Cobalt Content Research Articles

Effect of substituting manganese by few cobalt content in the transport properties of Pr/Ca based manganite

Effect of substituting manganese by few cobalt content in the transport properties of Pr/Ca based manganite

Seasonal Variation of Heavy Metals in the Bivalves of a Major Fish Landing Centre in Mumbai

One of the most prevalent environmental contaminants found in aquatic ecosystems and its associated biota is considered to be heavy metals. The current study evaluated the heavy metal concentrations of Copper (Cu), Iron (Fe), Cadmium (Cd), Zinc (Zn), Manganese (Mn), Cobalt (Co), Chromium (Cr), Arsenic (As), Nickel (Ni), and Lead (Pd) in the soft tissues of M.casta and Paphia malabarica species seasonally for one year. The soft tissue of the two species were digested using a microwave digestion system (CEM-MARS-5) using nitric acid and perchloric acid. Evaluation of Cu, Ni, Cr, Mn, Co, Fe, and Zn was done using ICP-OES while for estimation of Pd, Cd and As, ICP-MS was used. During the study, Fe, Mn and Zn content dominated the whole soft tissues of both species. The findings demonstrated that the pre-monsoon season had higher amounts of the most examined heavy metals, whereas the monsoon season had the lowest quantities of these metals in the soft tissues of both species.

Electrochemical applications of CdO-Co-ZnO nanocomposites, their synthesis and characterization reveal their multifunctional abilities

In this study, we investigated the electrochemical catalysis potential of hybrid nanocomposites containing CdO, Co and ZnO nanocomposites, as opposed to Zn-O doped Co nanocomposites, have weaker Coulomb interactions due their ionic bonds. Because CdO and Co form a covalent bond, Co interacts more strongly with O than Zn. In order to reduce nanoparticle crystallinity, oxygen defects improve the interaction between −O and oxygen defects in the lattice. From SEM micrographs, it appears that CdO does not completely change under the influence of dopants. It can be seen from the SEM image that both materials have very tightly packed particles. The Co and CdO dopants in ZnO nanocomposites prevent them from absorbing a large range of visible wavelengths. It is more energy-dense for nanocomposites with 5.28 eV to compare to 5.14 eV nanocomposites. The fact that CdO matrix has a tuneable bandgap is evident since different types of dopants are used in its manufacture. There are at least three distinct absorption modes in Co nanocomposites doped with CdO, around 450, 498, and 676 cm−1. In addition to its absorption from 450 cm−1 and 498 cm−1 vibrational modes, Co-O stretching absorption along the [101] plane has also been observed at 676 cm−1. As a method of studying charge carriers, photoluminescence spectroscopy is usually used. This method can be used to analyze electron-hole pairs (e−/h+) formed by semiconducting particles. It is in the blue emission range between the luminescence band of 615 nm and the valence band of 635 nm. With increasing cobalt and zinc concentrations, CdO nanomaterials lose their remanent magnetization. CdO has been demonstrated to have significant coercive effects in both pure and additively incorporated solutions regardless of their anisotropic, morphological, porosity, and particle size distribution. Electrochemical impedance spectrum measurements were conducted between 100 kHz and 0.01 Hz. According to the Nyquist plot, purity CdO, CdO doped Co, and CdO doped ZnO nanocomposites show a high frequency resistance to charge transfer. Nanocomposites that contained CdO doped Co & ZnO were exposed to UV light for 120 min to remove the solution. The degradation of MO is virtually nonexistent when no photocatalyst is present, but with a photocatalyst, degradation can reach 92.56 %.

