Articles publicats en revistes (Ciència dels Materials i Química Física)

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Superhydrophobic $\mathrm{FeNi_{3}/Al_{2}O_{3}}$multifunctional hybrid Janus particles for the catalytic degradation of azo dye, oil/water separation and microplastics removal
(Elsevier, 2024-10-14) Rius Ayra, Oriol; Llorca i Isern, Núria
Emerging pollutants are causing global health and environmental challenges, necessitating the advancement of methodologies for their efficient removal. In this study, we present the efficacy of superhydrophobic $\mathrm{FeNi_{3}/Al_{2}O_{3}}$ Janus particles in the removal of oils and microplastics from water, combined with the degradation of azo dyes, leveraging their surface properties. Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDS) revealed the morphology and elemental composition of these particles, which were further complemented by X-ray diffraction (XRD) for phase identification. After surface functionalization of the $\mathrm{FeNi_{3}/Al_{2}O_{3}}$ Janus particles with lauric acid, they exhibited superhydrophobicity (152 ± 1°) and superoleophilicity (0°). High-resolution X-ray photoelectron spectroscopy (HR-XPS) showed that the alumina face was modified with lauric acid, while the intermetallic $\mathrm{FeNi_{3}}$. Significantly, the alumina face demonstrated 99 % efficiency in separating oils and microplastics, while the $\mathrm{FeNi_{3}}$ face facilitated the complete degradation (100 %) of methyl red within three minutes, as shown by ultraviolet-visible spectrophotometry. These results highlight the multifunctional properties of superhydrophobic $\mathrm{FeNi_{3}/Al_{2}O_{3}}$ Janus particles in removing and degrading various pollutants.
Chemical bonding and electronic properties along Group 13 metal oxides
(Springer Verlag, 2024-05-07) Kapse, Samadhan; Voccia, Maria; Viñes Solana, Francesc; Illas i Riera, Francesc
The present work provides a systematic theoretical analysis of the nature of the chemical bond in Al 2 O 3, Ga 2 O 3 ,and In2O3 group 13 cubic crystal structure metal oxides. The influence of the functional in the resulting band gap is assessed. The topological analysis of the electron density provides unambiguous information about the degree of ionicity along the group which is linearly correlated with the band gap values and with the cost of forming a single oxygen vacancy. Overall, this study offers a comprehensive insight into the electronic structure of metal oxides and their interrelations. This will help researchers to harness information effectively, boosting the development of novel metal oxide catalysts or innovative methodologies for their preparation.
Chemical Procedures for Paint Removal in Used Thermoplastics for Revalorization as a Raw Material in the Automotive Industry
(Wiley Hindawi Publishing, 2025-03-30) Zambrano Membrives, Carla; Tamarit, Pablo; Fernández Renna, Ana Inés; Barreneche, Camila
The recycling of thermoplastic polymers from end-of-life vehicles is crucial to achieve a circular economy within the sector and prevent the accumulation of plastic waste by reusing it. However, several challenges in these processes present difficulties, making it challenging or impossible to recycle these materials for the same applications, impeding the closure of the life cycle and valorization of waste. The primary problem faced by plastic converters is the presence of superficial paint. In this study, we evaluate the implementation of chemical methods with varying conditions to remove paint from used bumpers thermoformed with polypropylene, with the aim of valorizing the plastic waste from these bumpers. We examine the various process variables, such as reagent concentration, temperature, time, and pH. Additionally, we analyze procedures to quantify the paint content in the different recycled samples and use this as a tool to compare the effectiveness of different paint removal processes.
