Zn Nanoparticles Research Articles

Mixed transition-metal oxides@carbon core-shell nanostructures derived from heterometallic clusters for enhanced lithium storage

Multicomponent binary metal oxide-involved hybrid structures with unique physicochemical properties have received extensive attention due to their fascinating electrochemical performance. Herein, a flexible strategy, which involves the preparation of dual-functional heterometallic Fe2M clusters and their subsequent sintering treatment, is developed to engineer novel 3D hierarchical porous structures assembled with MFe2O4 (M = Co, Mn, Ni and Zn) nanoparticles confined within carbon outer shell (denoted as MFe2O4@C HPSs). In this intriguing construction, it can be observed that MFe2O4@C HPSs comprised of carbon coated secondary MFe2O4 nanoparticles with an interconnected carbon network. The as-prepared MFe2O4@C HPSs possess combined advantages of high capacity of MFe2O4 and high conductivity of carbon. As expected, the MFe2O4@C HPSs offer a high reversible capacity, high cycling stability and superior rate performance. The interconnected conductive carbon shells facilitates fast ion and electron transport and accommodates the mechanical strain. In addition, nanosized MFe2O4 particles, which shorten the ion-transport path and provide extra electroactive sites, also improve the reaction kinetics. Moreover, these MFe2O4@C HPSs exhibit good structural integrity during repeated charging and discharging. The research perspective and strategy reported here are highly versatile and shed new light on the synthesis of other advanced electrode for various applications.

ZIF-L Derived Bimetallic N-Doped Porous Carbon-Prussian Blue Composite as Efficient Catechol Electrochemical Sensor

The development of effective and accurate catechol (CC) electrochemical sensors is critical for environment and life health perspectives. A facile pyrolysis of 2D bimetallic (Zn/Co) zeolitic imidazolate framework (Zn/Co-ZIF-L) was employed to prepare Zn and Co nanoparticles encapsulated in N-doped porous carbon (Zn/Co@NPC). Prussian blue (PB) was synthesized in situ via the co-precipitation of ferricyanide ([Fe(CN)6]3−) and iron (II) ion originated from the reduction of Fe3+ by Zn/Co@NPC and then served as the main active substance of CC detection. The morphology and composition of the final composite Zn/Co@NPC-PB were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). The Zn/Co@NPC-PB modified glass carbon electrode (GCE) exhibits two concentration linear ranges of 4.13 μM − 1.08 mM (R2 = 0.999) and 1.08 mM−11.82 mM (R2 = 0.999) for CC electrochemical detection with a limit of detection 1.05 μM (S/N = 3). At the same time, the Zn/Co@NPC-PB/GCE shows great selectivity to electrochemical oxidation behavior of CC in presence of 20 folds dihydroxybenzene interferents such as hydroquinone and resorcinol. Furthermore, it showed a long-term stability and near 100% recovery for the detection of a real sample in Yellow River water.

Effect of the Nanostructured Zn/Cu Electrocatalyst Morphology on the Electrochemical Reduction of CO2 to Value-Added Chemicals.

Zn/Cu electrocatalysts were synthesized by the electrodeposition method with various bath compositions and deposition times. X-ray diffraction results confirmed the presence of (101) and (002) lattice structures for all the deposited Zn nanoparticles. However, a bulky (hexagonal) structure with particle size in the range of 1–10 μm was obtained from a high-Zn-concentration bath, whereas a fern-like dendritic structure was produced using a low Zn concentration. A larger particle size of Zn dendrites could also be obtained when Cu2+ ions were added to the high-Zn-concentration bath. The catalysts were tested in the electrochemical reduction of CO2 (CO2RR) using an H-cell type reactor under ambient conditions. Despite the different sizes/shapes, the CO2RR products obtained on the nanostructured Zn catalysts depended largely on their morphologies. All the dendritic structures led to high CO production rates, while the bulky Zn structure produced formate as the major product, with limited amounts of gaseous CO and H2. The highest CO/H2 production rate ratio of 4.7 and a stable CO production rate of 3.55 μmol/min were obtained over the dendritic structure of the Zn/Cu–Na200 catalyst at −1.6 V vs. Ag/AgCl during 4 h CO2RR. The dissolution and re-deposition of Zn nanoparticles occurred but did not affect the activity and selectivity in the CO2RR of the electrodeposited Zn catalysts. The present results show the possibilities to enhance the activity and to control the selectivity of CO2RR products on nanostructured Zn catalysts.

