Zinc Oxide Powder Research Articles

Preparation and characterization of polyvinyl chloride membranes decorated with designed novel zinc oxide particles for mitigating uncontrollable agglomeration

The use of nanomaterials in the fabrication of polymeric composite membranes has a great potential for improving separation performance by altering the membrane characteristics. However, homogeneous dispersion of these fillers in the matrix and stability issues have remained major drawbacks to take a step forward for the commercial applications of such membranes. In this study, polyvinyl chloride ultrafiltration membranes were prepared via direct blending of designed zinc oxide (ZnO) powders (MicNo®), that were intentionally agglomerated in hexagonal platelet forms, into the casting solution by immersion precipitation method. The impact of MicNo® loading on the development of membrane microstructure, separation performance and bulk properties were evaluated in comparison to neat PVC and commercial ZnO-doped membranes. Water flux (456 L/m2h) of the 0.05% wt. MicNo® platelets containing membranes had 30.6% and 9% higher values with respect to pristine PVC and 0.5% commercial ZnO (c-ZnO) containing membranes, respectively. Although the amount of MicNo® platelets (0.05%), added to the membrane casting solution was ten times less than c-ZnO nanoparticles (0.5%), rejection and antifouling properties of the membranes were enhanced significantly due to the large active hydrophilic surface area of MicNo® powders. The highest FRR value after SA removal tests was achieved as 89.9% in the case of PVC/0.05 MicNo® membrane with 19% enhancement compared with the pristine membrane. Overall, incorporating MicNo® into PVC-based membrane matrix could be a promising approach to cope with the uncontrolled agglomeration and leaching issues with minimal embedment of fillers.

Innovative Investigation of Zinc Oxide Nanoparticles Used in Dentistry

Dental caries is a major lifestyle concern as dental components affect the face of an individual. The issue of tooth decay occurs in every age group throughout the globe. Researchers are probing incipient implements and techniques to develop filling agents for decayed teeth. Zinc oxide (ZnO) powder is utilized mostly as a filling agent. Nanotechnology enhanced the efficiency of compounds of metal oxides utilized for dental caries. The present study aims to investigate the properties of ZnO nanoparticles (NPs) synthesized chemically (using ZnCl2 and NaOH) as well as biologically (using aqueous leaf extract of Murraya paniculata). The XRD patterns confirm that ZnO NPs have a hexagonal crystalline structure with particle sizes of 47 nm and 55 nm for chemically and biologically synthesized NPs, respectively. The FE-SEM data confirm the nanorod and spherical/cubical shape morphologies for the chemically and biologically synthesized ZnO NPs, respectively. FTIR data show the peaks between 4000 and 450 cm−1 of the functional groups of –OH, C-O, –C-H-, and Zn-O bonds. The UV–Vis absorption study indicates a peak around 370 nm and a hump around 360 nm corresponding to the chemically and biologically synthesized ZnO NPs, respectively. An antibacterial bioassay was performed and compared with commercially available ZnO bulk powder against tooth decaying pathogens, viz., Streptococcus mutans, Staphylococcus aureus, E. coli, and Lactobacillus fermentum, and found that both ZnO NPs had results closer to those of the standard drug (rifampicin). Thus, the synthesized ZnO NPs may be utilized as nano-drugs for the application of tooth decaying filling agents. Even biologically synthesized ZnO NPs may be considered more environmentally friendly and less toxic to human health concerns.

Triple antibiotic paste and simvastatin in the treatment of non-vital primary molars with inflammatory root resorption


 Aim: This study aimed to compare the success rate of pulp therapy of non-vital primary molars with inflammatory root resorption when treated using triple antibiotic mix or simvastatin as a component in the root filling material. Methodology: Lesion Sterilization and tissue repair was employed in the treatment of 30 non-vital primary molars exhibiting inflammatory root resorption and furcation radiolucency. The molars included in the study were randomly allocated into 2 equal groups. All root canals were instrumented 1mm from the radiographic apex, and an obturation mix was used to fill the canals to avoid the hollow tube effect. Triple antibiotic paste (TAP) was prepared by mixing ciprofloxacin, cefixime, and metronidazole in a 1:1:1 ratio. It was used as the active agent in group I and mixed with zinc oxide powder and polyethylene glycol + propylene glycol as a vehicle to prepare a filling material. For group II, simvastatin was used as the active agent alone. Following pulp therapy, all teeth were restored with stainless steel crowns, 1-week postoperative. Clinical evaluation was carried out at 1 week postoperative, then at 3, 6, and 12 months while radiographic evaluation was carried out at 6 and 12 months using predetermined criteria.

