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Publications (2)5.53 Total impact

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    ABSTRACT: Some intermediates were identified during the course of non-catalytic wet air oxidation (WAO) of cellulose. Concentrations of by-products were determined in function of temperature and reaction time. This study also showed that hydroxyl radicals (HO*) and hydrogen peroxide (H2O2) play the role of intermediates in the initial phase of the oxidation reactions. Hydroxyl radicals were detected by the electron spin resonance spectroscopy coupled to the spin trapping technique using the 5,5-dimethyl 1-pyrroline N-oxide (DMPO) as spin trap agent. The spin adduct (DMPO/ HO*), resulting from the trapping of HO* with DMPO, showed a characteristic electron spin resonance signal which was inhibited when catalase was added, indicating that HO* was provided from H2O2. These transient species were only observed at the beginning of the reaction and were not oxygen dependent.
    Water Research 12/2002; 36(19):4821-9. DOI:10.1016/S0043-1354(02)00205-1 · 5.53 Impact Factor
  • N. Ricq · S. Barbati · M. Ambrosio ·
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    ABSTRACT: The aim of this work is to optimize the degradation yield of an activated sludge and to study the reaction mechanism on a cellulose model compound. This optimization is performed with a Simplex design with four parameters: reaction temperature (280-350 °C), injected air pressure (40-60 MPa), reaction time (10-45 minutes) and COD concentration (0.5-5 g L-1). The better yield obtained on TOC concentration is 82 5% at 330 °C. Over this temperature, the yield substantially decreases. The use of cellulose as a model compound for activated sludge confirms optimization results and leads to the identification of by-products and free radical species participating in the reaction. Two major organic compounds have been detected: 4-oxo pentanoïc acid and 3-oxo butanoïc acid, and three types of radicals: HO°, CO2°- and °CH(OH)CH3.
    Analusis 11/2000; 28(9):872-877. DOI:10.1051/analusis:2000159