Studies on column adsorption of arsenic (V) from a real water on dehpa-impregnated XAD-8 resin

Arsenic contamination of drinking water is a widespread problem of international interest. Arsenic is released from the soil through natural processes or due to human activities. In the paper was studied the possibility of removal of arsenic from drinking water using a column filled with Amberlite XAD-8 resin impregnated with di-(2-ethylhexyl) phosphoric acid (DEHPA). The efficiency of arsenic removal from water was established by studying the dependence of arsenic residual concentration and arsenic removal degree on the volume of the water passed over the adsorbent material. The adsorption process had an efficiency of -90% and the arsenic residual concentration was smaller than 10 pg/L. The studies concerning the influence of other ions present in water (Na+, K+, Ca2+, Mg2+, Fen+, Mnn+, NO2", N H /, NO3', PO43', CF) showed that these ions do not interfere with arsenic adsorption process

Use of impregnated resins as adsorbents in view of heavy metals removal from aqueous solutions

The presence of heavy metal ions in environment is a major concern because of their toxicity to many life forms. Heavy metal ions can be removal from water by adsorption on solid support. In the present work, we tested the adsorption of metal ions on solvent impregnated resin (SIR). Di-(2-ethylhexyl)-phosphoric acid (D2EHPA) has been chosen as an extractant for the purpose of this study. The interaction between XAD4 resin and D2EHPA was evaluated by physico-chemical methods of analysis (EDX and SEM). The experimental studies on adsorption of metal ions were carried out on Pb2+, Cu2+, Cd2+, Cr3+, Ni , Fe3+, Zn2+ and Ca2+. A separation method was developed for metals ions and was investigated the influence of contact time on the residual concentration of metal ions, on their removal efficiency and on the adsorption capacity of resin towards metal ions

Synthesis and Fluorescence Mechanism of the Aminoimidazolone Analogues of the Green Fluorescent Protein: Towards Advanced Dyes with Enhanced Stokes Shift, Quantum Yield and Two-Photon Absorption

Novel small-molecular analogues the green fluorescence protein (GFP) chromophore are synthesised to expand and improve this fluorophore family and to deepen the understanding of their fluorescence mechanism. The introduction of an aminophenyl substituent and the repositioning of the hydroxyl group to enable strong intramolecular hydrogen bonding, not only enhances fluorescence emission, but also results in an increased Stokes shift and a considerable red shift. Experimental and computational results describe a dual fluorescence involving both excited-state intramolecular proton transfer and internal charge transfer (ESIPT?ICT) mechanism. The further improvement of the photophysical properties via the systematic variation of dialkylamino substituents at a single position of the chromophore led to a two-orders of magnitude enhancement in the quantum yields. In addition, the novel compounds also have significant two-photon absorption, which widens the possibilities for applications in the field of bioimaging

Continuous spark plasma synthesis of Au/Co binary nanoparticles with tunable properties

We present here a scalable and environmentally friendly gas phase technique employing atmospheric pressure electrical spark discharge plasmas for the production of Au/Co binaries, an effective catalyst system for the decomposition of hydrogen-rich compounds, such as ammonium borane. We demonstrate that Au/Co alloy nanoparticles can be produced via the spark plasma-based technique. The possibility of varying the morphology and phase structure via real time heat treatment of the generated aerosol to form Au/Co/CoO particles with continuous control over a wide particle compositional range (from 24 to 64 at.% [Co]/([Co] + [Au]) content) is also demonstrated. Since our spark-based approach is proven to be capable of providing reasonable particle yields, these results may contribute to the transition of lab-scale, nanocatalyst-based hydrogen storage systems to real world applications