Zn In Solution Research Articles

Zinc glycolate Zn(OCH2CH2O): Synthesis and structure, spectral and optical properties, electronic structure and chemical bonding

This article presents new findings obtained from the study of formation conditions, crystal structure, thermal, spectral, optical properties and electronic band structure of zinc glycolate Zn(OCH2CH2O). This compound was synthesized by heating the solutions of zinc formate Zn(HCOO)2·2H2O in ethylene glycol (A) or in a mixture of ethylene glycol and distilled water (B). The crystal structure of Zn(OCH2CH2O) has been studied using the X-ray powder diffraction method. It is shown that the crystal structure is built via zigzag joining of [Zn4O12C8H16] tetracycles with the tetrahedrally coordinated zinc (ZnO4). Zinc atoms inside the tetracycles and the tetracycles themselves are interconnected with oxygen bridges. Complex anions OCH2CH2O2- are bonded to zinc atoms by chelation. The unit cell parameters of Zn(OCH2CH2O) are as follows: the tetragonal structure, space group I41/a (88−2), Z = 16, a = b = 11.08673(9) Å, c = 11.5902(1) Å, V = 1424.62(2) Å3. The IR and Raman spectra of Zn(OCH2CH2O) correlate fully with the results of structural analysis. Under UV excitation, the luminescence spectra of Zn(OCH2CH2O) samples synthesized following the methods (A) and (B) are characterized by emission maxima at 460 nm (blue luminescence) and 540 nm (yellow-green luminescence), respectively. Yellow-green luminescence is due to the presence of an admixture of zinc oxide nanoparticles of size 10 nm in the sample. The electron density functional method is employed to study the electronic band structure and chemical bonding in Zn(OCH2CH2O). It is shown that the 3dZn orbitals are covalently bonded to 2pO orbitals so that an octagon is formed, where the zinc atoms of four neighboring ZnO4 tetrahedrons are linked through their vertices. The feasibility of synthesizing a layered structure of Zn(OCH2CH2O) is analyzed on the basis of ab initio calculations and Voigt-Reuss-Hill theory.

Exploiting an as-extruded fine-grained Mg-Bi-Mn alloy with strength-ductility synergy via dilute Zn addition

Here, a new Mg-1Bi-1Mn-0.3Zn (BMZ110, wt%) wrought alloy designed by the dilute addition of Zn subjected to an appropriate extrusion processing that showed an excellent strength-ductility synergy at room temperature. The main results included four aspects as follows: 1) With dilute Zn addition, the as-cast BMZ110 alloy was refined into an approximately equiaxed-grained structure, since the solid solution of Zn provided a relatively high growth restriction factor. 2) The as-extruded BMZ110 alloy exhibited the finer average grain size and weaker basal texture intensity than the as-extruded BM11 alloy without Zn. The co-segregation of Bi and Zn solutes into grain boundaries was observed to impede grain growth during extrusion and further weaken texture intensity. Moreover, Zn atoms incorporated into Mg3Bi2 phases by replacing Bi atoms increasing the nucleation rate of Mg3Bi2 phases and refining their sizes. 3) Compared with the as-extruded BM11 alloy, the as-extruded BMZ110 alloy demonstrated the higher yield strength (~ 283.4 MPa), ultimate strength (~ 366.2 MPa) and elongation-to-failure (~ 26%). The size refinement of grains and second phases contributed to an extra strength increments. Grain boundary segregation enhanced grain boundary cohesion not only reducing the number density of grain boundary cracks, but also activating more slip modes and grain rotation for increasing the ductility. 4) The as-extruded BMZ110 alloy had the higher grain growth resistance than the as-extruded BM11 alloy during annealing. Solute segregation offered an effective obstacle to restrict grain boundary migration enlarging the activation energy (~ 112.2 kJ/mol) and further delaying the grain growth. Therefore, this work will be helpful for the development of new high performance low-alloyed Mg-Bi based wrought alloys to achieve extensive applications in industries.

