BUSCADOR RECOLECTA

[EN] The increase in the consumption of pharmaceutical compounds has caused the increment of their presence in different body waters. beta-blockers are one of the most dangerous even at low concentrations (ng L-1). Anodic oxidation with a boron-doped diamond (BDD) anode presents good results to remove these compounds. However, since this anode is expensive, some cheaper materials are under study. In this work, Sbdoped SnO2 ceramic anodes (BCE) coated with Zn or Cd ferrites, in order to provide photocatalytic properties, have been applied to the degradation of the Atenolol (ATL) beta-blocker. Increasing the applied current increased ATL degradation and mineralization but caused a decrease in mineralization current efficiency (MCE) and an increase in energy consumption (ETOC). Additionally, light irradiation enhanced the ATL mineralization rate between 10% and 20% for both ferrites, although this increase was higher for the cadmium ferrite one. Finally, when the ferrites were compared with BDD and BCE anodes, the oxidizing power of the different anodic materials can be ordered as follows BDD > Cd-Fe > Zn-Fe > BCE. Therefore, both ferrites improved the BCE performance but only the cadmium one appeared as an alternative to the BDD, especially for MCE and ETOC, reaching values of 15% and 0.5 kWh gTOC-1, respectively., The authors want to show their gratitude to the Ministerio de Economia y Competitividad (Spain) and the Fondo Europeo de Desarrollo Regional (FEDER) funds that financially support the pro-ject RTI2018-101341-B-C21.

[EN] Advanced Oxidation Processes have been proven to be an efficient way to remove organic pollutants from wastewaters. In this work, a ceramic electrode of Sb-SnO2 (BCE) with a layer of the photocatalytic material
BiFeO3 (BFO-BCE), has been characterized electrochemically and further tested for norfloxacin photoelectrooxidation in the presence and absence of light. The electrode photoactivity was highly enhanced thanks to the presence of BiFeO3, as confirmed by Linear Sweep Voltammetry, chronoamperometry and potentiometry, and Electrochemical Impedance Spectroscopy. Additionally, working in galvanostatic mode, a high mineralization
of norfloxacin was achieved after 240 min, reaching 62% at 25 mA cm 2 under light conditions. This value is comparatively higher than the 40% achieved with the BCE. The oxidation byproducts were followed by ionic chromatography and HPLC analysis, which also allowed us to propose an oxidation pathway of the norfloxacin molecule. Finally, some indicators of the reactor performance such as the Mineralization Current Efficiency and the specific energy consumption were analyzed, revealing that lower current densities (8.3 mA cm -2) led to higher current efficiencies, and that light improved both the current efficiency and energy consumption., The authors thank the financial support through the project RTI2018-101341-B-C21 funded by MCIN/AEI/10.13039/501100011033/ (Spain) and by FEDER A way of making Europe and AICO/2021/128 funded by Generalitat Valenciana.

[EN] This dataset contains the evolution with time of the following measured variables: relative Norfloxacin concentration, relative total organic carbon Concentration and cell potential These variables was obtained for 3 different anodic materials, CuO (ceramic anode with Cupper as sintering aid), BDD and BCE (basic ceramic electrode, based on SnO2 doped with Sb2O3); and two different electrochemical reactors with and without membrane, EMR and OCR, respectively. All the experiments were under an applied current of 400 mA and at room temperature., The authors want to express their gratitude to the Ministerio de Economía y Competitividad (Spain) and the FEDER funds, which financially support the project RTI2018-101341-B-C21.