PRODUCTION OF SYNTHETIC HYDROCARBONS USING COBALT CATALYSTS BASED ON ZSM-5 ZEOLITE

In this work, cobalt catalysts based on zeolite ZSM˗5 were prepared by the triple impregnation method and chemically analyzed. Zirconium dioxide was used as a promoter (3 wt. %). Chemical analysis of the elemental composition and structure of the obtained catalysts was carried out using scanning electron microscopy. It is shown that the elemental composition of the catalysts with satisfactory accuracy corresponds to their given composition. Experiments for catalytic tests of the prepared catalysts were carried out on a laboratory Fischer-Tropsch synthesis unit and synthetic hydrocarbons were obtained. Comparative characterization of activity of the obtained catalysts with cobalt content of 10 % and 20 % has been carried out, dependence of carbon monoxide conversion and selectivity with respect to formation of gas hydrocarbons and yield of liquid products on temperature has been studied.

Heavy Metals Contamination in Snow Cover of Pavlodar (Kazakhstan)

A study of the concentration of heavy metals in snow cover was carried out in Pavlodar in the area of influence of the Pavlodar Petrochemical Plant and other industrial facilities. Significant excesses of background concentrations of manganese, chromium, vanadium and other metals were detected. The distribution of metals in the snow cover showed that the elements have high values near the oil refinery and decrease at a distance of 700 m. The possible influence of other industrial enterprises and the direction of winds from CHP-3 are also noted. Manganese and barium show more stable values, and chromium, zinc, lead and cadmium have increased concentration near JSC “Kaustik”. The total concentration of manganese, strontium, cobalt and arsenic varies slightly across all sites, indicating uniform contamination by these substances. Lead is highest in industrial areas and in populated areas with highways. Aluminum and iron are widespread, with the lowest values in the Zhanaul village at a distance of 3 km from the Petrochemical Plant. The results of the study highlight the importance of controlling and monitoring heavy metal pollution and the need to take measures to reduce anthropogenic impacts on the natural environment.

Preparation of Bimetallic CoFe@CSC-700 Carbonated Microspheres and Activated Peroxymonosulfate for Degradation of Levofloxacin

The exploration of efficient, low-leaching, and recyclable transition-metal-based catalysts is of great importance for the removal of pollutants from peroxymonosulfate (PMS) in water purification processes. In this study, a bimetallic CoFe@CSC-700 composite was prepared by an alkaline gel pyrolysis reduction method using chitosan as a forming agent and applied to activate PMS to degrade levofloxacin (LEV). The leaching concentration of both cobalt and iron ions in the CoFe@CSC-700 catalyst was reduced by about 8-fold compared to the monometallic composite pellet catalyst. In addition, the removal efficiency of the CoFe@CSC-700 catalyst can still reach 90% after five cycles, showing good recyclability, recoverability and stability. Both free radical pathways (SO4·−, ·OH, and ·O2−) and non-free radical pathways (1O2) were detected in the oxidation reaction, with free radical pathways as the main contributor. The possible degradation pathways of LEV were proposed by LC-MS tests. Overall, this study provides new insights into the construction of efficient and stable PMS catalysts for wastewater treatment.

Effect of cobalt content on the microstructure, microtexture, and mechanical properties of W-Ni-Fe-xCo alloys during solid-phase-sintering and liquid-phase-sintering

Compared the effect of Co content on the microstructure, microtexture, and mechanical properties of W-Ni-Fe-xCo alloys during solid-phase-sintering and liquid-phase-sintering. The results indicated there is a non-uniform distribution of W and γ phases, accompanied by the presence of little voids during solid-phase-sintering at 1420 °C. Adding Co element enhances the wetting between the W and γ phases, and reduces the liquid-phase-sintering temperature, shrinking the size and quantity of pores. The W phase transforms into ball-shaped particles with completed liquid-phase-sintering at 1440 °C. With increased Co content, W grain size decreases, matrix fraction volume increases, and Cw-w continuity and dihedral angle decrease. The mechanical properties of the alloys improve with sintering temperature and Co content, the tensile strength and elongation reached 989 MPa and 13.7% due to the elimination of holes and the W content increased within γ phase. The relationship among W content in γ phase, strength, elongation, and microhardness with Co content were revealed. The solution strengthening effect increases, which drives the co-deformation of W and γ phases, thereby increasing the strength and elongation. The addition of Co element and the atomic diffusion at high temperature made the fibre microtexture more concentrated.

