Titanium Electrodes Research Articles

Performance evaluation and life cycle assessment of electrocoagulation process for manganese removal from wastewater using titanium electrodes

Excess manganese (Mn) concentrations can pose environmental and health risks. Currently, research on Mn removal by electrocoagulation (EC) using transition metal electrodes and the determination of its potential environmental impacts is limited. This study aims to assess the electrocoagulation process's performance with a titanium electrode as a sacrificial anode while also performing a life cycle assessment (LCA) of the process. The initial pH, current density (CD), electrode spacings, electrolyte types, concentrations, and electrode arrangement were all examined. For synthetic wastewater, most of the experiments used a concentration of Mn of 2 mg/L and sodium chloride as a supporting electrolyte at a concentration of 1 g/L. LCA software (OpenLCA 1.11) was used to assess the potential environmental impacts. Optimal operating conditions within the experimental range were as follows: initial pH = 7, CD = 10 mA/cm2, gap distance = 2 cm, and 1 g/L NaCl. Under these conditions, the maximum Mn removal efficiency was 96.5% after 60 min. There was an improvement of 2% rise after 60 min when the temperature increased from 20 °C to 40 °C. For real wastewater, the highest removal efficiencies for Mn and chemical oxygen demand after 60 min were 91.3% and 92%, respectively. The pseudo second order model provides the highest coefficient of determination for expressing the experimental data. Global warming, human non-carcinogenic toxicity, and terrestrial ecotoxicity were the most important categories of impact examined in this work according to the LCA (0.00064 kg CO2 eq, 0.00018 kg 1,4-DCB, and 0.00028 kg 1,4-DCB, respectively). To effectively remove Mn using EC with Ti electrodes, it appears that a period of electrolysis of 10 min would be sufficient under most of the conditions investigated in this study. The reduction in the electrolysis time will lead to a reduction in the operating costs of the system.

A DSSC Electrolyte Preparation Method Considering Light Path and Light Absorption.

The electrolyte is one of the key components of dye-sensitized solar cells' (DSSC) structure. In this paper, the electrolyte formulation of a new DSSC with external photoanode structure was studied. Based on the idea that the electrolyte should match the light absorption and light path, iodine series electrolytes with different concentrations were configured and used in the experiment. The results showed that the external photoanode structure solar cells assembled with titanium electrode had the best photoelectric conversion ability when the concentration of I2 was 0.048 M. It achieved the open circuit voltage of 0.71 V, the short circuit current of 8.87 mA, and the filling factor of 57%.

Dependence of Skin-Electrode Contact Impedance on Material and Skin Hydration.

Dry electrodes offer an accessible continuous acquisition of biopotential signals as part of current in-home monitoring systems but often face challenges of high-contact impedance that results in poor signal quality. The performance of dry electrodes could be affected by electrode material and skin hydration. Herein, we investigate these dependencies using a circuit skin-electrode interface model, varying material and hydration in controlled benchtop experiments on a biomimetic skin phantom simulating dry and hydrated skin. Results of the model demonstrate the contribution of the individual components in the circuit to total impedance and assist in understanding the role of electrode material in the mechanistic principle of dry electrodes. Validation was performed by conducting in vivo skin-electrode contact impedance measurements across ten normative human subjects. Further, the impact of the electrode on biopotential signal quality was evaluated by demonstrating an ability to capture clinically relevant electrocardiogram signals by using dry electrodes integrated into a toilet seat cardiovascular monitoring system. Titanium electrodes resulted in better signal quality than stainless steel electrodes. Results suggest that relative permittivity of native oxide of electrode material come into contact with the skin contributes to the interface impedance, and can lead to enhancement in the capacitive coupling of biopotential signals, especially in dry skin individuals.

Fabrication of Ag/TiO2 nanotube array as active electrocatalyst for the hydrogen evolution reaction

Silver nanoparticles (Ag NPs) were fabricated onto titanium substrates with and without titania nanotubes arrays (TiO2 NTs) using electrochemical and chemical techniques, respectively, to create nanostructured electrocatalysts for the hydrogen evolution reaction (HER). The active surface area of the catalyst is determined by the Ag NPs' structure and the presence of TiO2 nanotubes on the titanium substrate. The electrocatalytic activity was improved by chemically synthesizing Ag NPs onto a titanium electrode that had been precoated with TiO2 nanotubes.

