ANÁLISE DA VEGETAÇÃO RIPÁRIA EM BACIA HIDROGRÁFICA UTILIZANDO ÍNDICE DE VEGETAÇÃO NORMALIZADA (NDVI) NO MUNICÍPIO DE MARINGÁ-PR / ANALYSIS OF RIPARIAN VEGETATION IN A WATERSHED USING NDVI INDEX IN MARINGA-PR

doi: 10.12957/geouerj.2017.26737 The Normalized Difference Vegetation Index (NDVI) is obtained from satellite digital image processing, based on different reflectances that plants emit in different solar radiation. The aim of this study was the comparative analysis of different NDVI values found in riparian vegetation of a watershed, located in Maringá-PR, from different periods of 2015. The satellite images were obtained from the United States Geological Survey, being the Landsat 8 scene 223-076 used. The NDVI was calculated in QGIS 2.8.8. In the areas closest to the rivers, was verified the highest NDVI values, which may be related to water availability and size of vegetation. The data, along with the Kruskal-Wallis and similarity tests indicated higher similarity between the months of the summer - autumn, and winter - spring. There was no clear relation between the behavior of the variation of NDVI with precipitation, evapotranspiration and average temperature; however, this may be explained by the delay between the canopy to environmental changes. Such behavior could be understood with a longer data period, thus, the use of historical series is suggested for future works

Physico-chemical and electrostatic surface characterisation of mica mineral and its applicability on the adsorption of Safranin Orange and Reactive Black 5 dyes

The combined approach of specific surface area (SSA), porosity, microprobe analysis (EMPA), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with EDX and infrared spectroscopy (FTIR) provided the mica mineral physico-chemical and morphological characterisation. The electrostatic surface properties were assessed through the determination of the Point of Zero Charge (pHPZC) by the drift method and the electrokinetic mica mineral features represented by the Isoelectric Point (pHIEP) which was carried out through zeta potential measurements. Adsorption tests were performed to correlate the surface charge behaviour of the mica mineral and its influence on the adsorption efficiency of two different dyes, namely: Safranin Orange (SO), as a cationic dye and Reactive Black 5 (RB5), as an anionic dye. The higher adsorption capacity SO dye was observed at pH 9 and achieved almost 83% of removal, while RB5 dye adsorption on mica surface had the highest result, about 45% of removal efficiency, on pH of 3. In both cases, the main mechanism identified that drove this results is the electrostatic force of attraction between the adsorbent edge surface charge (pHdependent) and the ionic nature (anionic or cationic) of the pollutant dyes particles. The preliminary adsorption experiments demonstrated that the raw grounded mica mineral has a greater potential associated with its application on cationic dye removal in wastewater. The present study aimed to detail the main characteristics of the mica mineral in order to evaluate the potential use of such mineral residues in the removal efficiency of contaminated wastewaterinfo:eu-repo/semantics/publishedVersio

Synergistic Mechanism of Photocatalysis and Photo-Fenton by Manganese Ferrite and Graphene Nanocomposite Supported on Wood Ash with Real Sunlight Irradiation

The present research aimed to evaluate the photocatalytic activity of reduced graphene oxide and manganese ferrite nanocomposite supported on eucalyptus wood ash waste (WA) from industrial boilers, for the decolorization of methylene blue (MB) solutions, using sunlight as an irradiation source. For this, the photocatalyst named MnFe2O4-G@WA was synthesized by a solvothermal method and characterized by analyzes of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller and zeta potential. Firstly, the photocatalyst was evaluated for photocatalytic decolorization of MB under different reaction conditions. Then, the influence of pH, photocatalyst dose and H2O2 was evaluated. MnFe2O4-G@WA showed 94% of efficiency for photocatalytic decolorization of MB under operating conditions of solar irradiation, 0.25 g/L of catalyst, 300 mg/L of H2O2. The proposed degradation reaction mechanism suggested that the photodegradation of MB was through a synergistic mechanism of photocatalysis and photo-Fenton reactions, with the combined action of the three materials used. The data adjusted to the first order kinetics from the Langmuir–Hinshelwood model. In addition, MnFe2O4-G@WA showed high stability, maintaining its efficiency above 90% after 5 cycles. The results indicated that the nanophotocatalyst is a potential technology for the decolorization of MB solutions