Analysis of 17- β -estradiol and 17- α -ethinylestradiol in biological and environmental matrices — A review

The estrogens 17-β-estradiol (E2) and 17-α-ethinylestradiol (EE2) are reported as highly endocrine-disrupting agents, being recently included in an EU watch list regarding emerging aquatic pollutants. Therefore, the monitoring of these chemicals in the different environmental compartments assumes great importance. Moreover, due to the possible adverse effects on living beings, their occurrence on animal tissues and fluids must also be addressed. In recent years, a significant number of studies have described and proposed different analytical methodologies to detect and/or quantify E2 and EE2 mostly in environmental aqueous samples, including sludge and sediments and also in biological matrices such as plasma and tissues. Taking into account the complexity of real matrices and that both estrogens are generally present at trace levels, the development of accurate and reliable techniques for their determination can be quite a challenge. The present review aims at describing the main characteristics of the analytical methods recently used for E2 and EE2 determination in environmental and biological samples. The steps for sample preparation such as analytes extraction, preconcentration and clean-up are discussed and the instrumental based analytical techniques are compared. Furthermore, the application of biological tools to determine the total estrogenicity of environmental samples, as well as their potential combination with instrumental analyses, is highlighted.info:eu-repo/semantics/publishedVersio

Enhanced performance of cobalt ferrite encapsulated in graphitic shell by means of AC magnetically activated catalytic wet peroxide oxidation of 4-nitrophenol

Here we report preliminary catalytic wet peroxide oxidation (CWPO) experiments performed in the presence of an alternating current (AC) magnetic field. One ferromagnetic graphitic nanocomposite - composed by a cobalt ferrite core and a graphitic shell (CoFe2O4/MGNC), was employed in the process, here named magnetically activated catalytic wet peroxide oxidation (MA-CWPO). An aqueous solution containing 5.0 g L-1 of 4-nitrophenol (4-NP) to simulate a high strength polluted stream was used as model system. The experiments were performed at room temperature and atmospheric pressure, with stoichiometric amount of hydrogen peroxide (H2O2), pH = 3 and CoFe2O4/MGNC catalyst load = 5.0 g L-1 (corresponding to a 4-NP/CoFe2O4 mass ratio of 6.9, as CoFe2O4 accounts for 14.4 wt% of CoFe2O4/MGNC). It was shown that the performance of CWPO is enhanced upon application of an AC magnetic field (frequency of 533.9 kHz and magnitude of 240 G). As a result, high 4-NP mineralization was obtained by MA-CWPO (as reflected by a total organic carbon abatement of 79% after 4 h of reaction, instead of 39% in the absence of a magnetic field). This positive effect was ascribed to the localised increase of CoFe2O4/MGNC surface temperature resulting from heat release upon exposure of the nanoparticulated catalyst to an AC magnetic field, which accelerates the catalytic decomposition of H2O2 via hydroxyl radicals (HO center dot) formation

UV-A activation of peroxymonosulfate for the removal of micropollutants from secondary treated wastewater

The occurrence of micropollutants (MPs) in the aquatic environment poses a threat to the environment and to the human health. The application of sulfate radical-based advanced oxidation processes (SR-AOPs) to eliminate these contaminants has attracted attention in recent years. In this work, the simultaneous degradation of 20 multi-class MPs (classified into 5 main categories, namely antibiotics, beta-blockers, other pharmaceuticals, pesticides, and herbicides) was evaluated for the first time in secondary treated wastewater, by activating peroxymonosulfate (PMS) with UV-A radiation, without any pH adjustment or iron addition. The optimal PMS concentration to remove the spiked target MPs (100 mu g L-1) from wastewater was 0.1 mM, leading to an average degradation of 80% after 60 min, with most of the elimination occurring during the first 5 min. Synergies between radiation and the oxidant were demonstrated and quantified, with an average extent of synergy of 69.1%. The optimized treatment was then tested using non-spiked wastewater, in which 12 out of the 20 target contaminants were detected. Among these, 7 were degraded at some extent, varying from 10.7% (acetamiprid) to 94.4% (ofloxacin), the lower removals being attributed to the quite inferior ratio of MPs to natural organic matter. Phytotoxicity tests carried out with the wastewater before and after photo-activated PMS oxidation revealed a decrease in the toxicity and that the plants were able to grow in the presence of the treated water. Therefore, despite the low degradation rates obtained for some MPs, the treatment effectively reduces the toxicity of the matrix, making the water safer for reuse

