CuO Nanoparticles Research Articles

Green Synthesis of CuO Nanoparticles Mediated Rhazya Stricta Plant Leaves Extract Characterization and Evaluation of their Antibacterial and Anticancer Activity (in vitro Study)

In this study, a straightforward, expeditious, and environmentally friendly approach to synthesize copper oxide nanoparticles (CuONPs) utilizing an aqueous extract of Rhazya Stricta (R. stricta) leaves was employed. The CuONPs underwent various analytical techniques for characterization, including X-ray diffractometer (XRD), field emission scan electron microscope (FESEM), energy dispersive X-ray (EDX) analyses, UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and zeta potential. The XRD analysis authenticated the monoclinic crystal nature, revealing an average crystallite size of 15.6 nm. FESEM images depicted semi-spherical and cubic shapes, with particle sizes ranging from 56.64 to 86.95 nm. The formation of CuONPs was initially confirmed by the observable change in colour, attributed to the excitation of surface Plasmon resonance at 280 nm in the UV-Vis spectra. FTIR analysis affirmed the presence of functional groups in the R. Stricta leaves extract, serving as both reducing and stabilizing agents, facilitating the formation of CuONPs. Zeta potential measurements indicated substantial stability with a value of 46.6 mV. The biosynthesized CuONPs were further evaluated for their antibacterial properties against Klebsiella Pneumoniae (K. pneumoniae) and Staphylococcus aureus (S. aureus), yielding inhibition zones of 21 mm and 30 mm, respectively. Additionally, the cytotoxicity assessment of CuONPs against A549 cell lines revealed higher cytotoxicity of 81.47 ± 1.517 at a CuONP concentration of 100 μg/ml. This work is the first attempt at R. stricta-facilitated synthesis of CuONPs as antibacterial and anticancer agents. It can subsequently be exploited as a potential candidate for these agents and might be utilized further in vivo studies.

Numerical investigation of performance enhancement in a PCM-based thermal energy storage system using stair-shaped fins and nanoparticles

This study numerically investigates the melting performance enhancement of phase change material (PCM) in a latent heat thermal energy storage (LHTES) unit using a novel stair-shaped fin and nano-enhanced PCM. Different fin configurations are designed and their thermal performance is compared to traditional straight fins, while the total mass of fins is kept constant. Nano-enhanced PCM is prepared by the inclusion of CuO nanoparticles into RT82 as PCM. The simulation results reveal that the stair-shaped fins can notably enhance the efficiency of phase change compared to the traditional straight fins. The configuration with more extended fin close to the lower zone of the latent heat thermal energy storage unit had the best thermal performance. The full PCM melting time for the most efficient stair-shaped fin configuration is reduced by 52% compared to the straight fins. The combined impacts of the most effective stair-shaped fin design and nanoparticles on the phase change melting performance are evaluated. The inclusion of nanoparticles with volume concentrations of 2% and 5% into the pure PCM leads to 61% and 65% reduction in charge rate, respectively, as compared to the straight fin with pure PCM.

Efficient electroreduction of CO2 to acetate with relative purity of 100% by ultrasmall Cu2O nanoparticle on a conductive metal-organic framework

Efficient electroreduction of CO2 to acetate with relative purity of 100% by ultrasmall Cu2O nanoparticle on a conductive metal-organic framework

Synthesis and application of an effective magnetic catalyst immobilized copper oxide for the one-pot ultrasound-assisted synthesis of 1,4-dihydropyridines

In this study, Fe3O4 was modified with a biocompatible carbohydrate D-(+)-ribonic γ-lactone (RL) followed by immobilization with CuO nanoparticles (CuO NPs) to produce Fe3O4-APTES-RL-CuO as a Lewis acid catalyst. The sustainable RL can be utilized as a novel support for CuO NPs with increased catalytic activity. RL with plenty of hydroxyl groups not only catch the CuO NPs and prevents them from agglomeration but also, prevails upon immobilization of CuO NPs making the nanohybrid RL-supported CuO NPs significantly stable. This green and effective heterogeneous catalyst can be used for one-pot ultrasound-assisted synthesis of 1,4-dihydropyridines (1,4-DHPs) with high yield (95٪) and short time (15 min). The catalyst can be separated easily and cleanly by using an external magnet. This nanomagnetic catalyst is reused five times without any remarkable reduction in its activity. To illustrate the structure of the catalyst and characterize its physicochemical properties, different techniques like FT-IR, XRD, FE-SEM, EDS, TGA, and VSM were applied.