Microwave-assisted combustion synthesis of soft ferromagnetic spinel MFe2O4 (M = Ni, Mg, Zn) nanoparticles using Citrus limon fruit extract as a fuel

Microwave-assisted combustion synthesis of soft ferromagnetic spinel MFe2O4 (M = Ni, Mg, Zn) nanoparticles using Citrus limon fruit extract as a fuel

Nano-metals forming bacteria in Egypt. I. Synthesis, characterization and effect on some phytopathogenic bacteria in vitro

Bacterial metal reducers were isolated from water samples collected from harsh condition locations in Egypt. Four selected isolates were identified as Enterococcus thailandicus, Pseudomonas putida, Marinobacter hydrocarbonoclasticus, and P. geniculata for Copper (Cu), Iron (Fe), Cobalt (Co) and Zinc (Zn) Nanoparticles (NPs) production sequentially. Nitrate reductase enzyme was assayed for bacterial isolates which demonstrated that P. putida, and M. hydrocarbonoclasticus have the maximum enzyme production. The produced NPs were characterized by using XRD, TEM, UV–VIS spectroscopy. Magnetic properties for all selected metals NPs were measured using Vibrating Sample Magnetometer (VSM) and demonstrated that FeNPs recorded the highest magnetization value. The antibacterial activity of selected metals NPs was tested against some phytopathogenic bacteria causing the following diseases: soft rot (Pectobacterium carotovorum, Enterobacter cloacae), blackleg (Pectobacterium atrosepticum and Dickeya solani), brown rot (Ralstonia solanacearum), fire blight (Erwinia amylovora) and crown gall (Agrobacterium tumefaciens). All metals NPs showed an antagonistic effect against the tested isolates, particularly, FeNPs showed the highest antibacterial activity followed by CuNPs, and ZnNPs. Due to the small size, high reactivity, and large surface area of biologically synthesized NPs, they are used as a good disinfector, and can be considered as a new and alternative approach to traditional disease management methods.

Synthesis of Metallic Zinc Nanoparticles by Reduction of Zinc Ions in Protonic Solvent

Simple and low environmental impact methods for producing chemically-stable nanoparticles of metallic zinc (Zn) are asked to be developed, because metallic Zn nanoparticles are easily oxidized in air, and organic solvents, which can be used for the fabrication of metallic Zn particles, give a great environmental impact. The present work focuses on the chemical reaction in protonic solvents containing aqueous solvents, of which the use will give a smaller environmental load, and proposes a method for producing metallic Zn nanoparticles by reduction of Zn ions in the protonic solvent. Two kinds of hydrophilic solvents were examined: water and ethylene glycol (EG). The use of water and EG as the solvents produced Zn oxide. Though the addition of aluminum salt to EG also produced Zn oxide, the crystallinity of Zn oxide was lower than that for with no addition of aluminum salt. In the case of the aluminum salt addition, nanoparticles with a size of 27. 5±13.3 nm were fabricated, and not only bonds of Zn-O-Zn and Zn-OH but also a bond of Zn-Zn were confirmed to be formed, which indicated the production of low crystallinity metallic Zn nanoparticles.

Recent Advances in Synthesis and Applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) Nanoparticles.

In the last decade, research on the synthesis and characterization of nanosized ferrites has highly increased and a wide range of new applications for these materials have been identified. The ability to tailor the structure, chemical, optical, magnetic, and electrical properties of ferrites by selecting the synthesis parameters further enhanced their widespread use. The paper reviews the synthesis methods and applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanoparticles, with emphasis on the advantages and disadvantages of each synthesis route and main applications. Along with the conventional methods like sol-gel, thermal decomposition, combustion, co-precipitation, hydrothermal, and solid-state synthesis, several unconventional methods, like sonochemical, microwave assisted combustion, spray pyrolysis, spray drying, laser pyrolysis, microemulsion, reverse micelle, and biosynthesis, are also presented. MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanosized ferrites present good magnetic (high coercivity, high anisotropy, high Curie temperature, moderate saturation magnetization), electrical (high electrical resistance, low eddy current losses), mechanical (significant mechanical hardness), and chemical (chemical stability, rich redox chemistry) properties that make them suitable for potential applications in the field of magnetic and dielectric materials, photoluminescence, catalysis, photocatalysis, water decontamination, pigments, corrosion protection, sensors, antimicrobial agents, and biomedicine.