Thin Film Photodetectors Based on Zinc Oxide Nanoinks

Zinc oxide (ZnO) has many useful properties for electronics and optoelectronics including wide band gap, large exciton binding energy, low-cost, ease of processing and availability [1]. This has led to increased interest and development of thin film electronics, transparent conductors, solar cells, light-emitting diodes, lasers, photodetectors and various sensors based on ZnO materials [2, 3]. The high surface areas and tunable properties of ZnO nanostructures make them particularly suitable for applications such as sensing and photonic devices [4, 5].In this work, we present results on nanostructured ZnO thin film photodetectors fabricated using nanoparticle inks (nanoinks) obtained via planetary ball milling (PBM) of bulk powders. PBM [6] is an emerging solution-based nanofabrication approach that can quickly produce nanoink suspensions at low-cost by nanoscale grinding, without complex processing and suitable for thin film coating of various materials on different substrates [7]. The thin film photodetector devices were fabricated by depositing PBM ZnO nanoink onto flat insulating glass substrates followed by contact formation as shown schematically in Fig. 1a: PBM was performed using ZnO powder in ethylene glycol (EG) or deionized (DI) water solvent (a.k.a. colloidal grinding) with zirconia grinding beads. The grinding speed and time were varied between 200 and 1000 rpm and 10 min. and 60 min., respectively. A few μL of the resulting ZnO nanoink was used to coat the substrate surface and dried at ~ 100 °C. Lastly, two electrical contacts to the resulting films were made using silver paint and copper tape. Analysis of ZnO films after deposition showed they consist of nanostructured particles with sizes reaching below 100 nm, as displayed in the scanning electron microscopy (SEM) and atomic force microscopy (AFM) images in Fig. 1b, depending on grinding conditions (speed, time).The optical properties of the ZnO thin films were evaluated via photoluminescence measurements (Fig. 1c), which, in addition to interband transitions in the UV, displayed longer wavelength emission peaks due to surface and bulk defect states. Such deep level states are dependent on grinding parameters and thus allow the accessible spectrum for the nanostructured ZnO films to be extended into the visible region in a tunable manner. Two-terminal photoconductance data of the ZnO PBM nanoink thin film devices were obtained using a probe station and precision source-measure unit, with and without illumination, under ambient atmosphere and at room temperature. Fig. 1d shows current vs. voltage curves obtained for a typical photodetector device, which display current increasing proportional to incident light intensity. This behavior can be explained by electron-hole pair creation and desorption of surface oxygen species (leading to vacancies that act as donors) upon photon absorption, which leads to an increase in conductance. This is consistent with previous studies where ZnO thin films have been used for photoconductive sensor applications, validating PBM nanoink as a suitable synthesis technique for the active material in photodetectors.Compared to standard ZnO thin films, the PBM nanoink method allows both particle dimensions and surface states to be tailored and optimized for different photodetector applications in a straightforward manner by adjusting grinding conditions. In particular, both UV and visible light detection can be tuned via the solution-based ZnO nanoink approach presented without additional material/chemical processing. Such PBM nanoinks thus offer the potential of realizing low-cost photodetectors and multifunctional thin film coatings for applications in optoelectronics, imaging, environmental monitoring and communications.

