Zinc Oxide Nanoparticles Nanoparticles Research Articles

Sonochemical synthesis of bioinspired graphene oxide–zinc oxide hydrogel for antibacterial painting on biodegradable polylactide film

Graphene oxide nanosheet (GO) is a multifunctional platform for binding with nanoparticles and stacking with two dimensional substrates. In this study, GO nanosheets were sonochemically decorated with zinc oxide nanoparticles (ZnO) and self-assembled into a hydrogel of GO–ZnO nanocomposite. The GO–ZnO hydrogel structure is a bioinspired approach for preserving graphene-based nanosheets from van der Waals stacking. X-ray diffraction analysis (XRD) showed that the sonochemical synthesis led to the formation of ZnO crystals on GO platforms. High water content (97.2%) of GO–ZnO hydrogel provided good property of ultrasonic dispersibility in water. Ultraviolet-visible spectroscopic analysis (UV–vis) revealed that optical band gap energy of ZnO nanoparticles (∼3.2 eV) GO–ZnO nanosheets (∼2.83 eV). Agar well diffusion tests presented effective antibacterial activities of GO–ZnO hydrogel against gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus). Especially, GO–ZnO hydrogel was directly used for brush painting on biodegradable polylactide (PLA) thin films. Graphene-based nanosheets with large surface area are key to van der Waals stacking and adhesion of GO–ZnO coating to the PLA substrate. The GO–ZnO/PLA films were characterized using photography, light transmittance spectroscopy, coating stability, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopic mapping (EDS), antibacterial test and mechanical tensile measurement. Specifically, GO–ZnO coating on PLA substrate exhibited stability in aqueous food simulants for packaging application. GO–ZnO coating inhibited the infectious growth of E. coli biofilm. GO–ZnO/PLA films had strong tensile strength and elastic modulus. As a result, the investigation of antibacterial GO–ZnO hydrogel and GO–ZnO coating on PLA film is fundamental for sustainable development of packaging and biomedical applications.

Green Synthesis Derived Novel Fe2O3/ZnO Nanocomposite for Efficient Photocatalytic Degradation of Methyl Orange Dye

Introduction: An eco-friendly method was reported for the synthesis of ferric oxide nanoparticles (Fe2O3), zinc oxide nanoparticles (ZnO) and Fe2O3/ZnO nanocomposite using Mangifera indica plant leaf extract as a natural reducing agent. Methods: The synthesized nanomaterials were successfully characterized by X-ray diffraction, UVvisible spectrophotometer, Photoluminescence spectroscopy and Transmission electron microscopy. The obtained XRD spectrums revealed the crystalline nature of synthesized materials and the average diameters of Fe2O3 nanoparticles, ZnO nanoparticles and Fe2O3/ZnO nanocomposite came out to be 11.33 nm, 14.31 nm and 9.80 nm, respectively. The UV-visible absorbance spectra and photoluminescence spectrums confirmed that the Fe2O3/ZnO nanocomposite was visible light active and had excitation peaks in the visible range. Results: The TEM analysis confirmed the composite and semiconductor nature of the synthesized Fe2O3/ZnO nanocomposite. Furthermore, the photocatalytic activity of Fe2O3/ZnO nanocomposite reaches about 91.07% degradation of methyl orange dye within a time period of 150 min at an optimized catalyst dose. Adsorption isotherm and kinetic study were also applied to validate the study. Conclusion:: It was found that there was monolayer adsorption of methyl orange dye molecules on the surface of the synthesized catalyst under optimized experimental conditions and also, the adsorption process follows the pseudo-second-order kinetic model.

