Extraction behavior of Am(III) and Eu(III) by tri-n-octylmethylammonium diglycolamate ionic liquid impregnated XAD-7

Aliquat-336-based strongly hydrophobic ionic liquid, tri-n-octylmethylammonium diglycolamate ([A336]⁺[DGA]^?), was prepared and impregnated in Amberlite XAD-7 (abbreviated as [A336]⁺[DGA]^?/XAD-7) for studying the extraction behavior of Am(III) and Eu(III) from nitric acid medium. The distribution ratio of Am(III) and Eu(III) in [A336]⁺[DGA]^?/XAD-7 decreased with an increase in the concentration of nitric acid and the mechanism of trivalent metal ion extraction in the resin phase was elucidated. The uptake of Am(III) and Eu(III) in [A336]⁺[DGA]^?/XAD-7 followed a second order and from the Langmuir adsorption model the apparent europium extraction capacity was determined. The conditions needed for efficient separation of Am(III) from Eu(III) was optimized.     

Electrodeposition of aluminium and aluminium-copper alloys from a room temperature ionic liquid electrolyte containing aluminium chlo- ride and triethylamine hydrochloride

The electrodeposition of A1 and A1-Cu binary alloys on to gold substrates from a room temperature ionic liquid electrolyte containing A1C13-EtaNHC1 was studied. The electrochemical behavior of the electrolyte and the mechanism of deposition were investigated through cyclic voltammetry （CV）, and the properties of deposits obtained were assessed by scanning electron microscopy with energy dispersive X-ray spectroscopy （SEM-EDS） and X-ray diffraction （XRD）. A1 of 70μm in thickness and an A1-Cu alloy of 30μm in thickness with 8at% copper were deposited from the electrolyte. SEM images of the deposits indicate that the A1 deposit was smooth and uniform, whereas the Al-Cu deposit was nodular. The average crystalline size, as determined by XRD patterns, was found to be （30±5） and （29±5） nm, respectively, for A1 and A1-Cu alloys. Potentiodynamic polarization （Tafel plots） and electrochemical impedance spectroscopic （EIS） measurements showed that Al-Cu alloys are more corrosion resistant than Al.     

Novel Diglycolamic Acid Functionalized Iron Oxide Particles for the Mutual Separation of Eu(III) and Am(III)

Iron oxide (Fe₃O₄) particles functionalized with diglycolamic acid (Fe-DGAH) were synthesized and characterized by TG-DTA, X-Ray diffraction,¹H NMR, and scanning electron microscopy (SEM). The extraction behavior of Am(III) and Eu(III) in Fe-DGAH was studied from dilute nitric acid medium to examine the feasibility for the mutual separation of trivalent actinides and lanthanides using Fe-DGAH. For this purpose, the effect of various parameters such as the duration of equilibration and concentrations of europium, nitric acid, and diethylenetriaminepentaacetic acid (DTPA) in the aqueous phase on the distribution ratio (K_d) of Am(III) and Eu(III) was studied. The conditions needed for the efficient separation of Am(III) from Eu(III) were optimized using DTPA. The distribution ratio of ?10⁴ mL/g was obtained for both Am(III) and Eu(III) at pH 3, and it decreased with an increase in the concentration of nitric acid. However, a separation factor of Eu(III) over Am(III) of ?150 was achieved in the presence of DTPA. Rapid sorption of metal ions in the initial stages of equilibration followed by the establishment of equilibrium occurred within 2 h. The sorption data were fitted to the Langmuir adsorption model, and the apparent europium sorption capacity was determined to be ?50 mg/g. The study indicated the feasibility of using Fe-DGAH particles for magnetic separation of Eu(III) from Am(III) with high separation factors.     

Extraction Behavior of Some Actinides and Fission Products from Nitric Acid Medium by a New Unsymmetrical Diglycolamide