Photo-supercapacitors based on nanoscaled ZnO

In this study, zinc oxide (ZnO) powders in two different morphologies, nanowire (NW) and nanoflower (NF), have been synthesized by the hydrothermal method. The eligibility of the pristine ZnO nanopowders as a photo-active material has been revealed by designing P-SC devices via the facile drop-casting method on both glass and plastic substrates in large-area applications. The impact of physical properties and especially defect structures on photo-supercapacitor (P-SC) performance have been explored. Although the dark Coulombic efficiency (CE%) of both NW and NF-based P-SC were very close to each other, the CE% of NW P-SC increased 3 times, while the CE% of NF P-SC increased 1.7 times under the UV-light. This is because the charge carriers produced under light excitation, extend the discharge time, and as confirmed by electron paramagnetic resonance, photoluminescence, and transmission electron microscopy analyses, the performance of P-SCs made from NF powders was relatively low compared to those produced from NW due to the high core defects in NF powders. The energy density of 78.1 mWh kg−1 obtained for NF-based P-SCs is very promising, and the capacitance retention value of almost 100% for 3000 cycles showed that the P-SCs produced from these materials were entirely stable. Compared to the literature, the P-SCs we propose in this study are essential for new generation energy storage systems, thanks to their ease of design, adaptability to mass production for large-area applications, and their ability to store more energy under illumination.

The pH dependence of dissolution kinetics of zinc oxide

Zinc oxide (ZnO) powders are used as feed additives for supplementation in diet of animals. Because zinc dissolution rate strongly influences the digestibility of zinc by animals and their stomach has variable pH, the dissolution kinetics of ZnO are studied at the several pH of relevance between 2 and 4. The dissolution of ZnO has been investigated with the help of modeling the dissolution kinetics measured in vitro at various pH. Dissolution is faster in acidic medium. But the acceleration of dissolution at low pH is moderate compared to what would be expected on the basis of the strong pH dependence of ZnO solubility. The concentration of Zn2+ in the quiescent medium at the surface of ZnO particles is much lower than its solubility. It is proposed as a rationale, that hydroxide anions released during dissolution accumulate at the surface of the positively charged ZnO surface, and that the dissolution kinetics is mainly controlled by the diffusion of H+ ions from the bulk solution to the surface.

Использование наноразмерного ZnO в составах для защитной обработки древесины

Wood natural structure can be considered as a suitable matrix for modifying with nanoparticles of various chemical nature. The research aims at obtaining a woodbased nanocomposite by modifying wood with compositions of waste vegetable oil and zinc oxide nanoparticles and studying the properties of this nanocomposite. Silver birch (Betula pendula) wood samples were chosen as study objects. Refined sunflower oil left after cooking was the oil base of the developed impregnating compositions; nanosized zinc oxide powder was the filler and modifier. The sol-gel method providing a narrow range of particle size distribution was used for synthesis of zinc oxide nanoparticles from Zn(NO3)2·6H2O as starting material. Aqueous ammonia solution was used as a precipitant. The synthesized zinc oxide nanoparticles contained no impurities, were mostly spherical and had the size less than 20 nm. The size of zinc oxide agglomerates was no more than 100 nm, allowing them to easily penetrate into the wood material cavities. A stable suspension of synthesized zinc oxide nanopowder in used sunflower oil was prepared and applied for wood modification by hot-and-cold bath treatment. It was found that the use of nanoscale zinc oxide accelerates the drying process of vegetable oil coating, increases the strength of such a coating and its resistance to external influences. The use of developed compositions improves the hydrophobic properties of wood, its moisture and water resistance, as well as reduces swelling in the tangential and radial directions. We have chosen the optimal dosage of nanosized zinc oxide (0.1 %) in compositions based on waste vegetable oil for protective treatment of birch wood. Impregnating compositions on the base of waste vegetable oil are environmentally safe and their use allows recycling food industry wastes.

The effect of high-temperature nanoparticle-based modification on the structure of zinc oxide powders

The authors have studied the effect of solid-state nanoparticle-based modification on the structure of zinc oxide powders. To carry out the experiment, seven types of nanoparticles of various oxides were applied. The modification was performed by heating the powder mixtures in the air at 650°C for 2 hours. The concentration of nanopowders was 10 wt.%, the average grain size of nanoparticles varied from 10 to 80 nm. It was established that high-temperature nanoparticle-based modification does not lead to significant structural changes and cannot affect the properties of zinc oxide powder. While modifying zinc oxide powders, an increase in photo- and radiation stability can occur primarily because of mechanisms associated with the deposition of nanoparticles on the surface of the micropowder. Due to structural changes, certain types of nanoparticles (e.g., alumina in the sample under investigation) can make a rather insignificant contribution to the stability of optical properties when exposed to radiation.