Cobalt(II) removal with dolomite: Use of radiotracer technique in aqueous solution

Industrial processes have the potential to release cobalt into the environment, and exposure to cobalt in quantities higher than specific amounts can have harmful impacts on living organisms. This study aimed to determine whether natural dolomite from the Thrace region of Türkiye could effectively remove Co(II) from aqueous solutions. Batch studies were conducted to examine the impact of various experimental factors, including adsorbent dosage, initial Co(II) concentration, contact time, solution pH, and temperature. The cobalt concentrations in aqueous solutions were determined by employing 60Co radionuclide as a radiotracer. Experimental results revealed that optimum adsorption conditions were obtained at a solid-liquid ratio of 20 g·L−1, initial Co(II) concentration of 128 mg·L−1, contact time of 120 min, and pH 6 with a maximum adsorption capacity of 2.32 mg⋅g−1. The pseudo-second-order kinetic and Redlich-Peterson isotherm models described the experimental data well. The adsorption process of Co(II) ions on the dolomite was spontaneous and exothermic. The results showed the potential use of dolomite to remove such a toxic metal ion from industrial wastewater.

Residential proximity to toxic metal-emitting industrial sites and toenail metal concentrations in a United States-wide prospective cohort

BackgroundIndustrial facilities across the United States (US) release millions of pounds of toxic chemicals, including metals. Exposure to toxic metals has been associated with adverse health outcomes, but there is limited evidence on the association between living near metal-releasing facilities and the body burden of emitted compounds. ObjectiveTo investigate the association between residential proximity to toxic metal-emitting industrial facilities and toenail metal concentrations and to evaluate whether associations differed by race. MethodsIn a sample of 1556 non-Hispanic Black (32.5%) and non-Hispanic White (67.5%) women from the Sister Study, we used the US Environmental Protection Agency Toxics Release Inventory to identify metal-emitting facilities within 3, 5, and 10 km of participants’ baseline residences. We measured toenail concentrations (μg/g) of arsenic, cadmium, cobalt, chromium, and lead. Using multivariable linear regression, we examined associations between residential proximity to and emissions from metal-emitting facilities and toenail metal concentrations, stratifying by race. We explored modification of race-stratified associations by neighborhood deprivation, using the Area Deprivation Index (ADI). ResultsBlack participants were more likely to reside within 3 km of chromium-releasing facilities and 5 and 10 km of all observed metal-emitting sites. Living near metal-releasing facilities was not associated with higher toenail metal concentrations overall. Among Black women, higher chromium emissions exposure was associated with higher toenail chromium levels (βTertile3vs.non-exposed = 2.36 μg/g, 95% CI = 0.63, 4.10). An association with lead was observed among Black women residing in the most deprived areas (≥75th ADI percentile: β = 3.08 μg/g, 95% CI = 1.46, 4.71). No associations were observed for White participants. ConclusionsDespite low exposure prevalence, our findings suggest that living near chromium- and lead-releasing facilities, especially at shorter distances, may be associated with higher corresponding toenail metal levels among Black women, particularly those residing in the most disadvantaged areas.

