Papers by Keyword: Nickel

Abstract: This study explored the feasibility of removing nickel (Ni) and Pb (II) from water solutions using the adsorption technique by cellulose recovered from office paper waste. Metal removal is required to reduce the direct or indirect exposure of industrial waste to the environment, due to its potential for harm to human health and ecosystems. The release criterion is maintained to keep the efficient wastewater treatment of the metals of concern, which are toxic to both humans and other organisms. The cellulose was first prepared from office paper waste. The removal values can be rationalized as follows: Lead removal efficiencies of were obtained upto %95.0632, while the removals of nickel were obtained as 54.3866%. The adsorption process was effective with the initial metal concentration and the adsorbent dose used. In addition, the study focused on the competition between the adsorption of lead and nickel ions, which inhibited their removal in a mixture. To sum up, in the present study, the prospects of removing heavy metals by low-cost renewable materials are demonstrated, and in general, those concerning the protection of the environment and the minimization of waste.

Abstract: Azolla pinnata extract and iron chloride were combined under optimized conditions using Response Surface Methodology (RSM) to synthesize Azolla pinnata-iron oxide nanoparticles (AP-IONPs). The study investigated the effects of three key parameters mixing ratio of iron chloride to Azolla pinnata extract (v/v), solution pH, and mixing temperature on the removal efficiency of nickel (Ni²⁺) ions from aqueous solutions. A Central Composite Design (CCD) was employed to develop two-factor interaction (2FI) and quadratic models describing the influence of these variables on nanoparticle synthesis and adsorption performance. Analysis of Variance (ANOVA) was used to determine the most significant factors affecting Ni removal. The optimal synthesis conditions were identified as a mixing ratio of 2.5:1, solution pH of 2.5, and a temperature of 70 °C. Under these conditions, the predicted and experimental Ni removal efficiencies were 98.1% and 97.1%, respectively, with a prediction error of just 1.02%. Keywords: Green synthesis; Response surface methodology; Azolla pinnata; Nanoparticles Heavy metals; Nickel; Adsorption.

Abstract: Ni and Ni-containing nanoparticles exhibit promising magnetic properties. In a preliminary experiment, these nanoparticles aggregated after synthesis. Because nanoparticle aggregation may degrade their unique properties, a method to prevent their aggregation is required. In this study, Ni-Pt nanoparticles were synthesized and coated with silica to suppress aggregation. A colloidal solution of Ni-Pt nanoparticles was synthesized in water exposed to air using nickel(II) acetate tetrahydrate (Ni source), hexachloroplatinate(IV) hexahydrate (Pt source), sodium borohydride (reducing agent), and citric acid (stabilizer). Silica-coated Ni-Pt nanoparticles (Ni-Pt/SiO₂) were synthesized by adding a tetraethylorthosilicate (TEOS)/ethanol solution to the colloidal Ni-Pt nanoparticle solution. The morphology of the Ni-Pt nanoparticles varied with reaction time. The Ni-Pt/SiO₂ nanoparticles consisted of Ni-Pt cores and SiO₂ shells, with their morphology dependent on the TEOS concentration. Furthermore, the Ni-Pt/SiO₂ nanoparticles were more dispersed than the uncoated Ni-Pt nanoparticles, suggesting that the silica coating suppressed aggregation.

Abstract: The presence of dunite boulders beneath the limonite zone is a lateritization zonation anomaly because it produces high grades of nickel. This research aims to identify boulders as a source of lateritization and evaluate lateritization zonation concerning major elements. Using XRF laboratory data from systematic zonation sampling the entire data is analyzed by matrix scatter and Pearson Correlation statistics. The results of the research show that the lateritization pattern of boulder dunite has the characteristic that the nickel concentration is slightly influenced by topographic factors and groundwater drainage. However, it is more influenced by rock fractures. As a result, nickel grades are certain to increase suddenly and produce high nickel grades. The interference of silica and magnesium is considered small, thus allowing the presence of rare earth elements.

Abstract: Lanthanum (La) and Nickel (Ni)-codoped Strontium Titanate (SrTiO₃) with the formula of Sr_1-xLa_xTi_1-yNi_yO₃ has been synthesized using the coprecipitation method. This research aimed to determine the effect of nickel and lanthanum co-doping on the photocatalytic activity of SrTiO₃. Here, the Ni concentration (y) was constant at 4%, while La concentrations (x) were varied at 1% and 2%. The synthesized samples were tested via X-ray diffraction (XRD) instrument to determine the crystal structure. It exhibited that the crystallite size reduced along with increased lanthanum concentration. The photocatalytic activity of Sr_1-xLa_xTi_1-yNi_yO₃ was observed under UV and Visible light irradiation against methylene blue (MB) pollutant dyes, and the absorption was measured via a UV-Vis spectrophotometer. It revealed that all samples succeeded in degrading MB solution under the two light sources with exposure times of 1, 2, 3, and 4 hours. Further, it was found that photocatalytic activity with UV lamp irradiation resulted in a better degradation percentage than visible light irradiation. The highest degradation about 60% was achieved by Sr_0.99La_0.01Ti_0.96Ni_0.04O₃ under UV light exposure for 4 hours.

