Electrolytic Method Research Articles

Morphology and Distribution of Primary Carbides in Forged Cr-Ni-Mo-V/Nb Steel.

This study aims to investigate in situ the three-dimensional (3D) morphology and distribution of primary carbides (PCs) in electro-slag remelting (ESR) forged 30Cr3Ni3Mo2V steel. A facile non-aqueous electrolytic etching method was applied to prepare 3D PCs on the matrix. The morphology, composition, and element concentrations of PCs were characterized using a combination of optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and electron back-scattered diffusion (EBSD). The precipitation, type, and composition of PCs in the same steel were also simulated using Thermo-Calc software Version 2015a. The results indicate that PC is rich in Nb, which is a potential heterogeneous nucleating agent. Both the size and number of PCs increase from the edge to the center of the ingot. The large-sized PCs present three dominant types of morphology, which vary in different regions, i.e., a bulky type dominates in the edge region, a lamellar type dominates in the middle region, and a stripy type dominates in the core region. The results of EBSD analysis show that the orientation of PCs with different morphologies is different and that more nanosized V-rich type carbides are precipitated on the matrix. The thermodynamic calculations show that MC precipitates from the liquid phase when the solid phase fraction is greater than 0.985 and that the MC-type carbides are rich in Nb, which agrees well with the experimental results.

Study on ductile fracture behavior of hydrogen-charged API pipeline steel

With the increasing focus on reducing carbon emissions, hydrogen has emerged as a promising alternative energy source. However, the safe transportation of hydrogen poses challenges due to its potential impact on the integrity of pipeline materials. This study aims to investigate the effect of hydrogen charging time on the plastic behavior and ductile fracture characteristics of API 5L X42 pipelines, which are commonly used for transporting hydrocarbons. Tensile tests were conducted on various types of hydrogen-charged specimens at room temperature to assess different fracture modes. Hydrogen was introduced into the specimens using a cathodic electrolytic method, and 24-h charging time durations were considered. Finite element analyses were performed on standard dog-bone and notched tension specimens to evaluate the plastic behavior, employing the Swift hardening law to model the flow stress. Numerical analyses were conducted to determine the loading path leading to fracture initiation. A damage framework based on the Hosford–Coulomb model was utilized to predict ductile fracture under non-proportional loading conditions. The findings of this study provide insights into the fracture behavior of pipelines under hydrogen exposure, aiding in the design and assessment of safe and reliable hydrogen transport systems.

Optimasi Pemisahan Perak dari Limbah Fixer melalui Variasi Tegangan

Fixer solution is a chemical substance in the form of a concentrated liquid that is used to wash radiographic films. The Fixer Solution functions to dissolve the silver halide layer on unexposed radiographic films. This research aims to design a waste fixer solution processing device using the electrolysis method and to regulate the voltage to the optimal point to produce a large electrolysis rate. Design an electrolysis device using stainless steel electrodes with a trapezoidal cathode with parallel sides of the cathode with lengths of 170 mm, 145 mm and a cathode height of 155 mm. The anode is rectangular with a length of 30 mm and a height of 169 mm. The method for making tools goes through several stages, namely making tool designs, testing tools, and testing waste fixer solution. The fixer waste used comes from Betesdha Wonosari Hospital. In this research, each test used 5 liters of fixer waste at each voltage which was regulated for 3 hours. The higher the mass voltage produced, the higher the electrolysis rate will be. However, the higher the voltage, the faster the sulfidation process will be. In the design of this fixer waste management tool, it can work optimally at a voltage of 4 V with a speed of 4.87 g/hour.

Analysis of the Particle Size and Morphology of Tin Powder Synthesized by the Electrolytic Method.

This article discusses the effect of electrolysis parameters on the particle size and morphology of the tin powder synthesized by the electrolytic method. The electrolytic method is simple and can eliminate the risk of lead and arsenic gas emissions owing to the low temperature of the process. The effects of tin concentration in a sulfate-based electrolyte, a mass ratio of thiourea/gelatin as additives, current density, and electrolysis time on the particle size and morphology of the synthesized tin powder were examined. Pure tin and titanium plates were used as the anode and the cathode, respectively. After the electrolysis experiments were completed, the synthesized tin powders were analyzed by a particle size analyzer, a scanning electron microscope, and X-ray diffraction. The optimum condition of the experiment that resulted in the highest D90 was achieved at an initial concentration of SnSO4 = 3 g/L, a mass ratio of thiourea/gelatin = 1/4, a current density of 1 A/dm2, and a 10 min electrolysis time. Under this condition, 90% of the tin powder size obtained was smaller than 2.279 μm, showing a rounded morphology with a length-to-width ratio of 1.15. The current efficiency increased with increasing tin concentration, decreasing current density, and a shorter electrolysis time.

