Synthesis Of Nickel Oxide Nanoparticles Research Articles

Investigations on the microbial activity and anti-corrosive efficiency of nickel oxide nanoparticles synthesised through green route

Abstract Researchers have shown considerable interest in the environmentally friendly synthesis of several nanoparticles particularly metal nano particles due to their multifaceted applications. The target of the current research includes the synthesis of nickel oxide nanoparticles (NiO-NPs) through the green route using the bark extract from Acacia Nilotica, and analyzed their chemical and surface morphological features using XRD, SEM, EDX, IR, UV–vis and photoluminescence spectroscopy. In addition, the corrosion inhibition ability and antimicrobial activity of the extract were also studied. The XRD analysis indicated that the NiO exist in the form of nanoparticles. It showed the formation of pure cubic NiO-NP with a prominent peak at 43.28° reflected from the plane (200). The crystallite size was found to be 15.83 nm. The SEM micrographs revealed that NiO-NPs appeared to be a bulk cluster-like structure on their surface.The EDX analysis displayed the presence of Ni and oxygen atoms. The photoluminescence spectrum demonstrated that the green synthesized metal oxide nanoparticles have a modified emission band due to the presence of oxygen deficiencies and induced surface imperfections. The Fourier transform infrared spectroscopy (FTIR) confirmed the association of peaks with the C–H and Ni–O bonds. The UV–vis study showed a maximum absorption at 264 nm. A study on the inhibition efficiency towards microbes confirmed that the prepared NiO-NPs have a good inhibition against selected microbes such as S. aureus, E. coli, Candida albicans, A. Niger. The mass loss system showed restraint 93.68 % effectiveness in the mild steel, and the electrochemical study supported the formation of a defensive protective layer on the cathodic locales of the carbon steel surface inhibiting corrosion.

Microwave assisted synthesis of nickel oxide nanoparticles at different pH via sol gel method: Experimental and first-principles investigations

Nickel oxide (NiO) nanoparticles were synthesized at different pH levels via a sol–gel method and calcined using microwave assistance. The study explored the effects of pH on NiO nanoparticles morphology, structure and electronic properties. Density functional theory (DFT + U) calculations were employed to investigate the structural and electronic properties of the material. NiO synthesized at pH 8 displayed superior crystallinity and particle size distribution, with spherical-like nanoparticles averaging 3 nm in size. DFT + U calculations revealed a band gap of 4.07 eV and a surface energy convergence of 51 meV/Å2, indicating stability. These findings suggest pH 8 as the optimal condition for NiO synthesis. Electrochemical tests demonstrated a high specific capacitance of 87.7F g−1 at a scan rate of 10 mV s−1, indicating promising electrochemical properties for supercapacitor applications.

Phytosynthesis of Nickel Oxide Nanoparticles and Their Antioxidant and Antibacterial Efficacy Studies.

Multidrug-resistant (MDR) bacteria are widely acknowledged as a significant and pressing public health concern. Tribulus terrestris has been used as a health tonic in traditional medicine since ancient Vedic times. It was also utilized to synthesize small, well-dispersed metal nanoparticles (NPs). Thebiosynthesized nickel oxidenanoparticles (NiO-NPs) have a broad spectrum of biomedical uses. The objective of the research was to utilize a green synthesis method to synthesizeNiO-NPsusing Tribulus terrestris, subsequently characterize, and this study aimed to assess the antioxidant and antibacterial effectiveness of these NPs against wound isolates that are resistant to multiple drugs. The synthesis of NiO-NPs was achieved through the titration method, which is a green synthesis approach, and it was characterized by using techniques such as ultraviolet-visible spectroscopy (UV), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM),X-ray diffraction (XRD) analysis, andenergy dispersive X-ray (EDX). The antioxidant activity of theNPs was evaluated using the 2,2-diphenyl-1-picrylhydrazyl(DPPH) assay, and antibacterial activity was done using the agar well diffusion method. IBM SPSS Statistics for Windows, Version 21 (Released 2012; IBM Corp., Armonk, New York, United States)is used for statistical analysis. The biosynthesized NiO-NPs exhibited acolor change from dark brown to dark green, indicating the successful reduction of the NPs.UV analysis peaks were observed at 310-350 nm, whileFT-IRanalysis showed the peaks at various wavelengths such as 629.31cm-1(halo compound; C-Br stretching), 957.80cm-1(aromatic phosphates; P-O-C stretch), 1004.65cm-1 (aliphatic phosphates; P-O-C stretch), 1094.93cm-1(organic siloxane or silicone; Si-O-Si), 1328.38cm-1(dialkyl/aryl sulfones), 1604.88cm-1(open-chainazo-N=N-), 2928.68cm-1 (methylene C-H asym/sym stretch), 3268.65cm-1(normal polymeric "OH" stretch). The crystallinity of the NPs was determined to be 24.7%, while the remaining 75.6% exhibited an amorphous structure. The SEM image revealed a spherically agglomeratedstructure of the nano-ranged size NiO-NPs.TheEDX analysis indicated the presence of elemental compositions Ni (7.4%), O (39.4%), and C (53.3%)in the biosynthesized NiO-NPs. These NPs demonstrated significant antibacterial activity against Pseudomonas aeruginosa and Klebsiella pneumoniae, moderate antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), and the lowest antibacterial activity against Enterococcus faecalis. Our in vitro results demonstrate that the biosynthesized NiO-NPsexhibit significant antioxidant and antibacterial activity. These NPs can be used as a future antimicrobial medication, particularly against MDR clinical wound isolates ofK. pneumoniae, P. aeruginosa, and MRSA.

