Zinc-containing Compounds Research Articles

Atomic insights into the interaction mechanism underpinning carbonate ion adsorption in smithsonite flotation

In industrial practice, smithsonite flotation separation and purification are nearly invariably conducted in highly alkaline environments. According to latest studies, sodium carbonate is a cheap, sustainable, stable, and safe substitute pH modifier that additionally assists with deep extraction recovery of smithsonite. In this work, the influence of carbonate as a pH modifier on smithsonite flotation behavior was comprehensively explored through flotation experiments, contact angle tests, X-ray photoelectron spectroscopy (XPS) investigations, and density functional theory (DFT) calculations. In comparison to sodium hydroxide, smithsonite exhibits far better floatability and hydrophobicity in the carbonate system, as demonstrated by the results of micro-flotation and contact angle experiments. XPS demonstrates that the underlying reason of the distinct pH modifications of smithsonite floatability in the carbonate system is the creation of different zinc-containing compounds, with the highly reactive CO32- forming a Zn5(CO3)2(OH)6 complex with Zn atoms at pH 10.5. Comprehensive DFT calculations further demonstrated that the hybridization reactions between Zn 2 s, O 2 s, and O 2p orbitals and the formation of stable Zn-O covalent bonds between OH- and Zn atoms shielded the preferential adsorption of oleate (OL-) on the smithsonite surface. Uniquely, the ionic bonding generated by carbonate is distinguished by the formation of a low-bonding-capacity Zn-O chemical bond, causing it susceptible to breaking during adsorption competition and allowing OL- to adsorb preferentially on Zn sites.

Investigation of the synthesis of nanostructures with increased photoluminescence obtained by depositing ultrathin layers of ZnO to the surface of porous silicon

Determining the features of the formation of hierarchical structures based on the interactions of elementary particles is a promising area of research. The deposition of 20 and 25 layers of zinc oxide by spray pyrolysis on the Si surface with stepped porosity led to the formation of ZnO particles of various sizes. X-ray fluorescence spectroscopy revealed zinc-containing compounds in thin formed layers. The maximum photoluminescence intensity and peaks characteristic of nanosized zinc oxide were found for a sample with 25 film layers. The mechanism of nanocrystal formation includes the capture of charges on oxygen vacancies.

Zinc and Zinc Transporters in Dermatology.

Zinc is an important trace mineral in the human body and a daily intake of zinc is required to maintain a healthy status. Over the past decades, zinc has been used in formulating topical and systemic therapies for various skin disorders owing to its wound healing and antimicrobial properties. Zinc transporters play a major role in maintaining the integrity of the integumentary system by controlling zinc homeostasis within dermal layers. Mutations and abnormal function of zinc-transporting proteins can lead to disease development, such as spondylocheirodysplastic Ehlers-Danlos syndrome (SCD-EDS) and acrodermatitis enteropathica (AE) which can be fatal if left untreated. This review discusses the layers of the skin, the importance of zinc and zinc transporters in each layer, and the various skin disorders caused by zinc deficiency, in addition to zinc-containing compounds used for treating different skin disorders and skin protection.

Investigation of the influence of Zinc-containing compounds on the components of the colloidal phase of milk

Abstract To solve the problem of insufficient intake of essential macro - and micronutrients into the human body, particularly in the case of the essential trace element Zinc, the possibility of enriching a socially significant product (milk) with various forms of Zinc is considered. The influence of Zinc-containing compounds on the colloidal milk system's dispersed composition and stability, photon correlation spectroscopy methods, acoustic and electroacoustic spectroscopy was established in this research. It has been shown that Zinc lysinatoriboflavinate, is a colloidal and chelated organic form of the essential trace element Zinc, having the most negligible effects on the composition and stability of the dispersed phase particles. This increases the average hydrodynamic radius of the dispersed phase by 5% and the ζ-potential by 10%. A quantum-chemical simulation of the interaction of milk κ-casein sites with various forms of the essential trace element Zinc in the QChem program was performed using the IQmol molecular editor. The mechanism of action of various forms of Zinc on the components of the dispersed system of milk, in particular milk protein (casein), is suggested.

