Low Zn Concentrations Research Articles

Deciphering the interaction of heavy metals with Geobacter-induced vivianite recovery from wastewater

Vivianite recovery from wastewater driven by Geobacter is one of the promising approaches to address the challenges of phosphorus (P) resource shortage and eutrophication. However, the interfere of heavy metals which are prevalent in many actual wastewater with this process is rarely reported. In this study, we investigated the impact of heavy metals (i.e., Cu and Zn ions) on microbial activity, Fe reduction, P recovery efficiency, and their fate during Geobacter-induced vivianite recovery process. The experimental results showed that low and medium concentrations of Cu and Zn prolonged the Fe reduction and P recovery time but had little effect on the final P recovery efficiency. However, high concentrations of Cu and Zn ultimately inhibit vivianite formation. In addition, the different concentrations of Cu and Zn showed different effects on the morphology of the recovered vivianite. The migration of Cu and Zn was analysed by stepwise extraction of heavy metals in the vivianite. Medium concentrations of Cu and Zn were more likely to co-precipitate with vivianite, while adsorption was the primary mechanism at low concentrations. Furthermore, there were differences in the fate of Cu and Zn, and a competition mechanism was observed. Finally, we found that increasing the Fe/P ratio can significantly reduce the residues of heavy metals in vivianite. It also increased the adsorbed Cu and Zn proportion and reduced co-precipitation. These results provide insights into improving the efficiency of vivianite recovery and managing the environmental risks of heavy metal in the recovered product.

Elucidating the promotional effect of ultra-low Zn content on Cu for CO2 hydrogenation to methanol

CO2 hydrogenation to methanol is currently of great importance for energy and environmental objectives. Herein, the effect of ultra-low amounts of Zn on Cu/SiO2 catalysts for CO2 hydrogenation was studied, maintaining the average Cu particle size in the 2–4 nm range to minimize structure sensitivity effects. The addition of Zn amounts as low as Zn/Cu = 0.01 increases the methanol formation rate up to twelve times compared to Cu/SiO2 catalyst, highlighting the importance of isolated Zn atoms in methanol synthesis catalysis. At these very low Zn contents, CuZnX alloy sites are identified, with strong affinity for CO adsorption. When Zn content is increased, CuZn alloy disappears to give rise to mostly metallic Cu likely forming Cu-ZnOx interfacial sites. Steady state and transient Operando-DRIFTS evidence that the reaction pathways depend on the nature of the active sites with reverse water–gas shift and CO hydrogenation dominant for low Zn content catalysts and formate pathway for high Zn content catalysts.

In Situ Trace Element and Sulfur Isotope Composition of Pyrite from the Beiwagou Pb-Zn Deposit, Liaodong Peninsula, Northeast China: Implications for Ore Genesis

The Beiwagou Pb-Zn deposit, located in the western part of the Liaodong Peninsula, is a carbonate-hosted stratiform deposit with a Pb + Zn reserve of 0.08 Mt @ 4.14% (Pb + Zn). The orebodies occur as conformable layers and lenses and are strictly controlled by strata (the Paleoproterozoic Gaojiayu and Dashiqiao Formations) and lithology (plagioclase amphibolite and dolomitic marble). Given that previous studies have focused only on the mineralization features and mineralogy of deposits, herein, we report in situ trace element analyses of pyrite using LA-ICP-MS, together with in situ sulfur isotopes of pyrite, to constrain the composition, substitution mechanisms, source of sulfur, and sulfate reduction pathways of pyrite in the Beiwagou deposit. Based on pyrite morphology, texture, and chemistry, four pyrite types were identified: subhedral, porous-to-massive pyrite (Py1) related to chalcopyrite; subhedral, porous crushed pyrite (Py2) associated with fine-grained sphalerite; rounded and porous pyrite (Py3) related to the Zn-rich part of the laminated ore; and anhedral, porous-to-massive pyrite (Py4) associated with pyrrhotite, arsenopyrite, sphalerite, and galena. Py1 is characterized by high As, Ag, Cd, In, Au, Cu, and Zn concentrations and low Te, Bi, and Mo concentrations, whereas Py2 has high concentrations of Co and Ni and low concentrations of other trace elements, such as Cu, Zn, Bi, and Te. Py3 is characterized by elevated As concentrations, low Co, Ni, In, W, Te, and Tl concentrations, and varying Pb concentrations, whereas Py4 has low Ag, Cd, In, Zn, Cu, and Mn concentrations and varying W, Co, Ni, Pb, Sb, and As concentrations. Significant correlations between some elements in each pyrite type suggest substitution mechanisms, such as (Zn2+ + Cu2+ + Mn2+ + Cd2+) ↔ 2Fe2+, Ag+ + (Sb)3+ ↔ 2Fe2+, and (Te+ + Ag+) + Sb3+ ↔ 2Fe2+, and the existence of a negative correlation between Co and Ni implies competition between both elements. The strongly positive δ34S values (12.11‰–23.54‰) are similar to that of seawater sulfates and likely result from thermochemical sulfate reduction (TSR). In conclusion, the Beiwagou Pb-Zn deposit is a typical SEDEX deposit and mineralization likely occurred during diagenesis.

