Synthesis Of ZnO Nanoparticles Research Articles

Synthesis and Characterization of ZnO Nanoparticles and Their Application on Cotton Fabrics to Obtain Superhydrophobic Surfaces

حضرت جسيمات أوكسيد الزنك النانوية ZnO (NPs) بطريقة كيميائية رطبة عند درجتي حرارة مختلفتين (30-90) ̊C باستخدام كلوريد الزنك كبادئ في وسط مائي. تم توصيف جسيمات أوكسيد الزنك النانوي المحضر باستخدام المجهر الإلكتروني الماسح (SEM) ,حيود الأشعة السينية (XRD) ، وطيف الأشعة تحت الحمراء (FTIR) ، أشارت أنماط الأشعة السينية الى بنية سداسية (wurtizte) بمتوسط حجم بلوري (19.5-23nm) لجسيمات أوكسيد الزنك المحضرة عند درجتي الحرارة (30-90 ̊C)على التوالي. أظهرت صور المجهر الالكتروني الماسح أنه مع زيادة درجة الحرارة ، تغير شكل جسيمات أوكسيد الزنك النانوي من الأسلاك النانوية إلى االشكل الكروي . لتصنيع قماش قطني فائق المقاومة للماء. تم غمر القماش في محلول غروواني لأوكسيد الزنك بتركيز (1٪) ,ثم تعديله لاحقًا بحمض الشمع . تم توصيف القماش القطني المعالج باستخدام المجهر الإلكتروني الماسح (SEM) واختبار زاوية التماس (CA) .أظهرت نتائج المجهر الالكتروني الماسح أن جسيمات أوكسيد الزنك النانوي المحضر عند(90 ̊C) خلق خشونة على سطح القطن أفضل من جسيمات أكسيد الزنك النانوي المحضرعند (30 ̊C). أظهرت نتائج اختبار زاوية التماس CA خصائص فائقة الكره للماء لعينات أوكسيد الزنك النانوي المحضر عند(90 ̊C) ، بينما أظهرت عينات أوكسيد الزنك النانوي المحضر عند(30 ̊C) خصائص كارهة للماء فقط بعد التعديل بحمض الشمع. تم استخدام تراكيز مختلفة من حمض الشمع لجعل سطح أوكسيد الزنك كارهاً للماء. أظهرت نتائج زاوية التماس (CA) أن القماش القطني المعالج بأوكسيد الزنك النانوي المحضر عند الدرجة (90 ̊C) المعدل ب 1٪ وزناً من حمض الشمع أظهر سطحاً فائق الكره للماء بزاوية تماس (CA=154̊ ).

Facile synthesis of ZnO nanoparticles using Nigella Sativa extract and its role as catalyst in production of bio-oil and degradation of methylene blue dye

Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized using an environmentally benign biogenic approach employing an extract of kernels of Nigella Sativa (kalonji). The presence of primary and secondary metabolites in Nigella Sativa extract acted as the capping and reducing agent. The as-synthesized ZnO NPs were characterized using various advanced techniques i.e., UV, SEM, XRD, EDS, TGA, DSC, and FTIR spectra. UV characterization of ZnO NPs revealed a peak within the 350-400 cm−1 range, confirming their successful formation. XRD spectra revealed that the particles possess a nano-rods and platelets structure, with an average size of 65 nm. XRD analysis revealed that the particles possess a size of 65 nm with a nano-rods and platelets structure. FTIR spectra of the ZnO NPs exhibited a peak at a wavenumber range of 500–600 cm−1. The newly fabricated ZnO NPs were utilized in a pyrolysis reaction for the production of high-yield bio-oil, resulting in a maximum yield of 65.6 % at 350 °C. The spectra of the bio-oil display distinct peaks at 1340 cm−1, 2923.6 cm−1, and 1617 cm−1, which suggest the existence of phenolic and carbonyl chemicals. After incubating for 24 h under UV light, they also demonstrated significant catalytic degradation of methylene blue dye. The highest degradation was recorded to be an average of 71 % in 60 min of UV exposure. Taken together, ZnO NPs developed by eco-benign methods have the potential to be implemented as a novel catalytic system in the production of bio-oil as well as the remediation of dye-harboring industrial wastewater.

