Papers by Keyword: Nanomaterials

Abstract: Raw pumice samples were modified with nano carbon black, borax, and nano carbon-borax using the sol-gel method by applying surface modification processes, and the changes in the thermal behavior of the surface modification of the raw pumice were studied by characterizing them with FE-SEM, EDX, FT-IR, XRD, BET and TGA-DTA. In the analyses made with FE-SEM, it was observed that the surface and pore structure of the raw pumice changed after the modified process, and in the EDX analysis, it was determined that nano carbon black and borax adhered to the surface of the raw pumice. In the XRD results, no change in the crystal structure of the raw pumice was observed after the modified treatment. TGA-DTA analysis showed that the mass loss of raw pumice (P) was greater than pumice-nano carbon black (PC), pumice-borax (PB), and pumice-borax-nano carbon black (PBC). Accordingly, raw pumice showed a mass loss of approximately 25%, pumice-borax (PB) and pumice-nano carbon black (PC) 0.45%, and pumice-borax-nano carbon black (PBC) nearly 3%. According to the BET analysis results, it was determined that the raw pumice has a surface area of 28.126 m²/g. After the surface modification process, the surface area of the raw pumice was determined as 52.127 m²/g in the pumice-nano carbon black sample, 49.125 m²/g in the pumice-borax sample, and 32.523 m²/g in the pumice-borax-carbon black sample. Considering the data obtained, the best surface properties were showed in pumice-nano carbon black (PC). Research results showed that; the modification process with nano carbon black and borax changed the thermal behavior of raw pumice.

Abstract: Using a facile hydrothermal method, ZnO nanomaterials with various morphological structures (nanowires, nanodiscs, and nanostars) were produced. An investigation was conducted into the relationships between the exposed polar facets and the photocatalytic activities. Based on XPS, Pl, and structural analysis, it was discovered that the exposed facets’ chemsorption ability of the different ZnO nanomaterials with different morphologies plays a vital role in their photocatalytic properties. Zinc-terminated surfaces had the highest chemsorption ability and consequently the ZnO nanodiscs with the highest fraction of exposed Zinc-terminated facets were the ideal photocatalysts from the tested morphologies. This work emphasises the important influence of rational control over the nanomaterial morphology on its physical and chemical properties and therefore on its performance in various practical applications.

Abstract: Liquid crystal-quantum dot (LC-QD) composites are promising new materials for a number of applications in displays, energy harvesting, and photonics. In the present work, quantum dispersion in the mixture of LCs of cholesteric and nematic phases is reported. The combination of two LCs, namely Cholesteryl Palmitate (cholesteric 97%) and 4′-Pentyl-4-biphenylcarbonitrile (nematic, 98%), were used in equal proportion while CdS quantum dots were added in this mixture. The thermal, optical, and structural properties of this new LC-QD composite system were analyzed using differential scanning calorimetry (DSC), ultra-violet visible (UV-VIS) spectroscopy, Fabry-Perot scattering studies (FPSS), and Fourier transform infrared (FTIR) spectroscopy. Structural studies indicate that the QDs are uniformly dispersed inside the LC matrix rather than on the surface area. It was observed that quantum dot dispersion increases the strength of the LC mixture. It also changes the phase behavior of the LC mixture affecting the overall performance of LC-QD composite systems. The present findings would be very helpful for the design of the display and photonic devices with an improved optical response.

Abstract: The improved oil recovery (IOR) is a way of enhancing the reservoir properties with the use of nanomaterials to detach the oil molecule from the trapped zone. The polarization effect on reservoir sandstone under an electric double layer is one of the major research interests. The nanoparticles agglomeration such as graphene nanofluid due to poor dispersion in reservoir zone can be a major challenge that can lead to low reservoir permeability are well elucidated. This study investigated the influence of graphene nanofluid on the ionic polarization under an electric double layer in reservoir sandstone. Saturated Berea sandstone was used to investigate the interaction of ionic species on reservoir sandstone with the aid of Field-emission microscopy (FESEM), Energy dispersive X-ray mapping (EDX), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectral analysis, and Core flooding experiment. This research gives information on the adsorption of ions within an electric double layer and its polarization mechanisms. It was revealed from the experimental result that ionic polarization occurs at 9.97 GHz with a 5.8nm wavelength shift which improves the mobility of the reservoir and in turn increases oil recovery factors. Graphene nanoparticles show a positive effect on both reservoir oil viscosity and stabilization characteristics of drilling fluids, wettability alteration, interfacial tension, and improving the emulsion Keywords: Nanomaterials, Sandstone, Electric double layer, Graphene

Abstract: The preparation of hydroxyapatite nanopowders in this experiment demonstrated a novel method for milling of animal bone powder to nanoparticle size prior to calcination. The buffalo bone was deproteinized by hot water before it was dried at 200°C for 24 h. The resulting product was crushed into small pieces and milled in a ball mill pot for 24 h. After that, the bone powders were ground by a high speed vibro-milling method with various milling times. Characteristics of the powders were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS). The experimental results of SEM showed that the shape of the buffalo bone particles was regular with the particle size less than 100 nm from using high speed vibro-milling time of 2 h. The buffalo bone nanopowder were calcined at various temperatures. XRD and SEM results showed that material obtained is a HA according to JCPDS file-9432 pattern in a 1.66 Ca/P molar ratio at calcination temperature of 600°C. The average diameter of powder less than 100 nm.

