Browsing by Author "Silva, Heriveltom Morais da"

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    Anthocyanin immobilization in carboxymethylcellulose/starch films : a sustainable sensor for the detection of Al(III) ions in aqueous matrices.
    (2020) Silva, Heriveltom Morais da; Mageste, Aparecida Barbosa; Silva, Sílvia Juliana Barros e; Ferreira, Guilherme Max Dias; Ferreira, Gabriel Max Dias
    A robust and sustainable sensor for the detection of Al(III) ions in water was developed by immobilization of anthocyanin (AN) from black rice in a film formed by carboxymethylcellulose (CMC) and starch. Characterization of the films was performed using solubility, thickness, FTIR, and mechanical analysis. The film exhibited an irreversible color change from red to purple in response to the presence of Al(III). The best colorimetric response of the sensor was observed at pH 4.5 and a time of 60 min, achieving the detection of 3 mg L−1 of Al(III). For concentrations higher than 5 mg L−1, the sensor response time decreased to 20 min. The minimum Al(III) concentration detected with the naked eye was lower than the maximum permissible concentrations in aqueous effluents according to different legislations, indicating the potential of this study to develop sensors for the detection of Al(III).
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    Use of aqueous two-phase PEG-salt systems for the removal of anionic surfactant from effluents.
    (2017) Murari, Gabriella Frade; Penido, Jussara Alves; Silva, Heriveltom Morais da; Baeta, Bruno Eduardo Lobo; Aquino, Sergio Francisco de; Lemos, Leandro Rodrigues de; Rodrigues, Guilherme Dias; Mageste, Aparecida Barbosa
    Linear alkylbenzene sulfonates (LAS) are synthetic anionic surfactants that are extensively used in many industries. As a result, large volumes of effluents containing high levels of these compounds are discharged into water bodies, causing risks to aquatic flora and fauna. Then, there is a need for environmentally safe and economically viable technologies for the removal of LAS from aqueous matrices. The present work evaluates the use of aqueous two-phase systems (ATPS) composed of PEG and sulfate salts for this purpose, considering the effects of tie line length (TLL), molar mass of polymer, and type of cation-forming salt on the partitioning behavior of LAS. All the LAS partition coefficient (KLAS) values were greater than unity, and the LAS extraction efficiencies (%ELAS) were higher than 97%. The system consisting of PEG 1500 þ (NH4)2SO4 þ H2O provided the highest KLAS (1083.34) and %ELAS (99.9%), indicating that the method provided good extraction of LAS to the top phase. This system was applied using a real effluent sample in laboratory-scale experiments as well as in bench-scale batch trials. The results obtained at the laboratory scale showed %ELAS values greater than 98%, while the best KLAS value obtained in the batch experiments was 8.50 (±1.75) (%ELAS ¼ 78.17%). These values demonstrated the potential of ATPS for the removal of LAS from industrial effluents.