Integrated modifying zinc-containing additive for construction silicate compositions

Sodium silicate binders are a promising binder base for obtaining effective granular thermal insulation materials. Increasing water resistance, first of all, will expand the scope of their application in construction. At the same time, the features of the modification of sodium silicate binders by compounds of polyvalent metals have not been fully studied, the interaction with which leads to the formation of hardly soluble silicates. The purpose of this work was to develop a modifying complex based on a zinc-containing compound - zinc acetate to increase the water resistance and thermal characteristics of the porous granular material. The proposed modifying additive is a complex consisting of zinc acetate and an organic alcohol solvent. It is shown that the properties of porous granular material can be controlled by changing the composition of the zinc acetate solvent. Qualitative and quantitative dependences of the properties of porous granules (strength, water resistance, density, thermal conductivity) on the type of zinc-containing solution and its content in the compositions have been obtained. The concept of the mechanism of formation of sparingly soluble complexes during the modification of sodium silicate binders with zinc-containing aqueous-alcoholic solutions has been developed. X-ray phase analysis showed that the sodium silicate system modified with an aqueous alcohol solution of zinc acetate, in contrast to an aqueous solution of zinc acetate, is completely in an amorphous state. We believe that compounds of the Zn2SiO4H2O, ZnSiO3 type are in the amorphous state. The obtained research results made it possible to determine the rational composition of granular heat-insulating material with increased operational and functional characteristics (ρ = 200-280 kg / m3, λ = 0.052-0.063 W / (m °C), R = 1.3-1.8 MPa, Kr = 0.89-0.92, W = 16- 18 %).

Corrosion Behavior of Brass H62 in Harsh Marine Atmosphere in Nansha Islands, China

The corrosion behavior of brass H62 exposed to the atmosphere of Nansha Islands for 21 months was investigated by weight loss, scanning electron microscopy, x-ray diffraction and electrochemical techniques. The results showed that the average corrosion rate of brass H62 exposed for 1 year was approximately 13.47 g m−2 a−1, and the corrosion products were observed to be unevenly distributed, attributed to the dezincification corrosion. In addition to the zinc-containing compounds Zn5(OH)8Cl2·H2O and NaZn4(SO4)Cl(OH)6·6H2O, the copper-containing compounds Cu2O and Cu2Cl(OH)3 were also detected on the front side of the exposed sample, while only the zinc-containing compounds were detected on the back side. Both sides of brass H62 showed a decreasing corrosion rate, but the corrosion product layer on the back side appeared to be more protective for the same exposure time.

The synergistic effect of zinc acetate on the protective behavior of sodium lignosulfonate for corrosion prevention of mild steel in 3.5 wt% NaCl electrolyte: Surface and electrochemical studies

In the present study, the synergistic behavior of sodium lignosulfonate-zinc acetate (SLZA) system and its consequent effect on the corrosion prevention of mild steel in the 3.5 wt% NaCl electrolyte was studied. The electrochemical and surface analyses were carried out to understand the actual corrosion inhibition action of the SLZA system. The results of electrochemical studies showed that the uniform corrosion of mild steel was synergistically suppressed due to the co-inhibition of sodium lignosulfonate (SL) and zinc acetate (ZA). The synergism parameter was about 9 and the total resistance of mild steel was >400 kΩ.cm2 in the co-presence of SL and ZA. Also, the calculated inhibition efficiency of SLZA system was about 96%. A corrosion protective system with such excellent performance is considerably rare in the literature. The co-deposition of surface barrier film consists of SL-based complexes and zinc-containing compounds was proposed as the main corrosion prevention mechanism in the presence of the SLZA system based on the results of XPS and SEM-EDS analyses.

Zinc(II) Complexes with Amino Acids for Potential Use in Dermatology: Synthesis, Crystal Structures, and Antibacterial Activity.