Facile biosynthesis of zinc oxide nanoparticles (ZnO NPs) using Lupinus albus L (Gibto) seed extract for antibacterial and photocatalytic applications

This study aimed to synthesize zinc oxide nanoparticles (ZnO NPs) from Lupinus albus L. (white lupin) seed extract and investigate their photocatalytic and antibacterial applications. Phytochemical analysis of the seed extract revealed the presence of flavonoids, polysaccharides, alkaloids, and phenolic compounds. Three ZnO NP samples were prepared using different ratios of the seed extract and zinc nitrate and one sample without seed extract as a control. The nanoparticles were characterized using various techniques, and the average crystallite sizes were found to be in the range of 20.96–30.67 nm, exhibiting a hexagonal wurtzite structure. The photo catalytic activity of the ZnO NPs was evaluated by the degradation of malachite green dye under visible light. The results showed that ZnO NPs synthesized with the seed extract, particularly the 9:1 and 3:2 ratios, exhibited higher photocatalytic activity, with degradation efficiencies of 98 % and 97 %, respectively, compared to the ZnO NPs prepared without the extract (89 % degradation). The antibacterial activity of the ZnO NPs was assessed against four bacterial strains using the disc diffusion method. The ZnO NPs synthesized with the seed extract demonstrated the greatest activity against Klebsiella pneumonia, with an inhibition zone of 15 ± 0.58 mm, while the ZnO NPs without the extract showed lower antibacterial activity. In conclusion, the green synthesis of ZnO NPs using Lupinus albus L. seed extract is a promising approach for the development of materials with efficient photocatalytic and antibacterial properties.

Antibacterial evaluation of polyvinyl alcohol/polyvinyl pyrrolidone/chitosan nanocomposite embedded curcumin@zinc oxide

This study focuses on the fabrication and characterization of PVA/PVP/Cs (Polyvinyl alcohol/Polyvinyl Pyrrolidone/Chitosan) composite membranes embedded with ZnO (zinc oxide) nanoparticles and curcumin as a natural polyphenol with well-known antimicrobial properties. A series of nanocomposite membranes were successfully developed via a solution casting method with varying ZnO loading (2–20 wt%) and fixed 5 wt% curcumin content and physiochemically characterized. Structural and compositional analyses using XRD, FESEM, EDX, and TEM characterizations confirmed the successful incorporation and homogeneous distribution of crystalline ZnO nanoparticles within the amorphous PVA/PVP/Cs polymer matrix. The estimated size of the synthesized ZnO nanoparticles was measured to be around 18–22 nm. TGA thermograms revealed the nanoparticles catalyzed minor reductions in thermal stability while enhancing the residual char at elevated temperatures, a function of their increasing loading fractions. These compositionally tuned PVA/PVP/Cs-ZnO-curcumin nanocomposites exhibited potent antimicrobial efficacy against selected Gram-positive and Gram-negative bacterial strains. The PVA/PVP/Cs-ZnO-curcumin nanocomposites demonstrated tunable antimicrobial activity against bacterial strains, which pave the foundation of eco-friendly, sustainable materials for addressing antimicrobial challenges in biomedical and environmental disinfection applications.

Biogenic Green Synthesis of Zinc Oxide Nanoparticles from Defatted Coconut Presscake for Wastewater Treatment

Defatted coconut meat presscake is a by-product of coconut milk production, often discarded or used as low-value products, but has the potential to treat wastewater. This study aimed to characterize zinc oxide nanoparticles (ZnO NPs) synthesized from defatted coconut meat presscake and determine their effect on the degradation of contaminants in wastewater and antibacterial properties. The nanoparticles were synthesized via a co-precipitation method using zinc nitrate as a precursor and defatted coconut meat presscake extract as a reducing agent. The nanoparticles were characterized using FTIR (Fourier Transform Infrared Spectroscopy), FE-SEM (Field-Emission Scanning Electron Microscopy), XRD (X-ray diffraction), and TGA (Thermogravimetric Analysis). The ZnO NPs exhibited a hexagonal wurtzite structure with an average size of 54 nm. The photocatalytic degradation of methylene blue under UV light irradiation showed a degradation efficiency of 79.5% within 180 minutes. Treated wastewater with ZnO NPs at concentrations of 0.5, 1, and 5 mg/L showed a significantly reduced microbial load, with averages of 10.2×106, 8.3×106, and 3.8×106 CFU/mL, respectively, compared to untreated wastewater (16.5×106 CFU/mL), indicating the antimicrobial properties of ZnO NPs. Therefore, ZnO NPs synthesized from defatted coconut meat presscake extract offer an eco-friendly solution for efficiently treating wastewater from the food industry.