Numerical and Experimental Investigation of Nano zinc Oxide's Effect on the Mechanical Properties of Chloroprene and Natural Rubber (CR/NR) Composites

Nanocomposites, especially natural rubber (NR), have been extensively studied for their unique features and superior performance in tire applications. The present research investigated the impact of zinc oxide nanoparticles (ZnO) on the performance of typical rotary machine seals made of chloroprene rubber / natural rubber (CR/NR) composites. An ordinary standard rubber two-roll mill and hydraulic press were used to prepare high-temperature vulcanized CR/NR samples filled with ZnO nanoparticles. Tensile strength, tear resistance, abrasion resistance, resilience, and hardness were measured to determine the effects of nanoparticles on these physical and mechanical properties. Based on the various hyperelastic modeling schemes, enhancement in multiple characteristics of the control sample, such as overhaul properties, was observed. Furthermore, results show that increasing nanoparticle content in the vulcanisates increased the physicomechanical characteristics, such as hardness, resilience, tensile strength, and elastic Modulus at 200% strain. Moreover, hyperelastic analytical modeling shows that the differences with experimental results are less than 5%.

Seaweed biomass as a sustainable resource for synthesis of ZnO nanoparticles using Sargassum wightii ethanol extract and their environmental and biomedical applications through Gaussian mixture model

Zinc oxide nanoparticles (ZnO) possess unique features that mak them a common matter among different industries. Nevertheless, traditional models of synthesizing ZnO-NPs are related with health and environmental and risks due to harmful chemicals. The biosynthesis of zinc oxide nanoparticles was achieved using the hot water extract of Sargassum wightii (SW), which serves as a reducing agent. This extract is mixed with zinc precursors, initiating a bio-reduction process. UV–vis, FTIR, XRD, Raman, DLS, SEM, EDX, TEM imaging, and XPS analysis are used. The novelty of this research lies in utilizing a bio-reduction process involving hot water extract of SW to synthesize zinc oxide nanoparticles, providing a safer and eco-friendly alternative to traditional chemical methods. Here, the zinc oxide nanoparticles produced through the biosynthesis process effectively addressed oral infections (Streptococcus mutans) due to their ability to disrupt the integrity of bacterial cell membranes, interfere with cellular processes, and inhibit the growth and proliferation of bacteria responsible for oral infections. Gaussian Mixture Models (GMMs) uncover intricate patterns within medical data, enabling enhanced diagnostics, treatment personalization, and patient outcomes. This study aims to apply Gaussian Mixture Models (GMMs) to medical data for subpopulation identification and disease subtyping, contributing to personalized treatment strategies and improved patient care. With a dataset comprising 300 samples, the application of GMM showed lower BIC and AIC values (2500, 3200), a high Silhouette Score (0.65 from −1 to 1) reflecting well-defined clusters, Calinski-Harabasz (120) and Davies-Bouldin Indices (0.45). These metrics collectively underscored the model's success in revealing distinct patterns within the data. ZnO-nanocoated aligners were effective against Streptococcus mutans, with the maximum antibacterial effect observed for 2 days and lasting for 7 days.

Performance of bacterial nanocellulose packaging film functionalised in situ with zinc oxide: Migration onto chicken skin and antimicrobial activity

Zinc oxide nanoparticles (ZnO) are cost-effective antimicrobial agents with great potential for the active packaging industry. Bacterial NanoCellulose (BNC) features a porous fibre network, with high absorption capacity, flexible and with good mechanical properties, suitable as a carrier of active agents. In this work, BNCZnO films were developed and optimized regarding the particle size and ZnO concentration. The NaOH dropwise addition to BNC membranes immersed in Zn(CH3COO)2-PVOH enabled the production of ZnO nanoparticles with an z-average of 144 nm and a low polydispersity index. High ZnO incorporation (∼27%mZn/mBNCZnO) was obtained, with uniform distribution all over the BNC membranes. These composites were then characterized and evaluated for Zn migration using food simulants (10%, 20%, and 50% ethanol) with results lower than the limit. Migration into chicken skin, as a real food model, was low at 4 °C but exceeded the migration limit at 10 and 22 °C. Zn migration was also found to be temperature and pH dependent. When applied to chicken skin, BNCZnO was effective against E. coli, Salmonella (0.5–1.0 log reduction), and Campylobacter spp. (2.0 log reduction), indicating its potential for active packaging applications.

