Metal Chlorides Research Articles

The dissolution of galactomannans in type II/III deep eutectic solvents: Effect of polysaccharide structure and interaction mechanism

Deep eutectic solvents (DESs) have garnered increasing attention as sustainable solvents for natural polysaccharides. Galactomannans (especially guar and locust bean gums) are abundant natural compounds used in food, medicine, agriculture and daily chemical products, whereas their high molecular weight and randomly distributed non-linear structures remain a huge challenge in solubilization and high value-added utilization. In this study, the dissolution of galactomannans in type II/III DESs was comprehensively investigated using density functional theory (DFT) calculation, experimental results, and molecular dynamics simulation (MD). The results indicated that immense anionic and neutral H-bonds supported by type II DESs (consisting of a quaternary ammonium salt and a metal chloride hydrate) could break and rebuild galactomannan H-bond networks, thereby exhibiting remarkable physical solubilization. A large number of active acid sites in type III DESs (consisting of a quaternary ammonium salt and a hydrogen bond donor) greatly improved solubility and cleaved the glycosidic bond, enabling the recovery of polysaccharides with a target molecular weight. Furthermore, significant correlations between solubility and the structure of galactomannans had been established, which meant that high molecular weight and rich galactose side-chains produced repulsive interactions with DESs, directly hindering dissolution. Overall, this work not only offered a framework for enhancing the dissolution of polysaccharides, but also proposed a promising strategy for development of task specific DESs promoting green chemistry and the use of sustainable bioresources.

Cerium rare-earth ions reinforced built-in electric field to enable efficient carrier extraction for highly efficient and stable perovskite solar cells

Perovskite solar cells prepared by inorganic-organic three-dimensional hybrid have good power conversion efficiency, but their operational stability remains a major challenge for commercialization. The defect of perovskite is an important factor restricting its charge dynamics and stability. Here, the rare earth metal chloride CeCl3 is introduced into perovskite solution to passivate the defects, where the Pb2+ part of the B position is replaced by Ce3+. The prepared films have the characteristics of increasing grain size, enhancing carrier mobility and excellent crystallinity. Meanwhile, via passivating interface defects and improving carrier transport capacity, the generation of non-radiative recombination is reduced, the carrier migration length is extended, and the device performance is improved. The results show that the PCE of the standard device is only 65 % after 2880 h of N2 atmosphere at room temperature, while the efficiency of the device doped with CeCl3 can remain at 93 %. When the unencapsulated sample was placed in an air environment (40–60 % humidity), the control sample was reduced to 72 % at 1060 h, while the CeCl3 was maintained at 87 %. Additionally, the reduction of residual stress in the perovskite layer also provides good bending stability for the flexible target device. These results show that the incorporation of rare earth metal ions is an effective way to stabilize and improve the efficiency of the device.

Doping of Copper(I) Thiocyanate (CuSCN) with Metal Chlorides for p-Channel Thin-Film Transistors

Doping of Copper(I) Thiocyanate (CuSCN) with Metal Chlorides for p-Channel Thin-Film Transistors

Evaluation of the Interactions of Some Alkali and Alkali Earth Metallic Chlorides on Guaiacol Oxidation by Peroxidase from Watermelon Rind

Evaluation of the Interactions of Some Alkali and Alkali Earth Metallic Chlorides on Guaiacol Oxidation by Peroxidase from Watermelon Rind

Effects of Ethylenediaminetetraacetic Acid and Some Chlorides of Divalent Metals on the Initial Velocity of Crude Peroxidase from Watermelon Rind

Aim: This study investigated the effects of ethylenediaminetetraacetic acid (EDTA) and some chlorides of divalent metals on the initial velocity of crude peroxidase from watermelon rind Study design: In vitro enzyme assay. Place and Duration of Study: Department of Biochemistry, Faculty of Life Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria between September 2023 to November 2023. Methodology: The kinetics of the oxidation of Guaiacol by the crude peroxidase from the rind of watermelon in the presence of varying concentrations of EDTA and the chloride salts of iron, copper was determined spectrophotometrically by monitoring the oxidation of Guaiacol to produce a brown tetraguaiacol at a wavelength of 470nm. The various salt concentrations were varied between 0.5 mM and 3 mM. Each of the reaction mixtures used in the kinetic study comprised; 2.3 mL of 0.6 M sodium acetate buffer (pH 5.4), 0.2 mL of 0.02 mM Guaiacol, 0.1 mL of crude extract, 0.2 mL of varying concentration chloride salt, 0.2 mL of 2 mM of H2O2 added last to start the reaction. The final concentration of H2O2 in the 3 mL assay was 0.13 mM. The total volume of the reaction mixture was 3 mL. The absorbance was read every 2 seconds for one minute after adding hydrogen peroxide using a stop-clock. The control had no metal ion but replaced with distilled water Results: Results showed that EDTA reduced the activity of the enzyme in a concentration dependent manner. CuCl2 and FeCl2 activated the enzyme and FeCl2 being a better activator within the salt concentration range of 0.5 mM to 3 mM. Conclusion: These findings are of great importance to industries in understanding the mechanism of action of peroxidase from the rind of watermelon, especially as the search for cheap and alternative sources of peroxidases continues.