Scavenger-free solar photocatalytic degradation of Textile Dyes and Antibiotics using magnetically separable bi-junctional photocatalyst

The field of solar photocatalysis has been plagued by photocatalysts with low photon-to-electron conversion efficiency, resulting in poor photocatalytic degradation rates of water pollutants. With a keen idea to improve the existing photocatalysts, we developed a scavenger-free, magnetically separable, bi-junctional solar photocatalyst. The photocatalyst comprises Fe2+ doped zinc ferrite as core, ZnO as shell, and irregular CuO nanoparticles in conjunction with the surface of core-shell nanoparticles prepared using a combination of microwave-assisted solvothermal technique and microwave-assisted reflux method. The photocatalytic degradation properties of the solar photocatalyst were modelled and optimized with the help of Methyl Orange under direct sunlight. This novel composite degrades Methyl Orange roughly four times faster than core-shell nanoparticles. The photocatalyst meets most of the criteria for working of a promising solar photocatalyst, such as 1) excellent absorption of sunlight, 2) two physically distinct heterojunction and absorbing regions for efficient charge carrier generation and separation, 3) scavenger-free degradation of textile dyes and antibiotics, 4) High surface area (39 m2g −1), 5) good stability, 6) excellent reusability, 7) and easy separation of nanoparticles for reuse with the help of a magnet. The prepared photocatalyst efficiently degrades fluoroquinolone antibiotics such as Ciprofloxacin Hydrochloride, Norfloxacin, and Ofloxacin. The photocatalyst demonstrates the capability to efficiently degrade textile dyes such as Methyl Orange, Methylene Blue, Orange G, Fluorescein sodium salt, Rhodamine B, and Crystal Violet. Additionally, the bi-junctional photocatalyst can be coated with a thin layer of silver to achieve twice the degradation rate. This enhancement is attributed to the Localized Surface Plasmon Resonance (LSPR) effect. The current work presents an effective and economical option for removing dyes and antibiotics in wastewater, marking a significant stride towards sustainable industrial practices.

Oxidation cocatalyst/S-scheme junction cooperatively assists photocatalytic H2 production in ternary hybrid: The case of PdO@TiO2-Cu2O

Solar-driven photocatalytic hydrogen production from water splitting holds significant potential in addressing the energy crisis and environmental pollution. However, rapid recombination of photogenerated carriers and insufficient surface catalytic reaction kinetics hinder the photocatalytic process. Constructing the catalytic systems with multi-channel charge-separation can effectively alleviate those issues. In this work, ternary PdO@TiO2-Cu2O composites have been synthesized through precursor calcination and low-temperature reduction, where PdO and Cu2O nanoparticles couple with the TiO2 nanorods. Comparing to single TiO2, binary PdO@TiO2 and TiO2-Cu2O, the PdO@TiO2-Cu2O hybrid exhibits enhanced photocatalytic hydrogen production performance (5831μmol g-1h−1), with a hydrogen production rate more than three times that of single TiO2. Based on the band structures of TiO2 and Cu2O, along with the photochemical/electrochemical, in-situ EPR, Photoluminescence (PL) tests, and work function calculations, the formation of an S-scheme heterojunction at the TiO2-Cu2O interface under light illumination facilitates the recombination of electrons in the conduction band (CB) of TiO2 with holes in the valence band (VB) of Cu2O. In this regard, the established built-in electric field significantly accelerates the transfer of photogenerated charges while preserving their respective strong oxidation and reduction capabilities. Meanwhile, the introduction of PdO enriches the holes and further enhances the rate of charge separation. This S-scheme heterojunction with directional charge transfer and oxidation cocatalyst collectively form multi-channels of charge separation, optimizing charge migration and enabling efficient hydrogen production, thus improving the photocatalytic capability of pristine TiO2. This study provides a rational approach to construct efficient S-scheme heterojunction/oxidation cocatalyst multi-component catalytic systems for water splitting into hydrogen.

