In order to improve our understanding of how the goethite crystal structure is affected by the incorporation of metals (and by variations in the amount of the incorporation), and to review any possible synergistic and antagonistic effects of co-metals, the present investigation focused on the incorporation of multiple (di-, tri-, and tetra-) metals, i.e. Cr, Zn, Cd, and Pb, in the goethite crystallographic structure. A series of single- and multi-metal M-Cr/Zn/Cd/Pb-substituted goethites with M/(M+Fe) molar ratios = 0.10 were prepared. The general sequence of metal entry in single-metal substituted goethites was Zn = Cr > Cd > Pb and in multi-metal-substituted goethites was Zn > Cr ⩾ Cd > Pb. Simultaneous incorporation of Cr, Zn, Cd, and Pb up to 10.5 mole % was achieved in goethite. Synchrotron X-ray diffraction and extended X-ray absorption fine structure (EXAFS) techniques were employed to assess the structural characteristics of the synthesis products. Rietveld refinement of XRD data showed small changes in unit-cell parameters and Fe/M-Fe/M distances due to M substitution(s). A typical goethite-like crystalline structure remained intact, however. The unit-cell parameters were mutually, linearly correlated, though Fe/M-Fe/M distances were not, indicating that complex changes occurred at the local scale. In single-metal substituted goethites, incorporation of Cr reduced the unit-cell volume by 0.13% while that of Zn, Cd, and Pb increased it by 1.09, 3.58, and 0.56%, respectively. The changes in multi-metal-substituted goethites appeared to be the complex combination of that of the individually incorporated metals. The X-ray absorption near edge structure study of Pb-substituted goethites showed that the majority of associated Pb was Pb2+, while Pb4+ was preferred over Pb2+ in the bulk structure. Measurements by EXAFS at the Fe K-edge indicated that the Fe polyhedra contracted in the presence of Cd2+ and Pb2+, providing room for the substitution of larger cations. Measurements by EXAFS at the Cr and Cd K-edges indicated symmetric Cr/Cd polyhedra with single Cr/Cd-O distances and, at Fe and Zn K-edges and the Pb LIII-edge, indicated asymmetric polyhedra with two sets of Fe/Zn/Pb-O distances. The Zn octahedra were possibly Zn(OH)4O2, which enlarged the metal-metal corner-sharing distance to 3.86 Å. This configuration of ligands around the Zn2+ cation might occur to balance local charges. Symmetric polyhedra appeared to reduce steric strains in the structure, compared to the asymmetric polyhedra. The result was that Cr enhanced the incorporation of Zn, Cd, and Pb, while the converse was true for Zn.

Although previous studies suggested the protective effect of Zn for type 2 diabetes (T2D), the unitary causal effect remains inconclusive. We investigated the causal effect of Zn as a single intervention on glycaemic control for T2D, using a systematic review of randomised controlled trials and two-sample Mendelian randomisation (MR). Four primary outcomes were identified: fasting blood glucose/fasting glucose, HbA1c, homeostatic model assessment for insulin resistance (HOMA-IR) and serum insulin/fasting insulin level. In the systematic review, four databases were searched until June 2021. Studies, in which participants had T2D and intervention did not comprise another co-supplement, were included. Results were synthesised through the random-effects meta-analysis. In the two-sample MR, we used single-nucleotide polymorphisms (SNP) from MR-base, strongly related to Zn supplements, to infer the relationship causally, but not specified T2D. In the systematic review and meta-analysis, fourteen trials were included with overall 897 participants initially. The Zn supplement led to a significant reduction in the post-trial mean of fasting blood glucose (mean difference (MD): −26·52 mg/dl, 95 % CI (−35·13, −17·91)), HbA1c (MD: −0·52 %, 95 % CI: (−0·90, −0·13)) and HOMA-IR (MD: −1·65, 95 % CI (−2·62, −0·68)), compared to the control group. In the two-sample MR, Zn supplement with two SNP reduced the fasting glucose (inverse-variance weighted coefficient: −2·04 mmol/l, 95 % CI (−3·26, −0·83)). From the two methods, Zn supplementation alone may causally improve glycaemic control among T2D patients. The findings are limited by power from the small number of studies and SNP included in the systematic review and two-sample MR analysis, respectively.