Low-level tritium measurements in freshwater and seawater samples

The aim of this study was to test two potential tritium determination methods (with and without electrolysis enrichment) suitable for low-level measurements. Both methodologies were applied to water samples from the Baltic Sea and ten Polish rivers providing new data on tritium activity concentration. Optimization steps carried out to the standard method lowered minimum detectable activity concentration (MDC) from 3.1 to 1.8 Bq L–1 (at 95% confidence level) enabling to apply it to environmental water samples. However, electrolytic enrichment method of MDC of 0.20 Bq L–1 provided more accurate results for tritium activity concentration in surface waters.

Methodology for choosing a hydrogen source based on a point system

The article examines the usage of hydrogen in gas transmission pipes as one of the measures to achieve the criteria of sustainable development and reduction of carbon emissions. Regarding choosing an appropriate kind, hydrogen sources have been analyzed. Due to the multifactorial nature of the task, such as raw material, price, efficiency, popularity, and the availability of many studies, a point system was developed to evaluate the alternatives with significant criteria. On its basis, it was established that the cheapest and gentlest natural method is the electrolysis of water. For this purpose, electrolysis methods have been evaluated, and efficiency depends on the energy source. Given the dependence of the price of energy on the country's energy mix, a point system is proposed based on the parameters: hydrogen's levelized cost LCOH and levelized cost of electricity (LCOE). The newest criterion is the citation rating which gives popularity and an opportunity for new research.

Characterization of Synthetic Brushite Material Precipitated at Room Temperature Developed for Kidney Stone Treatment

Studies on Brushite, which was initially considered as a mineral found in caves, started when it was seen in kidney stones, and finally its applications continued. These studies were focused on synthetically obtaining Brushite. The biggest difficulty in obtaining Brushite synthetically is the execution of complex chemical and sequential processes at high temperatures. Obtaining a stable crystal structure at high temperatures brings another challenge. In this study, for the first time in the literature, the synthesis of Brushite at room temperature by using simple electrolyte, characterization of the precipitates with different methods, and the details of their electrochemical and mechanical behaviour were shared with the readers. Brushite was precipitated on the X2CrNiMo17‐12‐2 materials by using electrolytic method. In the characterization of Brushite deposits, energy dispersive X‐ray microanalysis (EDS), X‐ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and optical microscope with image analyser were used. Dynamic ultramicro hardness, scratch, and friction‐wear testing equipment were used in mechanical analyses. It has been determined that the electrochemical decomposition of the Brushite material, which was successfully synthesized at room temperature, is quite difficult, and a mechanical load of 10 mN has been defined to be the critical value.

CO2 conversion to CO via plasma and electrolysis: a techno-economic and energy cost analysis.

Electrification and carbon capture technologies are essential for achieving net-zero emissions in the chemical sector. A crucial strategy involves converting captured CO2 into CO, a valuable chemical feedstock. This study evaluates the feasibility of two innovative methods: plasma activation and electrolysis, using clean electricity and captured CO2. Specifically, it compares a gliding arc plasma reactor with an embedded novel carbon bed system to a modern zero-gap type low-temperature electrolyser. The plasma method stood out with an energy cost of 19.5 GJ per tonne CO, marking a 43% reduction compared to electrolysis and conventional methods. CO production costs for plasma- and electrolysis-based plants were $671 and $962 per tonne, respectively. However, due to high uncertainty regarding electrolyser costs, the CO production costs in electrolysis-based plants may actually range from $570 to $1392 per tonne. The carbon bed system in the plasma method was a key factor in facilitating additional CO generation from O2 and enhancing CO2 conversion, contributing to its cost-effectiveness. Challenges for electrolysis included high costs of equipment and low current densities. Addressing these limitations could significantly decrease production costs, but challenges arise from the mutual relationship between intrinsic parameters, such as CO2 conversion, CO2 input flow, or energy cost. In a future scenario with affordable feedstocks and equipment, costs could drop below $500 per tonne for both methods. While this may be more challenging for electrolysis due to complexity and expensive catalysts, plasma-based CO production appears more viable and competitive.

