Navegação IPEN por Autores IPEN "ROVANI, SUZIMARA"

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  • IPEN-DOC 25150

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J. ; CORIO, PAOLA; FUNGARO, DENISE A. . Adsorption of bisphenol-A in aqueous solution using silica nanoparticles obtained from sugarcane ash. In: AMERICAN CHEMICAL SOCIETY. DIVISION OF CELLULOSE & RENEWABLE MATERIALS. NATIONAL MEETING & EXPOSITION, 255th, March 18-22, 2018, New Orleans, LA. Abstract... 2018.

    Abstract: 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.

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  • IPEN-DOC 25008

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J. ; CORIO, PAOLA; FUNGARO, DENISE A. . Adsorption study of acid orange 8 dye using silica nanoparticles obtained from sugarcane ash. In: PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st, November 27-30, 2017, Guarujá, SP. Abstract... 2017.

    Abstract: 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.

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  • IPEN-DOC 26399

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A. . An alternative and simple method for the preparation of bare silica nanoparticles using sugarcane waste ash, an abundant and despised residue in the Brazilian industry. Journal of the Brazilian Chemical Society, v. 30, n. 7, p. 1524-1533, 2019. DOI: 10.21577/0103-5053.20190049

    Abstract: 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.

    Palavras-Chave: sugar cane; wastes; adsorbents; silica; nanoparticles; ethanol fuels; ashes; sodium hydroxides; agriculture; agricultural wastes

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  • IPEN-DOC 27156

    AZEVEDO, LUCIANA C. de ; ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; DIAS, DJALMA B. ; NASCIMENTO, SANDI S.; OLIVEIRA, FABIO F.; SILVA, LEONARDO G.A. ; FUNGARO, DENISE A. . Biodegradable films derived from corn and potato starch and study of the effect of silicate extracted from sugarcane waste ash. ACS Applied Polymer Materials, v. 2, n. 6, p. 2160-2169, 2020. DOI: 10.1021/acsapm.0c00124

    Abstract: The growing concern with the amount of plastic materials found in the oceans makes it necessary to develop biodegradable materials that have low toxicity to marine animals and humans, but at the same time are resistant to the actions of microorganisms such as fungi or bacteria. On the other hand, agricultural waste rich in inorganic materials (such as silica) is often discarded, while it could be reused as a source of raw material. Considering these points, sodium silicate solution extracted from sugarcane waste ash was utilized to prepare biodegradable bioplastics based on corn starch and potato starch. The starch-based bioplastics were produced by casting and characterized by several physical-chemical techniques evaluating tensile strength, elongation at break, color analyses, transparency, opacity, moisture, and biodegradation assay. Bioplastics prepared with corn starch presented better physical, mechanical, and thermal properties and optical quality than bioplastics based on potato starch. The samples called CS3 and PS3, with 5.0% glycerol, were the most resistant to tensile strengths of 0.73 and 0.36 MPa, respectively. On the other hand, the highest elongation at break values were found for the samples with 7.5% glycerol (CS9, 52.90% and PS9, 49.33%). Corn starch-based bioplastics were more thermally resistant (CS3, 152.86 °C and CS9, 135.20 °C) when compared to potato starch-based bioplastics (PS3, 140.39 °C and PS9, 127.57 °C). In general, the addition of sodium silicate solution improved the mechanical and thermal properties of both types of bioplastics. The potato starch-based bioplastics were biodegraded in 5 days, while those made from corn starch took almost 40 days. The inclusion of sodium silicate inhibited fungal growth for both corn starch and potato starch bioplastics. The results suggest that sodium silicate solution obtained from renewable sources can be incorporated into starch-based bioplastics for production of biodegradable packaging with antifungal activity.

    Palavras-Chave: biodegradation; agriculture; sugar cane; agricultural wastes; bagasse; chemical composition; ashes; maize; potatoes; starch; plastics; sustainability; sodium silicates; environment; polymers

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  • IPEN-DOC 26531

    ROVANI, SUZIMARA ; FUNGARO, DENISE ; CARVALHO, FELIPE ; SANTOS, JONNATAN. Comparative study of methods for the synthesis of silica nanoparticles from sugarcane waste ash. In: ACS NATIONAL MEETING & EXPOSITION, 257th, March 31 - April 4, 2019, Orlando, FL, USA. Abstract... Washington, DC, USA: American Chemical Society, 2019.