Investigation of antibacterial potential of CuO nanoparticles synthesised using Costus pictus leaf extract

The current research explores the production of CuO nanoparticles (NPs) using leaf extract from Costus pictus, employing environmentally friendly synthesis techniques. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the CuO NPs, with a crystallite size of 18.07 nm. UV–visible studies revealed an absorption peak at 297 nm. Using Fourier-transform infrared (FTIR) spectroscopy, absorption peaks within the wavelength range of 450–4000 cm−1 were identified to unveil the chemical composition of the NPs. Moreover, field emission scanning electron microscopy (FESEM) imaging displayed uniform and well-defined spherical morphology of the NPs, while TEM confirmed their size range to be 15–25 nm. Energy-dispersive spectroscopy (EDS) affirmed copper and oxygen presence, with homogeneous distribution confirmed by elemental maps. Zeta potential analysis revealed a value of −25.1 mV, indicating good stability due to the negative surface charge preventing aggregation. Dynamic Light Scattering (DLS) analysis showed an average particle size of 354.4 nm and a PDI of 0.379, indicating moderately uniform particles. Furthermore, the agar well diffusion method unveiled significant antibacterial activity against multiple strains, including S. aureus, S. mutans, P. aeruginosa, S. mutans and E. coli. Notably, CuO nanoparticles exhibited a substantial inhibition zone of 17.57 ± 0.58 mm against S. mutans, surpassing the 15 mm inhibition zone observed with ciprofloxacin. This study highlights CuO nanoparticle synthesis from Costus pictus leaves, revealing properties and potent antibacterial effects, opening avenues for catalysis, sensing, and biomedicine.

In-situ formed Li2O and an artificial protective layer on copper current collectors to enhance the cycling stability of lithium metal anode batteries

In this study, we present a facile one-step method for the thermal treatment of commercial Cu foils, leading to the growth of Cu2O and CuO nanoparticles in an air atmosphere, resulting in the coating of an artificial protective layer on the copper foil surface. The as-prepared CuO/Cu2O nanoparticles exhibit a spherical morphology, providing ample active sites to improve uniform lithium plating and cyclic stability by building a highly stable In-situ Li2O-rich solid-electrolyte interphase (ISEI). The artificial solid-electrolyte interphase (ASEI) protective layer contains graphene oxide (GO) as a filler with PVDF-HFP and lithium Nafion polymers, enhances Li+ ion migration, which reduces volume expansion and stabilizes the interface, preventing unwanted side reactions between active lithium and electrolytes by facilitating controlled lithium deposition underneath. For integration into an anode-less full cell based on a 2032-type coin cell, alongside a lithium iron phosphate (LFP) cathode, the ISEI oxide layer was grown on a Cu foil electrode (denoted as Cu-30) via a thermal treatment at 320 °C in air for 30 min and coated ASEI (denoted as GO@Cu-30). This cell demonstrated remarkable electrochemical performance. After 250 cycles at 0.5C, it exhibited an outstanding capacity retention of 93.12 % with 99.92 % CE, significantly surpassing the performance of a bare Cu foil, which showed a capacity retention of only 9.54 % with CE of 98.77 %. This work highlights the potential of a simple thermally treated Cu foil as a current collector to overcome the Anode-less lithium metal battery (ALMB) challenges associated with high-energy-density demand.

