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  • Open access
  • 27 Reads
Biosynthesis of Titanium Dioxide Nanoparticles by the aqueous extract of Juglans regia green husk

The biosynthesis of nanoparticles as a green synthesis method is a simple, non-toxic, economical and eco-friendly approach to the synthesis of nanoparticles. In this research, nanoparticles of titanium dioxide (TiO2 NPs) were synthesized using an aqueous extract of Juglans regia (J. regia) green husk. Walnut green husk is an agricultural waste that could be a rich source of valuable compounds. The potential of this low-cost natural material as a source of phenolic compounds with antiradical and antimicrobial activities has been demonstrated by several studies. The UV-vis spectroscopy, X-ray diffraction, FT–IR spectrum, dynamic light scattering, and field emission scanning electron microscopy (FESEM) analyses were carried out to characterize the NPs. The UV–visible spectrum shows a strong absorption peak at a wavelength of 330 nm. The synthesized TiO2 nanoparticles have anatase phase with an average size of 20–37 nm. The Ti-O bonding was recognized by FTIR analysis. The spherical surface morphology and their Ti and O elemental configurations were characterized by FESEM and EDX respectively. TiO2 NPs are considered extremely valuable nanomaterials because of their nontoxicity, high stability and photocatalytic activities. Therefore, TiO2 NPs are useful in cosmetics, chemical sensing, wastewater treatment, antimicrobial applications, hydrogen production and lithium-ion batteries.

  • Open access
  • 20 Reads
Tuning the Electronic Properties of Janus GeSnS Monolayers through Strain and Electric Field

This study investigates the electronic properties of a single layer of the novel Janus material GeSnS using density functional theory. By utilizing the hybrid functional HSE06 in addition to the standard PBE approximation, the study aims to obtain accurate findings about how changes in strain and electric field affect the material's electronic properties. The results of the study reveal that the natural energy bandgap of the GeSnS monolayer is 2.2 eV and that it exhibits an indirect band gap behavior. The study also shows that by applying strain or an electric field, the bandgap of the material can be changed, which has significant implications for the material's potential applications. The study found that when strain is applied, the bandgap changes significantly, and a band shift occurs under certain conditions. The band gap energy increases with tensile strain while decreasing with a compressive one. Furthermore, the study discovered that the electric field has a slight effect in changing the bandgap of GeSnS monolayer when the electric field is changed from 0 to 8 V/ang. These findings suggest that GeSnS could be a promising material for applications such as solar cells and optoelectronics, where the bandgap needs to be adjusted for optimal performance. The ability to tune the bandgap of the material through strain or electric field could also be beneficial in other fields such as electronics, spintronics, and quantum computing. The study provides valuable insight into the potential of GeSnS and opens the door for further research in this field.

  • Open access
  • 8 Reads
implantation of electrons in the glass

The objective of our work is to study the behavior of the glass subject to electronic bombing.In the context of this work we first studied theoretically the establishment of electrons in a material in this case the glass. This last which has become a powerful technique to synthesize nanoparticles buried in a material,We postpone the penetration of the electrons according to their acceleration and the density of the material, then we establish the electric field within the material according to the fluence, we thus refer the conditions of destruction of the materialWe highlight that glass can reach a certain load allowing it to destroy it. The value of the disruptive field is between [0.5 to 1.5 mv cm-1]In a second step we are interested in the realization of an electron cannon in order to provide a bundle of focused and energy electrons, more precisely we discuss on this basis the practical design of the latter made up of three important elements a filament of Tungsten, Wehnelt cylinder and anode.In this instrument the electrons are accelerated under high tension a few thousand volts up to 1 MEV. We postpone in this work the thermogal current as a function of the tension, and we discuss the assembly chosen.