Synthesis of Silver Nanoparticles by Solanum trilobatum L. Aqueous Extract and Their Antibacterial Activity

ABSTRACT Solanum trilobatum L. (Solanaceae), commonly known as nightshade, has been traditionally used by various populations to treat a variety of ailments. Environment-friendly alternatives to chemical and physical procedures for the synthesis of nanomaterials have been proposed. In this research, the hot plate combustion method is used to synthesize nickel oxide nanoparticles (AgNPs) from silver nitrate and S. trilobatum leaf extract. According to X-ray diffraction (XRD) tests, the cubic phase was face-centered, had good crystallinity, and had average crystallite sizes. According to morphological studies, the surface has a cylindrical and rod-like morphology, and average particle size estimates from UV-visible spectroscopy (UV), Fourier transform infrared (FT-IR), concur well with XRD, and the bio-reduced silver nanoparticles were characterized. Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Pseudomonas aeruginosa, and the human pathogenic microorganisms were used to investigate the antibacterial efficacy (12.5, 25, 50 μg/mL) of these biologically created silver nanoparticles.

Natural resource-derived NiO nanoparticles via aloe vera for high-performance symmetric supercapacitor

This investigation reported a one-step green synthesis of nickel oxide nanoparticles (NiO NPs) using aloe vera leaves extract solution for their application in a supercapacitor. This method used aloe vera leaves as a reducing agent, which is very simple and cost-effective. The synthesized NPs were thoroughly characterized using various techniques. The X-ray diffraction analysis unequivocally confirmed the crystalline nature; field emission scanning electron microscopy and transmission electron microscopy images showed different shapes and forms of an agglomerated cluster of synthesized NPs. The absorption spectra were recorded from UV visible spectroscopy, while Fourier transform infrared spectroscopy provided insights into the functional groups present. Electrochemical assessments were carried out via cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. These experiments were performed using a 2 M KOH electrolyte within a 1.0 V potential window. Impressively, the single electrode displayed a remarkable specific capacitance of 462 F g−1 at a scan rate of 1 mV s−1 and 336 F g−1 at a current density of 0.76 A g−1. Further, a symmetric two-electrode device (NiO||NiO) has been successfully fabricated by employing a separator between the electrodes. The device exhibited an exceptional specific capacitance of approximately 239 F g−1, along with an energy density of 47.8 Wh kg−1 and a power density of 545 W kg−1 at 1 A g−1 current density within a 1.2 V potential window. The fabricated device also shows a retention capacity of 89% at 10 A g−1 after 2000 cycles with 114% of columbic efficiency. The present study underscores the effectiveness of the green synthesis approach in producing NiO NPs and establishes their potential as highly promising candidates for supercapacitor applications, showcasing both excellent electrochemical performance in a three-electrode system and remarkable stability in a practical two-electrode device. The results collectively highlight the efficacy of the green approach in producing NiO NPs, establishing its potential as a highly promising candidate for supercapacitor application.

