Zn Chloride Research Articles

Experimental analysis on the effects of trace metals as micronutrients in enhancing biomethane production

Anaerobic digestion (AD) of microbial biomass has proven to be a significant breakthrough technique in producing biogas rich in methane. The quantity of biogas obtained by anaerobic digestion processes varies significantly based on the nature and characteristics of the substrates used. This research work focuses on the use of trace metals such as Fe, Cu, Zn, Mn, Mg, Ni in proper proportions to enhance the microbial consortium thus aiding in the production of biogas of desired quality. The substrate used for this study is Food Waste and Cow dung. Food waste from the college canteen was used as the substrate and cow dung was used as an inoculum for providing a catalytic effect in the anaerobic reactor. Food waste and cow dung in the ratio 75:25 was fed into the anaerobic digesters with varying concentrations of micronutrients supplemented to the reactors operating at a pH range maintained between 6.8 and 7.2 under room temperatures (22–27 ºC). The effect of these micronutrients on the anaerobic digestion process was observed by analysing the biogas yield, pH, alkalinity, total solids, and volatile solids of the samples. Sulphates of Fe, Cu, Mn, Ni and Chlorides of Zn and Mg was used in this study. Fe, Cu, Zn, Mn, Mg, Ni were fed to the anaerobic reactor at varying concentrations to arrive at the optimum dosage for the chosen substrates. The optimum dosage for the chosen substrate concentration was taken as that concentration which yielded maximum biogas yield with less retention time. Fe at concentrations varying from 1 mg/l–5 mg/l was fed to the anaerobic reactor and the optimum dosage for the chosen substrate concentration was noted at 1 mg/l. The reactor with an Fe concentration of 1 mg/l showed an increase in biogas production rate of about 68% compared to the sample without Fe supplementation as well as the ones with other dosages greater than 1 mg/l and less than 1 mg/l of Fe dosage. Each nutrient is subjected to an individual dosage analysis before arriving at the optimum dosage and then a mixture of the arrived optimum dosages will be analysed for further study. The process set-up will be conducted for a minimum retention period of 20 days and terminated when the results show a deep fall in the biogas production for consecutive days. Biogas produced for the nutrient supplementation of 1 mg/l of Fe, 0.5 mg/l of Cu, 1 mg/l of Zn, 0.5 mg/l of Mn, 1 mg/l of Mg and 0.5 mg/l of Ni yielded a biogas of 850 ml/g VS in 10 day retention time. Triplicate samples study were conducted and biogas yield measured daily to arrive at concordant results. The results showed an increase in the biomethane yields of the substrate by about 60% compared to the reactors which had no micronutrient supplementations. Furthermore, the study summarized that not all micronutrients are essential for a successful microbial metabolism to take place in an anaerobic digester as the micronutrient Manganese at varying dosages of 0.5 mg/l, 1 mg/l and 1.5 mg/l showed an antagonistic effect on the microbial activity in the reactor. The results obtained from this study showed a significant improvement in the quantity of biogas produced from the substrates supplemented with micronutrients at optimum dosages thus arriving at an efficient and effective method for treating waste in a sustainable way.

Chlorination for all solid-state zinc-graphite battery: Investigate into the charge-discharge mechanism of zinc electrodes and sodium silicate electrolyte

Zn solid-state batteries offer a novel and environmentally friendly energy storage solution with excellent safety features. This study explores the material characteristics and electrochemical mechanisms of the Zn anode and sodium silicate solid electrolyte powder after HCl chlorination. Results reveal the formation of Zn chloride hydroxide monohydrate (Zn5OH8Cl2⋅H2O, known as Simonkolleite) in the zinc anode post HCl treatment. The compound's layered structure enhances ion transport. The sodium silicate electrolyte exhibits increased surface area after HCl treatment. In engineering applications, a solid-state battery assembled with Simonkolleite anode, electrolyte (HB), and graphite film (GF) cathode demonstrates a high capacity (>5000 mAh/g) in the first discharging cycle and impressive stability over 30–100 cycles, highlighting its promising potential for energy storage.

Brønsted-Lowry Acid-Based Aqueous Eutectic Electrolyte for Practical Zinc Batteries.