Efficiency of foliar application of zinc oxide nanoparticles versus zinc nitrate complexed with chitosan on nitrogen assimilation, photosynthetic activity, and production of green beans (Phaseolus vulgaris L.)

The individual application of ZnO nanoparticles and chitosan improve the growth and production of crops, compared to conventional fertilizers, their effectiveness is higher, and the doses can be reduced. However, there is little information regarding foliar application of ZnO nanoparticles complexed with chitosan and its effect on crop physiology. Therefore, the aim of the present study was to evaluate the efficiency of foliar application of zinc oxide nanoparticles versus zinc nitrate complexed with chitosan on the assimilation of nitrogen, photosynthetic activity, and production of green bean cv. Strike. Two sources of zinc were foliar-applied: zinc nanoparticles and zinc nitrate at doses of 0, 25, 50, and 100 ppm with and without chitosan. The results obtained indicate that the foliar application of Zn nanoparticles at 25 ppm and zinc nitrate at 50 ppm were the most efficient doses in favoring biomass accumulation and production. The addition of chitosan favored the biomass, production, and the parameters related to photosynthesis, especially when combined with zinc nitrate while the combination with ZnO nanoparticles presented a possible chelation of the nanoparticles, delaying the release of Zn. Finally, the best nanoparticle treatment was ZnO (25 ppm), which had similar results to the 50 ppm NZN treatment. This indicates that ZnO nanoparticles can reduce the amount of fertilizer to be used without affecting crop yield, so they could be used as nanofertilizers to maximize the productivity of agriculture crops. Finally, this indicates that more in-depth studies are required to know the physicochemical properties of ZnO nanoparticles complexed with chitosan and its effect on the physiology and biochemistry of plants.

Synergistic effect of lithiophilic Zn nanoparticles and N-doping for stable Li metal anodes

Li metal is the most ideal anode material for next-generation high energy lithium-ion batteries. The uncontrollable growth of Li dendrites, however, hinders its practical application. Herein, we propose the adoption of Zn nanoparticles uniformly embedded in N-doped carbon polyhedra homogeneously built on carbon cloth (Zn@NC@CC) to prevent the formation of Li dendrites. Based on theoretical calculation and experimental observation, lithiophilic Zn nanoparticles and N-doping inside of the as-synthesized Zn@NC play a synergistic role in enhancing the adsorption capacity with Li, thus resulting in uniform Li deposition and complete suppression of Li dendrites. Moreover, the porous N-doped carbon polyhedras uniformly distributed on carbon cloth effectively relieves the volume change of Li upon repeated Li stripping/plating process, which contributes to preserving the structural integrity of the whole electrode and hence enhancing its long-term cycling stability. Benefiting from these synergistic effects, the Li-Zn@NC@CC electrode delivers a prolonged lifespan of over 1200 h at 1 mA cm−2 with an areal capacity of 1 mA h cm−2 in symmetric cells and high Coulombic efficiencies of 95.4% under an ultrahigh capacity of 12 mA h cm−2. Remarkably, Li-Zn@NC@CC//LiFePO4 full cells deliver a high reversible capacity of 110.2 mA h g−1 at 1C over 200 cycles.

X-Ray Fluorescence of Copper, Nickle and Zinc Nanoparticles in Motor Oil Prepared by Laser Treatment

This paper represents an attempt to link different techniques such as laser and X-ray fluorescence (XRF). Where we used the laser in preparation and used X-rays to diagnose and analyze for non-traditional samples. The experimental procedure of the LSP is done by using a convergent lens to deliver 600 mJ (1064 nm) of energy and 10 ns laser pulse produced by Q-switched Nd:YAG laser of 1.5 mm spot size in diameter. Doubled distilled deionized water (DDDW) of 3 mm depth is used as transparent confining layer. X-Ray fluorescence technique used to analyze and determine the concentration of different nanoparticles suspended in motor oil. The results showed the accuracy in XRF measurements. the results of the motor oil analysis for Cu, Ni and Zn were 0.1225, 0.0480 and 0.000 weight percent respectively. Maximum relative error between actual measurements and XRF measurements were 6.5%, 10% and 12.5 for Cu, Ni and Zn nanoparticles respectively. The best percentage of suspension is 0.01 wt.%.