[ES] La presente Tesis Doctoral se centra en el estudio del comportamiento electroquímico de nuevos electrodos cerámicos basados en SnO2 dopado con Sb2O3. El estudio está orientado a la posterior aplicación de estos electrodos en procesos electroquímicos de oxidación avanzada. Inicialmente, se consideraron diferentes temperaturas de sinterización (entre 1050°C y 1250°C) y se observó que un aumento en la temperatura de sinterización favorecía la deposición del Sb2O3 en la superficie anódica, disminuyendo así la resistividad del electrodo.
Posteriormente, se estudió el comportamiento electroquímico de estos nuevos electrodos obteniendo el potencial de descarga del oxígeno mediante la técnica de voltametría de barrido lineal. Los resultados obtenidos revelaron que el valor del potencial de descarga del oxígeno disminuye con el aumento de la temperatura de sinterización. Además, estos electrodos presentaron un comportamiento intermedio entre el ánodo de Pt y el ánodo de BDD. Este último electrodo se emplea habitualmente en los procesos electroquímicos de oxidación avanzada debido a su elevada capacidad para generar radicales hidroxilo, los cuales son capaces de oxidar los compuestos orgánicos a dióxido de carbono y agua.
A continuación, se llevaron a cabo ensayos de oxidación electroquímica con estos electrodos cerámicos para seleccionar la temperatura de sinterización. Los resultados mostraron que con el electrodo cerámico sinterizado a 1250°C se alcanza una menor degradación del compuesto orgánico, mientras que los electrodos sinterizados a menores temperaturas presentan un comportamiento similar entre ellos. Por tanto, se seleccionó el electrodo cerámico sinterizado a 1200°C ya que presenta una baja resistividad y un buen comportamiento electroquímico para ser utilizado como ánodo en los procesos electroquímicos de oxidación avanzada.
Seguidamente se analizó la vida útil de estos electrodos cerámicos, y se comprobó que la matriz cerámica incrementa en gran medida la estabilidad a la polarización anódica de los electrodos basados en SnO2.
Posteriormente, se llevaron a cabo procesos de electro-oxidación en modo galvanostático de distintos contaminantes difíciles de eliminar por las técnicas convencionales utilizando como ánodo los nuevos electrodos cerámicos y el electrodo de BDD, para así poder comparar los resultados obtenidos. Se observó que, aunque con los electrodos cerámicos se consigue degradar el 100% de los distintos contaminantes, el electrodo de BDD es el más eficiente ya que genera mayor cantidad de especies oxidantes activas en su superficie. Para un mismo electrodo, se observó que un aumento en la densidad de corriente aplicada mejora la velocidad de degradación y mineralización de cada contaminante, mientras que la eficiencia eléctrica disminuye.
Por otro lado, se estudió el efecto de la presencia de una membrana de intercambio catiónico entre ánodo y cátodo. Los resultados mostraron que el uso de la membrana beneficia la degradación y la mineralización del contaminante, ya que mejora la cinética de reacción anódica y evita la reducción de las especies oxidantes electrogeneradas. A continuación, se analizó la influencia de la concentración del Na2SO4 como electrolito soporte. En este estudio se observó que un aumento en la concentración del Na2SO4 mejora la mineralización del contaminante para el electrodo de BDD y, por el contrario, empeora para el electrodo cerámico. Esto se debe a la capacidad de cada electrodo para oxidar los sulfatos a persulfatos.
Por último, se llevaron a cabo ensayos de ecotoxicidad de las muestras tratadas, y se demostró que, en presencia de membrana, a mayor densidad de corriente y con el electrodo de BDD la toxicidad de la muestra es mayor debido a la mayor presencia en disolución de iones persulfato.
Por tanto, con el electrodo cerámico, además de alcanzar un elevado grado de degradación del contamina, Agradezco al Ministerio de Economía y Competitividad por la financiación recibida mediante los proyectos CTQ2015-65202-C2-1-R y
RTI2018-101341-B-C21, y a la cofinanciación con los fondos FEDER, que han permitido llevar a cabo la investigación en la Universitat
Politècnica de València para la realización de la presente Tesis. También agradecer a Sergio Mestre Beltrán por proporcionarnos los
nuevos electrodos cerámicos en los que se ha basado este trabajo.