Synthesis of Zinc Nanoparticles in Hibiscus sabdariffa Plant Extract and Investigation of Its Antimicrobial Properties

Background: The use of nanotechnology in various biomedical and pharmaceutical fields is expanding rapidly. Objectives: The aim of this study was to synthesize zinc nanoparticles using Hibiscus sabdariffa plant extract and investigate their antimicrobial properties. Methods: In this experimental study, the aqueous extract of sour tea was mixed with a 0.1 M zinc sulfate solution at a 1:1 ratio and allowed to react for 15 minutes at room temperature to produce nanoparticles. The synthesis of zinc oxide nanoparticles was confirmed using spectrophotometric methods, measuring the average diameter of nanoparticles, X-ray diffraction, and scanning electron microscopy (SEM). The minimum inhibitory concentration (MIC) of the zinc oxide nanoparticles was then measured against standard strains. Results: The results showed that the largest inhibition zone diameter was observed at a concentration of 1024 μg/mL against Listeria monocytogenes, while the smallest inhibition zone was observed against Aeromonas hydrophila. At a concentration of 512 μg/mL, an inhibition zone of 10 mm was developed against two strains: Vibrio cholerae and Escherichia coli. Conclusions: Based on the results of this study, zinc oxide nanoparticles, along with the sour tea aqueous extract and zinc sulfate, exhibited antibacterial properties. However, the most pronounced antimicrobial effects were observed with the zinc oxide nanoparticles.

Plant-mediated green route to the synthesis of zinc oxide nanoparticles: in vitro antibacterial potential

AbstractThe plant-mediated, sustainable, facile, eco-friendly, and simple green approaches for the fabrication of metal oxide nanoparticles (NPs) have recently attracted the ever-increasing attention of the scientific community. To date, there has not been any research on green synthesis of ZnO-NPs by Piper guineense (Uziza) seeds widely used as a therapeutic agent is the novelty of the current study. The bioaugmented ZnO-NPs have been manufactured by Uziza seed extract using zinc acetate dihydrate as the precursor and sodium hydroxide with calcination. The hexagonal/spherical crystalline structure at high purely with a mean size of 7.39 nm was confirmed via XRD and SEM analyses of ZnO-NPs. A strong absorption peak at about 350 nm, specific for ZnO-NPs, was observed by a UV-visible spectrometer. The optical bandgap of ZnO-NPs was estimated as about 3.58 eV by the Kubelka-Munk formula. FTIR findings indicated the presence of biofunctional groups responsible for the bioreduction of bulk zinc acetate to ZnO-NPs. The growth rates of E. coli (ATCC 25,922) significantly decreased with ZnO-NPs exhibited compared to the controls. This is making ZnO-NPs promising effective candidates for medical sectors and environmental applications. This current study is hoped to supply a better understanding of the phytosynthesis of ZnO-NPs and promote the advance of green approaches based on plants.

Zinc oxide nanoparticles derived from Penicillium griseofulvum mitigate DMBA/TPA-promoted mice skin carcinogenesis by modulating NF-ĸB associated signalling.

