Presence Of ZnO Nanoparticles Research Articles

INVESTIGATING THE IMPLEMENTATION OF ZnO NANOPARTICLES AS A TUNABLE UV DETECTOR FOR DIFFERENT SKIN TYPES

A facile chemical reduction method was used to synthesize ZnO nanoparticles (NPs) in ethylene glycol solvent at two different calcination temperatures. As a result of variation in the calcination temperature, ZnO NPs with two different sizes were achieved. The NPs were investigated for their structural and optical characteristics using X-ray diffraction and ultraviolet (UV)–Vis spectroscopy. The synthesized ZnO NPs exhibited a hexagonal structure with sizes of 46 and 65[Formula: see text]nm. The synthesized NPs were then used to investigate dye photocatalytic behavior of products as a tunable UV detector for different skin types. The dye degradation and decolorization of methylene blue in the presence of ZnO NP, following UV radiation as a function of time, were studied at different pH levels. The optical absorption spectra were then taken every 15[Formula: see text]min for all samples. The UV–Vis spectroscopy spectra revealed that optical absorption of solution was decreased upon UV exposure as a function of time. Photocatalytic reaction indicated that the dye degradation and decolorization rate were accelerated with the increase of pH level. Therefore, a tunable UV detector for different skin types could be engineered by varying the pH level of solution to avoid human skin burning.

ZnO-nanoparticles as an Efficient Catalyst for the Synthesis of Functionalized Benzenes: Multicomponent Reactions of Sulfonoketenimides.

Functionalized benzenes are prepared from the reaction of sulfonoketenimides that is produced from the Copper catalyzed reaction of terminal alkynes and sulfonyl azides with zwitterionic intermediate that is generated from the reaction of dialkyl acetylenedicarboxylates, alkyl bromides and triphenylphosphine in the presence of ZnO-nanoparticles in good yields. All chemicals employed in this work were prepared from Fluka (Buchs, Switzerland) and were used without further purification. Nanoparticles of ZnO were synthesized according to literature report. Melting points were measured on an Electrothermal 9100 apparatus. Elemental analyses for C, H, and N were performed using a Heraeus CHN–O-Rapid analyzer. Mass spectra were recorded on a FINNIGAN-MAT 8430 spectrometer operating at an ionization potential of 70 eV. IR spectra were measured on a Shimadzu IR-460 spectrometer. 1H, and 13C NMR spectra were measured with a BRUKER DRX-500 AVANCE spectrometer at 500.1 and 125.8 MHz, respectively. In these reactions, the first step is optimization of reaction conditions for achieving best conditions. For this reason, solvent, catalyst, and reaction time is changed so that the best result is obtained. For optimization, several catalysts such as CuI, CuBr, CuCl, ZnO-nanoparticles, CM-ZnO, pyridine, piperidine, CuO-NPs, TiO2-NPs and copper powder were checked. Among them CuI and ZnO-NPs give the best results. Also, several solvents such as CH3CN, H2O, solvent-free conditions, toluene and diethyl ether are employed and CH3CN is the best solvent. In summary, sulfonoketenimides react with intermediate that is generated from the reaction of dialkyl acetylenedicarboxylate, alkyl bromides and triphenylphosphine in the presence of ZnO-NPs (10 mol%) to produce benzene derivatives in good yields.

Effect of Parthenium based vermicompost and zinc oxide nanoparticles on growth and yield of Arachis hypogaea L. in zinc deficient soil