    Abstract: Adding 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.

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  • IPEN-DOC 27252

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; GUILHEN, SABINE N. ; CORIO, PAOLA; FUNGARO, DENISE A. . Fast, efficient and clean adsorption of bisphenol-A using renewable mesoporous silica nanoparticles from sugarcane waste ash. RSC Advances, v. 10, n. 46, p. 27706–27712, 2020. DOI: 10.1039/d0ra05198e

    Abstract: Even with all the biological problems associated with bisphenol-A (BPA), this chemical is still being widely used, especially in thermal paper receipts. In this study, renewable mesoporous silica nanoparticles (MSN), obtained from sugarcane ash, functionalized with hexadecyltrimethylammonium (CTAB) were applied as an adsorbent in the removal of BPA from the aqueous solution. The versatility of this material and its BPA adsorption capacity were tested at different pH values, being practically constant at pH between 4 and 9, with a slight increase in pH 10 and a greater increase in pH 11. The removal time evaluation indicates a very fast adsorption process, removing almost 90% of BPA in the first 20 min of contact. The kinetic model indicates a monolayer formation of BPA molecules on the MSN-CTAB surface. The maximum adsorption capacity (Qmax) was 155.78 mg g-1, one of the highest found in literature, and the highest for material from a renewable source.

    Palavras-Chave: organic compounds; plastics; adsorption; sugar cane; ashes; bagasse; polymers; aqueous solutions; silica; nanoparticles; cleaning

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  • IPEN-DOC 23147

    HELENO, RODRIGO A. ; REIS, THAIS V. da S. ; ROVANI, SUZIMARA ; FUNGARO, DENISE A. . Green synthesis and characterization of biosilica produced from sugarcane waste ash. Journal of Chemistry, n. 6129035, 2017. DOI: 10.1155/2017/6129035

    Abstract: 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.

    Palavras-Chave: synthesis; biological materials; silica; ashes; sugar cane; wastes; bagasse; waste product utilization

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  • IPEN-DOC 24783

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; CORIO, PAOLA; FUNGARO, DENISE A. . Highly pure silica nanoparticles with high adsorption capacity obtained from sugarcane waste ash. ACS Omega, v. 3, n. 3, p. 2618-2627, 2018. DOI: 10.1021/acsomega.8b00092

    Abstract: 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.

    Palavras-Chave: nanoparticles; sugar cane; ashes; wastes; silica; agricultural wastes; adsorption

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  • IPEN-DOC 25729

    GUILHEN, SABINE N. ; ROVANI, SUZIMARA ; PITOL FILHO, LUIZILDO; FUNGARO, DENISE A. . Kinetic study of uranium removal from aqueous solutions by macaúba biochar. Chemical Engineering Communications, v. 206, n. 11, p. 1365-1377, 2019. DOI: 10.1080/00986445.2018.1533467

    Abstract: 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.

    Palavras-Chave: kinetics; uranium; aqueous solutions; adsorption; trees; coconut palms; carbon; pyrolytic carbon

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  • IPEN-DOC 24926

    AZEVEDO, LUCIANA C. de; SA, ALESSANDRA S.C. de; ROVANI, SUZIMARA ; FUNGARO, DENISE A. . Propriedades do amido e suas aplicações em biopolímeros. Cadernos de Prospecção, v. 11, n. Edição Especial, p. 351-358, 2018. DOI: 10.9771/cp.v11i2.23173