Ammonia Decomposition By Microwave Plasma Discharges

The global discourse focuses on future energy vectors, with hydrogen emerging as a robust candidate owing to its established industrial applications. However, a current challenge lies in storing and transporting hydrogen-based fuels. This research focuses on advancing efficient and environmentally friendly techniques for large-scale hydrogen production, leveraging its widespread industrial presence. Ammonia, identified as a promising energy vector, offers advantages in storage and transport over hydrogen. It capitalizes on existing global infrastructures, with approximately 20 million metric tons traded annually, contributing to a total production of 150 million tons annually. If many works focus on producing ammonia by electrical discharges [1], only a few are devoted to ammonia cracking and generally concentrate on catalysis [2]. In this study, we propose an investigation into the decomposition of ammonia by applying microwave (MW) plasma. Utilizing a MW cavity that confines an electromagnetic field excited at 2.45 GHz, we induce electrodeless plasma within a fused silica tube where pure ammonia (NH3) gas flow. At first, the plasma discharge was characterized with Fourier Transform Infrared Spectroscopy (FTIR). This preliminary part of the study exhibited that, for fixed input power (300 W) and fixed working pressure (100 mbar), NH3 decomposition decreased with a flow rate ranging from 0.4 to 2.4 SLM. It also showed that for fixed input power (300 W) and fixed flow rate (2.4 SLM), the NH3 dissociation increased with pressure ranging from 40 to 140 mbar. These experiments exhibited the predominant role of the residence time of ammonia but also reactive species in plasma. To further understand the NH3 cracking mechanisms, we performed optical emission spectroscopy (OES). This technique allowed us to determine the various light-emitting species produced during NH3 dissociation in the discharge and their physical parameters, such as temperatures and relative densities, as a function of different experimental parameters. We study the influence of gas flow rate ranging from 1 to 15 SLM, input power and near-atmospheric pressure on NH3 cracking and hydrogen (H2) recombination mechanisms. Gas chromatography (GC) was employed to measure the dissociation yield of NH3 and assess the efficiency of the H2 production process. In parallel, we synthesize iron (Fe) and nickel (Ni) nanoparticles through a plasma solution process. Both metals are abundant and inexpensive; hence, they are good candidates as catalysts for potential industrial applications. In the experimental setup, a pair of tungsten electrodes, connected by a high-voltage cathode, was submerged in an aqueous solution containing Fe and Ni chlorides. One electrode was the high-voltage cathode, while the other was the grounded anode. Pulsed discharges were generated to produce Fe and Ni compounds. The resulting Fe-Ni nanoparticles (NPs) were characterized by transmission electron microscopy (TEM) to determine their shape, size and composition, which depends on the concentrations of the metal chlorides in the electrolyte solution. Those NPs were then coated on silica tubes inserted in the MW reactor at various positions to establish their influence on the NH3 decomposition and H2 recombination processes. The primary goal of this study is to compare the dissociation of NH3 with and without catalysts, aiming to achieve optimal results for H2 production. This study investigates the impact of experimental parameters on ammonia cracking efficiency within a microwave plasma combined with catalysis. We compare these factors with ruthenium-catalyzed and non-catalyzed thermal processes, recognized as leading methods for ammonia cracking. The goal is to gain insights into the mechanisms of ammonia decomposition in microwave plasmas and evaluate the efficiency of our proposed methodology relative to established thermal processes, contributing to the advancement of sustainable and optimized ammonia cracking practices and decarbonated hydrogen production. Acknowledgements The authors would like to thank the Department of Physics, College of Science, Jazan University, Jazan 45142, Saudi Arabia, for the financial support to M. Awaji and SAKOWIN for the financial support to L. Pentecoste.

