Kinetic modeling analysis for the removal of cesium ions from aqueous solutions using polyaniline titanotungstate

Polyaniline titanotungstate has been synthesized by incorporation of organic polymer polyaniline into the inorganic precipitate of titanotungstate. This material was characterized using X-ray, IR and TGA studies. The influences of initial concentration of metal ions, particle size and temperature have been reported. The comparison of composite and inorganic materials was studied and indicating that the composite material is better than the inorganic in selectivity of Cs⁺ ions. Thermodynamic parameters, such as changes in Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) have been calculated. The numerical values of ΔG decrease with an increase in temperature, indicating that the sorption reaction of adsorbent was spontaneous and more favorable at higher temperature. The positive values of ΔH correspond to the endothermic nature of sorption processes and suggested that chemisorptions were the predominant mechanism. A comparison of kinetic models applied to the sorption rate data of Cs⁺ ions was evaluated for the pseudo first-order, the pseudo second-order, intraparticle diffusion and homogeneous particle diffusion kinetic models. The results showed that both the pseudo second-order and the homogeneous particle diffusion models were found to best correlate the experimental rate data. Self diffusion coefficient (D_i), Activation energy (Ea) and entropy (ΔS^*) of activation were also computed from the linearized form of Arrhenius equation.     

Use of some Inorganic and Organic Compounds as Decontaminants for Cobalt-60 and Caesium-134 by Clover Plant Grown on Inshas Sandy Soil

Outdoor lysimeter experiments were carried out to elucidate the effect of 4 inorganic and 3 organic salts on ⁶⁰Co and ¹³⁴Cs uptake and dry matter yield of three cuts of clover in the soils of Inshas. A new concept was proposed for assessing the difference in capacity of soil to supply radionuclides to plants as affected by applied inorganic or organic compounds. A relation of plant tissue radionuclide content with time can be expressed in an exponential equation with corresponding regression coefficients. When the same plant species is grown on the same soil differing only in the applied compounds (e.g. Fe-EDDHA, Fe-DTPA, Fe-OAC, Fe(COO)₂, Al(OH)₃, Ca(H₂PO₄)₂, Fe₂O₃) the derived equation will change. Differences of either Co or Cs accumulation with time between control and any other treatment were evaluated. The data also show that Fe-DTPA is preferred for ⁶⁰Co as enhancing compound for plant uptake (for decontamination use), compared with other applied salts, on the other hand, any tested salts did not significantly effect ¹³⁴Cs taken by clover. It was also found that more than 70% of the total cobalt uptake was accumulated in the roots which indicate that Co is less mobile in plants than Cs.     

Erratum to: “Effects of TiO2 on the hydrophilicity of сotton/polyester (50/50) blend fabric under UV irradiation”

Russian Journal of Applied Chemistry -     

Adsorption Studies of Copper Sulfate on Hydrogels of Poly(Amido-Amines)

Abstract

The interaction between the active groups of polymeric gels of poly(amido-amines) such as poly(acrylamide-diallyldiethyl ammonium chloride) “cationic gel p(AM-DADEAmCl)” and poly(acrylamide-sodium acrylate-diallyldiethyl ammonium chloride) “amphoteric gel p(AM-AANa-DADEAmCl” with copper sulfate have been carried out by using polymeric gels of different swelling degree and different amine percent.

The capacity toward cations decreases with increasing the amine percent and the swelling degree but the capacity toward anions such as (SO₄₎ ^2- decreases with increasing swelling degree and increases with increasing the amine percent. These polymeric gels interact with copper sulfate at pH value >5 to form a crosslinked structures. Spectroscopic studies showed that the mechanism of crosslinking formation is a bond formation between the active group of polymeric chains and copper sulfate. The bond formation depends on the nature of the polymer chain. It was also found that the amide groups form complexes with hydrated cations, while both carboxylate and ammonium groups interact by ion-exchange mechanisms.     

Speciation of Neptunium Migration in under Groundwater

The migration of radionuclides with groundwater into the environment of a radioactive waste repository is an important aspect in evaluating the safety assessment of such repositories. The potential transport and fate of these radioactive species are dependent upon their speciation and the geochemical behavior of the predominant ones. The speciation of different valence states of neptunium [Np(IV, V and VI)] and their migration behavior are investigated. The data revealed that the uptake is highly dependent upon pH and the distribution coefficient (K _d) is depressed by the presence of organic ligands. The relative migration velocities (V _n) of the valence states relative to that of groundwater, in the concerned area, clarified that Np(V) is the most mobile species and their transport rates are highly accelerated by the presence of humic acid. Also, a radionuclide dispersion model was applied to elucidate the migration behavior of these radioactive species in the selected site and to quantitatively predict their concentrations at different distances in both x and z directions over long time scales.     

Synthesis,properties and effect of ionizing radiation on sorption behavior of iron silico-antimonate

Incorporation of iron oxide into silico-antimonate of different Si/Sb molar ratios introduced a class of dual salts ion exchangers with advanced ion exchange properties. Physicochemical and equilibrium studies have been carried out to understand the ion exchange properties of these materials. Apparent investigation indicated that iron incorporation into silico-antimonate yields materials having excellent mechanical properties. On the basis of distribution studies, the materials were found to be highly selective for Sr²⁺ or Ce³⁺ depending on their Si/Sb molar ratios. Diffractogram, thermogram, IR spectra and sorption performance of crystalline FeSiSb (114) indicated that no detectable structural changes after an exposure up to 100 kGy of γ-rays. Effect of reaction temperature on the exchange process was investigated and the respective thermodynamic parameters were calculated.     

Resolution and assignement of absolute configuration to the (+)- and (−)-cis and trans 3,4-diol metabolites of the anti-juvenile hormone precocene I

The cis and trans 3,4-diol metabolites of precocene I have been prepared inoptically pure form and their absolute configurations have been assigned by independent nmr and CD techniques.     

Enlarged omnidirectional photonic gap in one dimensional ternary plasma photonic crystals that contain metamaterials

We study the dynamics of multipartite quantum correlations measured by the lower bound of concurrence and quantum discord in a three-qubit system coupled to an XY spin chain. For the initial pure GHZ and W state, we find the lower bound of entanglement is more robust than the quantum discord against the decoherence induced by the spin environment. But for the Werner state, the sudden death of discord is not observed even in the presence of entanglement sudden death. By comparing the evolutions for the GHZ and W states, we show that the W state preserves more quantum correlations than the GHZ state. In addition, we put research emphasis on the relation between the dynamics of multipartite quantum correlations and the quantum phase transition of the spin environment.