Exposure to iodine, essential and non-essential trace element through seaweed consumption in humans

Seaweed consumption has gained popularity due to its nutritional value and potential health benefits. However, concerns regarding the bioaccumulation of several trace elements highlight the need for comprehensive studies on exposure associated with seaweed consumption. To address this gap in knowledge, we carried out a feeding intervention study of three common edible seaweeds (Nori, Kombu, and Wakame) in 11 volunteers, aiming to elucidate the extent of both beneficial and harmful trace element exposure through seaweed consumption in humans. Concentrations of total arsenic, cobalt, copper, cadmium, iodine, molybdenum, selenium, and zinc were measured in urine samples before and following seaweed consumption. Elements concentrations were also measured in the seaweeds provided for the study. Descriptive analysis for each element were conducted and we used quantile g-computation approach to assess the association between the 8-element mixture and seaweed consumption. Differences in urine element concentrations and seaweed consumption were analyzed using generalized estimating equations (GEE). Urinary concentrations of iodine and total arsenic increased after seaweed consumption. When we analyze the 8-element mixture, the largest weight was observed for iodine after Kombu consumption while for total arsenic was observed after Wakame consumption. Similar results were observed when we compared the mean differences between the elements before and after seaweed consumption through the GEE. Seaweed consumption relates with increased urinary iodine and total arsenic concentrations, particularly after Kombu and Wakame consumption.

Microstructure and Unusual Ferromagnetism of Epitaxial SnO2 Films Heavily Implanted with Co Ions

In this work, we have studied the microstructure and unusual ferromagnetic behavior in epitaxial tin dioxide (SnO2) films implanted with 40 keV Co+ ions to a high fluence of 1.0 × 1017 ions/cm2 at room or elevated substrate temperatures. The aim was to comprehensively understand the interplay between cobalt implant distribution, crystal defects (such as oxygen vacancies), and magnetic properties of Co-implanted SnO2 films, which have potential applications in spintronics. We have utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), differential thermomagnetic analysis (DTMA), and ferromagnetic resonance (FMR) to investigate Co-implanted epitaxial SnO2 films. The comprehensive experimental investigation shows that the Co ion implantation with high cobalt concentration induces significant changes in the microstructure of SnO2 films, leading to the appearance of ferromagnetism with the Curie temperature significantly above the room temperature. We also established a strong influence of implantation temperature and subsequent high-temperature annealing in air or under vacuum on the magnetic properties of Co-implanted SnO2 films. In addition, we report a strong chemical effect of ethanol on the FMR spectra. The obtained results are discussed within the model of two magnetic layers, with different concentrations and valence states of the implanted cobalt, and with a high content of oxygen vacancies.

Температуры окисления инструментальных вольфрамокобальтовых твердых сплавов

Introduction. Products containing WC-Co cemented tungsten carbides are commonly used in various industries. It is often operates at elevated temperatures, at which, as noted in the literature, tungsten carbides are susceptible to severe oxidation in air. However, no sufficiently accurate values of oxidation temperatures and dependence of these temperatures and the oxidation rate of tungsten carbides on the cobalt content with its wide variation have been established. The subject of the study is the oxidation process of WC-Co cemented tungsten carbides. The purpose of the work is to obtain the oxidation temperatures of WC-Co cemented tungsten carbides with different cobalt content by weight in the range of 3–20 %. Methods. The dynamics of oxidation was studied in air. Specimens of the same length were heated to a temperature of 850 °C and cooled at the same rate in the furnace of a push-rod dilatometer Netzsch 402 PC while its expansion was simultaneously recorded. The oxidation rate of the specimens was determined by the difference in its length before heating and after cooling. The values of oxidation temperatures were obtained by mathematical analysis of relationships of the expansion on temperature. Results and discussion. Experimental dependences of expansion of WC-Co cemented tungsten carbides on temperature in the range from 20 to 850 °C, and for WC-8Co – up to 1,150 °C, were obtained. The oxidation rate of WC-Co cemented tungsten carbides increased linearly with increasing concentration of tungsten carbides (decreased with increasing cobalt content). During heating, two characteristic temperatures were identified: the onset of oxidation (631±4 °C) and the transition to active oxidation (804±11 °C). The established temperatures were the same for different ratios of tungsten carbides and cobalt. The results can be used when choosing temperature conditions for products made from WC-Co cemented tungsten carbides.