Abstract

A new unsymmetrical diglycolamide, N,N-di-2-ethylhexyl-N',N'-di-octyl-3-oxapentane-1,5-diamide, trivially known as di-ethylhexyl-di-octyl-diglycolamide (DEHDODGA) has been synthesized, and characterized by ¹H, and ¹³C nmr, mass, and IR spectroscopy. Extraction behavior of ²⁴¹Am(III), ^(152+154)Eu(III), ²³⁹Pu(III), ²³⁹Pu(IV), ²³³U(VI), ¹³⁷Cs(I), and ^(85+89)Sr(II) from nitric acid medium by a solution of DEHDODGA in n-dodecane was studied, at 298–333 K. The effect of concentrations of HNO₃ and DEHDODGA and of temperature on the distribution ratio (D _M) was studied. Extraction of Eu(III), Am(III), Pu(III), and Pu(IV) increased with increase in nitric acid concentration, and the distribution ratio of Cs(I) was insignificant. However, the distribution ratios of U(VI) and Sr(II), though not insignificant, but was quite less compared to trivalents, and Pu(IV). The D _Sr(II) increased with increase in the concentration of nitric acid, reaching a maximum at 4 M followed by decrease. The stoichiometry of Am(III) – DEHDODGA was determined by slope analysis of extraction data, and the enthalpy change accompanied by the extraction of Eu(III), Pu(III), and Am(III) was determined and reported in this article.     

Comprehensive studies on processing and characterization of hybrid magnesium composites

The need for cost-effective energy-efficient materials that can accommodate the diverse industrial demands has stimulated the advancement of magnesium-based materials. One such recently-reported advancement is magnesium-based hybrid composites in which more than one reinforcement phase is added to the base matrix. Hybrid composites offer wide flexibility in terms of the selection of reinforcing phases as well as in terms of the processing routes. Thus, these composites have potential applications in aerospace and automotive sectors. Magnesium-based hybrid composites also exhibit superior mechanical and tribological properties over their lightweight counterparts. Based on the available literature, this paper attempts to review current developments associated with magnesium-based hybrid composites in terms of processing techniques, metallurgical characteristics, and mechanical properties.     

Thermal performance analysis of silica tiles

The thermal response of nonablating ceramic tiles is studied by the finite-element method. A continuum model is used to determine the thermal conductivity of porous materials. The temperature distribution for the one-dimensional model is compared with the available arc-jet result. Also presented are the 2D and 3D temperature contours and the heat-flux distributions for silica tiles. The expression for the pressure distribution in a silica tile is derived. Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 6, pp. 107–113, November–December, 2006.     

Behaviour of micro-and nano-alumina-reinforced Mg-3Zn-0.7Zr-1Cu alloy composites processed at different sintering temperatures

This study aims to develop a magnesium-based hybrid composite via a powder metallurgy(PM)technique by simultaneously reinforcing the matrix(Mg-3Zn-0.7Zr-lCu)all...     

Gold nanoparticles decorated reduced graphene oxide nanolabel for voltammetric immunosensing

This study describes the development and testing of a simple and novel enzyme‐free nanolabel for the detection and signal amplification in a sandwich immunoassay. Gold nanoparticles decorated reduced graphene oxide (rGOAu) was used as the nanolabel for the quantitative detection of human immunoglobulin G (HIgG). The rGOAu nanolabel was synthesised by one pot chemical reduction of graphene oxide and chloroauric acid using sodium borohydride. The pseudo‐peroxidase behaviour of rGOAu makes the nanolabel unique from other existing labels. The immunosensing platform was fabricated using self‐assembled monolayers of 11‐mercaptoundecanoic acid (11‐MUDA) on a gold disc electrode. The covalent immobilisation of antibody was achieved through the bonding of the carboxyl group of 11‐MUDA and the amino group of the antibody using chemical linkers [1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide] and N ‐hydroxysuccinimide. The fabricated immunosensor exhibited a linear range that included HIgG concentrations of 62.5–500 ng ml⁻¹. The sensor was also used for the testing of HIgG in the blood sample.Inspec keywords: proteins, nanomedicine, reduction (chemical), chemical sensors, nanofabrication, electrochemical sensors, voltammetry (chemical analysis), gold, oxidation, self‐assembly, monolayers, molecular biophysics, biochemistry, biosensors, nanoparticles, nanosensors, blood, grapheneOther keywords: gold nanoparticles, voltammetric immunosensing, enzyme‐free nanolabel, signal amplification, sandwich immunoassay, human immunoglobulin G, rGOAu nanolabel, chloroauric acid, sodium borohydride, 11‐mercaptoundecanoic acid, 11‐MUDA, gold disc electrode, chemical linkers, 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide], HIgG concentrations, reduced graphene oxide nanolabel, quantitative HIgG detection, one pot chemical reduction, covalent antibody immobilisation, carboxyl group bonding, pseudo‐peroxidase behaviour, self‐assembled monolayers, N‐hydroxysuccinimide, immunosensor, blood sample, Au‐CO