Luiz Gustavo Barbosa, Glaucia Karina Martofel, Creusa Iara Ferreira, Raquel Santos Mauler

This article presents a brief review of some methods of obtaining graphite and graphene nanosheets, the latter a material that has attracted much attention from the scientific community in recent years, due to its different properties and possible applications. Next, the work addresses the subject of graphite exfoliation by the sonication method, which is simple and versatile, and by which it is possible to obtain graphite sheets with thicknesses of units of nanometers. Furthermore, the work presents experimental data that show the influence of the sonication time interval on the dimensions of graphite nanosheets. The results indicate that longer the sonication time interval, smaller the dimensions of the graphite sheets.

Yande Diouf, Saïdou Diallo, Kharouna Talla, Louis Gomis

The work we present here is intended as a contribution to the study of the thermodynamic properties of zircon. For this purpose, we have implemented the quasi-harmonic Debye model, in which the vibrations of the network of atoms are taken into account. This study has a dual objective, first to calculate the thermodynamic quantities of zircon for different temperatures and to test the validity of the model with the data available in the literature. In addition, due to the structural complexity of the zircon equation of state, we have developed a Matlab code in deterministic mode to perform the calculations. At the end of the study, the results obtained are consistent and meaningful. Overall, the results indicate that heat capacity, internal energy and entropy increase with temperature. This growth is more marked with the internal energy than with the entropy and the thermal capacity which tends towards the limit value of Dulong-Petit. In addition, the results of our simulations are in excellent agreement with others reported in the literature. These studies clearly demonstrate that zircon can be categorized as hard materials due to their high Debye temperature. We hope that this study could stimulate experimental studies about zircon (ZrSiO4) characterization in Senegal.

Rasha Said Shams Eldine, Ibrahim Y. Ibrahim

Despite the wide application of nanoparticles (NPs), there is a serious lack of information concerning their impact on human health and the environment. In fact, nano-materials are the leading edge of nanotechnology and their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. Zinc oxide nanoparticles were produced synthetically by wet chemical route by using cheap precursors. The size of the particles were determined by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) and was compared to that of bulk ZnO. structure and size Further studies were carried out to determine the difference in electrical properties (dielectric constant, dissipation factor, A.C. conductivity, resistivity) of these materials due to their size difference. Similar variations occurred in the liver enzymes; ALT, AST, as a result of treated the rats with ZnO in the bulk and Nano-forms. The increase in these enzymes indicated liver damage toxicity.

Misael Silas Nadiye-Tabbiruka, Fortunate Phenyo Sejie

Coal/clay nano composites of ratios 1:1, 1:4, 4:1 were successfully prepared and characterised by electron microscopy. They were then used to study kinetics and thermodynamics of removal from water of methyl orange of various concentrations, various pH and at various temperatures. The coal:clay ratios 1:1 and 4:1 performed equally but better than 1:4 and the individual coal and clay samples. The swelling in coal and in clay which occurs on initial adsorption appears to have been eliminated by the miniaturisation. The adsorption capacity of the composites was found to be higher than that of either the clay or the coal on their own but it is still lower than that of commercial activated carbon.

Droepenu Eric Kwabena, Asare Ebenezer Aquisman

Green synthesis of nanoparticles by plant extracts is gaining grounds in the field of nanotechnology. ZnO Nanoparticles (NPs) were successfully synthesized in this study using two different aqueous extract (fresh leaf and fresh stem bark) from Carica papaya on the same precursor and alkaline source (Zinc acetate dihydrate and Potassium hydroxide respectively) in a method by Moazzen et al., 2012 with some modifications. Ultraviolet–Visible spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FT-IR), Energy-Dispersive X-ray analysis (EDX), Transmission Electron Microscope (TEM) and Scanning Electron Microscopy (SEM) were adopted as characterization techniques for the synthesized samples. The report showed that, fabrication of ZnO NPs from the extracts were successful with thin organic materials surrounding the agglomerated particles. The absorption band and wavelength observed at 444 cm^-1 and 213.9 nm from the FT-IR and AAS respectively indicates the presence of ZnO in the synthesized samples. UV-Vis spectroscopy further confirmed a strong optical property of the ZnO NPs with a strong absorption peaks at around 365 and 370 nm wavelength. The synthesized samples are made up of flower-like or petal-like shapes with average particle size range of 141-168 nm with width 40 nm and length 89 nm.

