–1000 μM. The created sensor was applied as a practical apparatus for the electrochemical determination of benzylpenicillin in water samples.

A simple and highly efficient approach towards the degradation of methylene blue and study the impact of degraded water on seed germination of cicer arietinum

The scarcity of fresh air, drinking water, and soil is a matter of serious concern worldwide owing to the presence of organic pollutants in the environment. The organic dye, such as methylene blue (MB) have enormous toxic effects on the environment and human health. Therefore, the degradation of non-biodegradable dyes is very important to reduce toxicity in water and-a step towards waste water management systems. This paper focuses on the degradation of non-biodegradable MB dye using carbon quantum dots (CQDs). CQDs were synthesized by a microwave irradiation method using citric acid and L-cysteine as precursor and confirmed by X-Ray Diffraction (XRD), Raman Spectrum, Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive x-ray (EDX) spectroscopy techniques. The optical properties of the synthesized CQDs of 2.56 nm, were investigated by UV-visible spectroscopy technique and the absorption peak appeared at 340 nm which corresponding to n → π* transition. In photoluminescence (PL) spectra analysis, the highest emission peak was obtained at 440 nm when excited at 345 nm. The synthesized CQDs were used for the dye degradation of MB in distilled water and degradation percentage was calculated and found to be 99.17% in 90 min under UV light irradiation. Also, studied the impact of degraded water in seed germination of Cicer arietinum (black gramme) and calculated the seed germination growth rate in degraded water was found to be 15%–20% more than the seed germination growth rate in MB containing dye water.

Functionalized cellulose nanocrystals extracted from date pits as agricultural waste for the efficient remediation of molybdenum from groundwater: Performance and mechanistic studies

The adsorption technique has proven to be an excellent option for treating contaminated water. This work was designed to investigate the efficient remediation of molybdenum (Mo(VI)) from groundwater by using a novel adsorbent composed of date pits (DP) modified by manganese oxide/cellulose nanocrystal (CNC) composite (MnO2/CNC@DP). The physicochemical properties of the adsorbent were examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope with energy-dispersive X-ray spectroscopy techniques (SEM/EDX), X-ray diffraction (XRD), and transmission electron microscopy (TEM) to study the functional group on the adsorbent surface, surface morphology and chemical composition, and the crystallinity behavior. The performance of prepared (MnO2/CNC@DP) toward Mo(VI) was studied using synthetic solutions and real groundwater samples. Also, the effect of pH, temperature, and initial Mo concentration on the adsorption process was investigated. Moreover, various adsorption isotherm models were calculated, and the thermodynamics of adsorption was studied. The recovery experiments for Mo(VI) saturated MnO2/CNC@DP were conducted by using acidic and alkaline solutions. At the optimum pH of 2, the adsorption capacity increased with increasing the initial concentration of Mo(VI), and Qmax was 30 mg/g at 35 °C. The removal of Mo(VI) from real groundwater was 88.42% The negative values of Gibbs energy (ΔG°) demonstrated that the adsorption is spontaneous, and the experimental data followed the Langmuir isotherm model. Moreover, Mo(VI) can be desorbed from the MnO2/CNC@DP surface by using 1.0M HCl. The proposed mechanisms for the adsorption of Mo(VI) by MnO2/CNC@DP were dominated by electrostatic attraction and inner-sphere complexation. As a result of the research, MnO2/CNC@DP is a promising adsorbent with a high potential for removing Mo(VI) from groundwater. Furthermore, This research provides new knowledge into the modification of date pits using different metal oxides/cellulose nanocrystal particles. Furthermore, the results suggest an excellent chance of employing the efficiently produced adsorbent MnO2/CNC@DP for sustainable groundwater treatment from additional contaminants.

Zirconium oxide thin films deposited via DC magnetron sputtering: corrosion and morphological investigation

Purpose The purpose of this study is to investigate the structural, surface roughness and corrosion properties of the zirconium oxide thin films deposited onto SS304 substrates using the direct current (DC) magnetron sputtering technique. Design/methodology/approach DC sputtering at different powers – 80, 100 and 120 W – was used to deposit ZrO2 thin films onto different substrates (Si/SS304) without annealing of the substrate. Atomic force microscope (AFM), energy-dispersive X-ray spectroscopy (EDS), Tafel extrapolation and contact angle techniques were applied to investigate the surface roughness, chemical compositions, corrosion behavior and hydrophobicity of these films. Findings Results showed that the thickness of the deposited film increased with power increase, while the corrosion current decreased with power increase. AFM images indicated that the surface roughness decreased with an increase in DC power. EDS analysis showed that the thin film has a stoichiometric ZrO2 (Zr:O 1:2) composition with basic uniformity. Water contact angle measurements indicated that the hydrophobicity of the synthesized films decreased with an increase in surface roughness. Originality/value DC magnetron sputtering technique is infrequently used to deposition thin films. The obtained thin films showed good hydrophobic and anticorrosion properties. Finally, results are compared with other deposition techniques.

