Facilitated Cd(II) transport across CTA polymer inclusion membrane using anion (Aliquat 336) and cation (D2EHPA) metal carriers

PIMs have been involved as affinity membranes for recovery of metals (Cd, Pb, Zn) by facilitated transport from aqueous solutions under different speciation forms, either anionic or cationic. The motivation of this work is to compare the efficiency of the recovery process in the case of Cd(II) using extractants such as D2EHPA and Aliquat 336 that can form complexes with the cation Cd²⁺ or the anions CdCl₃⁻ and CdCl₄²⁻, respectively. The maximal Cd(II) recovery factors obtained in 8 h are 97.5% and 91.8% with D2EHPA and Aliquat 336, respectively. Although the transport fluxes with both carriers are not strongly different (ca. 2 μmol m⁻² s⁻¹), the recovery process in case of mixture of metals is better achieved with Aliquat 336. PIMs have shown a very good stability and a constancy of the transmembrane transport flux over 12 replicate measurements, each one lasting for 8 h repeated every 24 h.     

Novel copolyesters based on poly(alkylene dicarboxylate)s: 1. Thermal behavior and biodegradation of aliphatic-aromatic random copolymers

In order to improve the thermal and mechanical properties of the poly(butylene 1,12-dodecanedioate), some novel aliphatic-aromatic random copolyesters have been prepared by starting from 1,4-butanediol and different molar ratio of 1,12-dodecanedioc acid and terephthalic acid. The samples were characterized by ¹H NMR and the molecular structure was correlated with the crystalline phase present, the level of crystallinity, the glass transition temperature, the mechanical behavior, and the biodegradability. In particular, the copolymer containing the 70 mol% of PBT repeating units notably improves the thermal and mechanical properties of the poly(butylene 1,12-dodecanedioate) towards those of PBT and maintains a very high thermal stability, but loses the biodegradability of the poly(alkylene dicarboxylate). Therefore, for this class of aliphatic-aromatic copolymers the chemical composition must be carefully chosen to reach a compromise between good thermal and mechanical performances and biodegradability, according to the necessity.     

Study of the chemical derivatization of zearalenone and its metabolites for gas chromatography-mass spectrometry analysis of environmental samples

This study compares different silylation procedures of zearalenone and its metabolites: alpha-zearalenol, beta-zearalenol, zearalanone, alpha-zearalanol and beta-zearalanol for gas chromatography-mass spectrometry (GC-MS) analysis. Four silylating agents among the most frequently used to derivatize polar organic compounds were tested: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N,N-diethyltrimethylsilylamine (TMSDEA) and a commercial mixture of N,O-bis(trimethylsilyl)acetamide, trimethylchlorosilane and N-trimethylsilyimidazole. Previous studies showed that the addition of polar and/or basic solvents can significantly improve the yield of a reaction of derivatization. In this work, four solvents were tested: pyridine, dimethylformamide, acetonitrile and acetone. The influence of each solvent was studied as a function of the silylating agent/solvent ratio. The influences of the temperature and of the reaction time on the reaction yields were also evaluated. A GC-MS quantitation method associating methanol chemical ionization and selected ion storage with three ions was developed and successfully tested on a reconstituted sediment spiked in zearalenone and its metabolites.     

Electrochemical Characterization of Self‐Assembled Monolayer of a Novel Manganese Tetrabenzylthio‐Substituted Phthalocyanine and Its Use in Nitrite Oxidation

Manganese phthalocyanine MnPc(SPh)₄ has been synthesized and used to form self assembled monolayers on gold electrodes. The well packed SAM monolayer was characterized by analyzing the blocking of a number of Faradic processes by cyclic voltammetry, evaluating the electrical characteristics of the modified electrode by electrochemical impedance and imaging the modified surface by electrochemical scanning microscopy. Finally, MnPc(SPh)₄‐SAM modified electrode displayed an electrocatalytic behavior toward the oxidation of nitrite.     

Transamination chemistry of sodium TMP-zincate: synthesis and crystal structure of a chiral amidozincate

In a new type of reactivity for sodium TMP-zincate [(TMEDA)NaZn((t)Bu)(2)(TMP)] (1), transamination reactions with the amines diisopropylamine, DA(H), hexamethyldisilazane, HMDS(H) and chiral (R)-N-benzyl-alpha-methylbenzylamine have produced new sodium amido-di-tert-butyl zincates (all structurally characterised) with concomitant loss of TMP(H).     

The structure of Fe(III) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

To establish the structure of ferric ions in strongly alkaline (pH > 13) environments, aqueous NaOH solutions supersaturated with respect to Fe(III) and the solid ferric-hydroxo complex salts precipitating from them have been characterized with a variety of experimental techniques. From UV measurements, in solutions of pH > 13, only one kind of Fe(III)-hydroxo complex species was found to be present. The micro crystals obtained from such solutions were proven to be a new, so far unidentified solid phase. M?ssbauer spectra of the quick-frozen solution and that of the complex salt indicated a highly symmetrical ferric environment in both systems From the EXAFS and XANES spectra, the environment of the ferric ion in these solutions (both native and quick-frozen) and in the complex salt was found to be different. In the complex salt, the bond lengths are consistent with an octahedral coordination around the ferric centres. In solution, the coordination geometry of Fe(III) is most probably tetrahedral. Our results demonstrate that in strongly alkaline aqueous solutions, ferric ions behave very similarly to other structurally related tervalent ions, like Al(III) or Ga(III).     

Absolute radiance imaging using parametric image amplification

We show that parametric image amplification can be used to achieve a 2D radiance map directly expressed in photons per spatiotemporal mode. Radiance images of incoherent signals with less than one photon per mode (typically 10(-2)) are resolved.