Performance Of Zinc Oxide Nanoparticles Research Articles

Remarkable photocatalytic performance of zinc oxide nanoparticles prepared through green synthetic method by using Citrus limon dry peel extract

Remarkable photocatalytic performance of zinc oxide nanoparticles prepared through green synthetic method by using Citrus limon dry peel extract

Gas Sensing Performance of Zinc Oxide Nanoparticles Fabricated via Ochradenus baccatus Leaf

ZnO nanoparticles (NPs) were prepared by green synthesis using plant leaf extraction of Ochradenus baccatus and characterized by XRD, FESEM, HRTEM, and Raman spectroscopy techniques. Since elevated CO levels have been associated with inflammatory conditions, cardiovascular diseases, and respiratory disorders and the methane gas primarily produced by gut microbiota and linked to gastrointestinal disorders and other abnormal methane levels in breath samples, the nanoparticles were applied for gas sensor fabrication. Thus, the gas sensors fabricated using ZnO nanoparticles were investigated for CH4, H2, CO, and NO2 gases. The gas sensing was performed for the fabricated sensors at various operating temperatures and gas concentrations. Interestingly, leaf-extracted green synthesized ZnO NPs were more sensitive to CH4, CO, and NO2 gases than to H2. The results of sensing studies revealed that the nanoparticles exhibit a selectivity toward gas depending on the gas type. The sensor response was also studied against the humidity. These findings bridge between the laboratory and industry sectors for future gas sensors development, which can be used for exhaled breath analysis and serve as potential diagnostic tools for highly sensitive contagious diseases.

Effect of ZnO Nanoparticles During the Process of Phytoremediation of Soil Contaminated with As and Pb Cultivated with Sunflower (Helianthus annuus L.)

Urbanization and industrialization have caused the production of pollutants in the soil, water, and air systems, negatively influencing plants, animals, humans, and the ecosystem. Heavy metals, such as arsenic (As), lead (Pb), cobalt (Co), chromium (Cr), mercury (Hg), and nickel (Ni), affect the development of organisms. In this study, as a novel alternative, the performance of zinc oxide nanoparticles (ZnO NPs) in sunflower plant growth (Helianthus annuus L.) and the decontamination of soils with As and Pb was investigated. For this purpose, in natural soil contaminated with As (0.02 mg kg of dry soil) and Pb (0.2 mg/kg of dry soil), sunflower plants were allowed to grow in pots for 25, 35, and 45 days after emergence. Morphological parameters were measured for the plants. The stems, leaves, and roots were dried (80 °C), ground, and finally, mineral analysis was performed by plasma atomic emission spectrometry (ICP). ZnO NPs were applied to the soil at two concentrations (0.3 and 0.6 mg/kg) and the control. ZnO NPs application resulted in plant growth and root length 25 days after emergence (DAE). The interaction between ZnO NPs and metals significantly negatively affected the variable root length. The roots, stems, and leaves accumulated metals at 25 and 45 DAE. Bioconcentration (BCF) and translocation (TF) factors were higher in Zn at 45 DAE. The phytoextraction by H. annuus assisted with ZnO NPs helps remediate polluted soils, potentiating the plant's hyperaccumulation characteristics. The results of this experiment offer basic information on the interaction of ZnO NPs in the phytoremediation process of soil contaminated with heavy metals. However, it is crucial to know the potential of NPs in soils with higher concentrations of contaminants in the soil, which we consider one of the limitations of this work, using low concentrations of heavy metals. Therefore, more research is required to corroborate the effectiveness of ZnO NPs in soils contaminated with Pb and Zn during the phytoremediation process with sunflower plants.Graphical

Synthesis, characterization, and photocatalytic application of silver doped zinc oxide nanoparticles