Aqueous highly concentrated electrolytes (AHCEs) have recently emerged as an innovative strategy to enhance the cycling stability of aqueous Zinc (Zn) batteries (AZB). Particularly, thanks to high Zn Chloride (ZnCl2) solubility in water, AHCEs based on ZnCl2 feature remarkable Zn anode stability. However, due to their inherently acidic pH and Cl- anion reactivity, these electrolytes face compatibility challenges with other battery components. Here, an aqueous eutectic electrolyte (AEE) based on Brønsted-Lowry concept is reported-allowing the usage of cheap and abundant salts, ZnCl2, and sodium acetate (NaAc). The reported, pH buffered, AEE displays a higher coordination of water at an even lower salt concentration, by simply balancing the acceptor-donor H─bonding. This results in impressive improvement of electrolyte properties such as high electrochemical stability, high transport properties and low glass transition temperature. The developed AEE displays higher compatibility with vanadium oxide-based cathode with a 50% increase in capacity retention in comparison to sat. ZnCl2. More importantly, the pH buffered AEE solves the incompatibility issues of ZnCl2 toward commonly used aluminium (Al) current collector as well as cellulose separator. This work presents an efficient, simple, and low-cost strategy for the development of aqueous electrolytes for the practical application of Zn batteries.

New insights on the formation of the Jingchong Cu-Co-Pb-Zn deposit, South China: Evidence from sphalerite mineralogy and muscovite 40Ar-39Ar dating

The northeastern Hunan Province hosts numerous hydrothermal Pb-Zn(-Cu-Co) polymetallic deposits. As a representative example, the Jingchong Cu-Co-Pb-Zn deposit is characterized by the lower Cu-Co and upper Pb-Zn mineralization, whereas little is known about Pb-Zn mineralization. In this study, three generations of sphalerite were identified based on their textural and geochemical differences. The Sph-I exhibits the oscillatory zoning that consists of reddish-brown Sph-Ia (poor in chalcopyrite inclusion) alternating with dark Sph-Ib with zoned chalcopyrite inclusion. Sph-II is composed of honey-brown Sph-IIa (abundant chalcopyrite droplets) and white clean Sph-IIb (rare chalcopyrite inclusion). The black Sph-III is characterized by nano- to submicron-sized chalcopyrite inclusions with typical “dusting” or “watermelon” texture and crosscuts all other sphalerite generations in veinlets. The electron microprobe and laser ablation inductively coupled plasma mass spectrometry show that Sph-I has higher Fe and Mn contents, but lower Cd, Cu and Ag contents than Sph-II and Sph-III. Sphalerite geothermometry yields temperatures of 334–346 (±58)°C for Sph-I, 254–289 (±60)°C for Sph-II and 286 (±55) °C for Sph-III. The sulfur fugacity ranges from logfS2 values of −9.03 to −8.26 for Sph-I to −11.77 to −10.63 for Sph-II and −10.82 for Sph-III. The combined textural features and chemical compositions indicate that the self-organized mechanism forms Sph-I, and that the coupled dissolution and precipitation reactions triggered by the influx of Cu-elevated fluids are responsible for the formation of Sph-II and Sph-III. The associated pyrite and pyrrhotite inclusions in sphalerite are produced by the exsolution mechanism, while chalcopyrite inclusions are formed by co-precipitation due to local supersaturation at the interface of sphalerite with fluid. The 40Ar-39Ar dating of muscovite in the Jingchong deposit yields a mineralizing age of ca. 121.1 ± 2 Ma, consistent with the ca. 130–120 Ma Pb-Zn mineralizing events in the northeastern Hunan Province. The sulfur isotopic values (−3.0 to +3.5‰) of the Pb-Zn ores are similar to that of Cu-Co ores, indicating a magmatic sulfur origin. Together with the trace element affinity of sphalerite with magmatic-hydrothermal origin, it was proposed that the Jingchong Pb-Zn and Cu-Co mineralization were formed in the same magmatic-hydrothermal system. The placement of Pb-Zn orebodies at the upward zoning of Cu-Co orebodies could be attributed to the higher solubilities of Pb and Zn chloride complexes in hydrothermal fluids, relative to Cu chloride complex.

