cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14303859.v1
title: Pyrolysis of the Caupi Bean Pod (Vigna unguiculata): Characterization of Biomass and Bio-Oil

description: The use of agricultural residues for the production of bio-oil is an important alternative to the use of fossil fuels. In this study, the Caupi bean pod (Vigna unguiculata) was characterized and used as biomass in the production of bio-oil. This biomass was evaluated in terms of physicochemical, morphological (scanning electron microscopy (SEM)), and thermal (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)) characterization, lignocellulosic composition, and pyrolysis processes. The pyrolysis was carried out in a stainless steel fixed-bed reactor (260 mm in length and 60 mm in diameter) under atmospheric nitrogen pressure. Pyrolysis was conducted at 550, 600, and 700 °C and N2 gas flow of 2, 5, and 7 mL min-1. The chemical composition of the bio-oils was studied through CHN, TGA, Fourier-transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC-MS). The results confirmed the bean pod’s potential in the thermochemical process. The thermogravimetric analyses demonstrate that there can be a relationship between the components of the principal biomass (cellulose, hemicellulose, and lignin) and the compounds present in the bio-oil. The obtained bio-oils represent bio-products that are rich in compounds of several chemical classes with relevant commercial value such as acids (palmitic, linoleic, oleic, and stearic), alcohols (ethylene glycol), sugars (levoglucosan), and phenols (guaiacol, catechol, phenol, and pyrocatechol).
DOI: 10.6084/m9.figshare.14303858.v1
title: Elemental Composition of Particulate Matter in the Southeastern Brazilian Ceramic Pole by Synchrotron Radiation X-ray Fluorescence Technique (SR-XRF)

description: In the present study, the elemental content of the particulate matter PM2.5 (particulate matter with diameters lower than 2.5 µm) and PM10 (particulate matter with diameters lower than 10 µm) of the Brazilian city of Rio Claro (SP) were analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) in the Brazilian Synchrotron Light Laboratory (LNLS). A fractional sampling of particulate matter (PM) was carried out in two climatic periods (dry and rainy season). The elemental determination of PM2.5 and PM10 included the following elements: Si, S, Ca, K, Ti, Cr, Mn, Fe, Cu, and Zn. Elemental correlation studies, cluster analysis, principal component analysis and enrichment factor determination were performed in order to allow the distinction of the main sources of the emission of PM. The mean elementary contents, especially in PM10, were statistically different to each other between the sampling seasons and higher in dry than in rainy season. The cluster analysis indicated two groups as being the main constituting element groups for the composition of PM in Rio Claro. A major group originated by the resuspension of soil composed by the elements Si, Fe, Ca and K, and a second, minor group composed of S, Ti, Mn, Cu, Cr, and Zn, presumably influenced by vehicular emissions and the regions adjacent ceramic industries.
DOI: 10.6084/m9.figshare.14303857.v1
title: The Catalytic Action of Copper Ions and the Rosemary Extract Antioxidant Effect in the Biodiesel Oxidation Reaction and the Implication in Arrhenius Behavior

description: Biodiesel contains esters in its composition which make it susceptible to oxidation. Among the factors that cause this reaction is the contamination with metal ions. In the present work, it was analyzed biodiesel samples obtained from a mixture containing 39.0% m/m soybean oil, 22.0% m/m beef tallow and 39.0% m/m poultry fat using a methyl route. Copper ions were added to the biodiesel to evaluate its catalytic action in the oxidation reaction, in the presence and absence of rosemary extract. During 192 h of assay, samples containing copper, without extract, showed shorter induction periods, higher rate constants and lower activation energy, when compared to samples containing extract, at the same assay temperature. Copper ions presented a strong catalytic action causing linearity deviations showing a super-Arrhenius behavior, while rosemary extract delayed the oxidative process and showed no linearity deviations.
DOI: 10.6084/m9.figshare.14303855.v1
title: Application of Mixture Design Using Diluted Acid for Extraction of Inorganic Components in Fruits of Casearia fasciculata and Determination by ICP OES: Evaluation by PCA and HCA