Tenderwealth Clement Jackson, Bernard Opatimidi Patani, Nonye Linda Ifekpolugo, Edidiong Michael Udofa, Nkem Mercy Obiakor

Development of Metronidazole loaded silver nanoparticles from Acalypha ciliata was carried out using the juice from the leaves of Acalypha ciliata as reducing agent and modified starch as stabilizing agent. Nanoparticles synthesized were labelled as nanometA, nanometB and nanometC. The percentage yield of the nanoparticles were above 88%. The entrapment efficiencies were 78.60%, 84.92% and 87.19% while the loading capacities were 26.18%, 12.10% and 7.92% for nanometA, nanometB and nanometC respectively. Differential scanning calorimetry (DSC) for optimized batch indicated the absence of interaction between the starch and drug. The UV VIS spectroscopy showed Surface Plasmon resonance of 407 nm for optimized batch while the mean particle size was 425.7 nm. All the batches showed controlled release of the drug from the Nanoparticles. The kinetics of release was mainly zero order for all the nanoparticles. Antimicrobial property of the optimized nanoparticle was significantly (P< 0.01) higher with increasing polymer to drug ratio.

Md. Sayedul Islam, Md. Wahab Khan

Triazine-based dendrimer assisted Pd-Cu bimetallic nanoparticles (NPs) were synthesized through the sequential loading method from the dendrimer which was prepared by the reaction of 2,4,6-triamino-1,3,5-triazine with benzoyl chloride in DMF at 80°C at 8 hrs. The dendrimer was characterized by IR, NMR, and elemental analysis. SEM and EDX of Pd-Cu bimetallic NPs demonstrated nanosized spherical surface morphology as well as the existence of palladium ions, and copper ions in the nanoparticles whereas TGA and DSC confirmed good thermal stability of the nanoparticles, in addition, XRD data and the analysis of TEM revealed the average 18.50 nm nano shape FCC structure of the particles. These NPs were found to be the effective heterogeneous a catalyst for the C-C cross-coupling reactions such as Heck, Sonogashira in excellent yields. The high stability, reusability, and heterogeneity of recovered catalyst was also observed by further analysis (SEM, EDX, XRD, TEM and leaching study).

Marina Rodio, Romuald Intartaglia

Ceramic nanoparticles are promising biomaterials for bone tissue regeneration, cell proliferation and as plasmid DNA delivery vector, because they bear outstanding properties of chemical similarity to the human mineral constituent, bioactivity, and are fairly easily bio-conjugated. Here we report on the synthesis of hydroxyapatite nanoparticles by laser ablation of hydroxyapatite target in deionized water and in aqueous solution of Serum Albumin protein. Laser ablation in deionized water results in the formation of large clusters composed by small nanoparticles, while in Serum Albumin protein solution a starting process of clusters disaggregation is observed. Stability and nanoparticle size-quenching effect is investigated by various methods such as electron microscopy zeta potential and dynamic light scattering. It is found that the presence of Serum Albumin protein in aqueous solution plays the role of size-regulating agent. The integrity of Serum Albumin protein after laser irradiation is assessed by means of UV-vis and FT- IR analysis. Further, the chemical structure and crystallinity of the hydroxyapatite colloidal solution is investigated by infrared spectroscopy, X-Ray diffraction measurement and energy-dispersive X-ray diffraction.

Santos-Adriana Martel-Estrada

Carbon based nanomaterials have unique advantages in several areas due to its electronic, optical, thermal, and mechanical properties. In these terms, nanodiamonds have attracted considerable attention in recent years in different research areas such as biological sensing, medical therapy, fluorescent markers, enzyme immobilization and so on. Nanodiamond (ND) is a new member of carbon nanoparticle family with a truncated octahedral architecture that showed superior characteristics of diamond. This review is focus on synthesis methods, dispersion, functionalization, medical applications and toxicity of nanodiamonds.

V. K. Srivastava

Solid-vapor reaction process (SVRP) method is used to synthesize the silicon carbide (SiC) nanofibers with the variation of temperature 550-650°C respectively. Synthesize samples are heated at 700°C for 2 hours to burn out the carbon residues. The synthesize SiC nanofibers consist of SiC-SiC with longer length than that of the mother carbon nanofibers. The microstructure of the synthesize sample is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the carbon nanofibers are fully converted into the silicon carbide nanofibers uniformly.