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

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The recent development of innovative photoelectro-Fenton processes for the effective and cost-effective remediation of organic pollutants in waters
(Elsevier Ltd., 2024-10-08) Brillas, Enric; Peralta-Hernández, Juan Manuel
Wastewaters with toxic and recalcitrant organic contaminants are poorly remediated in conventional wastewater treatment plants. So, powerful processes need to be developed to destroy such organic pollutants to preserve the quality of the aquatic environment. This critical and comprehensive review presents the recent innovative development of photoelectro-Fenton (PEF) covering the period 2019–September 2024. This emerging photo-assisted Fenton-based electrochemical advanced oxidation process (EAOP) is an efficient and cost-effective treatment for water remediation. It possesses a great oxidation power because the in-situ generated hydroxyl radical as oxidant is combined with the photolysis of the organic by-products under UV or sunlight irradiation. The review is initiated by a brief description of the characteristics of the PEF process to stand out in the role of generated oxidizing agents. Further, the homogeneous PEF. PEF-like, solar PEF (SPEF), and SPEF-like processes with iron catalysts are discussed, taking examples of their application to the removal and mineralization of solutions of industrial chemicals, herbicides, dyes, pharmaceuticals, and direct real wastewaters. Novel heterogeneous PEF treatments of such pollutants with solid iron catalysts or functionalized cathodes are analyzed. Finally, novel hybrid processes including PEF/photocatalysis and PEF/photoelectrocatalysis, followed by novel and potent sequential processes like electrocoagulation-PEF and persulfate-PEF, are discussed. Throughout the manuscript, special attention was made to the total operating cost of PEF, which is more expensive than conventional electro-Fenton due to the high electric cost of the UV lamp, pointing to consider the much more cost-effective SPEF as a preferable alternative in practice.
Eliminació d'antibiòtics de matrius aquoses sintètiques i reals mitjançant processos d'oxidació avançada basats en peroximonosulfat. Una revisió dels desenvolupaments recents
(Elsevier Ltd., 2024-01-12) Brillas, Enric; Peralta-Hernández, J.M.
The widespread use of antibiotics for the treatment of bacteriological diseases causes their accumulation at low concentrations in natural waters. This gives health risks to animals and humans since it can increase the damage of the beneficial bacteria, the control of infectious diseases, and the resistance to bacterial infection. Potent oxidation methods are required to remove these pollutants from water because of their inefficient abatement in municipal wastewater treatment plants. Over the last three years in the period 2021–September 2023, powerful peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) have been developed to guaranty the effective removal of antibiotics in synthetic and real waters and wastewater. This review presents a comprehensive analysis of the different procedures proposed to activate PMS-producing strong oxidizing agents like sulfate radical (SO4•−), hydroxyl radical (•OH, radical superoxide ion (O2•−), and non-radical singlet oxygen (1O2) at different proportions depending on the experimental conditions. Iron, non-iron transition metals, biochar, and carbonaceous materials catalytic, UVC, photocatalytic, thermal, electrochemical, and other processes for PMS activation are summarized. The fundamentals and characteristics of these procedures are detailed remarking on their oxidation power to remove antibiotics, the influence of operating variables, the production and detection of radical and non-radical oxidizing agents, the effect of added inorganic anions, natural organic matter, and aqueous matrix, and the identification of by-products formed. Finally, the theoretical and experimental analysis of the change of solution toxicity during the PMS-based AOPs are described.
Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) Studies of Porphyrin Adsorption on Graphene: Insights on the Effect of Substituents and Central Metal on Adsorption Energies
(Wiley, 2024-12-05) Gara, Rayene; Morales García, Ángel; Arfaoui, Youssef; Illas i Riera, Francesc
Combining metalloporphyrins (MPr) and graphene constitutes key composites in the development of photovoltaic devices. Here, we focus on the analysis of the properties of metalloporphyrins/graphene systems by means of the density functional theory (DFT) and its time-dependent (TDDFT) version, focusing on the ground and singlet excited states. Our benchmark analysis concludes that ωB97XD density functional combined with 6-31G(d)/Def2-TZVP basis set is a better-suited method for simulating accurate MPr adsorption on graphene. It is shown that a reduced atomic model where the external organic shell of the structure is removed provides the same resulting optoelectronic properties of the original model, constituting an important speed-up of the calculations when studying porphyrins-derived molecules. We observe that ZnPr provides the highest light harvesting efficiency (LHE) value. In addition, we find out that the adsorption energy increases monotonically with the size of the graphene flake and the highest stability involves the use of graphene comprising above 500 atoms. Besides, CdPr and HgPr keep their properties as photosensitizers when they are bonded to graphene and show promising values in terms of LHE emerging as suitable solar energy harvesters.
