Initial Metal Research Articles

Restructuring Electrolyte Solvation by a Versatile Diluent Toward Beyond 99.9% Coulombic Efficiency of Sodium Plating/Stripping at Ultralow Temperatures.

The reversible and durable operation of sodium metal batteries at low temperatures (LT) is essential for cold-climate applications but is plagued by dendritic Na plating and unstable solid-electrolyte interphase (SEI). Current Coulombic efficiencies of sodium plating/stripping at LT fall far below 99.9%, representing a significant performance gap yet to be filled. Here, the solvation structure of the conventional 1m NaPF6 in diglyme electrolyte by facile cyclic ether (1,3-dioxolane, DOL) dilution is efficiently reconfigured. DOL diluents help shield the Na+-PF6 - Coulombic interaction and intermolecular forces of diglyme, leading to anomalously high Na+-ion conductivity. Besides, DOL participates in the solvation sheath and weakens the chelation of Na+ by diglyme for facilitated desolvation. More importantly, it promotes concentrated electron cloud distribution around PF6 - in the solvates and promotes their preferential decomposition. A desired inorganic-rich SEI is generated with compositional uniformity, high ionic conductivity, and high Young's modulus. Consequently, a record-high Coulombic efficiency over 99.9% is achieved at an ultralow temperature of -55°C, and a 1 Ah capacity pouch cell of initial anode-free sodium metal battery retains 95% of the first discharge capacity over 100 cycles at -25°C. This study thus provides new insights for formulating electrolytes toward increased Na reversibility at LT.

Multigene genetic programming approach for modelling and optimisation of removal of heavy metals from ash pond water using cyanobacterial-microalgal consortium

ABSTRACT Heavy metals such as Lead(II), Nickel(II), Manganese(II), Cadmium(II), Chromium(VI), and others are leached from coal ash in thermal power plants, contaminating ash pond water and subsequently contaminating groundwater. Phycoremediation using microalgae or cyanobacteria is an emerging technology to remove such heavy metals from ash pond water. The present study aims at development of an accurate data-driven Genetic Programing (GP) approach for modelling of the phycoremediation process for abatement of the above-mentioned heavy metals using a consortium comprising of a cyanobacterium Synechococcus sp. and green algae Chlorella sp. The developed model was used to find a relation between the average percentage removal of metals with all input parameters such as the initial metal concentrations, pH, and days. To maximise metal removal, Genetic Algorithm (GA) optimisation technique was applied to determine optimal values of input parameters. These optimum input parameters are difficult to get through experimentation using the trial and error method. The established modelling and optimisation technique is generic and can be applied to any other experimental study.

Competitive Effect of Zinc and Cadmium on the Biosorption of Chromium by Orange Waste

Batch experiments were conducted to test orange waste (OW), an agricultural solid waste byproduct from the orange juice manufacturing industry, as adsorbent for binary solutions of Cd2+-Cr3+ and Zn2+-Cr3+. Fourier transform infrared spectroscopy (FTIR) and the point of zero charge (pHpzc) were used to identify the functional groups on the OW surface involved in biosorption. The biosorption equilibrium data for both binary-metal solutions were obtained and fitted to various isotherm models. The extended Sips and the non-modified Redlich-Peterson isotherm models gave the best fit for the experimental data. According to the extended Sips model, the maximum biosorption capacity of OW was 0.573 mmol·g−1 for Cd2+, 0.453 mmol·g−1 for Zn2+, and 1.96 mmol·g−1 for Cr3+. The sorption capacity dropped to 0.061 mmol·g−1 for Cd2+ and to 0.101 mmol·g1 for Zn2+ in their binary systems with Cr3+ for the higher initial metal concentrations in the solution. However, the maximum sorption capacity of chromium was only slightly affected by the presence of Cd2+ or Zn2+. For both binary systems, the presence of a second metal ion in the solution always conduces to a reduction in the sorption of the other metal in the solution. The presence of Cr3+ decreased the sorption of Cd2+ and Zn2+ more than vice versa. Conclusively, effective removal of Cr3+ ions from an aqueous solution can still be achieved in the presence of Cd2+ or Zn2+.

