RESUMO A indústria têxtil consome um volume significativo de água no processo de tingimento das fibras. As águas residuais geradas no processamento, além de turvas, devido à presença de corantes que não se fixam na fibra durante o processo de tingimento, são prejudiciais ao ambiente aquático e também aos seres humanos. Esse efluente deve passar por um processo de tratamento antes de ser lançado em corpos hídricos. O tratamento de águas contaminadas com o uso de bioadsorventes possui como vantagens o baixo custo de material e reciclagem de resíduo natural. Baseado no exposto, o objetivo deste trabalho foi avaliar a capacidade de adsorção do corante têxtil Azul Reativo BF-5G em casca de mandioca (Manihot Esculenta Crantz), resíduo proveniente da indústria de farinha de mandioca. A casca de mandioca foi lavada, seca e classificada. Os ensaios de adsorção, em banho finito, foram realizados em diferentes condições de pH, granulometria e temperatura. As capacidades máximas de adsorção, em 24 horas de contato, para as diferentes condições de pH, granulometria e temperatura, foram as seguintes: (qmáx=85,18 mg.g-1; pH=1; 30 °C; 16 mesh); (qmáx=52,30 mg.g-1; pH=0; 30 °C; 32 mesh); (qmáx=92,92 mg.g-1; pH=0; 30 °C; 48 mesh). O processo de adsorção foi espontâneo e exotérmico, o que leva a concluir que a casca de mandioca (Manihot Esculenta Crantz) é um potencial adsorvente para o corante Azul Reativo BF-5G, garantindo economia e praticidade no tratamento desse efluente.

ABSTRACT The textile industry consumes a significant amount of water in the fiber dyeing process. The wastewater generated in the processing, in addition to turbid, due to the presence of dyes that do not stick to the fiber during the dyeing process, are harmful to the aquatic environment and also to humans. This effluent must undergo a treatment process before being released into water bodies. The treatment of contaminated water with the use of bioadsorbers has the advantages of low material cost and recycling of natural waste. Based on the above, the objective of this work was to evaluate the adsorption capacity of the textile dye Blue Reactive BF-5G in cassava peel (Manihot Esculenta Crantz), residue from the cassava flour industry. The cassava peel was washed, dried and classified. The adsorption tests, in finite bath, were carried out under different conditions of pH, granulometry and temperature. The maximum adsorption capacities, in 24 hours of contact, were as follows: (qmax=85.18 mg.g-1; pH=1; 30 °C; 180 rpm; 16 mesh); (qmax=52.30 mg.g-1; pH=0; 30 °C; 180 rpm; 32 mesh); (qmax=92.92 mg.g-1; pH=0; 30 °C; 180 rpm; 48 mesh). The adsorption process was spontaneous and exothermic, which leads to the conclusion that the cassava peel (Manihot Esculenta Crantz) is a potential adsorbent for the Reactive Blue BF-5G dye, ensuring economy and practicality in the treatment of this effluent.

RESUMO No presente trabalho foi realizada a estimativa das emissões dos gases de efeito estufa (CO2eq), monóxido de carbono (CO), óxido de nitrogênio (NOx), material particulado (MP), aldeído (RCHO) e hidrocarboneto não metano (NMHC) dos veículos licenciados nos cinco primeiro meses do ano de 2020 no Brasil. Os resultados foram comparados com as emissões veiculares da frota licenciada no mesmo período do ano de 2019 a fim de verificar o impacto da pandemia de COVID-19 nos referidos licenciamentos, nas emissões e, consequentemente, na qualidade do ar do país. Os resultados apontaram redução de 14% nas emissões dos gases de efeito estufa, com diminuição observada para todos os veículos, exceto para os caminhões semipesados, que tiveram incremento nas emissões de gases de efeito estufa de 12,8%. Os demais poluentes também reduziram, em 12,5% para o CO, em 29,6% para o NOx, em 24,1% para o MP, em 21,5% para o RCHO e em 16,3% para o NMHC. Por fim, quanto ao total de poluentes acumulados, entre todos os veículos analisados, os únicos que tiveram aumento nas emissões em relação a 2019, de 2,1%, foram as motocicletas com tecnologia flexfuel, que são abastecidas preferencialmente com etanol hidratado. Com isso, pôde-se concluir que a pandemia da COVID-19, por meio das medidas de restrição e isolamento social adotadas no país para frear a transmissão da doença, impactou positivamente a qualidade do ar no Brasil no período analisado.