Association between female circulating heavy metal concentration and abortion: a systematic review and meta-analysis.

This study aimed to evaluate the association between blood heavy metal (zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)) concentrations and spontaneous abortion (SA) and recurrent pregnancy loss (RPL) and explore the possible endocrine dysfunction associated with it. A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2023. The overall effects were expressed as the standard mean difference (SMD). Subgroup analysis was performed according to the type of abortion (SA or RPL). Stata 16.0 was utilized for data analysis. Based on the integrated findings, abortion women showed significantly lower Zn (SMD = -1.05, 95% CI: -1.74 to -0.36, p = 0.003) and Cu concentrations (SMD = -1.42, 95% CI: -1.97 to -0.87, p <0.001) and higher Pb (SMD = 1.47, 95% CI: 0.89-2.05, p <0.001) and Cd concentrations (SMD = 1.15, 95% CI: 0.45-1.85, p = 0.001) than normal pregnant women. Subgroup analysis showed that Zn and Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with RPL, whereas Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with SA. Zn and Cu deficiencies and Pb and Cd exposure were associated with abortion. Endocrine dysfunction, such as insulin resistance, vitamin D insufficiency, and abnormal thyroid and sex hormone concentrations, is thought to be involved in heavy metal-related abortion.

Localized Corrosion Behavior and the Relationship to the Second Phases in Biodegradable ZX21 Mg Alloy in Hanks' Balanced Salt Solution

Mg alloys are considered promising biodegradable implant materials owing to their high activity, which makes Mg alloys degradable in the human body and can avoid second removal surgeries. Also, compared with other biodegradable implant materials, Mg alloy has a similar density and Young’s modulus to human bones, which minimizes the stress shielding effect. ZX series Mg alloys, which contain Zn and Ca, are designed to increase the alloy strength but maintain biocompatibility. However, even with all the advantages, the high degradation rate limits the clinical applications of ZX series Mg alloys. With fast degradation, not only the mechanical properties are affected, but also a large amount of hydrogen gas and hydroxide ions would accumulate around the implant in the patient. Therefore, it is essential to investigate the corrosion mechanism of the ZX series Mg alloys to mitigate the degradation rates.Localized corrosion is one of the noticeable features in the corrosion process of ZX series Mg alloys, which is the main reason for the low corrosion resistance and high degradation rate of the alloy. However, the origin and detailed mechanism of the initiation and propagation of localized corrosion on ZX series Mg alloys are still unclear. The second phases, which contain Zn and Ca, play complex roles in the corrosion process owing to the inhomogeneous elemental distribution and different electrochemical potentials with respect to the Mg alloy matrix. Thus, this study aims to investigate the microstructure of the localized corrosion sites and the galvanic effects around the second phases in a ZX series Mg alloy.In this study, an Mg-2 wt%Zn-1 wt%Ca (ZX21) alloy was prepared, and the localized corrosion behavior was investigated in a Hanks’ balanced salt solution (HBSS) at 37°C. By scanning electron microscope (SEM)/focused ion beam (FIB) cross-sectional observations, two kinds of second phases were identified in the ZX21 Mg alloy, one is enriched with Zn and the other is not. After immersion in HBSS, galvanic corrosion sites were found in the Mg alloy matrix next to the second phase enriched with Zn, while the Mg alloy matrix next to the second phase with lower Zn concentration was intact. Furthermore, the second phases in the ZX21 Mg alloy were found to hinder the propagation of localized corrosion. The complex roles of the second phases in the ZX21 Mg alloy on the localized corrosion behavior will be discussed based on electrochemical measurements and microstructure characterizations. Figure 1

Investigating the efficacy of tartaric acid and zinc-mediated endogenous melatonin induction for mitigating arsenic stress in Tagetes patula L.