Abstract Zinc is an important micro nutrient and is vital for germination, chlorophyll production, pollen function and fertilization. An investigation was carried out to explain the effect of Parthenium based vermicompost and nanoparticles (zinc oxide nanoparticles) on the growth profile and yield of Arachis hypogaea L. in zinc deficient soil. Parthenium mediated zinc oxide nanoparticle and zinc sulphate treated seeds were cultivated in zinc deficient soil. Presence of zinc oxide nanoparticles in the treated seeds were confirmed through atomic absorption spectroscopy. Various growth and yield related parameters, including fresh weight, dry weight, shoot length, root length, chlorophyll content, total free phenols, reducing sugar and total soluble sugar, number of pods etc. was positively affected by the nanoparticle treatment. Chlorophyll as well as total free phenols, reducing sugar and total soluble sugar levels were increased up to 300 ppm of zinc oxide nanoparticles treatments. Zinc oxide nanoparticle treatment increased the number of pods per plant when compared to control treatment. Best increase in pods and grains yield was recorded at 300 ppm of zinc oxide nanoparticle treatment. Zinc oxide nanoparticles were used as fertilizer for zinc deficient soil. The uses of nanoparticles in agriculture may be enhancing the crop production in deficient soil.

Green Synthesis of Pyrido[2,1-a]isoquinolines and Pyrido[1,2-a]quinolines by Using ZnO Nanoparticles

Pyrido[2,1-a]isoquinoline and pyrido[1,2-a]quinoline derivatives have been produced in good yields by the reaction of isoquinoline or quinoline, activated acetylenic compounds, α-halo ketones, and triphenylphosphine in the presence of ZnO nanoparticles (NPs) as an efficient catalyst under solvent-free conditions at room temperature. The reaction workup is easy, and the products can be readily separated from the reaction mixture. ZnO NPs markedly improved the yield of the product. The catalyst showed significant reusable activity.

Polyaniline/zinc oxide nanocomposite as room‐temperature sensing layer for methane

Methane detection in ambient condition has become essential as it is being increasingly used as compressed natural gas in many industrial processes and for domestic and transportation purposes. Hence, in this work, we report a room‐temperature methane sensor based on polyaniline/zinc oxide (PANI/ZnO) nanocomposite. The PANI/ZnO nanocomposite was prepared by chemical polymerization of aniline in the presence of ZnO nanoparticles. Electron microscopy results revealed the successful formation of nanocomposites with rod‐like ZnO nanoparticles embedded into the network of nanofibrillar PANI matrix. The PANI/ZnO nanocomposites exhibited a high response to methane at room temperature within a short response time of 20 s for a methane concentration (500 ppm) much lower than its flammability limit. Moreover, the humidity dependence of the sensor response was found to be very low. POLYM. ENG. SCI., 58:1438–1445, 2018. © 2017 Society of Plastics Engineers

Regioselective synthesis and theoretical studies of novel bis(tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8(4H)-ones) catalyzed by ZnO nanoparticles

A novel series of bis(tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8(4H)-ones) were prepared in a regioselective manner via a three component reaction of bis-aldehydes with 5-amino-1,2,4-triazole and dimedone under microwave irradiation as well as under conventional heating. The reactions were carried out in the absence as well as in the presence of ZnO nanoparticles as a heterogeneous catalyst. Best results were achieved when these reactions were carried out under MW heating. The presence of ZnO nanoparticles was found to improve the yields of the reactions but did not change the regioselectivity the products. The reaction mechanism and the unambiguous structural elucidation of the expected regioisomers were studied using DFT calculations as well as 2D-HMBC spectroscopy.

Supplementing zinc oxide nanoparticles to cryopreservation medium minimizes the freeze-thaw-induced damage to spermatozoa

The sperm DNA integrity post cryopreservation of human semen samples is one of the serious concerns in human infertility treatment. In the present study, the beneficial effects of zinc oxide nanoparticles in preserving the functional ability of spermatozoa was explored. Ejaculates of normozoospermic men cryopreserved along with Zinc oxide nanoparticles (ZnONPs) exhibited non-significantly higher percentage of total and progressive motility in frozen-thawed samples compared to control. The sperm chromatin damage and malondialdehyde (MDA) level was significantly lower in ZnONPs group (P < 0.01 and P < 0.05 respectively) and the spermatozoa's ability to undergo acrosome reaction was also unaltered. Fluorescence microscopy and High resolution transmission electron microscopy analysis demonstrated that the ZnONPs do not penetrate the membrane of spermatozoa but stay around the spermatozoa. In conclusion, the presence of ZnONPs during cryopreservation appears to be beneficial to the spermatozoa as they withstand freeze-thaw process competently better than control, without any adverse effect shown.