The multifunctional profile of Zn2+ has influenced its great popularity in various pharmaceutical, food, and cosmetic products. Despite the use of different inorganic and organic zinc derivatives, the search for new zinc-containing compounds with a safer skin profile still remains an open issue. The present paper describes the synthesis, structural characterization, and antibacterial activity of zinc(II) complexes with proteinogenic amino acids as potential candidates for dermatological treatments. The obtained complexes are of the general formula [Zn(AA)2], where AA represents an amino acid (L-Glu, Gly, L-His, L-Pro, L-Met, and L-Trp). Their synthesis was designed in such a way that the final bis(aminoacidate) zinc(II) complexes did not contain any counter-ions such as Cl−, NO3−, or SO42− that can cause some skin irritations. The chemical structure and composition of the compounds were identified by 1H NMR spectroscopy and elemental analysis, and four were also characterized by single-crystal X-ray diffraction. The Hirshfeld surface analysis for the Zn2+ metallic center helped to determine its coordination number and geometry for each complex. Finally, the antibacterial properties of the complexes were determined with respect to three Gram-positive strains, viz. Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, and Streptococcus pyogenes ATCC 19615, and two Gram-negative bacteria, viz. Escherichia coli ATCC 25992 and Pseudomonas aeruginosa ATCC 27853, and were compared with the activity of zinc 2-pirrolidone 5-carboxylate (ZnPCA), commonly applied in dermatology. It was found that the Zn(II) complexes with methionine and glycine exhibited a higher antibacterial activity than the tested standard, and the antimicrobial properties of complex with Trp were satisfactory. The results of the antimicrobial activity examination allow us to postulate that the obtained zinc complexes might become new active substances for use in dermatological products.

Advances of Zinc Signaling Studies in Prostate Cancer.

Prostate cancer (PCa) is one of the most common cancers and the second leading cause of cancer-related death among men worldwide. Despite progresses in early diagnosis and therapeutic strategies, prognosis for patients with advanced PCa remains poor. Noteworthily, a unique feature of healthy prostate is its highest level of zinc content among all soft tissues in the human body, which dramatically decreases during prostate tumorigenesis. To date, several reviews have suggested antitumor activities of zinc and its potential as a therapeutic strategy of PCa. However, an overview about the role of zinc and its signaling in PCa is needed. Here, we review literature related to the content, biological function, compounds and clinical application of zinc in PCa. We first summarize zinc content in prostate tissue and sera of PCa patients with their clinical relevance. We then elaborate biological functions of zinc signaling in PCa on three main aspects, including cell proliferation, death and tumor metastasis. Finally, we discuss clinical applications of zinc-containing compounds and proteins involved in PCa signaling pathways. Based on currently available studies, we conclude that zinc plays a tumor suppressive role and can serve as a biomarker in PCa diagnosis and therapies.

Effects of three zinc-containing sunscreens on development of purple sea urchin (Strongylocentrotus purpuratus) embryos

The growing popularity of physical sunscreens will lead to an increased release of ingredients from zinc oxide (ZnO) sunscreens into marine environments. Though zinc (Zn) is a necessary micronutrient in the ocean, greater than natural Zn concentrations may be released into marine environments by use of sunscreens. The extent of the consequences of this addition of Zn to the ocean are not fully understood. We investigated the effects of materials released by ZnO- sunscreens on the development of California purple sea urchin, Strongylocentrotus purpuratus. Embryos incubated in various concentrations of Zn (0.01, 0.05, 0.1, 0.5, and 1 mg/L), the sources of which included zinc-containing compounds: ZnO and zinc sulfate (ZnSO4); and ZnO sunscreens: All Good, Badger, and Raw Elements brands. Based on EC50 values, ZnO-containing sunscreens were slightly, but not significantly, more toxic than ZnO and ZnSO4, suggesting that sunscreens may release additional unknown materials that are detrimental to sea urchin embryo development. All concentrations of Zn-exposure resulted in significant malformations (skeletal abnormality, stage arrest, axis determination disruption), which were identified using light and fluorescence confocal microscopy. The concentration of Zn2+ internalized by the developing embryos correlated positively with the concentration of Zn in seawater. Additionally, exposure to both ZnO sunscreens and ZnO and ZnSO4 at 1 mg/L Zn, significantly increased calcein-AM (CAM) accumulation, indicating decreased multidrug resistant (MDR) transporter activity. This is one of the first studies documenting ZnO-containing sunscreens release high concentrations of Zn that are internalized by and have detrimental effects on aquatic organisms.