Abstract: A well-controlled multistage hydrothermal technique was developed to synthesise hierarchical zinc oxide (ZnO) nanomaterials with a high surface-to-volume ratio. Hierarchical ZnO nanomaterials, hierarchical nanowires (HNWs) and hierarchical nanodiscs (HNDs), assembled from initial mono-morphological nanomaterials, ZnO nanowires, and ZnO nanodiscs respectively were prepared by sequential nucleation and growth following a hydrothermal course. The hierarchical nanomaterials composed of one-dimensional nanowire building blocks were obtained by introducing zinc nitrate as a source of zinc ions during the second growth phase. In comparison to their initial monomorphological counterparts, the prepared HNWs and HNDs showed superior photocatalytic performances. The improvement in the photocatalytic performance was ascribed to the reduction in dimensionality, the ultrahigh surface-to-volume ratio, the expanded proportion of the exposed polar area, and the creation of nanojunctions between the secondary nanowires and initial ZnO nanowires or nanodiscs. This work paves the way for the low-cost, large-scale, and low-temperature production of ZnO nanomaterials with superior photocatalytic properties.

Abstract: In recent times, much attention has been drawn to the synthesis of carbon dots from agro waste since they are a cheap source, readily available, non-toxic and in most instances disposed of as waste. Yet, the synthesis of fluorescent carbon dots at low temperatures from agro waste remain a challenge. Herein, we report for the first time on a sucessful synthesis of flourescent carbon dots, with average size 4.7 nm, at low temperature of only 100 °C using hydrothermal method from pomegranate peels as a sole precursor. The crystal structure and the morphological features of the synthesized dots were characterized by XRD, UV-vis absorption spectroscopy, photoluminescence (PL), nanosecond fluorescence lifetime, FTIR and Zeta potential measurments. The synthesized dots showed bluish emission at 440 nm, when excited at a wavelength of 360 nm, with relatively long decay lifetime of 7.4 ns.

Abstract: Flame Spray Pyrolysis is an attractive technology for the synthesis of nanosized materials with distinct characteristics. Industry leaders such as Cabot, Cristal, DuPont, Evonik, and Ishihara manufacture flame-made materials in millions of tons per year including carbon blacks. Herein we exemplify the application of large-scale FSP process for the synthesis of highly active photocatalysts, able to achieve high H₂, O2 production yields from H₂O. Precise control of W-doping along with controlled Scheelite-phase BiVO₄ is a benchmark oxygen-evolving nanocatalyst. Double-Nozzle FSP is demonstrated to allow the production of highly efficient {noble metal} TiO₂ heterostructures. Key-Performance-Indicators that allow transition of Lab-Scale to Industrial-Scale engineering of semiconductors are discussed, including cost-analysis and environmental impact of the production process.

Abstract: Bio-fuel is world's best substitutes to petroleum fuels, particularly in developing countries, especially in present situation, in which fossil fuels are rapidly decreasing. By emitting greenhouse gases when fossil-based fuels are burned, they pose a serious danger to the environment and human health. Bio-fuel production on a large scale requires longer time and activity due to many constraints in currently available technology and supplementary increased costs. Furthermore, depending on the techniques and materials used, the procedures used to convert diverse feed stocks to the intended output are varied. Nanoparticles (NPs) are one of the most versatile materials in terms of time management, energy efficiency, and selectivity. It is the best way to address the issues of biomass usage. Lots of technology has implemented based on nanoparticles includes metal oxide and magnetic oxides, are engaged to progress bio-fuel production. NPs are useful biofuel additives because of their stability, higher surface area, reusability and catalytic activity. Furthermore, nanomaterials include carbon nanofibers, nanosheets and carbon nanotubes have been discovered to be a stable catalyst for enzyme immobilisation, resulting in improved bio-fuel production. The current research provides a thorough examination of the utilisation of different nanocomposites for bio-fuel production, as well as the significant hurdles and potential prospects.

Abstract: The new update in advancement in nanotechnology has engaged to develop a new nanomaterial with a different functional property. The morphology modification of nanoparticles has exhibited excellent physio-chemical properties such as high reactivity and absorption rate, photochemical and magnetic property, and larger surface area. Moreover, biomedical application of nanoparticles are yet a hard tool to use for therapeutic application owing to its limits such as Pitiable target specificity, bio-compatibility, low photostability, toxicity to organically, poor blood retention and cellular absorption. Therefore advancement in nanotechnology is required to overcome these defects. In this background, new nanomaterials are identified with suitable biological, chemical and physical properties, which suits the required demands of the application. In this mini-review, we have covered the recent focuses of nanomaterials for biomedical application.