Effect of Pre-Annealing on Thermal and Optical Properties of ZnO and Al–ZnO Thin Films

Zinc oxide (ZnO) nanoparticles were synthesized by a simple solution route method using zinc acetate as the precursor and ethanol as the solvent. At a temperature of 60[Formula: see text]C, a clear homogenous solution is heated to 100[Formula: see text]C for ethanol evaporation. Then the obtained precursor powder is annealed at 600[Formula: see text]C for the formation of ZnO nanocrystalline structure. Doped ZnO particle is also prepared by using aluminum nitrate nonahydrate to produce aluminum (Al)-doped nanoparticles using the same solution route method followed by annealing. Thin film fabrication is done by air evaporation method using the polymer polyvinyl alcohol (PVA). To analyze the optical and thermal properties for undoped and doped ZnO nanocrystalline thin film by precursor annealing, characterizations such as UV, FTIR, AFM, TGA/DTA, XRD, EDAX and Photoluminescence (PL) were also taken. It was evident that precursor annealing had great influence on thermal and optical properties of thin films while ZnO and AZO film showed low crystallinity and intensity than in the powder form. TGA/DTA suggests pre-annealing effect improves the thermal stability, which ensures that Al ZnO nanoparticle can withstand at high temperature too which is the crucial advantage in the semiconductor devices. UV spectroscopy confirmed the presence of ZnO nanoparticles in the thin film by an absorbance peak observed at 359[Formula: see text]nm with an energy bandgap of 3.4[Formula: see text]eV. A peak obtained at 301[Formula: see text]nm with an energy bandgap of 4.12[Formula: see text]eV shows a blue shift due to the presence of Al-doped ZnO nanoparticles. Both ZnO and AZO bandgap increased due to precursor annealing. In this research, PL spectrum is also studied in order to determine the optical property of the nanoparticle embedded thin film. From PL spectrum, it is observed that the intensity of the doped ZnO is much more enhanced as the dopant concentration is increased to 1[Formula: see text]wt.% and 2[Formula: see text]wt.% of Al in ZnO.

The Heterophase Polymerisation of Styrene in the Presence of Zinc Oxide Nanoparticles

Heterophase polymerisation of styrene was carried out, and nanocomposite polystyrene microspheres with a controllable content of ZnO nanoparticles were synthesised. The colloid chemical properties of the obtained polymer suspensions were studied, and it was shown that the particles have a ‘core–shell’ structure with a ZnO content of up to 30%.

ZnO-nanoparticles as an efficient catalyst for the synthesis of tetrasubstituted cyclopentadienones using sulfonoketenimides and enaminoesters

A convenient and efficient approach to the synthesis of substituted cyclopentadienes is reported based on the reaction of sulfonoketenimides and enaminoesters in good yield. In these reactions, sulfonoketenimides is produced from the reaction of terminal alkynes and sulfonyl azides in the presence of copper iodide and enaminoesters is prepared via the reaction of dialkyl acetylenedicarboxylates and primary amines in the presence of ZnO-nanoparticles.

Novel hybrid nanofluid with tunable specific heat and thermal conductivity: Characterization and performance assessment for energy related applications