[EN]
In recent years, electrodialysis has been often considered as an appropriate method to treat industrial and/or municipal wastewater containing pharmaceutically active compounds. However, the scarcity of information on the ion transport mechanisms through the membranes, especially concerning occurrence of possible sorption phenomena, has limited the process implementation in practice. The present work aims to evaluate, by chronopotentiometry, the transport of sulfamethoxazole (SMX) through a cation- (CEM) and anion-exchange membrane (AEM) using synthetic solutions at different concentrations (0.001-0.1 g/L) and pH conditions (1.6 for CEM and 9 for AEM). The dominant mechanism of mass transfer under overlimiting current conditions at each membrane/solution system was determined. The potential drop profile measured during and after application of current pulses, as well as the transition times obtained from the curves, showed that sorption occurs at/in both membranes, especially for the AEM. Besides, this phenomenon was reversible for the CEM and irreversible for the AEM under the conditions evaluated herein. The chronopotentiograms of the AEM showed that the intense occurrence of water dissociation with the most diluted solution caused chemical equilibrium shifts in the membrane/electrolyte system, leading to formation of neutral SMX species that can impair the electrodialysis performance. The results obtained are useful for optimizing the electrodialytic treatment of SMX-containing solutions as well as of other compounds with similar physicochemical properties., The authors gratefully acknowledge the financial support given by Ministerio de Universidades de Espana (European Union - Next Generation EU) and CNPq (grant numbers 408282/2018-5 and 117290/2021-1). This study was also financed by Grant RTI2018-101341-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe".

[EN] In this work, ecotoxicological bioassays based on Lactuca sativa seeds and bioluminescent bacterium (Vibrio fischeri) have been carried out in order to quantify the toxicity of Norfloxacin (NOR) and sodium sulfate solutions, before and after treating them using electrochemical advanced oxidation. The effect of some process variables (anode material, reactor configuration and applied current) on the toxicity evolution of the treated solution has been studied.

A NOR solution shows an EC50 (5 days) of 336 mg L-1 towards Lactuca sativa. This threshold NOR concentration decreases with sodium sulfate concentration, in solutions that contain simultaneously Norfloxacin and sodium sulfate.

In every case considered in this work, the electrochemical advanced oxidation process increased the toxicity (towards both Lactuca sativa and Vibrio fischeri) of the solution. This toxicity increase is mainly due to the persulfate formation during the electrochemical treatment. From a final solution toxicity point of view, the best results were obtained using a BDD anode in a divided reactor applying the lowest current intensity., The authors are very grateful to the Ministerio de Economia y Competitividad (Projects CTQ2015-65202-C2-1-R and RTI2018-101341-B-C21) for their economic support.

[EN] Norfloxacin is employed as in veterinary and human medicine against gram-positive and gram-negative bacteria. Due to the ineffective treatment at the wastewater treatment plants it becomes an emergent pollutant. Electro-oxidation appears as an alternative to its effective mineralization. This work compares Norfloxacin electro-oxidation on different anodic materials: two ceramic electrodes (both based on SnO2 + Sb2O3 with and without CuO, named as CuO and BCE, respectively) and a boron doped diamond (BDD). First, the anodes were characterized by cyclic voltammetry, revealing that NOR direct oxidation occurred at 1.30 V vs. Ag/AgCl. The higher the scan rate the higher both the current density and the anodic potential of the peak. This behavior was analyzed using the Randles¿Sevcik equation to calculate the Norfloxacin diffusion coefficient in aqueous media, giving a value of D= 7.80¿10-6 cm2 s-1 at 25 °C), which is close to the predicted value obtained using the Wilke-Chang correlation.
The electrolysis experiments showed that both NOR and TOC decay increased with the applied current density, presenting a pseudo-first order kinetic. All the anodes tested achieved more than 90% NOR degradation at each current density. The CuO is not a good alternative to BCE because although it acts as a catalyst during the first use, it is lost from the anode surface in the subsequent uses. According to their oxidizing power, the anodes employed are ordered as follows: BDD>BCE>CuO., The authors want to express their gratitude to the Ministerio de Economia y Competitividad (Spain) and the FEDER funds, which financially support the projects CTQ2015-65202-C2-1-R, CTQ201565202-C2-2-R and RTI2018-101341-B-C21.

[EN] The present manuscript focuses on the study of the electrochemical oxidation of the insecticide Chlorfenvinphos (CVP). The assays were carried out under galvanostatic conditions using boron-doped diamond (BDD) and lowcost tin dioxide doped with antimony (Sb-doped SnO2) as anodes. The influence of the operating variables, such as applied current density, presence or absence of a cation-exchange membrane and concentration of supporting electrolyte, was discussed. The results revealed that the higher applied current density the higher degradation and mineralization of the insecticide for both anodes. The presence of the membrane and the highest concentration of Na2SO4 studied (0.1 M) as a supporting electrolyte benefited the oxidation process of CVP using the BDD electrode, while with the ceramic anode the elimination of CVP was lower under these experimental conditions. Although the BDD electrode showed the best performance, ceramic anodes appear as an interesting alternative as they were able to degrade CVP completely for the highest applied current density values. Toxicity tests revealed that the initial solution of CVP was more toxic than the samples treated with the ceramic electrode, while using the BDD electrode the toxicity of the sample increased., The authors thank the financial support from the Ministerio de Economia y Competitividad (Spain) under the project RTI 2018-101341-B-C21, co-financed with FEDER funds.