Cross-linked polymer film on copper stubs as a reusable substrate enabling imaging and quantitative analyses of aluminosilicate particles

Access issues to potable waters around the planet is the motivation for research in desalination technologies. One class of materials that is a research focus for desalination membranes are zeolites that are comprised of silicon (Si), aluminum (Al), and oxygen, and have structures that include regular pores of varying sizes dependent on the type of zeolite. A motivation for this study was to enable characterization of non-conductive materials containing Si or Al (e.g., zeolites) using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. To avoid significant background signals directly overlapping with these samples, common sample supports and preparation protocols involving Al or Si were precluded. Cross-linked polymer coatings applied via spin coating onto polished copper (Cu) stubs are shown to be durable for reuse even with the use of aggressive cleaning techniques between samples. SEM and EDS analyses of Cu stubs were performed before and after applying the polymer coating, after drop-cast application of zeolite particles and after their subsequent removal by sonication-based techniques. The data from those trials confirmed there was no background signal from Si or Al and no cross-contamination between samples during these analyses, enabling quantitation of Al and Si in the samples.

Green biosynthesis of bimetallic selenium-gold nanoparticles using Pluchea indica leaves and their biological applications.

Increasing bacterial resistance and the negative impact of currently used antibacterial agents have produced the need for novel antibacterial agents and anticancer drugs. In this regard, nanotechnology could provide safer and more efficient therapeutic agents. The main methods for nanoparticle production are chemical and physical approaches that are often costly and environmentally unsafe. In the current study, Pluchea indica leaf extract was used for the biosynthesis of bimetallic selenium-gold nanoparticles (Se-Au BNPs) for the first time. Phytochemical examinations revealed that P. indica leaf extract includes 90.25mg/g dry weight (DW) phenolics, 275.53mg/g DW flavonoids, and 26.45mg/g DW tannins. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) techniques were employed to characterize Se-Au BNPs. Based on UV-vis spectra, the absorbance of Se-Au BNPs peaked at 238 and 374nm. In SEM imaging, Se-Au BNPs emerged as bright particles, and both Au and Se were uniformly distributed throughout the P. indica leaf extract. XRD analysis revealed that the average size of Se-Au BNPs was 45.97nm. The Se-Au BNPs showed antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis, with minimum inhibitory concentrations (MICs) of 31.25, 15.62, 31.25, and 3.9μg/mL, respectively. Surprisingly, a cytotoxicity assay revealed that the IC50 value toward the Wi 38 normal cell line was 116.8μg/mL, implying that all of the MICs described above could be used safely. More importantly, Se-Au BNPs have shown higher anticancer efficacy against human breast cancer cells (MCF7), with an IC50 value of 13.77μg/mL. In conclusion, this paper is the first to provide data on the effective utilization of P. indica leaf extract in the biosynthesis of biologically active Se-Au BNPs.

Electrochemical Sensor for Tryptophan Determination Based on Trimetallic-CuZnCo-Nanoparticle-Modified Electrodes.

The superior properties of electrodeposited trimetallic CuZnCo nanoparticles, arising from the synergistic effect of combining the unique features of metallic components, were confirmed using voltametric measurements. The surface morphology and structure of the as-prepared electrocatalysts were determined using scanning electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy techniques. Here, the trimetallic CuZnCo nanoparticles were synthesized as a powerful redox probe and highly efficient signal amplifier for the electrochemical oxidation of tryptophan. Differential pulse voltammetry studies showed a linear relationship with a tryptophan concentration of 5-230 μM, and the low detection limit was identified at 1.1 μM with a sensitivity of 0.1831 μA μM-1 cm-2.