Assessing cobalt and manganese in foods: A study on determination and health risk using inductively coupled plasma spectrometry

This study aimed to evaluate the concentration and health risk of cobalt (Co) and manganese (Mn) in food using inductively coupled plasma mass spectroscopy (ICP-MS) and ICP optical emission spectroscopy (ICP-OES), respectively. Methods were validated for six food classes based on composition and calorie content. The method limit of quantification (MLOQ) ranged from 0.0766 to 0.2525 μg/kg for Co and 0.0202–0.0832 mg/kg for Mn. Out of 351 food items, Co and Mn were detected above the method limit of detection (MLOD) in 266 and 222 samples, respectively, with highest levels in nuts, seeds, grains, beans, sauces, and seasonings. Pearson correlation analysis showed a significant positive correlation (p < 0.01) between Co and Mn in agricultural (r = 0.390) and processed food (r = 0.543) categories. Exposure to Co and Mn through dietary intake remained within acceptable limits (target hazard quotient (THQ) < 1), suggesting that lifetime consumption is unlikely to elevate potential health risks. In conclusion, this comprehensive study validated methods for Co and Mn analysis and assessed their concentrations and potential health risks across various food categories.

Chemical Analysis and Agricultural Utilizations of Dams Reservoir Sediments

Sediment samples were collected from King Talal Dam (KTD) and subjected to chemical, physical, and mineralogical study to test their suitability as soil replacement. The concentration of Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Nickel (Ni), Arsenic (As), Cobalt (Co), and Zinc (Zn) was obtained by atomic absorption spectrophotometer, and the elements phosphorus (P) and boron (B) were determined by using the spectrophotometric technique. These elements concentration was compared with the average concentration of soil in near by area of Jordan valley, It was found that the concentration of Cu and Zn, P, Fe, Mn, and K is within the standard range for soil fertility, and the concentration of Pb, Ni, As, Co, and Cd is within the standard range of agricultural human health safety regulation’s, the highest concentration on of iron (Fe) and manganese (Mn) in sediment were found to be 1.48% and 15.0 ppm respectively. The lowest average concentration in KTD sediment was identified for cadmium (Cd) and arsenic (As) and was found to be &lt;0.01 and &lt;0.05 ppm respectively. The Laboratory tests carried out indicate that the water of King Talal Dam is free of heavy metals pollutants, and reservoir sediments can be used for soil replacement and amendment. It is highly recommended to keep the percentage of sediments of KTD to soil used in agriculture within the range of 25%-50%.

Investigation of synergistic effects of cobalt doping on physical and dielectric properties of copper oxide nanoparticles

Cobalt-doped copper oxide nanoparticles were synthesized using the composite hydroxide-mediated (CHM) method, and their structural, compositional, dielectric, and impedance properties were investigated. X-ray diffraction analysis revealed a monoclinic crystal structure for all prepared samples with increasing cobalt concentrations leading to a decrease in crystallite size from 44.34 nm to 33.80 nm. The vibrational bands of the different atoms present in these nanoparticles were estimated using Fourier transform infrared spectroscopy. Scanning electron microscopy indicated a predominantly spherical morphology with decreasing particle size upon cobalt doping. Energy-dispersive X-ray spectroscopy verified the elemental composition of the nanoparticles. The dielectric analysis revealed increasing trend in the values of capacitance from 2.19 × 10−12 F to 1.16 × 10−10 F, real part from 3.74 to 1.99 × 102, imaginary part from 5.16 to 6.20 × 103, and tangent loss from 1.37 to 5.60. These parameters got maximum values in low frequency regime as the cobalt replaced copper oxide nanoparticles while these parameters decreased with increasing frequency due to interfacial polarization. Moreover, ac-conductivity revealed increasing values from 2.87 × 10−7 to 3.45 × 10−4 (Ωm)−1 as the cobalt replaced copper oxide nanoparticles in high frequency regime. Both the real and imaginary parts of impedance revealed trends from 3.60 × 107 Ω to 4.59 × 104 Ω and −2.51 × 107 Ω to −1.44 × 103 Ω, respectively, when the cobalt replaced copper oxide nanoparticles. These results revealed that the doping of Co altered the structural and dielectric properties of CuO nanoparticles to making them functional for storage devices.