Directional-dependent precipitate microstructure and mechanical properties of tensile and compressive stress-assisted aged Mg-Zn alloys

Aging aided by external elastic stress is of scientific interest and practical importance in improving the precipitation hardening response of magnesium alloys. In this work, fiber textured Mg-6 wt.% Zn alloys were subjected to tensile and compressive stress-assisted aging (TSA and CSA, respectively), in which stress is applied along the extrusion direction. Results reveal that the precipitate microstructure, including shape, size, distribution and even internal defect structures exhibits a stress directional dependence. Aberration-corrected scanning transmission electron microscopy shows that a high number density of Zn solute clusters is produced upon CSA, and relatively fine β1’ precipitates are predominantly formed under TSA. First-principles calculations indicate that the stress direction-dependent solute diffusion ability is the leading cause of such directional-dependent precipitate characteristics. Furthermore, TSA generates a higher yield strength than that of stress-free aging (SFA), owing to the relatively high density of fine β1’ precipitates. Compared with SFA and TSA alloys, the CSA alloy contains massive Zn solute clusters and has higher yield strength and better ductility due to the strong cluster-dislocation interactions without the generation of local high stress concentration at the coherent interface. This work offers further insights into altering the precipitation behavior of Mg alloys by applying external stress field and provides possible solutions to achieve high strength-ductility synergy in Mg alloys.

Structural Strength Analyses for Low Brass Filler Biomaterial with Anti-Trauma Effects in Articular Cartilage Scaffold Design.

The existing harder biomaterial does not protect the tissue cells with blunt-force trauma effects, making it a poor choice for the articular cartilage scaffold design. Despite the traditional mechanical strengths, this study aims to discover alternative structural strengths for the scaffold supports. The metallic filler polymer reinforced method was used to fabricate the test specimen, either low brass (Cu80Zn20) or titanium dioxide filler, with composition weight percentages (wt.%) of 0, 2, 5, 15, and 30 in polyester urethane adhesive. The specimens were investigated for tensile, flexural, field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) tests. The tensile and flexural test results increased with wt.%, but there were higher values for low brass filler specimens. The tensile strength curves were extended to discover an additional tensile strength occurring before 83% wt.%. The higher flexural stress was because of the Cu solvent and Zn solute substituting each other randomly. The FESEM micrograph showed a cubo-octahedron shaped structure that was similar to the AuCu3 structure class. The XRD pattern showed two prominent peaks of 2θ of 42.6° (110) and 49.7° (200) with d-spacings of 1.138 Å and 1.010 Å, respectively, that indicated the typical face-centred cubic superlattice structure with Cu and Zn atoms. Compared to the copper, zinc, and cart brass, the low brass indicated these superlattice structures had ordered–disordered transitional states. As a result, this additional strength was created by the superlattice structure and ordered–disordered transitional states. This innovative strength has the potential to develop into an anti-trauma biomaterial for osteoarthritic patients.

Unraveling the doping preference of zinc ions in sulfoaluminate cement clinker minerals: A study combining experiments and DFT calculations

Combining X-ray diffraction, elemental distribution spectroscopy, and density functional theory simulations, we systematically studied the doping preference of zinc ions in sulfoaluminate cement (SAC) clinker. Our results show that Zn atoms prefer to enter into C4AF while hardly into the other two minerals, C4A3S‾ and C2S. Quantitative analyses of the doping behaviours of Zn in C4AF were also performed with Rietveld refinements. The Zn atoms as solid solute tend to occupy the sites of Fe, which is well supported by the low formation energy, small local structural distortions, and bond order-bond length distribution overlaps between the host and the guest ions. The difference in electron contributions of spatial distributions between Zn–O and Fe–O may be the main reason determining the solid solution of Zn. The deep insights on these fundamental issues should provide an efficient way to improve the solid solution of Zn by increasing the C4AF content, thus should be helpful in guiding the synthesis of SAC clinker by utilizing Zn-bearing solid waste.

