Search

Nanostructure titanium carbide MXene (Ti3C2Tx) was modified with KH2PO4 and chitosan to effectively remove strontium from nuclear wastewater. Nuclear waste includes radionuclides of uranium, thorium, strontium, and cesium, which are classified depending on the concentration of radionuclides. Nuclear waste with a high strontium concentration is the production waste of radiopharmaceutical production centers. Ti3C2Tx was synthesized from Ti3AlC2 using HF40% and HF in situ (MILD-Ti3C2Tx) in 24 h at 313.15 and 333.15 K. Morphology, structure, and functional groups were investigated using the XRD, SEM, EDS, FTIR, and BET analyses. The Sr(II)'s adsorption capacity on Ti3C2Tx-HF and Ti3C2Tx-HF in situ was obtained as 61.9 and 253.5 mg g−1, respectively (temperature, 298.15 K; pH, 7.00; contact time, 180 min; and Sr(II) concentration, 150 mg l−1). Ti3C2Tx-HF in situ showed fourfold adsorption due to more hydroxyl functional groups and larger interlayer spacing. Ti3C2Tx was modified with KH2PO4 and chitosan to investigate the mechanism of change of Sr(II)'s adsorption capacity, which increased to 370 and 284 mg g−1, respectively. The structural results of modified Ti3C2Tx showed that the surface functional groups increased when modified with chitosan. In addition, modification with KH2PO4, through encapsulating large amounts of KH2PO4 between Ti3C2Tx layers, increased the possibility of Sr(II) diffusion between layers and electrochemical interactions with hydroxyl groups, and thus, increased its adsorption. Some experiments were designed to investigate the effect of parameters like initial concentration of Sr(II), contact time, temperature, and pH solution, as well as modified- and unmodified-Ti3C2Tx on adsorbent. The results revealed that the adsorption process of Sr(II) with pristine and modified-Ti3C2Tx follows pseudo-second-order kinetics and Freundlich heterogeneous isotherm model. Freundlich model isotherm indicates the presence of various functional groups on the surface and between the pristine and modified Ti3C2Tx layers. Electrostatic reactions and intra-sphere complexation were the two dominant mechanisms of the adsorption process. [ABSTRACT FROM AUTHOR]

To carry out our research, C6CoFeN6@poly-1-naphthol nanoparticles were synthesized and characterized by SEM, X-ray diffraction, Fourier transform infrared, thermogravimetric analysis and Brunauer-Emmett-Teller (BET) analyses. The SEM images indicate that the average particle sizes are about 60 nm in diameter. The BET result provides a clear evidence for the high surface area of the sample 180.6 m2/g. Cs(I) ions removed from the aqueous solution in a batch mode using CoHCF@poly-1-nanphtol as an adsorbent. The adsorption effecting parameters such as the solution pH, initial Cs(I) concentration, contact time and temperature were studied. Maximum sorption capacity for the nanocomposite was found to be 200.5 mg/g at 1000 mg/g, pH = 5 and 298 K. The time-adsorption dependence studies indicated that the maximum Cs(I) uptake was within the initial 40 min contact time and the adsorption mechanism was governed by the double exponential model. The equilibrium sorption data fitted well to the Freudlich model with n ˃ 1 indicating a stronger interaction and high affinity of C6CoFeN6@poly-1-naphthol for Cs(I) ions. The thermodynamic parameters, including changes in Gibbs free energy, entropy and enthalpy, were determined. The results indicated that CoHCF-poly-1-nanphtol could be a potential adsorbent for the uptake of Cs(I) ions from an aqueous solution. [ABSTRACT FROM AUTHOR]

The aim of this research was to introduce a new, facile and simple method for synthesis of DyO nanostructures at room temperature. For the first time, galvanostatic electrodeposition was used to synthesize DyO particles, and the influence of the current density on the structure and morphology of the product was studied. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). The results show that the current density has little effect on the chemical composition but great effect on the structure and morphology of the samples. The average size of the particles decreases as the applied current density increases. The grain size of as-prepared samples decreases from 500 to 70 nm when the current density increases from 0.5 to 6.0 mA·cm. To obtain oxide product, the as-prepared samples were heat-treated at 1,000 °C. The results show that the heat-treated samples have smaller particles. The XRD results show that the similar patterns are observed in the samples synthesized at different current densities, and the only difference from the JCPDS card is the ratio of peak intensities. With the increase in the current density, a decrease in the current efficiency is observed. [ABSTRACT FROM AUTHOR]

A new FeIIISnIISnIVH[P(MoO)]· xHO nano-hybrid was synthesized by chemical co-precipitation. The product was characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. From TEM images, the size of the product was estimated to be smaller than 30 nm. The adsorption efficiency of the obtained hybrids were determined for Sr(II) and Th(IV) ions. The kinetics and thermodynamic of metal ions were studied. Results explained that the pseudo second-order sorption mechanism is predominant and the sorption of each ion is an endothermic process. [ABSTRACT FROM AUTHOR]

Three different photocatalysts including TiO, TiO/SiO and TiO/SiO/Ag were synthesized via sol-gel growth method, in which colloidal silica was used as Si source, titanium tetra iso-propoxide (TTiP) as titanium source, Ag as dopant ion and hydroxypropyl cellulose (HPC) as dispersant. The purpose was to study the enhancement of photocatalytic activity of TiO by deposition on SiO colloids and also doping with Ag ion. The catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) methods. It is confirmed that the major phase in all catalysts is anatase. Photocatalytic activity was studied in various conditions for degradation of methylorange (as a model pollutant) to evaluate the effect of some parameters on degradation efficiency. Studying the degradation process in various pH values reveals that the degradation is more efficient in acidic solution than alkaline condition. Coupling the photocatalytic process with some fields called electro-photochemical (EP), magnetic-photochemical (MP) and ultrasonic-photochemical (UP) was studied at two pH values which were compared with photochemical (P) alone. It is concluded that in most cases, the EP is the best coupled system and has the maximum efficiency. Liquid chromatography-mass spectrometry (LC-MS) analysis was used to check the complete decomposition of methylorange at the end of process. [ABSTRACT FROM AUTHOR]

GdO nanoparticles were synthesized from the commercial bulk GdO powders via a simple electrochemical method. The synthesized powders were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The effects of solution pH on the morphological features of the sample were studied. The strategy developed in this study offers significant advantages for the synthesis of GdO nanoparticles from the bulk GdO powders compared with the conventional routes. From SEM observations, the size of the GdO nanoparticles is estimated to be significantly smaller than 70 nm. [ABSTRACT FROM AUTHOR]