A Na-montmorillonite (Na-MMT) was activated with HNO3 (20 wt.%) solution at various temperatures and times to obtain acid-activated MMT (Acid-MMT). Zinc (4 wt.%) was supported on Acid-MMT via the impregnation method using Zn(NO3)2⋅6H2O as a precursor. The catalytic performance of the Zn/Acid-MMT for the aromatization of heptane was investigated. The amount and distribution of acidity of Acid-MMT, which could be adjusted by changing the acid activation time and temperature, significantly affected the heptane conversion and aromatics content. As a result, an efficient Zn/Acid-MMT catalyst for the aromatization reaction was obtained by optimizing the acid-treatment conditions of Na-MMT.

The dissolution of the United Kingdom’s vitrified high-level-waste simulant, CaZn MW28, was investigated following the Product Consistency Test-B protocol for 112 d at 90 °C and in ultra-high-quality water. Residual rate dissolution (stage II) and rate resumption (stage III), after 28 d, was observed. Thermodynamic modelling suggested that solutions were saturated with respect to Mg- and Zn-bearing phases, and the presence of Mg- and Zn-smectite clays was tentatively observed. The formation of these phases was concurrent with a significant increase in the dissolution rate, similar to Stage III behavior seen in other nuclear waste simulant glass materials, indicating that the addition of Mg and Zn to high-level-waste glass (7.3 wt. % combined) significantly influences the dissolution rate.

In this study, feasibility of spark discharge technique to generate mixed metal nanoparticles is demonstrated. Two immiscible metals Au and Zn are selected to prepare AuZn mixed nanoparticles. Ignition of spark between Au and Zn electrodes under normal pressure, in the presence of carrier gas, leads to formation of mixed nanoparticles by condensation and nucleation. Online particle size-distribution is monitored by a scanning mobility particle sizer on changing carrier gas flow rate and capacitor charging current during co-sparking between Au and Zn electrodes. The technique provides flexibility to generate binary mixture of AuZn nanoparticles in the size range of 10-80 nm. Distribution of Au and Zn in the prepared mixed nanoparticles is mapped by scanning electron microscopy and high resolution electron microscopy.

This study aims at establishing environmentally stable and viable silver nanowire (AgNW) electrodes of an Electrodynamic Screen (EDS) film, by the inclusion of one or more protective layers of zinc oxide (ZnO) produced in lab by combining tetrahydrofuran (THF) and diethylzinc (DEZ). The electrodes can be realized as 1) stacked structure where the AgNW electrode has a layer of ZnO on top for protection or 2) sandwiched structure where the AgNW electrode is covered by ZnO layers, protecting it from the top and bottom. Experiments are done to test the effect of accelerated exposure to ultraviolet light, high temperature and passage of high voltage on the AgNW samples and are compared with the results obtained from the AgNW samples that have the ZnO protective layer which have also been subjected to the aforementioned test conditions. A complete water immersion test is performed in order to ensure functionality and efficiency of the ZnO/AgNW samples that are to be patterned as electrodes of the EDS film. This will demonstrate viability of the structure in the case of rain.

Photochromic (PC) ZnO nanoparticles are synthesized for the first time by using a VHF plasma enhanced CVD apparatus. The prepared ZnO film changes from transparent to PC state under UV irradiation; on being subjected to heat treatment, it changes back to transparent state. There is a threshold temperature for attaining the PC phase. The Debye-Waller factor of Zn atoms is specifically large for the PC ZnO. The ZnO nanoparticles contain carbon as impurity. The effects of C-O bonds on the ZnO crystal structure and density of states (DOS) are simulated based on density-functional theory. The results reveal that the crystal structure is slightly distorted and a sufficient DOS for PC light absorption is formed in the band gap.