The advancement in nanotechnology has influenced the improvement in the photocatalytic performance of zinc oxide nanoparticles (ZnO NPs). The photocatalytic activities of ZnO are within irradiation wavelengths in the ultraviolet region and this hinders its efficiency in photocatalytic applications. Undoped and silver doped ZnO nanoparticles (Ag-doped ZnO NPs) were successfully prepared by co-precipitation technique at Ag doping concentrations of 0, 0.25, 0.5, 0.75, and 1 % to enhance the photocatalytic ability of ZnO NPs. The XRD results indicate a hexagonal wurtzite structure of the undoped and Ag-doped ZnO NPs with the estimated crystalline size ranges from 30.79, 23.72, 36.97, 21.49, and 25.66 nm, respectively, for ZnO at Ag doping concentrations. The SEM micrograph revealed the uniform distribution of Ag on the surface of ZnO NPs and a decrease in the size of the particle as concentration increases. The displacement in the absorption edge of ZnO to a higher wavelength led to narrowing the optical bandgap of ZnO due to Ag doping, as observed in the DRS spectra. Photocatalytic performance and photodegradation experiments were conducted using a model methylene blue (MB) dye contaminated in water. The dye concentration decreases as irradiation time increases in the presence of the photocatalyst with the improved performance of less exposure time and the highest dye degradation of about 98 %. It was revealed that the photocatalytic activity of ZnO toward MB degradation was effectively improved by Ag doping. Therefore, Ag doping of ZnO NPs had the synergetic effect of enhancing the photocatalytic activity of ZnO NPs.

Effect of synthesis methods on dielectric performance of ZnO nanoparticles

ABSTRACT Zinc oxide (ZnO) nanoparticles are widely studied for the application of dye-sensitised solar cells (DSSCs). The control of nanoscale morphology and microstructural properties of ZnO is critical for DSSCs performance. The current study provides an insight about the effect of synthesis methods (i.e. co-precipitation and sol–gel) on structural, optical and electrical properties of ZnO nanoparticles. The formation of hexagonal wurtzite phase with space group P63mc was confirmed by Rietveld fitted X-ray diffraction and Raman spectroscopy. The variation in morphology due to different synthesis methods was confirmed by Scanning electron microscopy. Functional groups were identified by Fourier transform infrared spectroscopy. The presence of defects led to the narrowing of band gap of ZnO nanoparticles, and was confirmed by diffuse reflectance spectroscopy. The frequency-dependent dielectric behaviour was explained by means of Maxwell–Wagner–Sillars model. The current study paves the way of potential application of ZnO nanoparticles in DSSCs.

UV-light photocatalytic degradation of non-ionic surfactants using ZnO nanoparticles

The aim of this study was to evaluate the performance of zinc oxide nanoparticles as a photocatalyst for photodegradation of two model non-ionic surfactants (Triton X-100 and C12E10). The first part of the investigation was focused on the synthesis and characterization of ZnO nanoparticles, since its crystalline structure strongly impacts its photocatalytic properties. Based on the results of the XRD analysis, it was concluded that the obtained material occurred in the form of hexagonal wurtzite with a polycrystalline structure. FT-IR and XPS analyses were used to elucidate and confirm the nanomaterial structure, whereas investigation of N2 adsorption/desorption and SEM/TEM imaging allowed to establish that the synthesized ZnO was characterized as a mesoporous material with uniform, spherical shape and particle size fluctuating between 90 and 130 nm. The second part of the study included spectrophotometric assessment of the photodegradation process. The use of the obtained ZnO nanoparticles allowed to achieve efficient photodegradation of both C12E10 (92%) and Triton X-100 (82%) after 1 h of UV irradiation. The Langmuir–Hinshelwood mechanism was used to describe the reaction kinetics. Subsequent LC-MS/MS analysis of the residues indicated that the degradation mechanism is most likely based on both central fission of the surfactant molecules with further terminal oxidation of poly(ethylene glycol) and terminal oxidation leading to carboxylic derivatives of surfactants.

Structure, Synthesis and Applications of ZnO Nanoparticles: A Review

Abstract: Nanotechnology deals with the creation and utilization of materials at a nanoscale. Nanoparticles, in general, possess enormous surface area per unit volume and have explicit characteristics. Zinc oxide (ZnO) - based nanomaterials have been recognized to be of countless uses for numerous important requests from the beginning of nanoscience as a result of the great quantity of zinc element and the comparatively simple adaptation of its oxide to nanostructures. Currently, ZnO as nanoparticles, nanowires, nanofibers in addition to other classy nanostructures occurs amongst the innovator nanomaterials utilized in solar cell systems, fuel cells, water purification and biomedical fields. ZnO nanoparticles had been a research target for many investigations because of their vast band-gap and extraordinary exciton binding energy. The performance of ZnO nanoparticles is completely different from those of corresponding bulk materials, through enhancing the properties and using lesser amount of materials, which leads to price reduction. The main purpose behind this review article is to give a deep view on structure, synthesis and applications of ZnO nanoparticles prepared through various approaches to give the reader a comprehensive understanding. Keywords: ZnO, Nanoparticles, Structure, Synthesis, Applications.