Enhanced photocatalytic degradation of polycyclic aromatic hydrocarbons (PAHs) Using NiO nanoparticles

The oncogenic and genetic properties of anthracene, a member of the polycyclic aromatic hydrocarbons (PAHs) family, pose a significant health threat to humans. This study aims to investigate the photocatalytic decomposition of anthracene under various conditions, such as different concentrations of PAHs, varying amounts of NiO (nickel oxide) nanoparticles, and different pH levels under ultraviolet light and sunlight. The synthesized NiO nanoparticles showed surface plasma resonance at 230 and 360 nm, while XRD and SEM analysis confirmed the nanoparticles were cubic crystalline in structure with sizes ranging between 37 and 126 nm. NiO nanoparticles exhibited 79% degradation of pyrene at 2 μg/mL of anthracene within 60 min of treatment. NiO at 10 μg/mL concentration showed significant adsorption of 57%, while the adsorption method worked efficiently (72%) at 5 pH. Photocatalytic degradation was confirmed by isotherm and kinetic studies through monolayer adsorption and pseudo-first-order kinetics. Further, the absorption process was confirmed by performing GC-MS analysis of the NiO nanoparticles. On the other hand, NiO nanoparticles showed antimicrobial activity against Gram negative and Gram-positive bacteria. Therefore, the present work is one of its kind proving the dual application of NiO nanoparticles, which makes them suitable candidates for bioremediation by treating PAHs and killing pathogenic bacteria.

Surface and quantum chemical parameters of nickel oxide nanostructures suited for ultraviolet-assisted cationic dye degradation

Nickel oxide (NiO) nanostructures were synthesized through chemical precipitation and subsequently analyzed using a scanning electron microscopy (SEM) and X-ray diffraction (XRD). Rietveld refinement of XRD data revealed a cubic structure with lattice parameters of a = b = c = 4.173 Å. Fourier transform infrared spectroscopy and energy dispersive X-ray were employed to analyze the functional group and elemental composition of NiO NPs. The ultraviolet diffuse reflectance spectra indicated an optical band gap of 3.08 eV for synthesized NiO nanoparticles. Surface characteristics were evaluated using the Gwyddion open-source application, and parameters including Ra (mean roughness), Rq (mean square roughness), Rsk (surface skewness), and Rku (kurtosis coefficient) were calculated. The chemical properties of NiO were investigated through density functional theory calculations, and the results aligned well with experimental data. Furthermore, a comparative analysis of the photodegradation of methylene blue (MB) and rhodamine B (RhB) in the presence of UV light was examined, and it followed pseudo-first-order rate kinetics with degradation efficiencies of 82.62% (MB) and 71.31% (RhB), respectively. The electric energy per order for the photodegradation process was calculated to be 9.4 × 102 kWh/m3/order (MB) and 11.7 × 102 kWh/m3/order (RhB). Notably, the low electric energy consumption per order indicated a cost advantage for the reactor setup.

Aloe vera extract-assisted sol-gel synthesis of NiOx nanopyramids for supercapacitor application

Green synthesis of metal oxide nanoparticles is a cost-effective and sustainable approach that allows tailoring of the size and shape of the nanostructures for versatile applications. In this study, aloe vera extract-assisted sol-gel synthesis of nickel oxide nanoparticles (NiOx NPs) was explored for supercapacitor application. The NiOx NPs were synthesized at different aloe vera concentrations (2.5 and 5 wt%) and calcination temperatures (300, 400 and 500 °C). The phytochemical-assisted synthesis yielded NiOx nanopyramids with pores on their surface which widens as calcination temperature increases. As confirmed by XRD analysis, NiOx crystallite size also increased at higher calcination temperatures. Upon electrochemical characterization, NiOx-400B which was synthesized with 5 wt% aloe vera extract at 400 °C recorded the highest specific capacitance of 721 F g−1 at 1 A g-1 current density with the energy and power density of 10.38 Whkg−1 and 241.08 W kg-1 respectively. The charge storage mechanisms in the samples were gauged using Dunn's method which revealed that NiOx synthesized at higher calcination temperatures exhibited a greater contribution of the diffusion-controlled process. The optimized composition, NiOx-400B, also demonstrated excellent cycle stability by retaining up to 90.4 % of its original capacitance over 1500 cycles. This work is an attempt to investigate the viability of green synthesized nanoparticles in energy storage applications and the novel NiOx nanopyramid substantiates its prospect as a good electrode material for supercapacitors.