[EN] In the present work, microporous ceramics made of antimony-doped tin dioxide produced using a facile synthesis procedure were evaluated during the degradation of norfloxacin in a novel electrofiltration process. The antimony-doped tin dioxide ceramics were used as standalone electrodes accomplishing a dual function: as anodes and microfiltration membranes. The simultaneous generation of hydroxyl radicals and permeation of the electrolyte through the ceramic electrodes favors the effective utilization of their high active area in the degradation of organic compounds. The progress of the electrofiltration process was compared with that of a conventional flow electrolysis reactor using the ceramic electrodes and boron-doped diamond. By changing from a conventional flow reactor to an electrofiltration configuration, the effective utilization of the generated hydroxyl radicals is evidenced by the delayed transition from electrochemical-to mass transfer-controlled degradation rates. Evaluation of intermediate and by-product concentrations confirms the formation of acetate ions as a prior stage in the mineralization pathway using both types of electrodes. After 4 h of electrolysis, norfloxacin degradation rates of 98.3% and mineralization degrees of 82% were attained using the antimony-doped tin dioxide anodes at the highest permeate flow of 60 mL min- 1, approaching the outstanding performance of commercial boron-doped diamond electrodes., Acknowledgements The authors thank the financial support through the project RTI2018-101341-B-C21 funded by MCIN/AEI/10.13039/501100 011033/ (Spain) and by FEDER A way of making Europe.

[EN] The present paper deals with the atenolol (ATL) degradation by advanced anodic oxidation using a boron-doped diamond anode supported on niobium (Nb/BDD). Cyclic voltammetry performed on this electrode revealed that it presents a high quality (diamond-sp3/sp2-carbon ratio), high potential for OER and that ATL can be oxidized directly and/or indirectly by the electrogenerated oxidants, such as hydroxyl radicals, persulfate ions and sulfate radicals. Electrolysis experiments demonstrated that ATL degradation and mineralization follow a mixed (first and zero) order kinetics depending on the applied current density. At high applied current densities, the amount of OH radicals is very high and the overall reaction is limited by the transport of ATL (pseudo first-order kinetics) whereas for low applied current densities, the rate of OH radicals generation at the anode is slower than the rate of arrival of ATL molecules (pseudo-zero order kinetics). Estimated values of kzero and kfirst based on the assumption of pseudo-zero or pseudo-first order kinetics were carried oud as a function of the supporting electrolyte concentration, indicating that both parameters increased with its concentration due the higher production of sulfate reactive species that play an important role in degradation. Finally, MCE increased with the decrease of current density, due to the lower amount of OH present in solution, since this species could be rapidly wasted in parasitic reactions; and the increase of sulfate concentration due to the more efficient production of persulfate., The authors thank the financial support from the Ministerio de Economía y Competitividad (Spain) under projects CTQ2015-65202-C2-1-R and RTI2018-101341-B-C21, co-financed with FEDER funds. The authors thank to FAPERGS, CAPES, FINEP and CNPQ.

[EN] Novel Sb-doped SnO2 ceramic electrodes sintered at different temperatures, are applied to the degradation of Reactive Black 5 in both divided and undivided electrochemical reactors. In the undivided reactor the discoloration of the solution took place via the oxidation of RB5 dye, without the corresponding reduction in the chemical oxygen demand for the ceramic electrodes. However, in the divided one, it was possible to achieve the discoloration of the solution while at the same time decreasing the chemical oxygen demand through the ·OH-mediated oxidation, although the chemical oxygen demand degradation took place at a slower rate., The authors thank the financial support from the Ministerio de Economia y Competitividad (Spain) under projects CTQ2015-65202-C2-1-R and RTI2018-101341-B-C21, co-financed with FEDER funds.