Channel length effect of P3HT:ZnO hybrid blend layer on electrical characteristics of thin-film transistors

In this present work, p-type bottom gate-bottom contact OTFTs based on semiconductor polymer poly(3-hexylthiophene) (P3HT) incorporating zinc oxide nanoparticles (ZnO) (OTFTs-P3HT:ZnO hybrid blend) with various channel lengths (L=2.5 µm, 5 µm, 10 µm and 20 µm) and constant channel width (W=10 mm) were elaborated using solution-processed P3HT:ZnO thin films, as an active layer, deposited on a Si/SiO2 substrate, without any surface treatment, by spin coating technique, and then were characterized. ZnO nanoparticles are utilized as acceptors and electron extraction materials. The effect of the channel length variation on the electrical parameters of these transistors at room atmosphere in saturation regime, has been investigated in order to better understand the dependency between the electrical performance and the channel length variation effect. As p-channel transistors, the fabricated devices exhibit a considerable variation in electrical parameters such as amount of hysteresis (△Vhyst), threshold voltage (Vth), density of trapped charges (Ntrap), sub-threshold slope (SS), density of the interface trap (Dit), field-effect saturation mobility (µsat) and current ratio (Ion/Ioff) with the increase of the channel length. In this study, we report a significant improvement in the efficiency of our devices in terms of good output characteristics and good electrical parameters such as low threshold voltage, low Ioff current, reduction of trap density and better field-effect saturation mobility when the channel length increases. These particularly promising results offer the possibility of using these organic thin-film transistors in several application domains such as low-cost sensing and non-volatile memory devices.

UYARLANABİLİR KONFOR ÖZELLİKLERİNE SAHİP PASİF GÜNDÜZ SOĞUTUCU PAMUKLU KUMAŞLAR

Passive daytime radiative cooling materials have attracted increasing attention due to their great potential for energy saving and the possibility to meet the need for smart clothes. However, the practical application of passive daytime cooling material in the textile industry is greatly affected by comfort components and also physical/mechanical properties that require optimization. Herein, it was aimed to develop a thermoregulating fabric using zinc oxide nanoparticles (ZnO), which provide dynamic and passive control of the infrared transmission, by adapting to the ambient temperature. For this aim, the cotton fabric was coated with a nanocomposite treatment composed of ZnO nanoparticles and temperature-responsive shape memory polyurethane (SMPU) matrix, obtaining strong scattering effects to control the wideband transmission of thermal radiation and also adaptive comfort features based on shape memory function. By reflecting sunlight of SMPU-ZnO nanocomposite coating, the cotton fabric can reach an average temperature drop of ∼ 2.2°C and 0.4°C compared to the raw ones under direct sunlight and also indoor at 40°C, respectively. Also, SMPU and SMPU-ZnO nanocomposite coated cotton fabric exhibited dynamic air and water vapour permeability hence adaptive comfort features. Owing to passive cooling and also adaptive comfort features besides the simple production process, this smart fabric is promising to be widely used in sports or protective clothing areas.

Plant-mediated biosynthesis of zinc oxide nanoparticles from Delonix Elata: A promising photocatalyst for crystal violet degradation

Zinc oxide nanoparticles (ZnO) were biosynthesized in this study utilizing Delonix Elata leaves extract, and their size, phase study, and morphology were investigated using various techniques. Moreover, the photocatalytic effects of ZnO nanoparticles on the degradation of Crystal violet (CV) were assessed, and its outstanding capability as photocatalysis under UV light was noticed throughout the investigation. This is a 100% environmentally friendly method that does not employ any harmful or hazardous solvents. The biosynthesized ZnO nanoparticles were characterized using FETEM, XRD, FTIR, UV–vis, XPS and Raman spectroscopy. Crystal violet (CV) dye degradation was utilized to examine the catalytic activity of the synthesized nanoparticles. The photocatalytic efficacy against the Crystal violet (CV) dye was followed by first-order reaction kinetics, with a maximal degradation efficiency of 86 %. As a result, the biosynthesized ZnO nanoparticles synthesized from Delonix Elata leaves extract to have the potential to be used in photocatalytic applications.

