SUZIMARA ROVANI
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Artigo IPEN-doc 26782 Extração de sílica a partir das cinzas de resíduo da cana-de-açúcar em diferentes condições de extração alcalina2019 - FUNGARO, D.A.; ROVANI, S.Uma amostra de cinzas geradas durante a queima de resíduos de cana-de-açúcar foi triturada com NaOH sólido variando-se a relação cinzas: NaOH (m/m). As misturas foram submetidas ao processo de fusão a 450 oC por 1 h. Após o resfriamento, a sílica da massa fundida foi lixiviada para a fase líquida na forma de silicato de sódio. Seguindo a separação do sólido e do líquido, partículas de sílica foram precipitadas pela adição de ácido sulfúrico até pH 7 à solução de silicato de sódio. O rendimento das amostras mostrou-se constante e uma pureza de 89% foi alcançada. As amostras de cinzas e de sílica produzidas foram caracterizadas por difração de raios-X, fluorescência de raios-X e análise elementar.Artigo IPEN-doc 26758 Caracterização físico-química das propriedades de cinzas de cana-de-açúcar de diferentes usinas brasileiras2019 - ROVANI, S.; CARVALHO, F.; SANTOS, J.; RAMOS, N.; MORANDI, M.; SALDANHA, M.; FUNGARO, D.O interesse em transformar biomassa em novas fontes de energia e novos materiais vem fomentando estudos em todo o mundo. As cinzas resultantes da queima de palha e bagaço de cana, por exemplo, é um material rico em sílica. No presente estudo, amostras de cinzas de resíduos de cana-de-açúcar foram coletadas nas usinas de Cerradinho (Chapadão do Céu, GO), Iracema (Iracemápolis, SP) e Guaíra (Guaíra, SP), localizadas em regiões onde os solos são classificados como Latossolos. As cinzas foram caracterizadas pelas técnicas de XRD, EDX, MEV, espectroscopia no IV e DTG. A maioria das amostras de cinzas apresentou sílica como principal constituinte (42-69%) e a sílica na forma cristalina em todas. Diferenças significativas nas concentrações de outros elementos foram observadas.Resumo IPEN-doc 26531 Comparative study of methods for the synthesis of silica nanoparticles from sugarcane waste ash2019 - ROVANI, SUZIMARA; FUNGARO, DENISE; CARVALHO, FELIPE; SANTOS, JONNATANAdding value to agro-industrial solid waste is a challenge for sustainable and green chemistry. Brazil is the worlds largest producer of sugarcane, producing about 633 million tons per year, and generates huge amounts of sugarcane waste ash (SWA) which is a rich source of silica. Therefore, the development of a process related to the use of this raw material rich in Si for the production of silica nanoparticles (SiNPs) is fundamental. SiNPs are presently applied in paints, biopolymers, catalysts, adsorbents, among others [1]. In this study, SiNPs were produced from SWA by different routes and yield and purity of products obtained were evaluated. The synthesis of SiNPs was carried out by the two-step method. First, NaOH was mixed with SWA, and the resultant mixture was fused at 350 C for 30 min or 1 h, varying the ash:NaOH ratio (1:1.5 or 1:2). After, was added distilled water in the funded solid and refluxed for 1 h to leave all the sodium silicate dissolved in the aqueous medium [2]. Then, HCl or H2SO4 6.0 mol L-1 was added, dropwise, until pH decrease to 2.0. The yield of SiNPs extraction was around 67 % for samples obtained with ash:NaOH ratio 1:1.5, 30 min or 1 h of muffle and HCl solution. So, fusion time was not significant for the yield of the synthesis. Subsequent experiments were conducted at 30 min, ash:NaOH (1:2) and HCl or H2SO4 (Table 1). The yield of silica nanoparticles extraction was 93 % and 67 % with HCl and H2SO4, respectively. The silica obtained with H2SO4 showed lower yield, but higher purity, when compared to the silica obtained with HCl. The yield of silica extraction was higher with ash:NaOH ratio 1:2 and with the HCl. However, the highest purity was obtained with H2SO4.Capítulo IPEN-doc 26704 Removal of Crystal Violet dye from aqueous solution using ash-based adsorbent materials2019 - FUNGARO, DENISE A.; ROVANI, SUZIMARA; BERTOLINI, THARCILA C.R.; FILHO, FLAMARION F.Crystal Violet (CV) is widely used for various purposes and enters into the aquatic systems from the effluents of textile, paint, medical and biotechnological industries. A considerable amount of this dye is lost during manufacturing and processing operations. Contaminated wastewater containing CV must be treated before