Membrane-free electrodeionization using graphene composite electrode to purify copper-containing wastewater.

Membrane-free electrodeionization (MFEDI) technology involves in situ electric regeneration of ion exchange resin, and is used to efficiently purify copper-containing wastewater, so that both the wastewater and copper may be reused. The electrode is the core functional component of a MFEDI system. Electrode-selection greatly influences the electric regeneration efficiency, water recovery and energy consumption of MFEDI processes. In this study, a graphene composite electrode was developed to improve MFEDI-system performance. A graphene composite electrode and conventional platinum-plated titanium electrode were both characterized by scanning electron microscopy (SEM) and electrochemical testing. Furthermore, the treatment and electrical regeneration properties of MFEDI systems with these two electrodes were investigated. The specific surface area of the electrode increased after graphene loading, while the oxygen evolution potential decreased. Wastewater treatment experiments demonstrated that MFEDI systems with graphene composite electrodes effectively removed copper from wastewater. The study also highlighted that the electroregeneration efficiency of the MFEDI system was improved by loading with graphene; the average copper concentration in the regeneration solution increased by 1.4 times to 50.4 mg/L, while the energy consumption decreased from 1.55 to 1.48 kWh/m3, and the water recovery rate increased from 85 to 90%.

Application of hybrid electrocoagulation and electrooxidation process for treatment of wastewater from the cotton textile industry.

The hybrid electrocoagulation-electrooxidation (EC-EO) process was evaluated for its capability to remove color, total organic carbon (TOC), and chemical oxygen demand (COD). Aluminum (Al/Al) and iridium dioxide-coated onto titanium (IrO2/Ti) electrodes were selected as anode/cathode for EC and EC-EO experiments, respectively. The box-Behnken statistical experimental design was used to optimize different operating conditions of the processes. The selected EC operating parameters are the concentrated dye concentration, applied current density, electrolysis time, and pH. The three chosen operating conditions for hybrid EC- EO processes are applied current density, pH, and electrolysis time. The results were evaluated based on the interaction effects of operating parameters of the treatment methods on the percentage of COD, TOC, and color removal. The EC process achieved 89% color and 76% COD removal rate at the optimum operating conditions. Likewise, the hybrid EC-EO process obtained 97% COD and color removal efficiency. FT-IR and 1H and 13C NMR spectroscopy combined approach was employed to analyze the dye degradation extent. Both analysis results confirm the complete degradation of the organic contaminants into carbon dioxide and water. Thus, this study discloses that the treatment method using mesh IrO2/Ti electrodes is a promising technology that could reach the discharge limit for industrial effluents. In addition, the optimum operating conditions are tested for real industrial wastewater effluents and show excellent performance in removing pollutants. Furthermore, the treatment method's mineralization study and economic analysis were performed and compared to other studies.

ENVIRONMENTALLY SAFE TECHNOLOGY FOR SYNTHESIZING TITANIUM TRICHLORIDE FOR THE NEEDS OF VARIOUS INDUSTRIES

The authors have assessed the possibility of electrochemical synthesis of a wide range of reagents based on titanium trichloride as part of the work. Despite the growing demand for titanium trichloride and its derivatives, the production technology of this reagent has not been improved for a long period. Traditional technologies feature high environmental and industrial hazards, and the process itself has high energy consumption and a complex hardware scheme. As part of preliminary work, the possibility of obtaining titanium trichloride from aqueous solutions of titanium tetrachloride is established, while the proposed technology is distinguished by reduced energy consumption and safety. At the first stage of experiments in the anodic dissolution of aluminum, binary solutions of titanium trichloride and aluminum chloride are obtained. The degree of conversion TiCl4 → -TiCl3 is 65%–35% for a current density of 10–30 A/dm2, respectively. In the process of reducing an aqueous solution of titanium tetrachloride with iron electrodes, the yield of titanium trichloride is approximately 76%–66% for a current density of 10–30 A/dm2, respectively. The resulting solution is heavily contaminated with iron (II) compounds. The results of the experiments show the high efficiency of this solution in the processes of purification of wastewater from galvanic production from chromium (VI) compounds. For the production of high-purity titanium trichloride, titanium electrodes are used, while the yield of titanium trichloride is 59%–3% for a current density of 10–30 A/dm2, respectively. Depending on the production technology and electrode material, solutions are obtained that can be used to produce high-purity titanium dioxide for the production of dye-sensitized solar cells, reagents for water purification, and a Ziegler-Natta catalyst and a reagent for organic synthesis.

