Abstract Copper oxide (CuO) is a heterogeneous catalyst applied with success in several systems like vegetable oils transesterifications. The Ce-dopoing CuO is a promisor material with a potential improve catalysis performances. In this work, CuO and Ce-doping CuO were synthesized by the microwave hydrothermal method in only 5 min at low temperature (100 oC) without templates or other petroleum dependent organic substances, using only copper and cerium nitrates and sodium hydroxide as a precursors. Both materials were applied as photocatalysts for the degradation of remazol golden yellow dye (RNL). X-ray diffraction analysis showed that CuO and Ce-doped CuO has monoclic copper oxide structure without secondary phases. SEM analysis showed the Ce-doping full modify the CuO powder morphology. The dye RNL degradation rate of Ce-doping CuO was bigger than pure CuO and the expensive CeO2.

Abstract The study aimed to evaluate the influence of Crotonblanchetianus Baill essential oil on the sensory parameters of fermented milk drinks with yellow mombin pulp. The milk drinks analyzed contained milk and whey from goat origin, water-soluble soy extract, yellow mombin pulp, and Crotonblanchetianus Baill essential oil (CBEO) in the following proportions: 0.0, 0.0035; 0.0070, and 0.0105 g/L according to the Artemia salina toxicity test. The extraction of essential oil from the Crotonblanchetianus Baill leaves was carried out using hydrodistillation by steam. The sensory profile of the fermented milk drink was obtained through Quantitative Descriptive Analysis. The CBEO influenced the color of yellow mombin, brightness, viscosity, woody flavor, appearance, and flavor attributes. The samples were also approved in the acceptance test, with no statistical difference between treatments. Therefore, it was concluded that the addition of CBEO promoted changes in the sensory characteristics of the fermented milk drink with yellow mombin pulp for the appearance and flavor attributes. However, it did not negatively influence the acceptance of the analyzed product.

CuO structures were synthesized by microwave hydrothermal treatment using two different mineralizing agents (NaOH and NH4OH) and were evaluated as photocatalysts. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The XRD patterns indicated the formation of the monoclinic phase in both samples with 13.78 and 14.23 nm crystallite size. SEM analysis showed different agglomerates morphologies based on the mineralization agent employed. The CuO nanostructure synthesized with NH4OH presented agglomerated like-plates which results in a spherical shape, whereas the material synthesized with NaOH presented an agglomerate of larger plates. Both samples showed photocatalytic activity against RNL azo dye. The quasi-spherical shape CuO material reached 93 % of the discoloration.