  • Open access
  • 14 Reads
Production of low-cost nano-functionalized bacterial cellulose films for smart/intelligent packaging

Petroleum derived polymers such as polyethylene and polypropylene are commonly used in food packing industries while knowing the fact that these polymers cause serious threat to the ecosystem. Therefore, the development of low-cost, environmental friendly and biodegradable polymer to address these issues is an urgent need of the hour. Among various natural polymeric materials (polysaccharides, proteins, polyesters, and polylactides), bacterial nanocellulose (BNC) with extraordinary and differentiated properties is gaining special attention in food packaging industry. The BNC has several advantages over the plant-derived cellulose in terms of higher crystallinity (84-89%), excellent chemical purity i.e. free of hemicellulose, lignin, pectin, high tensile strength, improved water holding capacity, and moldability. Komagataeibacter (formerly Gluconacetobacter) is reported to be the best producer of BC in aerobic fermentation process. The main shortcoming of this process is the high cost of substrates which accounts 70-80% of the total production cost. To reduce the cost several low-cost substrates are utilized for production of BNC. In the addition to biodegradability, the modern-day food packaging system also notify the consumer about the quality of food and its suitability for consumption. In order to achieve this, smart packaging systems based on halochromic materials or colorimetric indicators are developed to monitor real-time freshness of food. These colorimetric indicators are sensitive to change in pH and/or chemical composition of the packaged food. This will help the consumer to easily identify the fresh food from the spoiled ones without opening the package. In addition to this, the colorimetric indicators obtained from natural source are devoid of toxicity and retains antimicrobials/antioxidants activities that can further enhance capability of packaged food from spoilage during storage. Therefore, the present study is focused on the production of low-cost BNC and its subsequent functionalization for smart packaging applications.

  • Open access
  • 20 Reads
Biopolymers-lipid hybrid cubosome for delivery of acemannan

In the last decades, the pharmaceutic industry has shown great interest in new products for drug delivery, since the studies with drug nanocarriers evidenced the application potential of these systems. A relatively new strategy for nano drug deliver is the use of cubosomes, which is a nanoparticle with crystalline structure formed by lipid bilayer created for instance with monoolein lipid and Pluronic F127 as a stabilizer. The internal crystalline structure with hydrophobic region in the acyl region of lipid bilayers plus hydrophilic region provided in the water labyrinths, provides relatively high surface area for encapsulation of diverse drugs and bioactives. In our studies we develop a cubosomes containing biopolymers-shell for the delivery of acemannan as a bioactive extracted from aloe vera, which has immunomodulation properties. The cubosome was produced using 45mM of monoolein and Pluronic F127 at 7% w/w, adding aqueous solutions of chitosan-N-arginine, alginate and acemannan. The mixture was subjected to 10 times mixing (1min) and bath sonication (5min) following our previously described protocols. The samples were studied by means of dynamic light scattering, zeta potential and isothermal titration calorimetry to evaluate the thermodynamic interaction of the hybrid cubosomes with liposomes produced with POPG, as a model cell membrane, in different pH conditions. The encapsulation percentage and delivery profiles of acemannan were besides accessed through spectrophotometry techniques. The encapsulation of acemannan was highly effective and delivery was attenuated and sustained, further suggesting the potential of the hybrid cubosome as a bioactive delivery system. The interaction of the hybrid cubosome with liposomes, evidenced by thermodynamic results, was favored in two different pHs (2.5 and 7.4). The hybrid cubosomes present different physicochemical characteristics depending on pH, which play a role in the enthalpic and entropic contributions during the interaction. Overall, the results indicate potential of the hybrid cubosomes for oral administration of acemannan.

  • Open access
  • 14 Reads
Characterization and comparison of WO3 with hybrid Mo-WO3 and TiO2 with hybrid Zn-TiO2 nanostructures as a photoanodes

Tungsten oxide (WO3) and zinc oxide (ZnO) are n-type semiconductor with numerous applications in photocatalysis due to its abundance, non-toxicity, versatility and photoelectrical properties. The objective of this study is to synthesize and characterize different types of nanostructures (WO3, hybrid WO3-Mo, TiO2 and TiO2-Zn) for a comparison of hybrid and pure nanostructures in order to use them as a photoanodes for removing emerging contaminants from wastewater by photoelectrocatalysis (PEC).