This study investigates the synthesis of zinc oxide nanoparticles using Penicillium griseofulvum (ZnONPs-PG) and their potential role in preventing DMBA/TPA-induced skin cancer. The synthesis process involved using a 1-mM zinc acetate dihydrate as a precursor in P. griseofulvum. Various analytical techniques, including FTIR spectroscopy, UV-Vis, TEM, XRD, and DLS, were utilized to characterize the ZnONPs. The efficacy of ZnONPs-PG was then evaluated in a DMBA/TPA-induced skin cancer model. Mice were treated topically with DMBA/TPA in acetone (200μL) over 2weeks, with treatments continuing for 20weeks. Results showed 100% tumor occurrence, histological changes, elevated lipid peroxidation (LPO) levels, and decreased antioxidant levels in DMBA/TPA-treated mice. However, topical application of ZnONPs magnificently reverted the tumor occurrence, histological changes, elevated malanoldehyde and hydrogen peroxide levels; decreased antioxidant levels in DMBA/TPA-treated mice. ZnONPs-PG treatment suppressed the increased levels of inflammatory markers (COX-2, iNOS and NF-κB,) and cell proliferation markers (Cyclin-E1, Cyclin D1, VEGF, TGF-β1) exposed mice. In addition, ZnONPs-PG treatment decreased the DMBA/TPA-induced anti-apoptotic Bcl-2 protein and increasing the expression of pro-apoptotic markers (Bax and caspase 3) in skin tissues. Thus, ZnONPs-PG may prevent skin carcinogenesis through its potent antioxidant properties and inhibiting NF-κB-mediated inflammatory and proliferation pathways.

Evaluating the electrochemical boost and antimicrobial power of biogenic zinc oxide-polyaniline nanocomposite

Bio-based materials from bark, wood, leaves, and fruits have several uses in nanotechnology. Anthocephalus Cadamba is a biological reducing agent in nanocomposites. The fruit of Anthocephalus Cadamba is used to synthesize ZnO nanoparticles and polyaniline to make a ZnO-PANI nanocomposite. We describe UV–visible, FTIR, XRD, and SEM data to support synthesis. The dielectric constant is highest in the ZnO-PANI nanocomposite compared to pure ZnO nanoparticles. The Nyquist plot semicircular arc confirms temperature-induced conductivity improvement in nanocomposites. Nanocomposites have 1.3 ×10−2 S/m higher conductivity than nanoparticles. The ZnO-PANI nanocomposite has the greatest specific capacitance (Csp) of 1.3 × 10−2. This work suggests that ZnO-PANI nanocomposite electrodes might be useful supercapacitors in energy storage devices with antibacterial properties. XTT assay and biofilm formation assay using CLSM (Confocal laser scanning microscope) indicated that Integration of ZnO-PANI nanocomposites onto biofilm-prone surfaces like medical devices or implants inhibited bacteria adhesion and biofilm growth in antimicrobial investigations.

Electrochemical incorporation of PVA-ZnO composite on Screen printed carbon electrode as dopamine sensor

In this study, a composite of zinc oxide (ZnO) nanoparticles and polyvinyl alcohol (PVA) on a screen-printed carbon electrode (SPCE), termed SPCE/PVA/ZnO electrode, was utilized to develop an enhanced electrochemical sensor for dopamine (DA) detection. A novel method for synthesizing ZnO nanoparticles using almond gum at room temperature was introduced. X-Ray Diffraction (XRD) analysis confirmed the crystallinity of the ZnO nanoparticles. The SPCE/PVA/ZnO electrode was fabricated and characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Cyclic voltammetry was employed to measure DA, revealing a linear increase in the electrochemical oxidation signal of DA at the SPCE/PVA/ZnO composite from 100 to 600 μM. The sensor demonstrated a limit of detection of 0.1208 mM and a sensitivity of 0.01822 μAμM−1cm−2. The SPCE/PVA/ZnO sensor showed acceptable performance in evaluating dopamine in real sample study.

Photocatalytic Degradation of Toxic Rhodamine B Dye by Green‐Synthesised Activated Carbon‐Supported Cobalt Doped ZnO With Further Assessment of ZnO Nanoparticles in Antimicrobial Applications