OXIDATION CHARACTERISTICS OF THERMAL-SPRAYED COBALT-BASED SUPERALLOY COATINGS: A REVIEW

Superalloys go through cyclic oxidation which refers to the progression of reputed exposure of materials to alternating oxidizing and non-oxidizing environments at high temperatures. The oxidation behavior of cobalt-based superalloy coatings depends on several variables, including the environment, surface roughness, manufacturing conditions, &amp; coating composition. Because of their higher temperatures and protective oxide layer, coatings with a greater cobalt concentration are more oxidation-resistant. The behavior of oxidation is influenced by surface roughness, where rough surfaces offer greater surface area to oxidation while smooth surfaces decrease interaction with the environment. The microstructure and porosity of the coating are further impacted by processing variables used in thermal spraying, including temperature, particles velocity, and spray distance. Adding reactive components to the coating composition, such as silicon and aluminum, and applying post-treatments like nitriding or sealing are two ways to increase oxidation resistance. A greater temperature and particle speed can lead to a denser with less porous covering, improving the oxidation process resistance. The two typically used heat spraying techniques are high-velocity oxy-fuel (HVOF) and plasma spraying. To increase the resistance to oxidation of thermal spray cobalt-based superalloy coating, some strategies have been devised, such as inclusion of reactive materials, such as aluminum and silicon, which is the coating composition. These elements may establish an oxide layer protecting the coating’s appearance, preventing further oxidation.

Spatial variations in metals of groundwater in Naini industrial area: assessing probable sources and human health risk

ABSTRACT Groundwater forms the major source of drinking water worldwide; however, its quality has been compromised due to various human activities. The contamination of groundwater with metals have increased the health risk of the consumers. In pursuit of risk assessment and source apportionment studies of groundwater of Naini Industrial Area, Prayagraj, Uttar Pradesh, India; groundwater samples (n = 60) were collected from distinct sampling locations spanning the study area. Inductively coupled plasma-mass spectrometry (ICP-MS) was employed to analyse the concentrations of Aluminium (Al), Arsenic (As), Barium (Ba), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), Selenium (Se), Strontium (Sr), Vanadium (V) and Zinc (Zn). Amongst all the metals analysed, Al and Fe surpassed drinking water standards in more than 50% of the samples. Principal component analysis (PCA) extracted four factors that collectively accounted for 76.3% of the variability in the data. As illustrated by PCA, metals in the groundwater can be attributed to geological origins combined with anthropogenic contributions. Considering the central tendency of the metals, the non-cancer risk as per United States Environmental Protection Agency (USEPA) methodology depicted by Hazard Quotient (HQ) of the metals did not exceed unity and can be inferred that they did not pose risk to the human health individually. However, the combined risk of the metals as depicted by Hazard Index (HI) suggested considerable hazard to the child residents with HI value of 1.27. Across all the sampled sites, the HI values varied from 0.48 to 4.07 for males, 0.41 to 3.51 for females, and 0.76 to 6.51 for children. Considering central tendency, carcinogenic risk associated with As and Cr was determined to be within the tolerable cancer risk value of 1 × 10−4. Nevertheless, the cancer risk for the groundwater surpassed the acceptable limit in few of the locations rendering them unsuitable for drinking without treatment.