releasing in the environment because it is highly cytotoxic and carcinogenic to mammalian cells, present mitotic poisoning nature and is nonbiodegradable being classified as a recalcitrant molecule. This chapter reports the removal of CV dye from water using surfactant-modified zeolite from coal fly ash (MZSF), surfactant-modified zeolite from coal bottom ash (MZSB) and nanosilica from sugarcane waste ash (SiO2NP). The adsorbent materials were characterized to obtain chemical and mineralogical composition and others physicochemical properties. The adsorption kinetic of CV onto adsorbents was discussed using the pseudo-first order, pseudo-second order, and Elovich models. The Langmuir and Freundlich isotherm models were used to describe the equilibrium adsorption data. The maximum adsorption capacities were 36.7 mg g-1 and 21.1 mg g-1 for CV/MZSF and CV/MZSB, respectively. The adsorption process of CV/SiO2NP achieves equilibrium in 60 min of contact time, and the maximum adsorption capacity was 117.98 mg g-1. Application of the adsorbent materials synthesized from agricultural waste and coal combustion products can ensure the sustainability and cost-effectiveness of treating effluent containing CV dye, especially effluent from the textile industries generated in large quantity.Artigo IPEN-doc 26399 An alternative and simple method for the preparation of bare silica nanoparticles using sugarcane waste ash, an abundant and despised residue in the Brazilian industry2019 - ROVANI, SUZIMARA; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A.Sugarcane waste ash, a Si-rich waste product, is generated in large quantities and creates a serious disposal problem in the Brazilian ethanol-sugar industry, affecting the environment and public health. Here, a simple method capable of generating bare silica nanoparticles utilizing this residue is demonstrated. Firstly, the crystalline silica present in sugarcane waste ash (SWA) was converted into amorphous by melting a mixture of sodium hydroxide and SWA at 550 °C for 1 h. The silica nanoparticles (SiO2NPs) were formed by lowing pH. This production process of SiO2NPs from SWA was optimized varying the ash:NaOH mass ratio, increasing the silica extraction up to 96%. The sample’s composition was characterized by total X-ray fluorescence spectroscopy, morphology and physical-chemical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, specific surface area measurements, Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA), followed by use as adsorbent for the removal of methylene blue dye. With this process of extraction, nanoparticles smaller than 100 nm were generated, with a surface area of 63 m2 g-1 and a maximum adsorption capacity of 37 mg g-1 for methylene blue. The results indicate a successful process for obtaining an adsorbent from an industrial waste product using a cost effective and rapid synthesis procedure rendering renewable product.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 25894 Low cost silica nanoparticles biosorbent obtained from sugarcane waste ash2018 - ROVANI, S.; SANTOS, J.J.; CORIO, P.; FUNGARO, D.A.Sugarcane waste ash, a Si-rich source, is generated in large quantity and can create a serious disposal problem. The production of silica nanoparticles (silicaNPs) from sugarcane waste ash varying ash:NaOH mass ratio was evaluate. The samples were characterized by total X-ray fluorescence spectroscopy, SEM, TEM, XRD, surface area and pore distribution, FTIR and TGA and applied as biosorbent for methylene blue dye removal. The yield of silicaNPs extraction remained constant from ash:NaOH mass ratio 1:1.5. Si content was 77.32 wt.% and 94.89wt. % for sugarcane waste ash and silicaNP 1:1.5, respectively. SilicaNP 1:1.5 presented particles smaller than 100 nm, surface area of 63 m2 g-1 and adsorption capacity of 37 mg g-1 for methylene blue. The results indicate that was possible to obtain a biosorbent, from a renewable source, with low cost and with easy and fast synthesis procedure.Resumo IPEN-doc 25150 Adsorption of bisphenol-A in aqueous solution using silica nanoparticles obtained from sugarcane ash2018 - ROVANI, SUZIMARA; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A.Scientists around the world have searched minimize problems related to the incorrect disposal of solid wastes and water contamination. Brazil, for example, is the