Synthesis and Characterization of Pyridine Acetohydrazide Derivative for Antimicrobial Cotton Fabric

An increase in textile resistance to antimicrobial agents has posed a pressing need for the development of new antimicrobials. Therefore, the antimicrobial characteristics of thiophene and pyridine acetohydrazide derivatives have been developed as novel textile-modified complexes exhibiting antibacterial agents. Synthesis and characterization of pyridyl-thienyl acetohydrazide derivative (AHZ) using NMR (13C and 1H) and FTIR. Modification of cotton fabric (CF) with acetohydrazide (AHZ) and metal chlorides of divalent Cr, Mn, Co, Ni, Cu, and Zn and trivalent Fe, and Cr. SEM-EDX and Fourier-transform infrared were utilized to characterize cellulose-based cotton fabric (CF) attached to AHZ and their metal (M) complexes. Antimicrobial activity was examined against two types of bacteria, namely S. aureus and E. coli, and two types of fungi, namely C. albicans and A. flavus. All modified samples exhibited higher efficiency towards bacterial strains than fungal strains. In addition, cellulose modified with Ni (II) confers the most antibacterial protection efficiency.

New dimeric complexes with semicarbazone mannich-based ligand; formation, structural investigation and biological activity

The formation of a new semicarbazone Schiff-base ligand (E)-2-(2-(phenyl(2-phenylhydrazinyl)- methyl)cyclohexylidene)hydrazine-1-carboxamide (HL) and its complexes are reported. The new ligand was prepared from the condensation of the Mannich-base 2-(phenyl(2-phenylhydrazinyl)methyl)cyclohexan-1-one (M) with the semicarbazide. A series of metal complexes were prepared by the reaction of the ligand with the metal chlorides of Cr(III), Mn(II), Co(II), Ni(II), Cu(II)), Zn(II) and Cd(II). The structure of the ligand and its complexes were elucidated through analytical and spectroscopic techniques. The analyses indicated the ligand behaves as a monobasic tridentate species and the isolation of dimeric complexes with the general formula; [Cr(L)(Cl)2(H2O)]2, [M(L)Cl]2 (where M= Mn(II), Co(II), Ni(II), Cu(II)), Zn(II) and Cd(II)). These studies revealed a distorted octahedral geometry for Cr(III), a distorted square planar for Cu(II) and a tetrahedral arrangement for Mn(II), Co(II), Ni(II), Zn(II) and Cd(II). The biological activity of the prepared compounds against Escherichia coli, Pseudomonas auroginosa, Staphylococcus aureus and Bacillus subtilis compared with Cefotaxime (as a standard antibiotic) was also explored. Some of the examined compounds indicated a similar antibacterial activity to Cefotaxime. Furthermore, antifungal activity against Candida albicans and Rhizopus sporium was investigated, which showed that the ligand and its complexes exhibited good antifungal activity. Keywords: Schiff-base ligand; Structural characterization; Dimeric semicarbazone complexes; Biological activity.

Zinc Status of Horses and Ponies: Relevance of Health, Horse Type, Sex, Age, and Test Material

Little is known about the animal- and diet-related factors that could interfere with the plasma zinc (Zn) concentrations of equines. Additionally, the adequacy of plasma to reflect changes in the Zn intake is unclear. In the first part of this study, the plasma Zn concentrations of hospitalized horses and ponies (n = 538) were measured and evaluated for the impact of the age, sex, horse type, and internal diseases of the animals. In the second part, the effects of increasing dietary Zn chloride hydroxide and Zn methionine supplementations were assessed on the plasma and mane hair Zn concentrations of healthy horses (n = 2) and ponies (n = 8). Part 1: The age, sex, and horse type did not influence the plasma Zn concentrations. No effect of internal diseases was observed, with the exception of higher plasma Zn concentrations in animals with metabolic disorders compared to the control group (p < 0.05). Part 2: Both Zn supplements dose-dependently increased the Zn concentrations in the mane hair (p = 0.003), but not in the plasma of the horses and ponies. In conclusion, the plasma Zn concentrations were widely unaffected by nutritional and non-nutritional factors in equines, while mane hair samples better reflected the dietary Zn supply.