Green synthesis of NiO nanoparticles using a Cd hyperaccumulator (Lactuca sativa L.) and its application as a Pb(II) and Cu(II) adsorbent

The proliferation of heavy metal contamination, namely, lead and copper, has emerged as a pervasive worldwide peril to human existence. One potential solution for addressing this issue is the utilization of nanoparticle adsorption, specifically for nickel oxide nanoparticles. However, to promote environmental sustainability, scholarly studies have identified green synthesis as a prospective methodology. The process of cadmium phytoremediation, although offering a potential remedy for heavy metal contamination, gives rise to apprehensions surrounding the proper disposal of cadmium hyperaccumulator plant biomass. Hence, it is imperative to establish suitable strategies for the disposition or usage of this biomass. The utilization of hyperaccumulator extracts for the eco-friendly production of nickel oxide nanoparticles remains unexplored in the current literature. The main aim of this research is to explore the possible application of Lactuca sativa L. as a plant species with the ability to accumulate high levels of cadmium. The study also seeks to examine the efficacy of utilizing these plants in the fabrication of nickel oxide nanoparticles and evaluate their capacity to absorb lead and copper ions. The characterization of nickel oxide nanoparticles is conducted through a range of techniques, encompassing scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller spectroscopy, and vibrating sample magnetometry. The present work achieved successful utilization of Lactuca sativa L. extract for the manufacture of nickel oxide nanoparticles, which showed notable efficacy as an adsorbent for lead and copper. The synthesis of nickel oxide nanoparticles using an extract from Lactuca sativa L. has demonstrated the viability of utilizing hyperaccumulator biomass in the phytoremediation of cadmium. This finding presents a promising avenue for investigating hyperaccumulator plants as potential sources for nanoparticle synthesis in the field of environment-based nanotechnology development.

High-performance UV photodetector based on nickel oxide loaded with low amount of nitrogen and boron co-doped reduced graphene oxide for bias-switchable photoconductance

In this work, we report a low cost and straightforward chemical synthesis of nickel oxide nanoparticles decorated with low amount of nitrogen and boron co-doped reduced GO for a high-performance UV photodetector. For the first time, NiO/NB-rGO nanomaterial was synthesized following the co-precipitation method and subsequently annealed at 400 °C. The nanomaterial was characterized with several techniques such as SEM, TEM, XRD, and Raman spectroscopy. In addition, the device was subjected to electrical characterizations to determine their responsivity, detectivity, and temporal responses both in the absence of illumination (dark conditions) and under UV illumination of 375 nm. In particular, the studied I-V curve was performed to evaluate the coexistence of positive and negative photoconductivity in our device. The results revealed a better photoresponse of NiO/NB-rGO device to UV light, which showed high responsivity (800 A/W), large detectivity (9.4 ×1011 Jones), and fast rise/fall time (1.38/2.17 s) at reverse bias. Consequently, the Schottky contact of NiO/NB-rGO allowed to switch between carriers’ conduction, which displayed both positive and negative photoconductance at reverse and forward bias.

Plant Extract Mediated Biogenic Synthesis and Characterization of Nickel Oxide Nanoparticles and its Environmental and Antibacterial Applications

This research focuses on the green synthesis of Nickel Oxide nanoparticles (NiO NPs) using Musa paradisiaca, commonly known as banana plant, as a cost-effective and eco-friendly approach. Musa paradisiaca, utilized in traditional medicine, possesses various medicinal properties, including antioxidant, antibiotic, allogeneic, and hypoglycemic antimicrobial attributes. The peduncle extract of Musa paradisiaca serves as a reducing and capping agent for NiO nanoparticle synthesis. Characterization techniques such as XRD, EDX, and UV-vis spectroscopy were employed to analyze the properties of the synthesized NiO nanoparticles. XRD analysis confirmed an average grain size of 15.26nm, while SEM images revealed round cubic-shaped nanoparticles with a highly crystalline structure. The antibacterial activity of NiO nanoparticles was investigated against bacterial strains, including Escherichia coli, Staphylococcus aureus, Bordetella bronchiectasis, and Bacillus subtilis, demonstrating effective antibacterial properties. Furthermore, the catalytic power of the synthesized nanoparticles was evaluated through the degradation of methyl blue and methyl orange dyes under sunlight and UV light. The results indicated superior degradation efficiency under sunlight compared to UV light for both dyes. Additionally, the study explored the adsorption activity of NiO nanoparticles for chromium (VI) at various concentrations, with the best adsorption percentage recorded at 17.23% under pH 4.