In order to enhance plant growth and productivity, various chemicals and substances are commonly employed, wherein their effectiveness is influenced by factors such as concentration and growth stage. This study aimed to investigate the impact of arsenic stress on Tagetes patula L. and evaluate the potential alleviating effects of zinc (Zn) and tartaric acid. The findings revealed that low concentrations of Zn and tartaric acid effectively protected Tagetes patula L. from the adverse effects of heavy metal stress. Zinc exhibited a crucial role in plant physiology by stimulating enzyme activity and defense mechanisms. Furthermore, moderate concentrations of Zn and tartaric acid were observed to promote plant growth and increase chlorophyll content. Notably, the combined application of Zn and tartaric acid exhibited the most significant improvements in plant morphology and chlorophyll levels. Additionally, the treatments with low concentrations of Zn and tartaric acid resulted in reduced oxidative stress, as evidenced by decreased levels of hydrogen peroxide and malondialdehyde (MDA) content. Moreover, the application of zinc and tartaric acid positively influenced total soluble protein levels and relative water content. The combined treatment also enhanced the activities of antioxidant enzymes, thereby mitigating oxidative damage induced by arsenic stress. Furthermore, the synergistic effect of the Zn and tartaric acid treatment effectively alleviated arsenic-induced oxidative stress and increased the concentration of melatonin. Proline accumulation exhibited an increase under various treatments, with the combination of Zn and tartaric acid showing the most favorable impact. The resting membrane potential (RMP) of the plants was influenced by different treatments, with consistent effects observed in the combined Zn and tartaric acid treatment. Additionally, the combination of targeted amendments (TA) and Zn treatments proved beneficial in reducing soil pollution indicators. In conclusion, the synergistic application of Zn and tartaric acid demonstrated promising effects in mitigating arsenic-induced stress and optimizing the growth and physiology of Tagetes patula plants.

Prediction of low Zn concentrations in soil from mountainous areas of central Yunnan Province using a combination of continuous wavelet transform and Boruta algorithm

ABSTRACT Accurately predicting heavy metal concentration in soils is essential for agricultural production and food safety. The hyperspectral technique provides a feasible method for rapidly determining heavy metal concentration. In this study, we use spectral and Box-Cox transformations to pre-process the spectral and soil Zn concentration data to solve the problem of low prediction accuracy caused by the non-normal distribution of soil Zn concentration and the unobvious spectral characteristics. The characteristic wavelengths were selected using competitive adaptive reweighted sampling (CARS) and Boruta algorithms. Back propagation neural network (BPNN) was used to predict the low Zn concentration in the soil. The results showed that the accuracy of the models was mostly improved after Box-Cox transformation for low Zn concentration; both continuous wavelet transform (CWT) and fractional order differential (FOD) could explore the delicate features of the spectra to different degrees; the Boruta algorithm could select the wavelengths that were more relevant to Zn; the best performance could be obtained by combining CWT and Boruta algorithms, where the L5-Boruta model had the highest prediction accuracy with R2, RMSE and RPIQ of 0.656, 13.050 mg∙kg−1 and 2.351, respectively.

Purification and biochemical characterization of a novel carbonic anhydrase II from erythrocytes of camel (Camelusdromedarius)