Surface modification of hierarchical hydroxyapatite fabricated via hydrothermal method
(Elsevier B.V., 2024-06-01) Mohandes, Fatemeh; Gómez, Elvira; Serrà i Ramos, Albert
Surface modification, encompassing both chemical and physical features, plays a crucial role in fulfilling the requirements of biomaterial applications and also improves their performance. Due to that, this study focuses on the optimization of morphology and functionalization of hydroxyapatite (HAP). For this purpose, hydrothermal growth of HAP on (fluorine tin oxide) FTO is carried out in the presence of calcium and phosphate precursors with Ca/P molar ratio of 1.67:1 in the solution. Trisodium nitrilotriacetic acid (NTA) is used as a chelating additive for the first time during hydrothermal process at temperature between 120 and 180 °C for 16–24 h. Further studies on the effect of NTA concentration on HAP formation indicate that hierarchical structures are formed in the presence of NTA with NTA/Ca molar ratio of 1:1 at temperature between 150 and 180 °C for 24 h, improving crystallinity as temperature increasing. To facilitate the functionalization of HAP, the layer deposited at 180 °C with NTA/Ca molar ratio of 1:1 is peeled using two different reagents, Fluoromount™ and polyvinyl alcohol (PVA). The HAP peeled with PVA shows no relevant morphological changes in SEM images, indicating a successful peeling process using PVA. After that, the HAP powders are functionalized with alendronate (AL) molecules and studied using ATR-FTIR, XPS and BET techniques. Chemical shift of PO43− vibrations and appearance of the new peaks assigned to the –NH2 group demonstrate successful AL-functionalization. The AL-HAP hierarchical structures fabricated with the aid of NTA can be introduced as multifunctional biomaterials for future bio-applications.
Nonorthogonal Configuration Interaction for Singlet Fission:Beyond the Dimer
(American Chemical Society, 2025-02-17) Sousa Romero, Carmen; López, Xavier; Dong, Xing; Broer, Ria; Straatsma, T. P.; de Graaf, Coen
Non-orthogonal configuration interaction with fragment calculations are presented for a number of compounds that show singlet fission properties: (i) four perylene-diimide derivatives, (ii) crystalline pentacene and its (B,N)-substituted variant, and (iii) a regular and a distorted stack of three indolonaphthyridine molecules. The electronic couplings between the singlet excitonic states (S1) and the singlet-coupled double triplet (T1T1), the so-called singlet fission coupling, were computed from ensembles with two and three molecules, and except for some small deviations when charge transfer states were included, results are virtually the same. Ensembles of three molecules were used to study the mechanisms of triplet separation, double triplet diffusion, and singlet and triplet exciton diffusion. The calculations show that apart from the standard mechanism for the generation of two uncoupled triplet states (S1 → T1T1 → T1...T1), there are two other possible pathways: the direct generation from the singlet excitonic state (S1 → T1...T1) and the process in which the excitonic state evolves in a superposition of T1T1 and T1...T1 states. The electronic coupling for triplet diffusion is in general much smaller than for singlet diffusion.
MXenes Surface Termination under Photoexcitation: Insights from Excited-State Pourbaix Diagrams
(American Chemical Society, 2026-03-10) Ontiveros Cruz, Diego; Viñes Solana, Francesc; Sousa Romero, Carmen
MXenes have emerged as promising materials for photocatalytic hydrogen production, yet their performance is critically dependent on the specific nature of their surface terminations. While Pourbaix diagrams are routinely used to map surface stability under a certain pH and applied external potential (U), they traditionally neglect the influence of photoexcitation on thermodynamic preference. Here, we construct the singlet (S0) ground state and the lowest triplet (T1) excited state Pourbaix diagrams for Sc2C, Y2C, and Zr2C MXenes, which have previously shown promising photoactive properties, to assess how photo- excitation alters surface stability. Our results show that constant photoexcitation can significantly reshape the Pourbaix diagrams, altering the thermodynamically preferred surface terminations and thereby influencing photocatalytic behavior. Across all studied systems, terminations associated with aqueous acidic etching environments (−F,−O,−OH,−H) dominate the stability regions. For Zr2C, this is advantageous since−O termination is both the most stable and photoactive configuration. In contrast, for Sc2C and Y2C, the potentially more active halide and chalcogen terminations are overshadowed by aqueous- and HF-derived groups, suggesting that alternative synthesis routes will be required to stabilize the most photocatalytically favorable terminations.