largest producer of sugarcane in the world, generates around 3-12 million of tons ash/year or more, and this waste can be transformed into valueadded material. In this study, we tried to solve two problems at the same time, manufacturing an adsorbent material and applies it in the remediation of contaminated water with bisphenol-A (BPA), an endocrine disrupting compounds, which alters plasma sex hormone levels in fishes [1]. The silica nanoparticles were synthetized through the addition of silicate obtained from sugarcane ash in the solution of water/butyl alcohol (1:1) with 2.5% wt. of hexadecyltrimethylammonium bromide under constant stirring. Then, 0.5 mol L-1 H2SO4 solution was added to suspension until pH 4. The nanosilica formed was washed with distilled water, filtered and dried. The silica nanoparticles and BPA adsorbed on silica were characterized by different techniques. The maximum BPA adsorption capacity obtained was 80 mg g-1. From TEM images (Fig. 1A-B) of the silica nanoparticles it is seen that all particles has less than 20 nm. Fig. 1C shows the infrared spectra of samples. The band at 1058 cm-1 is due to the Si–O–Si asymmetric stretching, the band at 965 cm-1 is due to Si-OH bending vibrational absorption, the bands at 799 and 446 cm-1 are due to the Si–O–Si symmetric stretching. The presence of other bands in the blue spectra are attributed of BPA adsorbed on silica nanoparticles, at 554 cm-1 is due to aromatic ring deformation vibration of di-substituted benzenes, at 834 cm-1 is assigned to C-H vibrations out of the plane and at 1512 cm-1 is due to aromatic C=C stretching vibration [2]. The results of characterization of the silica nanoparticles manufactured showed that the material presents potential to be employed as adsorbent for remediation of water contaminated with endocrine disrupting compounds.Resumo IPEN-doc 25008 Adsorption study of acid orange 8 dye using silica nanoparticles obtained from sugarcane ash2017 - ROVANI, SUZIMARA; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A.Developing of new adsorbents becomes a very important need, especially because of the increase of contaminants present in rivers, oceans and any other water body capable of became potable. Biosorbents has a special feature, because they can solve two problems at the same time, once they are prepared from a natural source, giving a utility for wasted materials, and bioremediate a water body, adsorbing contaminants on their surface. In this context, the properties of a biosorbent prepared from sugarcane ash by surfactant mediated synthesis has been studied to the adsorption of acid orange 8 dye, a model molecule, aiming future applications for removal of emerging contaminants of water. According to the results of adsorption kinetic (Fig. 1A), the acid orange 8 dye removal was higher than 89% and 95% in 4 h of contact time for an initial concentration of 200 and 150 mg L-1, respectively. FTIR-ATR analyses (Fig. 1B) indicated the presence of bands: at 799 and 446 cm-1 are due to symmetric stretching of siloxane groups, at 1058 cm-1 is due the Si–O–Si asymmetric stretching, at 2925 cm-1 and 2850 cm-1 are due to the bending of –CH3 and –CH2, respectively, for silica-CTAB sample and additionally, at 1031, 689 and 641 cm-1 are due sulfur groups (S=O), out-of-plane deformation of ring and aromatics groups, respectively, of acid orange 8 dye. In TGA analysis (Fig. 1C), the peak between 150 to 235 °C for silica-CTAB sample has been attributed to the unbound CTAB less stabilized bonding sites on the silica surface due to hydrophobic– hydrophobic interactions of interdigitated CTAB and the peak around 256 °C indicates a stronger bonding of the surfactant to the silica surface due to the electrostatic binding of the ammonium cation head group to the electronegative silica surface [1]. For the silica-CTAB + dye sample, the substitution of the interdigitated CTAB of a second layer by dye was observed by the disappearance of the DTG peak between 150 to 235 °C. The displacement the DTG peak of 256 for 300 °C and appearance of the DTG peak around 435 °C are related to the dye adsorption. These aspects demonstrate the potential of silica nanoparticles obtained from sugarcane ash as new biosorbent for removal of organic compounds, such as, dye from aqueous solution and can be used to alleviate environmental problems.