Electrochemical oxidation process on palm oil mill effluent waste activated sludge: optimization by response surface methodology.

Biological-based treatment as the conventional treatment for palm oil mill effluent (POME) in open-ponding system face a well known rate-limiting step which is hydrolysis. In this study, electrochemical oxidation (EO) by a ruthenium oxide-coated titanium (Ti/RuO2) electrode was introduced as a pre-treatment for POME waste activated sludge (WAS). Surface morphology and elemental analysis were investigated using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Response surface methodology type central composite design was used in this study to understand the relationship between the independent and dependent variables. Analysis of variance (ANOVA) was used to validate the model of the studied variables. The correlation coefficients (R2) indicated a close agreement between the experimental results and the predicted values, with high R2 values of 0.9044-0.9773. Multiple response optimization suggested that the range of current density (17-27 mA/cm2) and electrolysis time (55-75 min) at a fixed concentration of sodium chloride (10 g/L), resulted in mixed liquor volatile suspended solids (MLVSS) removal >20%, capillary suction timer (CST) reduction >43%, extracellular polymeric substances (EPS) increment <19% and soluble chemical oxygen demand (sCOD) increment >25%. EO appears to be an efficient pre-treatment as well as practical way to improve the POME WAS disintegration and dewaterability.

Surfactants in electrokinetic remediation of sediments to enhance the removal of metals

PurposeThe study focuses on the use of surfactants as enhancing solutions in electrokinetic remediation trials on sediments, with the hypothesis that they will allow heavy metals to desorb from organic matter, and thus favour their removal to the solution.Materials and methodsA total of 15 remediation trials were conducted. As enhancing solutions, four different non-ionic commercial surfactants were used, either alone or in combination with citric acid (CA) or ethylenediaminetetraacetic acid (EDTA) in both compartments. A comparison with distilled water was also performed. 30–40 VDC was applied between activated titanium electrodes. The pH, electroosmotic flow (EOF), mineralogy of the samples (before and after the electrokinetic tests), and the percentage of removal of Cr, Ni, Cu, Zn, As, Cd, Pb, and Hg were determined.Results and discussionEvery test showed an increase in current intensity during the first hours, and in certain cases, additional intensity peaks were found during the trial, which were mostly attributed to the establishment of EOF episodes. Depending on the case, EOF was transferred to the anolyte or the catholyte. Reversal of EOF occurred in one case, but was not detected in the others. Cr was primarily removed when CA was used. In the catholite, Ni, Cu, Zn, and Pb were extracted preferentially with EDTA. Surfactant B was more effective at removing Zn and As. Only a few treatments removed Cd with CA and surfactant C extracting the most. Hg was detected in the electrolytes of some experiments, being extracted with surfactant A in the catholyte in all cases, and with surfactant B and surfactant C with EDTA. Cr, Ni, Cu, Zn, Cd, and Pb were preferentially collected in the anolyte. Cu and Zn were found in trace levels in the catholyte.ConclusionsSurfactants have been shown to help with metal solubilisation to different degrees depending on the metal. Each metal has a unique optimal species combination in the enhancing electrolyte. The direction of the EOF is determined by the chemical conditions of the system as a whole, not by the type of surfactant. Surfactants in combination with CA and EDTA improve desorption in general, which has been attributed to an increase in charge density passed during the tests rather than a symbiotic enhancement between both types of enhancing solutions.