Promising antihypoxant in a range of complex zinc-containing derivatives of nicotinic acid

The aim of the work was to study the antihypoxic properties of a number of complex zinc-containing compounds of nicotinic acid under the code πQ. The experiments were performed on male mice of the SHR line. Antihypoxic properties of compounds were studied on 4 models of acute hypoxia (hypoxia with hypercapnia, hypobaric, hemic, and histotoxic). It was found that the compound πQ-1043 in the dose spectrum of 10-100 mg/kg effectively increases the life expectancy of animals in all models of acute hypoxia. The compound πQ-1043 at a dose of 25 mg/kg reduces the oxygen consumption and rectal temperature of animals, which can be a key factor in its anti-hypoxic action. The compound does not change glycolytic carbohydrate metabolism in animals under normal conditions, but corrects these changes in acute hypoxia. Substance πQ-1043 maintains a high content in the blood of erythrocytes and hemoglobin under hypoxic conditions. The lethal dose 50 of the compound πQ-1043 applies to moderately toxic chemicals. It is assumed that the complex zinc-containing derivative of nicotinic acid πQ-1043 is a promising compound for the development of an effective drug for the correction of hypoxic states of different genesis.

Structure formation and properties of thermochemically modified silicate-sodium compositions

Modern methods allow to improve the functional properties of silicate-sodium compositions. Increased water resistance primarily will allow their use in construction. The article presents the results of the study of modified silicate-sodium compositions by X-ray phase analysis, differential thermal analysis, thermo-gravimetric analysis. An organic zinc-containing compound, zinc acetate dihydrate, which is introduced into the binder in the form of a concentrated aqueous fluid, was used as a modifier. Using X-ray analysis, it was shown that in the hardening system “silicate-sodium binder an aqueous fluid of zinc acetate” in the temperature range 110-450°C various forms of hydroxides, silicates and zinc silicates are formed. In addition, at T = 450°C, only “traces” of ZnO were detected, and the crystalline phase of the hardly soluble zinc metasilicate ZnSiO3 prevailed. The results of the study of modified samples by thermal analysis indicate the processes of thermal decomposition of the modifying additive in the binder system and indicate the possible formation of a new crystalline phase (ZnSiO3) at a temperature of 440-450°C. It was revealed that temperature treatment of modified samples in the range of 440-450°C leads to a more significant increase in water resistance (by 25-28%) than during low-temperature curing (by 20-23%).

Improvement of Dysgeusia by Polaprezinc, a Zinc-L-carnosine, in Outpatients Receiving Cancer Chemotherapy.

Dysgeusia is one of the adverse events frequently affecting patients undergoing cancer chemotherapy. Dysgeusia-induced anorexia could decrease patient's quality of life. The present study was designed to determine whether the zinc-containing compound polaprezinc improves chemotherapy-induced dysgeusia. The incidence of grade 2 dysgeusia was assessed in 634 patients receiving cancer chemotherapy in outpatient settings during January 2013 and June 2017. Polaprezinc was administered to patients showing grade 2 dysgeusia and the effect was compared with that in patients subjected to follow-up observation. Grade 2 dysgeusia appeared in 80 patients (12.6%), in whom pancreatic cancer and treatment with fluoropyrimidines were significant risks for dysgeusia. Polaprezinc, when administered to patients with grade 2 dysgeusia, significantly shortened the duration of dysgeusia compared with that in the follow-up observation group. Subgroup analysis indicated that polaprezinc was less effective in patients with pancreatic cancer, those receiving gemcitabine, or those whose age was 65 year-old and over. Chemotherapy-induced dysgeusia occurred with high frequency in patients with pancreatic cancer or in those receiving fluoropyrimidines. Polaprezinc was highly effective in improving the symptom of dysgeusia, except for patients with pancreatic cancer, those receiving gemcitabine and the elderly.

Zinc-containing compounds for personal care applications.