The Co-catalyst Effects of Mn(II), Zn(II), and Cr(III) Chlorides on Acidic Ionic Liquid Catalyzed Synthesis of Value-added Products from Cellulose in Aqueous Ethanol

Background: Catalytic depolymerization and processing of cellulose can be used to produce value-added renewable feedstock chemicals. Objective: This study aimed to develop an acidic ionic liquid-metal ion chloride catalyst system-based single-reactor method for processing cellulose into value-added products. Methods: The effect of metal chlorides as co-catalysts on 1-(1-propylsulfonic)-3-methylimidazolium chloride acidic ionic liquid catalyzed degradation of cellulose in 40% (v/v) aq. ethanol was studied by measuring levulinic acid, ethyl levulinate, and 5-hydroxymethylfurfural yields. Results: In experiments with Mn(II) and Zn(II) chloride co-catalysts at 160 and 170°C for 12 h, the initial yields of ethyl levulinate and 5-hydroxymethylfurfural improved from ~ 7% to ~ 12-15% due to co-catalytic effects. The highest enhancements in ethyl levulinate yields were observed with CrCl3, where the yield increased from 6 to 27% with the addition of a 10 mol% co-catalyst. Conclusion: All three transition metal chlorides studied caused improvements in yields of secondary products, ethyl levulinate and 5-hydroxymethylfurfural, in acidic ionic liquid catalyzed degradation of cellulose in aqueous ethanol. The most significant enhancements in ethyl levulinate yields were observed with CrCl3 as a co-catalyst.

光沢剤を含むアルカリジンケート浴から電析したZn-Ni合金皮膜の耐食性

Zn–Ni alloys were electroplated on an Fe plate with thicknesses of 40 μm at 500 A·m−2 and 293 K in unagitated zincate solutions. The reaction product of epichlorohydrin and imidazole (IME) was added in the solution as a brightener at the concentration of 0-5 ml/dm−3. The corrosion resistance of the obtained Zn–Ni alloys films was investigated from the polarization curve in 3 mass% NaCl solution before and after the corrosion treatment (formation of corrosion products) in NaCl solution for 48 h. Before the corrosion treatment, the corrosion current density of plated films rarely changed regardless of addition of IME into the zincate solution because the reduction reaction of dissolved oxygen rarely changed. However, in films plated from the solution containing IME, the anode reaction was suppressed and the corrosion potential shifted to noble direction. The suppression of anode reaction with an addition of IME in plating solution is attributed to the increase in γ-phase in plated films. On the other hand, after the corrosion treatment, the morphology of Zn chloride hydroxide of corrosion product was uniformly formed on the surface with increasing the concentration of IME. The reduction reaction of dissolved oxygen was suppressed with increasing the concentration of IME, resulting in decrease in corrosion current density.

Speciation and isotopic analysis of zinc in size-fractionated aerosol samples related to its source and chemical processes

Zinc (Zn) in aerosols plays important roles for biological activity and attracts public attention from the perspective of environmental measures. Because of its high volatility and water solubility, Zn is readily released into the atmosphere by human activities and supplied to natural water. To explore the origin and formation process of Zn in atmospheric aerosols, it is important to investigate isotopic (= δ66Zn) and speciation information of Zn in size-fractioned aerosols. We measured light δ66Zn (e.g., δ66ZnIRMM = −1.32‰ as the lowest value; IRMM-3702 is used for the normalization in this study) mainly for the particles ranging from 0.65 to 4.7 μm for the samples collected at Tsukuba, Chiba, and a motorway tunnel (Yasumiyama Tunnel in Hiroshima) in particular for the samples collected in 2002, but δ66ZnIRMM in the particle sizes increased above −0.8‰ for the samples collected in 2011 and 2016. Zn species in aerosols were estimated based on X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy, suggesting that (i) Zn oxalate and sulfate and (ii) Zn oxide, sulfide, and carbonate are main Zn species in fine and coarse particles, respectively. In particular, Zn chloride was found mainly in the middle particle size range (2.1–4.7 μm), which corresponds to the range with light δ66Zn, suggesting that the light δ66Zn was caused by emission of Zn chloride during artificial combustion processes in accordance with other studies. The origins of Zn in aerosols are assumed to have three endmembers; (A) tire and brake wears and road dust, (B) industrial emissions, and (C) vehicular exhaust. Their formation mechanisms are related to vaporization and mixing processes based on the results of combined analysis of atmospheric concentration, speciation, and isotopic composition of Zn with different particle sizes. These trends could be successfully interpreted by species-specific δ66Zn values: component (A) consisting mainly of Zn oxide and sulfide with relatively heavier δ66Zn, component (B) Zn chloride and sulfate secondarily formed in the droplet mode having lightest δ66Zn among all the species, and (C) Zn oxalate with δ66Zn closer to 0‰ due to its emission by the complete combustion in vehicle engines. Species-specific Zn isotope data obtained by the simultaneous application of speciation and isotopic analyses of Zn in size-fractionated aerosols complementary provide novel information on the initial generation and secondary processes for the formation of Zn species in the aerosols.