Selective Hydrodemethylation of Methylalkylbenzenes on Potassium Hydride
(Wiley-VCH, 2025-12-24) Tian, Puyang; Figueras Valls, Marc; Chang, Fei; Viñes Solana, Francesc; Illas i Riera, Francesc; Fedorov, Alexey
Dealkylation and hydrodealkylation of alkylaromatics are key processes in the petrochemical industry. The typical susceptibility of alkyl groups to removal via both dealkylation and hydrodealkylation reactions in aromatic compounds follows the order CH3 < 1° < 2° < 3°, with methyl and tertiary alkyl groups having the slowest and fastest reaction rates, respectively. Here, we report the selective catalytic hydrodealkylation of methylalkylbenzenes using carbon-supported potassium hydride (KH/C) under a H2 atmosphere, which exhibits an opposite reactivity pattern compared with that described above. This trend is observed across various methylalkylbenzenes and also aligns with the higher reactivity of toluene compared to other monoalkylbenzenes. Density functional theory calculations on ortho-ethyltoluene as a model substrate rationalize the experimental results by indicating a lower rate-limiting energy barrier for the direct removal of the methyl group as methane relative to the removal of the ethyl group as ethane on the (001) facet of KH. Our study reveals that the potassium hydride surface exhibits a distinct hydrodealkylation mechanism, characterized by selectivity for hydrodemethylation, which contrasts with that of zeolites, Mo- or Pt-based hydrodealkylation catalysts, and homogeneous free-radical pathways.
Boosting Drug Discovery: Expanding the Applicability of Fragment Dissolved Molecular Dynamics to Accelerate Binding Mode Elucidation
(American Chemical Society, 2025-11-24) Peralta Moreno, María Nuria; Granadino-Roldán, José Manuel; Santos Tomas, M.; Rubio Martínez, Jaime
The use of small organic molecules has become one of the most popular strategies in computer-aided drug design (CADD) to facilitate the identification of potential drug-like compounds in the early stages of drug development. In this scenario, novel computational approaches such as the use of thefragment dissolved molecular dynamics (fdMD) methodology emerged as a new framework for the modeling of ligand−receptor interactions. Consisting of molecular dynamics (MD) simulations of the target protein solvated with multiple copies of the same fragment, the original approach is able to identify the most favorable binding site for the system studied in a reasonable simulation time scale (0.2−1 μs). In the present work, we have introduced the use of Gaussian accelerated molecular dynamics (GaMD) to facilitate system exploration, accelerate binding site identification and additionally enhance binding mode elucidation. For this purpose, up to 12 different systems with crystallographic information available have been employed for validation.
THz-based monitoring of the deformation of the inner woven structure of glass fiber reinforcedpolymers
(Institute of Electrical and Electronics Engineers (IEEE), 2023-05-11) Pomarède, Pascal; Calvo de la Rosa, Jaume; Antonik, Piotr; Meraghni, Fodil; Citrin, David S.; Rontani, Damien; Locquet, Alexandre
This work exploits terahertz (THz) imaging in the real-space and the spatial-frequency domain to determine nondestructively the evolution of the main characteristics of a woven glass-fiber reinforced polymer laminate in three-dimensions in situ during a tensile test. These characteristics include tow orientation and the weave period. The surface and the inner plies can be investigated with the proposed method. The results show how the tows tend to realign with the load direction. In addition, we detect a decrease in the weave period, manifesting a distortion of the surface and inner layers as the stress is increased. Contrary to conventional optical inspection, THz inspection can provide quantitative measurements in all material layers and not only on the surface. This technique could be helpful to monitor distortion and damage due to mechanical stress or defects incorporated during the manufacturing process and to validate parameters and results of draping process modeling, especially for the inner plies.