A novel carbonic anhydrase II (CA II) from erythrocytes of camel (Camelus dromedarius) was purified to homogeneity using affinity chromatography and biochemically characterized. Specific activity of 140.88 U/mg was obtained with 745.17-fold purification and 25.37% yield. The enzyme was a monomer with a lower molecular weight (25 kDa) and lower Zn content (0.50 mol of Zn per mol of protein). The enzyme showed higher optimum temperature (70 °C) and pH (pH 9.0), moreover, it was stable at higher temperatures and strongly alkaline pH as judged by thermodynamic parameters (Ea, kd, Ed, t1/2, D-value, Z-value, ΔH, ΔG and ΔS). The enzyme was inhibited by cations (Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Mg2+ and Zn2+) as well as by anions (Br‾, CH3COO‾, ClO4‾, CN‾, F‾, HCO3‾, I‾, N3‾, NO3‾ and SCN‾), some anions (C6H5O73−, CO32−, SeO3‾ and SO42−) does not affect enzyme activity. Effect of various chemicals on enzyme activity was also investigated. Km, Vmax, kcat and kcat/Km values for 4-NPA were found to be 1.74 mM, 0.0093 U/mL, 0,0039 s−1 and 0,0023 s−1 mM−1, respectively. With these interesting biochemical properties, camel CA II represents promising candidate for harsh industrial applications, in particular, for a successful biomimetic CO2 sequestration process.

Investigating the Mechanism by Which Intragap States Tailor Light Emission: Case of Copper Deficient and Zn Doped Cu−In−Se Quantum Dots**

AbstractThe large structural tolerance of I–III–VI group quantum dots (QDs) to off‐stoichiometry allows their photoluminescence properties to be adjusted via doping, thereby enabling application in different fields. However, the photophysical processes underlying their photoluminescence mechanism remain significantly unknown. In particular, the transition channels of CuInSe2 QDs, which are altered by intrinsic and extrinsic intragap states, remain poorly reported. Herein, we investigated the photophysical processes associated with intragap states via electrochemical and optical techniques by using copper deficient Cu−In−Se QDs as well as Zn doped Cu−In−Se QDs. When the Cu/In molar ratios of Cu−In−Se QDs increased from 0.3 : 1 to 0.9 : 1, the photoluminescence spectra displayed a red‐shift from 700 nm to 1050 nm. Although there was a blue‐shift after the introduction of Zn2+ dopants in Cu−In−Se QDs, a significant red‐shift occurred (from 660 nm to 760 nm) when the Zn/Cu molar ratios decreased from 0.7 : 0.3 to 0.3 : 0.7. The Gaussian deconvolution results of the photoluminescence spectra and the band gap derived from absorption spectra by fitting supported the fact that the optical transition channels are dependent on the Cu/In and Zn/Cu molar ratios. After the introduction of the Zn2+ ions, the alloyed‐resultant blue‐shift of the emission spectra was observed, primarily due to the enlarged band gap; however, the radiative recombination of prominent intrinsic intragap states is still observed; and only a small proportion of the band‐edge exciton undergoes recombination for the sample with low Zn content. Cyclic voltammetry measurements revealed well‐defined extrinsic ZnCu intragap states (Zn substitution on Cu sites) and intrinsic Cux (x= 1+/2+) states in the band gap. The results presented here provide a better understanding of the varying effects of dopant on photoluminescence in terms of I–III–VI group QDs.

Effect of Zn content on microstructure evolution in Al–Zn alloys processed by high-pressure torsion

Al–Zn alloys having different Zn contents of 2, 5, 10 and 30 wt% were processed by high-pressure torsion (HPT) to produce ultrafine-grained (UFG) materials. Microstructural features of these UFG Al–Zn alloys were investigated using depth-sensing indentations, focused ion beam (FIB), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Emphasis was placed on the microstructure evolution of the alloys with different Zn-concentration which demonstrated substantially different mechanical behavior, exhibiting superductility with increasing Zn content. It was shown that in every case, HPT resulted decomposition in the microstructure, but there is a significant difference between the microstructures of alloys with low and high Zn content. Based on the microstructural observations, a scenario is proposed about that how the decomposed microstructure developed during HPT process in low- and high Zn-containing Al–Zn alloys, influencing their mechanical behavior.Graphical abstract

Study on Zn-doped antibacterial bioactive coatings on Ti6Al4V titanium alloy surfaces by micro-arc oxidation

