SUZIMARA ROVANI
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Artigo IPEN-doc 25738 Application of biochar from agro‑industrial waste in solid‑phase extraction for the determination of 17β‑estradiol from aqueous solution2019 - ROVANI, S.; MEDEIROS, L.F.; LIMA, E.C.; FERNANDES, A.N.In this study, the biochar produced from coffee wastes and eucalyptus sawdust was employed as an adsorbent in solid-phase extraction devices for the determination of 17β-estradiol from aqueous solution. Parameters such as adsorbent mass, solvent type, eluent volume, ionic strength, breakthrough volume, and the cartridge reuse were evaluated. The best experimental conditions for solid-phase extraction concerning adsorbent mass, elution solvent, eluent volume, ionic strength, breakthrough volume, and cartridge reuse were established. The most suitable conditions for 1.0-mL cartridge were: mass of 50 mg, elution solvent 5.0 mL of acetonitrile/water 90:10 (v:v), 0.003 mol L−1 NaCl concentration, and 17β-estradiol solution volume 50.0 mL. The solid-phase extraction results showed that, although 17β-estradiol recovery was about 60%, the removal efficiency was 100% and the cartridges of 200 and 500 mg can be reused eight and four times, respectively, without any decrease in adsorption capacity. The results demonstrate the potential use of biochar as new adsorbent in solid-phase extraction devices for the removal of estrogens in aqueous solution.Artigo IPEN-doc 25729 Kinetic study of uranium removal from aqueous solutions by macaúba biochar2019 - GUILHEN, SABINE N.; ROVANI, SUZIMARA; PITOL FILHO, LUIZILDO; FUNGARO, DENISE A.Macaúba (Acronomia aculeata) is a palm tree native of the Brazilian savanna and a valuable renewable source of vegetable oil for human consumption and biodiesel production. In this study, the potentiality of the macaúba endocarp for biochar (BC) production was demonstrated. Moisture, density, elemental and molecular composition, along with TGA, FTIR, and XRD analyses were performed for the endocarp. Adsorption of uranyl ions, U(VI), from aqueous solutions was studied by batch technique using BC produced by slow pyrolysis of the endocarp at 350 °C (BC350). The effect of contact time on the removal of U(VI) by BC350 was evaluated. Linear and non-linear kinetics models were employed and the best fit for the experimental data was achieved for pseudo-first order non-linear model. The adsorption equilibrium was attained after 180 min of contact time and the equilibrium adsorption capacity achieved was of 400mg g-1. Finally, BC350 was characterized by SEM, FTIR, WDXRF, and XRD techniques.Artigo IPEN-doc 24783 Highly pure silica nanoparticles with high adsorption capacity obtained from sugarcane waste ash2018 - ROVANI, SUZIMARA; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A.Silica nanoparticles (SiO2NPs) from renewable sources can be used in very different materials, such as paints, membranes for fuel cells, Li-ion batteries, adsorbents, catalysts, and so on. Brazil is the world’s largest producer of sugarcane and generates huge amounts of sugarcane waste ash (SWA), which is a Si-rich source. This study investigates a method to produce highly pure SiO2NPs from SWA. The SiO2NPs were characterized by inductively coupled plasma optical emission spectroscopy, scanning and transmission electron microscopy (TEM), X-ray diffraction analyses, specific surface area and pore distribution, UV and Fourier transform infrared spectroscopy, and thermogravimetric analyses and applied as an adsorbent material in the removal of acid orange 8 (AO8) dye from aqueous solution. The SiO2 content was 88.68 and 99.08 wt % for SWA and SiO2NPs, respectively. TEM images of SWA and SiO2NPs exhibit drastic alterations of the material size ranging from several micrometers to less than 20 nm. The SiO2NPs showed a specific surface area of 131 m2 g–1 and adsorption capacity of around 230 mg g–1 for acid orange 8 dye. Furthermore, the recycling of the SiO2NPs adsorbent after AO8 adsorption was very satisfactory, with reuse for up to five cycles being possible. The results indicate that it was possible to obtain highly pure silica in a nanosize from the waste material and produce an adsorbent with high adsorption capacity and the possibility of reuse.Artigo IPEN-doc 23147 Green synthesis and characterization of biosilica produced from sugarcane waste ash2017 - HELENO, RODRIGO A.; REIS, THAIS V. da S.; ROVANI, SUZIMARA; FUNGARO, DENISE A.In this study, ash fromsugarcane waste was used in the synthesis of biosilica using alkaline extraction followed by acid precipitation. Different parameters that could influence the silica particle synthesis were evaluated. The ash and synthesized biosilica were characterized by a combination of spectroscopic and chemical techniques such as XRD, XRF, SEM, particle size analyser, N2 adsorption analysis, TGA, and FTIR. The best condition for biosilica production was achieved with fusion method and aging temperature of 80∘C for 1 h during gel formation. X-ray powder diffraction pattern confirms the amorphous nature of synthesized silica.The purity of the prepared silica was 99% silica which was confirmed bymeans of XRF.Theexperimental data suggest that the sugarcane waste ash could be converted into a value-added product, minimizing the environmental impact of disposal problems.