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Your search keyword '"Ribeiro, Alexandra B."' showing total 353 results
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353 results on '"Ribeiro, Alexandra B."'

2. Emerging organic contaminants in wastewater: Understanding electrochemical reactors for triclosan and its by-products degradation

Author

Magro, Catia, Mateus, Eduardo P., Paz-Garcia, Juan M., and Ribeiro, Alexandra B.

Subjects
Physics - Chemical Physics
Abstract

Degradation technologies applied to emerging organic contaminants from human activities are one of the major water challenges in the contamination legacy. Triclosan is an emerging contaminant, commonly used as antibacterial agent in personal care products. Triclosan is stable, lipophilic and it is proved to have ecotoxicologic effects in organics. This induces great concern since its elimination in wastewater treatment plants is not efficient and its by-products (e.g. methyl-triclosan, 2,4-dichlorophenol or 2,4,6-trichlorophenol) are even more hazardous to several environmental compartments. This work provides understanding of two different electrochemical reactors for the degradation of triclosan and its derivative by-products in effluent. A batch reactor and a flow reactor (mimicking a secondary settling tank in a wastewater treatment plant) were tested with two different working anodes: Ti/MMO and Nb/BDD. The degradation efficiency and kinetics were evaluated to find the best combination of current density, electrodes and set-up design. For both reactors the best electrode combination was achieved with Ti/MMO as anode. The batch reactor at 7 mA/cm2 during 4 h attained degradation rates below the detection limit for triclosan and 2,4,6-trichlorophenol and, 94% and 43% for 2,4-dichlorophenol and methyl triclosan, respectively. The flow reactor obtained, in approximately 1 h, degradation efficiencies between 41% and 87% for the four contaminants. This study suggests an alternative technology for emerging organic contaminants degradation, since the combination of a low current density with the flow and matrix induced disturbance increases and speeds up the compounds elimination in a real environmental matrix.

Published
2020
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6. Simultaneous Determination of Glyphosate and 13 Multiclass Pesticides in Agricultural Soil by Direct-Immersion SPME Followed by Solid–Liquid Extraction.

Author

Brinco, João, Guedes, Paula, da Silva, Marco Gomes, Mateus, Eduardo P., and Ribeiro, Alexandra B.

Abstract

A new method is presented for the simultaneous determination of 13 multiclass pesticides along with glyphosate. The multiclass pesticides were extracted by creating a soil slurry with 2% ethanol in water (v/v), and then, applying direct-immersion solid-phase microextraction (DI-SPME) with a new type of semi-disposable SPME fiber configuration called LC-Tips. The fibers were then retroextracted to ethanol, and aqueous ammonia was added to the slurry to extract glyphosate. Derivatization of the glyphosate extract was accomplished with a mixture of trifluoroacetic anhydride and trifluoroethanol, after which the reaction mixture was dried and resuspended with the SPME ethanol extract. To this, a mixture of analyte protectants was added, and it was analyzed by GC-MS/MS in multiple-reaction-monitoring mode. All analytes showed a coefficient of determination greater than 0.95 in the 0.1–100 µg/kg calibrated range, and the limits of detection were between 0.1 and 1 µg/kg, except for glyphosate, which was 0.01 µg/kg. The method shows relatively high replicate relative standard deviation (as much as 37% for five extractions at 20 µg/kg), but the isotopically labeled internal standard was effective at mitigating this effect for some analytes. [ABSTRACT FROM AUTHOR]

Published
2024
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49. the technological innovation patented review

Author

Beolchini, F., Hekeu, M., Amato, A., Becci, A., Ribeiro, Alexandra B., Mateus, Eduardo P., Dell’anno, A., DCEA - Departamento de Ciências e Engenharia do Ambiente, and CENSE - Centro de Investigação em Ambiente e Sustentabilidade

Abstract

Part of the work has been realized thanks to staf exchange within the H2020-MSCA-RISE-2017 project e.THROUGH. Sediment contamination with polycyclic aromatic hydrocarbons represents a major environmental concern worldwide. The different remediation strategies proposed are mainly based on physico-chemical and biological approaches. Physico-chemical methods (also referred to as conventional methods), although more efficient in several cases, are considered as less sustainable as a result of their higher environmental and economic costs. Biotechnological methods on the other hand, which make use of microorganisms and/or their metabolic products, have received increased attention as a more environment friendly and less costly alternative, although usually more time consuming. The various biotechnological approaches developed and patented on bioremediation of sediments polluted with polycyclic aromatic hydrocarbons are presented in this review, as well as some soil bioremediation methods considered applicable to sediments. Patents on sediment microbial fuel cells and other electrokinetic approaches are also included as considerable advances have been made in this field. Over 150 patents dating from 1995 to 2019 were collected from Espacenet platform, a worldwide patent database and considered in the present review. Overall, this review highlighting strengths and weaknesses of the various biotechnological approaches developed and patented, so far, can be useful to address further studies to improve bioremediation performance and can represent a benchmark of information for bioremediation companies to identify and explore the most promising field applicable approaches. authorsversion epub_ahead_of_print

Published
2021

50. Electrochemical Advanced Oxidation as Onsite Treatment

Author

Ferreira, Ana Rita, Guedes, Paula, Mateus, Eduardo P., Ribeiro, Alexandra B., Couto, Nazaré, CENSE - Centro de Investigação em Ambiente e Sustentabilidade, DCEA - Departamento de Ciências e Engenharia do Ambiente, and Instituto de Tecnologia Química e Biológica António Xavier (ITQB)

Subjects
advanced oxidation process, Chemistry(all), SDG 3 - Good Health and Well-being, effluent reuse, pharmaceuticals, micropollutants, electrocatalytic material
Abstract

Emerging organic contaminants are one of the main threats to the environment and society. The primary source of these contaminants in the environment is wastewater treatment plants (WWTPs) that cannot eliminate all of these compounds. Pharmaceutically active compounds (PhACs) deserve special attention as new substances are constantly being developed, and the number of these compounds that reach consumers is increasing. The consequences of PhACs to human health are not yet subjected to regulatory criteria or norms; nevertheless, chronic toxicity in biodiversity has already been reported. In response to global environmental concerns, there has been increasing interest in sustainable solutions to remove these compounds from effluent in WWTPs. Electrochemical technologies developed for effluent treatment were designed to promote PhAC degradation and safe effluent discharge. Understanding the relationship between different anode characteristics and electrochemical oxidation performance is essential for developing a cost‐efficient technology to remove contaminants from wastewater. In this context, the performance of graphite and platinized electrodes were compared in the electrochemical oxidation of selected emerging organic contaminants in a recirculating flow reactor. proof epub_ahead_of_print

Published
2021

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