ПАЛЕОГЕНОВЫЕ СТОЛБЧАТЫЕ СТРОМАТОЛИТЫ МЕСТОНАХОЖДЕНИЯ «КАМЫШИНСКИЕ УШИ» (НИЖНЕЕ ПОВОЛЖЬЕ)

The article discusses the results of our preliminary studies of Paleocene columnar stromatolites from the “Kamyshinskie Ushi” location, near the northwestern periphery of the town of Kamyshin. The morphology, composition and features of the buildings were studied. They can be attributed to the morphological type of columnar non-branching stromatolites; fan-shaped branching stromatolites are less common; their mineral composition differs little from the host rocks and consists mainly of quartz grains cemented by silicon oxide. Dark layers are much more saturated with ore inclusions. The concentration of chromium, molybdenum, wolfram, vanadium, cobalt and nickel in dark varieties increases noticeably, which confirms their stromatolite origin. The deposition settings of their formation remain controversial.

Index of heavy metal pollution and health risk assessment with respect to artisanal gold mining operations in Ibodi-Ijesa, Southwest Nigeria

BackgroundArtisanal gold mining can help reduce poverty while creating job possibilities for many low-income and unskilled workers. However, it is an activity with several detrimental societal consequences. Miners are exposed to chemical toxins that have long-term health consequences. ObjectivesThis study examined soil degradation, pollution, and environmental hazards from artisanal gold mining in Ibodi-Ijesa, Osun State, Nigeria. The aim is to assess the levels of Cu, Co, Cd, Pb, As, and Ni in the study area as potential indicators of environmental concerns. MethodsSoil samples were systematically collected from 66 distinct locations surrounding the gold mining site, at depths ranging from 0 to 15 cm, within distances of 0 to 500 m, and at intervals of 100 m. These samples underwent standard laboratory procedures for heavy metal analysis using Atomic Absorption Spectroscopy (AAS).Results: The findings showed that copper (Cu), cobalt (Co), lead (Pb), and nickel (Ni) concentrations ranged from 80.17 to 100.11 mg.kg−1, 42.11 to 50.07 mg.kg−1, 30.93 to 54.00 mg.kg−1, and 35.30 to 44.20 mg.kg−1, respectively. Nickel (Ni), cadmium (Cd), and arsenic (As) were all below the detection limit. Although all analysed heavy metal concentrations were lower than the control samples, they outperformed the control values. The contamination index showed no distinct distribution pattern, but all values surpassed those of the control samples. Furthermore, the Health Risk Index was greater than one, indicating possible health hazards for inhabitants. ConclusionThe study indicated that artisanal gold mining operations in Ibodi-Ijesa substantially influenced soil quality, raising heavy metal concentrations and posing health hazards to adjacent populations.

A thermal energy analysis of binary (Go-Co/H2O) and ternary (Go-Co-Zro2/H2O) nanofluids based on characterization and thermal performance

Hybrid or binary nanofluids have superior mechanical and thermal characteristics but the tri-hybrid nanofluids comprise of more embellished thermal properties, better physical strength, and enhanced stability. The present work characterizes the thermal and physical aspects of the hybrid and tri-hybrid nanofluids. The nano-composition of graphene oxide ( Go) and cobalt ( Co) is used in the amalgamation of hybrid nanofluid Go-Co/H2O, whereas the addition of zirconium oxide ( ZrO2) in this mixture gives rise to the ternary Go-Co-ZrO2/H2O hybrid nanofluid. The activation energy and viscous dissipation terms are also amended in the governing equations. The mathematical framework consists of a complex natured dynamical system. However, a numerical algorithm based on finite-difference discretization is developed which can solve the system numerically via the MATLAB software. A comparison with the existing literature is provided in order to validate the numerical procedure. From the outcomes, it is noticed that the temperature of hybrid as well as tri-hybrid nanofuid increases rapidly with change in concentration of zirconium oxide and cobalt. Temperature increases up to 20% by taking 0.1 volume fraction of both zirconium oxide and cobalt. Porous medium and activation energy resist the flow and concentration respectively. A comparative judgment evidently reveals that tri-hybrid Go-Co-ZrO2/H2O nanofluid has a substantial effect on temperature as equated to hybrid or pure nanofluid.