Redesigning electrochemical-based Fenton processes: An updated review exploring advances and innovative strategies using phenol degradation as key performance indicator
(Elsevier B.V., 2024-09-01) Brillas, Enric; Garcia Segura, Sergio
The removal of toxic and persistent organic pollutants is one of the major engineering challenges for water treatment. Development of Fenton-based advanced oxidation processes (AOPs) has shown promising results over water remediation control. The present critical review presents a benchmark framework of understanding on the recent advances of such Fenton-based AOPs based on the abatement of phenol as model pollutant, considering articles published in the period 2019–2023. Fundamentals, the effect of operating variables over the degradation and mineralization of phenol waters, and the role of in situ generated oxidizing agents are summarized and analyzed for understanding the competitiveness and niche application of processes such as homogeneous and heterogeneous Fenton, homogeneous photo-Fenton, hybrid heterogeneous photocatalysis/photo-Fenton, homogeneous and heterogeneous electro-Fenton, and photoelectro-Fenton. Especial emphasis is made on strategies designed to overcome the narrow pH limitation to 3.0 of Fenton reaction. A comparative cost analysis of the above homogeneous processes revealed that homogeneous electro-Fenton was the most viable and cost-effective process. The present review shows that phenol can be used as reference to assess the notable impact of recent advances of Fenton-based AOPs.
Design of donor–acceptor type benzotrithiophene-based covalent organic frameworks for visible-light-driven overall water splitting
(Elsevier Ltd., 2025-12-23) Wang, Chao; Ontiveros Cruz, Diego; Sousa Romero, Carmen
Benefitting from the abundant accessible catalytic sites and well-defined porous architectures enhancing mass transport, two-dimensional (2D) covalent organic frameworks (COFs) are emerging as promising photocatalysts for overall water splitting (OWS). However, the performance of many known COFs for this application remains unsatisfactory, primarily due to stringent requirements for precise band alignment, the limitation posed by overpotentials in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and mutual interference between the two half-reactions. Herein, we propose eight donor–acceptor (D–A) type 2D benzotrithiophene-based COFs (BTT-COFs), constructed from experimentally feasible building blocks via Schiffbase condensation reaction. By incorporating D–A pairs into the frameworks, these BTT-COFs exhibit enhanced intermolecular charge transfer characteristics as anticipated, thereby promoting efficient carrier separation during OWS. Concurrently, the D–A combinations enable precise modulation of the electronic structure, affording band gaps ranging from 2.35 to 2.89 eV with band-edge arrangements appropriately aligned for photocatalytic OWS under neutral conditions (pH = 7). Among them, the BTT-COF1 (incorporating benzotrithiophene and 1,3,5-triaminobenzene), BTT-COF2 (featuring benzotrithiophene and 2,4,6-triamino-1,3-diazine), and BTT-COF3 (consisting of benzotrithiophene and 2,4,6-triamino-1,3,5-triazine) are found to be capable of spontaneously driving OWS under their intrinsic photoinduced bias potentials. The remaining BTTCOFs require external bias to facilitate the reaction. Crucially, the theoretical solar-to-hydrogen (STH) conversion efficiencies of these materials range from 1.8 % to 10.0 %, highlighting their potential as efficient photocatalysts for OWS.
First principles modeling of composites involving TiO2 clusters supported on M2C MXenes
(Royal Society of Chemistry, 2024-12-01) Keyhanian, Masoomeh; García-Romeral, Néstor; Morales García, Ángel; Viñes Solana, Francesc; Illas i Riera, Francesc
First-principles calculations based on density functional theory are performed to investigate the formation of titania/MXene composites taking (TiO2)5/M2C (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W) as cases of study. The present systematic analysis confirms a favorable, high exothermic interaction, which promotes important structural reconstructions of the (TiO2)5 cluster along with charge transfer from the MXene to titania. MXenes composed of d3 transition metals promote the strongest interaction, deformation energy, and charge transfer, followed by d4 and d5 M2C MXenes. We provide evidence that the formation of these (TiO2)5/M2C composites is governed by charge transfer, leading to scaling relationships. By using the electronegativity of the metal composing MXene and the MXene d-band center, we also establish linear correlations that can be used to predict the interaction strength of (TiO2)5/M2C composites just from the knowledge of the MXene composition. It is likely that the present trends hold for other TiO2/MXene composites.
Guest selectivity of [Ni2] supramolecular helicates
(Royal Society of Chemistry, 2024-06-29) Imperato, Manuel; Nicolini, Alessio; Ribas Ariño, Jordi; Antkowiak, Michal; Roubeau, Olivier; Cornia, Andrea; Novikov, Valentin; Barrios Moreno, Leoní Alejandra; Aromí Bedmar, Guillem
Two new paramagnetic supramolecular helicates with the formula (X@[Ni2L3])3+ (X = Cl, or Br; L = a bis-pyrazolylpyridine ligand) have been prepared and are described. Helicates of this metal are very rare with virtually no prior examples of them acting as hosts of anionic species. The persistence of the new assemblies in solution has been demonstrated unambiguously by mass spectrometry and paramagnetic 1H NMR. This has allowed us to establish the preference of the coordination [Ni2] host for Cl− over Br−, in agreement with DFT calculations. These results show the promise of the use of metallohelicates as suitable systems for the selective encapsulation of specific anions in solution.
