Abstract Structured catalysts were prepared, characterized and evaluated in NO3 - removal from drinking water. Different suspensions containing a previously optimized PdCu/5wt% ZrO2-Al2O3 powder catalyst (hereinafter PdCu/5ZAp) were prepared and deposited on cordierite monoliths by washcoating. The effect of suspension concentration, the particle size, the immersion number, the use of suspension stabilizer agent, and an alumina pre-coating on the coating adherence and catalytic performance were studied. All the prepared structured catalysts were active for the elimination of NO3 - and presented good selectivity to N2 (> 93%) in synthetic water samples. The catalyst performance was related to the amount of deposited catalyst. The highest activity and the best coating adherence were obtained with the structured catalyst prepared by a single immersion in a 14 wt% concentration suspension, which was obtained from the powder catalyst milled for 10 h and stabilized with colloidal alumina. This catalyst also showed good activity when it was reused for four cycles and when it was evaluated with real water samples.

ABSTRACT The iron-manganese mixed monolithic catalysts were obtained by impregnation from nitrates as precursors. A monolithic support was studied with and without alumina as surface generator. The characterization consisted in XRD, SEM, Adherence test, SBET and TPR. The monolith was evaluated in the combustion of ethyl acetate. The preparation method was very satisfactory in terms of reproducibility and adherence of the deposited phase. The higher activity of IFeMnx with respect to Al3FeMnx may be attributed for the formation of the solid solution where the Fe is introduced to the bixbyite structure. However, the presence of defective MnOx species in monoliths without alumina which might help to improve their performance is observed.

The aim of this work was to study the effect of two precipitation pHs and three different ageing times on the preparation of simple LaFeO3 perovskites for their use as catalysts in the methane combustion. Absorption atomic spectroscopy (AAS), BET specific area measurements, XRD analysis, Raman, XPS, TGA and DTA analysis, TPR and TPO profiles revealed that significant changes in chemical composition, surface area and surface composition was produced at pH 8 when the ageing time was changed, leading to solids with different catalytic activity in methane combustion. At the higher precipitation pH studied, pH 10, the physical chemistry properties for all the samples obtained at different ageing times are almost identical, and therefore the solids exhibit similar activities in the combustion reaction. The catalysts were found to be active for methane combustion, and the effect of the perovskite’s structure and surface properties became more important