Development of a cellulose nanofiber composite film containing CuO/ZnO nanoparticles and its human norovirus inactivation properties in clams

Human norovirus (HuNoV) threatens human health worldwide, highlighting the critical need for antiviral materials. In this study, copper and zinc nanoparticles (NPs) as inorganic antiviral materials and a cellulose nanofiber (CNF) were selected to construct a hybrid inorganic-organic composite film (CuO/ZnO NPs-CNF) against MS2 and murine norovirus 1 (MNV-1) (surrogates for HuNoV) viruses. Selected NPs concentrations (50 µM of CuO NPs and 5 mM of ZnO NPs) showed non-toxicity (89.88 % of cell viability) through the MTT assay. Upon the development and characterization of the CuO/ZnO NPs-CNF film, high compatibility between CuO/ZnO NPs and CNF was identified, along with consistent thickness, low moisture content, and water solubility. A synergistic antiviral effect was exhibited in vitro and on the film against MS2 and MNV-1 in the mentioned co-treated inorganic matrix within 1 h. The antiviral stability of the film was also maintained at various temperatures (−18 °C, 5 °C, and 25 °C) and humidities (20–30 %, 50–60 %, and 70–80 %). When a synergistic antiviral effect was exhibited on the CuO/ZnO NPs-CNF film against both MS2 and MNV-1, mechanisms analysis by SDS-PAGE and RT-qPCR revealed that there were damages to both capsid protein and RdRP. The application of CuO/ZnO NPs-CNF film on clams resulted in a significant decrease in the survival rate of MS2 by up to 65.67 % and MNV-1 by up to 78.62 % when treated at low temperatures compared to the CNF film. Taken together, these results suggest that the CuO/ZnO NPs-CNF film could be used as potential anti-HuNoV agent in the food industry.

Enhanced photocatalytic performance of CuO nanoparticles synthesized via surfactant assisted hydrothermal method

Enhanced photocatalytic performance of CuO nanoparticles synthesized via surfactant assisted hydrothermal method

Cu(II) Biosorption and Synthesis of CuO Nanoparticles by Staphylococcus epidermidis CECT 4183: Evaluation of the Biocidal Effect

Copper contamination of natural waters is a global problem that affects ecosystems and public health, yet this metal is an essential micronutrient and has important applications. The efficacy of Staphylococcus epidermidis CECT 4183 as a Cu(II) biosorbent in synthetic solutions and its potential ability to synthesize CuO nanoparticles (CuO-NPs) from its cellular extract was investigated. In addition, the biocidal potential of the nanoparticles was evaluated against five microorganisms. Using response surface methodology, the optimal operating conditions were determined to be biomass dose, 0.2 g/L, and pH 5.5. Equilibrium tests were performed, and biosorption isotherms were obtained for four models with a maximum biosorption capacity of 48.14 mg/g for the Langmuir model. Different spectroscopic and microscopic techniques were used to determine the mechanisms involved in the biosorption process, which was dominated by surface physicochemical interactions with strong involvement of methyl, methylene, carbonyl, amino, and phosphate groups. The techniques also allowed for characterizing the obtained nanoparticles, which had a quasi-spherical morphology and an average size of 14 nm. Finally, biocidal tests showed that the CuO-NPs had a good inhibitory capacity for the microorganisms tested, with minimum inhibitory concentrations (MIC) between 62.5 and 500 µg/mL for bacteria and between 1000 and 2000 µg/mL for yeasts. S. epidermidis CECT 4183 showed good potential for Cu(II) bioremediation and for the synthesis of CuO-NPs with biocidal capacity. S. epidermidis CECT 4183 showed good potential for use in Cu(II) biosorption, and its cell extract presented a high capacity for the green synthesis of CuO-NPs, which at the same time turned out to be good biocidal agents.