A Systematic Review of Biosynthesized Metallic Nanoparticles as a Promising Anti-Cancer-Strategy.

Simple SummaryCancer is one of the major public health burdens in the world. To date, various conventional cancer therapies have been used, but these therapies are less effective and have severe side effects. Currently, in order to find a better cure for cancer, researchers have tried to explore new approaches with minimal toxicity and fewer side effects. In recent years, nanotechnology has been widely used in diseases management and holds a promising future in curing complex incurable diseases, in particular cancer. Biosynthesized metallic nanoparticles are eco-friendly and biocompatible, and can be used in cancer diagnostics, novel treatments, and drug delivery systems. This review gives an overview of the recent advancements in the biosynthesis of metallic nanoparticles (silver (Ag), gold (Au), zinc (Zn) and copper (Cu)) and their possible anti-cancer activities, with particular emphasis on the mechanisms of action, and future research prospects of nano-therapeutics are also discussed.Cancer is one of the foremost causes of death worldwide. Cancer develops because of mutation in genes that regulate normal cell cycle and cell division, thereby resulting in uncontrolled division and proliferation of cells. Various drugs have been used to treat cancer thus far; however, conventional chemotherapeutic drugs have lower bioavailability, rapid renal clearance, unequal delivery, and severe side effects. In the recent years, nanotechnology has flourished rapidly and has a multitude of applications in the biomedical field. Bio-mediated nanoparticles (NPs) are cost effective, safe, and biocompatible and have got substantial attention from researchers around the globe. Due to their safe profile and fewer side effects, these nanoscale materials offer a promising cure for cancer. Currently, various metallic NPs have been designed to cure or diagnose cancer; among these, silver (Ag), gold (Au), zinc (Zn) and copper (Cu) are the leading anti-cancer NPs. The anticancer potential of these NPs is attributed to the production of reactive oxygen species (ROS) in cellular compartments that eventually leads to activation of autophagic, apoptotic and necrotic death pathways. In this review, we summarized the recent advancements in the biosynthesis of Ag, Au, Zn and Cu NPs with emphasis on their mechanism of action. Moreover, nanotoxicity, as well as the future prospects and opportunities of nano-therapeutics, are also highlighted.

Nanospeciation of metals and metalloids in volcanic ash using single particle inductively coupled plasma mass spectrometry

Volcanic activity is one of the main sources of natural nanoparticles. It has been found earlier that the concentration of toxic metals/metalloids in nanoparticles of volcanic ash may be one or two orders of magnitude higher than in bulk sample. However, fate and behavior of toxic metals/metalloids depend on the type of their binding to nanoparticles. Hence, element species adsorbed onto pyroclastic nanoparticles and individual nanophases of metal/metalloid oxides or salts should be distinguished. For the first time, the single particle inductively coupled plasma mass spectrometry has been applied to the nanospeciation of volcanic particles. Ashes of four volcanoes of Kamchatka (Russia) were under study. Nanoparticles were separated from bulk ash samples using coiled-tube field-flow fractionation. It has been shown that the nanospeciation of Ni, Zn, Ag, Cd, Tl, As, Pb, Bi, Te, and Hg is dependent on element and volcano. In most cases these elements can be found both as species absorbed onto pyroclastic nanoparticles and as individual nanophases. The ratios of individual nanophases and adsorbed species vary with the sample. In nanoparticles of Tolbachik volcano ash, Ni, Zn, Tl, and Hg are present only as individual nanophases, while Bi, As, Pb, Ag, Cd, and Te are found both as adsorbed species and individual nanophases. The results obtained open a new door into study on the chemical composition of volcanic ash nanoparticles and their fate in the environment.

A new microfiltration membrane with three-dimensional reticular architecture for Nano-pollutants removal from wastewater

This research provides a new insight into designing next-generation filtration materials for Nano-pollutants removal from wastewater, and potentially for gas/solid or liquid/solid separation in corrosive environment. Considering the high corrosion and oxidation resistance, Ti–40Al–10Nb–10Cr porous alloy was prepared by powder metallurgy and used as a mechanical support with a pore size of around 10 ​μm. Subsequently, metallic Zn nanoparticles was coated on the Ti–40Al–10Nb–10Cr porous framework by means of chemical vapor deposition, obtaining a novel microfiltration membrane with three-dimensional reticular architecture. Furthermore, the influence of Zn coating on surface morphology, pore feature, and filtration capability of Ti–40Al–10Nb–10Cr porous alloy was investigated. It is of note that the as-prepared microfiltration membrane exhibits an excellent Nano-pollutants filtration efficiency of greater than 99.989% from wastewater. Most importantly, such a three-dimensional reticular architecture provides excellent structural stability, allowing the reutilization of the microfiltration membrane for at least 200 filtration cycles of wastewater treatment.