AbstractThis work investigates the synthesis of ZnO nanoparticles, cobalt (Co)‐doped ZnO, and Activated Carbon (AC) ‐Co doped ZnO via green precipitation technique. AC developed from lotus stems and precipitated by lotus leaf extract. Comprehensive structural, optical, and morphological investigations by FT‐IR, XRD, FE‐SEM, EDX, HR‐TEM, UV‐DRS, PL, and XPS studies are used to characterize the photocatalysts. The ZnO nanoparticles are shown to have a hexagonal phase by XRD examination. The results of the FT‐IR analysis proved that specific chemical bonds exist in the ZnO, Co−ZnO, and AC−Co‐doped ZnO nanocomposites. FE‐SEM images revealed spherical morphology with aggregated, randomly distributed particles with an average size range of ZnO, Co−ZnO and AC−Co−ZnO are 59.55, 42.55, 41.16 nm. The band gap energies of ZnO, Co ‐ZnO, and AC−Co‐ ZnO, are found to be 3.10, 2.57, and 1.94 eV, respectively. Rhodamine B is used as a model contaminant to assess the samples under UV‐light driven photocatalytic effectiveness. The photocatalytic degradation efficiency (%) of the pristine ZnO, Co‐doped ZnO, and AC−Co‐doped ZnO catalysts are increased to 61.76, 74.86, and 91.46 % after 140 minutes of under UV‐light irradiation. Degradation rate constant (k) of the AC−Co−ZnO photocatalyst is found to be greater than that of pristine ZnO and Co−ZnO. Due to the synergistic effect of the AC and Co metal dopants and the spherical morphology of the AC−Co−ZnO sample, which boosted UV‐visible light absorption with reduced charge carrier recombination, resulting in outstanding photocatalytic activity. The study also investigated the bioactive effect of the samples on six bacterial species, revealing that the AC−Co‐doped ZnO nanocomposite has the most enhanced inhibitory effects against gram‐positive and gram‐negative bacteria. Consequently, medical wound dressing materials which helps to promote early healing by preventing microbial contamination.

Photocatalytic and eco-emission applications of green synthesized ZnO-CB nanoparticles

Herein, we report the synthesis of ZnO nanoparticles (ZnO-CB NPs) by employing the solution combustion method using an aqueous extract of brinjal calyxes as fuel. Characterization techniques, such as X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR), UV–visible spectroscopy, and Scanning electron microscopy (SEM), were used to investigate the structural, optical, and morphological properties of synthesized nanoparticles, respectively. Highly porous hexagonal crystalline ZnO-CB NPs with less than 7 nm particle size were obtained. The photocatalytic performance of synthesized material is measured with Malachite green (MG), Basic brown 1 (BB1), and Acid orange 36 (AO36) as benchmark dyes. It showed that the synthesized material worked effectively under pH 10 with UV light irradiation. The synthesized ZnO-CB NP shows good removal effectiveness of the MG, BB1, and AO36 dyes with 99.3 %, 99.6 %, and 99.5 %, respectively, which can be promising photocatalysts for ecological applications such as wastewater remediation. Further, the synthesized ZnO-CB NP was used as blends in the methyl ester of Millettia pinnata oil (MPME), which is blended 20 % with commercial diesel (MPME20). The synthesized ZnO-CB NP was added to the MPME20 in varying amounts to ascertain its effects on the quality of emissions of various greenhouse gases such as hydrocarbons, COx, and NOx. Moreover, brake thermal efficiency (BTHE) and brake-specific fuel consumption (BSFC) were studied for the blends. The blend MPME20 with 25 mg of ZnO-CB NP, i.e., MPME20-25 mg, ZnO-CB, displays the best performance and reduced emissions.

Effective removal of toxic mixed azo dyes and Cr (VI) ions from wastewater using an integrated approach

The textile industry generates a significant amount of wastewater, including hazardous dyes, pigments, and heavy metals. The integrated approach of isolated bacterial strain and the bacterially synthesized ZnO nanoparticles was used in the removal of mixed azo dyes and Cr(VI) in a lab-scale bioreactor. It resulted in 77.19 % bromocresol purple (4th day), 50.11 % on bromocresol blue (3rd day), and 50.59 % bromocresol green (4th day) removal. Mixed azo dyes and Cr(VI) were removed using bacterial strain, which showed the maximum removal of Cr(VI) was 73.6 % at 25 ppm (3rd day) and mixed azo dyes removal was a maximum of 49.01 % at 75 ppm. A lab-scale reactor study using bacterial strain resulted in 45.89 % (5th day) of mixed azo dye and Cr(VI) removal. However, when the reactor was employed with synthetic wastewater and bacterially synthesized ZnO nanoparticles, achieved a maximum removal of 53.84 % at 120 min. Also, a phytotoxicity study on the Cicer arietinum plant with different concentrations of mixed azo dyes and chromium concentrations showed a maximum length of 5.5 cm at 100 ppm (3rd day). The bacterial strain and synthesized ZnO nanoparticles integrated technique providing an economically viable and scale-up solution for wastewater treatment techniques.