Terahertz permittivity of pressed ZnO and CuO powder in polyethylene pellets: Effect of porosity
(Institute of Electrical and Electronics Engineers (IEEE), 2021-03-05) Calvo de la Rosa, Jaume; Locquet, Alexandre; Bouscaud, Denis; Berveiller, Sophie; Citrin, David S.
Terahertz (THz) spectroscopy is used to measure permittivity (100 GHz-2.5 THz) of ZnO and CuO powders with low fill factor pressed into pellets in a polyethylene binder. We show that porosity (air) of such pressed pellets has a large effect on effective pellet permittivity (~10 %) and on the extracted permittivity of the oxide constituent (~150 %). We explore a two-step analysis based on sequential application of different effective medium models (EMMs), first to account for the air, and subsequently to extract the oxide's dielectric properties. We show that the combination of Vegard's law and the Maxwell-Garnett model is the best combination to account, respectively, for the air and the oxide powders. In this regard, the capacity that this approach has to adapt to each phase's physical characteristics by using multiple EMMs is an advantage. The resulting oxide permittivities are significantly larger than previously reported for such pellets as a consequence of the porosity. We find for the real relative permittivities of CuO and ZnO ~12.1 and ~8.9, respectively, in the THz range.
Synergistic photothermal/photocatalytic activation of peroxymonosulfate using $SrFe_{12}O_{19}$@Ni-P core@shell microparticles for energy efficient water remediation
(Elsevier B.V., 2026-02-04) Bautista, Queralt; Rigual Miret, Jordi; Lloreda Rodes, Judit; Fons, Arnau; Nogués, Josep; Gómez, Elvira; Sepúlveda, Borja; Serrà i Ramos, Albert
The urgent need for more efficient water remediation systems requires the development of new low cost and low energy strategies to remove persistent organic pollutants. This work investigates the activation of peroxymonosulfate (PMS) using Ni-P-coated SrFe12O19 (SFO@Ni-P) microparticles under thermal, photothermal and photocatalytic conditions by either conventional heating or near-infrared (NIR; 915 nm) or blue (450 nm) light activation. The synergistic photothermal/photocatalytic activation using blue light (i.e., above the SFO bandgap) outperformed conventional thermal treatments or photothermal NIR activation, enhancing the PMS decomposition at moderate temperatures. The outstanding performance of SFO@Ni-P was due the combination of Ni2+/Ni3+ redox cycling and the highly damped plasmonic behavior or the Ni-P shell, and the photothermal/photocatalytic activation offered by the semiconducting SFO core, leading to >99.9% degradation and 99.9–100.0% mineralization of tetracycline after 90 min under blue-light (combined photothermal/photocatalytic) activation. Moreover, the dual photothermal/photocatalytic effects under blue light enabled up to 87.4% mineralization of a 120 ppm multi-pollutant mixture in 90 min, with markedly lower electrical energy per order (EE/O) (≈4-fold) than conventional thermal activation. The catalysts maintained high activity over multiple cycles with negligible metal leaching. Remarkably, under sunlight the catalyst achieved nearly complete multi-pollutant mineralization (≈99%) within 40 min without external electrical input for heating/irradiation (excluding ancillary power). Importantly, seed germination/root elongation assays confirmed strong detoxification of the treated effluents (GI > 80%). These findings highlight the potential of SFO@Ni-P microparticles for efficient, reusable, and low-energy advanced oxidation processes, and solar-compatible wastewater treatment applications.