To enhance the bioactivity and antibacterial activity of titanium alloys, coatings with different content of Zn element were successfully formed on Ti6Al4V substrates by micro-arc oxidation (MAO). The microstructure and composition of the coatings were characterized, and the bioactive and antibacterial activities were evaluated by the contact angle, cell viability and plate colony counting experiments, respectively. The results show that when Zn2+ concentration of the electrolytes rises, the breakdown voltage and the process voltage decrease, while the duration of the micro-arc oxidation stage increases. The products of MAO in the coatings are mainly rutile and anatase phases. As Zn2+ concentration in the electrolyte increases, the content of crystalline phases reduces, the thickness and the surface roughness of coatings increase, and the porosity shows an increase overall. MAO coatings bond tightly to the substrates, forming a thin, dense barrier layer and a thick, porous outer accumulation layer. The increase of Zn content results in an increase of Ca and P content in the coatings and a rise in Ca/P ratio. The concentrations of Ti, O, Ca and Zn elements on the cross-section show a transition distribution. Moreover, the hydrophilicity of all coatings is improved. Zn-doped coatings improve the cell viability of preosteoblast MC3T3-E1 cells and macrophage RAW264.7 cells, and higher cell viability is observed on the coatings with higher Zn concentration. Although the MAO coatings with low Zn content increase bacterial adhesion compared to the substrate, the coatings with high Zn content show adequate antibacterial activity.

Gold source and ore-forming process of the Linglong gold deposit, Jiaodong gold province, China: Evidence from textures, mineral chemical compositions and sulfur isotopes of pyrite

The Linglong gold orefield is located northwest of the Jiaodong gold province, in the eastern North China Craton (NCC) area. It consists of over 10 gold mines with a total gold resource of approximately 1000 t, and gold mineralization occurs in gold-quartz veins. The Linglong gold deposit underwent four stages of ore-forming processes namely: Pyrite-quartz (stage I) – milky-white quartz vein with euhedral pyrites, Quartz-pyrite (stage II) – smoky quartz veins with euhedral-subhedral pyrites, Polymetallic sulfides (stage III) – quartz veins with large amounts of polymetallic sulfides (pyrite, pyrrhotite, sphalerite, galena), hematite, and native gold, and the Quartz–carbonate (stage IV) – calcite-quartz veins. This study focuses on the investigation of pyrites from three main mineralization stages (I-III), exploring their textures, in-situ major and trace element concentrations, and in-situ sulfur isotopic compositions.The study examined pyrite through various methods including BSE and EMPA major element, LA-ICP-MS trace element, and LA-MC-ICP-MS sulfur isotope analyses. Pyrite from three distinct stages of ore-forming processes were analyzed. Pyrites from stage I (Py-I) exhibited euhedral crystals with homogeneous brightness in the BSE, lacked mineral inclusions, porous microtextures, and oscillatory zones. Py-I possessed low contents of Au, Ag, As, Bi, Cu, Sb, Zn, Co, and Ni. Pyrites from stage II (Py-II) showed fine-coarse grains and euhedral-subhedral features with slight fractures, similar to Py-I, however, had the higher concentrations of As and Sb. Pyrites from stage III (Py-III) were found in the quartz-polymetallic sulfide veins and exhibited subhedral to anhedral features and more significant concentrations of metallic elements, particularly Au and As. The δ34S values of Py-I, Py-II and Py-III were in the ranges of 6.76‰–7.47‰, 6.11‰–7.27‰ and 6.07‰–8.33 ‰, respectively. Analysis of the texture and geochemical composition of pyrite suggested that invisible gold was primarily present in pyrite in the form of solid solution (Au+), accompanied by a small amount of nano-form gold. The ore-forming fluids that led to this mineralization were mostly derived from mantle-derived mafic magma mixed with some minor metamorphic sedimentary material. A decrease in fluids temperature, water–rock interactions and fluid boiling led to the depositions of sulfides and gold. In the Late Mesozoic, lithospheric delamination of the eastern block of the NCC triggered decompression and melting of the upwelling asthenospheric mantle resulting in partial melting of the lithospheric mantle. This lithospheric mantle-derived mafic magma provided the ore-forming fluids for large-scale gold mineralization in the Jiaodong gold province.