Green Synthesis of Nickel Nanoparticles Using Salvadora persica and Their Application in Antimicrobial Activity against Oral Microbes

The current study evaluated the biogenic synthesis of nickel oxide nanoparticles (SP-NiONPs) from the root extract of (Salvadora persica) S. persica and their biological properties. The nanoparticles were characterized using spectroscopic and microscopic techniques and then evaluated for their antimicrobial properties against 10 oral pathogens. The ultraviolet-visible (UV–Vis) spectra exhibited a distinctive resonance spectrum at 334 nm for the SP-NiONPs produced from S. persica. The fourier transform infrared (FTIR) analysis revealed the presence of functional groups of biomolecules of S. persica that served as reducing and capping agents of the SP-NiONPs. The scanning electron microscope (SEM) and transmission electron microscopy (TEM) analyses showed that the nanoparticles were spherical-shaped, tightly packed, and ranged in size from 18.20 nm to 45.12 nm. The energy dispersive x-ray (EDX) analysis confirmed 69.9% of the nickel (Ni) content by weight, and the X-ray diffraction (XRD) results showed the face-centered cubic (FCC) crystalline structure of the formed SP-NiONPs. The antioxidant activity of the SP-NiONPs exhibited a dose-dependent profile with an IC50 value of 51.45 ± 0.65 and a 54.13 ± 0.98 DPPH• and ABTS•+ radical scavenging activity, respectively. The SP-NiONPs showed an antibacterial activity against all the test strains; however, E. cloacae was found to be the most sensitive strain, with an inhibition zone of 31 ± 0.50 mm. The SEM image of the E. cloacae cells treated with SP-NiONPs showed irregular shapes and ruptured, destroyed cell membranes. Our findings revealed that SP-NiONPs could be used as excellent antibacterial agents against oral pathogens.

Synthesis of nickel oxide nanoparticles from Enicostemma littorale plant extract and investigation of their photocatalytic and antimicrobial properties

Nickel oxide nanoparticles (NiOxi‐NPs) with a spherical shape have been developed using a green aqueous extract of the Enicostemma littorale plant, and their efficacy on various photochemical and biological applications like antibacterial and anticancer has been studied. The intense vibrational bands in the Fourier transformer infrared spectroscopy (FT‐IR) spectrum correspond to Ni‐O, C=O, and O‐H, confirming the formation of NiOxi‐NP. Also, two intense peaks at 2θ = 36.42° (111) and 42.87° (200) in the X‐ray diffraction (XRD) spectrum confirm the NiOxi‐NP crystal lattice as face center cubic (FCC). To determine the light‐absorbing behavior and shape of the newly produced NiOxi‐NP, UV‐visible, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) investigations were performed. NiOxi‐NP has a maximal distinctive UV‐visible absorption wavelength in the 306‐nm region. The nickel oxide nanoparticles are formed in spherical form and dispersed in the 33‐ to 46‐nm size range, according to the SEM and TEM investigations. According to the 3‐(4,5‐dimethyl thiazolyl‐2)‐2,5‐diphenyltetrazolium bromide (MTT) assay, the Michigan Cancer Foundation‐7 (MCF‐7) breast tumor cancer cell line is extremely responsive to the green NiOxi‐NPs' exceptional lethal effectiveness. The IC50 value for MCF‐7 cell lines is 12.87 μg/mL. When tested against bacteria such as Bacillus subtilis, Staphylococcus, and Escherichia coli stains, the aforementioned particles demonstrate greater activity on the three bacteria. The photocatalytic activity of the greenery NiOxi‐NP over the dye rhodamine B (RBD) was finished in 16 min when the solution concentration was 0.025 mg/L. The green synthesis of NiOxi‐NP nanoparticles can behave as a better UV‐visible screener between 290 and 450 nm, a better antimicrobial agent, a better RBD degradation agent, and a better low‐dose anticancer agent.