Blooming microflowers: Shaping TiO2 nanostructures via anodization in metal chloride-based electrolytes

TiO2 microflowers, consisting of nanotubes, were generated via potentiostatic anodization in fluoride-free electrolytes infused with metal chlorides. Anodizing titanium foil at 15 V for 10 min in electrolytes containing 0.1 M of FeCl3·6H2O, CrCl3·6H2O, FeCl2·4H2O, and CuCl2·2H2O yielded nanotubes with outer diameters of approximately 30 nm, 45 nm, 50 nm, and 60 nm, respectively. The introduction of metal chloride to the electrolyte significantly altered the anodization kinetics, facilitating the growth of TiO2 microflowers. These structures consist of nanotube bundles that are of few microns in length with tunable diameters, achieved rapidly within the anodization timeframe. Microflowers formed in FeCl3·6H2O electrolyte feature high aspect ratio TiO2 nanotube bundles with smaller diameters and higher nucleation density, whereas those developed in CrCl3·6H2O, FeCl2·4H2O, and CuCl2·2H2O electrolytes exhibit less preferable morphology.

Chlorine-Induced Stress Corrosion Cracking of Single Crystal Superalloys at 550 °C

AbstractThis study has investigated the effect of NaCl and different gaseous environments on the stress corrosion cracking susceptibility of CMSX-4 at 550 °C. The presence of SOx leads to the rapid dissociation of NaCl into Na2SO4 and the release Cl2 and HCl, which then trigger an active oxidation mechanism and stress corrosion cracking. The incubation time for crack initiation at 690 MPa and in the presence of a sulphur containing environment is 10 min. A working hypothesis is that stress corrosion cracking occurs due to the hydrogen released at the oxide/alloy interface when metal chlorides are formed; however, this hypothesis needs to be further explored.

Model based analysis of trace metal dosing strategies to improve methane yield in anaerobic digestion systems

Favourable effects of trace metals (TMs) on regulating anaerobic digestion (AD) performance are extensively utilised to improve methane yield. This study discusses a model-based approach to find out the best TM dosing strategies. The model has been applied to compare continuous, preloading, pulse dosing and in-situ loading. Simulations were also carried out to comprehend appropriate dosing form, dosing time and quantity of metals to be dosed. Model results show that the best way to dose TMs is repeated pulse dosing at low concentration levels in the optimum range with high frequency. Best dosing strategy for the system in this study was found to be 5 µM pulse loading at 5 days intervals as it gave maximum methane production and low effluent metal loss. Preferable dosing form depends on reactor configuration and this has been verified after model calibration with experimental data. Easily dissociable metal chlorides are ideal for continuous reactors.

Ultra-Dilute SnCl4-Catalyzed Conversion of Concentrated Glucose to 5-Hydroxymethylfurfural in Aqueous Deep Eutectic Solvent.

5-Hydroxymethylfurfural(HMF) is a versatile chemical synthesized from glucose dehydration catalyzed by metal chloride (MClx) in deep eutectic solvents (DESs). However, the low glucose concentration and high catalyst dosage hinder large-scale HMF production. Herein, we report an aqueous DES of tetraethylammonium bromide(TEAB)-glucose for converting concentrated glucose (40 wt%, relative to TEAB) using ultra-dilute SnCl4 (0.25 mol%), achieving a 62% yield of HMF. Ultra-dilute MClx-catalyzed selective conversion of glucose is feasible only when combining SnCl4 with Br-based DES, which is elucidated by density functional theory and molecular dynamic calculations. Using SnCl4 is essential due to its higher glucose isomerization activity than AlCl3 and CrCl3, which can be attributed to its low-barrier coordination with glucose and its barrier-free separation from fructose. Halide anions in DESs strongly interact with glucose, hindering the MClx-glucose coordination and thereby reducing MClx's activity for glucose isomerization. Consequently, Br-based DESs facilitate higher activity of MClx than Cl-based DESs, due to the weaker interaction between halide anion and glucose. In addition, we elucidated the side reactions including condensation, polymerization, and isomerization, and proposed a reaction network. Our findings clarify the differential activity of MClx and the impact of halide anions in DESs on MClx's activity.

Dual‐Doping Strategy of Metal Chlorides in Ambient Air with High Humidity for Achieving Highly Air‐Stable All‐Inorganic Perovskite Solar Cells

Dual‐Doping Strategy of Metal Chlorides in Ambient Air with High Humidity for Achieving Highly Air‐Stable All‐Inorganic Perovskite Solar Cells

Metal Chloride‐Induced Hydrogen Transfer Enables Efficient Conversion of Aromatic Hydrocarbons for Sodium Storage

