Acidity: A Key Parameter in Zeolite-Templated Carbon Formation.

This work reveals the crucial role of zeolite acidity in the synthesis of zeolite-templated carbons (ZTCs). While textural and chemical properties appear to be independent from acidity at a given synthesis temperature, the spin concentration in hybrid materials appears to be strongly impacted by the zeolite acid site concentration. The electrical conductivity of the hybrids and resulting ZTCs are closely related to the spin concentration in the hybrid materials.

Secondary Organic Aerosol Formation from Aromatic Alkene Ozonolysis: Influence of the Precursor Structure on Yield, Chemical Composition, and Mechanism.

The influence of the precursor chemical structure on secondary organic aerosol (SOA) formation was investigated through the study of the ozonolysis of two anthropogenic aromatic alkenes: 2-methylstyrene and indene. Experiments were carried out in three different simulation chambers: ICARE 7300L FEP Teflon chamber (ICARE, Orléans, France), EUPHORE FEP Teflon chamber (CEAM, Valencia, Spain), and CESAM evacuable stainless steel chamber (LISA, Créteil, France). For both precursors, SOA yield and growth were studied on a large range of initial concentrations (from ∼60 ppbv to 1.

Chalcogen substitution: Effect of oxygen-by-sulfur exchange on structural and spectroscopic properties of flavonols.

Quantum chemical calculations using density functional theory have revealed that the substitution of the ketone group by a thioketone one doesn't significantly change the structure of 3-hydroxyflavone. Notably, the strong intramolecular hydrogen bond involving the hydroxyl function is preserved if the O atom is substituted by an S atom, but also by Se or Te atoms. However, fundamental modifications are observed in both absorption and emission electronic spectra upon substitution, particularly the non-fluorescent behavior of the flavothione.

Photodecomposition of iodinated contrast media and subsequent formation of toxic iodinated moieties during final disinfection with chlorinated oxidants.

Large amount of iodinated contrast media (ICM) are found in natural waters (up to μg.L(-)(1) levels) due to their worldwide use in medical imaging and their poor removal by conventional wastewater treatment. Synthetic water samples containing different ICM and natural organic matter (NOM) extracts were subjected to UV254 irradiation followed by the addition of chlorine (HOCl) or chloramine (NH2Cl) to simulate final disinfection.

The complexation of AlIII, PbII, and CuII metal ions by esculetin: a spectroscopic and theoretical approach.

UV-visible absorption spectroscopy combined with quantum chemical calculations and, notably, Time-Dependent Density Functional Theory were used to probe the structure of metal complexes with esculetin in dilute aqueous solution, at pH = 5. For the 1:1 complex formation, the studied metal ions can be classified according to their complexing power: aluminum(III) > copper(II) > lead(II). For the three complexes, a chelate is formed with the fully deprotonated catechol moiety and an absorption band is observed at the same wavelength.

Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber.

The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.