description: This study is the first to propose the simultaneous quantification of 10 elements in fruits of Casearia fasciculata by inductively coupled plasma optical emission spectrometry (ICP OES). A method of digestion using dilute nitric acid was optimized by mixture design for extraction of elements in the seed, peel, and pulp of Casearia fasciculata cultivated in the Bahia State, Northeastern Brazil. Four different approaches were used to evaluate the digestion procedure ((i) desirability; (ii) multiple response; (iii) residual carbon content and (iv) residual acidity). The accuracy of the method of digestion was applied for the extraction of the studied elements in two certified reference materials (RM-Agro E1001a Brachiaria brizantha and NIST 1515 apple leaves). The limits of quantification of the method (µg g−1) were: Cr, 0.42; Cu, 0.69; Fe, 1.5; Mn, 0.14; Zn, 1.8; Ca, 29.0; K, 3.5; Mg, 1.9; P, 6.4; and S, 17. Two multivariate tools, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were efficient in the formation of groups, corresponding to the fruit parts. Thus, the peel and seed of Casearia fasciculata present potential to be used as mineral supplements in human nutrition.
DOI: 10.6084/m9.figshare.14303853.v1
title: Determination and Risk Assessment of Formaldehyde and Acetaldehyde in the Ambient Air of Gas Stations in Salvador, Bahia, Brazil

description: Formaldehyde (FA) and acetaldehyde (AA) were determined in the ambient air of five gas stations (GS) in the city of Salvador, Bahia State, Brazil, using three passive samplers exposed simultaneously for 8 h and analysis by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The concentration ranges found were 3.31-5.78 µg m−3 for FA and 10.5-28.2 µg m−3 for AA. These values were below the exposure limits recommended by national and international agencies for occupational environments, however, FA concentrations were above the more restrictive limit (3.30 µg m−3) stablished by Texas Commission on Environmental Quality (TCEQ) for long-term outdoor exposure. The lifetime cancer risks (LCR) found associated with the exposure of GS employees to these aldehydes over the 30-year period varied between 4.51 × 10−6-8.00 × 10−6 for FA and 2.46 × 10−6-6.60 × 10−6 for AA. These values are above the acceptable limit set by the USEPA (1.0 × 10−6), reinforcing the need for actions to minimize the occupational exposure, mainly to FA, which is associated with nasopharyngeal cancer.
DOI: 10.6084/m9.figshare.14303852.v1
title: Synthesis, Antileishmanial Activity and Spin Labeling EPR Studies of Novel β-Carboline-Oxazoline and β-Carboline-Dihydrooxazine Derivatives

description: A series of novel 1-(substituted-phenyl)-3-(4,5-dihydro-1,3-oxazol-2-yl)-9H-β-carboline (8a-8i) and 1-(substituted-phenyl)-3-(5,6-dihydro-4H-1,3-oxazin-2-yl)-9H-β-carboline (9a-9h) derivatives, as well as their respective N-(chloroalkyl)-1-(substituted-phenyl)-9H-β-carboline-3-carboxamide precursors (6a-6i and 7a-7h), were synthesized and evaluated for their in vitro antileishmanial activity against promastigote and intracellular amastigote forms of Leishmania amazonensis. Compounds 8d, 8i, 9e and 9h exhibited significant activity for both promastigote and amastigote forms, with IC50 (50% inhibitory concentration) values ranging from 2.9 to 23.0 µM. In addition, spin label electron paramagnetic resonance (EPR) spectroscopy studies were carried out for the most active compounds against L. amazonensis promastigotes. The studies indicated that the tested compounds cause strong stiffness in the parasite plasma membrane and are capable of inducing internal metalloproteins oxidation of the parasite, resulting in their cross-linking to skeletal proteins. Compounds 8d and 8i produced the largest effect, showing that the presence of oxazoline group at C-3 of β-carboline nucleus is important for antileishmanial activity.
DOI: 10.6084/m9.figshare.14303850.v1
title: Influence of the Capping Agent PVP of the Outer Layer of Pd Nanocubes Surface on the Catalytic Hydrogenation of Unsaturated C−C Bonds