Galvanic Deposition of Ir-Pt-Particle As Bifunctional Catalyst for Unitized Regenerative PEM Fuel Cell

On the road to climate neutrality, hydrogen is becoming increasingly important as an energy carrier. This increase in importance is clearly illustrated, for example, by the hydrogen strategy adopted by the European Union (EU) in summer 2020, which aims to transform the EU's energy system, which is predominantly based on fossil fuels, and its sectoral value chains into a climate-neutral, integrated energy system. Regeneratively produced hydrogen is the energy carrier of the future. It is suitable for energy supply and enables the desired sector integration between the industrial, transport, energy and building sectors. [1] In order to make hydrogen fuel efficiently usable as an energy carrier of the future, electrochemical technologies are needed for the production of regenerative hydrogen as well as the reconversion of hydrogen into electricity. One possibility is polymer electrolyte membrane (PEM) technology. With PEM electrolyser cells (PEMEL), hydrogen can be produced by splitting water with electricity. For the reconversion of the hydrogen into electricity, the PEM fuel cell (PEMFC) can be used. This recombines hydrogen with oxygen to form water (with the release of electricity and heat). For the conversion chain two separate systems are required. A combination of both technologies can be realized by means of the unitized regenerative PEM fuel cell UR-PEMFC with internal reaction reversal. [2] This approach places special demands on the design of the oxygen electrode and the catalysts used there, since the reactions at this electrode represent the limiting factor for the performance of the cell. While platinum is the most suitable catalyst at the hydrogen electrode in both electrolyzer and fuel cell operation, a distinction must be made between the operating modes at the oxygen electrode. In fuel cell mode, the oxygen reduction reaction ORR takes place at the oxygen electrode. Platinum is a suitable catalyst for this. When switching to electrolyzer mode, the oxygen formation reaction OER takes place, with iridium proving to be the best catalyst, especially with regard to long-term stability. Accordingly for the oxygen electrode of a UR-PEMFC a bifunctional catalytic layer must be used. The composite of appropriately structured electrode material (titanium) and bifunctional catalyst layer is called a bifunctional oxygen electrode BOE. [3]In this work, the electrodeposition of iridium-platinum alloy particles as a catalyst for a BOE was investigated. The deposition was first performed galvanostatically from electrolytes containing iridium and platinum ions in different concentration ratios. First, the influence of the electrolyte composition and the deposition parameters, such as current density and temperature, on the alloy composition was investigated. Electrolytes based on hexabromoiridate and diammineplatinum(II) nitrite were used to deposit alloys with iridium mass fractions between 40% and 60%, which corresponds to the typical composition from other publications, in which the catalyst particles are mixed in the slurry [3], [5], [6]. Current yields between 40% and 50% were determined for the production of closed layers. The alloy composition was characterized using X-ray fluorescence analysis and enegiedispersive X-ray spectroscopy. Examination of the surface morphology by scanning electron microscopy showed that no isolated particles could be produced on the titanium electrode by galvanostatic deposition. Rather, exposed areas are loaded with too much catalyst, while other surface sections could not be covered with catalyst material. However, a homogeneous distribution of the catalyst particles is crucial for increasing the cell conductivity. For this reason, the electrolyte composition found was used for pulse current experiments. The pulse times were varied between 10 and 50ms. The pulse pauses were chosen so that one pulse cycle lasts 100ms. The best results were obtained with a pulse time of 25ms and a puls current density of 40mA/cm². Particles with an iridium mass fraction of 45% were deposited homogeneously on the oxygen electrode. Assuming a Faraday efficiency of 40%, the theoretical catalyst loading is 0.5mg/cm². However, by reducing the number of pulse cycles, lower loadings are also possible. The catalytic properties of the electrode were first recorded in nitrogen-purged 0.5M H2SO4 by plotting current density-potential curves and cyclic voltammetry. Very good activity or low overvoltage with respect to the OER was observed. Measurements for the ORR in oxygen-purged H2SO4 are still pending. To gain insight into the performance of the prepared oxygen electrodes, the prepared MEAs with an electrode area of 25cm² will be investigated in a hydraulically pressed test system. Figure 1

(Digital Presentation) Anti-Corrosion Investigation of Titanium Electrode for Cu Plating

For the plating of Cu in many industrial applications, Ti metal is commonly used as the cathode for the reduction of Cu. Titanium metal is known to exhibit adequate corrosion resistance due to the formation of a thin passivation layer on the surface. Under an acidic and high temperature environment, the passivation layer on the surface of the titanium metal tends to react with acidic solution. In other words, Ti metal tends to be corroded in an acidic environment. The corrosion behavior of commercial pure titanium in acid copper sulfate baths was investigated in this study. Available surface treatments were applied to suppress the corrosion of titanium passive layer. The microstructure of titanium metal after immersion in acid copper sulfate solution was examined by using SEM and FIB. The pitted and corroded Ti was clearly observed using SEM. The corrosion mechanism of the titanium metal in the sulfuric acid solution was discussed. In addition, the electrochemical characteristics of commercial pure titanium metal in sulfuric acid solution were also analyzed using the three-pole potential measurement method.