Kinetic and Equilibrium Modelling of Lead, Zinc and Copper Ions Sorption from Aqueous Solution Using Charcoal Fines

The potential of chemically modified charcoal fines UCF (unmodified charcoal fine) and MCF (modified charcoal fines) as low cost adsorbents for the removal of Pb2+, Cu2+ and Zn2+ ions from aqueous solution was studied. MCF was prepared by chemical modification of UCF with HNO3 and KOH followed by pyrolysis. The factors influenced the effectiveness of biosorption process were pH, contact time, initial metal concentration, temperature and adsorbent dosage. FT–IR spectra confirmed the existence and interaction of the adsorbents with the effluent pollutants. MCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 5, 35 0C, 90 minutes, 15 mg/L and 2 g, respectively. UCF exhibited optimum pH, temperature, contact time, initial metal ion concentration and biosorbent dosage values of 6, 35 0C, 100 minutes, 20 mg/L and 2.5 g, respectively. The adsorption isotherm modelling using both adsorbents showed that the equilibrium data conformed more to Langmuir than the Freundlich model. Kinetic studies showed that the adsorption processes followed a pseudo-second order kinetic model. Thermodynamic studies confirmed the spontaneity and feasibility of the adsorption process. The results showed that both adsorbent have the potential to be applied as alternative low cost biosorbent.

Alternating Direct Current Field Assistant Promoting Chemical Stabilization of Combined Heavy Metals Contaminated Soil

To enhance the remediation efficiency and reduce the chemicals consumption, the combined heavy metals Lead (Pb), Copper (Cu) and Cadmium (Cd) contaminated soil were stabilized by chemical passivators with alternating direct current field (ADC) assistant. The results showed that ADC treatment activated initial heavy metal compounds in the soil. The leaching concentrations of Pb, Cu and Cd in soil under ADC condition increased by 19.61%, 38.77% and 49.10% in comparison with no electric field, respectively. The exchangeable fractions of Pb, Cu and Cd increased while the reducible, oxidizable and residual fractions decreased substantially. Thus, the chemical passivators addition companied with ADC treatment in the beginning increased stabilization efficiency of heavy metals in the soil and reduced over 30% amount of chemical agent consumption, comparing with only chemical passivator stabilization. The mechanism can be speculated that ADC assistant facilitated more heavy metal ions in the soil reacting with phosphorus- containing passivator to formed more complex and stable metal phosphates. It was confirmed by XRD measurement that silicon element in the crystal structure of metallic compound was replaced by phosphorus element.

Non-derivatizing solvent assisted waste-derived cellulose/ MOF composite porous matrix for efficient metal ion removal: comprehensive analysis of batch and continuous packed-bed column sorption studies.

The use of metal-organic frameworks (MOFs) for wastewater treatment in continuous operation is a major challenge. To address this, the present study demonstrates the eco-friendly and economic synthesis of Ca-MOF immobilized cellulose beads (Ca-MOF-CB) derived from paper waste. The synthesized Ca-MOF-CB were characterized using standard analytical techniques. Batch sorption studies were performed to check the effect of cellulose composition (wt%), Ca-MOF loading, contact time, and initial metal ion (Pb2+, Cd2+, and Cu2+) concentration. Ca-MOF-CB beads exhibited outstanding equilibrium sorption capacities for Pb2+, Cd2+, and Cu2+, with estimated values of 281.22 ± 7.8, 104.01 ± 10.58, and 114.21 ± 9.68 mg g-1, respectively. Different non-linear isotherms and kinetic models were applied which confirmed the spontaneous, endothermic reactions for the physisorption of Pb2+, Cd2+, and Cu2+. Based on the highest equilibrium sorption capacity for Pb2+ ion, in-depth parametric column studies were conducted in an indigenously developed packed-bed column set-up. The effect of packed-bed height (10 and 20 cm), inlet flow rate (5 and 10 mL min-1), and inlet Pb2+ ion concentration (200, 300, and 500 mg L-1) were studied. The breakthrough curves obtained at different operating conditions were fitted with the empirical models viz. the bed depth service time (BDST), Yoon-Nelson, Thomas, and Yan to estimate the column design parameters. In order to determine the financial implications at large-scale industrial operations, an affordable synthesis cost of 1 kg of Ca-MOF-CB was estimated. Conclusively, the present study showed the feasibility of the developed Ca-MOF-CB for the continuous removal of metal ions at an industrial scale.