description: The excess of capping agents used during the synthesis of nanoparticles is usually removed by solvent washing. The influence of the amount of polyvinylpyrrolidone (PVP) capping agent in the catalytic activity of palladium nanocubes was evaluated, after different numbers of washing cycles in the purification step performed after the syntheses of the nanoparticles. The effect of PVP amount on the hydrogenation of unsaturated carbon-carbon bonds was evaluated in terms of kinetic analysis and diffusion experiments. Five different catalysts were prepared utilizing the washing off procedure. All catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, small angle X-ray scattering spectroscopy and dynamic light scattering. The reaction presented strong influence by the amount of PVP, which was determined to be due to a balance between the amount of capping agent and the structure of the substrate.
DOI: 10.6084/m9.figshare.14303848.v1
title: Determination of Copper and Cadmium in Petroleum Produced Formation Water by Electrothermal Atomic Absorption Spectrometry after Cloud Point Extraction

description: Cloud point extraction (CPE) in association with graphite furnace atomic absorption spectrometry (GF AAS) was proposed for preconcentration and quantification of trace amounts of copper and cadmium in samples of saline produced formation water from petroleum exploration. The procedure was based on the formation of hydrophobic complexes of the analytes with 1,5-diphenylthiocarbazone (dithizone) in a micellar media of the surfactant (1,1,3,3-tetramethyl butyl) phenyl-polyethylene glycol (Triton X-114). Constrained mixture design was performed for the optimization of the proportions of the three solutions employed in the CPE: Triton X-114, dithizone, and buffer solution. Under the recommended conditions, the CPE GF AAS procedure allowed to obtain enrichment factors of 18 and 11 times, limits of quantification of 0.030 and 0.12 µg L-1 and precision, expressed as relative standard deviation (RSD, n = 8, 2.0 µg L-1), of 1.1 and 4.3% for copper and cadmium, respectively. The CPE GF AAS method was applied to the determination of copper and cadmium in samples of saline produced formation water from petroleum exploration, and its accuracy was accessed by analyzing certified reference material CASS-5 (Nearshore Seawater Reference Material for Trace Metals) from National Research Council (Canada).
DOI: 10.6084/m9.figshare.14303846.v1
title: Effects of Soil and Vineyard Characteristics on Volatile, Phenolic Composition and Sensory Profile of Cabernet Sauvignon Wines of Campanha Gaúcha

description: The influence of vineyard on wines was evaluated for the first time using a broader analytical approach: sensory analyses and several analytical techniques (gas chromatography-mass spectrometry (GC-MS), GC flame ionization detection (FID), GC-olfactometry-Osme technique (GC-O-Osme), GC × GC-MS), taking into account odoriferous compounds of Cabernet Sauvignon wines. Sensory attributes were correlated to the concentration of volatiles and also to favorable climate/solar exposition, less clayey/lower organic matter soil, and lower vegetative growth of one out of five vineyards, C1. Among 30 coelutions in GC-MS, 12 involved some of the odoriferous volatiles and GC × GC-MS was required to elucidate their identities. Higher concentrations of ethyl propanoate and diacetyl (related with red fruits/aromatic intensity) and of acetoin (aroma of dry fruits, but coeluted with octanal in first dimension (1D), which presents green odor) were found in C1 wine. It was also correlated with positive appearance attributes, gustatory persistence, body, smell and taste harmony, as well as with higher concentrations of phenolic acids, anthocyanins, flavonols, stilbenes, and flavanols.
DOI: 10.6084/m9.figshare.14303845.v1
title: Matrix Effects on the Degradation of Gemfibrozil, Hydrochlorothiazide, and Naproxen by Heterogeneous Photocatalysis

description: The degradation of a pharmaceutical mixture (gemfibrozil, hydrochlorothiazide and naproxen) by TiO2/UV-A in different aqueous matrices was evaluated. The matrix components affected the operational conditions, rate constants, and removal efficiency of the pharmaceuticals, as well as toxicity. For sewage treatment plant effluent, a TiO2 concentration three-fold higher (450 mg L−1) and an irradiation time 1.5-3 times longer were required to reach the same efficiency of degradation as the pharmaceuticals in deionized water and surface water matrices. An improvement in the rate constants and the removal efficiency of the pharmaceuticals was achieved by adding 6 mg L−1 of H2O2 and 150 mg L−1 of TiO2 in deionized water and surface water, but not in the sewage treatment plant effluent, due to the coupling of 450 mg L−1 of TiO2 and 50-200 mg L−1 of H2O2. Overall, TiO2/UV-A efficiently degraded all compounds, but an additional step is needed for the removal of residual toxicity.
DOI: 10.6084/m9.figshare.14303843.v1
title: Assessment of Atmospheric PM10 Pollution Levels and Chemical Composition in Urban Areas near the 2016 Olympic Game Arenas