AbstractThe cost‐effective synthesis of high‐performance hard carbons (HCs) is a key step of sodium‐ion batteries toward practical applications. Considering the rich resource of low‐value aromatic hydrocarbons (e.g., pitch), there is tremendous interesting in its conversion into value‐added HCs. Unfortunately, it still lacks an efficient way for the synthesis, in addition to the time‐consuming oxygen contamination of the carbon framework. Herein, a universal strategy is reported that enables the efficient synthesis of HCs from pitch by modulating hydrogen transfer using metal chlorides. CuCl2 is selected as the model modulator and the effect of different metal chlorides (FeCl3, AlCl3, ZnCl2, and MgCl2) are further explored. Based on material characterizations and density functional theory calculation employing 1‐methylnaphthalene as the model molecule, it shows that the hydrogen capture and chlorination reactions mediated by CuCl2 and FeCl3 are thermodynamically favored, which promote the crosslinking of pitch to form HCs. After optimization, the derived HC exhibits superior performance of reversible capacity of 304.8 mAh g−1 and a high initial Columbic efficiency of 88.4%. These discoveries provide new insights into the synthesis of HCs from aromatic hydrocarbons, facilitating their utilization in electrochemical energy storage.

Insight into catalytic effects of alkali metal salts addition on bamboo and cellulose pyrolysis

Alkali metal compounds have vital influence on biomass pyrolysis conversion. In this study, cellulose, and bamboo catalytic pyrolysis with different alkali metal salts catalysts (KCl, K2SO4, K2CO3, NaCl, Na2SO4, and Na2CO3) were investigated in the fixed-bed reaction system. The effects of cations (K+ and Na+) and anions (Cl-, SO42−, and CO32-) on the evolution properties of biochar, bio-oil, and gas products were explored under both in-situ and ex-situ catalytic pyrolysis. Results showed that alkali metal salts facilitated the yields of biochar and gases at the expense of that of bio-oil. Alkali metal chloride and sulfate showed a weaker catalytic effect, while alkali metal carbonate greatly promoted the generation of gas products and increased the condensation degree of biochar. With the addition of K2CO3 and Na2CO3, cyclopentanones content was over 50% from cellulose catalytic pyrolysis, and phenols content (mainly alkylphenols) reached over 80% from bamboo catalytic pyrolysis. Moreover, solid-solid catalytic reactions with K2CO3 and Na2CO3 catalysts had an important role in strikingly promoting conversion of pyrolysis products, and the solid-solid and gas-solid catalytic reactions with alkali metal carbonate catalysts were stronger than those with alkali metal chloride and sulfate catalysts. Furthermore, the possible catalytic pyrolysis mechanism of alkali metal salts on biomass pyrolysis was proposed, which is important to the high-value utilization of biomass.

Dynamic Ion Correlations and Ion-Pair Lifetimes in Aqueous Alkali Metal Chloride Electrolytes.

Electrolytes are central to many technological applications, as well as life itself. The behavior and properties of electrolytes are often described in terms of ion pairs, whereby ions associate as either contact ion pairs (in which ions are "touching") solvent-separated ion pairs (in which ions' solvent shells overlap) or solvent-solvent-separated ion pairs (in which ions' solvent shells are distinct). However, this paradigm is generally restricted to statistically averaged descriptions of solution structure and ignores temporal behavior. Here we elucidate the time-resolved dynamics of these ion-ion interactions in aqueous metal chloride electrolytes using the partial van Hove correlation function, based on polarizable molecular dynamics simulations. Our results show that the existence and persistence of ion pairs in aqueous metal chloride electrolytes should not be assumed a priori, but in fact are ion specific features of the solution with lifetimes on subpicosecond time scales.

Computational Study of Molecular Interactions in ZnCl2(urea)2 Crystals as Precursors for Deep Eutectic Solvents

Deep eutectic solvents (DESs) are now enjoying an increased scientific interest due to their interesting properties and growing range of possible applications. Computational methods are at the forefront of deciphering their structure and dynamics. Type IV DESs, composed of metal chloride and a hydrogen bond donor, are among the less studied systems when it comes to their understanding at a molecular level. An important example of such systems is the zinc chloride–urea DES, already used in chemical synthesis, among others. In this paper, the ZnCl2(urea)2 crystal is studied from the point of view of its structure, infrared spectrum, and intermolecular interactions using periodic density functional theory and non-covalent interactions analysis. The two main structural motifs found in the crystal are a strongly hydrogen-bonded urea dimer assisted by chloride anions and a tetrahedral Zn(II) coordination complex. The crystal is composed of two interlocking parallel planes connected via the zinc cations. The infrared spectrum and bond lengths suggest a partially covalent character of the Zn−Cl bonds. The present analysis has far-reaching implications for the liquid ZnCl2–urea DES, explaining its fluidity, expected microstructure, and low conductivity, among others.