Zn(II) porphyrin sensitized (TiO2@Cd-MOF) nanocomposite aerogel as novel photocatalyst for the effective degradation of methyl orange (MO) dye

The highly porous three-dimensional TiO2@Cd-MOF (MOF - Metal-organic framework) nanocomposite aerogels were synthesized through a slightly modified version of the conventional sol-gel method used to synthesize mesoporous TiO2 aerogels. The as-prepared nanocomposite aerogels were further immersed in solutions of Zn(II) porphyrin (ZnPp) to obtain Zn(II) porphyrin-sensitized nanocomposite aerogel (TiO2@Cd-MOF)@ZnPp. The newly synthesized (TiO2@Cd-MOF)@ZnPp materials were used as novel heterogeneous photocatalyst and their photocatalytic performances were evaluated by testing the photodegradation of model pollutant methyl orange (MO) dye under visible-light irradiation. The obtained results showed that the heterogeneous photocatalysts exhibited a superior photocatalytic activity compared with pure aerogel and nanocomposite aerogel towards the degradation of pollutants. The maximum degradation efficiency of 94.1% was obtained for heterogeneous photocatalyst. Further, the results of recycle tests confirmed the good photostability of the photocatalyst. The synergistic effects of the heterostructure, an enhanced optical absorption, and efficient electron injection are the prime factors responsible for the photocatalytic activity improvement of (TiO2@Cd-MOF)@ZnPp photocatalysts.

Local atomic ordering strategy for high strength Mg alloy design by first-principle calculations

In this study, solute X (X = Li, Al, Mn, Zn, Y, Zr, Nd, and Gd) solution strengthening in Mg alloys have been screened by ab initio density functional theory calculations to quantify not only the substitutional stacking-fault configurations but also the solute ordering sequence as a function of local segregation. Interestingly, it has been found that the strengthening effects of single atom addition to a supercell made of 64 atoms can be mostly attributed to lattice distortions (Mn>Nd>Gd>Y>Zn>Al>Zr>Li), while the local ordering arrangements of Mg-X complex actually contribute most to the strengthening when the solute concentration rises. For example, Nd can induce a large local atomic ordering and significantly increase the basal critical-resolved shear stress (CRSS). A linear relationship between solute concentrations and ideal strength, and the quasi-quadratic relationship between solute atomic radii and ideal strength have been observed. Simultaneously, the higher the solute concentration, the higher degree of the solid solution strengthening, resulting in a smaller quasi-quadratic function curve opening. Based on the screening of the chemical (including stacking fault energy and atomic bonds) and strain (lattice distortion energy) energy calculations, we have discovered that the solute strengthening follows the ordering sequence of Nd> Mn> Gd> Y> Zn> Al> Zr> Li. • Local ordering of Mg-X alloys was found by thermodynamic evaluations using DFT. • Both chemical and strain energy contribute to the solute strengthening ordering. • Local ordering configuration in solid solution strengthening guide the alloy by design.

Analysis of the Response Characteristics of Toluene Gas Sensors with a ZnO Nanorod Structure by a Heat Treatment Process.

The sensing characteristics of toluene gas are monitored by fabricating ZnO nanorod structures. ZnO nanostructured sensor materials are produced on a Zn film via an ultrasonic process in a 0.01 M aqueous solution of C6H12N4 and Zn(NO3)2∙6H2O. The response of the sensors subjected to heat treatment in oxygen and nitrogen atmospheres is improved by 20% and 10%, respectively. The improvement is considered to be correlated with the increase in grain size. The relationship between the heat treatment and sensing characteristics is evaluated.

Green and Controllable Preparation of Cu/Zn Alloys Using Combined Electrodeposition and Redox Replacement

This study outlines a novel and sustainable electrodeposition–redox replacement (EDRR) method to produce Cu/Zn alloys using a simulated hydrometallurgical Zn solution containing 200 ppm Cu, 65 g/L Zn, and 10 g/L H2SO4. The results indicate that by tailoring the EDRR parameters, like deposition time, replacement time, and agitation conditions, Cu/Zn alloys with controllable properties including chemical composition, microstructures, colorations, and crystalline phases can be readily obtained. Scanning electron microscopy (SEM) analysis shows that coherent Cu/Zn films grow from separate nanoscale particles produced during the initial EDRR cycles. Furthermore, the corrosion performance of the prepared Cu/Zn films is tunable by changing the crystalline phases through the variation of operating conditions. For example, deposits containing Zn-rich phases (CuZn5, Cu5Zn8) obtained with short redox replacement times without agitation resulted in relatively poor corrosion resistance. In contrast, Cu-rich phases (Cu0.75Zn0.25, Cu0.85Zn0.15) with enhanced corrosion performance were achieved with prolonged redox replacement times and/or the application of magnetic stirring. Unlike traditional electrodeposition, the EDRR method does not involve any complexing agents and the currently underutilized hydrometallurgical solutions were used as potential raw materials. Overall, the study suggests the EDRR method as a promising approach to achieve sustainable manufacturing of Cu/Zn alloys and an improved circular economy of metals.