Colloidal Cards: Effects of Game-Based Learning on Student’s Achievements in Colloidal Science
(Division of Chemical Education of the American Chemical Society., 2024-11-11) Gómez, Elvira; Sousa Romero, Carmen; Serrà i Ramos, Albert
Educational games garnered significant attention as effective learning tools, blending proven efficiency in improving learning outcomes with engaging and appealing environments that foster peer collaboration. Despite the central role of colloids in chemical applications, colloidal chemistry is often addressed superficially or qualitatively in many university settings, frequently relegated to noncompulsory subjects. Yet, the profound industrial and technological applications of colloidal chemistry, spanning fields like food, biomedicine, and paints, make it one of the most socially and economically impactful branches of chemistry globally. Hence, there is a pressing need to create effective tools that facilitate the teaching of colloidal systems, aiding in the comprehensive understanding of their characteristics and properties. This paper introduces a novel educational game named “Colloidal Cards” designed as an auxiliary tool for teaching and learning colloidal systems. The game aims to achieve three primary objectives: (i) facilitate the identification of everyday and industrial colloidal systems; (ii) impart knowledge on the key physicochemical properties of colloidal systems; and (iii) enhance comprehension of the stability of colloidal systems and the mechanisms to destabilize them.
Biocompatible 3D printed yttria-stabilized zirconia parts using direct ink writing
(SAGE Publications, 2024) Buj Corral, Irene; Sanz Fraile, Héctor; Tejo-Otero, Aitor; Vidal, Daniel; Padilla Sanchez, Jose Antonio; Xuriguera Martín, María Elena; Otero Diaz, Jorge
Metals such as titanium or Cr-Co alloys have been the most widely used materials in biomedical applications that requirehigh mechanical properties, like implants. However, these materials present the disadvantage of releasing ion metals intothe body. As an alternative, prostheses made of ceramic materials have been developed, as they produce less debris andhave better durability. The aim of the present work is to test the biocompatibility of 3D-printed yttria-stabilized zirconiaparts by culturing human bone-marrow-derived mesenchymal stem cells. Two different scaffols were 3D printed having aliner infill pattern, with 80 % and 95 % infill rate respectively. Results on surface roughness and biocompatibility testsconfirmed that 3 mol % yttria-stabilized zirconia is a highly promising material as it presented high biocompatibility. In adition,similar results were obtained with or without the use of a type I collagen coating., which suggest that coating couldbe avoided when on zirconia substraes.
Nitrogen embedding enhances stability and activity of single-atom motifs of MXenes under anodic polarization
(Springer Nature, 2025-10-31) Meng, Ling; Razzaq, Samad; Singh, Diwakar; Viñes Solana, Francesc; Illas i Riera, Francesc; Exner, Kai S.
MXenes undergo water-mediated surface reconstruction under anodic polarization and spontaneously form single-atom centers, reminiscent of single-atom catalysts (SAC), which exhibit great potential for the oxygen evolution reaction (OER). Yet, the as-formed SAC-type MXene motifs still suffer from the conventional activity-stability trade-off under OER conditions. Here, we propose a nitrogen embedding strategy to modulate the local coordination environment of the single-atom centers, thereby enhancing both their stability under anodic polarization and OER activity. Based on density functional theory calculations, we systematically evaluate 53 N-doped SAC-type MXene motifs, covering M2X1O, M3X2O, and M4X3O MXenes, using a three-step screening approach, which identifies promising candidates that (i) allow nitrogen doping under anodic polarization, (ii) are thermodynamically stable under OER conditions, and (iii) exhibit high OER activity. We demonstrate that N-doped Ta2C1O and Ta2N1O SAC-like MXenes break the traditional activity-stability trade-off in OER and provide theoretical guidance for designing efficient and durable SAC-like MXene electrocatalysts.
Peroxymonosulfate activation on the S-scheme heterojunction Bi4O5I2/TiO2 photoanode of a photocatalytic fuel cell for degradation of tetracyclines with green power generation.