Estimate Zinc-Oxide Particles on PMMA Mechanical Properties

Background: Poly-methylmethacrylate is the most used dental material for the construction of removable prosthodontic appliances. Unfortunately, it has shown to be lacking two important properties which are radio-opacity and mechanical strength. Zinc-oxide (ZnO) powder is widely used in dentistry and is considered a semiconductor material with the radio-opaque property. Purpose: To determine the effect of ZnO filler powder on some mechanical properties (impact and transverse strength) of microwave-cured acrylic denture base. Approach: The ZnO powder was added to the acrylic polymer powder in two percentages of 2% and 4% by weight. The prepared sample of acrylic resin was evaluated with impact and transverse strength (n=10). ANOVA and Tukey test were used at a P-value of (P≤0.05). Results: Significant reduction in the transverse strength was noticed in the acrylic denture base with the incorporation of ZnO powder as a filler material in both concentrations. However, non-significant differences were observed in the impact strength with the incorporation of the ZnO filler agent. Conclusions: The addition of ZnO radio-opacifier powder as a filler agent could affect the properties (impact and transverse strength) of microwave-cured acrylic resin.

Control over the Surface Properties of Zinc Oxide Powders via Combining Mechanical, Electron Beam, and Thermal Processing.

The surface properties of zinc oxide powders prepared using mechanical activation, electron beam irradiation, and vacuum annealing, as well using combinations of these types of treatments, were studied using X-ray photoelectron spectroscopy. The structure of the obtained materials was studied by an X-ray diffraction technique and by scanning electron microscopy. We found that over five hours of grinding in an attritor, the size of nanocrystals decreases from 37 to 21 nm, and microdeformations increase from 0.3% to 0.6%. It was also found that a five-hour grinding treatment promoted formation of vacancies in the zinc sublattice at the surface and diffusion of Zn2+ cations into the bulk of the material. Irradiation of commercial zinc oxide powders with an electron beam with an energy of 0.9 MeV and a dose of 1 MGy induced breaking of Zn–O bonds, diffusion of interstitial zinc ions into the bulk, and oxygen atom escape from regular positions into the gas phase. A combined treatment of five hours of grinding and electron beam irradiation promoted accumulation of interstitial zinc ions at the surface of the material. Annealing of both initial and mechanically activated ZnO powders at temperatures up to 400 °C did not lead to a significant change in the properties of the samples. Upon exceeding the 400 °C annealing temperature the X-ray photoelectron spectra show almost identical atomic composition of the two types of materials, which is related to diffusion of interstitial zinc ions from the bulk of the material to the surface.

Enhancing mechanical and antibacterial properties of polycaprolactone nanocomposite nanofibers using decorated clay with ZnO nanorods

AbstractIt is urgently necessitate to develop a construct with desirable mechanical properties and antibacterial activity for biomedical applications. Zinc oxide (ZnO) has emerged as a promising antibacterial inorganic agent for the improvement of biopolymer scaffold properties. However, its agglomeration/aggregation has an adverse effect on its performance. In the present work, clay platelets have served as a substrate for decoration of high density, well‐distributed ZnO nanorods via in‐situ synthesis. Then, polycaprolactone (PCL) nanofibers containing 1%, 2%, 4%, and 6% ZnO nanorods decorated on clay platelets (Clay@ ZnO) are fabricated using the electrospinning technique. The tensile strength and modulus of the PCL scaffold are significantly enhanced by increasing Clay@ ZnO content, thanks to the presence of well‐distributed ZnO rods on exfoliated clay platelets. However, the maximum elongation at break is observed for PCL/1% (Clay@ ZnO). Disc diffusion method reveals that good coverage of clay platelets with ZnO nanorods boosts the antibacterial performance of ZnO against both Staphylococcus aureus and Escherichia coli bacteria strains. Moreover, incorporation of Clay@ ZnO powders into the PCL scaffold considerably enhances its antibacterial activity. Cell culturing assay demonstrates the favorable cytocompatibility of prepared nanocomposite nanofibers by promoting cell attachment and proliferation. Such engineered nanocomposite has a high potential to utilize in biomedical applications.