Cow dung extract mediated green synthesis of zinc oxide nanoparticles for agricultural applications

In the present study, zinc oxide nanoparticles (ZnO) were synthesized using cow dung extract to apply sustainable agriculture from rural resources. Studies on their antibacterial potential against E. coli DH 5 alpha indicated lower antimicrobial activities than the bulk Zn and commercial Zn nanoparticles. Compared with control and commercial ZnO nanoparticles, the maximum seed germination, root length, and shoot length were observed after the priming of synthesized ZnO NPs. This study suggests that ZnO may significantly increase seed germination and have lower antimicrobial potential. Further, the lower in-vitro cellular leakage and reactive oxygen species (ROS) production provided new hope for using cow dung extract mediated nanoparticles for agricultural and industrial applications.

Fabrication and characterization of polycaprolactone/chitosan nanofibers containing antibacterial agents of curcumin and ZnO nanoparticles for use as wound dressing.

The potential of the nanoscale structure is utilized by electrospun nanofibers, which are promising materials for wound dressings. Here, we prepared wound dressings constituting polycaprolactone (PCL) and chitosan (CS). Curcumin (Cur) and zinc oxide nanoparticles (ZnO) as antibacterial agents were embedded in PCL/CS electrospun nanofibers and different properties including morphology, physicomechanical, interaction with water, antibacterial efficiency, and in vitro studies were investigated. SEM images confirmed the nanofibrous structure of samples with 100 ± 5 to 212 ± 25 nm in average diameter. Elemental analysis of nanofibers showed a good distribution of ZnO along nanofibers which not only caused decreasing in nanofiber diameter but also increased tensile strength of nanofibers up to 2.9 ± 0.5 MPa and with good elongation at break of 39 ± 2.9. ZnO nanoparticles also facilitated the interaction of nanofibers with water, and this led to the highest water vapor transition rate, which was equal to 0.28 ± 0.02 g cm−2 day−1. The sample containing 3 wt% Cur had the highest water uptake value (367 ± 15%) and the lowest water contact angle (78 ± 3.7°), although Cur has a hydrophobic nature. The release profile of Cur showed a two-stage release and the Peppas model predicted a non-fickian diffusion. Simultaneous incorporation of CS, ZnO, and Cur effectively inhibited bacterial growth. In addition, in vitro studies represented that high content of Cur decreases cell viability and cell attachment. The outcomes from the fabricated nanofibrous scaffolds demonstrated appropriate properties for application as a wound dressing.

Synthesis ZnO heterostructured nanophotocatalyst simulated solar light irradiation for removal contaminate Carbamazepine in aqueous solution

In this study, zinc oxide nanoparticles (ZnO) were produced in aqueous media to photodegrade harmful carbamazepine compounds (CBZ) in aqueous solution under simulated solar-light using the sol-gel technique with zinc chloride and NaOH as precursors. X-ray diffraction (XRD), FTIR analysis, Field Emission Scanning Electron Microscopy (FE-SEM), and UV–vis diffuse reflectance spectra (UV-vis DRS) were used to analyze the ZnO NPs powder. According to the XRD results, ZnO nanoparticles showed a hexagonal symmetry shape with 13 nm particle size value. The absorption bands of ZnO nanoparticles were identified using FT-IR spectra peaking. The ZnO nanoparticles produced in this work are spherical, as seen in the SEM picture, with a band gap of about 3.6 eV. The prepared Zinc Oxide nanoheterostructured photocatalyst utilized excellent performance in reducing Carbamazepine compound with an efficiency of 90%. This study took into account pH solution, catalyst loading, kinetic studies, TOC removal, regeneration, and reusability. The synthesized ZnO successfully removed the Carbamazepine medicine at pH=4. With an R-square of 0.99855, the produced photocatalyst fits well into the pseudo second order model. The ZnO heterostructured nanophotocatalyst retained its outstanding performance after numerous cycles of usage. For these observations, the Zinc Oxide heterostructured photocatalyst for Carbamazepine reduction is a promising photocatalyst.

