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Desenvolvimento de procedimentos para a síntese e caracterização de catalisadores e de biodiesel
(Universidade Federal de São Carlos, 2017-06-08) Gonçalves, Alexandra Mary; Assaf, José Mansur; https://lattes.cnpq.br/9563312407691130; Nogueira, Ana Rita de Araújo; https://lattes.cnpq.br/7034773971317045; https://lattes.cnpq.br/1292148611034352
ABO3 basic catalysts were synthesized by the nitrate-b-alanine solution combustion method. The catalysts powders were produced by self-combustion in times up to 5 min, presenting high crystallinity and single-phase, without the calcination step. XRD analyses showed that the produced calcium oxides (CaZrO3 and Ca0.9Li0.6Zr0.9O3) presented perovskite structure with the orthorhombic system, whereas a monoclinic structure was observed for Li2ZrO3 oxide, results confirmed with the Rietveld refinement. Different techniques were used to characterize the catalysts, such as MEV-FEG, TPD-CO2, TGA, N2 (BET), ICP OES, MIP-OES, WD-XRF and FT-IR. Different methods of acid decomposition were employed, instead of HF, for elemental analysis of the oxides. Recovery values were observed between 92 and 101%, with low deviations and LOQs. The catalytic activity of the synthesized materials was tested by the reaction of ethyl transesterification with methyl acetate (model reaction). The Ca0.9Li0.6Zr0.9O3 was the most active oxide, reaching 92% conversion to ethyl acetate, followed by oxide Li2ZrO3, with 64% conversion. The CaZrO3 had negligible catalytic activity. Reagent tests of Li-containing catalysts indicated average conversion of about 50% up to the 6° recycle. The Li incorporation to zirconate produced changes in the textural and basic properties, resulting in more efficient and promising catalysts for the transesterification. The Ca0.9Li0.6Zr0.9O3 was also evaluated in the oil transesterification reaction for biodiesel production, with a yield of 60% m/m under mild reaction conditions (molar ratio 1:12 oil/ethanol and 50 °C for 30 min). Although the metallic ions leaching from the most active materials has been detected, no reaction was observed in the homogeneous phase. A system composed of a rotating packed bed reactor and a microwave oven (RPB + MW) was developed for the continuous flow biodiesel production by the ethylic transesterification instant reaction under heterogeneous catalysis. Total ester content of 19% was obtained with 1 min of product collect time, demonstrating a promising system for the proposed application.
Potencial de resíduos orgânicos na atenuação de contaminação por cobre de solo e água
(Universidade Federal de São Carlos, 2017-06-08) Cipoleta, Nathalia Sprovieri; Addad, João Eduardo; https://lattes.cnpq.br/2356106837787562; Assad, Maria Leonor Ribeiro Casimiro Lopes; https://lattes.cnpq.br/0379324550884468; https://lattes.cnpq.br/3863263015621888
The aggravation of environmental problems has stimulated discussion about new ways of producing in the field. The term alternative agriculture covers non-conventional agricultural systems, such as natural, ecological, biodynamic, permaculture, biological, organic and agroecological systems. In addition to organic inputs for fertilization and soil conditioners, crops grown in alternative systems also require natural products to combat pests and plant diseases. Heavy metals such as arsenic, cobalt, copper, lead, and zinc, which occur as impurities in these products, can reach undesirable levels and cause contamination of soil, water, and sediments. The Bordeaux mixture is a fungicide composed of hydrated copper sulphate (CuSO4.5H2O) and quicklime (CaO) and is legalized for use in alternative agricultural systems, but may increase copper (Cu) contents in the soil and affect soil and water quality. The objective of this work was to evaluate the soil and water contamination potential of copper contained in the Bordeaux mixture; ii) to evaluate the retention of Cu in clay soil fertilized with waste and organic conditioners; and iii) estimate the potential for soil and water contamination. Copper contamination potential was evaluated based on a literature review focused on articles, dissertations and theses published, focusing on alternative agricultural production systems. The retention of Cu and its soil and water contamination potential were evaluated by means of a laboratory test using clay tubes filled with clay soil treated with three types of organic materials (Bokashi, coconut fiber, and leonardite) in three doses of Bordeaux mixture. The test lasted 47 days and regular percolate samplings were performed. At the end of the experiment, the content of Cu retained in the soil was determined. Residues and organic conditioners, in all tested doses, retained more than 55% of the applied Cu, even after extraction with strong acid. Bokashi presented the lowest concentration of Cu in the percolate (0.621 mg L-1) and the lowest concentrations retained in the soil, after extraction with weak acid (68.4% in the lowest dose) and with strong acid (59.9% in the highest dose ). Leonardite showed the highest concentration of Cu in the percolate (1.4% in the highest dose) and the highest concentrations retained in the soil, after extraction with weak acid (98.2% in the medium dose) and with strong acid (94.1% in the lowest dose). It is concluded that leonardite, a material rich in humic substances, has high Cu adsorption capacity and may be useful in organic production systems to mitigate contamination of soils and water with Cu.