Zinc Affects Cholesterol Oxidation Products and Fatty Acids Composition in Rats' Serum.

The purpose of this work was to evaluate the effect of the nanosized or microsized zinc (Zn) particles on fatty acid profile, enzyme activity and the level of cholesterol, squalene and oxysterols in rats with breast cancer. Rats (female, n = 24) were divided into the following groups: control, and two test groups, whose diets were enriched with either Zn microparticles (342 nm) or Zn nanoparticles (99 nm). All rats were treated twice with the carcinogenic agent; 7,12-dimethylbenz[a]anthracene. In rats whose diet was enriched with zinc (especially in the form of nanoparticles), the number and sizes of tumors were lower. Diet supplementation also significantly reduced the cholesterol (p = 0.027) and COPs (cholesterol oxidation products) levels (p = 0.011) in rats serum. Enriching the diet with Zn microparticles decreased the Δ6-desaturase activity (p < 0.001). Zn influences fatty acids’ profile in rats’ serum as well as inhibiting desaturating enzymes. A reduced amount of pro-inflammatory arachidonic acid derivatives may be the expected effect.

Oxide-derived Cu-Zn nanoparticles supported on N-doped graphene for electrochemical reduction of CO2 to ethanol

The oxide-derived Cu and Zn nanoparticles (prepared by co-precipitation method) supported on N-doped graphene (CuZnx/NGN) were prepared and ZnO loading was optimized for efficient electrochemical CO2 reduction (ECR) to multi-carbon products. The ECR experiments were performed in aqueous 0.1 M KHCO3 electrolyte at ambient pressure. Results suggest that the Faradaic efficiency (FE) for multicarbon products could be tuned by varying the loading of Zn in the CuZnx/NGN. The catalyst with 20 wt% ZnO loading (CuZn20/NGN) gives the highest FE of 34.25% for ethanol production and 12.38% for N-propanol at −0.8 V (vs. RHE) with the total current density of 3.95 mA cm−2. The CuZn20/NGN electrode shows long term stability of at least 24 h at optimized conditions. It is suggested that CO generated at the reduced ZnO nanoparticles increases the local surface coverage of *CO on the reduced CuO, which improves the C-C coupling rate, facilitating the multi-carbon production (i.e. ethanol).

Fluorinated Interface Layer with Embedded Zinc Nanoparticles for Stable Lithium-Metal Anodes.

Lithium-metal batteries are promising candidates for the next-generation energy storage devices. However, notorious dendrite growth and an unstable interface between Li and electrolytes severely hamper the practical implantation of Li-metal anodes. Here, a robust solid electrolyte interphase (SEI) layer with flexible organic components on the top and plentiful LiF together with lithiophilic Zn nanoparticles on the bottom is constructed on Li metal based on the spray quenching method. The fluorinated interface layer exhibits remarkable stability to shield Li from the aggressive electrolyte and restrain dendrite growth. Accordingly, the modified Li electrode delivers a stable cycling for over 400 cycles at 3 mA cm-2 in symmetric cells. An improved capacity retention is also achieved in a full cell with a LiFePO4 cathode. This novel design of the artificial SEI layer offers rational guidance for the further development of high-energy-density lithium-metal batteries.

