Radiation-induced lattice relaxation in [Formula: see text]-Fe[Formula: see text]O[Formula: see text] nanorods.

We report radiation-induced lattice relaxation of the [Formula: see text]-Fe[Formula: see text]O[Formula: see text] and its associated alteration of particle morphology. The [Formula: see text]-Fe[Formula: see text]O[Formula: see text] was grown in solution by microwave hydrothermal synthesis technique in which more than half of the synthesized material was nanorods with axis along the (001) direction. Five sets of the synthesized [Formula: see text]-Fe[Formula: see text]O[Formula: see text] samples were irradiated using gamma-ray from [Formula: see text]Co cell with doses of 600 kGy, 700 kGy, 800 kGy, 900 kGy, and 1 MGy. The investigation of the pristine and gamma-irradiated samples was carried out using X-ray powder diffraction, transmission electron microscope, and electron paramagnetic resonance methods. Results showed that continuous alternation of radiation-induced lattice compression and expansion causes lattice relaxation. The morphology of the [Formula: see text]-Fe[Formula: see text]O[Formula: see text] nanorods was found to change with absorbed dose into buckyball-shaped particles in response to the alternation of the compression and expansion strain. The EPR results showed a correlation between distortion in the [Formula: see text]-[Formula: see text] octahedron structure and the relaxation of the lattice. The synthesis, growth, and relaxation are discussed in detail.

Biosorption of uranium by immobilized Nostoc sp. and Scenedesmus sp.: kinetic and equilibrium modeling.

Different activities related to uranium mining and nuclear industry may have a negative impact on the environment. Bioremediation of nuclear pollutants using microorganisms is an effective, safe, and economic method. The present study compared the uranium biosorption efficiency of two immobilized algae: Nostoc sp. (cyanophyte) and Scenedesmus sp. (chlorophyte). Effects of metal concentration, contact time, pH, and biosorbent dosage were also studied. The maximum biosorption capacity (60%) by Nostoc sp. was obtained at 300 mg/l uranium solution, 60 min, pH 4.5, and 4.2 g/l algal dosage, whereas Scenedesmus sp. maximally absorbed uranium (65 %) at 150 mg/l uranium solution, 40 min, pH 4.5, and 5.6 g/l of algal dosage. The interaction of metal ions as Na2SO4, FeCl3, CuCl2, NiCl2, CoCl2, CdCl2, and AlCl3 did not support the uranium biosorption by algae. The obtained data was adapted to the linearized form of the Langmuir isotherm model. The experimental qmax values were 130 and 75 mg/g for Nostoc sp. and Scenedesmus sp., respectively. Moreover, the pseudo-second-order kinetic model was more applicable, as the calculated parameters were close to the experimental data. The biosorbents were also characterized by Fourier-transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) analyses. The results suggest the applicability of algae, in their immobilized form, for recovery and biosorption of uranium from aqueous solution.

Isotope signature and elemental characteristics of subsurface formations around deep-laying coal seams probed by means of atomic and nuclear-based techniques.

A systematic investigation on the isotopic and elemental signature, for both stable and radioactive elements, and mineral contents was performed to examine the characteristics of subsurface formations collected at different depths between 3.962 km and 4.115 km around deep-laying coal seams located under the Marmarica plateau in Egypt. Concentrations of major and minor oxides (Na2O, MgO, Al2O3, SiO2, SO3, K2O, CaO, TiO2, MnO, ΣFeO + Fe2O3, SrO, ZrO2, and BaO) were determined by X-ray fluorescence and dependencies among these concentrations revealed the type and sort of the formations. Organic contents were determined by Fourier Transform infrared spectroscopy to investigate the variation of the CO/CC bonding ratio with depth. Rare earth elements (REE), specifically Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were determined by inductively coupled plasma mass spectrometry while actinoids were detected by the radioactive decay of its daughter nuclei. The results showed a high trapping of REE elements and actinoids in layers above the coal seams which indicates the occurrence of aqueous flow followed by possible sorption in these layers. The mobility of the fluid was investigated using the process radioactive decay series between Ra226 and Ac228 from one side and their daughters from the other side.