description: Coarse particulate matter (PM10) concentrations and chemical composition were monitored from 2014 to 2017 at three sampling sites in the Metropolitan Region of Rio de Janeiro, namely Botafogo, Gávea, and Gericinó. All sites are located close to the 2016 Olympic Game arenas. The average annual PM10 concentrations were above the limits recommended by the World Health Organization (WHO) at all sampling sites. Of all the analyzed water-soluble ions, the highest concentrations were obtained for NO3-, SO42-, Cl- and Na+. Sulfate displayed a higher anthropic contribution (ca. 70%). Iron and copper were present in all samples, originated from soil resuspension and traffic (fuels and brakes, among others). Overall, civil works to restructure the city and the construction of the Olympic Game arenas increased PM10 and some of its constituent levels prior to 2016. After the Olympic Games, PM10 concentrations have decreased, due to governmental policies regarding traffic planning and civil work finalization.
DOI: 10.6084/m9.figshare.14303840.v1
title: Simultaneous Transfer of Na+, K+, and Fe2+ Ions During Salting of Precooked Mushroom (Agaricus bisporus): Mathematical Modeling, Optimization, and Experimental Validation

description: The champignon mushroom has no antinutritional factors that can affect iron bioavailability. It is considered a functional food and can provide health benefits by presenting bioactive components. The simultaneous transfer of Na+, K+ and Fe2+ in the pre-cooked mushroom (Agaricus bisporus) was modeled and simulated by the finite element method (FEM). The Biot number, cross and main diffusion coefficients were determined by the super modified simplex optimization method by minimizing the percentage errors. The errors between experimental and simulated data were 5.66% for NaCl, 5.36% for KCl and 8.26% for Fe2+ in the static brine and 3.11% for NaCl, 3.30% for KCl and 15.34% for Fe2+ in stirred brine. With the obtained model, it was possible to verify the influence of the film formed on the surface of the mushroom during the diffusion of ions, as well as the increase of ferrous ion adsorption when using the salting system with stirring.
DOI: 10.6084/m9.figshare.14303837.v1
title: Chemically-Activated Biochar from Ricinus communis L. Cake and Their Potential Applications for the Voltammetric Assessment of Some Relevant Environmental Pollutants

description: Biochar is a rich-carbon material highly functionalized, which allows the use as electrodes modifier for preconcentration and voltammetric determination of several species. This work describes a castor cake biochar production and chemical activation with different reaction conditions using HNO3 and/or H2O2. Biochar samples were characterized using scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman and zeta potential. Carbon paste modified electrodes (CPME) have been constructed using different biochar samples to evaluate the adsorptive capacity for the spontaneous preconcentration and voltammetric determination of Pb2+, Cd2+, Cu2+ and Ni2+ ions, paraquat and methyl parathion pesticides. The activation treatments promoted modifications in the elemental, morphological and structural biochar characteristics. Activated biochar CPMEs showed increase in the current signal around 15 and 2.5 times higher than unmodified and precursor biochar electrode, respectively. N2 sample (HNO3, 60 °C for 3.0 h) presented the better response signals for all compounds. This was attributed to the more effective surface oxidation, promoting a high porosity, acid character and amount of acid functional groups. Besides that, this greater analytical response allows the CPME-N2 application as a passive sampler for the voltammetric determination of inorganic and organic contaminants for environmental management in aqueous matrices.
DOI: 10.6084/m9.figshare.14303835.v1
title: Regenerated Cellulose Membrane from Peanut Shell for Biodiesel Purification