Zinc Chloride Enhances the Antioxidant Status, Improving the Functional and Structural Organic Disturbances in Streptozotocin-Induced Diabetes in Rats.

Background and Objectives: Diabetes mellitus (DM) is a complex disease affecting the whole metabolic balance of the body and resulting in multiple organ complications: cardiovascular, neuronal, renal, etc. Our study focuses on investigating the effect of zinc chloride (Zn) on certain blood parameters suggestive for assessing the metabolic disturbances, the liver and kidney function, the oxidative stress and the immune defense capacity in experimental-induced DM with streptozotocin (STZ) and cholesterol in rats. Materials and Methods: The animals were assigned to three groups, as follows: Group 1 (Control): buffer citrate solution 0.1 mL/100 g body; Group 2 (STZ): 20 mg/kg body STZ and fat diet (10 g cholesterol/100 g diet); Group 3 (STZ+Zn): 20 mg/kg body STZ + 5 mg/kg body Zn chloride and the same fat diet. DM was induced by administering STZ in a single take daily, for three consecutive days, Zn and citrate buffer were administered orally for a month. The protocol was approved by the Ethics Committee of the University 'Grigore T Popa' Iasi, in agreement with the International Regulations about the handling of laboratory animals. Results: The use of STZ in rats fed with cholesterol was correlated with important weight gain, hyperglycemia, the intensification of the transaminases activity and the increase in serum alkaline phosphatase, cholesterol, triglyceride, urea, creatinine and in malondialdehyde. Conclusions: The treatment with Zn resulted in weight loss and a decrease in blood sugar in diabetic rats. Supplementation with Zn notably reduced oxidative stress, preserved the pancreatic architecture and restored the liver and kidney function and structure in STZ-induced DM in rats.

Synthesis, characterization, and biological application of some transition metal complexes of N'-(benzo[d][1,3]dioxol-5-ylmethylene)isonicotinohydrazide

Various spectrum techniques were used to analyze the newly synthesized Schiff's base derivative, N'-(benzo[d][1,3]dioxol-5-ylmethylene)isonicotinohydrazide. The reaction with Cu(II), Co(II), Ni(II) and Zn(II) chloride produced complexes of 1:1 (M:L) stoichiometry. The spectral data, FTIR and NMR, disclosed that the INP chelated the central metal in neutral bidentate manner via the carbonyl oxygen and azomethine nitrogen atoms. The octahedral configuration of the complexes has been elucidated by electronic, magnetic, and ESR measurements. The powder XRD patterns of metal complexes designated that Cu(II) has a monoclinic crystal system, whereas Co(II) and Zn(II) have orthorhombic crystal systems and Ni(II) has a triclinic crystal system. The DFT quantum chemical simulation validated the suggested structures and was used to calculate HOMO-LUMO energies. Furthermore, the NLO properties, polarizability, and hyperpolarizability of the INP and metal complexes were calculated, indicating that metal chelation improved the than the ligand. The isolated compounds biological activity, antioxidant and antitumor, were explored and results disclosed that the metal complexes exhibited enhanced activity than ligand.