The present work describes a simple method to produce zinc oxide nanoparticles supported in nitrogen-doped reduced graphene oxide, ZnO/N-rGO. The rGO structures were nitrogen-doped using hydrazine as nitrogen source (N-rGO) with the purpose of enhancing the rGO capability to promote the electrons transport along their surface. Thus, ZnO/N-rGO catalytic systems were tested as photocatalyst to degrade methylene blue and lignin molecules under ultraviolet (UV) and visible (Vis) light irradiation. N-doping of rGO was confirmed by X-ray photoelectron spectroscopy (XPS). Photocatalytic degradation studies confirm better performance of the ZnO/N-rGO in comparison to ZnO. The percentage of lignin degradation for the ZnO/N-rGO compound under UV was 59%, while using visible energy it was achieved 46%, in a time of 70 min.

Aqueous rechargeable batteries are attractive owing to their higher operational safety, high ionic conductivity, scalable and easy manufacturing. These aqueous batteries form an economic option for large-scale (grid) power storage. In the aqueous battery sector, Mn-based compounds are highly attractive with their non-toxic nature, low-cost, rich mineral chemistry and robust operational safety. Several Mn-based systems like LiMn2O4 spinel and LiNi1/3Mn1/3Co1/3O2 have seen successful commercialization. Pursuing Mn-based materials, we have shown layer structured Na2Mn3O7 as a versatile cathode material for non-aqueous systems like Li-, Na- and K-ion batteries. In the current work, we have exploited Na2Mn3O7 as a cathode material for aqueous Zn-ion battery for the first time. This Na-Mn-O ternary system was prepared using two-step emulsion-based synthesis. The phase-pure Na2Mn3O7 was formed in a triclinic structure with a space group of P-1. It exhibited versatile electrochemical insertion of different ions like Li-, Na- and K-ions involving phase transition. Na2Mn3O7 exhibited reversible Zn-ion intercalation delivering capacity of 245 mA h g-1 with a nominal voltage of 1.5 V. Upon discharge, it triggered phase transformation to an unknown phase. Layered Na2Mn3O7 oxide was found to act as an efficient cathode for Zn-ion batteries with good cycling stability.

Biodegradable material was prepared from cassava starch in combination with zinc oxide nanoparticles (ZnO NPs) to give the properties of microbial growth resistance, glycerin concentrations were varied to 5%, 10%, and 20% (w/v) for the study of the rheological properties. The nanoparticles were characterized by a spectrophotometer where an exciton peak at 370 nm was obtained. The different samples were subjected to a thermomechanical study through an AR-G2 hybrid rheometer, using a parallel plane geometry of 20 mm, a weak gel behavior is observed, it is a slimming material and it is thermostable, it is also established that the zinc oxide concentration nanoparticles do not affect the mechanical behavior of the material.

In this study, silver, zinc and copper nanoparticles, AgNPs, ZnNPs and CuNPs, were tested on photodegradation using phenol as a model contaminant. The nanoparticles were phytosynthesized from an aqueous extract of Eichhornia crassipes leaves, and were characterized by UV-visible spectroscopy, EDS (Dispersive Energy X-ray Spectroscopy), SEM (Scanning Electron Microscopy), and TEM (Transmission Electron Microscopy). The AgNPs, ZnNPs and CuNPs showed a characteristic plasmon determined by UV-Vis; in the case of the EDS analyses Ag, Zn and Cu were detected as the main components. The detected composition by TEM corresponded to a metallic oxide for the three nanoparticles. Finally, for the photocatalytic performance on the phenol degradation under UV radiation, they showed about 50%, 52% and 34% with a 10 mg/L phenol solution that was achieved within 200 min using AgNPs, ZnNPs and CuNPs, respectively.