description: Biodiesel purification by water washing has been proved to be an unattractive process from an economic and environmental point of view. In this work, we propose the use of regenerated cellulose membranes from peanut shell as an alternative in the biodiesel purification. The preparation of the membranes was optimized from a central composite design, resulting in dense and non-porous membranes. However, in contact with biodiesel, the membranes undergo expansion due to the retention of methanol, water, and glycerol molecules, allowing the permeation of fatty acid methyl esters. The filtered biodiesel presents quality parameters, such as total ester content of 98.3 ± 1.4% and free glycerol content &lt; 0.02%, in agreement with the main regulatory agencies. The regenerated cellulose membranes from peanut shell are easily prepared, with high repeatability (relative standard deviation (RSD) &lt; 1.8%) and are presented as an economical and environmental solution for the biodiesel purification.
DOI: 10.6084/m9.figshare.14303833.v1
title: Evaluation of Carbon Nanotubes/Polyaniline Thin Films for Development of Electrochemical Sensors

description: Thin films of multiwalled carbon nanotubes/polyaniline nanocomposites (CNT/PAni) were synthesized through the liquid/liquid (L/L) interfacial route, deposited over glass substrates, and evaluated through cyclic voltammetry and amperometry as electrochemical sensor, using L-ascorbic acid as probe. Films with three different CNT/PAni ratios have been prepared. After the spectroscopic and morphological characterization, the electrochemical sensitivity towards L-ascorbic acid was evaluated and compared with similar sensors prepared from neat multiwalled carbon nanotubes (MWCNT) or neat polyaniline (PAni). The nanocomposite film that presented the best nanotube dispersion through the polymeric matrix presented the higher sensor sensibility, 0.237 µA (µmol L−1)−1 and a limit of detection (LOD) of 7.91 µmol L−1. These results evidenced a synergistic effect among the components, and the best response depended on strict control of the polyaniline matrix distribution surrounding the nanotubes.
DOI: 10.6084/m9.figshare.14303831.v1
title: An Alternative Spectrophotometric Determination of Carbaryl Insecticide Residues in Water Samples Using the Cerium-Catalyzed Belousov-Zhabotinsky Oscillating Reaction

description: An alternative approach for carbaryl determination based on the change in the oscillation period of the Belousov-Zhabotinsky (BZ) reaction under the addition of carbaryl is demonstrated. The oscillations were observed by spectrophotometric measurement at 320 nm, corresponding to the maximum absorption wavelength of cerium(IV) catalyst. The oscillation periods increase with the carbaryl concentrations, which can be discussed based on the Field-Körös-Noyes (FKN) mechanism. The increase of oscillation periods is proportional to the concentration of carbaryl in the range of 0.1-200 mg L-1 with the regression coefficient of 0.9938. The limits of detection and quantification were 0.044 and 0.147 mg L-1, respectively. The precisions in terms of intra-day and inter-day measurements were efficient with relative standard deviation (RSD) lower than 2.1%. Accuracy of carbaryl in different water samples was obtained with high recoveries in the range of 94-106% and also comparable to the results of high performance liquid chromatography (HPLC) analysis. The proposed method is precise, cost-effective and can be alternatively employed for the screening and determination of carbaryl residues in water samples.
DOI: 10.6084/m9.figshare.14303828.v1
title: Variability of the Volatile Organic Compounds of Achillea millefolium L. According to the Collection Time, Type of Polyethylene Packaging and Storage Period

description: The collection time could be an important target for optimizing technological processes in obtaining essential oils of interest to agribusiness. The objective of this study was to distinguish the time for the collecting of Achillea millefolium L. leaves, which provides the highest yield and quality of the essential oil. Also, identify the type of polyethylene packaging and leaf storage period during the one-year period that would maintain the essential oil characteristics. Gas chromatography-mass spectrometry and chemometric studies were performed into two steps trial to detect changes in chemical profile induced by different conditions. First, an analysis of the leaf collection time was performed using chromatographic data from six different gathering times throughout the day. After determining the best time to collect from the leaves, the essential oil was extracted in five storage periods over a year. The highest oil content was observed in leaves harvested between 11 and 15 h, with a maximum of 39 min after 13 h. Therefore, it is recommended to perform extraction in the early afternoon. There was no significant statistical differentiation related to polyethylene packages. In addition, it is recommended that the essential oil can be stored without significant changes for up to six months.