Application of Molybdenum oxide nanoparticles in H2S removal from natural gas under different operational and geometrical conditions

Microporous and nanoporous metal oxides are potential adsorbents for separating H2S from natural gas. Structured porous adsorbents have the potential to improve the energy and production costs in gas separation and catalysis applications by providing higher production rates. Zinc, Manganese, and Iron oxide nanoparticles are among the most potential and most extensively employed materials. Applying this framework, other novel metal oxides have been recognized for separation of H2S from representative H2S/CH4. In the present study, we investigate the performance of Molybdenum oxide nano-particles as an adsorbent for H2S removal and compare it with the performance of zinc oxide nano-particles. The effects of operating conditions such as temperature (65–89 °C), pressure (10–19 bar), initial concentration of H2S in the feed stream (38–73 ppm), and space velocity (0.018–0.045 m s−1) on H2S adsorption from sour gas are evaluated. Our analysis shows that Molybdenum oxide nano-particles have an adsorption capacity of 0.081 and 0.074 g H2S/g Molybdenum oxide in low temperature and low concentration of H2S using non-spherical and spherical Molybdenum oxide sorbent, respectively. Proceeding by two adsorption isotherms, the Langmuir and Freundlich isotherms, analysis of variance displayed that both models can fit the adsorption data of H2S on Molybdenum oxide nanoparticles very well, while the Freundlich isotherm seems to provide R2 value of 0.98–0.99, indicating a better prediction of our experimental data.

Sonocatalytic decolorization of methylene blue from aqueous media by La:ZnO/GO nanocomposites

The collaboration of graphene oxide and a rare earth element dopant has a significant effect on the catalytic performance of zinc oxide nanoparticles (ZnO). For this purpose, lanthanum-doped zinc oxide/graphene oxide (La:ZnO/GO) nanocomposites were produced. The La:ZnO/GO composites developed using various quantities of La3+ (3, 6 and 9 at.%) were used for methylene blue (MB) decomposition in the presence of ultrasound. SEM images of nanocomposites showed that the growth pattern of ZnO nanoparticles on the surface of graphene oxide changed, which can be related to lanthanum addition on the structure. In fact, by adding lanthanum, the structure of ZnO nanosheets that were aggregated in the flower form was converted into flower-like nanorods. TEM images clearly displayed La:ZnO/GO nanorods. The presence of lanthanum was confirmed by EDS analysis. La:ZnO(3 at.%)/GO nanocomposite, exhibited the highest sonocatalytic activity (93% after 80 min) and demonstrated good stability in optimized conditions (catalyst dosage 0.1 g, initial dye concentration 10 mg/L and irradiation time 80 min), which was checked out using response surface methodology from Design of Experiment software. After using a radical hydroxyl, superoxide and hole quencher results confirmed that the generated holes in the valence band of ZnO and superoxide radicals are major species for the MB oxidation process. The results demonstrated that the mineralization percentage of MB was approximately 93% of total organic carbon removal under ultrasound.

Abstract 857: Metal oxide nanoparticles as adjuvant for radiation therapy

Abstract Background: Radiation therapy comprises a fundamental component of modern tumor treatment. Unfortunately, its success is limited by the development of radiation resistances. The emerging field of nanotechnology offers great opportunities for diagnosing, imaging, as well as treating cancer. Metal oxide nanoparticles in particular zinc oxide nanoparticles (ZnO-NP) have been shown to display a selective cytotoxic effect on tumor cells via a yet unknown mechanism. Most likely the generation of reactive oxygen species (ROS), breakdown of mitochondria and DNA damage are involved. The success of radiation therapy equally relies on the generation of ROS, which develop their cytotoxic potential by damaging DNA, proteins and membranes in a fashion that exceeds the repair capacity of tumor cells. Thus, our aim was to evaluate the applicability of ZnO-NP as radiosensitizer to restore the response of tumor cells to radiation therapy. Methods: An AlamarBlueTM assay was used to evaluate the cellular metabolic activity (CMA) of A549 adenocarcinoma cells after treatment with ZnO-NP. To assess cellular viability and cell death a flow cytometric apoptosis assay was applied and genotoxicity of ZnO-NP was analysed by γH2AX foci analysis. The performance of ZnO-NP as radiosensitizer was assessed by a colony formation assay (CFA). Results: We were able to show that ZnO-NP-mediated cytotoxicity is conveyed by dissolved Zn2+ ions as well as by the particles themselves. Treatment with ZnO-NP resulted in double-strand breaks (DSB) of the DNA measured by γH2AX foci analysis. The apoptosis assay could show induction of apoptosis in A549 cells after treatment with 100 µg/ml ZnO-NP for four hours. The colony formation assay showed that irradiation with 2 or 4 Gray, according to dosages that are typically applied in clinical settings, in combination with ZnO-NP treatment could enhance tumor cell death and reduce clonogenic survival. This revealed that ZnO-NP could improve the success of radiation therapy. Conclusions: Our study proves that ZnO-NP exert a cytotoxic and genotoxic effect on human tumor cells. Additionally, we could show, that ZnO-NP are able to serve as radiosensitizer. Combined treatment of human tumor cells with ZnO-NP and irradiation resulted in reduction of tumor cell survival. Since nanoparticles can in principle be targeted selectively to tumor tissue, ZnO-NP could be used to specifically sensitize tumor cells for irradiation while sparing healthy tissue. All in all, the study shows that ZnO-NPs could be a promising antitumor agent. Citation Format: Nadine Wiesmann, Martin Kluenker, Wolfgang Tremel, Juergen Brieger. Metal oxide nanoparticles as adjuvant for radiation therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 857.