Pd and Pd-Cu supported on different carbon materials and immobilized as flow-through catalytic membranes for the chemical reduction of NO3, NO2-and BrO3- in drinking water treatment

Powdered catalysts are commonly used in lab-scale tests for the catalytic reduction of oxoanions in drinking water, but their powder nature limits their application at full scale. In this work, Pd and Pd-Cu catalysts (5% wt.) supported on carbon materials with different structural properties, in powder form, were used to prepare catalytic membranes that were tested in a reactor with flow-through configuration (FTCMR) to study their performance in the reduction of NO3-, NO2- and BrO3-. Pd catalytic membranes showed high activity in the reduction of NO2-, being the selectivity to NH4+ lower than 2% at 80% NO2- conversion in all cases. In BrO3- reduction, they exhibited a wide range of conversions being the catalyst supported on materials with high conductivity the most active ones, which may be ascribed to the charge distribution at the metal-carbon interface. NO3- reduction using Pd-Cu catalytic membranes showed that catalysts supported on materials with small nanoparticle size and low electrical conductivity exhibited higher selectivity to NH4+. FTCMR led to a good control of H2 transfer and availability in the active sites, facilitating the tuning of H2 availability conditions to preserve the activity, while maintaining/diminishing selectivity to NH4+. In simultaneous oxoanions reduction tests, NO3- reduction was inhibited by Br species, probably by affection of the Pd-Cu redox cycle. This fact could be crucial to the future development of drinking water treatment processes, as conditions the order of the disinfection and NO3- reduction stepsThe authors greatly appreciate the support from Spanish Agencia Estatal de Investigacion ´ (AEI, RTI2018–098431-BI00). Adrian ´ Marí thanks the Spanish AEI for a research grant (PRE-2019-088601). This work was also financially supported by: LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM) and funded by national funds through FCT/MCTES (PIDDAC), and project NORTE01–0145-FEDER-000069 (Healthy Waters) co-funded by European Regional Development Fund (ERDF), through North Portugal Regional Operational Program (NORTE2020), under the PORTUGAL 2020 Partnership Agreemen

Tuning graphitic carbon nitride (g-C3N4) electrocatalysts for efficient oxygen evolution reaction (OER)

Nowadays, energy conversion and storage technologies are essential research topics due to the necessity of more sustainable processes. Specifically, water splitting is highly affected by slow kinetics and limited knowledge of the oxygen evolution reaction (OER). This work envisages the preparation of graphitic carbon nitride (g-C3N4) electrocatalysts for efficient OER by a facile one-pot method. The impact of the preparation temperature (450–650 ◦C) of g-C3N4 was assessed for the first time on water splitting processes and explained by different characterisation techniques. The unique crystal structure, surface chemistry, and electronic properties of the material prepared at 550 ◦C lead to a remarkable OER efficiency, with an overpotential of 355 mV at 10 mA cm− 2 and a Tafel slope of 46.8 mV dec− 1. Interestingly, three major differences were observed when comparing the material prepared at 550 ◦C with those obtained at other temperatures: the reduced structural distortion, the superior composition in oxygen and the presence of terminal functional groups. Also, compared to other metalfree g-C3N4 electrocatalysts reported in the literature, we achieved lower Tafel slope values without additional post-treatments or co-catalysts. Hence, for the first time a metal-free catalyst defeats benchmark IrO2. The prepared electrodes were stable for up to 45 h, even when increasing the applied current density to 100 mA cm− 2 for 15 h. Thus, this work provides a simple route for the fabrication of highly-efficient and long-lasting electrocatalysts for a remarkable OER performance.Agencia Estatal de Investigación | Ref. PID2020-113667 GB-I00Fundação para a Ciência e a Tecnologia | Ref. UIDB/50020/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/50020/2020Xunta de Galicia | Ref. ED481D-2023/015Universidade de Vigo/CISU