Effect the Nanoparticles of Fe2O3 and CuO to Increasing the Activity of Sulfadiazine Against Multidrug Resistant Pseudomonas Aeruginosa

General Background: Antibiotic resistance is a critical global health issue, and innovative approaches are needed to combat multidrug-resistant (MDR) bacteria. Specific Background: Nanotechnology has emerged as a promising strategy to enhance antibiotic efficacy and reduce resistance. Knowledge Gap: However, there is limited understanding of how metal oxide nanoparticles (NPs) like Fe2O3 and CuO can be utilized to improve the performance of antibiotics such as sulfadiazine. Aims: This study aimed to synthesize Fe2O3 and CuO nanoparticles, conjugate them with sulfadiazine, and evaluate their antibacterial efficacy against MDR Pseudomonas aeruginosa. Results: The nanoparticles were synthesized via chemical precipitation, with Fe2O3 and CuO having mean crystal sizes of 41.40 nm and 44.83 nm, respectively. When bound to sulfadiazine, the crystal sizes were 42.62 nm (Fe2O3) and 38.77 nm (CuO). The minimum inhibitory concentration (MIC) values for sulfadiazine-bound CuO and Fe2O3 NPs ranged from 16-32 μg/ml, significantly lower than the 64-128 μg/ml observed for standard sulfadiazine. Hemolysis assays confirmed the biocompatibility of these nanocomposites at tested concentrations. Novelty: The study reveals that Fe2O3 and CuO nanoparticles significantly enhance sulfadiazine's antibacterial activity against MDR P. aeruginosa, suggesting a potential method to bypass traditional resistance mechanisms. Implications: The study suggests that nanoparticle-conjugated antibiotics could be a promising solution for combating antibiotic resistance, potentially reducing its negative impact on public health. Highlights: Nanoparticles reduce sulfadiazine's MIC against MDR Pseudomonas aeruginosa. Fe2O3 and CuO nanoparticles enhance antibiotic efficacy. Hemolysis assays confirm nanocomposites' safety and biocompatibility. Keywords: Nanotechnology, Antibiotic Resistance, Fe2O3 Nanoparticles, CuO Nanoparticles, MDR Pseudomonas aeruginosa

Cu2O Nanoparticles as Nanocarriers and Its Antibacterial Efficacy.

In this study, Cu2O nanoparticles were synthesized using the sol-gel technique and subsequently functionalized with extracts from plants of the Rauvolfioideae subfamily and citrus fruits. Comprehensive characterization techniques, including UV-Vis spectroscopy, FT-IR, XRD, BET, SEM, and TEM, were employed to evaluate the structural and surface properties of the synthesized nanoparticles. The results demonstrated that both functionalized Cu2O nanoparticles exhibit mesoporous structures, as confirmed by nitrogen adsorption-desorption isotherms and the pore size distribution analysis. The green extract functionalized nanoparticles displayed a more uniform pore size distribution compared to those functionalized with the orange extract. The study underscores the potential of these functionalized Cu2O nanoparticles for applications in drug delivery, catalysis, and adsorption processes, highlighting the influence of the functionalization method on their textural properties and performance in antibacterial efficacy.

Asian Spice Nanotech: Illicium verum made Metal Nanoparticles for Potent Antibacterial and Catalytic Applications