Green synthesis of cotton flower shaped nickel oxide nanoparticles: Anti-bacterial and tribological studies

The goal of this study was to synthesize nickel oxide nanoparticles (NiO-NPs) by the sol–gel method, which involved the use of Cassia Fistula is a herbal and medicinal plant. The Cassia Fistula (CF) plant extract acts as a stabilizing and capping agent. Further, NiO-NPs were characterized using UV–Visible spectroscopy (UV–Vis), Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX). According to the results of UV–Visible, the absorption spectroscopy has displayed that the band gap is 3.5 eV. The biological properties were studied for prepared NiO-NPs. The antibacterial testes were examined using different bacterial strains such as Escherichia coli, Staphylococcus aureus and Staphylococcus Epidermis and dose-dependent inhibition response was reported. The tribological tests are carried out using four ball testers in accordance with ASTM D4172-18 requirements. NiO-NPs are utilised as lubricating additives in poly alpha olefin (PAO4) base oil. NiO-NPs in PAO4 at a concentration of 0.5 wt% improved the coefficient of friction, and positive results are observed.

Synthesis and characterization of NiO nanoparticles using Sesbania grandiflora flower to evaluate cytotoxicity

Conventional nanoparticle (NP) synthesis based on physical and chemical processes are costly and are mostly associated with harmful effects on environment, whereas the use of plant extract is eco-friendly and cost effective which could act as reducing, stabilizing and capping agent. Herein, the present study is aimed to synthesize nickel oxide nanoparticles from nickel nitrate precursor and Sesbania grandiflora flower extract. Synthesized nickel oxide nanoparticles were characterized by Ultraviolet–Visible, FT-IR, SEM and XRD analyses. Ni-O stretching vibrations at 418 cm−1 in the FT-IR spectrum confirmed the formation of NiO NPs. The XRD pattern revealed the crystallite size of the NiO NPs to be in range of 19.9–60.4 nm. The morphology of the NiO NPs as revealed by the SEM images, which was rod like structure. The anticancer activity of the synthesized NiO NPs was evaluated with MM2 (human breast cancer cells) and HeLa (human cervical cancer cells) and compared with cisplatin. In MM2, the IC50 value of the NiO NPs is 33.57 ± 1.37 µg/mL whereas in HeLa, the IC50 value is 26.92 ± 1.67 µg/mL. The value is significant when compared with the conventional standard drug cisplatin (17.80 ± 0.30 µg/mL for MM2 and 15.06 ± 0.84 µg/mL for HeLa).

A green approach for the degradation of toxic textile dyes by nickel oxide (NiO-SD) NPs: Photocatalytic and kinetic approach

By utilizing the combustion process, nanoparticles can be produced quickly, easily, and in an environmentally friendly manner. In this study, sheep dung is employed as fuel for the synthesis of nickel oxide nanoparticles (NiO-SD), and characterization techniques such as XRD, FTIR, UV, FESEM, and EDX, are used to confirm the as-desired nanoparticles. Malachite green (MG) and methylene blue (MB), respectively, are used as benchmark dyes to measure the photocatalytic effectiveness of the material and systematically investigated the effects of the light source, dye concentration, dose of photocatalyst, and pH value on the effectiveness of photocatalyst and photodegradation kinetics. It is found that the NiO-SD, when exposed to UV light, shows good removal effectiveness of the MB and MG dyes, according to the photodegradation data of 99.9% and 96.8%, respectively. The remarkable photodegradation efficiency of MB and MG dyes over the developed photocatalyst is also explained by a plausible photo-catalytic process. The green-manufactured photocatalyst can be a promising for ecological applications such as waste-water remediation.

Biomedical Applications of Biosynthesized Nickel Oxide Nanoparticles.