Electrochemical deposition and characterisation of NiTi alloy coatings for better corrosion protection

ABSTRACT The present study reports the electrochemical deposition and characterisation of Nickel-Titanium (NiTi) alloy coatings on mild steel (MS) from citrate bath having nickel sulphate and titanium oxysulphate as salts, tri-sodium citrate as complexing agent and glycerol as the brightener. Bath composition and operating variables were optimised by the conventional Hull cell method for bright and uniform coating. NiTi alloy coatings were developed at varied current densities (1.0 A/dm2 to 4.0 A/dm2), keeping pH = 4.0. The corrosion behaviours of NiTi alloy coatings were evaluated by electrochemical AC and DC methods in a 3.5 per cent sodium chloride solution. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) techniques were used to study the phase structure, surface morphology and chemical composition of the coatings, respectively. The observed facts stand to the reason that the bath follows induced type co-deposition in the range of current density studied. Corrosion studies validated that NiTi alloy coating deposited at 4.0 A/dm2 is the most corrosion-resistant among all other current densities. This highest corrosion stability of NiTi alloy, corresponding to 4.0 A/dm2 is attributed to high wt.% of Ti (i.e. 3.5%). The decrease in corrosion rate towards high current density was analysed and discussed.

Synthesis and characterization of Ag-doped CdS quantum dots for enhanced photovoltaic performance of quantum dot sensitized solar cells

In this work, Ag-doped and undoped CdS quantum dots (QDs) were prepared via successive ionic layer adsorption and reaction (SILAR) technique, followed by their characterization. The synthesized QDs were employed in the devices based on iodide/triiodide (I−/I3−) and polysulfide (Sx2−/S2−) electrolytes, while carbon (C) and platinum (Pt) were used as counter electrodes (CEs). The structural properties of the synthesized QDs were examined using X-ray diffraction (XRD), while to analyze the elemental composition of the samples, energy-dispersive X-ray (EDX) spectroscopy technique was employed. To study absorption properties, UV–Visible spectroscopy was performed. The influence of Ag on passivation of defects in CdS QDs was investigated via photoluminescence spectroscopy. Photovoltaic performance and impedance spectroscopic measurements on the fabricated QDSSCs were made under an AM1.5G illumination and dark, respectively. The photovoltaic studies on the devices revealed an increase of efficiency by 131 %, 161 %, 151 %, and 93 % for Ag–CdS QDs/Iodolyte/Pt, Ag–CdS QDs/Polysulfide/Pt, Ag–CdS QDs/Iodolyte/C, Ag–CdS QDs/Polysulfide/C type devices, respectively. The doped device with a polysulfide electrolyte and C as counter electrode (CE) revealed superior performance, exhibiting an efficiency of 1.72 %, followed by the doped polysulfide-based device with Pt as CE, revealing 1.67 % efficiency. The stability test conducted on the fabricated devices demonstrated a long-term stability for the doped device containing polysulfide electrolyte and C as CE, retaining 80 % of its initial efficiency for 12 days, and then falling to 0 % in 22 days. Moreover, the impedance spectroscopic measurements revealed lowest series resistance (Rs) and Series Capacitance (Cs) for the superior performance device.

Comparative study on physicochemical characteristics of atmospheric microplastics in winter in inland and coastal megacities: A case of Beijing and Shanghai, China

Atmospheric microplastics (MPs) have received global attention across various sectors of society due to their potential negative impacts. This study aims to understand the physicochemical characteristics of MPs in inland and coastal megacities for raising awareness about the urgent need to reduce plastic pollution. Laser Direct Infrared Imaging (LDIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) techniques were employed to characterize atmospheric MPs in megacities (inland megacity Beijing and coastal megacity Shanghai) in China, focusing on their physicochemical characteristics, including compositional types, number concentration, morphology, size, possible sources, and potential health risks. The LDIR analysis identified sixteen different types of MPs present in the atmospheres of Beijing and Shanghai. The number concentration of atmospheric MPs in Beijing (3.0 items/m3) is 1.8 times that of Shanghai (1.7 items/m3). The study found that the variations in MP pollution between Beijing and Shanghai are influenced by the urban industrial structure and geographical location. Morphological analysis indicates that fragment MPs have the highest relative abundance in Beijing, while fibrous MPs dominate the atmosphere of Shanghai. Additionally, the study assessed the potential health risks of atmospheric MPs to urban residents. The results suggest that residents of Beijing face more severe health risks from atmospheric MPs compared to those in Shanghai. These findings underscore the urgency to address the issue of atmospheric MPs and provide crucial evidence for the formulation of relevant environmental and health policies.