Sol-gel zinc oxide nanoparticles: advances in synthesis and applications

Zinc oxide nanoparticles (ZnO) exhibit numerous characteristics such as biocompatibility, UV protection, antibacterial activity, high thermal conductivity, binding energy, and high refractive index that make them ideal candidates to be applied in a variety of products like solar cells, rubber, cosmetics, as well as medical and pharmaceutical products. Different strategies for ZnO nanoparticles’ preparation have been applied: sol-gel method, co-precipitation method, etc. The sol-gel method is an economic and efficient chemical technique for nanoparticle (NPs) generation that has the ability to adjust the structural and optical features of the NPs. Nanostructures are generated from an aqueous solution including metallic precursors, chemicals for modifying pH using either a gel or a sol as a yield. Among the various approaches, the sol-gel technique was revealed to be one of the desirable techniques for the synthesis of ZnO nanoparticles. In this review, we explain some novel investigations about the synthesis of zinc oxide nanoparticles via sol-gel technique and applications of sol-gel zinc oxide nanoparticles. Furthermore, we study recent sol-gel ZnO nanoparticles, their significant characteristics, and their applications in biomedical applications, antimicrobial packaging, drug delivery, semiconductors, biosensors, catalysts, photoelectron devices, and textiles.

Green Synthesis of Nano Zinc Oxide/Nanohydroxyapatite Composites Using Date Palm Pits Extract and Eggshells: Adsorption and Photocatalytic Degradation of Methylene Blue.

In this study, zinc oxide nanoparticles (ZnO) and nanohydroxyapatite (NHAP) were prepared in the presence of date palm pits extract (DPPE) and eggshells, respectively. Another four nanocomposites were prepared from ZnO and NHAP in different ratios (ZP13, ZP14, ZP15, and ZP16). DPPE and all nanomaterials were characterized using GC-MS, zeta potentials, particle size distributions, XRD, TEM, EDX, FTIR, and pHPZC. The characterization techniques confirmed the good distribution of ZnO nanoparticles on the surface of NHAP in the prepared composites. Particles were found to be in the size range of 42.3–66.1 nm. The DPPE analysis confirmed the presence of various natural chemical compounds which act as capping agents for nanoparticles. All the prepared samples were applied in the adsorption and photocatalytic degradation of methylene blue under different conditions. ZP14 exhibited the maximum adsorption capacity (596.1 mg/g) at pH 8, with 1.8 g/L as the adsorbent dosage, after 24 h of shaking time, and the static adsorption kinetic process followed a PSO kinetic model. The photocatalytic activity of ZP14 reached 91% after 100 min of illumination at a lower MB concentration (20 mg/L), at pH 8, using 1.5 g/L as the photocatalyst dosage, at 25 °C. The photocatalytic degradation of MB obeyed the Langmuir–Hinshelwood first-order kinetic model, and the photocatalyst reusability exhibited a slight loss in activity (~4%) after five cycles of application.

Blending Ratio Effect of ZnPc/ZnO Hybrid Nanocomposite on Surface Morphology and Structural Properties

Recently, organic/inorganic hybrid nanocomposites being the future in electronic applications. In this paper, we have investigated hybrid nanocomposite zinc phthalocyanine (ZnPc)/zinc oxide nanoparticles (ZnO). ZnPc/ZnO hybrid nanocomposites were prepared with different ratios (wt/wt) (1/0), (0/1), (0.75/0.25), (0.5/0.5), (0.25/0.75), and, deposited on glass substrates by spin coating technique. X-Ray diffraction investigate the structural of ZnPc/ZnO thin films and studied the morphological properties using field emission scan electron microscopy, the surface of ZnPc/ZnO hybrid nanocomposites shows the presence of nanorod-like structures represented the organic material (ZnPc) and spherical nanoparticles for (ZnO), that is depending on the ratio of the blend. In ratio (0.5/0.5) we get the preferred homogeneous surface between like-nanorod and spherical shapes were show various properties from pure compounds which used to prepare the blend. The distribution of ZnO nanoparticles on ZnPc particles nanorods led to the disappearance feature of ZnO morphological characterize and ZnPc decorated was dominated on the hybrid nanocomposite structure.