    Abstract: O uso de amido pelos seres humanos remonta ao Egito antigo, onde papiros datados de 4000 a.c. eram elaborados com amido de trigo. Este carboidrato polimérico é constituído por unidades de glicose que se ligam formando estruturas de amilose e amilopectina, cuja proporção de cada uma dessas frações irá conferir características específicas, atribuindo diferentes aplicações comerciais a esta substancia. Muitos estudos estão sendo conduzidos para encontrar aplicações nobres para o amido, como por exemplo, o melhoramento das propriedades de materiais pela incorporação deste carboidrato como substrato polimérico, especialmente com o intuito de serem empregados em substituição ao plástico. Em relação a isso, pesquisas têm sido realizadas envolvendo a combinação com outros hidrocolóides, adição de novos plastificantes, nanocompósitos e polímeros inorgânicos na obtenção da solução filmogênica com o amido, assim como estão sendo desenvolvidas novas tecnologias de extrusão e secagem dos filmes, incluindo aplicação de radiação gama. O objetivo desta revisão foi apresentar as principais características e o avanço no uso de amido como polímero em filmes biodegradáveis e o interesse da comunidade científica e industrial por essa tecnologia. A prospecção revelou que, além de estar em ascensão desde 1990, a tecnologia de obtenção de biopolimeros está sendo intensivamente aprimorada por países como a China e EUA.

    Palavras-Chave: starch; polymers; inorganic polymers; polysaccharides; plasticity; biodegradation; biotechnology

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  • IPEN-DOC 26704

    FUNGARO, DENISE A. ; ROVANI, SUZIMARA ; BERTOLINI, THARCILA C.R. ; FILHO, FLAMARION F. . Removal of Crystal Violet dye from aqueous solution using ash-based adsorbent materials. In: DUFFET, VICTOR (Ed.). Crystal Violet: Production, Applications and Precautions. Hauppauge, NY, USA: Nova Science Publishers, 2019. p. 1-40, cap. 3.

    Abstract: 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.

    Palavras-Chave: methyl violet; zeolites; coal; ashes; silica; nanomaterials

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  • IPEN-DOC 27707

    AZEVEDO, LUCIANA C. de ; ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; DIAS, DJALMA B. ; NASCIMENTO, SANDI S.; OLIVEIRA, FABIO F.; SILVA, LEONARDO G.A. ; FUNGARO, DENISE A. . Study of renewable silica powder influence in the preparation of bioplastics from corn and potato starch. Journal of Polymers and the Environment, v. 29, n. 3, p. 707-720, 2021. DOI: 10.1007/s10924-020-01911-8

    Abstract: In the present study, 0.5–1.5% silica powder, from sugarcane waste ash, was incorporated into corn and potato starch bioplastics doped with sodium silicate solution to improve the properties of elongation at break and increase the thermal resistance of the bioplastics. The starch-based bioplastics were produced by casting and characterized by color analyses, transparency, opacity apparent, humidity, thickness, tensile strength, elongation at break, FTIR, DSC, SEM, and biodegradation assay. The addition of 0.5% of silica powder improved the elongation at break of the corn starch-based bioplastics. The sample CS5-P0.5 presented the highest percentage of elongation at the break among the studied samples, increased from 59.2% (without silica powder) to 78.9% (with silica powder). For potato starch bioplastic the addition of 0.5% of silica powder did not improve elongation at break but increased the thermal resistance. Increased until 17 °C for PS5-P0.5 sample and until 11 °C for PS7.5-P0.5 sample. The bioplastics of potato starch were biodegraded in 5 days, and those of corn starch took almost 40 days. Silica powder inhibited the growth of fungi in starch bioplastics.

    Palavras-Chave: silica; powders; temperature dependence; thermal conductivity; sugar cane; ashes; silica; biodegradation; plastics

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  • IPEN-DOC 23239

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J. ; CORIO, PAOLA; FUNGARO, DENISE A. . Sugarcane biomass ash as a renewable source of nanosilica. In: IUPAC WORLD CHEMISTRY CONGRESS, 46th; ANNUAL MEETING OF THE BRAZILIAN CHEMICAL SOCIETY, 40th, July 07-14, 2017, São Paulo, SP. Abstract... Durham, NC, USA: International Union of Pure and Applied Chemistry, 2017.