(Chinese Academy of Sciences, 2025-10-10) Wu, Huizhong; Liang, Ruiheng; Chen, Yujie; Zhang, Xiuwu; Liu, Jingyang; Xia, Zehua; Sirés Sadornil, Ignacio; Zhou, Minghua
Photocatalytic fuel cells (PFC) are green devices for simultaneous contaminant degradation and power generation. However, their performance is still limited due to the inefficient light capture and poor charge transfer at photoanodes. Here, a PFC has been successfully developed using a Bi4O5I2/TiO2 nanotube arrays (NTAs) S-scheme heterojunction as the photoanode, incorporating peroxymonosulfate (PMS) as synergistic precursor of reactive oxygen species (ROS). A 17-fold increase in rate constant for the degradation of tetracycline (TC) and 6.6-fold increase in maximum power generation was attained in comparison with the TiO2/light PFC system. A systematic analysis elucidating PMS-mediated regulation of ROS generation and electron transfer was performed. The photocatalytic mechanism, dominated by non-radical 1O2 and photogenerated holes (h+), led to a maximum photocurrent density (0.091 mA cm−2) and output power (0.99 mW cm−2). The current work demonstrates the great robustness of heterojunction-based PFC as new self-powered water decontamination systems.
Unlocking the predictive power of quantum-inspired representations for intermolecular properties in machine learning
(Royal Society of Chemistry (RSC), 2024-01-17) Santiago, Raul; Vela Llausí, Sergi; Deumal i Solé, Mercè; Ribas Ariño, Jordi
The quest for accurate and efficient Machine Learning (ML) models to predict complex molecular properties has driven the development of new quantum-inspired representations (QIR). This study introduces MODA (Molecular Orbital Decomposition and Aggregation), a novel QIR-class descriptor with enhanced predictive capabilities. By incorporating wave-function information, MODA is able to capture electronic structure intricacies, providing deeper chemical insight and improving performance in unsupervised and supervised learning tasks. Specially designed to be separable, the multi-moiety regularization technique unlocks the predictive power of MODA for both intra- and intermolecular properties, making it the first QIR-class descriptor capable of such distinction. We demonstrate that MODA shows the best performance for intermolecular magnetic exchange coupling (JAB) predictions among the descriptors tested herein. By offering a versatile solution to address both intra- and intermolecular properties, MODA showcases the potential of quantum-inspired descriptors to improve the predictive capabilities of ML- based methods in computational chemistry and materials discovery.
X-ray diffraction pattern analysis of CrFeCoNi high-entropy alloy deposited via cold spray
(International Centre for Diffraction Data, 2025-12) Silvello, A. (Alessio); Cabrera, José María; García Cano, Irene; Aguilar, Claudio
CrFeCoNi high-entropy alloy (HEA) powder with an equimolar composition was produced via gas atomization and applied as a coating using the cold-spray technique. X-ray diffraction patterns were analyzed to characterize the microstructure of the raw HEA powder and cold-sprayed coatings using Rietveld refinement methods. The HEA powders exhibited a single-phase face-centered cubic crystal structure with a lattice parameter of 0.357349(1) nm, a low microstrain of 4.3(0.17) × 10−4, and a crystallite size of 225(8) nm, attributed to the rapid cooling during atomization. In contrast, the cold-sprayed coatings exhibited broadened diffraction peaks, with a reduced crystallite size of 67.9(1.2) nm and an increased microstrain of 2.2(0.23) × 10−3, showing crystallite size refinement and an increase in the density of crystalline defects due to severe plastic deformation during deposition. Additional microstructural analysis revealed texture in the {200} plane and intrinsic stacking fault probabilities increasing to 4.4(0.21) × 10−3. These findings highlight microstructural changes produced by the cold-spray process. This study provides valuable insights into optimizing cold-spray parameters and tailoring HEA properties for industrial applications.
