Influence of the doping level of boron-doped diamond anodes on the removal of penicillin G from urine matrixes

The objective of this study is to understand the influence of the characteristics of boron-doped diamond anodes on the degradation of Penicillin G contained in urine. Therefore, five commercial BDD anodes with different boron doping levels (100 ppm - 8000 ppm) were studied. These electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and electrolysis. The boron doping was found to correlate well with the electrochemical properties of the electrodes, and results indicate a different behavior in drug degradation. The improvement in the toxicity and the reduction of the antibiotic effect of urine were the most innovative inputs monitored. For this, the concentration of Penicillin G, the toxicity toward Vibrio fisheri, and the antibiotic effect in Enterococcus faecalis were monitored. The best results were found for the BDD with a boron content of 200 ppm, capable of removing 100% of the antibiotic, reducing toxicity by 90%, and eradicating the antibiotic effect. These results indicate that low doping levels are more efficient for urine removal by anodic oxidation

Improving biodegradability of clopyralid wastes by photoelectrolysis: The role of the anode material

In this work, the removal of the non-readily biodegradable herbicide clopyralid by electrochemical (EC) and photoelectrochemical (PhEC) oxidation with different anode materials were conducted looking to improve not only its oxidation but also its biodegradability. First, in order to find out optimal conditions, it was carried out EC and PhEC degradations in chloride medium, at current densities ranging from 30 to 100 mA cm−2 during 1 h (0.8–2.7 A h L−1), using as anodes MMO-RuO2TiO2, MMO-RuO2IrO2, MMO-IrO2Ta2O5 and boron-doped diamond (BDD). Results show better efficiencies on clopyralid removal for MMO-RuO2IrO2 and BDD anodes at lower current densities. Then, the influence of all anodes on clopyralid transformation was evaluated, extending the electrolysis and photoelectrolysis for 8 h applying 30 mA cm−2 (6.4 A h cm−3). At these conditions, better outcomes are observed for PhEC degradation, where complete pollutant removal is attained for BDD anode and 88.7% for MMO-RuO2IrO2, while COD removal is 47.7% for MMO and 43.1% for BDD anode. Then, short-term biodegradability tests, conducted for EC and PhEC processes, pointed out that MMO-RuO2TiO2 is the most promising anode material, being capable of improving biodegradability in 48.2% and 53% for EC and PhEC degradation, respectively. The toxicity of treated solutions using MMO-RuO2TiO2 and BDD anodes in both EC and PhEC degradation were compared, employing the inhibitory effect in the bioluminescence of marine bacteria Vibrio Fisheri. Toxicity assessments show that toxicity significantly reduces by using the MMO-RuO2TiO2 in NaCl and Na2SO4 medium for both processes. Finally, this study demonstrates that photoelectrolysis with MMO anodes was the most effective strategy in order to increase biodegradability in chloride media, as well as to reduce the toxicity of the treated waste

Electrochemical systems equipped with 2D and 3D microwave-made anodes for the highly efficient degradation of antibiotics in urine

This work focuses on the importance of choosing a suitable electrochemical cell to remove antibiotics from urines. For this purpose, we investigate the use of two electrochemical cells for electrolysis and photo-electrolysis of urine polluted with a mixture of Penicillin G, Meropenem, and Chloramphenicol. The two reactors studied were a conventional flow pass electrochemical cell (E-cell) and a microfluidic flow-through reactor (MF-Reactor). Both reactors are equipped with a mixed metal oxide anode (MMO-RuO2IrO2) produced by hybrid heating using microwaves. The MMO coating was deposited on a Ti plate for the E-cell (2-D electrode) and on a Ti foam for the MF-Reactor (3-D electrode). Results demonstrate that the MF-Reactor stands out to reduce two important factors in electrochemical oxidation, the ohmic resistance associated with the microfluidic concept and the mass transfer limitations associated with the flow-through configuration. Moreover, it allows operating at a lower effective current density because of its larger active anodic surface area. Photo-electrolysis results in faster removal of all antibiotics studied in the MF-Reactor and E-cell, compared to the single electrolysis, thereby highlighting the significance of UV light-mediated electrochemical oxidation processes. This work highlights that despite the large number of papers focused on the selection of suitable electrodes for the electrochemical treatment of different types of wastes, the choice of the electrochemical cell can be even more important than the selection of those electrode materials, and it demonstrates that even using the same coating as the anode, highly different outcomes can be reached.Este trabajo se centra en la importancia de elegir una celda electroquímica adecuada para eliminar los antibióticos de las orinas. Para ello, investigamos el uso de dos celdas electroquímicas para la electrólisis y fotoelectrólisis de orina contaminada con una mezcla de Penicilina G, Meropenem y Cloranfenicol. Los dos reactores estudiados fueron una celda electroquímica de paso de flujo convencional (celda E) y un reactor de flujo continuo microfluídico (reactor MF). Ambos reactores están equipados con un ánodo de óxido metálico mixto (MMO-RuO 2 IrO 2) producido por calentamiento híbrido usando microondas. El recubrimiento de MMO se depositó en una placa de Ti para la celda E (electrodo 2D) y en una espuma de Ti para el reactor MF (electrodo 3D). Los resultados demuestran que el MF-Reactor se destaca por reducir dos factores importantes en la oxidación electroquímica, la resistencia óhmica asociada con el concepto de microfluidos y las limitaciones de transferencia de masa asociadas con la configuración de flujo continuo. Además, permite operar a una menor densidad de corriente efectiva debido a su mayor área de superficie anódica activa. La fotoelectrólisis da como resultado una eliminación más rápida de todos los antibióticos estudiados en el reactor MF y la celda E, en comparación con la electrólisis única, lo que destaca la importancia de los procesos de oxidación electroquímica mediados por luz ultravioleta