The effect mechanism of Zn, Ni and Mn solute elements on the WC/Cu-based filler metal interfacial properties: first-principles calculations and experiments

In this work, the first-principles calculation was performed to investigate the effect mechanism of Zn, Ni and Mn solute elements on the WC/Cu-based filler metal interfacial properties, and the CuZnNiMn filler metal was designed, the diffusion behavior of interface elements was verified by experiments. Firstly, Zn, Ni and Mn element doping WC/Cu interface models were established respectively. The effect natures of alloying elements on the interfacial properties were explored by adhesive strength and interfacial electronic structure. The results show that Zn element slightly aggregate into the Cu matrix interior after full relaxation, which has little effect on the interface structure, but it can lower the melting point and optimize the properties of Cu-based filler metals. Ni, Mn elements tend to segregate toward the interface and form strong covalent bonds and metallic bonds with W atoms, which can significantly improve the interfacial bonding strength of WC/Cu. The Energy Dispersive Spectroscopy (EDS) analysis of the WC/CuZnNiMn interface region proves that the diffusion effect of Zn in the interface is not obvious, while the Ni and Mn elements strongly diffuse into the WC particle, which has a positive effect on the metallurgical bonding of the brazed joint.

Effect of Zn interlayer on friction stir butt welding of A1100 and SUS316L stainless steel

The effect of Zn interlayer on the microstructure and mechanical properties of dissimilar A1100 and SUS316L friction stir welded (FSW) butt joints was investigated. The results showed that Zn could improve the joint’s tensile strength. However, a complete dissolution of the Zn interlayer was necessary to achieve a sound joint. During the FSW process, the stirring action of the tool dispersed the Zn into the A1100 matrix forming a solid solution of Zn. A direct relationship was found between the tool rotational speed and the Zn dissolution rate. Also, the addition of Zn inhibited the Al–Fe IMCs growth, which played a positive role in the obtained tensile strength.

Detailed experimental investigation of the highly active corrosion inhibitive green molecules based on zinc cations/Nepeta Pogonosperma extract and toward the corrosion mitigation of mild steel in the saline solution

This work has been focused on the synergistic corrosion retardation performance (CRP) of the Nepeta pogonosperma leaves from the Lamiaceae family, which is locally called Larzeh (LA), and zinc cations (Zn2+) over the mild steel plates (MSPs) in the 3.5 wt% sodium chloride (NaCl) solution (3.5%-SCS). Different concentrations of the LA extract and Zn2+ were dissolved in the saline solutions to prepare the solution systems. The electrochemical evaluation of MSPs submerged in the solution systems was performed using EIS and PP tests. Among various ratios of LA:Zn, the 300:700 ppm LA:Zn solution illustrated the highest CRP (119.3 kΩ cm2) and efficiency (93.7%) after 12 h and was selected as the optimal solution, while the CRP values of the blank, 700:300, and 500:500 ppm LA:Zn were 1.59, 57.1, and 38.4 kΩ cm2, respectively. In the presence of 700:300, 500:500, and 300:700 ppm LA:Zn, Icorr decreased from 3.78 μA cm−2 for the blank solution to 0.372, 0.345, and 0.236 μA cm−2, respectively. WCA results proved that a more hydrophobic layer (≈55°) was formed on the MSP with 300:700 ppm LA:Zn compared to those with 700:300 (≈33°) and 500:500 (≈24°) ppm LA:Zn. The surface characterization of MSPs submerged in 300:700 ppm LA:Zn solution was carried out using FT-IR, Raman, and GIXRD analyses. Surface characterization results proved the construction of a thicker multilayer zinc-centered organic inhibitive layer by the 300:700 ppm LA:Zn extract over the MSP surface compared to other MSPs with maximum amounts of O (7.85 wt%), C (6.55 wt%), N (1.78 wt%), and Zn (20.57 wt%) elements.

