Synthesis and Characterization of Cellulose Acetate Membranes with Self-Indicating Properties by Changing the Membrane Surface Color for Separation of Gd(III)

This study presents a new, revolutionary, and easy method for evaluating the separation process through a membrane that is based on changing the color of the membrane surface during the separation process. For this purpose, a cellulose acetate membrane surface was modified in several steps: initially with amino propyl triethoxysilane, followed by glutaraldehyde reaction and calmagite immobilization. Calmagite was chosen for its dual role as a molecule that will complex and retain Gd(III) and also as an indicator for Gd(III). At the contact with the membrane surface, calmagite will actively complex and retain Gd(III), and it will change the color of the membrane surface during the complexation process, showing that the separation occurred. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA-DTA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, demonstrating the synthesis of membrane material with self-indicating properties. In addition, in the separation of the Gd(III) process, in which a solution of gadolinium nitrate was used as a source and as a moderator in nuclear reactors, the membrane changed its color from blue to pink. The membrane performances were tested by Induced Coupled Plasma–Mass Spectrometry (ICP-MS) analyses showing a separation process efficiency of 86% relative to the initial feed solution.

Study Of Cobalt Doped Gdalo3 For Electrochemical Application

BACKGROUND: Nano perovskite-type structure as denoted by ABO3 (A= RE) have been popular targets of fundamental investigations since they exhibit a wide variety of physical properties depending upon the chemical composition, defects and small changes in atomic arrangements. METHODS: GdAlO3:Co2+ (1, 3 &9 mol %) synthesized using the solution combustion method by using stoichiometric quantities of gadolinium nitrate [Gd (NO3)3], aluminium nitrate (Al (NO3)2, cobalt nitrate Co(NO3)2. RESULTS: The morphology, structure and particle size of the prepared GdAlO3:Co2+ sample characterized by transmission electron microscope (TEM) image. The Fourier transform infrared (FTIR) spectral analysis confirms that the as-prepared powder itself is in pure phase. Electrochemical impedance measurements (EIS) of different GdAlO3: Co2+ samples were measured vs Ag/AgCl in the frequency range of 1 Hz to 1 MHz with AC amplitude of 5 mV at steady-state which clearly indicates that Co2+ dopant was successful doping material for the fabrication of supercapacitors. CONCLUSION: Electrochemical impedance measurements (EIS) of different GdAlO3: Co2+ samples were measured vs Ag/AgCl in the frequency range of 1 Hz to 1 MHz with AC amplitude of 5 mV at steady-state which clearly indicates that Co2+ dopant was successful doping material for the fabrication of supercapacitors. As a future perspective, we believe that GdAlO3:Co2+ composite material could be a promising electrode material for the fabrication of various sensors, supercapacitors and solar cells.

A Study and Comparison of the Preparation of Gadolinium Aluminate Nanoparticles Using γ-Irradiated and Unirradiated Precursors

The effects of γ-irradiation and the application of different precursors on the formation of gadolinium aluminate (GdAlO3) nanoparticles (NPs) have been studied in detail. GdAlO3 NPs were prepared by using different gadolinium-based precursors including gadolinium acetate (Gd(CH3COO)3·4H2O) and gadolinium nitrate (Gd(NO3)3·6H2O), while Al2O3 and Al(NO3)3·9H2O were used as the source of Al3+. The preparation of GdAlO3 was carried out by two different methods, solid-state reaction and sol-gel process. To study the effect of γ-irradiation, both irradiated and unirradiated Gd(CH3COO)3·4H2O have been tested for the preparation of gadolinium aluminate (GdAlO3). Notably, Gd(CH3COO)3·4H2O did not produce GdAlO3 in both solid-state and sol-gel processes even after optimizing various parameters, including the application of γ-irradiation. However, single-phase nanocrystalline GdAlO3 NPs were successfully obtained from the reaction of gadolinium nitrate Gd(NO3)3·6H2O and Al(NO3)3·9H2O by a sol-gel process. The formation of NPs has been confirmed by X-ray diffraction analysis (XRD) and Fourier-transform infrared (FT-IR) spectroscopy. The results indicate towards the formation of an orthorhombic perovskite structure of GdAO3 in the Pbnm space group. Transmission electron microscopy (TEM) has been employed for the particle-size analysis, which revealed the formation of spherical-shaped nanoparticles with the size range of 50–70 nm. Surface morphology of the sintered pellet was obtained from high-resolution scanning electron microscopy (HR-SEM). Besides, the effect of irradiation with γ-rays on the quality of resultant NPs has also been studied.