In this work, green nanotechnology has been applied by using phytochemical compounds as reducing agents from the plant extract of Hydrocotyle ranunuculoides through three modifications of the phytosynthesis method to prepare Fe and Zn nanoparticles, in three different concentration of the metallic solution. In the third modification a MgO support was included to avoid the Fe and Zn NP agglomeration. The nanoparticles size was 5±1 nm, and for the Fe NPs, it was determined with a cubic structure a Fe3O4 composition, and Zn nanoparticles were obtained with a hexagonal structure and Zn° composition. In the third method, MgO nanoparticle, the support appears as Mg0 nanoparticles surrounded by Fe0 and Zn0 nanoparticles. According to the three used methods pathways, the main influence is the modification in the method synthesis. Hybrid nanocomposites provide a means in preventing agglomeration of the NPs and hence avoid coalescence and loss of properties.

Lead, zinc and arsenic mobilization/attenuation processes during interactions between smelter slag and water show differences depending on the origin of the slag. The studied samples, waste from ore and car-battery processing, were submitted to long-term (365 days) batch leaching at two different initial pH values. The leachate analyses were input to the EQ3NR speciation-solubility code to speciate the solutions and determine the degree of saturation with respect to different phases, and a mineralogical investigation was made of the newly formed phases. An ‘oxidizing’ scenario can be proposed for slag waste disposal, considering that cerussite (PbCO3) at pH >6 becomes a major solubility-controlling phase for Pb, and newly formed hydrous ferric oxides (HFO – common secondary phases under oxidizing conditions) efficiently adsorb As. No efficient scavenging mechanism was found for Zn, which was progressively leached from the slag and in particular from the ore-processing slag. Quenched glass-rich slag from old car-battery processing was found to release significant amounts of Pb, especially in acidic environments. Neither slag would therefore be suitable for recycling for civil engineering purposes. Conversely, extremely low releases of Pb, Zn and As were observed for recent car-battery processing slag, which could therefore be considered for road construction.

X-ray absorption spectroscopy, scanning electron microscopy (SEM) and X-ray diffractometry (XRD) have been used to study the solid-phase speciation of Zn in urban road dust sediments (RDS) in Manchester, UK. X-ray absorption near-edge structure (XANES) analysis using linear combination modelling suggest that the soluble species Zn(NO3)2·6H2O and ZnCl2 represent 70—83%, and Zn-sorbed goethite 17—30%, of the Zn species present. The presence of goethite is not corroborated by extended X-ray absorption fine structure (EXAFS) modelled first shell scattering Zn—O distances of 2.01—2.03 Å, but this may be due to distortion of the Zn octahedra on the goethite surface, or the existence of Zn-sorbed species with other metal hydrous oxides, as inferred by the EXAFS-modelled second shell Fe and Al scatterers. Analysis by EXAFS also suggests that metallic Zn-Cu-Sn-Pb and Zn-silicate phases are present in the RDS, and this is corroborated by SEM and XRD. Other phases suggested by EXAFS include ZnO, franklinite, Zn-sorbed birnessite and zinc formate. Differences between the XANES and other results suggest that model compounds such as Zn-bearing phyllosilicates and metallic Zn phases may have been missing from the XANES fitting. Long-term low-level exposure to the RDS Zn phases identified may lead to an increased risk of cardiovascular or pulmonary diseases.

In order to assess the role played by sheet silicates in controlling base metal distribution, the mineralogy of the <2 µm fraction of waste material, surface soils, and stream sediments was investigated in the surroundings of a pyrite-chalcopyrite mine area in northern Italy. The results indicate that smectite is very abundant in the <2 µm fraction of the tailings, and it exerts an effective control on the concentrations of Zn, Ni (and Cu). Normal soils and sediments are characterized by interstratified illite-smectite and by lower base metal concentrations. Away from the mine area, smectite decreases in the stream sediments, and chlorite becomes more important in controlling base metal distribution.

Ni, Cr, Cu and Co increase with chlorite and talc, but are depleted in the <2 µm fraction compared to coarser fractions in the stream sediments, because the sand–silt fraction of sediments concentrates ophiolitic fragments, variably enriched in ores. A mechanical dispersion of chlorite is probably the controlling factor. Zinc displays a systematic enrichment in the clay fraction of waste material and in the stream sediments but the main mineral carrier is not identified.