Enhanced Performance of the Composite of FeMgAl‐Layered Double Hydroxide and Rice Husk Biochar to Adsorb Heavy Metal Ions of Lead and Cadmium in Aqueous Solutions

The layered double hydroxide (LDH) of FeMgAl and its composite with the rice husk biochar (FeMgAl/RHB) was tried for the first time for removing heavy metal ions of lead (Pb2+) and cadmium (Cd2+) in batch tests. Scanning electron microscopy and Fourier transform infrared spectroscopy demonstrated that FeMgAl/LDH was successfully synthesized and integrated into RHB. Furthermore, the presence of Cd2+ and Pb2+ was confirmed by energy‐dispersive X‐ray spectroscopy, exhibiting an effective adsorption process. The equilibrium contact time was estimated at 15 and 60 min, for Pb2+ and Cd2+, respectively, with high removal efficiencies and adsorption capacities upon immediate contact. Within the observed range (0–100 mg·L−1) of initial metal concentrations, the removal efficiencies decreased constantly using both adsorbents, while 50 or 60 mg·L−1 of Pb2+ and Cd2+, respectively, was estimated as the optimum values due to a steady increase in the adsorption capacities with composite adsorbent presenting a better efficiency, twice of the metal uptake capacity compared with FeMgAl/LDH. The lowest used amount of each adsorbent (0.05 g) exhibited highest adsorption capacity which decreased with increasing amount of adsorbent (up to 0.8 g), whereas the removal efficiencies increased for both heavy metal ions. A solution of pH value 0.7–0.8 was estimated as an optimum value with a uniform increasing pattern of adsorption capacities and percentage removal of both heavy metal ions using the FeMgAl/LDH as well as the composite adsorbent. A perfect fitting of the adsorption data was seen using the pseudo‐second‐order kinetic model, suggesting the chemical sorption to be the control mechanism of adsorption. The fitting of the Langmuir and Temkin isotherm models proposed a monolayer as well as heterogeneous adsorption system. The same was further confirmed based on the reasonable fit of both (Sips and Redlich–Peterson) three‐parameter isotherms in addition to a physical adsorption system, as suggested by the Dubinin–Radushkevich isotherm model.

A Study of Primordial Very Massive Star Evolution. II. Stellar Rotation and Gamma-Ray Burst Progenitors

We calculate new evolutionary models of rotating primordial very massive stars, with initial mass from 100 M ⊙ to 200 M ⊙, for two values of the initial metallicity Z = 0 and Z = 0.0002. For the first time in this mass range, we consider stellar rotation and pulsation-driven mass loss, along with radiative winds. The models evolve from the zero-age main sequence until the onset of pair-instability. We discuss the main properties of the models during their evolution and then focus on the final fate and the possible progenitors of jet-driven events. All tracks that undergo pulsational-pair instability produce successful gamma-ray bursts (GRB) in the collapsar framework, while those that collapse directly to black holes (BH) produce jet-driven supernova events. In these latter cases, the expected black hole mass changes due to the jet propagation inside the progenitor, resulting in different models that should produce BH within the pair-instability black hole mass gap. Successful GRBs predicted here from zero metallicity, and very metal-poor progenitors, may be bright enough to be detected even up to redshift ∼20 using current telescopes such as the Swift-BAT X-ray detector and the JWST.

In situ construction of heterostructured CuxO@NiCoS nanoarrays for alkaline overall water splitting

The synergistic effect and the optimization of the initial metal source ratio significantly improve the electrocatalytic performance of heterostructured CuxO@NiCoS bifunctional electrocatalysts.

Biosorption studies on arsenic (III) removal from industrial wastewater by using fixed and fluidized bed operation

Previously, activated carbon was used as adsorbent for the removal of heavy metals at batch scale and the reported removal efficiency was up to 25 % (while in our technique the efficiency is up to 75%). The large industries operate with continuous processes and discharge large amount of wastewater containing heavy metals. No research was published for continuous operation using fluidized bed adsorption column till now. The novelty of this study is on the mode of operation (continuous operation at large scale under fixed and fluidized bed conditions), Biosorbent activated carbon (AC), and maximum efficiency of arsenic removal (i.e. 75 %). The Biosorbent activated carbon prepared from waste agriculture material. Industrial wastewater consists of many inorganic and organic pollutants which are discharged into water bodies resulting the serious health problems. Now a days, concentration of arsenic has much increased as compared to the permissive concentration level (25mg/L). Therefore, there is need to reduce this concentration up to threshold value (10μg/L). The use of biosorbents for arsenic removal from wastewater has global significance due to its widespread availability and low cost. Biosorption of Arsenic strongly depends on the initial metal concentration, contact time, speed of stirring, pH and temperature. The maximum arsenic as (III) removed at pH-7.5 is 70%, it was improved to 83% by agitation in batch experiments. While in continuous mode experiments (Fixed bed) the bed height and flow rates were varied. At the Fluidized bed experiments, the maximum As (III) removed was 75%. The effects of several factors such as pH, initial solute concentration, biosorbents dose, has been revaluated in this paper. The low cost, easily available biosorbent AC is recommended for removal of arsenic from contaminated wastewaters to bring them in compliance.