Nickel oxide nanoparticles have gained tremendous attention recently in a variety of scientific domains thanks to their characteristic chemical, physical, optical, and biological properties. Due to the diversity of applications in various fields, different physicochemical methods have been used to synthesize nickel oxide nanoparticles. However, most conventional methods use hazardous chemicals during synthesis and become liable for potential health risks, while others are expensive and require a lot of energy to synthesize nanoparticles. As a result, the nanoparticles become less biocompatible and biologically inefficient. Biogenic synthesis of nanoparticles is currently proposed as a valuable alternative to the physical and chemical methods, as it is a simple, non-toxic, cheap, green and facile approach. This synthetic method uses biological substrates such as plant extracts, microorganisms, and other biological products to synthesize nickel oxide nanoparticles. The various phytochemicals from plant extracts, enzymes or proteins from microorganisms, and other biological derivatives play as reducing, stabilizing, and capping agents to provide bioactive and biocompatible nickel oxide nanoscale material. This review discusses current findings and trends in the biogenic synthesis of nickel oxide nanoparticles and their biological activities such as antibacterial, antifungal, antileishmanial, and anticancer, with an emphasis on antimicrobial and anticancer activity along with their mechanistic elucidation. Overall, this thorough study provides insight into the possibilities for the future development of green nickel oxide nanoparticles as therapeutic agents for a variety of ailments.

Green synthesis of Nickel Oxide Nanoparticles using Syzygium Aromatic Extract: Characterization and Biological Applications

In this study, nickel oxide (NiO) nanoparticles were successfully synthesized by Syzygium aromaticum (clove) extract via a green synthesis method and evaluated their antibacterial properties. The bio-molecules inside the extract play an important role in converting nickel nitrate salt into nickel oxide nanoparticles. The prepared nickel oxide nanoparticles were characterized via different techniques such as X-ray Diffraction, fourier transform infrared spectroscopy, field emission-scanning electron microscopy and ultraviolet-visible spectrophotometer. From X-ray diffraction results, the crystallite size of NiO NPs was estimated to be (39.7 nm). The fourier transform infrared spectroscopy exhibits intense two peaks at 594 cm-1 and 469 cm-1 which indicates the formation of NiO NPs. In addition, the energy band-gap calculated by Tauc’s formula was ~ 2.89 eV. Finally, The antibacterial activity study results detected that NiO NPs have the highest activity against Staphylococcus aureus when compared to Escherichia coli. Thus, the present study exhibits good antibacterial activity, which may be explored in future clinical treatments.

Green synthesis of Nickel Oxide Nanoparticles using Syzygium Aromatic Extract: Characterization and Biological Applications

Green synthesis of Nickel Oxide Nanoparticles using Syzygium Aromatic Extract: Characterization and Biological Applications

Isotherm, kinetics, thermodynamics, recyclability and mechanism of ultrasonic assisted adsorption of methylene blue and lead (II) ions using green synthesized nickel oxide nanoparticles

One of the urgent global problems demanding effective mitigation strategies is the pollution caused by organic dyes and metal ions like methylene blue and lead (II) ions. In recent times, the increasing applications of nickel oxide nanoparticles in biomedicine, catalysis, sensors in optoelectronic materials, and the prevention of environmental pollution have attracted researchers' interest across the globe. Herein, Psidium guajava leaves extract was utilized to synthesize green nickel oxide nanoparticles (PG-NiONPs). Surface and analytical techniques were employed to characterize PG-NiONPs and were thereafter applied to remove methylene blue and lead (II) ions from wastewater. The results revealed the quantified presence of phytochemicals such as alkaloids, phenols, tannins, flavonoids and saponins in the Psidium guajava leaves extract. The prepared PG-NiONPs revealed a crystalline phase, functional groups, mesoporous and microstructural arrangements typical of nickel oxide nanoparticles. The surface area of PG-NiONPs was obtained as 85.40 m2/g. The best ultrasonic-assisted adsorption of MB and Pb(II) ions was achieved at pH values of 6 and 5 for MB and Pb(II), a contact time of 60 min, an adsorbent mass of 40 mg/L, and a temperature of 50 °C, respectively. The maximum MB and Pb(II) adsorption capacities of 495.58 and 508.56 mg/g were evaluated. The experimental data corroborated with the pseudo-second-order and Toth isotherm models. The adsorption of MB and Pb(II) over green PG-NiONPs was a thermodynamically spontaneous process. The PG-NiONPs indicated good recyclability with high stability even after 8 adsorption cycles. Overall, the PG-NiONPs is a potential adsorbent for improved toxic dyes, metal ions and other scavengers removal from wastewater.