ABSTRACT The estimated emissions of greenhouse gases (CO2eq), carbon monoxide (CO), nitrogen oxide (NOx), particulate matter (PM), aldehyde (RCHO) and non-methane hydrocarbon (NMHC) from vehicles licensed in the first five months of 2020 in Brazil were calculated in the present study, and the results compared with vehicular emissions from the licensed fleet in the same period of the year 2019, in order to verify the impact of the COVID-19 pandemic on these permits, emissions and, consequently, air quality in the country. The results showed a 14% reduction in greenhouse gas emissions, with a decrease observed for all vehicles, except for semi heavy trucks, which had a 12.8% increase in GHG emissions. The other pollutants also decreased, being 12.5% for CO, 29.6% for NOx, 24.1% for PM, 21.5% for RCHO, and 16.3% for NMHC. Finally, in relation to the total accumulated pollutants, among all vehicles analyzed, the only ones that had a 2.1% increase in emissions in relation to 2019 were the motorcycles with flexfuel technology, which are preferably fueled with hydrated ethanol. Thus, it was concluded that the COVID-19 pandemic, through the measures of restriction and social isolation adopted in the country to curb the transmission of the disease, had a positive impact on air quality in Brazil during the analyzed period.

ABSTRACT The synthesis of ceramic materials such as ferrite has been widely studied in recent years, due to their properties that make these materials have excellent applications in technology, as well as in photocatalytic processes and as catalysts. To obtain the copper ferrite phase the EDTA-Citrate complexation method was used, varying pH (5, 7 and 9), temperature (600, 800 and 1000 °C) and calcination time (2, 7 and 12 h). Composition, morphology and structural analyzes were performed by X-ray fluorescence spectroscopy, X-ray dispersive energy, scanning electron microscopy and X-ray diffraction, respectively. Crystalline phase of copper ferrite (CuFe2O4) with tetragonal structure and secondary phase of Fe2O3 and CuO was verified by XRD analysis. Regarding the chemical composition analyzes, percentage deviations of the samples and the theoretical value for copper and iron were calculated. It was obtained minimum values of 0.16 - 0.08% (atomic%, EDS) and 16 - 8% (atomic%, XRF) in relation to copper and iron, respectively, for the sample obtained under pH 9, calcined at 600 °C for 12 h. The variation of the synthesis condition via EDTA-Citrate directly influenced the morphology of copper ferrite, presenting agglomerated particles, pore formation, irregular spheres, and even powder sintering.

In this paper, NiMoO4 powder was synthesized by the complexation method combining EDTA-Citrate. The behavior of the NiMoO4 material in the ethyl transesterification reaction was evaluated by analyzing the acidity index under specified reaction conditions. The results showed that NiMoO4 crystallized at 800 °C with a total mass loss of 85%, presenting a monoclinic structure, free of secondary phases, high degree of crystallinity and average crystallite size of 140 nm. The particles had heterogeneous sizes and shapes, but with well-defined contours. The increase in the mass of NiMoO4 in the reaction medium reduced the acidity index (0.8 mgKOH.g-1 with 15 wt.%). Despite the use of the minimum molar ratio (1:3), the ethyl route being less reactive and the use of the operating temperature close to the alcohol evaporation temperature, NiMoO4 showed promising catalytic potential in the transesterification process.

BaCeO3-based ceramics are ionic and electronic conductors that can be applied to oxygen sensors, solid oxide fuel cells and oxygen permeable membranes. However, the low chemical stability at high temperatures of these materials motivates studies involving doping of A and/or B sites of the perovskite structure. In this context, the present work aimed to synthesize a new BaCe0.8Pr0.05Cu0.15O3-δ material using the chemical route of complexation which combines EDTA-Citrate with pH variation. The powders obtained at pH 3 or 11 and calcined up to 900 ºC are thermally unstable. The cubic perovskite BaCe0.8Pr0.05Cu0.15O3-δ with crystallite size between 99.4 nm and 131.6 nm was obtained along with barium carbonate traces. In the powders calcined at 1000 ºC the pH increase decreases the amount of barium carbonate (17.3% to pH 3, 3.4% to pH 7 and 1.8% to pH 11), but increases the size of grains with irregular shapes.

Cerium molybdate semiconductive nanoparticles were synthesized by the EDTA-citrate combined complexation method. Gel thermal degradation behavior, phase formation, morphology, composition and band gap of cerium molybdate powders were characterized by TG/DSC, XRD, SEM/EDS and DRS analysis, respectively. The nanoparticles were synthesized by fixing the pH of the reaction medium to 9, producing an organometallic gel which was heated to 230 ºC obtaining a precursor powder. The precursors were calcined in a temperature range of 450 - 800 ºC for 3 h. The cerium molybdate powders were characterized and the phase evolution, morphology and band gap changes with the increase of calcining temperature were investigated. It was observed that the calcining temperature directly influences the formation of the crystalline structure, appearance of other phases in the materials and the particle size.