Abstract: Alloy 625 is a Ni-based superalloy with the main alloying elements being Nb, Cr, and Mo. It is known for its excellent corrosion resistance, good weldability, both high heat and creep resistance, and good strength. The current work presents the microstructure of Alloy 625-nTiC metal matrix composites (MMC) fabricated through suction casting. The microstructure and chemical composition of strengthening phases were investigated by light microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that fabricated MMC composites are characterized by a dendritic microstructure with irregular distribution of the strengthening precipitates. Based on chemical composition analysis, the strong enrichment in Nb and Ti was revealed.

Abstract: Undoped and Ni-Eu co-doped ZnO thin films were successfully fabricated via spray pyrolysis at 400°C. The impact of co-doping on the structural, morphological, electrical, and optical properties of the thin films was thoroughly investigated. X-ray diffraction (XRD) analysis confirmed the absence of secondary phases and verified the successful incorporation of dopant ions into the ZnO lattice. Morphological examination revealed enhanced crystallization and a more uniform surface following the incorporation of nickel. Spectral studies in the UV-Vis region were conducted to determine the optical band gap of the synthesized ZnO films, indicating a slight decrease in bandgap values and volume and surface energy losses (VELF and SELF) with increasing Ni doping concentration. Photoluminescence spectra exhibited emission peaks in the UV region around 415 nm and broad visible emissions spanning 450-650 nm for all samples. Electrical characterization using Hall Effect measurements confirmed n-type electrical conductivity in all prepared films, as evidenced by the observed negative Hall coefficients. The co-doped ZnO thin films, particularly those incorporating Ni-Eu, show promise for applications in electronic and optoelectronic devices. Additionally, we investigated the photodegradation of green malachite under a UV lamp. Remarkably, the results demonstrated degradation rates of 93% within 2 hours, showcasing promising potential for practical applications.

Abstract: Welding of dissimilar alloys, specifically that of titanium (Ti) and nickel (Ni), poses numerous challenges due to their significant differences in properties. This review paper aims to provide a comprehensive overview of the challenges associated with the welding of Ti alloys to Ni alloys and explore welding techniques, especially Tungsten Inert Gas (TIG) welding, Metal Inert Gas (MIG) welding, Laser beam welding, Laser-Arc hybrid welding and friction stir welding processes employed in this context. The challenges primarily involve the formation of brittle intermetallic phases, which can compromise joint quality. Additionally, issues such as thermal distortion, oxidation, and corrosion resistance further complicate the welding process. The paper also highlights recent advancements and innovations in dissimilar welding, such as the use of hybrid welding processes and advanced filler materials, to address the challenges and enhance joint performance. The knowledge shared in this review can guide future research and developmental efforts aimed at improving welding techniques, joint quality, and overall performance of Ti to Ni alloys welds.

Abstract: This study proposes a simple method for fabricating metal particles. Metal nanoparticles are synthesized in an aqueous solution. The synthesis method is based on the galvanic replacement of one metal with another, i.e., the deposition of a metal on the surface of another metal using difference between the standard electrode potentials of the metals under ultrasonication. An aqueous colloidal solution of metallic copper (Cu) nanoparticles is prepared using Cu acetate and a metallic zinc (Zn) plate. A similar colloidal solution of metallic Cu nanoparticles is prepared using Cu acetate and a metallic iron plate. No metallic nanoparticles are obtained using metallic aluminum and nickel (Ni) plates because of the formation of passivated layers. An aqueous colloidal solution of metallic Ni nanoparticles is prepared using Ni acetate and a metallic Zn plate; however, Ni_0.7Zn_0.3O is also formed. The results of the study show that the proposed method can be used to produce metallic particles in a simple manner.

Abstract: This research aims to synthesize and characterize Ni(II)-terephthalate-pyrazine complex and to determine the thermal stability and porosity profile of the synthesized compound. The Ni(II)-terephthalate-pyrazine was made by solvothermal reaction using dimethylformamide at 130 and 150 °C and in Ni(II):terephthalic-acid:pyrazine mol ratios of 1:1:2 and 1:1:4. The precipitated products were characterized by infrared spectroscopy, SEM, and powder-XRD in order to confirm the presence of both ligand in the synthesized compound. Meanwhile, the thermal stability and porosity profile of the synthesized compound were determined by DTA-TGA and surface area analysers, respectively. Experimental data shows that green pale powder was obtained from all reactions in considerably good yield, which is different from the dark green crystalline solid of Ni(II)-terephthalate. SEM image reveals that the product has a smooth-wavy surface morphology. Infrared spectra of the synthesized compound show peaks of functional groups of C=O, C–O, C=N, and C–N groups, which confirm the presence of both ligands. Powder XRD analysis suggests that the crystal system of the synthesized compound is different from that of the Ni(II)-terephthalate. Based on these analyses, the targeted Ni(II)-terephthalate-pyrazine is successfully obtained. Moreover, the synthesized compound has lower thermal stability than that of Ni(II)-terephthalate, while the BET calculation suggest that the synthesized compound has pore volume of 0.10-0.14 cm³/g, pore diameter of 8.1-10.65 nm and surface area of 24-30 (m²/g). This porosity profile suggest that the synthesized compound is open for further application, such as adsorption or photocatalysis.