[EN] Electrochemical oxidation of ß-blocker atenolol (ATL, 100 ppm) at different applied current densities (33, 50 and 83 mA·cm-2) using a reactor divided by an ion-exchange membrane and an undivided one was investigated. Two types of anodes were used for this purpose: a boron-doped diamond (BDD) anode and new low-cost ceramic electrodes made of tin dioxide doped with antimony (Sb-doped SnO2). Degradation was assessed using a high performance liquid chromatography, while mineralization by measuring total organic carbon (TOC) dissolved in sample. Except for the lowest current density, ATL was completely degraded for both reactors and electrodes. The highest percentage of TOC eliminated (89%) was obtained at the highest applied current density with the BDD electrode in the divided reactor. The presence of the cation-exchange membrane prevented the reduction of both the electrogenerated oxidizing species and the oxidized organic compounds and enhances the electro-oxidation kinetic reaction.

In order to study the influence of the supporting electrolyte, three different concentrations of sodium sulfate (0.014, 0.05 and 0.1 M) were tested in the undivided reactor with both electrodes. The results showed that an increase in the concentration of the supporting electrolyte improves the mineralization of ATL for the BDD electrode and, on the contrary, worsens for the ceramic electrode. Accelerated service life tests were carried out for the ceramic electrode at 100 mA·cm-2 in 0.5 M H2SO4. Ecotoxicity tests using marine bacteria (Vibrio Fischeri) revealed that no toxic by-products were formed in any case., The authors thank the financial support from the Ministerio de Economia y Competitividad (Spain) under the project RTI2018-101341-B-C21, co-financed with FEDER funds.

[EN] The electrochemical oxidation of the antibiotic Norfloxacin (NOR) in chloride media on different anodic materials was studied at two different electrochemical reactors. The results were compared with those obtained in sulphate media. The anodes under study were a commercial boron-doped diamond (BBD) and two different ceramic electrodes based on tin oxide doped with antimony oxide in the presence (CuO) and absence (BCE) of copper oxide as sintering aid. The reactors employed were a one-compartment reactor (OCR) and a two-compartment one with a membrane separating both electrodes (EMR). The use of the membrane clearly enhanced both NOR degradation and TOC mineralization for all the anodic materials studied since some parallel reactions were avoided. Additionally, two different pathways for NOR oxidation were observed as a function of the reactor employed. The EMR also favoured the ionic by-products generation and the electrolyte dechlorination. NO3¿ increased with the oxidation power of the anode employed and it was also enhanced by the EMR use. Chloride media favours ceramic electrodes performance independently of the reactor employed as they did not generate an excess of oxidants as BDD did. The BCE electrode is an interesting alternative to BDD since although its oxidative power was lower, it presented similar current efficiency with lower energy consumption., The authors want to express their gratitude to the Ministerio de Economia y Competitividad (Spain) and the FEDER funds, which financially support the project RTI2018-101341-B-C21.

[EN] As part of the Brazilian Popular Pharmacy Program, the beta-blocker Atenolol (ATN) is widely used, and its presence in the environmental ecosystems is a reality. Aiming the ATN removal, the use of an electrochemical membrane reactor was evaluated and compared to a membraneless one. The results show that the generation of SO4 center dot- in the membrane reactor occurs by the reaction of HSO4-/H2SO4 scavenging HO center dot-, whereas, in the membraneless reactor, the SO4 center dot- generation occurs mainly by the direct oxidation mechanism. Operating both reactors in the same hydrodynamic conditions, it was found that the concentrations of SO4 center dot- and S(2)O8(2)(-) are higher in the membrane reactor, leading to a greater concentration of these species being transported to the bulk solution, changing the kinetics, and presenting better results in electrochemical combustion (phi), mineralization current efficiency (MCE) and specific energy consumption (Es). Since the mass transport limitations were overcome in membrane reactor, the processes may find their good applications in water and wastewater treatment., The authors are grateful to the Brazilian funding agencies (FAPERGS, CAPES, CNPq and FINEP), to the Programa Iberoamericano de Ciencia y Tecnologia para el Desarollo (CYTED), and to the Ministerio de Ciencia, Innovacion y Universidades (Spain) under the project RTI2018-101341-B-C21, co-financed with FEDER funds