Luminescence Properties of Nano Zinc Oxide Doped with Al(III) Ions Obtained in Microwave-Assisted Hydrothermal Synthesis.

The hydrothermal method of obtaining nano zinc oxide doped with different contents of aluminum ions (III) was presented and discussed in this paper. Aqueous solution of Zn(NO3)2*6H2O and Al(NO3)3*9H2O salts mixture were used as the synthesis precursor. In order to reduce the process time all reactions were performed in a microwave reactor. The influence of process parameters and the content of impurity ions on the properties of synthesized nano zinc oxide were analyzed. In addition to zinc oxide doped with Al(III) ions, an additional spinel phase (ZnAl2O4) was obtained. The luminescent properties of nano zinc oxide as a function of the dopant ions were also discussed. Based on the luminescence measurements results, it was found that the luminescence intensity decreases with the increasing dopant content. The obtained materials are aimed to be implemented as luminescent materials in optoelectronic and sensors.

Segregation-driven exceptional twin-boundary strengthening in lean Mg–Zn–Ca alloys

Twinning-mediated plasticity in hexagonal close-packed crystal structures offers great potential for achieving lean Mg-based alloys with high strength and extended ductility. Micropillars from a lean MgZn1 Ca0.3 (ZX10, in wt%) alloy and pure Mg, each comprising one or more pre-existing {101¯2}<1¯011> extension twin boundaries and a parent orientation with its c-axis perpendicular to the loading direction, were subjected to in situ micropillar compression. By means of correlative characterization using transmission electron backscattered diffraction, transmission electron microscopy and nanoscale energy-dispersive X-ray spectroscopy, we assesed the effects of Zn and Ca solutes on micropillar deformation and on the response of pre-existing twin-boundaries to applied stress. In ZX10, both Zn and Ca solutes periodically segregate at the pre-existing extension twin boundaries, giving rise to a strengthening increment by about 300% compared to pure Mg, along with ductility enhancement. Due to segregation, the twin boundaries remain immobile throughout the deformation process, playing a critical role both in non-basal slip and twin-nucleation events. The former is facilitated by the formation of stable I1 stacking faults, while the latter is stimulated by active <c+a> slip across the pinned twin interface. In contrast, the pure Mg micropillars respond by massive twin growth followed by higher-order twinning events and profuse basal slip. In the absence of non-basal slip, pure Mg exhibits an earlier onset to failure due to shear incompatibility at the twin interface. The findings provide new insights into the role of solute Zn and Ca in stabilizing twinned microstructures for achieving synergistic strength-ductility enhancement in lean Mg alloys.

Facile Construction of Cu/ZnO Heterojunctions for Enhanced Photocatalytic Performance

The design and construction of semiconductor–metal heterojunctions are being considered to be an effective way to overcome the limited visible-light absorption of semiconductors. Herein, a facile and scale approach is reported for the first time to synthesize Cu/ZnO heterojunctions by one-step galvanic replacement between Zn and cuprous solution reaction. Two kinds of morphologies Cu/ZnO heterojunctions could be obtained by changing cuprous salt anion such as Br−, Cl− and I−. A flower-like Cu/ZnO heterostructured is chosen as a representative to demonstrate the facility and enhanced photocatalytic performance toward Rhodamine B degradation under visible-light irradiation. Results showed flower-like Cu/ZnO heterojunctions have higher photocatalytic performance than the other two morphologies. The galvanic replacement growth mechanism of Cu/ZnO heterojunctions was also further investigated. It is found that Cu/ZnO heterojunctions formed from Zn and Cu2O at an acid solution and room condition. This work indicates that galvanic replacement reaction at room temperature is an excellent technique to grow Cu/ZnO heterojunctions and demonstrates that the hole and electron transfer between Cu and ZnO can efficiently enhance their photocatalytic performance. This general method can also be further explored to guide the design of metal/metal oxide heterostructured on other substrates, such as Zn, Ni and Cu foils.