Introduction: Asian spices are globally recognized for their rich phytochemical composition. The bioactive compounds of Asian spices have significant potential to extend the biological applications of metal nanomaterials by increasing their surface area, stability, dispersion, and ecofriendliness. Method: The present study is designed to prepare novel iron oxide (Fe2O3) and copper oxide (CuO) nanoparticles using an aqueous extract of Illicium verum (star anise), a traditional Asian spice as a reducing, capping & stabilizing agent. The synthesized nanoparticles have been characterized to study their molecular environment using Fourier-transform infrared spectroscopy (FTIR). Elemental composition was examined through the Energy dispersive X-ray Spectroscopy (EDS). Scanning Electron Microscopy (SEM) revealed the size, shape, and other morphological characteristics of nanoparticles. The optical properties have been tested through Ultraviolet-Visible (UV) spectroscopy and the band gap energies of both Fe2O3 and CuO nanoparticles have been calculated by using the Tauc plot method, which explores its semiconductor applications. The catalytic applications of obtained nanoparticles have shown significant potential in the degradation of aqueous methyl orange dye (MO). Results: Results revealed that Fe2O3 and CuO nanoparticles significantly increased the rate of reaction by decreasing the reaction time to 45 mins and 40 mins, respectively in comparison to the NaBH4 (60 mins). This shows that CuO has a larger surface area and more absorption capacity than Fe2O3 NPs. To examine the cause of value healthcare, the obtained materials have also been applied against various Gram-positive and Gram-negative bacteria. The bactericidal activity was compared with gentamicin, which showed both nanometals are moderate to strongly active against tested microbes. Conclusion: The successful eco-friendly synthesis of metallic nanoparticles by using Asian spices and their applications in physical and biological sciences opens the door for the scientific community to develop and apply more novel and green nanomaterials in industrial and commercial areas.

Injectable Hydrogel-Encapsulating Pickering Emulsion for Overcoming Lenvatinib-Resistant Hepatocellular Carcinoma via Cuproptosis Induction and Stemness Inhibition.

Lenvatinib resistance (LenR) presents a significant challenge in hepatocellular carcinoma (HCC) treatment, leading to high cancer-related mortality rates globally. Unlike traditional chemotherapy resistance mechanisms, LenR in HCC is primarily driven by increased cancer cell stemness. Disulfiram, (DSF), functioning as a Cu ionophore, can coordinate with Cu2+ to overcome LenR in HCC by inhibiting cancer cell stemness and cuproptosis. However, DSF faces challenges due to its poor water solubility, while copper ions present issues related to systemic toxicity during widespread use. To address this, DSF and CuO nanoparticles (NPs) were co-encapsulated to form an oil-in-water Pickering emulsion (DSF@CuO), effectively elevating DSF and copper ion concentrations within the tumor microenvironment (TME). DSF@CuO was then combined with sodium alginate (SA) to form a DSF@CuO-SA solution, which gelatinizes in situ with Ca2+ in the TME to form a DSF@CuO Gel, enhancing Pickering emulsion stability and sustaining DSF and copper ion release. A DSF@CuO Gel exhibits enhanced stability and therapeutic efficacy compared to conventional administration methods. It effectively induces mitochondrial dysfunction and cuproptosis in LenR HCC cells by downregulating DLAT, LIAS, and CDKN2A, while upregulating FDX1. Furthermore, it suppresses cancer stemness pathways through activation of the JNK/p38 MAPK pathway and inhibition of the NF-κB and NOTCH signaling pathways. These findings suggest that DSF@CuO Gels are a promising therapeutic strategy for treating LenR HCC. In vivo and in vitro LenR HCC models demonstrated significant therapeutic efficacy. In conclusion, this novel approach underscores DSF@CuO Gel's potential to overcome LenR in HCC, offering a novel approach to address this clinical challenge.

Experimental research of convective heat transfer between nanofluids and high-temperature dense granite in deep geothermal reservoirs

