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.     

Crystal packing,vibrational studies,DFT calculations of a new hybrid nickel (II)‐complex and its application in Heck and Sonogashira cross‐ coupling reactions

We particularly investigate a new material [Ni(C₁₂H₁₂N₂)(H₂O)₄]SO₄ that it was hydrothermally synthesized by reaction of 5,5’‐dimethyl‐2,2’‐bipyridne, denoted (dmbpy), metal salt and sulfuric acid. The large crystals are characterized by X‐ray single crystal diffraction, infrared, Raman spectroscopy and DFT calculation. The thermogravimetric analysis indicated that the dehydration occurs in two steps, leading to an anhydrous compound. At room temperature, the complex crystallises in the centrosymmetric space group P2₁/c with the following parameters a = 9.492 (7) Å, b = 9.539 (7) Å, c = 18.411 (1) Å, β =102.616 (1)°, V = 1626.8 (2) ų and Z = 4. The asymmetric unit contains one free SO₄^2‐counter‐ion and [Ni(dmbpy)(H₂O)₄]²⁺ complex cation. The crystal structure of the complex is built up from infinite parallel two‐dimensional planes, containing all the components of the structure and perpendicular to the axis b. The aqua ligands are connected to the sulfate anion via O‐H…O hydrogen bonds that stabilize the three‐dimensional network. The catalytic activity of the complex was examined in the coupling reactions of Heck and Sonogashira in the presence of different bases in various organic solvents under ultrasonic irradiation. The obtained results show that this type of complex can be considered as an effective catalyst for these coupling reactions. The ultrasonic activation results the encouraging yields for a short period of time: 30‐45 min.     

Entropy squeezing of multi-photon field interacting with a single Cooper-pair box

We investigate the entropy squeezing and entanglement of the Cooper-pair box interacting with multi-photon cavity field. The field is prepared initially in the coherent state, while the Cooper-pair box is assumed to start from a mixed state. We find that the number of photons and the detuning parameters play an important role in the entropy squeezing and entanglement. We observe that the entropy squeezing can be used as a good indicator of the entanglement. This study opens promising perspectives for creating remote quantum information processing networks.     

Novel crowned-porphyrin ligands. Synthesis and conformational studies

Three new macromolecules—a cryptand, a bis-macrocycle, and a tris-macrocycle—have been synthesized as chelating ligands for cation binding. They result from the surprisingly simple reaction of various bis-functionalized meso-aryl porphyrins with a diaza-crown ether coupled one to each other through either one or several urea linkage(s). Indeed, the latter induces some additional rigidity in comparison with the usual amide linkage found in such macromolecules. Various strategies are reported to optimize the yield of the reaction towards the formation of a cofacial singly-linked crown-porphyrin, which is the most promising ligand to stabilize large cations such as bismuth(III) as the angle between the two macrocycles can vary.     

Heat transfer with thermal relaxation to a perfectly conducting polar fluid

The model of boundary-layer equations for a perfectly conducting fluid proposed by M. Ezzat [1] is applied to study the heat transfer with one relaxation time from a non-isothermal stretching sheet on the flow of a polar fluid. The method of the successive approximation is adopted for the solution of two-dimensional problem. The effects of various material parameters on the velocity, angular velocity, and temperature are discussed and illustrated graphically.     

Systematic Low-Energy Optical Model Potential for $$\alpha$$ -Nucleus Elastic Scattering

Physics of Atomic Nuclei - The elastic scattering of $$\alpha$$ particle from $${}^{89}$$ Y, $${}^{92}$$ Mo, $${}^{106-116}$$ Cd, $${}^{112}$$ Sn, and $${}^{144}$$ Sm nuclei ( $$Z=39{-}62$$ ) at...     

Ball Milling Pretreatment of Oil Palm Biomass for Enhancing Enzymatic Hydrolysis

Oil palm biomass, namely empty fruit bunch and frond fiber, were pretreated using a planetary ball mill. Particle sizes and crystallinity index values of the oil palm biomass were significantly reduced with extended ball mill processing time. The treatment efficiency was evaluated by the generation of glucose, xylose, and total sugar conversion yields from the pretreatment process compared to the amount of sugars from raw materials. Glucose and xylose contents were determined using high-performance liquid chromatography. An increasing trend in glucose and xylose yield as well as total sugar conversion yield was observed with decreasing particle size and crystallinity index. Oil palm frond fiber exhibited the best material yields using ball milling pretreatment with generated glucose, xylose, and total sugar conversion yields of 87.0, 81.6, and 85.4 %, respectively. In contrast, oil palm empty fruit bunch afforded glucose and xylose of 70.0 and 82.3 %, respectively. The results obtained in this study showed that ball mill-treated oil palm biomass is a suitable pretreatment method for high conversion of glucose and xylose.