The utilization of heat transfer fluids with improved specific heat and thermal conductivity will be beneficial for enhanced energy collection in solar thermal systems. Accordingly, hybrid nanofluids comprising ZnO nanoparticles and encapsulated paraffin wax in propylene glycol-water mixture were prepared and characterized. The influence of encapsulated paraffin wax concentration (4–16 wt. %) and ZnO nanoparticle concentration (0–2 vol %) revealed that the thermal conductivity and specific heat could be improved to a maximum of 10.4% and 18.7% respectively, in comparison with those of propylene glycol-water mixture, at their appropriate concentrations. The presence of ZnO nanoparticles was found to influence the phase change characteristics of encapsulated paraffin wax, in such a way that the latent heat due to phase change was increased at an optimum concentration of ZnO nanoparticle concentration. While the maximum enhancement in overall heat transfer coefficient of 15.37% was obtained for the hybrid nanofluid sample that had both thermal conductivity and specific heat higher than the base fluid, the maximum enhancement in heat transfer rate (13.54%) was obtained for the hybrid nanofluid that had 18.65% enhancement in specific heat. The results of present investigation reveal the potential of hybrid nanofluids for energy management.

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.

Concrete columns reinforced with Zinc Oxide nanoparticles subjected to electric field: buckling analysis

As concrete is most usable material in construction industry it\'s been required to improve its quality. Nowadays, nanotechnology offers the possibility of great advances in construction. In this study, buckling of horizontal concrete columns reinforced with Zinc Oxide (ZnO) nanoparticles is analyzed. Due to the presence of ZnO nanoparticles which have piezoelectric properties, the structure is subjected to electric field for intelligent control. The Column is located in foundation with vertical springs and shear modulus constants. Sinusoidal shear deformation beam theory (SSDBT) is applied to model the structure mathematically. Micro-electro-mechanic model is utilized for obtaining the equivalent properties of system. Using the nonlinear stress-strain relation, energy method and Hamilton\'s principal, the motion equations are derived. The buckling load of the column is calculated by Difference quadrature method (DQM). The aim of this study is presenting a mathematical model to obtain the buckling load of structure as well as investigating the effect of nanotechnology and electric filed on the buckling behavior of structure. The results indicate that the negative external voltage applied to the structure, increases the stiffness and the buckling load of column. In addition, reinforcing the structure by ZnO nanoparticles, the buckling load of column is increased.

Changes in nutrient removal and flocs characteristics generated by presence of ZnO nanoparticles in activated sludge process

The aim of this work was to evaluate the impact generated by ZnO NPs on the activated sludge process treating raw (RWW) and filtered wastewater (FWW). It was analyzed the oxygen uptake rate, nutrient removal, flocs characteristics and the morphological interactions between activated sludge and ZnO NPs, in presence of 450–2000 mg/L. The results showed that the presence of more than 450 mg/L of ZnO NPs in raw and filtered wastewater inhibited the oxygen uptake by activated sludge. The highest inhibition was 35% in presence of 1500 mg/L in RWW. The organic matter removal was only inhibited in the presence of 450 and 900 mg/L of ZnO NPs; while ammonia removal decreased for all concentrations of ZnO NPs in both types of wastewater, around 13% for RWW and up to 9% for FWW. The orthophosphate removal improved as the concentration of ZnO NPs increased for both wastewater types, enhancing up to 8% for RWW and 17% for FWW. The flocs size of activated sludge exposed to ZnO NPs in RWW decreased as the concentration of ZnO NPs increased; while for FWW, an opposite effect was observed. The elemental mapping allowed detect the Zn inside of microorganisms, which may correspond to a toxicity mechanism in RWW and FWW. These results indicated that the changes in nutrient removal and flocs characteristics caused by the presence of ZnO NPs on the activated sludge are related to wastewater characteristics, such as suspended solids, type of substrate and concentration of ZnO NPs.

Spectroscopic characterization and docking studies of ZnO nanoparticle modified with BSA

Nanoparticles (NP) into a biological environment are an interesting topic for diagnosis and therapy in applications for medicine or environment and the knowledge about this interaction is important from the perspective of safe use of nanomaterials. In the current study, we characterized the type of interaction and the orientation of bovine serum albumin (BSA) adsorbed on ZnO nanoparticle surfaces as a function of size, using molecular docking. To probe experimentally different theoretical hypothesis about the interaction, ZnO-NPs were prepared in aqueous solution, and then were bioconjugated with BSA. Transmission electron microscopy (TEM) and Raman spectroscopy confirm the spherical shape of NP and the irreversible adsorption of BSA on NP surface. Raman and Infrared spectroscopy (FTIR) reveal that BSA interaction with ZnO nanoparticle produced a conformational rearrangement into protein, observing changes in Tyr and Trp environment, a minor percentage of α-helix structure and a more extended chain. The fluorescence analysis demonstrated that when BSA concentration higher than 30μM is used the signal due to the self-oligomerization of protein overlaps with the ZnO nanoparticle emission. The results predicted that the most probable interaction site is near to domain IB and IIA and ionic interactions are the major responsible for the binding. Thermal stability studies reveals that the denaturalization temperature of BSA increase from 57°C to 65°C in presence of ZnO NP and their esterase-like activity was improved.

Hydrodynamic performance of a pulsed extraction column containing ZnO nanoparticles: Drop size and size distribution

This article concerns the influence of different ZnO nanoparticle concentrations (0.001, 0.003, 0.005 and 0.01wt%) along with operating parameters (i.e., pulsation intensity and flow rate of dispersed and continuous phases) and physical properties on mean drop size and drop size distribution in a horizontal pulsed perforated-plate extraction column for the toluene–acetone–water and butyl acetate–acetone–water systems (mass transfer direction from the dispersed phase to the continuous phase). According to the results, it is observed that the addition of nanoparticles has a remarkable influence on breakage and coalescence of drops and consequently their size distribution. Accordingly, adding nanoparticles reduces the interfacial tension due to internal turbulence caused by nanoparticles’ Brownian motion inside each drop. It is found that drop size distribution will shift to the left and the density of small droplets will increase in the presence of ZnO nanoparticles in the column. Furthermore, new correlation is proposed to predict mean drop size in terms of operating parameters, physical properties and nanoparticle concentration. It is also found that the maximum entropy principle is suitable to predict drop size distribution in a horizontal extraction column.

Solar Photocatalytic Degradation of Methylene Blue by ZnO Nanoparticles.

The scalable and economical synthesis approach of ZnO has always been demanded, since it is very useful material in the degradation of hazardous dyes. Herein, a scalable synthesis approach for ZnO nanoparticles by precipitating the precursors such as zinc sulphate heptahydrate and ammonium hydroxide has been proposed. Calcinations at suitable temperatures can improve crystalline nature of materials. Therefore as-synthesized ZnO nanoparticles were calcinated at different temperatures 400 °C, 650 °C, 900 °C, 1150 °C, and subsequently their physical and morphological properties were characterized. The TEM analysis revealed the morphology, whereas XRD and SAED confirmed the purity and crystalline nature of ZnO. Moreover, photo catalytic degradation/adsorption results for methylene blue dye of lower (2.5 ppm) and higher concentrations (5 ppm) in the presence and absence of sunlight and ZnO nanoparticles are also reported. Addition of ZnO nanoparticles to methylene blue resulted in enhanced rate of photo degradation in the presence of sunlight. The complete photodegradation of 2.5 and 5 ppm methylene blue in sunlight occurred in 90 min and 165 min, respectively in presence of ZnO nanoparticles. In general many photocatalytic degradation studies had been reported using an artificial light source; however in the present work direct sunlight has been utilized.

Green Synthesis of Zinc Oxide Nanoparticle Using Green Tea Leaf Extract for Supercapacitor Application