Reusability Performance of Zinc Oxide Nanoparticles for Photocatalytic Degradation of POME

Performance and reusability of different zinc oxide nanoparticles (ZnO-PVP and ZnO-PEG) for photocatalytic degradation of palm-mill oil effluent (POME) has been studied. The nanoparticles properties were characterised with fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM results show that ZnO-PEG nanoparticles exhibit the smaller size than ZnO-PVP with less agglomeration. It was found that ZnO-PEG shows better effectiveness than ZnO-PVP in reducing turbidity, colour and increasing the dissolved oxygen (DO). By using two types of reusability methods: (a) oven drying (b) hot water rinsing, the oven drying method portrayed the most efficient route for POME treatment. This research would be a solution to the palm oil industry for photocatalyst recovering as well as reduction of the chemical usage in order to meet the development of advanced and greener technologies.

Efficiency evaluation of the photocatalytic degradation of zinc oxide nanoparticles immobilized on modified zeolites in the removal of styrene vapor from air

Styrene monomer is a volatile organic compound that has many applications in plastics, rubber, and paint manufacturing industries. Exposure to styrene vapor has certain effects, including suppression of the central nervous system, loss of concentration, weakness and fatigue, and nausea and there is a possibility of carcinogenesis in long-term exposure. Therefore, it is necessary to control and eliminate this vapor. The aim of this study was to investigate the performance of zinc oxide nanoparticles on modified natural zeolites in removing styrene vapor from the air. Natural zeolites of clinoptilolite were modified using hydrochloric acid and diphenyldichlorosilane. Next, zinc oxide nanoparticles with different ratios of 3, 5, and 10 wt% were stabilized on the zeolites. To determine their characteristics, samples were used from BET, SEM and XRD analyses. The input styrene concentration and the ratio of nanoparticles stabilized on zeolites were studied as effective functional parameters on the removal process. The efficiency results of natural zeolites (Ze) and modified zeolites (Mze) in styrene adsorption from the air show that the styrene breakthrough in the bed of MZe compared to that of Ze increases approximately two times. Also, the results showed that the removal by the process of UV/MZe-ZnO 3%, UV/MZe-ZnO 5%, and UV/MZe-ZnO 10%, was 36.5%, 40%, and 26%, respectively. From the results it can be concluded that MZe can increase the efficiency of photocatalytic degradation. Clinoptilolites of Iran can be used as an adsorbent to remove polluted air in industries that have low concentrations and flow rates.

Performance of Zinc Oxide Nanoparticles as Polymerization Initiating Systems in the Microwave‐Assisted Synthesis of Poly(d,l‐Lactide)/ZnO Nanocomposites

Poly(D,L‐lactide) (PLA) is a biodegradable polymer widely used in medical applications, whose properties can be diversified by the incorporation of multifunctional nanoparticles. In this report, the microwave‐assisted ring‐opening polymerization of D,L‐lactide in the presence of ZnO nanoparticles was conducted to produce ZnO‐graft‐PLA nanocomposites. A comparative kinetic study of polymerization processes in mono‐modal and multi‐modal microwave reactors was addressed. Thanks to spectroscopic, thermal, and microscopic characterizations, the simultaneous formation of free PLA chains and grafted ones on ZnO nanoparticle surface was demonstrated, and the resulting products were carefully analyzed.