Rapid plasma electrolytic oxidation preparation of sub-3 nm half-embedded intermetallic nanocatalysts for efficient selective hydrogenation

Monodisperse sub-3 nm ordered intermetallic nanoparticles half-embedded in a porous MgO support layer on a Mg plate were prepared for the first time.

The Effect of Air Injection Flowrate on Nitrate Synthesis with The Addition of Fe2+ Ions Using Plasma Electrolysis

This study aims to determine the effect of air flow rate on nitrate synthesis with the addition of Fe2+ ions using the plasma electrolysis method. Nitrate synthesis usually uses conventional technology that causes air emissions. So that plasma electrolysis technology is needed that does not cause emissions and is environmentally friendly. The methods used in this study include designing a plasma electrolysis reactor using 0.02 M K2SO4 electrolyte, testing the plasma electrolysis reactor to determine the formation of a glow discharge zone as an indicator of the nitrate synthesis process, testing nitrate production using a UV VIS spectrophotometer and •OH radicals using HPLC. The air reaction rate at variations of 0.2 Lmen-1, 0.4 Lmen-1, 0.6 Lmen-1, 0.8 Lmen-1 and 1 Lmen-1 was injected into the reactor. The concentration of Fe2+ ions at 10 ppm, 20 ppm, 30 ppm, 40 ppm and 50 ppm was analyzed to determine the effectiveness of the ion. The results obtained were that the highest nitrate at 400 Watt power was 2976 ppm, at 500 Watt power was 3063 ppm, and at 600 Watt power was 3373 ppm. the highest nitrate production was achieved at a concentration of 30 ppm with a result of 2785 ppm, followed by a concentration of 40 ppm with a result of 2645 ppm, a concentration of 20 ppm with a result of 2512 ppm, a concentration of 10 ppm with a result of 2478 ppm, and a concentration of 50 ppm with a result of 2364 ppm..

An overview of green hydrogen production system through low temperature water electrolysis using solar energy

Climate change and the increasing demand for energy become major issues in public discussions today. The Paris Agreement is one of the results of such public discussions that focuses on achieving the 2050 Net Zero Emission target. Many energy agencies have created scenarios to achieve this target. In this regard, green hydrogen is expected to have a significant role in energy transition plan. For this reason, in recent years, research related to green hydrogen production using the water electrolysis method continues to develop. The paper aimed primarily to conduct an overview of alternative technologies that can be used in producing green hydrogen with the solar energy based low temperature water electrolysis method. Secondarily, it would present information about several solar energy-based electrolysis project plans and a summary of challenges and opportunities in the development of solar energy based low temperature water electrolyzers in the future. Furthermore, to achieve commercially viable green hydrogen production, it is important to find new ideas, potential solutions, and constructive recommendations as soon as possible for further development research. This paper expectedly would be able to help initiate the development of green hydrogen production research through water electrolysis technology that is efficient, cost effective economically, and environmentally friendly.

Numerical study on inclusion collision, coalescence and removal in an extra-thick slab continuous casting mold with M-EMS

Surface flaw detection is one of the main problems of extra-thick slab. In practice, it is considered that the application of mold electromagnetic stirring (M-EMS) is an effective means to reduce the inclusions located at the subsurface of thick slab. The present study conducted numerical studies on the inclusion transports in an extra-thick slab continuous casting mold with the effects of M-EMS. The influences of M-EMS on the inclusion collision, coalescence and removal were revealed. The predicted results indicate that the majority of inclusions entering the mold are smaller than 20 µm. The application of M-EMS promotes the collision, aggregation, and flotation of these inclusions. When the inclusions entering the mold are larger than 30 µm, the flotation removal of inclusions significantly increases, and the collision and aggregation among inclusions decreases accordingly. Furthermore, the predicted results show that inclusions larger than 200 µm in size are unlikely to follow the downward flow into the lower region of the mold, with the primary removal location concentrated near the nozzle. Large-size inclusions have been quantitatively extracted from samples with and without M-EMS using galvanostatic electrolysis method. The results indicate that the inclusions of various sizes in the slab surface layer are reduced when M-EMS is employed. Notably, inclusions sized 50–150 µm show the most significant reduction, with their mass density decreasing from 38.17 mg/10 kg to 15.11 mg/10 kg. This demonstrates a substantial reduction in large-size inclusions on the slab surface layer following the introduction of M-EMS in the mold.