Synthesis and characterization of ZnO based varistor ceramics: effect of sintering temperatures

PurposeThe purpose of this paper is to investigate the effects of the sintering temperature on the microstructural, morphological and electrical characteristics of Zinc oxide (ZnO)-based varistors.Design/methodology/approachThis study used a conventional method to design and produce ZnO varistors by sintering ZnO powder with small amounts of various metal oxides. Furthermore, the effect of sintering temperature on varistor properties of (Bi, Co, Cr, Sb, Mn)-doped ZnO ceramics was investigated in the range of 1280–1350 °C.FindingsThe obtained results showed an EB value of 2109.79 V/cm, a Vgb value of 0.831 V and a nonlinear coefficient (α) value of 19.91 for sample sintered at temperature of 1300 °C. In addition, the low value of tan δ at low frequency range confirmed that the grain boundaries created in 1300 °C sintering temperature were obviously good.Originality/valueBased on the previous research on the ZnO-based varistors, a thorough study was carried out on these components to improve their electrical characteristics. Thus, it is necessary that those varistors have low leakage current and low value of dissipation factor to ensure their good quality. High breakdown fields and nonlinearity coefficients are also required in such kind of components. The effect of sintering temperature on the varistor properties of the new compositions (zinc, bismuth, manganese, chrome, cobalt, antimony and silicon oxides)-doped ZnO ceramics was studied in the range of 1280–1350 °C. Also, the microstructure and the phase evolution of the samples sintered at various temperatures (1280 °C, 1300 °C, 1320 °C and 1350 °C) were investigated according to X-ray diffraction and scanning electron microscope measurements.

Morphological and chemical evolution of transient interfaces during zinc oxide cold sintering process

Although zinc oxide has a high melting point of 1975 °C, the recent development of the cold sintering process has shown that highly dense polycrystalline ceramics can be obtained at 150 °C or below. As such unusual densification does not yet have fully elucidated underlying mechanisms, this study aims to provide a comprehensive investigation of transient morphological and chemical interfaces during isothermal dwell. The chemical “transient” interface involves the formation of a zinc carboxylate complex by reacting the host zinc oxide powder and acetic acid solution, which is later consumed for the recrystallization on the lattice of an adjacent grain with a decomposition of the complex. Hence, the final outcome can be a residual-free zinc oxide phase. Regarding the morphological evolution, gas physisorption studies were conducted to quantify the area of solid–vapor interfaces and the Schlaffer model was used to analyze the activation energy for specific surface area reduction. Moreover, transmission electron micrographs revealed that the recrystallization occurs at the interface between crystalline grain and carbon-rich amorphous phase. After 30 minutes of isothermal dwell, the area of the amorphous phase was significantly decreased while grain size was increased, potentially indicating the recrystallization-induced grain growth and pore closure. The chemical transition at the zinc oxide surface was further investigated using ReaxFF molecular dynamics simulation, observing that acetate molecule acts as a bridging complex to connect zinc ions to the surface. Overall, understanding the evolution of the transient interface is a crucial subject to obtaining a residual-free cold-sintered sample with desired grain size and properties for application developments.

LOW TEMPERATURE COMBUSTION SYNTHESIS AND CHARACTERIZATION OF UNDOPED AND SAMARIUM DOPED ZINC OXIDE NANOPARTICLES

Zinc oxide (ZnO) and samarium (Sm) doped ZnO nanoparticles (NPs) were synthesised by solution combustion approach using citric acid as fuel. The formation of hexagonal wurtzite structure of pure and Sm doped ZnO powder was prepared and confirmed by x-ray diffraction (XRD). The structure formation, morphological and elemental analysis of pure and Sm doped ZnO powder were analysed using XRD, Raman spectra, scanning electron microscopy (SEM) and xray fluorescence spectroscopy (XRF). The results indicated that the trivalent Sm ions were successfully doped in to the lattice of ZnO matrix. The XRD images showed that both ZnO and Sm doped ZnO NPs are highly crystalline, having hexagonal wurtzite structure.