Anti-infective DNase I coatings on polydopamine functionalized titanium surfaces by alternating current electrophoretic deposition

Implant-associated infections (IAIs) can cause serious problems due to the difficult-to-treat nature of the biofilms formed on the implant surface. In mature biofilms, the matrix, which consists of polysaccharides, proteins, lipids and extracellular DNA (eDNA), forms a protective environment for the residing bacteria, shielding them from antibiotics and host defenses. Recently, the indirect prevention of biofilm growth through the degradation of eDNA using an enzyme, such as deoxyribonuclease (DNase) I, has gained attention and is regarded as a promising strategy in the battle against IAIs. In this study, coatings of DNase I were applied on titanium implant materials and their anti-infective properties were investigated. First, the effectiveness of alternating current electrophoretic deposition (AC-EPD) as a novel processing route to apply DNase I on titanium was examined and compared with the commonly applied diffusion methodology (i.e. classic dipping). For the same processing time, the use of AC-EPD in combination with a polydopamine (PDA) coupling chemistry on the titanium electrode surface significantly increased the protein deposition yield as compared to classic dipping, thereby yielding homogeneous coatings with a thickness of 12.8 nm and an average surface roughness, Sa, of ∼20 nm. X-ray photoelectron spectroscopy confirmed the presence of peptide bonds on all DNase-coated substrates. Time-of-flight secondary ion mass spectrometry detected a more dense DNase I layer in the case of AC-EPD for electrodes coupled as anode during the high-amplitude half cycle of the AC signal. The enzyme activity, release kinetics, and shelf life of DNase I coatings were monitored in real-time using a quantitative qDNase assay. The activity of DNase I coatings produced using AC-EPD was three time higher than for coatings prepared by classic dipping. For both deposition methods, a high initial burst release was observed within the first 2 h, while some activity was still retained at the surface after 7 days. This can be explained by the stable attachment of a small fraction of DNase to the surface through covalent bonding to the PDA layer, while superimposing DNase deposits were only loosely bound and therefore released rapidly upon immersion in the medium. Interestingly, coatings prepared with AC-EPD exhibited a prolonged, gradual release of DNase activity. The AC-EPD DNase coatings significantly reduced biofilm formation of both Staphylococcus epidermidis and Pseudomonas aeruginosa up to 20 h, whereas DNase coatings prepared by short classic dipping only reduce S. epidermidis biofilm formation, and this to a lesser extent as compared to AC-EPD DNase coatings. Overall, this study indicates that AC-EPD allows to rapidly concentrate DNase I on PDA-functionalized titanium, while maintaining the enzyme activity and anti-infective ability. This highlights the potential of AC-EPD as a time-efficient coating strategy (as opposed to the much slower dip-coating methodologies) for bioactive molecules in a wide variety of biomedical applications.

Recovery of “Hard-to-Recover” Selenate Ions in Sulfuric Acid Solutions during Polarization of Titanium Electrodes by Industrial Alternating Current

The article is devoted to the study of selenium (VI) reduction processes in sulfuric acid solutions when titanium electrodes are polarized by alternating current of industrial frequency (50 Hz). It was found that selenate ion reduction occurs on the surface of titanium electrodes in the cathode half-cycle of alternating current (practically at the cathode) by reaction: SeO42−+ 6e + 8H+ → Se + 4H2O. In addition, the recovery is carried out by titanium (III) ions: 6Ti3+ SeO42−+ 8H+ → Se + 6Ti4+ + 4H2O. It has been established that titanium (III) ions are products of dissolution of titanium during polarization by alternating current, so they can be formed by reaction: 2Ti + 6H+ → 2Ti3+ + 3H2. Reduction in selenate ions during polarization by alternating current can also occur due to the cementation reaction with titanium: 3Ti + 2SeO42− + 16H+ → 2Se + 8H2O + 3Ti4+. It was shown for the first time that the selenate ion is reduced to form a dispersed selenium powder with a high current efficiency. Depending on the conditions, both amorphous and crystalline selenium modifications are produced.

