Adsorption and thermodynamic behaviour of U(VI) on the Tendurek volcanic tuff

In this work, sorption of uranium ions on volcanic tuff collected from the deposits located at the Tendurek of Eastern Turkey was investigated in batch technique. The effect of different parameters such as pH of the medium, contact time, uranium concentration and temperature were investigated. The maximum removal of U(VI) was found to be 68% at pH 5.0, initial U(VI) concentration of 75 mg L⁻¹ and 30 °C. Thermodynamic parameters, such as enthalpy of adsorption ∆H°, free energy change ∆G° and entropy change ∆S° have been also calculated and interpreted. The suitability of the Langmuir, Freundlich and Dubinin-Radushkhevic adsorption models to the equilibrium data was investigated for uranium-volcanic tuff system. The results suggest that volcanic tuff can be used as efficient and cost effective adsorbents for uranium ion removal.     

Polymer wiring of insulating electrode materials: An approach to improve energy density of lithium-ion batteries

The poor electronic conductivity of LiFePO₄ has been one of the major issues impeding it from achieving high power and energy density lithium-ion batteries. In this communication, a novel polymer-wiring concept was proposed to improve the conduction of the insulating electrode material. By using a polymer with tethered “swing” redox active molecules (S) attached on a polymer chain, as the standard redox potential of S matches closely the Fermi level of LiFePO₄, electronic communication between the redox molecule and LiFePO₄ is established. Upon charging, S is oxidized at the current collector to S⁺, which then delivers the charge (holes) to the LiFePO₄ particles by intermolecular hopping assisted by a “swing” – type motion of the shuttle molecule. And Li⁺ is extracted. Upon discharging, the above process is just reversed. Preliminary studies with redox polymer consisting of poly (4-vinylpyridine) and phenoxazine moiety tethered with a C₁₂ alkyl chain have shown promising result with carbon-free LiFePO₄, where effective electron exchange between the shuttle molecule and LiFePO₄ has been observed. In addition, as the redox polymer itself could act as binder, we anticipate that the polymer-wiring concept would provide a viable approach to conducting-additive and binder free electrode for high energy density batteries.     

An efficient microwave-assisted synthesis of novel quinolone–triazole and conazole–triazole hybrid derivatives as antimicrobial and anticancer agents

1,2,4-Triazole-fluoroquinolone and 1,2,4-triazole–conazole hybrids are designed, synthesized, and investigated in vitro against a variety of common diseases. The structure of the newly synthesized compounds are characterized from spectral data (IR, ¹H NMR, ¹³C NMR, and LC–MS). The antibacterial activity against both Gram-positive and Gram-negative bacteria is shown to be enhanced by many of the produced compounds. Also, some of the products are found to have strong antiproliferative effects aganist HeLa cervical cancer cells, whilst demonstrating cytotoxic effects toward normal cells.