Selective adsorption and separation of Cu(II) from Zn solution by CU resin

Selective adsorption and separation of Cu(II) from Zn solution by CU resin

Chitosan/ZIF‐8 Composite Beads Fabricated by In Situ Growth of MOFs Crystals on Chitosan Beads for CO2 Adsorption

AbstractCO2 responsive polymer chitosan is introduced to fabricate polymer/MOFs composite materials used to explore CO2 adsorption and recyclability. Chitosan beads (CBs) are successively immersed in the solution of Zn2+ and the solution of 2‐methylimidazole to fabricate chitosan/ZIF‐8 composite beads (CBsZx) by in situ growth of ZIF‐8 crystal on chitosan beads. CBsZx are characterized by powder XRD, FT‐IR, SEM, TEM, TGA and BET. The morphology, size and distribution of the ZIF‐8 crystals on CBsZx are tuned by adjusting the concentration of Zn2+ in the soaking solution. The coordination of the free amino groups on chitosan skeleton with Zn2+ and self‐emulsifying properties of chitosan have played a key role in situ growth of the ZIF‐8 crystals on chitosan beads. Additionally, the adsorption capacity and recyclability of CBsZx for CO2 has been evaluated. Compared with the pure ZIF‐8 crystals, the adsorption capacity of CBsZx for CO2 is significantly enhanced by 90 %. The kinetic models indicate that the adsorption of CBsZx for CO2 belongs to physical adsorption, when the ZIF‐8 crystals on chitosan beads have the regular shape and size. Moreover, the adsorption capacity of CBsZx for CO2 is remained more than 80 % after 3 recycling.

Seed Priming and Foliar Application with Nitrogen and Zinc Improve Seedling Growth, Yield, and Zinc Accumulation in Rice

Improving grain yield and zinc (Zn) concentration yields a double benefit for farmers and consumers, especially when accomplished through the common practice of nitrogen (N) and Zn application. The objective of this study was to evaluate responses of a modern improved rice variety (SPT1) to Zn and N fertilizer management of seed germination, seedling growth, yield, and grain Zn accumulation. A preliminary laboratory study was conducted by priming seeds with variation of N and Zn solutions, consisting of (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 0% urea + 0.07% ZnSO4 (N0Zn+), (3) 0.05% urea + 0.07% ZnSO4 (N0.05Zn+), (4) 0.10% urea + 0.07% ZnSO4 (N0.10Zn+), (5) 0.15% urea + 0.07% ZnSO4 (N0.15Zn+), (6) 0.20% urea + 0.07% ZnSO4 (N0.20Zn+), and (7) 0.25% urea + 0.07% ZnSO4 (N0.25Zn+). Priming seeds with N0.15Zn+ led to a higher germination rate and growth performance. Seedling Zn concentration increased linearly along with the dry weights of root and coleoptile during germination. A second experiment in the field included priming the seed with (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 0.15% urea + 0% ZnSO4 (N+Zn0), (3) 0% urea + 0.07% ZnSO4 (N0Zn+), and (4) 0.15% urea + 0.07% ZnSO4 (N+Zn+); this experiment showed that simultaneous priming of seeds with 0.15% urea and 0.07% ZnSO4 (N+Zn+) resulted in the highest coleoptile length and seedling dry weight. The highest seedling Zn concentration was observed when priming seeds with N0Zn+ followed by N+Zn+, but the effect disappeared at the later growth stages. A third experiment in the field was conducted by foliar application with four different treatments of (1) 0% urea + 0% ZnSO4 (N0Zn0), (2) 1% urea + 0.5% ZnSO4 (N+Zn0), (3) 0% urea + 0.5% ZnSO4 (N0Zn+), and (4) 1% urea + 0.5% ZnSO4 (N+Zn+). The highest grain yield increases were achieved by foliar application of N+Zn0 (28.5%) and foliar application of N+Zn+ (32.5%), as compared with the control (N0Zn0). Grain Zn concentration was the highest under foliar application of N+Zn+, with a 37.9% increase compared with N0Zn0. This study confirmed that seedling growth performance can be enhanced by initially priming seeds with N and Zn solution, while grain yield and Zn concentration can be improved by foliar application of N and Zn fertilizer. The information would be useful for the appropriate combined application of Zn and N fertilizers in the practical field to improve grain yield and Zn accumulation as well as Zn nutrition among humans with rice-based diets. The result should be extended to a wider range of rice varieties under suitable management of N and Zn fertilizer.