Photocatalytic and Biological Activity of ZnO Nanoparticles Using Honey

The innovation and development of water purification methods have been at the center of extensive research for several decades. Many nanoparticles are frequently seen in industrial waste water. In this research, zinc oxide nanoparticles (ZnO) were synthesized following an autocombustion method with and without honey capping. Structural crystallinity and bonding structure were examined via X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy. Optical behavior was analyzed using ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL). Size estimation and surface morphology were studied using scanning electron microscopy (SEM), while energy-dispersive spectroscopy (EDS) was performed to analyze the sample purity and elemental composition. The photocatalytic degradation of methylene blue (MB) by ZnO was assessed as it is an efficient water treatment process with high potential. The biological activity of ZnO nanoparticles was also investigated in terms of antibacterial and antifungal activities against different bacterial and fungal species. Surprisingly, the as-synthesized ZnO nanoparticles were found to be substantially bioactive compared to conventional drugs. Honey-mediated nanoparticles displayed 86% dye degradation efficiency, and that of bare ZnO was 60%. Therefore, the involvement of honey in the synthesis of ZnO nanoparticles has great potential due to its dual applicability in both biological and environmental remediation processes.

EFFECT OF ZINC OXIDE NANOPARTICLES ON THE THERMAL, MECHANICAL AND WATER ABSORPTION PROPERTIES OF POLYLACTIC ACID/CHITOSAN COMPOSITES

The aim of this work is to improve the mechanical, thermal and water absorption properties of PLCHZ composites. The formation of the composites are mixing polylactic acid with zinc oxide nanoparticles (ZnO) and chitosan as filler. It produced through the precipitation method using a water bath under a temperature of 60 oC. Five prepared samples are pure PLA, PLCH, PLCHZa, PLCHZb and PLCHZc. The incorporating effect of fillers on the properties of samples is investigated in terms of mechanical, thermal and water absorbtion test. The result showed that mechanical and thermal properties increased with the addition of ZnO nanoparticles compared to pure PLA and PLCH. Nevertheless, those properties increased up to 2 wt% of ZnO nanoparticles loading but decreased when it content is increased up to 3 wt% and 4 wt%. PLCHZa with the smallest content of 2 wt% ZnO nanoparticles showed the highest value of 15 MPa in tensile strength and 330.6 oC in thermal resistant. In water absorbtion test, PLCHZc with 4 wt% ZnO has better absorb ability as well as the lowest percentage absorption rate of 0.02% to 0.03%. It can be conclude that ZnO nanoparticles play an important role in the main properties of polymer composites.

Biosynthesized visible light-activated zinc oxide nanoparticle as bactericidal agent for Xanthomonas oryzae

Background: Synthesis of metal nanoparticles is one of the developed research field because of its primary use in the evolution of new technical areas. Among a variety of nanoparticles, zinc oxide nanoparticles (ZnO) have advantages because of the extraordinary physical and chemical properties. Current effort implied the composition of ZnO nanoparticles with the use of fennel seeds extract and its activity against plant pathogen Xanthomonas oryzae that causes bacterial leaf blight disease in Rice plant. Methods and materials: Zinc oxide nanoparticles were synthesized by a green method using fennel seeds extract (reducing capping agent) and zinc nitrate (precursor). The nanoparticles were further characterized and their photodynamic activation was assessed by quantifying the reactive oxygen species (ROS) by using diphenylisobenzofuran dye. The nanoparticles were then directly applied to Xanthomonas oryzae to assess its antibacterial efficacy. Further, the nanoparticle was used to check the efflux pump inhibition of Xanthomonas oryzae. Results: ZnO obtained were distinguished via UV–Visible spectroscopic (360 nm peak), and Transmission electron microscopy reveals the size of NPs (33 nm) and spherical shape. The ZnO synthesized portrayed an MIC (minimum inhibitory concentration) of 40 ug/mL against Xanthomonas oryzae. Interestingly, this activity was achieved via the activation of ZnO in visible light thus making them photodynamic with a quantum yield of 0.18, and generating three types of reactive oxygen species (ROS) for instance, singlet oxygen (35.12%), OH ions (30.1%), and OH radicals (34.71%). Conclusion: It can be concluded that a “nanospray” of this nanoparticle can be a better alternative to the presently available bactericidal agents for bacterial leaf blight disease.