Exogenously applied nano-zinc oxide mitigates cadmium stress in Zea mays L. through modulation of physiochemical activities and nutrients homeostasis

The increasing levels of cadmium (Cd) pollution in agricultural soil reduces plant growth and yield. This study aims to determine the impact of green synthesized zinc oxide nanoparticles (ZnO-NPs) on the physiochemical activities, nutrition, growth, and yield of Zea mays L. under Cd stress conditions. For this purpose, ZnO-NPs (450 ppm and 600 ppm) synthesized from Syzygium aromaticum were applied through foliar spray to Z. mays and also used as seed priming agents. A significant decline in plant height (35.24%), biomass production (43.86%), mineral content, gas exchange attributes, and yield (37.62%) was observed in Cd-spiked plants compared to the control. While, 450 ppm ZnO-NPs primed seed increased plant height (18.46%), total chlorophyll (80.07%), improved ascorbic acid (25.10%), DPPH activity (26.66%), and soil mineral uptake (Mg+2 (38.86%), K+ (27.83%), and Zn+2 (43.68%) as compared to plants only spiked with Cd. On the contrary, the foliar-applied 450 ppm ZnO-NPs increased plant height (8.22%), total chlorophyll content (73.59%), ascorbic acid (21.39%), and DPPH activity (17.61%) and yield parameters; cob diameter (19.45%), and kernels numbers 6.35% enhanced compared to plants that were spiked only with Cd. The findings of the current study pave the way for safer and more cost-effective crop production in Cd-stressed soils by using green synthesized NPs and provide deep insights into the underlying mechanisms of NPs treatment at the molecular level to provide compelling evidence for the use of NPs in improving plant growth and yield.

Influence of annealing temperature on the structure, morphology, optical property and antibacterial response of phytochemicals-assisted synthesized zinc oxide nanoparticles

Abstract Antibiotic overuse has caused a variety of bacterial pathogens to develop new resistance mechanisms. As a result, discovering an appropriate replacement for the standard antibiotics has become an immediate concern. The present work demonstrates a facile, eco-friendly and economical method for the synthesis of hexagonal wurtzite zinc oxide nanoparticles (ω-ZONPs) using the ethanolic extract of triphala. Gas chromatography–mass spectrometry analysis of the triphala extract proved the presence of certain secondary metabolites, which aids in the formation of ω-ZONPs. The influence of annealing temperature on the antibacterial action of as-synthesized ω-ZONPs was studied for three different annealing temperatures. X-ray diffraction, dynamic light scattering, field emission electron microscopy and energy dispersive X-ray spectroscopy analyses were used to examine the impact of annealing temperature on the structure, particle size and morphology of ω-ZONPs. Fourier transform infrared spectra revealed the change in intensity of the characteristic peaks in ω-ZONPs with different annealing temperatures. From UV–Visible diffuse reflectance spectroscopy, variation in the band gap of ω-ZONPs with increasing annealing temperature was detected. Kirby Bauer disc diffusion was adopted to examine the antibacterial potential of ω-ZONPs against bacterial strains such as Staphylococcus aureus, Enterococcus faecium, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The ω-ZONPs annealed at 200 °C inhibited the growth of three bacterial pathogens, E. coli, B. subtilis and P. aeruginosa and exhibited effective antibacterial activity in comparison with ω-ZONPs annealed at relatively high temperatures. Thus, the antibacterial potential of ω-ZONPs could be further explored as disease controlling agents and such prototypes could be made available for commercial mass production.

Bioinspired Synthesis and Characterization of Dual-Function Zinc Oxide Nanoparticles from Saccharopolyspora hirsuta: Exploring Antimicrobial and Anticancer Activities.