WO3 nanostructures were synthesized using electrochemical anodization in acidic electrolytes. In order to improve the properties of WO3 nanostructures, different concentrations of sodium molybdate were added to the electrolyte to create hybrid WO3-Mo nanostructures. Furthermore, TiO2 nanostructures were synthesized by anodization method in a fluoride electrolyte and following the same procedure mentioned above, TiO2-Zn nanostructures were obtained by adding different concentrations of zinc nitrate to the electrolyte. In all cases, an annealing treatment was carried out after the anodization process.

With the aim of analyzing accurately and comparing the properties of both samples, Field Emission Scanning Electron Microscopy (FE-SEM) and Confocal Laser-Raman Spectroscopy have been used to study the morphology and composition and crystallinity, respectively. Finally, water splitting measurements were performed using the synthesized nanostructures in order to compare the photoelectrochemical properties of the photoanodes.

  • Open access
  • 18 Reads
Metallocenes inside single-walled carbon nanotubes

Metallocenes inside single-walled carbon nanotubes (SWCNTs) are very promising topic of research. The filled SWCNTs can find applications in nanoelectronics, construction materials, spintronics, magnetic storage devices, magnetic recording devices, solar cells and light emission. Starting the first study [1], metallocenes were incorporated inside SWCNTs using different techniques with gas, liquid phase [2,3]. The gas phase includes the evaporation of metallocene with carbon nanotubes. The liquid phase filling includes dissolving the metallocene in organic solvents and mixing with carbon nanotubes [4]. There are many stages of filling with multi-step cleaning and separations. The filled SWCNTs are investigated with Raman spectroscopy, optical absorption spectroscopy, near edge X-ray absorption fine structure spectroscopy, and photoemission spectroscopy [5,6].

[1] Guan L.H., Shi Z.J., Li M.X., Gu Z.N. Ferrocene-filled single-walled carbon nanotubes. Carbon. 2005. V.43. N.13. P.2780-2785.

[2] Li L.J., Khlobystov A.N., Wiltshire J.G., Briggs G.A.D., Nicholas R.J. Diameter-selective encapsulation of metallocenes in single-walled carbon nanotubes. Nature Materials. 2005. V.4. N.6. P.481-485.

[3] Liu X.J., Kuzmany H., Saito T., Pichler T. Temperature dependence of inner tube growth from ferrocene-filled single-walled carbon nanotubes. Physica Status Solidi B-Basic Solid State Physics. 2011. V.248. N.11. P.2492-2495.

[4] Shiozawa H., Giusca C.E., Silva S.R.P., Kataura H., Pichler T. Capillary filling of single-walled carbon nanotubes with ferrocene in an organic solvent. Physica Status Solidi B-Basic Solid State Physics. 2008. V.245. N.10. P.1983-1985.

[5] Plank W., Pfeiffer R., Schaman C., Kuzmany H., Calvaresi M., Zerbetto F., Meyer J. Electronic Structure of Carbon Nanotubes with Ultrahigh Curvature. ACS Nano. 2010. V.4. N.8. P.4515-4522.

[6] Kharlamova M.V., Kramberger C., Saito T., Sato Y., Suenaga K., Pichler T., Shiozawa H. Chirality-dependent growth of single-wall carbon nanotubes as revealed inside nano-test tubes. Nanoscale. 2017. V.9. N.23. P.7998-8006.