Global warming is increasing as CO2 emissions from the use of conventional fossil fuels continue to rise. The development of geothermal energy is gradually becoming the key to the sustainable development of human society in the future. Enhancing the heat transfer performance of circulating heat transfer fluids is one of the effective means to efficiently exploit deep geothermal resources. In this study, a self-developed circulating heat exchange experimental setup was established. The convection heat transfer characteristics of nanofluids in high-temperature rocks were experimentally investigated. Al2O3 nanofluid and CuO nanofluid were used as the working medium for heat transfer in high temperature granite samples. The effects of the Reynolds number (1000–6000) and parameters such as nanoparticle type (CuO & Al2O3), size (20 nm & 40 nm) and mass fraction (0 wt%-2wt%) on the heat transfer intensity were analyzed. The effect of nanoparticle accumulation on the rock surface on the local heat transfer strength was also investigated. The results indicate that the increase of Reynolds number enhances the heat transfer strength of nanofluids in rocks. Nanofluid containing 20 nm Al2O3 nanoparticles has better heat transfer performance in rock than nanofluid containing 20 nm CuO nanoparticles. Meanwhile, the heat transfer performance of nanofluid containing 20 nm Al2O3 nanoparticles in rock is better than that of nanofluid containing 40 nm Al2O3 nanoparticles. The heat transfer intensity increases and then decreases as the nanoparticle mass fraction increases. The heat transfer coefficient at Reynolds number 6000 is 52.2 % higher than that of water. For nanofluids and water, the local heat transfer intensity decreases with increasing distance from the inlet. Meanwhile, accumulation of nanoparticles on rock surfaces during convective heat transfer enhances heat transfer intensity. The results show that nanofluids have the potential to be applied to deep geothermal resource extraction. This paper provides data and technical support for the application of nanomaterials in medium and deep geothermal systems to enhance heat transfer efficiency.

Enhancing the heat transfer in CuO-MWCNT oil hybrid nanofluid flow in a pipe

In this study, three-dimensional steady-state laminar flow simulations were conducted in a horizontal pipe using CuO and multi-walled carbon nanotubes (MWCNT) nanoparticles with engine oil as the base fluid. Various nanoparticle volume fractions were examined under a constant heat flux boundary condition applied to the pipe wall. The main goal was to assess and compare the effects of different nanoparticle volume concentrations, including CuO and MWCNT in ratios of 1:1 and 1:2, on convective heat transfer. A second-order discretisation method was employed for solving the equations, and the SIMPLE algorithm was used for pressure–velocity coupling in the CFD code. The study focused on the impact of nanoparticle volume fraction on the convective heat transfer coefficient and the Nusselt number at a Reynolds number of 750. The findings indicate that increasing the nanoparticle volume fraction enhances both the convective heat transfer coefficient and the Nusselt number, with MWCNT having a more pronounced effect compared to CuO. Specifically, adding 2% CuO increases the heat transfer coefficient by 65%, while a mixture of 1% CuO and 1% MWCNT boosts it by 75%. The thermal boundary layer thickness also grows with higher nanoparticle concentrations, with 1% CuO and 3% CuO increasing the thickness by 1.5% and 3.6%, respectively. A formula for the thermal boundary layer thickness in CuO-oil nanofluids is provided based on volume fraction, and a scale analysis of the average heat transfer coefficient confirms that the simulation results are consistent with this analysis.

CuO Nanoparticles Reduce Toxicity and Enhance Bioaccumulation of Cadmium and Lead in the Cells of the Microalgae Desmodesmus communis.

The removal of pollutants, including heavy metals, from the aquatic environment is an urgent problem worldwide. Actively developing nanotechnology areas is becoming increasingly important for solving problems in the field of the remediation of aquatic ecosystems. In particular, methods for removing pollutants using nanoparticles (NPs) are proposed, which raises the question of the effect of a combination of NPs and heavy metals on living organisms. In this work, we investigated the role of CuO-NPs in changing the toxicity of Cd and Pb salts, as well as the bioaccumulation of these elements in a culture of the microalga Desmodesmus communis. It was found that CuO-NPs at concentrations of 10, 100, and 1000 µg L-1 had no effect on the viability of microalgae cells. On the 14th day of the experiment, Cd at a concentration of 1 mg L-1 reduced the viability index by 30% and, when combined with CuO-NPs, by 25%, i.e., CuO-NPs slightly reduced the toxic effect of Cd. At the same time, in this experiment, when CuO-NPs and Cd were used together, the level of oxidative stress increased, including on the first day in mixtures with 1 mg L-1 Cd. Under the influence of Pb, the cell viability index decreased by 70% by the end of the experiment, regardless of the metal concentration. The presence of CuO-NPs slightly reduced the toxicity of Pb in terms of viability and reactive oxygen species (ROS). At the same time, unlike Cd, Pb without NPs caused ROS production on the first day, whereas the addition of CuO-NPs completely detoxified Pb at the beginning and had a dose-dependent effect on mixtures at the end of the experiment. Also, the introduction of CuO-NPs slightly reduced the negative effect of Pb on pigment synthesis. As a molecular mechanism of the observed effects, we prioritized the provocation of oxidative stress by nanoparticles and related gene expression and biochemical reactions of algae cells. Analysis of the effect of CuO-NPs on the Cd and Pb content in microalgae cells showed increased accumulation of heavy metals. Thus, when algae were cultured in an environment with Cd and CuO-NPs, the Cd content per cell increased 4.2 times compared to the variant where cells were cultured only with Cd. In the case of Pb, the increase in its content per one cell increased 6.2 times when microalgae were cultured in an environment containing CuO-NPs. Thus, we found that CuO-NPs reduce the toxic effects of Cd and Pb, as well as significantly enhance the bioaccumulation of these toxic elements in the cells of D. communis microalgae. The results obtained can form the basis of technology for the nanobioremediation of aquatic ecosystems from heavy metals using microalgae.