It is well-known that zinc ions are widely used in cosmetic products. Their popularity is associated with the multifunctional profile of Zn2+ , which is classified as an essential chemical element in the human body. This review examines numerous beneficial biological properties of zinc-containing compounds and classifies the compounds used in cosmetic products according to their functionality profile: antioxidant, sunscreen, anti-inflammatory, anti-pigmentation, anti-ageing, anti-acne, antimicrobial, anti-odour, cleansing or stabilizing activity. It also underlines the significance of zinc in enzymatic processes, which depends on the enzyme type acts as inhibitor or enzymatic stimulator. Moreover, the article describes the chemical nature of the most interesting groups of Zn compounds.

Metal-Organic Frameworks as Sorbents for Purification of Vegetable Oils

The ability of cobalt-, iron-, and zinc-containing framework compounds to take up impurities (free fatty acids and peroxide compounds) from linseed, false fl ax, and sunfl ower oil was studied. These framework structures improve the physicochemical properties and quality of the vegetable oils tested. The metal-organic frameworks surpass in performance the traditionally used industrial and natural sorbents. The sorbents tested preserve the performance for no less than five cycles.

Experimental evaluation of acute toxicity heterometalic new compounds – tartratogermanat cooper and zinc

One of the possible ways of creating new drugs is aiming synthesis of compounds previously envisaged activity. Perspective in this area is to obtain complexes based on metal ions and ligands. Purpose : To establish toxikometric characteristics of new biologically active substances - tartratogermanat copper and zinc in the acute experiment. Materials and Methods : Studied acute toxicity in mice and rats under the conditions of oral (o), subcutaneous (s / c) and intraperitoneal (i / p) administration. The toxicity criterion of the test compounds was LD50, which was determined using the probit analysis method. In addition, a number of integrated toxicity indicators were calculated, in particular absolute toxicity, an acute toxic effect zone, a summary toxicity index and etc. The results : According to the results, the LD 50 index of copper-tartratogermanate in mice was 36.88 mg / kg (i / p) 63.78 mg / kg (s / c) and 385.57 mg / kg (o); in rats - 78.16; 135.05 and794.26 m / kg, accordingly. The LD50 index of zinc-tartratogermanate in mice was 87.20 mg / kg (i / p) 167.05 mg / kg (s / c) and 1675.40 mg / kg (o); in rats - 141.57; 236.52 and 2792.45 μ / kg, accordingly. The new compound of zinc tartratogermanat belongs to low-toxic compounds (IV class of toxicity) in conditions of intraperitoneal, subcutaneous and oral administration in two animal species, in the same time-tartratogermanat copper is moderately toxic (toxicity class III). Zinc-containing compounds showed lower toxicity than similar compounds with cuprum. According to the resalts, the variability of the lethal doses for various routes of administration of copper tartrate-hommanate was 1.32-1.60 (in mice) and 1.66-1.92 (in rats) zinc tartrate-germanate, 1.31-1.50 (in mice) and 1.24-1.37 (in rats). Integral safety of the new BAС showes that compounds with zinc were more safety in oral take, while new compounds containing copper were the safest under conditions of injection. Conclusions : A small toxicity of new compounds tartratogermanat zinc and copper indicates the prospects for their further preclinical studies as potential drugs.a.

Evidence for an in Situ Developed Polymer Phase in Ionic Elastomers

The overall mechanical performance of ionic elastomers, such as carboxylated nitrile rubber (XNBR), is largely governed by ionic clusters formed during the cross-linking of the elastomers with zinc oxide. These ionic aggregates promote microphase separation and show additional high-temperature relaxation behavior in dynamic mechanical analysis. In this study, the nature of these ionic aggregates is explored for the first time. We find that some zinc-containing compounds, such as zinc–aluminum-layered double hydroxide and zinc chloride, do not exhibit any extra high-temperature dynamic mechanical relaxation processes, although ionic cross-linking reactions with XNBR occur with all of these zinc compounds. Detailed analysis by Fourier-transform infrared spectroscopy and dynamic mechanical analysis revealed that this high-temperature relaxation behavior does not originate from ionic cross-linking but is associated with the formation of an additional zinc-enriched polymer phase that arises due to reactions between carboxylic groups and zinc oxide. Infrared spectroscopic investigation indicates further that a tetrahedrally coordinated complex facilitates the formation of a zinc–carboxylic polymeric network. Clear microphase separation of the ionic polymer in the elastomer could be directly visualized by transmission electron microscopy for the first time.