Electrochemical Mechanism of the Preparation of High-Purity Indium by Electrodeposition.

Indium is a crucial material and is widely used in high-tech industries, and electrodeposition is an efficient method to recover rare metal resources. In this work, the electrochemical behavior of In3+ was investigated by using different electrochemical methods in electrolytes containing sodium and indium sulfate. Cyclic voltammetry (CV), chronoamperometry (CA), and alternating current impedance (EIS) techniques were used to investigate the reduction reaction of In3+ and the electrocrystallization mechanism of indium in the indium sulfate system. The cyclic voltammetry results showed that the electrodeposition process is irreversible. The average charge transfer coefficient a of In3+ was calculated to be 0.116 from the relationship between the cathodic peak potential and the half-peak potential, and the H+ discharge occurred at a higher negative potential of In3+. The nucleation mechanism of indium electrodeposition was analyzed by chronoamperometry. The mechanism of indium at potential steps of −0.3 to −0.6 V was close to diffusion-controlled instantaneous nucleation with a diffusion coefficient of 7.31 × 10−9 cm2 s−1. The EIS results demonstrated that the reduction process of In3+ is subject to a diffusion-controlled step when pH = 2.5 and the applied potential was −0.5 V. SEM and XRD techniques indicated that the cathodic products deposited on the titanium electrode have excellent cleanliness and purity.

On the specific limitations of titanium electrodes in the electrocoagulation process

The comparative electrocoagulation treatments of two representative samples, a colloidal dispersion and a soluble dye, have been investigated within the same conditions in the presence of titanium and aluminum plates. The results indicate that behaviors specific to titanium electrodes contribute to reduce significantly the effectiveness of the electrocoagulation process. Contrarily to aluminum, a sufficient release of coagulants is inhibited during titanium anode dissolution due to enhanced anodization and dense, close-packed, titanium-based precipitates are formed together with stable titania nanoparticles causing a persistent turbidity in the bulk that makes separation more difficult.

Production of Copper Powders by Alternating Current Polarization of a Copper–Titanium Electrode Pair

Production of Copper Powders by Alternating Current Polarization of a Copper–Titanium Electrode Pair

ELECTROCHEMICAL DISSOLUTION OF TITANIUM ELECTRODES POLARIZED BY ALTERNATING CURRENT IN A HYDROBROMIC ACID AQUEOUS SOLUTION

The work shows the patterns of electrochemical dissolution of titanium electrodes polarized by alternating current in an aqueous solution of hydrogen bromide. The current density (200-1200 A/m2), hydrogen bromide concentration (1.0-5.0 M), electrolysis duration (0.25-2.0 hours), and electrolyte temperature depend on the current rate of the titanium electrode in the alternating current source (20°C-80°C) were considered. The maximum value of current yield was obtained at a current density of 400 A/m2 when titanium electrodes were polarized by an alternating current and it was recorded that the current yield is reduced at a high current density. It is shown that the current output for titanium increases directly proportional to the concentration of hydrogen bromide, i.e., hydrogen ion content. The order of the reaction which occurs during the electrolysis of hydrogen bromide is determined. It is proved that the current efficiency of dissolving titanium in the alternating current source decreases when the electrolysis time is increased, as the electrolysis products in the electrolyte settle down on the electrode surface. It is shown that as the temperature of the electrolyte solution is increased, the current output value for dissolving titanium rises to 48%. The activation energy determined according to the temperature-kinetic regime was 17.76 kJ/mol, the process was carried out according to the diffusion-kinetic regime. It was shown that titanium is dissolved in hydrogen bromide aqueous solution to form titanium (III) ions. The influence of the main parameters on the electrochemical dissolution of a polarized alternating current titanium electrode in hydrochloric acid is investigated and effective ways of titanium dissolution are considered. The results of the research can be used to propose a new method of titanium waste recycling and increase the potential of titanium electrode usage in production.