EXTRACTION OF RARE-EARTH ELEMENTS BY MIXES OF ISOMERS OF TRIBUTYLPHOSPHATE WITH NITRATE TRIALKYLMETHYLAMMONIUM

Results of studying of extraction of nitrates of rare-earth elements (REE) and trialkylmetylammoniya nitrate (TAMAN) are given by mixes of isomers of tributyl phosphate (TBP). Tri-iso-butylphosphate and tri - sec-butylphosphate are investigated as isomers of normal tributylphosphate. The water phase contained 8 mol/dm3 nitrate of ammonium and 5.10-4 mol/dm3 of neodymium nitrate at рН = 2-3. The content of extractants in isomolar series was varied in the range of 0-0.3 mol/dm3. It was established that synergistic effect decreases in a series of TBP> TIBP> TvtBP. Synergistic effect is calculated as the distribution coefficient relation at extraction by mix of extractants to the sum of coefficients of distribution at extraction by each of extractants. Synergistic effect reaches its maximum value at the ratio: [NPOC] : [TAMAN] = 2 : 1 for TBP and 4-5 : 1 for TiBP, TvtBP, and the absolute value fluctuates within 10-50 at extraction of microconcentration of REE. It is noted that the method of isomolar series is applied incorrectly in many researches with the violation of the fundamental requirements (variable concentration of rare earth metals and acid in the aqueous phase, an assumption of a possibility of simultaneous existence of several solvate, variable concentration of salting-out owing to extraction into the organic phase, the association and polymerization in the organic phase, etc..), which must be followed when using this method. Мultiple saturation method (MSM) is offered for a correct application of the method of isomolar series. The method consists in the fact that the organic phase is saturated repeatedly (5-6 times) with the original aqueous solution until a constant composition of the aqueous phase at all points of isomolar series. It is possible to believe that the organic phase is responsible for the deviation from the additivity in this case. It was established that synergistic effect tends to unity or virtually disappears in the extraction of REE macroamounts method of ofisomolar series of multiple saturation. It is shown that value of synergistic effect approaches unity at gadolinium nitrate extraction by isomolar mix in the MSM mode. Synergistic effect for a mixture of rare earth elements is close to unity in the extraction of REE mixtures macroamounts of TiBP and TAMAN, and the individual elements are distributed in accordance with the extraction characteristics of each of the extractants alone: synergistic effect for several elements of cerium is greater than one, and yttrium - somewhat less than one. It is suggested that if there is free extragent the formation of mixed solvate may be explained by the steric effect, which disappears at saturation of extracgent.Forcitation:Val'kov A.V., Khmelevskaya N.D. Extraction of rare-earth elements by mixes of isomers of tributylphosphate with nitrate trialkylmethylammonium. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 54-60

A Study on Biocompatibility of Gadolinium Based Anodizing Coating AZ91D Magnesium Alloy in Simulated Body Fluid (SBF) Solution

Pure Mg and AZ91D alloy was anodized with and without the gadolinium nitrate Gd (NO3)3 in different concentrations (0.001g/l, 0.025g/l, 0.05g/l, 0.075g/l and 0.09g/l) at a constant current density and treatment time of 10mA/cm2 and 5 minutes. The results showed that the optimum gadolinium concentration is 0.075g/l due to obtaining the anodic film with high corrosion resistance. The surface morphology and microstructure of anodic coating were investigated by scanning electron microscopy (SEM) , optical microscope (OM), and potentiodynamic polarization, respectively.