No abstract

Two aluminum-boron oxide catalysts were produced via a sol-gel method at pH 3 and 4 during the solution mixing step of the synthesis, these materials were employed in thermocatalytic degradation of coniferyl aldehyde (CA), which was used as a probe molecule of the lignin polymeric molecule and is comprised of the repetitive monomers coniferyl, sinapyl, and paracoumaryl. The two * Corresponding author.

La-, Mn- and Fe-doped ZrO2 was synthesized using the sol-gel method, washcoated on cordierite monoliths and used in trichloroethylene (TCE) combustion. A sol from sol-gel synthesis method was used to obtain the zirconia washcoatings. The washcoatings deposited on the cordierite monolith materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and N2 physisorption measurements, being the crystalline phase determination the most correlate with the catalytic activity. The washcoat properties were correlated to their performance in trichloroethylene combustion. The catalytic washcoatings contained a mixture of crystalline tetragonal ZrO2 and monoclinic ZrO2, and the monoclinic phase exhibited strong interactions with the α-cordierite crystalline phase. For the kinetic tests, the mass transfer into the washcoated monolith channels was evaluated using a recently developed model for the internal mass transfer coefficients for diffusion and reactions in catalytic monoliths. This model involves three resistances. In a plot of the overall resistance as function of the Thiele modulus was determinate that he reaction occurred in the kinetically controlled regime. The kinetic data were fit to two Langmuir–Hinshelwood (LH) models, and the reaction rate was fitted as a function of the trichloroethylene inlet concentration. The adsorption parameters obtained with both LH models were validated based on thermodynamic criteria for the changes in the standard enthalpy of adsorption(${\Delta}H_{ads}^0$) and standard total entropy of adsorption (${\Delta}S_{ads}^0$). It was found that adsorbed TCE and oxygen atoms should be more mobile over the catalyst, which had a higher proportion of tetragonal phase than monoclinic phase of zirconia. The La, Fe-doped catalyst exhibited the highest activity, mainly due the presence of tetragonal zirconia.