  • Open access
  • 11 Reads
Metals inside single-walled carbon nanotubes

Metals are filled inside single-walled carbon nanotubes (SWCNTs) using solution methods. They include multi-stage cleaning steps, sorting from excess salts. I filled SWCNTs with silver, copper and I investigated the clean samples after decomposition of salts to metals with Raman spectroscopy, optical absorption spectroscopy (OAS), and photoemission spectroscopy. The investigations showed that the silver and copper fillings are succsessful, this is proven by transmission electron microscopy, and other methods. The n-doping with strong modifications of spectra is observed. Metal filling is very promising for thermoelectric power generation, and copper filling was firstly made in Russia, and it was published by me in Russian journal [1,2]. This is important for approbation, and prove of results. Applications of metal filled carbon nanotubes are only possible with clean samples, and the synthesis processes of metal filled SWCNTs should be refined to obtain maximal filling ratios. The filling ratios with metal are high, and everybody can detect filling with modern techniques, Raman spectroscopy, near edge X-ray photoelectron spectroscopy, OAS, PE for applications.

[1] Kharlamova M.V., Niu J.J. Donor doping of single-walled carbon nanotubes by filling of channels with silver. Journal of Experimental and Theoretical Physics. 2012. V.115. N.3. P.485-491.

[2] Kharlamova M.V., Niu J.J. New method of the directional modification of the electronic structure of single-walled carbon nanotubes by filling channels with metallic copper from a liquid phase. JETP Letters. 2012. V.95. N.6. P.314-319.

  • Open access
  • 14 Reads
Annealing gas driven preparation of mesoporous bicrystalline N-doped TiO2 nanomaterials for sustainable sunlight degradation activity

In our study, N-doped titanium dioxide (N-TiO2) nanomaterials were successfully prepared using titanium butoxide and guanidinium chloride by simple sol-gel method. The significance of annealing gas environment (air, argon, and nitrogen) on their physicochemical properties and photocatalytic degradation against rhodamine B (RhB) under direct sunlight irradiation was investigated. The XRD and Raman data revealed that the crystal structure of N-TiO2 nanoparticles was changed from monophase anatase with less crystallinity in argon, and nitrogen to dual-phase anatase/rutile with higher crystallinity in the air. Moreover, DRS and PL results revealed that the introduction of N in the TiO2 matrix not only led to a red shift towards visible light but also narrowed the band gap (2.35 eV) and suppressed charge carries recombination unlike unmodified material. The BET showed a typical IV isotherm of mesoporous N-TiO2 materials with high specific surface area in the rage of 80-103 m2 g-1. Furthermore, their RhB photodegradation performance was dictated by the annealing gas type; nobly, the N-TiO2 prepared in air demonstrated the highest degradation performance (99%) with the highest apparent rate constant (0.0158 min-1) which is twice faster than the undoped TiO2. Such improved performance is mainly attributed to its higher crystallinity, mixed phase, aqueous-dispersion character, and lower recombination rate.

  • Open access
  • 12 Reads
Characterising Hydroxyapatite Deposited from Solution onto Novel Substrates in Terms of Growth Mechanism and Physical Chemical Properties

Bulk titanium is the most common metal for orthopaedic implants but there are some concerns surrounding it’s use. Research in the last decade has focussed on alternatives to titanium alloys, however these materials are hindered by the adhesion of a hydroxyapatite layer to non-bulk Titanium parts. Demonstrated in this work is the ability to grow hydroxyapatite on surfaces other than bulk metallic parts through process and characterisation of coating properties.

Hydroxyapatite is grown from saturated solution precursors onto thin titanium films and silicon substrates and its efficacy is proven to be dependent on substrate roughness measured at AFM. The mechanism of the hydroxyapatite growth is investigated in terms of initial attachment and morphological development through SEM analysis. Bulk titanium parts are coated in the same manner as means of comparison. Characterisation of hydroxyapatite layers by XRD demonstrate how the hydroxyapatite forms from amorphous phases to preferential crystal growth along the [002] direction and TEM imagery confirms specific d spacings. SEM-EDX and FTIR data shows adherence to known HA phases through elemental atomic weight percentages and bond assignment. All data is collated and review through the lens of different substrates whereby it is proven that once hydroxyapatite seeds it grows identically regardless of substrate.