An experimental and thermodynamic study of sphalerite solubility in chloride-bearing fluids at 300–450 °C, 500 bar: implications for zinc transport in seafloor hydrothermal systems

The solubility and speciation of zinc (Zn) in chloride-bearing aqueous fluids at high temperature and pressure are important for understanding Zn transport in natural hydrothermal systems and associated mineralizing processes. Here, we measured sphalerite solubility in NaCl-HCl-H2O fluids using a fixed-volume titanium alloy hydrothermal reactor equipped with a newly designed gas-tight titanium piston sampler. This novel reactor-sampling system is capable of acquiring internally filtered fluids at high temperature and pressure. The experiments were conducted at 300–450 °C, 500 bar, in fluid with 0.5 m and 1 m NaCl, respectively. The measured sphalerite solubilities are consistent with predicted values using previous thermodynamic data at 300–400 °C, but diverge significantly above 400 °C. To resolve this discrepancy, we adjusted the solubility product of Zn minerals by modifying the heat capacity and Born coefficients that describe the Gibbs Free Energy of formation from the elements of the Zn2+ aqua ion based on the new solubility data. The refined Helgeson-Kirkham-Flowers (HKF) equation of state (EoS) of Zn2+ empirically reproduces the solubility data of Zn minerals from previous experimental studies well over the covered T-P range (25–600 °C, Psat to 2 kbar), but extends accurate predictions to conditions typical of deep sea hydrothermal systems, down to fluid densities of 0.35 g/cm3. Thermodynamic modelling using the revised EoS of Zn2+ shows that higher temperatures, chlorinity and lower pH increase Zn solubility, and that Zn chloride complexes are the predominant species. The influence from salinity on Zn solubility is less significant in fluids with low pH. Applied to seafloor hydrothermal systems, our results suggest that in addition to temperature, pH and total dissolved chloride, fluid/rock ratio may be an important factor contributing to Zn concentrations in vent fluids at Mid Ocean Ridges.

Determination of the activation parameters for the ring-opening polymerization of ε-caprolactone initiated by Sn(II) and Zn(II) chlorides using the fast technique of DSC

The kinetics of the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by 1.0 mol% of tin(II) chloride (SnCl2) and zinc(II) chloride (ZnCl2) was completely investigated by the differential scanning calorimetry (DSC) technique. The fast method to determine the activation parameters such as activation enthalpy (∆H≠) and activation entropy (∆S≠) was successfully developed basing on the transition state theory and isoconversional method. From Friedman isoconversional method, the values of activation energy (Ea) for the ROP of ε-CL initiated by SnCl2 (36.2 ± 1.5 to 40.8 ± 1.5 kJ/mol) were lower than ZnCl2 (51.9 ± 2.8 to 62.3 ± 2.8 kJ/mol). From Starink isoconversional method, the Ea values for the ROP of ε-CL initiated by SnCl2 (32.3 ± 1.1 to 35.8 ± 1.1 kJ/mol) were also lower than ZnCl2 (59.2 ± 0.8 to 62.1 ± 0.8 kJ/mol). By using the compensation parameters, the reconstructed monomer conversion function (f(α)) was fitted with the Avrami-Erofeev nucleation model (A2, f(α) = 2(1-α)[-ln(1-α)]1/2). The values of frequency factor (A) for the ROP of ε-CL with SnCl2 and ZnCl2 were 4.3 × 103to 1.6 × 104 min−1 and 2.1 × 105 to 5.3 × 105 min−1, respectively. From the developed rate equation, the values of ∆H≠ and ∆S≠ could be conveniently determined from dynamic heating. The obtained ∆H≠ values for the ROP of ε-CL initiated by SnCl2 and ZnCl2 were similar to the Ea values. The ∆S≠ values for the transition state of the ROP of ε-CL initiated by SnCl2 (-152.0 to -161.7 J/mol.K) were lower than ZnCl2 (-129.6 to -153.1 J/mol.K). The kinetics and the stability of transition state information demonstrated that the reactivity of SnCl2 in the ROP of ε-CL was higher than ZnCl2. The mechanism of the ROP of ε-CL with SnCl2 and ZnCl2 was proposed through a classical coordination-insertion mechanism. From poly(ε-caprolactone) (PCL) synthesis via solvent-free polymerization, SnCl2 acted as the highly effective initiator than ZnCl2. The highest number average molecular weight (Mn) of PCLs obtained from the SnCl2 and ZnCl2 initiator were 1.8 × 105 g/mol and 3.6 × 104 g/mol, respectively. The effectiveness of the slow ZnCl2 initiator in the production of high molecular weight and %yield of PCL could be improved by increasing the synthesis temperature. These SnCl2 and ZnCl2 compounds acted as a powerful initiator for the synthesis of PCL. The obtained results from this work were useful for understanding the transition state formulation in the ROP of other cyclic esters with various initiating systems that still in our attention and would be described in our future work.