Biomedical response under visible-light irradiation promoted by new hydrothermally synthesized SiO2-Zn@Fe2O3 nanofibers

In the presence of Fe3O4 nano-fibers, we prepared SiO2-Zn@Fe2O3 hybrid Nano-fibers through a novel and simple one-pot redox reaction between ZnSO4 & SiO2. The Fe3O4 exterior nano-fibers would be homogenously covered by SiO2 coating to arrange a distinctive core-shell construction and then Zn nanoparticles are intercalated in the covering of SiO2. The synthesized nanofibers were tested for photodegradation of methylene blue (MB). The result showed that 99 % MB was degraded in 60 min. Furthermore, the antibacterial potential of SiO2-Zn@Fe2O3 nanofibers was tested against E. coli and S. aureus bacteria both in light and dark. The impact of different analysis such as Reactive oxygen species (ROS) analysis, irradiation effect on bacterial inhibition, concentration effect of SiO2-Zn@Fe2O3 nanofibers and reduction of DPPH studied. The findings clearly demonstrate that ROS is produced in the presence of SiO2-Zn@Fe2O3 nanofibers in bacterial cells and is responsible for their inhibition. Findings have shown that synthesized nanostructures can also increase the stability of DPPH radicals with increasing concentrations of nanomaterials, making them a strong candidate for DPPH reduction. The overall results show that the efficacy of SiO2-Zn@Fe2O3 nanofibers for inhibition was more pronounced than that of individual iron oxides.

Green synthesis, characterization, antimicrobial and antioxidant activities of zinc oxide nanoparticles using Helichrysum arenarium extract

Active substance production at the nano-level attracts attention in the scientific world due to its wide application area. Different methods are used for the biosynthesis of nanoparticles. Recent studies have focused on non-toxic, environmentally friendly synthesis methods. Nanoparticles obtained by green synthesis using various biological elements such as plants, microorganisms and proteins have taken part in many scientific studies. Plants, which have an important potential in active ingredient production, are highly preferred in nanoparticle production. Scanning Electron Microscope and Energy Dispersive X-Ray Analysis (SEM / SEM-EDX), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Ultraviolet visible light absorption Spectroscopy (UV-vis) techniques were used for the structural and morphological characterization of Zn nanoparticles obtained by green synthesis using Helichrysum arenarium plant extract and ZnO.The antioxidant capacity of Zn NPs/Ha structures was determined by performing the DPPH test. Antimicrobial effects of zinc nanoparticles on six different pathogens (Bacillus cereus ATCC 10876, Escherichia coli ATCC 25952, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATTC 29213, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATTC 90028) were investigated. As a result of this studies, it has been observed that it has an inhibitory effect against some pathogen microorganisms. It has also been found that its antioxidant content is at a significant level.

Duality of foam stabilization

Can a foam reversibly switch between particle and surfactant stabilization? Sure it can. Foams are usually stabilized either by surfactant or hydrophobic nanoparticles. Their combination often worsens the stability of the foam, with surfactant adsorption on the particles causing complex behavior. A system that shifts between both types of mechanisms is desirable both for fundamental studies and practical applications. We developed a system consisting of aqueous solution of 0.1 mM sodium dodecyl sulfate (SDS) + 1.23 mM ZnSO4 + 1.23 mM ethylenediaminetetraacetic acid (EDTA). The foam was produced by the shaking method. The pH value was varied by small additions of HCl or NaOH. We tuned the foam lifetime from 15 to 20 s (at pH = 3 – 6), to ~ 180 s near pH = 1, and increase it in the pH range of 6–12, reaching 15 min at pH = 12. This is due to emerging of nanoparticles of Zn(OH)2 at pH > 8, smoothly switching between the stabilization mechanisms. The nano-suspension of Zn(OH)2 is transparent due to the low aggregation. The low cost (<$1 per metric ton) and the large timescales makes our system desirable for industrial applications.

Impact of Zn Nanoparticles Synthesized via Green and Chemical Approach on Okra (Abelmoschus esculentus L.) Growth under Salt Stress

The study investigated the green and chemical approaches for the preparation of Zn nanoparticles and their effect on the growth of okra plants under saline conditions. The leaf extract of Sorghum bicolor L. was used for the green synthesis of zinc nanoparticles (Zn-GNPs). Zinc nanoparticles (Zn-NPs) were also produced by the co-precipitation method (Zn-CNPs). The synthesized NPs were characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) and were applied foliarly in the range of 0.1%, 0.2%, 0.3% on okra plants. A marked increase in the shoot and root fresh and dry weight (g) and chlorophyll contents were observed under normal and saline conditions. An increase in antioxidant activity was observed under saline conditions. However, the foliar application of 0.3% Zn-GNPs was helpful in the regulation of the antioxidant defense system under a saline environment. Based on the results, it can be concluded that the use of Zn-GNPs is the most promising eco-friendly approach in mitigating salinity stress.