Spatial assessment of topsoil zinc concentrations in Europe

Zinc (Zn) is essential to sustain crop production and human health, while it can be toxic when present in excess. In this manuscript, we applied a machine learning model on 21,682 soil samples from the Land Use and Coverage Area frame Survey (LUCAS) topsoil database of 2009/2012 to assess the spatial distribution in Europe of topsoil Zn concentrations measured by aqua regia extraction, and to identify the influence of natural drivers and anthropogenic sources on topsoil Zn concentrations. As a result, a map was produced showing topsoil Zn concentrations in Europe at a resolution of 250 m. The mean predicted Zn concentration in Europe was 41 mg kg−1, with a root mean squared error of around 40 mg kg−1 calculated for independent soil samples. We identified clay content as the most important factor explaining the overall distribution of soil Zn in Europe, with lower Zn concentrations in coarser soils. Next to texture, low Zn concentrations were found in soils with low pH (e.g. Podzols), as well as in soils with pH above 8 (i.e., Calcisols). The presence of deposits and mining activities mainly explained the occurrence of relatively high Zn concentrations above 167 mg kg−1 (the one percentile highest concentrations) within 10 km from these sites. In addition, the relatively higher Zn levels found in grasslands in regions with high livestock density may point to manure as a significant source of Zn in these soils.The map developed in this study can be used as a reference to assess the eco-toxicological risks associated with soil Zn concentrations in Europe and areas with Zn deficiency. In addition, it can provide a baseline for future policies in the context of pollution, soil health, human health, and crop nutrition.

Effects of laser energy on the surface quality and properties of electrodeposited zinc-nickel-molybdenum coatings

As a substitute for toxic cadmium coatings in the aerospace industry, zinc-nickel coatings have excellent application prospects, and their properties can be improved by adding molybdenum. In this study, laser-assisted electrodeposition is used to improve the surface quality and properties of Zn–Ni–Mo coatings, with investigation of how laser energy in the range of 0–21.1 μJ affects their element content, surface morphology, crystal phase, microhardness, residual internal stress, and corrosion resistance. The laser irradiation accelerates the electrodeposition, refines the grain size, improves the hydrogen adsorption, and reduces the residual tensile stress, and a laser energy of 15.4 μJ gives the highest Ni and Mo contents and the lowest Zn content, as well as the optimum surface morphology, microhardness, residual internal stress, and corrosion resistance of the coating.

High-throughput profiling the effects of zinc on antibiotic resistance genes in the anaerobic digestion of swine manure

ABSTRACT The problem of antibiotic resistance genes (ARGs) caused by heavy metals has attracted extensive attention of human beings. Zn, a widely used feed additive, has a very high residue in swine manure, but the distribution characteristics of ARGs imposed by Zn in anaerobic digestion (AD) products are not clear. In this study, the behaviour of mobile genetic elements (MGEs), bacterial community, and their association with ARGs were determined in the presence of 125 and 1250 mg L–1 Zn in AD system of swine manure. Zn-treated enriched the abundance of ARGs, and produced some new genotypes that were not detected in CK treatment. In addition, low concentration of Zn significantly increased the relative abundance of ARGs, as compared to higher Zn and CK group. Correspondingly, the abundances of most top30 genus were highest in ZnL (125 mg L–1 Zn), followed by CK and ZnH (1250 mg L–1 Zn). Notably, network analysis showed that the relationship between ARGs and MGEs is closer than that ARGs and bacteria, suggesting that ARGs increased in Zn-treated, especially low level Zn, may be due to the amplification transfer of ARGs among varied microorganisms by horizontal transfer with MGEs. Therefore, strengthen the management of in livestock manure is crucial to control the spread of ARGs in organic fertilizers.

Diffusion-driven Zn and Mg isotope fractionation in magmatic Fe-Ti-Cr oxides and implications for timescales of magmatic processes