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  • IPEN-DOC 25007

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J. ; CORIO, PAOLA; FUNGARO, DENISE A. . Surfactant mediated synthesis of silica nanoparticles using sugarcane ash waste as renewable source. In: PAN AMERICAN CONGRESS OF NANOTECHNOLOGY, 1st, November 27-30, 2017, Guarujá, SP. Abstract... 2017.

    Abstract: Green silica from renewable source can be used in very different materials, since addictive for construction materials or polymers to traditional products as glass, silicone rubber as well as source for silicon. Brazil is the world’s largest producer of sugarcane and generates huge amounts of sugarcane ash waste (SAW) which is a rich source of silica. This work investigates a method to produce pure silica nanoparticles from SAW. Initially, sodium silicate was obtained from sugarcane ash waste adapting the methodology published by Alves, et al., 2017. Subsequently, sodium silicate was added to a mixture of water/butyl alcohol (1:1) with 2.5% wt. of hexadecyltrimethylammonium bromide under constant stirring at 60 °C. Then, 0.5 mol L-1 sulfuric acid solution was added slowly to suspension until pH 4 and the resulting gel was aged at 60 °C for 8 h. The aged nanosilica gel was washed with distilled water, filtered and oven dried at 120 °C. The silica nanoparticles were characterized by different techniques. In the Figure 1 can be observed energy dispersive spectra (EDS) and transmission electron microscopy (TEM) images of sugarcane ash waste (A and B) and of silica nanoparticles (C and D). EDS of SAW shows the presence of several different elements (being Si, Fe, Al, P, Cl and S more abundant) and only Si and O were observed after synthesis procedure (Cu signal comes from TEM grid). Transmission electron microscopy image of samples exhibit a drastic alterations of the material size ranging from several micrometers (Fig. 1C) to less than 20 nm (Fig. 1D). The results indicate that was possible to obtain pure silica in a nano- size from waste material to reduce disposal and pollution problems.

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  • IPEN-DOC 27702

    GUILHEN, SABINE N. ; ROVANI, SUZIMARA ; ARAUJO, LEANDRO G. de ; TENORIO, JORGE A.S.; MASEK, ONDREJ. Uranium removal from aqueous solution using macauba endocarp-derived biochar: effect of physical activation. Environmental Pollution, v. 272, p. 1-10, 2021. DOI: 10.1016/j.envpol.2020.116022

    Abstract: The main aim of this study was to evaluate options for addressing two pressing challenges related to environmental quality and circular economy stemming from wastage or underutilization of abundant biomass residue resources and contamination of water by industrial effluents. In this study we focused on residues (endocarp) from Macaúba palm (Acrocomia aculeata) used for oil production, its conversion to activated biochar, and its potential use in uranium (U) removal from aqueous solutions. Batch adsorption experiments showed a much higher uranyl ions (U(VI)) removal efficiency of activated biochar compared to untreated biochar. As a result of activation, an increase in removal efficiency from 80.5% (untreated biochar) to 99.2% (after activation) was observed for a 5 mg L 1 initial U(VI) concentration solution adjusted to pH 3 using a 10 g L 1 adsorbent dosage. The BET surface area increased from 0.83 to 643 m2 g 1 with activation. Surface topography of the activated biochar showed a very characteristic morphology with high porosity. Activation significantly affected chemical surface of the biochar. FTIR analysis indicated that U(VI) was removed by physisorption from the aqueous solution. The adsorbed U(VI) was detected by micro X-ray fluorescence technique. Adsorption isotherms were employed to represent the results of the U adsorption onto the activated biochar. An estimation of the best fit was performed by calculating different deviation equations, also called error functions. The Redlich-Peterson isotherm model was the most appropriate for fitting the experimental data, suggesting heterogeneity of adsorption sites with different affinities for uranium setting up as a hybrid adsorption. These results demonstrated that physical activation significantly increases the adsorption capacity of macauba endocarp-derived biochar for uranium in aqueous solutions, and therefore open up a potential new application for this type of waste-derived biochar.

    Palavras-Chave: aqueous solutions; vegetable oils; vegetables; coconuts; uranium; adsorption; chemical activation; activated carbon; charcoal

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✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.