Microwave-Assisted Green Synthesis of Pure and Mn-Doped ZnO Nanocomposites: In Vitro Antibacterial Assay and Photodegradation of Methylene Blue

This paper describes the eco-friendly microwave-assisted green synthesis of pure and manganese-doped zinc oxide nanocomposites using ethanolic solution of castor oil as a reductant and capping agent. Solutions of Zn2+ and Mn2+ ions were mixed in fixed ratios to obtain 0%, 1%, 2.5%, 5%, and 7% pure and Mn-doped ZnO nanomaterials. The obtained nanomaterials were characterized by powder XRD, FT-IR spectroscopy, scanning electron microscopy, and EDX analyses. Powder XRD furnished characteristic fragmentation patterns for the confirmation of the synthesized materials and was also used to estimate the size of the synthesized nanoparticles by Scherrer’s equation. Diffraction patterns were characteristic of wurtzite structure and of the size in the range of 6.5, 5.6, 5.2, 5.1, and 4.3 nm for pure and Mn-doped ZnO nanocomposites. UV-visible spectra displayed maximum absorbance at 340 nm, and manganese doping caused a red shift. FT-IR spectra confirmed that the formation of zinc oxide nanoparticles as Zn─O appeared at below 700 cm−1 as well as the presence of organic moieties of the castor oil acting as stabilizing agents. Scanning electron micrographs (SEM) revealed all the synthesized materials were spherical in shape with some aggregation and polydispersity, and in the Energy-dispersive X-ray spectroscopy (EDX), specific peaks with characteristic patterns were seen for Zn, O, and Mn. A TEM micrograph displayed the hexagonal wurtzite structure of nanoparticles with average size less than 50 nm. Photocatalytic degradation of methylene blue was checked in the presence of sunlight and in darkness. Interestingly, samples placed under the solar radiation exhibited significant results only with the catalyst; all the samples used without the catalyst showed negligible degradation effects, and even the samples placed in the dark containing catalysts also displayed a negative effect. A mechanism for this significant activity is also proposed. In vitro the antibacterial potential was studied against two pathogenic strains, i.e., Streptococcus aureus and Escherichia coli; interestingly activity kept on increasing with the increasing manganese content. Overall, all the samples presented comparable activity to ciprofloxacin.

Self-Assembly of Oriented Antibody-Decorated Metal-Organic Framework Nanocrystals for Active-Targeting Applications.

Antibody (Ab)-targeted nanoparticles are becoming increasingly important for precision medicine. By controlling the Ab orientation, targeting properties can be enhanced; however, to afford such an ordered configuration, cumbersome chemical functionalization protocols are usually required. This aspect limits the progress of Abs-nanoparticles toward nanomedicine translation. Herein, a novel one-step synthesis of oriented monoclonal Ab-decorated metal-organic framework (MOF) nanocrystals is presented. The crystallization of a zinc-based MOF, Zn2 (mIM)2 (CO3 ), from a solution of Zn2+ and 2-methylimidazole (mIM), is triggered by the fragment crystallizable (Fc) region of the Ab. This selective growth yields biocomposites with oriented Abs on the MOF nanocrystals (MOF*Ab): the Fc regions are partially inserted within the MOF surface and the antibody-binding regions protrude from the MOF surface toward the target. This ordered configuration imparts antibody-antigen recognition properties to the biocomposite and shows preserved target binding when compared to the parental antibodies. Next, the biosensing performance of the system is tested by loading MOF*Ab with luminescent quantum dots (QD). The targeting efficiency of the QD-containing MOF*Ab is again, fully preserved. The present work represents a simple self-assembly approach for the fabrication of antibody-decorated MOF nanocrystals with broad potential for sensing, diagnostic imaging, and targeted drug delivery.