Enhanced chromium (VI) removal: A remediation study employing nano zero-valent iron supported by sawdust

The rapid expansion of industry leads to the emission of heavy metals into the environment, posing a significant global concern presently. The management of heavy metals holds particular significance due to their resilience and persistence in the environment. Removal technologies of heavy metals include physical and chemical treatments. Chromium (VI) was utilized as a representative of heavy metals in this research. Sorption experiments were conducted using a composite material consisting of supported nano zero-valent iron on sawdust, designated as NZVI/SD. The NZVI/SD composite was prepared through a two-step process involving the impregnation of sawdust with ferrous sulfate, followed by a chemical reduction using Sodium borohydride (NaBH4). The adsorbent was characterized with the help of Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-Ray Diffraction analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and chemical test. The adsorption characteristics have been investigated under various conditions, including different pH values, adsorbent dosages, initial metal ion concentrations, contact times, and varying temperatures. The optimal conditions for employing NZVI/SD for the removal of Cr(VI) were observed at a pH of 3.0, an adsorbent dosage of 0.5 g/L, an initial metal ion concentration of 61.45 mg/L, a contact time of 180 min, and a temperature of 50 °C. Sorption of Cr(VI) on NZVI/SD followed Langmuir Isotherm model. The maximum monolayer sorption capacity on NZVI/SD was 39.8 mg/g at 298 K temperature (equilibrium pH of 3.0) estimated from the Langmuir isotherm. Kinetics and thermodynamic studies on the sorption of Cr (VI) on NZVI/SD were done to understand the sorption mechanism. Sorption kinetics of Cr (VI) on NZVI/SD confirmed that pseudo second order reaction kinetics was followed concluding that the rate of adsorption depends on the analyte and the available free site of adsorbent. By employing the Langmuir isotherm model and Van't Hoff equation, the determination of thermodynamic parameters such as Gibbs free energy, enthalpy change, and entropy change of the adsorption process was facilitated. It was found that the sorption of Cr(VI) was spontaneous (∆G° = −10.36 kJ.mol−1) on NZVI/SD and the process was endothermic (∆H = +4.609 kJ/mol). NZVI/SD can be effectively regenerated by elution with 1 M NaOH for 4 h.

Conversion of carbon black recovered from waste tires into activated carbon via chemical/microwave methods for efficient removal of heavy metal ions from wastewater.

In this research study, recovered carbon black (rCB) was obtained via pyrolysis of waste tires. The obtained rCB was then converted into activated carbon species through both chemical treatment and microwave coupled with chemical treatment as a two-step activation process. The activated carbon obtained from chemical activation was denoted as C-AC, while that obtained from exposure to microwave followed by chemical activation was labeled as MC-AC. These two structures were consequently introduced as sorbents for the removal of cadmium ions from an aqueous solution. The structural characteristics of the introduced adsorbents were confirmed using various techniques, namely X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray (EDX) spectroscopy. Additionally, textual features of these adsorbents were acquired via both scanning electron microscopy (SEM) and N2 adsorption-desorption BET surface area analyses. These two structures were then introduced for Cd ion adsorption under different operating conditions. Particularly, the effect of pH, contact time, adsorbent dose, and metal ion concentration on the efficiency of adsorption was investigated. The 1maximum adsorption capacity was detected at a pH value of 5.0, a contact time of 30 min, a sorbent dose of 0.4 g L-1, and an initial metal concentration of 50 mg L-1 using MC-AC, which exhibited nearly double the sorption capacity detected for C-AC. Kinetic studies indicated that the process of Cd(ii) adsorption is perfectly described and fitted by the pseudo-second-order model. However, adsorption isotherms for the two adsorbents were found to match the Langmuir model, referring to the occurrence of uniform monolayer adsorption for the metal ions. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and endothermic.