Extraction of zinc-containing products from metallurgical sludge of low zinc content using a method of filtration combustion

The possibility of recovery of zinc and zinc-containing compounds from real technogenic waste, metallurgical sludge containing about 1.0% zinc by a filtration combustion method was studied. This method due to its features is distinguished by low energy consumption and can be effectively applied in cases where the use of traditional methods is economically unjustified. In a wide range of control parameters conditions of combustion of slurry samples, the degree of extraction of zinc-containing products were found. The optimal process conditions were determined, under which recovery of zinc from poor sludge (∼1.0% Zn) was possible.

Temperature-dependent changes of physicochemical and tribological properties of acrylonitrile-butadiene rubber elastomer upon ageing in hexadecane and diethylene glycol dibutyl ether

Acrylonitrile-butadiene rubber elastomers are widely used in seal and tire industries. Physiochemical, surface and tribological properties of acrylonitrile-butadiene rubber exposed to a lubricant in a sealed mechanical contact may gradually change, in particular, at elevated temperatures. In this study, industrial-grade acrylonitrile-butadiene rubber elastomers were aged in two model non-additivated base oils, namely non-polar hexadecane and polar diethylene glycol dibutyl ether at both ambient (298 K) and elevated (398 K) temperatures from 1 to 168 h. Mass changes of acrylonitrile-butadiene rubber before and after ageing indicated that acrylonitrile-butadiene rubber had distinct ageing dynamics in different model base oils and at different temperatures. For acrylonitrile-butadiene rubber aged in nonpolar hexadecane, the rate of weight loss of the rubber was larger at 398 K compared to that at 298 K. On the contrary, distinct weight-gaining (swelling) dynamics were observed for acrylonitrile-butadiene rubber aged in polar diethylene glycol dibutyl ether at 298 and 398 K. Based on Fourier transform infrared spectroscopy, liquid and solid-state nuclear magnetic resonance spectroscopy and energy dispersive spectroscopy analyses, it was found that aldehydes and sulfur- and zinc-containing compounds were leached out from acrylonitrile-butadiene rubber aged in both hexadecane and diethylene glycol dibutyl ether. The results of tribological studies showed that the non-aged acrylonitrile-butadiene rubber has a good wear-resistance. Acrylonitrile-butadiene rubber samples had a very similar surface topography before and after tribo-tests. However, the worn surfaces of acrylonitrile-butadiene rubber samples were characterized by fine scoring (abrasion) marks after ageing in both model base oils. This has been attributed to changes in the steel–rubber contact environment during the sliding process and degradation of mechanical properties of acrylonitrile-butadiene rubber after ageing. For one acrylonitrile-butadiene rubber sample (after ageing in hexadecane at 398 K), very stable friction in the steel–rubber contact was observed.

Zinc recovery from franklinite by sulphation roasting

Residues from the zinc roast–leach–electrowin process contain zinc mainly as finely dispersed particles of franklinite. Thus, floatation, sulfuric acid leaching, and alkali leaching are ineffective methods for zinc extraction. An efficient technique was used for the extraction of zinc from hydrometallurgical zinc residues by sulfate roasting of a residue–sulfur–oxygen–H 2O mixture followed by water leaching. The effects of various parameters, such as roasting temperature/time, the sulfur amount, leaching time/temperature, and liquid/solid ratio on zinc leaching were studied. Systematic studies indicate that high zinc leaching rate can be achieved under the following conditions: sulfur addition, 1.2 times theoretical value; duration, 2 h; temperature, 250 °C at roasting stage; and room temperature, liquid/solid ratio 4, and duration time 0.5 h at leaching. X-ray diffraction analysis indicates that the zinc-containing compounds convert into water-soluble zinc sulfate after roasting.