An Innovative Solid-State Approach to Zinc Orthostannate: Remarkable Sintering Temperature Reduction via Lithium Doping and Mechanochemical Activation of Low-Melting Precursors

Zinc orthostannate, often called zinc tin oxide (ZTO), possesses unique physical characteristics and is a promising wide band gap (3.6 eV) n-type semiconductor material for a broad range of applications. The standard solid-state fabrication of ZTO requires prolonged heat treatment of zinc oxide and stannic oxide powders at around 1000 °C. The biggest drawback of this process is the evaporation of zinc oxide during the synthesis. We report an innovative and efficient mechanochemically supported solid-state approach to Li-doped ZTO synthesis with the implementation of a low-melting lithium hydroxide sintering aid, which offers a significant lowering of the sintering temperature down to 850 °C and time to 90 min, maintaining the high quality of the resulting Li-doped ZTO materials. The effect of sintering temperatures in the range 850–900 °C on photoluminescence characteristics of the ZTO materials was studied, and the PL spectra well corroborate with the XPS data and the presence of O as well as Zn or Sn vacancies. The band gap value of the resulting ZTO materials oscillated around 3.6 eV. Moreover, a comprehensive spectroscopic and microscopic examination of the optimized Li-doped ZTO materials provided more profound insight into its vacancy-mediated formation via liquid-phase sintering and its gradual advancement in the low-temperature regime of 850–900 °C. Additionally, the surface analysis of the selected highest quality materials enabled the determination of the Zn diffusion from the Li-doped ZTO lattice to its surface, expanding the knowledge of the diffusion–evaporation process.

Synthesis and characterization of ZnO nanoparticles for the production of biodiesel by transesterification: Kinetic and thermodynamic studies

Under sol–gel conditions, a stable zinc oxide powder with nanoparticle morphology was synthesized utilizing zinc nitrate as a precursor, EDTA as a complexing agent, and citric acid as a stabilizing agent. Zinc oxide nanoparticles were characterized utilizing XRD, SEM, BET, EDXRF, FT-IR, and UV–Vis techniques. The catalytic activity of the ZnO nanoparticle catalyst was successfully evaluated by carrying out a transesterification reaction in sunflower oil (SFO). To establish the optimal conditions for biodiesel synthesis, the transesterification process was carried out under various reaction parameters. Several oil-to-metal ratios (1:10, 1:20, and 1:30) were investigated at various times ranging from 1 to 4 h in a reaction operated at temperatures of 60, 65, and 70 °C. The results indicate that ZnO catalysts show good performance in biodiesel production from sunflower oil and provide a biodiesel yield of 71%. under optimal reaction conditions, i.e., methanol to oil molar ratio of 20:1, catalyst amount of 4.7 wt%, and a reaction temperature of 70 °C for 3 h. The catalytic activity can be attributed to the existence of an optimal number of catalytically active sites on the surface of the catalyst. The composition analysis of the synthesized biodiesel was studied using different characterization techniques, such as GC–MS and FT-IR, to identify the FAMEs. The kinetics of the transesterification reaction indicate a pseudo-first-order reaction, and the rate of the reaction is calculated. Thermodynamic functions such as activation energy, heat content, entropy, and Gibbs free energy were determined. The physical and chemical properties of synthetic biodiesel, such as density, viscosity, flash point, pour point, acid value, and water content, were studied and compared against international standards.

ZnO Powder Nanostructures: Characterization and <i>Ab Initio</i> Study

This work presents the structural and microstructural properties of zinc oxide (ZnO) powders, for that, we used X-ray diffraction (XRD), Optical microscope as characterization methods. Powder X-ray diffraction data confirm a hexagonal crystal structure formation with space group p63mc of ZnO. By Rietveld refinement, we have determined the microstructural parameters with the c axis of the preferential orientation, the ZnO replicas were clearly observed under an optical microscope. Band structure and density of states of the phase of crystal ZnO computed using Ab Initio methods, confirmed that pure ZnO is a direct band gap semiconductor in hexagonal wurtzite structure.

