فصلنامه دنیای نانو
پیاپی 55 (تابستان 1398)

Magnetic polyethylene oxide synthesized in the presence of an external magnetic field by co-precipitation method and the effect of the magnetic field was investigated. The synthesized nanocomposite was characterized by SEM, XRD and VSM Analyses. VSM result shows that the magnetic saturation was increased to 70 emu/g in the presence of magnetic field and this value was closed to the iron oxide nanoparticles magnetic saturation and confirms the fabrication of nanocomposite with a high magnetic feature. Furthermore, to the reason of high magnetic feature of the nanocomposite, nanoparticles are aggregated in SEM image. The significate features of this study were using low-cost and available material, easy synthesize process and preparing nanocomposites with notable magnetic feature.]]>

The separation of nitrate ions, due to its high solubility, is difficult and costly into conventional methods in water treatment. The purpose of this study is to calculate the efficiency of nano ghrefen oxide NGO in removal and reduction of nitrate ions in aqueous media. Nano-graphene oxide NGO has some factor groups such as: double bond of SP2, carboxy, hydroxy and proxy. The thermodynamic and electrical parameters are calculated for approaching of nitrate ions to the carboxy, hydroxy and proxy group by B3LYP/6-31 G method. The proxy group is greatest probability, the gap between the HOMO and LUMO energy levels is the lowest value in this case, is indicating high electron transfer and high conductivity between pollutant and nano-ghrefen oxide. Therefore, The thermodynamic and electrical parameters are calculated and evaluated for the conversion and reduction mechanism of nitrate on this group, the results showed that the proposed reaction is the spontaneous and exothermic. Therefore, the nano-graphene oxide can be used to identify, remove and reduce nitrate ions in aqueous media.]]>

<![CDATA[Among different separation methods for water treatment and desalination, membrane separation attracted attention of scientific research and technology because of high performance, decrease of energy usage and costs. Graphene base materials are two dimensional carbon nanosheets which can use in different processes such as membrane separation. They are good candidate for substitution of conventional polyamide membrane with low water flux. Graphene oxide GO with oxygen containing functional groups as hydrophilic derived of graphene has superior intrinsic propriety in transporting water molecule. The presence of functional groups creates nanochannel between GO nanosheets for water transport across the GO membrane. Additionally presence of these functional groups makes possible structural modification of GO to improve mechanical properties and separation performance. Improving stability of the membrane, manufacturing method and commercialization are the most important challenges of the GO membranes. Easy of manufacturing, high water flux compare to conventional polyamide membranes, less fouling and high chlorine resistance stability has led to bright future of GO membrane.]]>

<![CDATA[The aim of this study is to investigate the specific properties, novel synthetic methods and industrial -biomedical applications of Titanium nanoparticles. The present study is a review of the results of valid indexed publications and theses by 2019. The current methods to synthesis Titanium nanoparticles are hydrothermal and sol-gel. Recently, the combinatorial assays such as sol-gel-electrophoresis and sol-gel-mill and biological or green synthesis of nanoparticles by plants have been more considered. The specific properties of these nanoparticles, such as high resistance to temperature and pressure, self-cleaning, antimicrobial, non-toxic and high tend to proteins and cells have led to the use of them to make implants, industry, tissue engineering, and detection and treatment of diseases. The applications of this nanoparticle require more practical research in human to replace it with many toxic and expensive chemical compounds.]]>

<![CDATA[By fabricating a copper nano-fiber mesh, a high quality, low cost, and flexible transparent electrode can be produced. The transparent electrodes are widely used in electro-optic devices such as screens, touch screens and solar cells. The metallic nano-fiber mesh is superior to ITO in terms of flexibility and low cost raw material, and superior to graphene or carbon nanotubes in terms of low junction resistance by high aspect ratio. The copper is much cheaper than gold and silver while has a very good conductivity. But the main problem is oxidation of nano-layer in sputtering process. Basically, expensive methods such as high vacuum deposition can prevent the oxidation. But in this study, with the use of the active atmosphere and the addition of hydrogen to argon gas in a sputtering chamber, the purity of sputtered copper is much better, so that its conductivity is improved up to 5 times.]]>

Nano-scale gas filled cavities, suspended in the bulk of a solution or located on a liquid/solid interface have been known as bulk and surface nanobubbles NBs, respectively. The existence of NBs was argued by the researcher for a long time. However, with the advent of different microscopic techniques, capable for detecting nanoscale features the nanoscale-gas filled cavities were confirmed. Recently, NBs exhibiting outstanding and unique properties such as extraordinary stability, possessing negative surface charges and reactive oxygen species ROS generation draw a great deal of attention in different fields such as water industry, agriculture and biomedicine. In general, there are three main techniques to produce NBs including spontaneous generation, gas supersaturation and finally induced-shaking and pressure fluctuations in liquids. This review paper, introduces a brief deion and classification of NBs, a discussion on main properties of NBs such as giving evidence for and against different aspects and theories of long stability and ultimately, the main generation techniques and industrial applications. ]]>

<![CDATA[Progress in nanotechnology cause to use nanoparticles in preparing the nano catalysts. Nanoscale catalysts has provided excellent conditions for catalysis science.Nanocatalyst research has always been one of the most engaging and popular discussions in nanoscience and attracted the attention of many scholars.
In this research, along with the introduction of ferrite nanocrystals and their synthesis methods, the catalytic activity of these materials is also investigated.
application and nanocrystals catalistic properties were investigated by UV- visble spectroscopy. ]]>