Guilherme Sippel Machado

This work reports the systematic evaluation of the synthetic route used to prepare several layered hydroxide salts (LHS) based on nitrate salts of cobalt, copper, nickel, and zinc and their physicochemical and catalytic properties. Four synthetic methods were investigated: hydrothermal (H), ammonia diffusion (A), mechanochemical (M), and precipitation (P) and the LHS obtained were characterized by different techniques such as X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The influence of the four synthetic methods on the structure of the prepared LHS is discussed, as well as the impacts on their catalytic activity. The synthesized LHS were employed as catalysts for the ketalization of cyclohexanone with methanol and it was observed that the changes in the metal (II) and different synthetic method used to prepare the LHS lead to a substantial impact in the catalytic results, suggesting that these variables are important tools to direct the best and appropriate use of this family of layered solids.

O presente teve como objetivo entender a natureza do trabalho docente nas áreas das ciências exatas, nos colégios estaduais da região do litoral do Paraná. A metodologia de pesquisa pautou-se na abordagem qualitativa com aplicação de questionário direcionado aos professores. Os achados revelam uma série de problemas relacionados às condições de trabalho dos professores, desde as dificuldades das práticas pedagógicas pelo uso das tecnologias, como o incipiente e deficitário plano de carreira, turmas lotadas, perda da autonomia docente e das garantias trabalhistas.

In recent decades, the increasing use of pesticides to improve food productivity has led to the release of effluents that contaminate the environment. To prepare a material that may help to treat effluents generated during agricultural practice, we used a new method based on the non-hydrolytic sol-gel route to obtain zinc photocatalysts in aluminophosphate matrixes. IR spectroscopy, X-ray diffraction, thermal analysis, differential scanning electron microscopy, energy dispersion spectroscopy, and specific surface area and pore volume determined from the nitrogen adsorbed were used to characterize materials treated at different temperatures. X-ray analysis showed how heat-treatment affected the structure of the material: Zn-AlPO₄ in the trigonal and orthorhombic phase was obtained at 750 and 1000 °C, respectively. These phases directly influenced the ability of the material to generate OH radicals. The capacity of the materials to treat effluents was tested in the photodegradation of the pesticide Fipronil. The photocatalytic reactions were monitored by ultraviolet-visible spectroscopy and gas chromatography-mass spectrometry analyses. Zn-AlPO₄ treated at 750 °C showed better photodegradation results--it removed 80% of the pesticide in 2 h when higher mass (150 mg) was tested. Long-time treatment of the effluent with Zn-AlPO₄ treated at 750 °C completely photodegraded Fipronil. GC-MS analysis confirmed the photodegration profile, and only traces of Fipronil were observed after photocatalytic reaction for 120 min in the presence of Zn-AlPO₄ treated at 750 °C under UV radiation.

Anais Encontro Nacional de Jogos e Atividades Lúdicas no Ensino de Química, Física e Biologia (978-65-5941-328-7) - Proposta De Planilha Eletrônica Como Ferramenta Pedagógica Para O Ensino De Química No Ensino Médio