Microwave synthesis of Ti/(RuO2)0.5(IrO2)0.5 anodes: Improved electrochemical properties and stability

The efficiency of electrochemical technology in treating water contaminated by complex organic pollutants has been widely investigated. Notwithstanding, it is still necessary to develop technologies capable of producing efficient and economically viable electrodes. In this context, the electrochemical oxidation using mixed metal oxide (MMO) anodes is a promisor alternative for wastewater treatment. However, the production of these anodes through thermal decomposition in electric furnaces demands a lot of production time. Here, we report an innovative method based on hybrid microwave irradiation to produce MMO anodes of Ti/(RuO2)0.5(IrO2)0.5 composition. The developed method uses simple apparatus and is faster than other conventional methods, thus decreasing the production costs. The anodes prepared at different calcination temperatures (300, 350, and 400 °C) using microwaves irradiation were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, cyclic voltammetry, electrochemical impedance spectroscopy, and accelerated service life tests. Besides, the results were compared with those obtained using the conventional heating method. The microwave-produced anodes calcined at 350 °C have the longest service lifetime, which is estimated as 15 years, which is 3.5-fold more than the conventionally made anodes. In addition, this anode has improved electrochemical performance when compared with the conventionally prepared anodes, showing the highest voltammetric charge (1.6-fold). Moreover, this anode removes 100% of color and 64% of TOC after 60 min of electrolysis of the model molecule methylene blue dye. Therefore, the developed method allows for producing materials with improved electrocatalytic properties and enhanced stability at short synthesis times

Síntese de ánodos de misturas de óxidos metálicos assistida por micro-ondas para degradaçao de compostos orgánicos

Los ánodos de óxido de metal mixto (MOM) son materiales prometedores en tecnologías electroquímicas. En esta tesis se sintetizaron ánodos MOM de composición Ti/Ru0.5Ir0.5O2 mediante calentamiento por microondas, donde se optimizó la temperatura de síntesis, obteniendo alta actividad electrocatalítica y estabilidad física de las películas depositadas, en un proceso rápido y bajo consumo energético. Los ánodos preparados se caracterizaron mediante técnicas de caracterización física como difractometría de rayos X, microscopía electrónica de barrido, espectroscopía de rayos X de energía dispersiva y de rayos X y fotoelectrones electroquímicos (voltamperometría cíclica y lineal, capacitancia, espectroscopía de impedancia electroquímica y pruebas de estabilidad) y finalmente aplicado a la degradación de un contaminante modelo (colorante azul de metileno). Posteriormente, se seleccionó el ánodo Ti/Ru0.5Ir0.5O2 sintetizado a 350 ºC para evaluar su desempeño en diferentes procesos oxidativos electroquímicos avanzados en una matriz compleja (orina). Para ello, el ánodo se aplicó en procesos de oxidación electroquímica, fotoelectroquímica, Fenton, electro-Fenton y fotoelectro- Fenton para la degradación de efluentes sintéticos hospitalarios. Todos los experimentos realizados en este paso se compararon con un electrodo de diamante dopado con boro (DDB) comercial. Se observó que la combinación de irradiación UVC y el proceso electroquímico utilizando el ánodo MMO tiene mayor actividad electrocatalítica que la obtenida utilizando un ánodo DDB y un efecto sinérgico del 420%. En los procesos Fenton, electro-Fenton y fotoelectro-Fenton, el ánodo MOM demostró ser tan eficiente como el electrodo DDB, tanto para la remoción de penicilina G como para la reducción de toxicidad y actividad antibiótica. Finalmente, se varió la configuración del sistema de tratamiento de efluentes (celda discontinua o reactor microfluídico a través de los electrodos) y el tamaño del MMO (3,4 o 66 cm2). Por tanto, el reactor de microfluidos demostró ser más eficaz que la celda discontinua en la eliminación de antibióticos de una orina polimedicada y la ampliación se llevó a cabo de forma eficaz. Así, los resultados obtenidos en esta tesis son importantes porque muestran que los ánodos fueron producidos a través de un nuevo método de síntesis fácil y rápida, obteniendo ánodos con altísima eficiencia catalítica, los cuales se muestran prometedores para su aplicación en el tratamiento de diferentes tipos de efluentes y matrices

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora