Concentrations Of CuO Nanoparticles Research Articles

Development of a new tool for the long term in vitro ecotoxicity testing of nanomaterials using a rainbow-trout cell line (RTL-W1)

The current wide use of manufactured nanomaterials (MNs) is leading to the release of nanoparticles (NPs) to water bodies. Aquatic organisms, including fish, are exposed to low concentrations of NPs for long periods of time being necessary to develop laboratory toxicity tests reflecting realistic conditions. Additionally, today there is a demand of in vitro assays respecting the 3Rs principle. Thus, the main aim of this work was to stablish an in vitro tool for the assessment of long-term NPs ecotoxicity. Considering the key role of liver in detoxification, a rainbow trout liver cell line, RTL-W1, was used. CuO NPs were chosen to validate this tool taking into account their important production level. Cells were exposed for 21 days to 25 or 100 μg CuO NPs/ml. Every seven days cells were split and one fourth of them transferred to a new plate with appropriate concentrations of NPs in culture medium. Lower concentrations of CuO NPs did not cause any deleterious effect, whereas higher concentrations led to significant mortality after 14 days and to the intracellular accumulation of Cu particles. Identical results were observed in cells exposed to CuSO4 at the same Cu concentrations. Therefore, the observed toxic effects might be mainly due to Cu2+ ions.

Effect of temperature and CuO-nanoparticle concentration on the thermal conductivity and viscosity of an organic phase-change material

The main results of an experimental study of the effect of temperature and nanoparticle concentration on thermal conductivity and viscosity of a nanofluid are shown. The nanofluid was prepared with Octadecane, an alkane hydrocarbon with the chemical formula CH3(CH2)16CH3, as a base fluid and 75-nm CuO spherical nanoparticles. Since the base fluid is a phase change material (PCM) to be used in thermal storage applications, the engineered nanofluid is referred to as Nano-PCM. Three Nano-PCMs were prepared by the two-step method (2.5% w/v, 5.0% w/v, and 10.0% w/v). In order to increase the stability of the Nano-PCM, the surface of the CuO nanoparticles were modified with Sodium oleate, and it was verified by IR analysis. The modified CuO nanoparticles were dispersed with an ultrasonic horn. The thermal conductivity was measured with a thermal properties analyzer in the temperature range of 30–40 °C. The viscosity was measured in the temperature range of 30–55 °C. The results for the Nano-PCM showed that thermal conductivity is almost constant in the analyzed temperature range, and the viscosity decreases non-linearly with temperature. With respect to the effect of nanoparticle concentration, both thermal conductivity and viscosity increased with nanoparticle concentration. Thermal conductivity increased up to 9% with respect to the base fluid, and viscosity increased up to 60%, in both cases with increasing concentration. Finally, the viscosity measurements for different deformation rates (30–80 RPM) showed that the addition of nanoparticles modifies the rheological behavior of the base fluid, from a Newtonian to a shear thinning (power-law) non-Newtonian behavior.

Toxicity of Copper Oxide (CuO) Nanoparticles on Human Blood Lymphocytes.

CuO nanoparticles (CuO-NPs) serve several important functions in human life, particularly in the fields of medicine, engineering, and technology. These nanoparticles have been utilized as catalysts, semiconductors, sensors, gaseous and solid ceramic pigments, and magnet rotatable devices. Further use for CuO-NPs has been employed in the pharmaceutical industry especially in the production of anti-microbial fabric treatments or prevention of infections caused by Escherichia coli and methicillin-resistant Staphylococcus aureus. Two key potential routes of exposure to CuO-NPs exist through inhalation and skin exposure. Toxicity of these nanoparticles has been reported in various studies; however, no study as of yet has investigated the complete cellular mechanisms involved in CuO-NPs toxicity on human cells. The aim of this study was to determine the cytotoxicity of CuO-NPs on human blood lymphocytes. Blood lymphocytes were obtained from healthy male subjects through the use of Ficoll polysaccharide subsequently by gradient centrifugation. The following parameters were assayed in blood lymphocytes after a 6-h incubation with different concentrations of CuO-NPs: cell viability, reactive oxygen species (ROS) formation, lipid peroxidation, cellular glutathione levels, and mitochondrial and lysosomal damage. Our results demonstrate that CuO-NPs, in particular, decreased cell viability in a concentration-dependent manner and the IC50 determined was 382μM. CuO-NP cytotoxicity was associated with significant increase at intracellular ROS level and loss of mitochondrial membrane potential and lysosomal membrane leakiness. Hence, CuO-NPs are shown to effectively induce oxidative stress in addition to inflict damage on mitochondria and lysosomes in human blood lymphocytes.

Experimental study of the thermal conductivity features of the water based Fe3O4/CuO nanofluid

The properties of thermal conductivity of water based Fe3O4/CuO nanofluid with respect to different parameters such as temperature and weight percent of forming nanoparticles were empirically investigated. The thermal conductivity was measured using hot wire method. According to the results, the thermal conductivity of the Fe3O4 nanofluid in the presence of different concentrations of CuO nanoparticles increases significantly. A linear relationship between increasing the concentrations of CuO nanoparticles and the growth of thermal conductivity of Fe3O4 nanofluid in the temperature range of 25 to 50 °C was observed.

Elicitation of Secondary Metabolites in Callus Cultures of Stevia rebaudiana Bertoni Grown Under ZnO and CuO Nanoparticles Stress

Accumulation of secondary metabolites in medicinal plants by giving abiotic/biotic stress is, nowadays, an active area of research. This study reports the inoculation of ZnO and CuO nanoparticles in Murashige and Skoog (MS) medium having plant growth regulators for the regeneration of callus from leaf explants of medicinal plant, Stevia rebaudiana. Presence of ZnO and CuO nanoparticles in different concentrations results in conferring different kinds of physiology in different regenerants. 1 and 10 mg/L have been declared the best ZnO and CuO nanoparticles concentrations regarding various physiological parameters. Steviol glycosides have not been detected in any callus treatment. Moreover, the phytochemical characteristics of S. rebaudiana under different ZnO and CuO nanoparticles concentrations have been exploited. The highest amount of total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity has been obtained at 100 mg/L of ZnO nanoparticles, whereas TPC, TAC, TRP and DPPH free radical scavenging activity have been achieved highest at 10 mg/L concentration of CuO nanoparticles. However, the highest TRP in the context of ZnO and the highest TFC regarding CuO have been achieved at 50 and 100 mg/L, respectively. This clearly indicates that CuO nanoparticles are more toxic to Stevia callus as compared to ZnO nanoparticles, and opens avenues for future studies utilizing ZnO or CuO nanoparticles for the enhancement of commercially important secondary metabolites in different medicinal plants.

Nanorefrigerants for energy efficient refrigeration systems

Nanorefrigerants, which are a new class of nanofluids, are mixtures of nanoparticles and refrigerants. They have several potential applications in various fields, such as for refrigeration and air-conditioning systems and heat pumps, among others. Accordingly, adding nanoparticles to conventional refrigerants results in anomalous improvements in the thermophysical properties and heat transfer characteristics of refrigerants, thereby further improving the performance of refrigeration systems. In the present study, R134a-based nanorefrigerant from R134a + CuO/Polyalkylene glycol (PAG) oil nanolubricant was prepared by dispersing copper oxide nanoparticles in the PAG lubricant. The effect of adding nanoparticles was investigated in relation to the thermal conductivity of lubricants and tribological characteristics of nanolubricants. The overall performance of a vapor compression refrigeration system with nanorefrigerants was evaluated. Enhanced heat transfer rate, coefficient of performance, freezing capacity, and reduced power consumption were observed for the refrigeration system. The thermal conductivity of the nanolubricant was better than that of the pure lubricant. Experimental results also showed that the low concentrations of CuO nanoparticles suspended in synthetic oil enhanced the tribological properties of the base oil.

Experimental investigation of heat transfer enhancement in helical coil heat exchangers using water based CuO nanofluid

The present work deals with the study of heat transfer enhancement using water based CuO nanofluids in the helical coil heat exchanger. Nanofluids were prepared using two-step method by using wet chemical method. Nanofluids with various volume percentage between 0 and 0.5 of CuO nanoparticles and their flow rate between 30 and 80 LPH (Reynolds number ranging from 812 to 1895, Laminar flow regime) were considered in the present study. The setup consists of a test section (helical coil), cooler, reservoir, pump, flow meter, thermocouples and flow controlling system. The temperature measurements were carried out with the help of thermocouples. The investigation was carried out to study the effect of particle loading and flow rate on heat transfer coefficient and Nusselt number. It has been found that the increase in the loading of CuO nanoparticles in base fluid shows a significant enhancement in the heat transfer coefficient of nanofluid. In the present study, at 0.1vol% concentration of CuO nanoparticles in nanofluid, enhancement in heat transfer coefficient was 37.3% as compared to base fluid while at 0.5vol%, it is as high as 77.7%. Also with the increase in the flow rate of the CuO nanofluid, significant increase in heat transfer coefficient was observed.

Time-Dependent Toxicity Responses in Daphnia magna Exposed to CuO and ZnO Nanoparticles.

Aggregation and dissolution of CuO and ZnO nanoparticles (NPs) increased with increasing exposure time (24, 48, and 72h). Acute toxicity of CuO NPs to Daphnia magna also increased significantly with increasing exposure time (p < 0.05), whereas exposure time did not significantly affect acute toxicity of ZnO NPs. The dissolved Cu concentration of CuO NPs was much lower than the median effective concentration (EC50) value (44μgL-1 at 72h), implying that the increase in acute toxicity was caused by particles rather than by dissolved ions. However, the dissolved Zn concentration of ZnO NPs was higher than the EC50 value (600μgL-1 at 72h), suggesting this acute toxicity may be caused by dissolved ions. Moreover, CuO NPs induced greater lipid peroxidation than Cu ions did at an exposure time of 72h, whereas converse results were observed for ZnO NPs.

Preparation and characterization of copper oxide nanoparticles and determination of enhancement in critical heat flux

The main focus of the present work is to prepare the CuO nanoparticles by economical Sol-Gel method and further to prepare the CuO nanofluid with base fluid as deionised water. The size of nanoparticles is determined by Debye- Scherer formula and size of the particles is conformed 20.4054nm. Critical heat flux characteristics of nanofluid were investigated with different weight concentrations of CuO nanoparticles. The experimental work revealed an increase in critical heat flux value just about 57.26 percent. Surface roughness of heater surface is measured for all weight concentrations of nanofluid which shows increase in Ra value up to some extent is a cause to enhance CHF.

Numerical and statistical study on melting of nanoparticle enhanced phase change material in a shell-and-tube thermal energy storage system

This paper presents a numerical and statistical study on heat transfer and energy storage performance of a vertical shell and tube thermal energy storage unit, where CuO – water nanofluid is used as heat transfer fluid (HTF) in the tube and CuO – paraffin nanoparticle enhanced phase change material (NePCM) is used on the shell side for latent thermal energy storage. A computational fluid dynamics (CFD) model is developed to simulate the laminar nanofluid flow, melting of NePCM and the overall heat transfer between the HTF and NePCM, where an enthalpy porosity technique is used in modeling the melting process. With this numerical model, the response surface methodology (RSM) is applied to statistically investigate the effects of three main operational parameters on the NePCM melting process: (1) concentration of CuO nanoparticles in the HTF, with a range of 0–4vol.%; (2) concentration of CuO nanoparticles in the NePCM, with a range of 0–7vol.%; and (3) inlet temperature of the HTF. Thermophysical properties of the NePCM are considered to be temperature dependent in the analysis. Face-centered central composite design (CCF) is employed to find the significant factors and their interactions in affecting liquid fraction rate in the melting process. It is found that changes in all these three factors are responsible for 99.8% liquid fraction variation, with HTF inlet temperature as the most significant parameter. Moreover, all three factors show a parabolic behavior on the liquid fraction variation. Finally, a regression model is developed for prediction of liquid fraction in the NePCM.

Thermal energy storage enhancement of a binary molten salt via in-situ produced nanoparticles

Thermal energy storage (TES) system is an essential component of any concentrating solar thermal power (CSP) plant to ensure a reliable plant operation even at night or cloudy weather. To enhance the TES capacity, a one-step method was proposed to synthesize nano-salts by in-situ production of CuO nanoparticles, via a high temperature decomposition of copper oxalate, in a binary salt used as a phase change material (PCM). The specific heat of the nano-salt both for solid and liquid phases were measured by differential scanning calorimetry (DSC) with the weight fraction of CuO nanoparticles varied from 0.1 to 3.0wt%. The maximum specific heat increment of 7.96% in solid phase and 11.48% in liquid phase, were achieved at a CuO nanoparticle concentration of 0.5wt%. A forming of intermediate layers composing of needle-like structures between nanoparticles and the salt was observed. The mixing model considering such an intermediate layer can be used to explain the observed specific heat enhancement at low particle concentrations. Both latent heat and onset temperature were decreased with increasing concentrations of CuO nanoparticles, while the melting temperature range was increased. When considering both latent heat and sensible heat contributions, the maximum increment of TES was achieved as 4.71% at 0.5wt% CuO concentration in the temperature range from 160°C to 300°C.

CuO Nanoparticles Inhibited Root Growth from Brassica nigra Seedlings but Induced Root from Stem and Leaf Explants.

Interests associated with nanoparticles (NPs) are budding due to their toxicity to living species. The lethal effect of NPs depends on their nature, size, shape, and concentration. Present investigation reports that CuO NPs badly affected Brassica nigra seed germination and seedling growth parameters. However, variation in antioxidative activities and nonenzymatic oxidants is observed in plantlets. Culturing the leaf and stem explants on MS medium in presence of low concentration of CuO NPs (1-20mgl-1) produces white thin roots with thick root hairs. These roots also show an increase in DPPH radical scavenging activity (up to 80% at 10mgl-1), total antioxidant, and reducing power potential (maximum in presence of 10mgl-1 CuO NPs in the media). Nonenzymatic antioxidative molecules, phenolics and flavonoids, are observed elevated but NPs concentration dependent. We can conclude that CuO NPs can induce rooting from plant explants cultured on appropriate medium. These roots can be explored for the production of active chemical constituents.

Effects of CuO nanoparticles on Lemna minor.

BackgroundCopper dioxide nanoparticles (NPs), which is a kind of important and widely used metal oxide NP, eventually reaches a water body through wastewater and urban runoff. Ecotoxicological studies of this kind of NPs effects on hydrophyte are very limited at present. Lemna minor was exposed to media with different concentrations of CuO NPs, bulk CuO, and two times concentration of Cu2+ released from CuO NPs in culture media. The changes in plant growth, chlorophyll content, antioxidant defense enzyme activities [i.e., peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activities], and malondialdehyde (MDA) content were measured in the present study. The particle size of CuO NPs and the zeta potential of CuO NPs and bulk CuO in the culture media were also analyzed to complementally evaluate their toxicity on duckweed.ResultResults showed that CuO NPs inhibited the plant growth at lower concentration than bulk CuO. L. minor roots were easily broken in CuO NPs media under the experimental condition, and the inhibition occurred only partly because CuO NPs released Cu2+ in the culture media. The POD, SOD, and CAT activities of L. minor increased when the plants were exposed to CuO NPs, bulk CuO NPs and two times the concentration of Cu2+ released from CuO NPs in culture media, but the increase of these enzymes were the highest in CuO NPs media among the three kinds of materials. The MDA content was significantly increased compared with that of the control from 50 mg L−1 CuO NP concentration in culture media.ConclusionCuO NPs has more toxicity on L. minor compared with that of bulk CuO, and the inhibition occurred only partly because released Cu2+ in the culture media. The plant accumulated more reactive oxygen species in the CuO NP media than in the same concentration of bulk CuO. The plant cell encountered serious damage when the CuO NP concentration reached 50 mg L−1 in culture media. The toxicology of CuO NP on hydrophytes must be considered because that hydrophytes are the basic of aquatic ecosystem.

Interactive effects of copper oxide nanoparticles and light to green alga Chlamydomonas reinhardtii

The present study explores the effect of light with different spectral composition on the stability of CuO-nanoparticle (CuO-NP) dispersions and their effects to green alga Chlamydomonas reinhardtii. The results showed that simulated natural light (SNL) and light with enhanced UVB radiation (UVR*) do not affect the dissolution of CuO-NPs as compared to light irradiation conditions typically used in laboratory incubator (INC). Comparable values of ζ-potential and hydrodynamic size during 24h were found under all studied conditions. Concentrations of CuO-NPs below 1mgL−1 do not attenuate the light penetration in the algal suspensions in comparison with NP-free system. Exposure to a combination of 8μgL−1 or 0.8mgL−1 CuO-NPs and INC or SNL has no significant effect on the algal growth inhibition, algal fluorescence and membrane integrity under short-term exposure. However, an enhancement of the percentage of cells experiencing oxidative stress was observed upon exposure to 0.8mgL−1 CuO-NPs and SNL for 4 and 8h. Combination of UVR* and 0.8mgL−1 CuO-NPs resulted in synergistic effects for all biological endpoints. Despite the photocatalytic properties of CuO-NPs no significant increase in abiotic reactive oxygen species (ROS) production under simulated solar radiation was observed suggesting that the synergistic effect observed might be correlated to other factors than CuO-NP-mediated ROS photoproduction. Tests performed with CuSO4 confirmed the important role of dissolution as toxicity driving force for lower CuO-NP concentration. However, they failed to clarify the contribution of dissolved Cu on the combined effects at 0.8mgL−1 CuO-NPs. The results point out the necessity of taking into account the possible interactions between ENPs and changing light conditions when evaluating the potential effects of ENPs to phytoplankton in natural waters.

Performance enhancement of polymer solar cells using copper oxide nanoparticles

Copper oxide (CuO) is a p-type semiconductor with a band gap energy of 1.5 eV, this is close to the ideal energy gap of 1.4 eV required for solar cells to allow good solar spectral absorption. The inherent electrical characteristics of CuO nanoparticles make them attractive candidates for improving the performance of polymer solar cells when incorporated into the active polymer layer. The UV-visible absorption spectra and external quantum efficiency of P3HT/PC70BM solar cells containing different weight percentages of CuO nanoparticles showed a clear enhancement in the photo absorption of the active layer, this increased the power conversion efficiency of the solar cells by 24% in comparison to the reference cell. The short circuit current of the reference cell was found to be 5.234 mA cm−2 and it seemed to increase to 6.484 mA cm−2 in cells containing 0.6 mg of CuO NPs; in addition, the fill factor increased from 61.15% to 68.0%, showing an enhancement of 11.2%. These observations suggest that the optimum concentration of CuO nanoparticles was 0.6 mg in the active layer. These significant findings can be applied to design high-efficiency polymer solar cells containing inorganic nanoparticles.

Heat Transfer Enhancement using CuO / Water Nanofluid in a Shell and Helical Coil Heat Exchanger

Forced convective heat transfer studies have been carried out in an agitated shell and helical coil heat exchanger using CuO/water nanofluid. Experiments have been carried out in a shell and helical coil heat exchanger at various concentrations of CuO nanoparticles in water (0.3, 0.6, 1, 1.5 and 2% wt.), stirrer speeds (500, 1000 and 1500rpm) and shell-side fluid (heating medium) temperatures (40, 45 and 50oC). Water has been used as coil-side fluid, and studies have been conducted at different values of Dean number (flow rates). Enhancement in heat transfer due to the use of nanofluid has been reported in terms of heat transfer rate.

SELDI-TOF MS-based discovery of a biomarker in Cucumis sativus seeds exposed to CuO nanoparticles

Metal oxide nanoparticles (NPs) can inhibit plant seed germination and root elongation via the release of metal ions. In the present study, two acute phytotoxicity tests, seed germination and root elongation tests, were conducted on cucumber seeds (Cucumis sativus) treated with bulk copper oxide (CuO) and CuO NPs. Two concentrations of bulk CuO and CuO NPs, 200 and 600ppm, were used to test the inhibition rate of root germination; both concentrations of bulk CuO weakly inhibited seed germination, whereas CuO NPs significantly inhibited germination, showing a low germination rate of 23.3% at 600ppm. Root elongation tests demonstrated that CuO NPs were much stronger inhibitors than bulk CuO. SELDI-TOF MS analysis showed that 34 proteins were differentially expressed in cucumber seeds after exposure to CuO NPs, with the expression patterns of at least 9 proteins highly differing from those in seeds treated with bulk CuO and in control plants. Therefore, these 9 proteins were used to identify CuO NP-specific biomarkers in cucumber plants exposed to CuO NPs. A 5977-m/z protein was the most distinguishable biomarker for determining phytotoxicity by CuO NPs. Principal component analysis (PCA) of the SELDI-TOF MS results showed variability in the modes of inhibitory action on cucumber seeds and roots. To our knowledge, this is the first study to demonstrate that the phytotoxic effect of metal oxide NPs on plants is not caused by the same mode of action as other toxins.