Synthesis, characterization, molecular docking and antibacterial activities of Bis-[(E)-3{2-(1-4-chlorophenyl) ethylidiene}hydrazinyl]-N-(4-methylphenyl)-3-oxopropanamideZinc (II) complex

The title Zn (II) complex was synthesized by reacting the compound Bis-[(E)-3{2-(1-4-chlorophenyl) ethylidiene}hydrazinyl]-N-(4-methylphenyl)-3-oxo propanamide with Zn (II) chloride dihydrate in alkaline dimethylsulphoxide and ethanol solution under reflexing condition for 8 h. The resultant compound was filtered and recrystallized from ethanol. The hydrazone Schiff base ligand and its Zn (II) complex were characterized by using UV-Vis spectroscopy and XRD, TEM and SEM analysis. The antibacterial activities of ligand and its Zn complex were examined using disc diffusion method. The spectra results showed that the hydrazone ligand undergoes keto-enoltautomerism forming a bidentated ligand (N,N) towards Zn+2 (II) ion. It is very interesting that on sides of the two hydrazone ligands which coordinate to the Zn+2 ions, an additional two thiosemicarbazine moiety were also coordinated with Zn+2 ions in the crystalline powder, resulting in a hexa coordinated octahedral Zn (II) complex. Both hydrazone Schiff base ligand and its Zn (II) complex were found to exhibit good antibacterial activity even when the concentrations were high. Molecular docking analysis also deciphered that Zinc complex and carbohydrazone ligand both were found to be fitted into the active sites of molecular targets and Zn complex showed better binding affinities towards macromolecules compared to ligand.

Cover Feature: Study on the Isotope fractionation of Zinc in Complexation with Macrocyclic Polyethers (Z. Anorg. Allg. Chem. 6/2021)

The isotope fractionation of Zn was studied by liquid-liquid extraction with aqueous phase of ZnCl2/ HCl and organic phase of crown ethers(CEs), benzo15-crown-5(B15C5), benzo-18-crown-6(B18C6) and Dicyclohexano-24-crown-8(DC24C8)/1,2-dichloroethane. The isotope enrichment factor of the isotope pair 66Zn-64Zn was found to be ϵ66=−0.24 to −0.52‰ in the order of B15C5≥B18C6>DC24C8. The magnitude of ϵ66 was well explained by using the isotope fractionation factors obtained by density functional theory method for Zn chlorides and ZnCl2/CE model molecules. More details can be found in the Article by Toshiyuki Fujii, Chizu Kato, Brandon Mahan, and Frédéric Moynier.

Heavy Metal Extractions from NaCl Brines to Pseudoprotic Ionic Liquids

In liquid–liquid extractions, the aqueous phase from which heavy metal ions are extracted often contains a mixture of salt ions (brine). These additional salt ions may have an effect on the efficiency and selectivity of the extraction of a specific heavy metal ion and may cause a shift in extraction mechanism when the organic phase is an ionic liquid. This has been demonstrated in this study for the extraction of Co, Ni, or Zn chloride by three pseudoprotic ionic liquids (PPILs) in the absence or presence of NaCl up to 4 times the concentration in seawater. In most cases, the extraction efficiency was increased by the presence of NaCl. This increase resulted from a shift in equilibrium referred to as the van’t Hoff–le Chatelier effect. In all cases, also, sodium ions were extracted, but at low efficiencies. An increase in NaCl presence in the brine leads to a slightly higher sodium extraction efficiency, which can also be contributed to the van’t Hoff–le Chatelier effect. Zn ions were transferred to the PPILs by neutral extraction, but only without NaCl in the brine. In all other cases, the transfer of the metal ions occurred with increasing anion exchange between the chloride ions and the trihexylammonium octanoate and trioctylammonium benzoate anions if more NaCl was present. In the case of extraction of Co or Ni ions with trioctylammonium salicylate, a shift in mechanism from anion into cation exchange was observed with a change in NaCl concentration.