Facile Low-Cost Synthesis of Highly Photocatalitycally Active Zinc Oxide Powders

The industrial waste can cause significant harm to human health and to the environment. Organic dyes in particular are environmentally dangerous since they may cause the death of aquatic life or contaminate the feed chain. Thus, one of the current research fields consists of the development of an inexpensive and environmentally friendly method to purify wastewater from organic contaminants. Among the others, Zinc oxide (ZnO) is considered one of the most effective photocatalysts for the decomposition of organic pollutants in water. In this work, we developed a highly efficient low-temperature and environmentally safe synthesis method to obtain photocatalytically active nanostructured ZnO by chemical precipitation from a solution. The effect of the technological conditions of synthesis on the photocatalytic properties is considered in detail, the correlation with the morphology, structural, and optical properties of the synthesized ZnO samples is determined. It was found that the maximum photocatalytic activity with respect to the decomposition of the dye rhodamine-B (RhB) is achieved for samples synthesized at NaOH molar concentration from 0.4 to 0.7 M; in this case, the sizes of crystallites along the crystallographic direction 002 reach maximum values of ∼42 nm. On the contrary, the sizes of crystallites along the directions 100 and 101 decrease monotonically from 30 to 25 nm with an increase in the molar concentration of NaOH from 0.14 to 1 M.

Tragia involucrata Leaf-Mediated ZnO NPs: Biomedical Applications, Ointment Formulation and Electrochemical Studies.

Zinc oxide (ZnO) NPs, owing to their broad biomedical applications, have recently attracted the scientific community with incredible interest as therapeutic agents. So, the present study aims at preparation of ZnO NPs, using Tragia involucrata leaf extract and exploring their capability as antioxidant, anticancer and anti-inflammatory agents. Besides, the ointment formulation and electrochemical studies were also carried out in this work. The antioxidant activity of the synthesized ZnO NPs was evaluated using DPPH assay method and the results clearly showed higher inhibition of about 70% and lower inhibition of about 14% for 100µg/ml and 25µg/ml concentrations, respectively. The cytotoxic effects of ZnO NPs were evaluated against human cancer cell lines such as A549 (lungs), HeLa (cervical), HeP-2 (laryngeal) and MCF-7 (breast). The outcome of this investigation confirmed the effectiveness of the synthesized NPs against HeP-2 even at the lowest concentration. The anti-inflammatory activity was measured by the inhibition of protein denaturation assay. A higher inhibition of about 54% was noticed at the concentration of 100µg/ml. In the case of the ointment formulation study, the pastes prepared using the biosynthesized ZnO NPs and commercially available ZnO powder were compared and evaluated using the parameters such as pH, spreadability, moisture content, extrudability, foamability and physical examinations. As it has been noticed that all the observed parameters were matching well with those of the commercially available ZnO powder, ZnO NPs, synthesized using Tragia involucrata, may be suggested for the clinical trials. Cyclic voltammetry was used to measure the specific capacitance of the synthesized ZnO NPs for different scan rates. The results of this study showed the gradual decrease in specific capacitance value for the corresponding increase in scan rates. Therefore, the results of present study indicated that ZnO NPs prepared using Tragia involucrata leaves were found to be effective for all the above chosen applications and hence, have multifunctional capacity.

Effect of TiO2 and ZnO powder mixtures on mechanical and photocatalytic performance of high performance concrete

The development of new modified cement-based materials is increasingly becoming a necessity for improving the durability and surface performance of building materials. Titanium dioxide (TiO2) photocatalyst has been widely used in building materials science due to its ability to break down pollutants. Zinc oxide (ZnO) is often considered a substituent for TiO2 because of its photocatalytic and photoluminescent properties. A new inorganic nanocomposite photocatalyst, based on titanium and zinc oxides, is introduced in this work in order to study its compatibility with High Performance Concrete (HPC). This research aims to study the mechanical and photocatalytic behavior of mixtures based on nanoparticles in HPC. The study of the efficiency in the nitrogen oxides (NOx) degradation of modified HPC in TiO2 and ZnO with different percentages is studied. The studies have shown that the introduction of titanium dioxide in HPC presents a significant efficiency for the NOx degradation and a positive effect on the mechanical properties than zinc oxide, and thus represents potential contribution to sustainability of concrete structures.