The ZnO/g-C3N4 binary heterostructures were formed by two steps, then the firm connection between ZnO NRs and lamellar g-C3N4 was characterized through powder XRD, FESEM with EDS, TEM, XPS, and Thermogravimetric analysis. Then the gas sensing performances of ZnO/g-C3N4 nanoheterostructures were analyzed systematically by using ethanol as a molecular probe. The results revealed that the fabricated compositive sensor not only exhibited quick response/recovery characteristics in the whole operating temperature (OT) range of 200–300 °C but also got a maximum response of 14.29 toward 100 ppm of ethanol at the optimal OT of only 260 °C. Moreover, such heterostructures also demonstrated good selectivity and superb reproducibility to acetone among all the tested toxic gases, especially higher response and faster response–recovery speeds than the pristine ZnO sensor. The above ZnO/g-C3N4 heterostructures may also supply other novel applications in the aspects of lithium-ion batteries, photocatalysis, optical devices, and so on.

ZnFe2O4 (ZFO) represents a promising anode material for lithium ion batteries, but there is still a lack of deep understanding of the fundamental reduction mechanism associated with this material. In this paper, the complete visualization of reduction/oxidation products irrespective of their crystallinity was achieved experimentally through a compilation of in situ X-ray diffraction, synchrotron based powder diffraction, and ex-situ X-ray absorption fine structure data. Complementary theoretical modelling study further shed light upon the fundamental understanding of the lithiation mechanism, especially at the early stage from ZnFe2O4 up to LixZnFe2O4 (x = 2).

Zinc borate has long been used as a protector for wood products due to its fungicide, insecticide and flame retardant properties. In this initial study, its capacity as a flame retardant when applied to Eucalyptus grandis wood is evaluated; micronized zinc borate, synthesized from zinc oxide and boric acid in our laboratory was used. The methodology used in the study is the use of the Vandersall tunnel, which allowed analyzing parameters such as the flame spread, the carbonization index, the carbonization area and the wood weight loss. The results show a remarkable improvement in these parameters after the application of micronized zinc borate. For the longest fire exposure time, the percentage decrease of each evaluated parameter is, for tangential and radial plane respectively: 31.27-43.00% for flame spread, 36.66-40.86% for carbonization area, 33.01-52.49% for carbonization index and 19.86-57.80% for mass loss.

Methods of obtaining large grain size and high crystallinity in absorber materials play an important role in fabrication of high-performance methylammonium lead iodide (MAPbI3) perovskite solar cells. Here we study the effect of adding small concentrations of Cd2+, Zn2+, and Fe2+salts to the perovskite precursor solution used in the single-step solution fabrication process. Enhanced grain size and crystallinity in MAPbI3 films were obtained by using 0.1% of Cd2+ or Zn2+in the precursor solution. Consequently, solar cells constructed with Cd- and Zn-doped perovskite films show a significant improvement in device performance. These results suggest that the process may be an effective and facile method to fabricate high-efficiency perovskite photovoltaic devices.

A comparison of microstructure, mechanical properties and fracture behavior of Mg–9Gd–3Y–xZn–0.5Zr (x = 0, 0.2, 0.5, 1.0, and 1.5) (wt%) alloys under different thermal treatment conditions was investigated in this study. The results showed that the as-cast alloys were comprised of Mg matrix, eutectic compounds and cuboid-shaped phases. The eutectics were Mg24(Gd, Y)5 in the alloys of Zn content ≤0.2 wt%, while (Mg, Zn)3RE in the other three alloys. Fine lamellar long period stacking ordered structure formed inside of matrix of the as-cast Zn-containing alloys and its quantity increases with raising Zn content. Mg12(Gd, Y)Zn was observed at grain boundary of Mg matrix after solution treatment in the alloys of Zn content ≥0.5 wt%. Peak-aged Mg–9Gd–3Y–0.5Zn–0.5Zr alloy exhibited a desirable combination of strength and elongation with 244 MPa in yield strength, 371 MPa in ultimate tensile strength and 3.8% in EL. Meanwhile, the fracture behavior of the studied alloys was also investigated.