HYDROGEN’S EVOLUTION ON TITANIUM ELECTRODE FROM SULFURIC ACID SOLUTION

Thanks to the unique combination of physicochemical properties, metal hydrides (MH) are widely used in various fields of science and technology. High thermal, chemical and radiation resistance MH allows it to be used in nuclear industry as a material for nuclear reactors, chemical engineering, metallurgy for the production and refining of metals, for the production of devices operating at elevated temperatures and in adverse conditions. Unique properties MH are widely used in hydrogen energy as hydrogen storage, in rechargeable batteries. Analysis of literature data has shown that most studies are devoted to the practical use of the unique MH ability of reversibly absorbs a large amount of hydrogen. However, the electrochemical characteristics of the electrode processes of metal hydride systems were practically not investigated.&#x0D; The aim of this work is to study the processes that take place on the titanium electrode in sulfuric acid solutions, and the composition of titanium compounds that are formed. The paper presents the results of studies of the hydride formation reactions occurring on a polarized titanium cathode in aqueous solution 2 N sulfuric acid. The study was carried out using the following methods: the cyclic voltammetry and the method of x-ray phase analysis of the composition of the surface. It has been found that the reduction of hydrogen at the titanium cathode from a solution of sulfuric acid is accompanied by the formation of hydrides, which causes an increase in the overvoltage of hydrogen evolution and high values of the angular coefficients of the Tafel dependence. The kinetic parameters of this process have been calculated: the transfer coefficients α, theoretical and experimental angular coefficients btheor and bexp , exchange currents ie, the dependence of the hydrogen overvoltage from temperature. It has been found that exchange current density of hydrogen evolution reaction in this system is close by value to the current exchange of hydrogen evolution at the noble metals Pd, Pt, Rh, Ir and are (2,70∙÷0,8)∙10-3А·sm-2 in the temperature range 298 ÷ 343 K. The value of activation energy of 19,83 kJ mol-1 indicates the diffusion control of this process.

Electro-oxidation of tannery wastewater to achieve zero discharge – a step towards sustainability

ABSTRACT Pilot-scale electro-oxidation equipment with a functional capacity of 0.2 m3/hr, with titanium electrodes coated with TiO2/RuO2/IrO2 as both anodes and cathodes, was designed. It was installed on the premises of a commercial tannery. The waste streams from all the unit processes were combined. The composite wastewater, after conventional pre-treatment was subjected to electro-oxidation. The treated wastewater was reused four times with intermittent electro-oxidation treatment, after each reuse. EO could bring about a significant reduction in pollution load. Reduction in BOD, COD, TKN and TSS was 92%, 87.5%, 96.2% and 94.6% respectively. Generation of oOCl radicals, during electro-oxidation, were ascertained with DMPO-spin trapping techniques using Electron Spin Resonance (ESR) spectroscopy. The characteristics of the treated wastewater indicated that the wastewater was fit for reuse. No significant change in the quality of the water after each reuse was observed. The physical properties of the leathers obtained following the reuse processes were akin to those of the control leathers, which was indicative that the reuse did not cause adverse quality deviations. This technique could provide the plausibility for minizine the discharge of wastewater to near-zero level.

Design principles for the fabrication of high-performance cathode-electrolyte interphase for Li-ion batteries

Cathode-electrolyte interphase (CEI) is vital to the safety and lifespan of high-voltage cathode materials. However, the CEI formation mechanism in Li-ion batteries remains unclear. In a recent Matter article, Zhang et al. report on a real-time formation mechanism. Here, we discuss challenges and propose design principles in the fabrication of high performance CEI. Cathode-electrolyte interphase (CEI) is vital to the safety and lifespan of high-voltage cathode materials. However, the CEI formation mechanism in Li-ion batteries remains unclear. In a recent Matter article, Zhang et al. report on a real-time formation mechanism. Here, we discuss challenges and propose design principles in the fabrication of high performance CEI. In situ TEM visualization of LiF nanosheet formation on the cathode-electrolyte interphase (CEI) in liquid-electrolyte lithium-ion batteriesZhang et al.MatterFebruary 7, 2022In BriefThe formation behaviors of LiF nanocrystals have been studied on anodes in Li-ion batteries; there is no research work reporting LiF crystal growth on cathodes. Here, we report a real-time LiF crystal formation on positively charged titanium (Ti) electrodes in an electrochemical liquid cell with 150-nm-thick Li hexafluorophosphate (LiPF6)/propylene carbonate (PC) liquid electrolyte loaded. The LiF nanocrystals show two-dimensional (2D) morphologies on the electrode surface, which can serve as a cathode electrolyte interface (CEI). Full-Text PDF