Modification of clinoptilolite as a natural zeolite by copper oxide nanoparticles for efficient desulfurization of kerosene

In recent years, researchers are looking for ways to reduce the amount of sulfur in kerosene. Therefore, desulfurization of kerosene is considered an important commercial and environmental process. Among the hard and complicated methods available for the desulfurization process, natural zeolites can be a suitable alternative for the desulfurization of oil products due to their economic efficiency, biocompatibility, and natural abundance of oil reserves. In this research, natural zeolite (clinoptilolite) was modified with CuO nanoparticles and used as adsorbent for desulfurization of kerosene. The effect of important parameters such as adsorbent dose, pH of solution and initial adsorbate concentration were investigated. Results indicated the optimum conditions as follows: dose of adsorbent 2 g, pH 10 and the adsorbate dose 200 ppm. Results showed that the modified adsorbent is a suitable, low-cost and good efficiency for the desulfurization process of kerosene.

Lettuce (Lactuca sativa L.) alters its metabolite accumulation to cope with CuO nanoparticles by promoting antioxidant production and carbon metabolism.

Copper-based nanoparticles (NPs) are gradually being introduced as sustainable agricultural nanopesticides. However, the effects of NPs on plants requires carefully evaluation to ensure their safe utilization. In this study, leaves of 2-week-old lettuce (Lactuca sativa L.) were exposed to copper oxide nanoparticles (CuO-NPs, 0 [CK], 100 [T1], and 1000 [T2] mg/L) for 15days. A significant Cu accumulation (up to 1966mg/kg) was detected in lettuce leaves. The metabolomics revealed a total of 474 metabolites in lettuce leaves, and clear differences were observed in the metabolite profiles of control and CuO-NPs treated leaves. Generally, phenolic acids and alkaloids, which are important antioxidants, were significantly increased (1.26-4.53 folds) under foliar exposure to NPs; meanwhile, all the significantly affected flavonoids were down-regulated after CuO-NP exposure, indicating these flavonoids were consumed under oxidative stress. Succinic and citric acids, which are key components of the tricarboxylic acid cycle, were especially increased under T2, suggesting the energy and carbohydrate metabolisms were enhanced under high-concentration CuO-NP treatment. There was also both up- and down-regulation of fatty acids, suggesting cell membrane fluidity and function responded to CuO-NPs. Galactinol, which is related to galactose metabolism, and xanthosine, which is crucial in purine and caffeine metabolism, were down-regulated under T2, indicating decreased stress resistance and disturbed nucleotide metabolism under the high CuO-NP dose. Moreover, the differentially accumulated metabolites were significantly associated with plant growth and its antioxidant ability. Future work should focus on controlling the overuse or excessive release of NPs into agricultural ecosystems to limit their adverse effects.