The advancement of green chemistry in the synthesis of nanoparticles with the use of plants and its parts has become a great attention today. The nanoparticles of metals and metal oxides with green synthesis have reputation on recent developments. Products from nature or that resultant from natural products, such as extracts of various parts of plants have been used as reductions and as ceiling agents during synthesis. In our work, we have chosen green tea leaves(Camellia sinensis) for the Green synthesis of Zinc oxide nanoparticles (ZnO Nps). The formation of nanoparticles was observed by visualizing color changes and it was confirmed by Scanning Electron Microscope (SEM), UV-Vis spectrophotometer and Fourier Transform Infra-Red (FT-IR) spectrophotometer. The results of various techniques confirmed the presence of Zinc oxide nanoparticles. The UV-Vis spectrum was recorded to observe the absorption spectra, which exhibited a blue shift absorption peak at 338 nm. The XRD pattern revealed well-defined peaks appearing at 2θ positions corresponding to the hexagonal wurtzite structure of ZnO nanoparticles. The average size of the nanoparticles calculated using XRD data was 54.84 nm, the band gap energy was 3.40eV. FT-IR spectra were recorded for the as prepared nanoparticle to identify the biomolecules involved in the synthesis process. The higher percentage of phenolic compounds, with antioxidant potential, acts as the reducing agent on the metal oxides and significantly present amino acid, protein and lipids helped to control the growth of the nanoparticles. CV study shows an excellent capacitance behaviour, low equivalent series resistance (ESR) and fast diffusion of electrolyte ions into the composite. This confirms that the as-prepared ZnO material is the best suitable material for supercapacitor applications.

Biodesulfurization of Dibenzothiophene by Two Bacterial Strains in Cooperation with Fe3O4, ZnO and CuO Nanoparticles

Fossil fuels contain a considerable amount of sulphur which after burning will have negative effects such as generating acid rain in the environment. Biodesulfurization is assumed to be a promising process for desulfurization due to no need for extreme conditions and furthermore breaking the C-S bond by microorganisms without destruction of the heterocyclic structure, through a pathway called 4S. In this study dibenzothiophene (DBT), as a model target compound was applied for sulfur removal by a cooperative system of two bacterial strains; Rhodococcus erythropolis IGTS8 and Pseudomonas aeruginosa PTSOX4, and Fe3O4, ZnO and CuO nanoparticles. Results of spectrophotometry and further HPLC analysis demonstrated that addition of the ZnO nanoparticles into the microbial culture, significantly resulted in the increment of desulfurization rate and conversion of DBT to 2-hydroxybiphenyl. The maximum value of almost 1.4 fold improvement in biodesulfurization activity was obtained for P. aeroginusa PTSOX4 in the presence of ZnO nanoparticles.

Cytotoxicity, oxidative stress and inflammation induced by ZnO nanoparticles in endothelial cells: interaction with palmitate or lipopolysaccharide.

Recent studies showed that ZnO nanoparticles (NPs) might induce the toxicity to human endothelial cells. However, little is known about the interaction between ZnO NPs and circulatory components, which is likely to occur when NPs enter the blood. In this study, we evaluated ZnO NP-induced cytotoxicity, oxidative stress and inflammation in human umbilical vein endothelial cells (HUVECs), with the emphasis on the interaction with palmitate (PA) or lipopolysaccharide (LPS), because PA and LPS are normal components in human blood that increase in metabolic diseases. Overall, ZnO NPs induced cytotoxicity and intracellular reactive oxygen species (ROS) at a concentration of 32 μg ml-1 , but did not significantly affect the release of inflammatory cytokines or adhesion of THP-1 monocytes to HUVECs. In addition, exposure to ZnO NPs dose-dependently promoted intracellular Zn ions in HUVECs. PA and LPS have different effects. Two hundred μm PA significantly induced cytotoxicity and THP-1 monocyte adhesion, but did not affect ROS or release of inflammatory cytokines. In contrast, 1 μg ml-1 LPS significantly induced ROS, release of inflammatory cytokines and THP-1 monocyte adhesion, but not cytotoxicity. The presence of ZnO NPs did not significantly affect the toxicity induced by PA or LPS. In addition, the accumulation of Zn ions after ZnO NP exposure was not significantly affected by the presence of PA or LPS. We concluded that there was no interaction between ZnO NPs and PA or LPS on toxicity to HUVECs in vitro. Copyright © 2016 John Wiley & Sons, Ltd.