Task-specific design of protic metal-based deep eutectic solvents for efficient separation of HCl/SO2

Efficient separation and recovery of hydrogen chloride (HCl) from HCl tail gas containing impurities such as sulfur dioxide (SO2) is very important from the viewpoint of economy and environment. However, due to the similar dissolution ability of SO2 and HCl, most solvents, including organic solvents, ionic liquids and deep eutectic solvents (DESs), show low SO2/HCl selectivity near 1.0 and are thus incompetent to separate SO2/HCl. To address this, we firstly reported the task-specific design of a novel class of protic metal-based DESs (PM-DESs) containing hydrochloride, metal chloride and sulfolane, which have good SO2 affinity but much inhibited HCl uptake, for the separation of HCl/SO2. The solubility data of SO2 and HCl in PM-DESs were determined and correlated by Krichevsky-Пiinskaya (K-I) equation. Among these PM-DESs, N,N-dimethylaniline hydrochloride (DMA·HCl) + zinc chloride (ZnCl2) + sulfolane exhibits satisfactory recyclability and selectivity up to 2.669 (100 kPa, 313.2 K), which is the highest value reported so far. Absorption of HCl/SO2 (50/50) mixed gas was also tested, with a high SO2/HCl selectivity of 3.250 obtained. In addition, the NMR and FTIR spectroscopic characterizations paired with quantum chemistry calculation were utilized to investigate the absorption mechanism from the perspective of atomic level. The DESs developed in the present work have the potential to separate and recycle HCl from SO2 owing to their good selectivity and desirable reversibility, and the strategy proposed in this work may offer new guidance for designing green media for HCl recovery.

Fabrication and Identification of Characteristics and Biological Evaluation of 2-[(4-hydroxy-phenylimino)-methyl]4-methoxy-phenol (4-MSAP-L) and its First Transition Metal Complexes Derived from 5-methoxysalicylaldehyde and 4-aminophenol

Abstract The demand for novel and more effective anti-microbial agents is a continuous occurrence since the microbes has the ability to develop immunity to the existing antibiotics. Combination, characteristics of novel 2-[(4-Hydroxy-phenylimino)-methyl]-4-methoxy-phenol (4-MSAP-L) and its corresponding metal complexes and their biological applications are widely discussed in this paper mixture of 4-MSAP-L from 5-methoxysalicylaldehyde with p-aminophenol is done which has not been earlier on announced. Starting from this 4-MSAP-L, different transition metal complexes were prepared. Here, Mn(II), Ni(II), Co(II), Cu(II) and Zn(II) metal chlorides used in the coordination. With the assistance of analytical as well as physico-chemical arrangements 4-MSAP-L and metal complexes prepared and characterized. Biological studies of the newly synthesized 4-MSAP-L and metal complexes also reported.

Optimization of Conditions for the Determination of Low Concentrations of Chlorate Ions in Alkali Metal Chloride Solutions by Capillary Electrophoresis

Optimization of Conditions for the Determination of Low Concentrations of Chlorate Ions in Alkali Metal Chloride Solutions by Capillary Electrophoresis

Effects of metal chloride on promoting the emission efficiency and stability of 2D CsPb2(ClBr)5 perovskite nanocrystals and their application

Effects of metal chloride on promoting the emission efficiency and stability of 2D CsPb2(ClBr)5 perovskite nanocrystals and their application

Thermodynamic Analysis of Chloride Corrosion in Steel for Energy System Applications in Fe-O-Cl-Na Environments

The assumptions of contemporary energy policies are increasing the share of renewable energy sources. Biomass combustion is developing as an alternative to fossil fuels. However, it faces challenges such as limited corrosion resistance of steel boiler components due to chloride compounds in flue gases and fly ash. This paper provides a comprehensive thermodynamic analysis of chloride-induced corrosion in steel in the Fe-O-Cl-Na environment, focusing on the influence of steam concentration in the gas phase. The study was performed by using the general thermodynamic rules, the thermodynamic properties of the pure components involved in the reaction, and the properties of the solutions formed in the liquid and gas phases. The study also examined the impact of alkali metal chlorides, particularly NaCl, on the formation of NaFeO2 in the passive oxide scale layer Fe3O4/Fe2O3. Furthermore, it investigated the condensation of NaCl vapour formation of low-melting eutectic mixtures in deposits and the resulting consequences on the corrosion process. The role of HCl in the chlorination and oxidation process of steel in melted ash deposits was also discussed. The presented thermodynamic analysis was compared with assumptions of an “active oxidation” model. This study can be a valuable resource for experimental research planning and a guide for preventing corrosion in industrial settings.