Diffusion-driven isotopic fractionation during crystal growth and crystal-melt interaction has important implications for identifying diffusive processes and estimating the timescales of magmatic processes. Especially, Fe-Ti-Cr oxides are common crystalline phases in both relatively unfractionated and highly evolved basaltic magmas and may record the evolution history of the host magmas. High-precision Zn and Mg isotopic compositions for a set of Fe-Ti-Cr oxides and their host lavas in three types of Cenozoic basalts (sodic, transitional and potassic) from northeast China are reported in this study. These oxide crystals exhibit a wide range of chemical compositions (e.g., FeOT = 20.6–49.1 wt%, TiO2 = 1.38–8.70 wt%, Cr2O3 = 16.2–43.1 wt%), reflecting substantial chemical disequilibrium with their host magmas. A large range of δ66ZnJMC-Lyon from −1.12‰ to 0.24‰ and δ26MgDSM-3 from 0.04‰ to 0.80‰ is observed in oxides (n = 17) from all three lava types. Compared with the host basalts, the oxides are enriched in lighter Zn with △66Znoxide-melt (δ66Znoxide–δ66Znmelt) from −1.43‰ to −0.19‰ and heavier Mg with △26Mgoxide-melt (δ26Mgoxide–δ26Mgmelt) from 0.43‰ to 1.13‰. Comparison with existing theoretical work indicates that these isotopic offsets, even if compositional effects of oxides are considered, are too large to be in equilibrium. There are negative correlations between tetrahedral-site Fe2+ + Zn2+ and Mg2+ (R2 = 0.97) and between δ66Zn and δ26Mg (R2 = 0.66) for the oxides, which are best attributed to isotopic fractionation induced by Zn–Mg inter-diffusion, supported by the core-to-rim increase of Zn contents and decline of Mg contents in zoned oxides. Our results thus suggest that inter-diffusion between Mg and Zn can occur during crystal growth and reaction with host magmas, which is commonly observed between Mg and Fe, and this process is accompanied by strong Zn and Mg isotope fractionations. Such fractionations can be utilized to estimate the timescales for the formation of zoned minerals. Numerical simulation yields a short (∼35 days) diffusion interval for the observed Zn and Mg isotopic variations in the investigated oxide crystals, which indicates rapid cooling of the host lavas. Our results also indicate that fractional crystallization of oxides would lead to slight δ66Zn increase and δ26Mg decrease in the residual melts. Such fractionation should be considered while characterizing the Zn and Mg isotopic compositions of evolved magmas with low MgO and Zn contents.

Zinc-Sulphate and Zn-EDTA Enhances Zn and Other Nutrients and Yield and Quality of Table-Purpose Peanut Cultivars

ABSTRACT Zinc (Zn) and iron (Fe) deficiencies in humans are major problems worldwide, which necessitate their increase in food crops. Peanut (Arachis hypogaea L.), which is a good nutritional source of Zn and Fe, is used as a table-purpose food item worldwide, but is mostly grown under poor-fertility soils, resulting in low Zn concentrations in the edible seed. In a 2-year field study, the influence of zinc sulfate and Zn-EDTA, at 2 kg Zn ha−1, was studied in 20 confectionery peanut cultivars where both of these Zn sources increased yield attributes, 100-seed weight, and Zn, P, and K concentrations in seed. The respective mean concentrations of Zn, P, and K in the seed were 43 mg kg−1 and 0.61% and 0.75% in control which increased to 50 mg kg−1 and 0.62% and 0.76%, with the application of zinc sulfate and 46 mg kg−1 and 0.63% and 0.82%, respectively, with the application of Zn-EDTA. The cultivars TG 37A, GG 7, HNG 69, ICGV 00348, CSMG 884, and BAU 13 showed high protein (25% and above), Zn (>50 mg kg−1), Fe (>75 mg kg−1), P (>0.60%), and K (>0.75%) with the application of zinc sulfate and hence are being recommended for cultivation and their use as food to ameliorate micronutrient malnutrition.

Corrosion and discharge performance of AZ61, AZ63, AZ101 and AZ103 alloys as anode in magnesium-dissolved oxygen seawater long term batteries

Distribution of phases, morphologies of discharge products, and concentration of Al and Zn elements in discharge products affect corrosion, anodic efficiency, and discharge performance of AZ61, AZ63, AZ101, and AZ103 alloys. The AZ101 alloy has a low overpotential for the dissolution of the Mg, which provided the highest OCP and the lowest discharge potential (−1.474 V vs SCE). The detachment of a large number of the β-Mg17Al12 phase particles and the loose discharge products with deep cracks on the AZ101 alloy surface provided the highest self-corrosion rate (2.225 g cm−2 year−1), the lowest anodic efficiency (41.76 ± 1.43%) and the lowest overpotential for hydrogen gas evolution. Fine β-Mg17Al12 phase particles, low concentration of Al and Zn within α-Mg, and condensed discharge products of the AZ63 alloy contribute to uniform corrosion. Despite offering a higher potential by the AZ63 alloy (−1.432 V), it has a lower chemical corrosion rate (0.476 g cm−2 year−1) and the highest anodic efficiency (56.07 ± 1.48). It suggests that AZ63 alloy is a good candidate as an anode for long-term seawater batteries.