Microbial synthesis offers a sustainable and eco-friendly approach for nanoparticle production. This study explores the biogenic synthesis of zinc oxide nanoparticles (ZnO-NPs) utilizing the actinomycete Saccharopolyspora hirsuta (Ess_amA6) isolated from Tapinoma simrothi. The biosynthesized ZnO-NPs were characterized using various techniques to confirm their formation and properties. UV-visible spectroscopy revealed a characteristic peak at 372 nm, indicative of ZnO-NPs. X-ray diffraction (XRD) analysis confirmed the crystalline structure of the ZnO-NPs as hexagonal wurtzite with a crystallite size of approximately 37.5 ± 13.60 nm. Transmission electron microscopy (TEM) analysis showed the presence of both spherical and roughly hexagonal ZnO nanoparticles in an agglomerated state with a diameter of approximately 44 nm. The biogenic ZnO-NPs exhibited promising biomedical potential. They demonstrated selective cytotoxic activity against human cancer cell lines, demonstrating higher efficacy against Hep-2 cells (IC50 = 73.01 µg/mL) compared to MCF-7 cells (IC50 = 112.74 µg/mL). Furthermore, the biosynthesized ZnO-NPs displayed broad-spectrum antimicrobial activity against both Pseudomonas aeruginosa and Staphylococcus aureus with clear zones of inhibition of 12.67 mm and 14.33 mm, respectively. The MIC and MBC values against P. aeruginosa and S. aureus ranged between 12.5 and 50 µg/mL. These findings suggest the potential of S. hirsuta-mediated ZnO-NPs as promising biocompatible nanomaterials with dual applications as antimicrobial and anticancer agents.

Gompherna globosa flower extract-driven ZnO nanoparticles for enhanced antimicrobial and photocatalytic properties

The aqueous extract of Gomphrena globosa flowers was utilized for the first time as an effective capping and reducing agent for the synthesis of zinc oxide nanoparticles (ZnO NPs). The synthesized nanoparticles were examined using x-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive x-ray analysis (EDAX), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) and UV–vis spectroscopy. XRD revealed the single-phase wurtzite structure of ZnO nanoparticles with a P63mc space group with an average size of 23 nm. The band gap of synthesized ZnO nanoparticles was determined as 3.16 eV from UV–vis spectroscopy. The rod-shaped structure of the synthesized ZnO NPs was revealed by SEM. The presence of the elements Zn & O was confirmed by EDAX. TEM and SAED confirmed that the average particle size was 26 nm and that the material was polycrystalline. The bio-inspired ZnO NPs achieved outstanding degradation activity of 95.4% against Malachite Green dye after 20 min of UV illumination. The antibacterial properties of the green synthesized nanoparticles were assessed in relation to gram-positive (Staphylococcus sp., Bacillus sp.,) and gram-negative (E. coli, Klebsiella sp.) bacteria. ZnO nanoparticles possess strong antifungal property against a pathogenic fungus Aspergillus niger. This study shows that green-synthesized ZnO nanoparticles derived from Gomphrena globosa flower extract are recommended for use in anti-microbial and photocatalytic applications.

Photocatalytic, antibacterial and optoelectronic applications of Terbium doped Zinc oxide nanoparticles prepared via chemical co-precipitation method

This work demonstrates facile synthesis of Tb-doped ZnO nanoparticles and investigates their structural, optical, electrochemical, photocatalytic, and antibacterial performance. XRD patterns of undoped and doped ZnO nanoparticles confirm a hexagonal wurtzite structure. TEM and SAED reveals that the particle size is 14–38 nm. SEM images show that ZnO and Tb-doped ZnO nanoparticles have smooth surfaces, and elemental composition was confirmed by EDX analysis. UV–Visible spectrophotometry studies, reveals that the band gap narrows with increasing Tb concentration. Photoluminescence spectra at room temperature showed a band at 538 nm, indicating zinc vacancies and green emission. Tb-doped ZnO with x = 0.075 exhibited the highest photocatalytic activity for degrading Rose Bengal dye compared to other photocatalysts. The electrochemical behaviour of Catechol (CC), Hydroquinone (HQ), and Bisphenol-A (BPA) at Tb–ZnO/MCPE was studied. The modified electrode process for CC and BPA was adsorption-controlled, and simultaneous recognition of CC, HQ, and BPA was achieved, showing an increase in current. Electro polymerization of poly (Congo red) on Tb–ZnO/MCPE confirmed clean deposition on the surface, enhancing electrocatalytic activity. The antibacterial efficacy was tested using the traditional disc diffusion method, showing effective inactivation of bacterial strains, including pathogens such as S. aureus (G+) and E. coli (G-).