Chromium and Zinc Speciation in Airborne Particulate Matter Collected in Ulaanbaatar, Mongolia, by X-Ray Absorption Near-edge Structure Spectroscopy

ABSTRACT This study examined the chemical speciation of atmospheric particulate matter (PM) samples collected in Ulaanbaatar, Mongolia. The health effects of atmospheric aerosol depend on the particles’ size distribution, elemental composition and chemical species as well as other factors, which vary according to the pollution sources and meteorological conditions. Employing the International Atomic Energy Agency (IAEA) supported X-ray fluorescence (XRF) beamline at Elettra Sincrotrone Trieste, Italy, we used a small incidence angle for the synchrotron emission radiation in this ultra-high-vacuum environment to analyze the fine and the coarse mode (PM2.5 and PM2.5-10, respectively) through X-ray absorption near-edge structure (XANES) spectroscopy, which was applied to the K-edges of the chromium (Cr) and zinc (Zn) in PM samples selected via energy-dispersive XRF (EDXRF) analysis for their high concentrations of these transition metals. The spectroscopic results identified trivalent chromium sulfate [Cr2(SO4)3] and chromium oxide (Cr2O3) compounds as the major chemical forms of Cr in both the coarse and the fine PM fraction. Furthermore, both fractions contained abundances of sulfate (ZnSO4) and silicate (Zn2SiO4) compounds, but only the fine mode contained Zn oxalate (ZnC2O4), whereas only the coarse mode contained Zn chloride (ZnCl2). These Cr and Zn species seemed to originate from local anthropogenic sources, e.g., combustion products or traffic-related resuspended road dust. Our findings, which are based on the first chemical speciation analysis from Ulaanbaatar, provide insight into the physiochemical characteristics of atmospheric aerosols as well as information on the potential sources of Cr and Zn species bound to fine and coarse PM.

Kinetics and Mechanisms of Metal Chlorides Catalysis for Coal Char Gasification with CO2

The gasification experiments of coal chars with CO2 were carried out isothermally, with K, Ca, Ni, and Zn chloride catalysts, adopting a thermal gravimetric analyzer (TGA) from 800 to 1100 °C. The kinetic characteristic of the samples were described using the volumetric model (VM), the grain model (GM), and the random pore model (PRM). The morphology patterns of the samples were tested applying X-ray diffraction (XRD) and the catalytic mechanisms concerning the phase changes were proposed. The results confirm that the gasification rate and char reactivities are enhanced by K, Ca and Ni chlorides, while ZnCl2 inhibited the process. The catalysis ability shows the following cation order: Ca &gt; K &gt; Ni &gt; Zn. Among the models described above, PRM was proven to give the best fitting value and hence adopted to kinetics parameters calculation. The activation energies in promoting conditions were lower than that of the uncatalyzed cases. In view of the catalytic mechanism, the K metals tend to form intermediate complexes and repeatedly connect with coal char, while the Ca species may follow the oxidation-reduction mechanism and the Ni metals catalyze the gasification process.

Luminescent Complexes of Co(II), Ni(II), Cu(II), Zn(II)and Bi(III) with 2-Aminothiazole based Ligand and their Biological Studies

3-(thiazol-2-yl carbamoyl) propanoic acid was synthesized by the reaction of 2-aminothiazole and succinic anhydride, which was employed as ligand (LH) for further reaction with Co(II), Ni(II), Cu(II), Zn(II) and Bi(III) chlorides at ambient conditions to afford respective metal complexes, denoted as Co-L2, Ni-L2, Cu-L2, Zn-L2 and Bi-L3. Both the ligand LH and metal complexes were characterized by techniques FT-IR, 1H-NMR, 13C-NMR, powder XRD, TGA and conductometry. FT-IR and NMR studies revealed that ligand (LH) behaved in anisobidentate fashion via carboxylate moiety. The ligand and metal complexes are also screened for their antibacterial and antifungal potential and found non-significant activities by most of the complexes, luminescent studies were also made and found Bi-L3 appreciably luminescent.