Adsorptive removal of heavy metal ions from model aqueous media using titanium metal-organic framework and its polyvinyl chloride functionalized composite

The present study was conducted on Ti-MOF and its PVC functionalized composite with the objective of toxic heavy metal ions removal from aqueous media. For achieving this purpose, the solvothermal method was used to synthesis Ti-MOF which was then functionalized with PVC for composite synthesis. The synthesized adsorbent materials were then analyzed via different techniques that include the FTIR, XRD, SEM and EDX analysis along with TGA and point of zero charge (PZC). Batch experiments were conducted for nickel (Ni) and copper (Cu) metal ions sorption from water, using the synthesized adsorbents, under different experimental conditions like initial metal ions concentration, pH, adsorbent’s dosage, time of contact and temperature. The sorption of heavy metal ions by the adsorbents was increased with increasing the media dosage and concentration. Whereas, increasing the pH of the system, from pH-2 to pH-10, also enhanced the sorption phenomenon, because of the pronounced forces of attraction between the positively charged adsorbate ions and the adsorbent’s negatively charged surface, accompanied by precipitation at a much higher pH. It was observed that the adsorption on the functionalized adsorbent surface was greater than the parent MOF material because of the availability of a greater number of adsorption sites, increasing the adsorption capacity of Ni ions from 6.436 to 29.2 mg/g and that of Cu ions from 21.414 to 41.616 mg/g. In addition, the composite material was found to have greater affinity towards Cu metal ions as compared to Ni metal ions, which is attributed to the smaller size of Cu metal ions as compared to Ni ions. To determine the adsorption mechanism, various adsorption isotherms were examined. The results concluded that the Langmuir adsorption isotherm was the suitable model to explain the adsorption mechanism.Moreover, thermodynamic parameters like Gibbs free energy (, change in enthalpy, along with the change in entropy, were determined. The sorption process was found to be more spontaneous at lower temperatures, with the exothermic nature of adsorption, in the case of Ni metal ions and the endothermic nature in the case of Cu metal ions.Also, the negative value of ΔS in case of Ni ions adsorption accounts for the decreased disorderliness of the system which is also the opposite tothat of Cu ions adsorption onto the surface of Ti-PVC composite.The PVC functionalized Ti-MOF was thus found to be an effective, durable, and environmentally friendly adsorbent, for the sorption of heavy metal ions from wastewater.

Adsorptive Removal of Lead (II) Pollutants from Wastewater Using Corncob-Activated Carbon

he level of contamination in industrial wastewater has been a serious environmental challenge of our time. Various researchers have reported that the adsorption process using different adsorbents is a promising technique for treating heavy metal-contaminated wastewater. This study investigated the adsorptive removal of lead (II) from wastewater using corncob-activated carbon. Activated carbon was synthesized from a raw corncob. The synthesized activated carbon was applied as a sorbent in batch lead (II) adsorption in an aqueous lead (II) solution. Scanning electron microscopy, Fourier transformed infrared (FTIR), and Brunauer–Emmett–Teller (BET) theory characterized the synthesized activated carbon. A batch adsorption study investigated the effects of dosage, contact time, and the initial concentration of lead (II) on the sorption of Pb2+ on the synthesized activated carbon. The highest removal of lead recorded was 95 % at an adsorbent dosage of 2.5 g/L in 2 h. The highest adsorption capacity was 16.46 mg/g at the same conditions. The results showed that percentage removal increased with dosage and contact time but decreased with the initial metal ion concentration. Adsorption kinetics were best described with the pseudo-second-order kinetics, while the Langmuir isotherm model best fitted equilibrium adsorption in the study. The FTIR results showed the presence of several functional groups like carboxyl, hydroxyl, and amino, indicating good interaction with lead metal ions. The BET characterization revealed the activated corncob’s specific surface area and pore volume to be 249 m2/g and 0.164 cm3/g. This work shows that activated carbon can be synthesized from agricultural waste such as corncob and be used as an effective adsorbent for heavy metal removal, such as lead, from wastewater.