Spectroscopic investigations of green synthesized zinc oxide nanoparticles (ZnO NPs): antioxidant and antibacterial activity

In the recent decade, zinc oxide nanoparticles (ZnO NPs) have been widely explored owing to their versatile properties and prodigious demands in the drug delivery, medical, energy storage, cosmetics, and the healthcare sectors. Therefore, the current work opts for an environmentally benign method to prepare ZnO NPs. The leaf extract of Calendula officinalis L. acts as a reducing agent for the metal ions; therefore, in the current research, ZnO NPs were prepared via green route by using Calendula officinalis leaf extract. Furthermore, the ZnO NPs were analysed with different spectroscopic techniques to confirm the structure and stability of nanomaterials. The prepared ZnO NPs were characterized by XRD, FE-SEM, FT-IR and UV–Vis studies. Also, the antioxidant and antimicrobial properties of the synthesized ZnO NPs were investigated. The XRD result of synthesized ZnO NPs showed the crystalline size 28.23 nm with wurtzite hexagonal structure along with the most intense peak (101). Following preliminary confirmations of the intended ZnO NPs, both big and small agglomerated forms were observed in the FE-SEM, which is often used to determine their exterior assembly. Further, the results of Fourier transform infrared spectroscopy (FT-IR) indicated the formation of pure ZnO NPs with an absorption peak of the Zn–O bond between 4000 cm−1 and 500 cm−1 and no discernible peak in the monitoring range. The UV–Vis spectrum of the green synthesized ZnO NPs were revealed two prominent absorption peaks at 355 nm and 370 nm with energy band gap of 2.986 eV. Using the 1, 1-di phenyl-2-picrylhydrazyl (DPPH) test, the antioxidant activity of the described ZnO NPs was assessed. It demonstrated how, ZnO NPs significantly increased their antioxidant activity by scavenging 1, 1-di phenyl-2-picrylhydrazyl (DPPH) free radicals. It could be seen that synthesis of the naturally occurring plant product ZnO NPs have been acting as an alternate of chemical antioxidant. The antimicrobial analysis was also performed with the help of disk diffusion method where three multi-drug resistant human pathogens namely Staphylococcus aureus, Klebsiella pneumoniae and E.coli were used. The Zone of Inhibition diameter values are 35.2 mm ± 0.9, 23.6 mm ± 0.1 and 13.5 mm ± 0.1, respectively, which showed that the ZnO NPs was highly effective against S. aureus. Thus, the green synthesis method of ZnO NPs using leaf extract of Calendula officinalis is evidence that it is superior and environmentally friendly method for the preparation of ZnO NPs and hence it can be utilized in various nano-medicine approaches.

Design synthesis of ZnO nanoparticles on Co3O4 nanosheet with rich oxygen vacancies for rapid detection of NO2 at room temperature

The solvothermal and wet chemical method was developed to synthesized the p-n heterostructures of the thin porous Co3O4 nanosheets with ZnO nanoparticles. The resulting products were analyzed by using various characterization techniques. The results possessed that the presence of a large number of oxygen defects on the surface of Co3O4-ZnO-7 favors enhancing the NO2 adsorption. Correspondingly, the formation of p-n heterojunction and the large surface area of the material itself increased the carrier density and exposed more active sites, which collectively boost the sensing performance to NO2. The sensor showed a high response of 45.7 (S = Ra/Rg) to 100 ppm NO2 at room temperature (RT = 25 °C), with a short response/recovery time (1.3/25 s), and the lower detection limit of the sensor reached 30 ppb, with good selectivity, reproducibility and stability. This study will offer the opportunity to develop new sensors with high response and fast response-recovery to NO2 at room temperature.