Low-cost zinc-oxide nanoparticles for solar-powered steam production: Superficial and volumetric approaches

Using renewable energy, especially solar energy, is an essential requisite for preventing global warming and climate change. Solar-powered steam generation is one of the recent solutions to the problem of environmental pollution and can be a promising way to generate clean energy. In this study, the superficial and volumetric approaches of the zinc oxide nanoparticles (ZnO) in solar vapor generation have been compared experimentally. For the volumetric approach, the nanofluid performance at different mass concentrations (0.001%, 0.002%, and 0.004%) on the solar vapor generation was examined. For the superficial approach, the evaporative performance of delignified mulberry wood coated by ZnO nanoparticles as an absorbent (ZnO-Wood) was investigated. Moreover, the effect of nanoparticle size on optical and evaporative properties was evaluated. Finally, the economic performance of the ZnO nanofluid was compared to the other nanofluids. The results indicated that the evaporative efficiency of the nanofluids containing ZnO(50 nm) nanoparticles at 3 suns (3 kW/m2) was approximately two times greater than that of water (18%). However, the evaporative efficiency of ZnO-Wood was 3.15 (56%) times greater than that of water. In addition, the results of the nanoparticle size effect showed that increasing the size of nanoparticles from 20 nm to 50 nm in the superficial and volumetric approaches increases the evaporative efficiency by roughly 10% and 3%, respectively. Finally, the cost analysis of nanofluid for solar vapor generation illustrated that ZnO nanoparticles are cost-effective compared to other nanoparticles presented in the literature.

Graphene Oxide-ZnO Nanocomposites for Removal of Aluminum and Copper Ions from Acid Mine Drainage Wastewater.

Adsorption technologies are a focus of interest for the removal of pollutants in water treatment systems. These removal methods offer several design, operation and efficiency advantages over other wastewater remediation technologies. Particularly, graphene oxide (GO) has attracted great attention due to its high surface area and its effectiveness in removing heavy metals. In this work, we study the functionalization of GO with zinc oxide nanoparticles (ZnO) to improve the removal capacity of aluminum (Al) and copper (Cu) in acidic waters. Experiments were performed at different pH conditions (with and without pH adjustment). In both cases, decorated GO (GO/ZnO) nanocomposites showed an improvement in the removal capacity compared with non-functionalized GO, even when the pH of zero charge (pHPZC) was higher for GO/ZnO (5.57) than for GO (3.98). In adsorption experiments without pH adjustment, the maximum removal capacities for Al and Cu were 29.1 mg/g and 45.5 mg/g, respectively. The maximum removal percentages of the studied cations (Al and Cu) were higher than 88%. Further, under more acidic conditions (pH 4), the maximum sorption capacities using GO/ZnO as adsorbent were 19.9 mg/g and 33.5 mg/g for Al and Cu, respectively. Moreover, the removal percentages reach 95.6% for Al and 92.9% for Cu. This shows that decoration with ZnO nanoparticles is a good option for improving the sorption capacity of GO for Cu removal and to a lesser extent for Al, even when the pH was not favorable in terms of electrostatic affinity for cations. These findings contribute to a better understanding of the potential and effectiveness of GO functionalization with ZnO nanoparticles to treat acidic waters contaminated with heavy metals and its applicability for wastewater remediation.

Microstructure Characterisation and Identification of the Mechanical and Functional Properties of a New PMMA-ZnO Composite.

In this research work, we synthesised poly(methyl methacrylate) (PMMA) enriched with 2 wt.% zinc oxide nanoparticles (ZnO) through conventional heat polymerisation and characterised its microstructure. It was found that the distribution of ZnO nanoparticles was homogeneous through the volume of the PMMA. The mechanical testing of the PMMA-ZnO composite primarily included the determination of the compressive properties on real dentures, while density measurements were performed using a pycnometer. The testing of functional properties involved the identification of the colour of the new PMMA-ZnO composite, where pure PMMA acted as a control. In the second step, the PMMA-ZnO cytotoxicity assays were measured in vitro, which were shown to be similar to the control PMMA. Based on this, it could be concluded that the newly formed PMMA-ZnO composite did not induce direct or indirect cytotoxic effects in L929 cell cultures; therefore, according to ISO/DIN 10993-5:2009, this composite was categorised as non-cytotoxic.