Co-digestion potential of different industrial sludge sources and impact on energy recovery

Co-digestion potential of the wastewater treatment sludges produced at two industries with different characteristics was investigated in anaerobic batch reactors operated at mesophilic (35±2 °C) condition. The sludge sources selected were from a food industry producing edible oil and from a textile industry producing woven fabric. Reactor performance was evaluated by the conventional parameters as well as by monitoring the biogas production during co-digestion of both industrial sludges at equal mixing proportions. Results indicated that both of these sludge sources had substantial biogas production potential with a cumulative biogas yield more than 425 mL/g-VSSfed whereas it was about 5-fold lower only for the food sludge. On the other hand, chemical oxygen demand (COD) removal reached to about 90% during co-digestion with a well recovery of pH value and alkalinity concentration for sufficient buffering at the end of incubation. Therefore, by the combination of different industrial sludges through co-digestion; higher digestion performance and improved methane yield could be achieved due to better balanced substrate and nutrients. Regarding the initial heavy metals in the supernatant phase of the mixed sludge; iron (Fe), zinc (Zn), nickel (Ni), aluminum (Al), and manganese (Mn) could be removed from 56% to 80% while no apparent removals were observed in cadmium (Cd) and lead (Pb) at the end of operation. Hence, these potential toxic pollutants in the digestate should be taken into consideration while deciding the most appropriate resource recovery and ultimate disposal methods.

Sulu Çözeltilerden Civa(II) İyonlarının Adsorpsiyonunda Hidroklorik Asit İle Modifiye Edilmiş Kilin Kullanılması

With their natural abundance and minimal processing requirements, clays hold the potential to serve as economical adsorbents for various heavy metals. In this research, the adsorption capacity of hydrochloric acid (HCl) modified clay to adsorb mercury(II) (Hg2+) ions from aqueous solutions was investigated. The parameters affecting the adsorption capacity were determined by studying the initial metal ion concentration, contact time, and temperature effects. For natural clay, an optimal initial concentration of 400 mg/L and a contact time of 50 minutes were identified. Meanwhile, modified clay showed best results with an initial concentration of 400 mg/L and a contact time of 60 minutes for Hg2+ ions. The analysis of isotherm data revealed that the Langmuir isotherm model exhibited the best fit for both materials in Hg2+ ion adsorption. At temperatures of 298 K, 308 K, and 318 K, the adsorption capacity for natural clay and Hg2+ ions were found to be 4.56, 5.01, and 5.08 mg/g, respectively. Meanwhile, the modified clay displayed adsorption capacities of 11.12, 11.37, and 12.30 mg/g for Hg2+ ions at the same temperatures. Additionally, the kinetic analysis determined that the pseudo-second-order kinetic model was the best fit for both materials in Hg2+ ion adsorption. The adsorption experiments investigated the adsorption mechanisms of Hg2+ metal ions on both natural clay and modified clay, with results indicating that the modified clay had a higher adsorption capacity for metal ions compared to the raw clay.

Investigation of physical, chemical, and technological properties of titanium powder obtained by thermal dehydrogenation in vacuum

In recent times, there has been significant interest in powder metallurgy, driven primarily by the active development of additive manufacturing. Consequently, a pressing task is the development of methods for producing initial metal powders that are cost-effective while meeting high consumer standards. This research is a continuation of studies on titanium powders obtained through SHS hydrogenation and thermal dehydrogenation. The titanium hydride powders, previously obtained using SHS technology, were sieved, resulting in fractions that matched the granulometric composition of titanium powders of PTK, PTS, PTM, and PTOM grades. Subsequently, the titanium hydride powder samples underwent dehydrogenation through vacuum annealing in an electric resistance furnace. Throughout the dehydrogenation process, the kinetics of hydrogen release from the titanium powder were examined as a function of particle size. The macro- and microstructure, chemical composition, and technological properties of the dehydrogenated powders were thoroughly analyzed. It was determined that the titanium powder maintained its original polygonal fragmented shape after dehydrogenation. The average particle size decreased by 5–20 %, and “satellites” were observed on larger particles. Chemical analysis revealed that larger samples contained a higher level of residual hydrogen and gas impurities (Σ 0.77 wt. %) compared to finer powders (Σ 0.26 wt. %). Regarding the study of technological properties, the resulting powders exhibited the necessary characteristics for use in titanium powder metallurgy, with the exception of low flowability due to the particle shape and microstructural heterogeneity). In conclusion, this research has demonstrated the potential of the SHS hydrogenation and thermal dehydrogenation method in producing high-quality titanium powders.