Efficiency of Orthodontic Adhesives: Influence of Saliva and Shear Direction - in vitro study
(MDPI, 2026-02-11) Ignatova, Tatiana; Xuriguera Martín, María Elena; d'Oliveira, Nuno Gustavo; Sánchez Molins, Meritxell
This in vitro study evaluated the shear bond strength (SBS) and adhesive remnant index (ARI) of orthodontic molar tubes bonded using conventional, hydrophilic, and self-etch adhesives under dry and saliva-contaminated conditions, while also assessing the impact of shear force direction. Extracted molars were bonded with Transbond XT™ (T), Transbond MIP™ (M), or Scotchbond Universal™ (S) under dry or saliva-contaminated conditions. Debonding was performed at 90° or 45°, introducing a clinically relevant but underexplored variable in orthodontic bond-strength testing. ARI scores were assessed via stereomicroscopy and visual inspection. Statistical tests (Kruskal–Wallis and Mann–Whitney) showed no significant SBS differences among adhesives under identical conditions (p > 0.05). However, all adhesives exhibited significantly reduced SBS under saliva contamination (p < 0.001; T: 5.4 vs. 4.1 MPa; M: 5.7 vs. 3.6 MPa; S: 5.5 vs. 4.5 MPa). In dry conditions, SBS was significantly higher with 45° debonding (p < 0.05). Under contamination, SBS varied by ARI score (p = 0.05), with ARI 0 specimens showing higher SBS than ARI 3. These findings confirm that moisture reduces bond strength across adhesive types, while 45° force application enhances SBS under dry conditions. ARI score variability under contamination may reflect complex failure modes.
Machine Learning Potential Analysis of Structural Transition in Cu and Ag Nanoparticles: From Icosahedral to Face-Centered Cubic
(American Chemical Society, 2025-09-09) Yang, Yongpeng; Han, Jingli; Viñes Solana, Francesc; Illas i Riera, Francesc
A highly accurate high-dimensional neural network potential (HDNNP), trained using more than 180,000 DFT-calculated structures, is used to investigate the structure or realistic Cu−Ag bimetallic particles, as this is the dominant species during the CO2 reduction process. The structural transition of Cu and Ag nanoparticles of increasing size, ranging from hundreds of atoms to tens of thousands of atoms, has been studied. Global optimization shows that all Cu and Ag nanoparticles containing 100 to 1000 atoms have an icosahedral core. Upon increasing the number of atoms to 6000 and 10,000 for Cu and Ag, respectively, the nanoparticles’ structural transitions from icosahedral to truncated-octahedral. For even larger nanoparticles, the (100)/(111) surface ratio in truncated-octahedral structures increases, which finally leads to a transformation into the cuboctahedral shape as observed in experiments.
Assessing the HClO/Fe^2+Fenton-like reaction for the degradation of metronidazole in a flow cell equipped with a Ti-Ru-Ir oxides anode
(Elsevier, 2026-02-09) Rodríguez, Juan F.; Cornejo, Oscar M.; Sirés Sadornil, Ignacio; Nava, José L.
This work examines the electrochemical mineralization of metronidazole (MTZ) via the photoelectro-Fenton-like (PEF-like) process in a flow plant utilizing a filter-press electrolyzer with a Ti|Ti-Ru-Ir-oxides anode. The process uses the chloride ions contained in a dilute solution to form HClO through direct anodic oxidation on the Ti|Ti-Ru-Ir-oxides anode. Then, HClO reacts with ferrous ion (Fe2+) to yield ferryl-oxo species (FeIVO2+) and hydroxyl radicals (•OH), which are responsible for the mineralization of MTZ to CO2. The influence of the current density (j), as well as the initial Cl-, Fe2+, and MTZ concentrations was systematically examined to determine the best experimental conditions for MTZ degradation. A comparison of electro-oxidation aided with active chlorine (EO-HClO), electro-Fenton-like (EF-like), and PEF-like processes for the elimination of MTZ indicates the superiority of the latter one. The use of scavengers indicates that FeIVO2+ is the main oxidant (58 %), with minor contributions from •OH (13 %) and other routes, such as electro-oxidation and chlorination. Optimum PEF-like conditions for the complete degradation of 20 mg L-1 MTZ involved the use of 0.4 mM Fe2+ in a 35 mM NaCl+ 50 mM Na2SO4 electrolyte, at j = 16 mA cm-2 and u = 10 cm s-1, with an electrolytic energy consumption of 0.9 kWh (g TOC)-1. Up to 78 % of mineralization was attained, where the residual dissolved organic matter mainly consisted of oxalic acid and N-derivatives.

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