Gem-Difluorination of carbon-carbon triple bonds using Brønsted acid/Bu4NBF4 or electrogenerated acid.

gem-Difluorination of carbon-carbon triple bonds was conducted using Brønsted acids, such as Tf2NH and TfOH, combined with Bu4NBF4 as the fluorine source. The electrochemical oxidation of a Bu4NBF4/CH2Cl2 solution containing alkyne substrates could also give the corresponding gem-difluorinated compounds (in-cell method). The ex-cell electrolysis method was also applicable for gem-difluorination of alkynes.

Electrolytic preparation of two-dimensional layered sulphur nanomaterials and their application in lithium-sulphur batteries

Currently, two-dimensional (2D) layered materials have gained much attention for their outstanding properties. Among these materials, layered sulphur, which is an emerging 2D material, has shown great potential for various applications due to its unique chemical and physical properties. In this study, we present a new electrolytic method for synthesizing layered sulphur using thiourea as the sulphur source and poly-3,4-ethylenedioxy thiophene/polystyrene sulfonate (PEDOT: PSS) as the stabilizer. This method is simple, fast, and has a high yield. Furthermore, a composite material was prepared containing carbon nanotubes (CNTs) and layered sulphur, which was used a cathode material in lithium-sulphur batteries. The prepared cathode exhibited a discharge specific capacity of 450 mAhg−1 and a reversible capacity of 46.6% after 40 cycles of reciprocation at 0.1 C cycling current. Electrode design based on layered sulphur composites provides a new idea for the structural design of lithium-sulphur battery cathodes.

Cleaner extraction of white phosphorus from phosphate rock through molten salt electrolysis

White phosphorus (P4) is an essential raw material for the production of phosphorus chemicals. The conventional carbothermal reduction process used to extract P4 from phosphate rock is known as energy intensive and environmentally polluting, posing obstacles to meeting the urgent global demands for clean production and carbon neutrality. Moreover, the low product purity restricts its application in high-value industries. This paper presents an original approach that is both simple and coke-free for extracting high-purity P4. The method involves electrolyzing dissolved phosphate rock in molten CaCl2 at a mild temperature. We undertake an in-depth investigation into the dissolution behavior of phosphate rock in molten CaCl2 and the electrolysis behavior of the melt. The experiments demonstrate the rapid dissolution of phosphate in the rock when exposed to molten CaCl2, reaching saturation within a short time (e.g., within 10 min at 850 °C). The dissolution of phosphate shows a preference over silicates present in the phosphate rock. The electrochemical reduction of PO43− in molten CaCl2 is electrochemically reversible, as observed at potential scan rates not exceeding 0.20 V s−1. The obtained P4 product through electrolysis is of higher purity compared to the industrial-grade commercial product produced via carbothermal reduction. The implementation of pre-electrolysis can further improve the purity of the product and the current efficiency of the electrolysis process. The theoretical electricity and carbon consumption in the electrolysis method are estimated to be 9.12 kWh and 0.53 kg, respectively, for every 1 kg of P4 produced. These values are lower than the conventional carbothermal reduction process. This cutting-edge electrolysis method represents a paradigm shift towards a more sustainable development of the phosphorus chemical industry, thereby showcasing its potential for revolutionizing the field.

Перспективы Крайнего Северо-Востока России на производство "зеленого" водорода с использованием климатических источников возобновляемой энергии

For the first time, Russia's Far North-East prospects for hydrogen production by the method of water electrolysis, using climatic energy sources and ultra-fresh mountain-river water, are comprehensively assessed. Taking into account the identified regional features, it is calculated that, with the current technical level of development, the amount of hydrogen produced in the region will be controlled just by the amount of used ultra-fresh mountain-river water. Thus, using no more than 10 percent of the general runoff (18 billion m3 water), it is possible to annually obtain 2x109 tons of "green" hydrogen through the operation of wind and solar power plants. To accommodate the latter, it is ecologically feasible to use the areas in mountain tundras and forest-tundras on flattened and flat watersheds.

Critical Review of Hydrogen Production via Seawater Electrolysis and Desalination: Evaluating Current Practices

Abstract The pursuit of sustainable and clean energy solutions has led to increased interest in hydrogen as an efficient energy carrier. This paper presents a comprehensive analysis of state-of-the-art technologies for hydrogen production through seawater electrolysis and desalination, addressing the critical need for clean energy generation and sustainable water supply. It emphasizes the importance of hydrogen as a versatile and environmentally friendly energy source, as well as the significance of seawater desalination. The analysis includes a comparison of three electrolysis technologies: solid oxide electrolysis (SOE), alkaline electrolyzers (AE), and proton exchange membrane (PEM) electrolysis. Factors such as energy requirements, capital and maintenance costs, and offshore suitability are considered, facilitating an informed evaluation of the most suitable electrolysis method for seawater hydrogen production. Additionally, three desalination technologies are evaluated: reverse osmosis (RO), thermal desalination, and membrane desalination. The assessment takes into account investment and operation costs, energy demand, and environmental impact, providing insights into the feasibility and sustainability of integrating hydrogen production with seawater desalination. This condensed review provides a holistic perspective on the techno-economic viability, energy efficiency, and environmental sustainability of various technologies, enabling informed decision-making towards a more sustainable and resilient energy-water nexus. Overall, this study contributes to the growing body of knowledge on hydrogen production and seawater desalination, offering insights that can inform strategic planning, policy development, and technological advancements in achieving a greener and more sustainable future.

Anodic Synthesis of Peptides in Biphasic Electrolytic Solutions

Peptide synthesis requires a large amount of condensing reagents, and once the condensation is complete, all of the reagents become waste. Based on the recognition of these issues, we decided to investigate the possibility of linking the condensing agent function to electrode electron transfer. Using this reaction system, all the elongation reaction steps were carried out by the electrolytic method. The electrolytic peptide synthesis method has been confirmed to efficiently proceed with the condensation of all amino acids, and the products and by-products can be easily separated. It is expected to be applied as a material production method that significantly reduces the use of energy and materials.

The Importance of Current Density in Electrolytic Phosphate Coatings

Phosphate coatings have been a popular choice for the treatment of steels and other ferrous alloys for a number of decades. In the most common embodiment of the process, phosphate coatings are produced by a conversion reaction between the steel surface and an acidic conversion bath. The resulting coatings are composed of phosphate crystals which act as a physical barrier between the environment and the underlying metal, protecting it from corrosion and wear [1]. Despite being a cheap and well-affirmed technology, conversion phosphating has recently been scrutinized due to its high environmental impact. In fact, one of the main byproducts of the process is a sludge containing phosphates and heavy metals from the deposition bath.A potential solution to the environmental burden carried by the conversion process is represented by the electrolytic deposition method. In this case, the increase in interfacial pH necessary for phosphate precipitation is obtained by applying a cathodic polarization to the samples to coat in an electrolytic setup. As a consequence of the potential shift, substrate dissolution is prevented and so is sludge formation [2].In this work, we demonstrate how the choice of current density influences the resulting properties of zinc phosphate coatings obtained by electrolytic deposition on low carbon steel substrates. Aside from the deposition rate, the applied current density is found to be a determinant factor in the morphology of the coatings as it can be seen in Figure 1. In turn, this affects other properties such as wear and corrosion resistance.[1] B. Díaz, L. Freire, M. Mojío, and X. R. Nóvoa, “Optimization of conversion coatings based on zinc phosphate on high strength steels, with enhanced barrier properties,” J. Electroanal. Chem., vol. 737, pp. 174–183, Jan. 2015.[2] S. Jegannathan, T. S. N. Sankara Narayanan, K. Ravichandran, and S. Rajeswari, “Performance of zinc phosphate coatings obtained by cathodic electrochemical treatment in accelerated corrosion tests,” Electrochim. Acta, vol. 51, no. 2, pp. 247–256, Oct. 2005. Figure 1

Fixation of air nitrogen to ammonia and nitrate using cathodic plasma and anodic plasma in the air plasma electrolysis method

AbstractThe fixation of nitrogen (N2) from the air into ammonia (NH3) and nitrate (NO3−) is usually conducted using the Haber–Bosch process, which requires the raw material of hydrocarbons for hydrogen (H2), which has a large amount of energy but produces high CO2 emissions. An environmentally friendly and energy‐saving alternative is the air plasma electrolysis method, which can be used to synthesize NH3 and NO3− under ambient conditions. In this study, this method was used to inject air into the plasma zone in a K2SO4 electrolyte solution to produce N2 fixation compounds. The results showed that the use of cathodic plasma promoted the formation of NH3 but suppressed NO3− production. The optimal air injection rate was achieved at 0.6 L.min−1 and an electrical power of 452 W, with a total fixed N2 of 51.66 mmol. The highest formation of NO3− in cathodic plasma was obtained in 35 min, with a value of 29.92 mmol, and 2.57 mmol NH3 was achieved at 60 min. The high concentration of H2 gas, which is a by‐product of this process, can contribute to increasing the use of Haber–Bosch green technology in the production of NH3.