Application of multigene genetic programming and water evaporation optimization technique for modeling and optimization of removal of heavy metals from ash pond water using cyanobacterial consortium

Abstract Heavy metals such as Lead(II), Nickel(II), Manganese(II), Cadmium(II), Chromium(VI), etc., are leached from the coal ash of thermal power plants. These metals contaminate ash pond water and subsequently contaminate groundwater. Phycoremediation using microalgae/cyanobacteria is an emerging technology for removal of heavy metals. The present study aims at phycoremediation of the said heavy metals from ash pond water using cyanobacterial consortium of Limnococcus limneticus and Leptolyngbya subtilis followed by the development of an accurate data-driven Multigene Genetic Programing (MGGP) approach for modeling and optimization of the process. The developed model was used to obtain a correlation between the average removal of metals and biomass production with all input factors such as the initial metal concentrations, pH, and days of incubation. To maximize metal removal and biomass production, the Water Evaporation Optimization (WEO) technique was applied to determine optimal values of input parameters. The application of WEO for the optimization of the phycoremediation process is the first of its kind and here lies the novelty of the study.

(Battery Division Early Career Award Sponsored by Neware Technology Limited) Understanding Interfacial Mechanisms that Govern Performance in Solid-State Batteries

Solid-state batteries offer the promise of improved energy density and safety compared to lithium-ion batteries. Here, I will present our emerging understanding of the key differences between how high-capacity anode materials behave in solid-state batteries compared to in conventional liquid-electrolyte batteries. The electro-chemo-mechanical evolution of materials at solid-solid electrochemical interfaces is different than at solid/liquid interfaces, and contact evolution in particular plays a critical role in determining the behavior of solid-state batteries. I will focus on mechanisms governing lithium metal anodes (including lithium in the “anode-free” configuration) and alloy anodes. Lithium metal anodes in solid-state batteries are intrinsically limited by void formation during stripping and dendrite growth during plating. Anode-free solid-state batteries, in which there is no initial lithium metal at the anode interface, offer extremely high energy density, but there is a lack of understanding of how their behavior differs from excess-lithium electrodes. Using X-ray tomography, cryo-FIB, and finite-element modeling, we show that anode-free solid-state batteries are intrinsically limited by current concentrations at the end of stripping due to localized lithium depletion. This causes accelerated short circuiting compared to lithium-excess cells. Based on these results, the beneficial influence of metal alloy interfacial layers on controlling lithium evolution and mitigating contact loss from localized lithium depletion, including at low stack pressures, will be discussed. X-ray tomography is further shown to be particularly useful in observing the dynamic evolution of lithium metal, including void formation and filament growth. The second part of the talk focuses on alloy anodes. Alloy anodes typically exhibit fast capacity decay in lithium-ion batteries because of excessive solid-electrolyte interphase growth. We show that alloy anodes in solid-state batteries can exhibit improved interfacial stability and enhanced cyclability. Furthermore, in situ measurement of stack pressure evolution during cycling shows that the volume changes of alloy anodes can lead to large pressure swings within the cell, giving insight into electrode composite evolution. Based on these insights, we present a new design for dense foil alloy anodes. This design offers a paradigm that does away with slurry coating, potentially reducing manufacturing costs. Taken together, these findings show the importance of controlling chemo-mechanics and interfaces in solid-state batteries for improved energy storage capabilities.

Metallic Nanoalloys on Vertical GaAs Nanowires: Growth Mechanisms and Shape Control of Ni-GaAs Compounds.

GaAs nanowires are promising candidates for emerging devices in a broad field of applications (e.g., nanoelectronics, photodetection, or photoconversion). These nanostructures benefit greatly from a vertical integration, as it allows for the exhibition of the entire nanowire surface. However, one of the main challenges related to vertical integration is the conception of an efficient method to create low resistive contacts at nanoscale without degrading the device performance. In this article, we propose a complementary metal-oxide-semiconductor (CMOS)-compatible approach to form alloyed contacts at the extremities of vertical GaAs nanowires. Ni-based and Pd-based alloys on different vertical GaAs nanostructures have been characterized by structural and chemical analyses to identify the phase and to study the growth mechanisms involved at the nanoscale. It is shown that the formation of the Ni3GaAs alloy on top of nanowires following the epitaxial relation Ni3GaAs(0001)∥GaAs(111) leads to a pyramidal shape with four faces. Finally, guidelines are presented to tune the shape of this alloy by varying the initial metal thickness and nanowire diameters. It will facilitate the fabrication of a nanoalloy structure with tailored shape characteristics to precisely align with a designated application.