Laser-evaporated iron was deposited onto solid oxygen at 20 K to produce stratified samples consisting of Fe and O₂ layers. The Mössbauer spectra of these samples were acquired in order too investigate their oxidation states and chemical properties. The reaction produced the trivalent iron oxide particles whose size varied depending on the amount of Fe atoms deposited on the solid oxygen. Samples which had smaller amounts of Fe produced smaller iron oxide particles having superparamagnetism. When the sample was annealed at 293 K, the size of the iron oxide particles became larger due to aggregation. The sample with the thickest Fe-layer (180 nm) had a pure α-Fe layer above the iron oxide layer, and the divalent iron oxide was formed after annealing at 293 K.

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Zeolite A was chemically synthesized and characterized using X-ray diffraction, X-ray fluorescence, and thermal analysis. The sorptive removal of cesium and strontium ions from aqueous waste solution using synthetic zeolite A was investigated. Experiments were carried out as a function of pH, solute concentration, and temperature (298-333 K). Analysis of the respective rate data in accordance with three kinetic models revealed that the intraparticle diffusion was the rate determining step for the sorption of both studied ions. Values of the pseudo first order and pseudo second order rate constants and the particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy and thermodynamic parameters of free energy (ΔG^*), enthalpy (ΔH^*), and entropy (ΔS^*) of activation for each sorption process were calculated from the linearized form of Arrhenius equation.

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Kinetics of ion-isotopic exchange reaction was studied using industrial grade ion exchange resin Duolite A-113. The radioactive isotopes ¹³¹I and ⁸²Br were used to trace the ion-isotopic exchange reaction. The experiments were performed in the temperature range of 26.0°C to 43.0°C and the concentration of external ionic solution varying from 0.005 M to 0.100 M. For bromide ion-isotopic exchange reaction, the calculated values of specific reaction rate, initial rate of bromide ion exchange, and amount of bromide ions exchanged were obtained higher than that for iodide ion-isotopic exchange reaction under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions.

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Cosmic-ray-induced ²⁶Al in terrestrial silicate rock was remeasured by accelerator mass spectrometry (AMS) in order to confirm the value reported more than 30 years ago. The result of (5.2±1.0) ×10^{6 26}Al atoms/g SiO₂ for the surface rock sample was consistent with the previous result determined by a low background γ-γ coincidence spectrometry system within experimental uncertainties. The lower amount of ²⁶Al was found in the deeper part of the rock samples. From the result, the surface exposure age and the erosion rate at the sampling location were estimated to be 1.4×10⁵ y and 3.7×10^-4 cm/y, respectively.

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Apricot stone shells were carbonized under certain chemical and thermal conditions. The produced sorbent had been impregnated with different concentrations of oxalic and succinic acids. They were physically characterized and used for preconcentration of U (VI) and Th (IV) from acidified aqueous solutions. Batch equilibrium studies revealed that a quantitative preconcentration could be achieved at pH ∼2 for U (VI) and ∼1.3 for Th (IV). The equilibrium time was extended up to 24 h for U (VI) and 40 min for Th (IV). The modified sorbent showed a superior extractability for U (VI) and Th (IV) with distribution coefficient mean alues of 2084 and 7808 mL g^-1, respectively. The sorption capacity values are 2.39 and 8.47 mg g^-1 for U (VI) and Th (IV) sorption onto apricot stone anchored with oxalic acid and 2.3 and 9.18 mg g^-1 for sorbent anchored with succinic acid. Desorption of loaded uranium ions was effectively achieved using 1 M HNO₃ while only 0.5 M HNO₃ was recommended to release retained thorium ions.

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⁵⁷Fe Mössbauer spectroscopy has revealed that carboxylato bridged binuclear iron complex, [Fe^II Fe^III (bpmp) (ena) ₂] (ClO₄) ₂, exhibits a mixed-valence state depending on temperature, where bpmp = 2, 6-bis[bis- (2-pyridylmethyl) -aminomethyl]-4-methylphenol and Hena = enanthic acid. Both of the polycrystalline sample and the film sample prepared by dispersing the complex in poly (methyl methacrylate) (PMMA) have been investigated. The rate of the intramolecular electron transfer between iron (II) and iron (III) ions for the polycrystalline sample abruptly increases above ca. 200 K, and that for the film sample is slightly increase in the temperature range of 80 K to 295 K. The results show that the intermolecular interactions affect the intramolecular electron transfer of the binuclear mixed-valence iron complex.

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