The enhancement of mechanical properties and uniform degradation of electrodeposited Fe-Zn alloys by multilayered design for biodegradable stent applications.

Pure Fe is a potential biodegradable stent material due to its better biocompatibility and mechanical properties, but its degradation rate needs to be improved. Alloying with Zn to form Fe-Zn alloy is anticipated to meet the degradation rate requirements while retaining the iron's inherent properties. Therefore, Fe-Zn alloys with monolayered and multilayered structures were prepared by electrodeposition. The alloys' composition, microstructure, mechanical properties, in vitro degradation and biocompatibility were assessed. Results showed that the Zn content ranged from 2.1 wt% to 11.6 wt%. After annealing at 450°C, all the alloys consisted of α(Fe) solid solution and Zn-rich B2 ordered coherent phase, except for the alloy with 11.6 wt% Zn content, in which a Fe3Zn10 phase appeared. The layered structure consisted of alternating columnar-grain and nano-grain layers, which compensated for the intrinsic brittleness of electrodeposited metals and improved the galvanic effect of the alloy, thus increasing the strength and plasticity and changing the corrosion from localized to uniform while augmenting the corrosion rate. The yield strength of the multilayered alloy exceeded 350 MPa, its elongation was more than 20%, and its corrosion rate obtained by immersion test in Hank's solution reached 0.367 mm·y-1. Fe-Zn alloys with lower Zn content had good cytocompatibility with the human umbilical vein endothelial cells and good blood compatibility. The above results verified that the multilayered Fe-Zn alloy prepared by electrodeposition presented enhanced mechanical properties, higher degradation rate, uniform degradation mechanism and good biocompatibility. It should be qualified for the application of biodegradable stents. STATEMENT OF SIGNIFICANCE: A potential biodegradable Fe-Zn alloy, which is difficult to be obtained by the metallurgical method, was prepared by electrodeposition to solve the low degradation rate of iron-based biomaterials. A multilayered microstructure design composed of alternating columnar-grain and nano-grain layers was achieved by changing the electrical parameters. The layered design compensated for the intrinsic poor plasticity of electrodeposited metals. It increased the galvanic effect of the alloy, thus augmenting the corrosion rate and changing the corrosion mode of the alloy from localized to uniform corrosion. The yield strength of multilayered alloy exceeded 350 MPa; its elongation was more than 20%. Moreover, the layered alloy had good cytocompatibility and blood compatibility. It indicates that the alloy is qualified for biodegradable stent application.

Differences in Metal Accumulation from Stormwater by Three Plant Species Growing in Floating Treatment Wetlands in a Cold Climate

Stormwater is a source of pollutants in urban areas and should be treated to prevent negative environmental effects. A newer technique uses floating rafts with plants, called floating treatment wetlands (FTWs), which are placed in the polluted water. Few earlier studies have examined heavy metal removal by FTWs, and none has examined stormwater in cold climates. This study therefore aimed to determine whether plants growing in FTWs could accumulate heavy metals from stormwater ponds in a cold climate. This study examined the abilities of three native wetland species (i.e., Carex riparia, C. pseudocyperus, and Phalaris arundinacea) to accumulate Cd, Cu, Pb, and Zn. The plants were planted on FTWs, which were placed in two stormwater ponds in Stockholm, Sweden, for 12 weeks. Phalaris arundinacea accumulated more Cd, Cu, and Zn than did the Carex species, and C. pseudocyperus accumulated less Pb than did the other species during the experimental period. In most cases, the roots had higher metal concentrations than did the shoots. Carex pseudocyperus had smaller differences between shoot and root metal contents, whereas P. arundinacea had higher Cd and Cu contents and lower Zn contents in its roots than in its shoots. The metal content in the plants increased with higher biomass. The plants that grew in the stormwater pond with a higher Zn concentration had a higher Zn tissue concentration and total Zn content per plant after treatment. This study shows that wetland plants growing on FTWs can accumulate metals from stormwater ponds in a cold climate. Phalaris arundinacea appears to be a good candidate for metal removal use in FTWs. Furthermore, high plant biomass positively affects the metal uptake, meaning that good growing conditions could be essential for metal removal.