Experimental Investigation of Vapor Compression Refrigeration System Performance Using Nano-Refrigerant

Experimental investigation of vapor compression refrigeration system performance using Nano-refrigerant is presented in this work. Nano-refrigerant was prepared in current work by mixing 50 nanometers diameter of copper oxide CuO nanoparticles with Polyolester lubrication oil and added to the compressor of the refrigeration system to be mixed with pure refrigerant R-134a during its circulation through refrigeration system. Three concentrations (0.1%, 0.25%, and 0.4%) of CuO-R134 a Nano-refrigerant are used to study the performance of the refrigeration system test rig and to investigate the effect of using Nano-refrigerant as a working fluid compared with pure refrigerant R-134a. The results showed that, the increasing in concentration of CuO nanoparticles in the Nano-refrigerant will significantly enhance the performance of the refrigeration system, as adding nanoparticles will increase the thermal conductivity, heat transfer and improve the thermo-physical properties of Nano-refrigerant. Investigation of performance parameters for refrigeration system using Nano-refrigerant with 0.4% concentration compared with that for pure refrigerant R-134a shows that, Nano-refrigerant has reflect higher performance in range of 10% and 1.5% increase in COP and refrigeration effect respectively and 7% reduction in power consumption for refrigeration system. It can be concluded that, Nano-refrigerants can be efficiently and economically feasible to be used in the vapor compression refrigeration systems.

Optimize the Evaporating Heat Transfer Coefficient of Refrigeration System Using Nano Fluid

Improving heat transfer characteristics in refrigeration and air conditioning systems has been intensively studied by many investigators. In the present work the effect of using CuO-R134a in the vapour compression system on the evaporating heat transfer coefficient is investigated by CFD heat transfer analysis using the FLUENT software. An experimental test rig is designed for this purpose. The test section is a horizontal tube in the tube heat exchanger made from copper. The refrigerant is evaporated inside an inner copper tube and the heat load is provided from hot water that passing in an annulus surrounding the inner tube. Heat transfer coefficients were evaluated using FLUENT for heat flux ranged from 10 to 40 kW/m2, using nanoCuO concentrations ranged from 0.05 to 1% and particle size from 15 to 70 nm. The measurements indicated that for a certain nanoconcentration as heat flux or mass flux increases the evaporating heat transfer coefficient increases and also that the evaporating heat transfer coefficient increases with increasing nanoCuO concentrations up to certain value then decreases. The obtained evaporating heat transfer coefficient result have been optimized at its maximum value for the best CuOnano particles concentration in R134a refrigerant.

Experimental investigation of the forced convective boiling heat transfer of R-600a/oil/nanoparticle

In this paper an experimental study of convective boiling heat transfer of R-600a/oil/nanoparticle mixtures is investigated. The experimental setup was prepared with a smooth horizontal tube as a test section with the length and diameter of 9.5 and 103mm, respectively, and pure R-600a was applied for evaluating the heat transfer enhancement. Six mixtures containing 1% weight fraction of R-600a/oil with different concentrations of CuO nanoparticles including 0.0, 0.5, 1.0, 1.5, 2.0 and 5.0% weight fraction of R-600a/oil/nanoparticle were used in our study.The mass velocity per cross area was considered at the range of 50–700kg/m2s for low vapor quality (ϕ<0.25). The results showed that the convective boiling heat transfer coefficient will be increased by increasing the mass fraction of nanoparticles up to 2%, while by increasing the mass fraction of nanoparticles up to 5% the heat transfer coefficient will be reduced.