Copper- and manganese-based layered hybrid organic–inorganic compounds with polymorphic transitions as energy storage materials
(Royal Society of Chemistry, 2024-06-28) Salgado Pizarro, Rebeca; Puigjaner Vallet, Ma. Cristina; García-Arch, Josué; Fernández Renna, Ana Inés; Barreneche, Camila
Solid–solid phase change materials (ss-PCM) have emerged as a promising alternative to traditional methods of thermal regulation, such as solid–liquid transformations. Due to their wide operational temperature range and competitive performance, ss-PCM materials are increasingly being explored for their potential in cooling electronic devices. Here, we explore the potential of layered hybrid organic–inorganic perovskites (LHOIPs) as thermal energy storage materials for passive cooling applications. Two formulations, bis(dodecylammonium) tetrachlorocuprate(II) (CuC12) and bis(dodecylammonium) tetrachloromanganate(II) (MnC12) were synthesised and comprehensively characterised. The analyses revealed that these materials present a two-dimensional structure with a triclinic conformation at 100 K. Notably, both materials exhibited a polymorphic transformation with low thermal hysteresis (1.3–2.5 K). These findings indicate that these materials hold significant potential as thermoregulator materials in cooling electronics. Furthermore, both CuC12 and MnC12 demonstrated good thermal stability compared to other types of ss-PCM. Overall, the findings of this study suggest that LHOIPs, particularly CuC12 and MnC12, are promising candidates for further exploration as thermal energy storage materials in electronic cooling applications.
Rational design of organic diradicals with robust high-spin ground state based on antiaromatic linkers
(Royal Society of Chemistry, 2024-11-21) Santiago, Raul; Carvajal Barba, M. Àngels; Poater i Teixidor, Jordi; Moreira, Ibério de Pinho Ribeiro; Bromley, Stefan Thomas; Deumal i Solé, Mercè; Ribas Ariño, Jordi
Fully-organic molecules with high-spin ground states are promising building blocks for new lightweight flexible magnetic materials for emerging technological applications (e.g. spintronics). In this study, we explore the potential of diradicals made of two diphenylmethyl-based open-shell cores covalently linked via different types of pentalene and diazapentalene-based antiaromatic couplers (including dibenzopentalenes and acene-inserted derivatives). Accurate electronic structure calculations have been employed to target non-bonding and non-disjoint frontier molecular orbitals that favor high-spin configurations, leading to the identification of diradicals displaying robust triplet ground states. These candidates exhibit singlet-triplet energy gaps that are up to ten times the thermal energy at room temperature. These substantial gaps emerge from strong interactions between the p-systems of the open-shell centers and the antiaromatic coupler. These interactions not only result in high spin states but are also found to lead to an enhanced stability of the diradicals by drastically dampening their inherent antiaromatic character as compared to the bare couplers, and promoting a high degree of spin density delocalization. These findings highlight the potential of pentalene-based diradicals as building blocks for developing new advanced fully organic magnetic materials.
Gas-Phase Production of Hydroxylated Silicon Oxide Cluster Cations: Structure, Infrared Spectroscopy, and Astronomical Relevance
(American Chemical Society, 2024-06-20) Donato, Andreu A. de; Ghejan, Bianca-Andreea; Bakker, Joost M; Bernhardt, Thorsten M.; Bromley, Stefan Thomas; Lang, Sandra M.
The interaction of free cationic silicon oxide clusters, SixOy+ (x = 2–5, y ≥ x), with dilute water vapor, was investigated in a flow tube reactor. Product mass distributions indicate cluster size-dependent dissociative water adsorption. To probe the structure and vibrational spectra of the resulting SixOyH2+ (x = 2–4) clusters, we employed infrared multiple photon dissociation spectroscopy and density functional theory calculations. The planar rhombic cluster core of the disilicon oxides (x = 2) appears to be retained upon dissociative adsorption of one H2O unit, whereas a significant structural transformation of the tri- and tetra-silicon oxides (x = 3 and 4) is induced, resulting in an increased coordination of the Si atoms and more 3D cluster structures. In an astronomical context, we discuss the potential relevance of SixOyHz+ clusters as seeds for dust nucleation and catalysts for carbon-based chemistry in diffuse or translucent interstellar clouds, where all the necessary conditions for producing these species are found. In the produced clusters, the frequency of the isolated silanol Si–OH stretching vibrational mode is considerably blue-shifted compared to that in hydroxylated bulk silica and small inorganic compounds. This mode has a characteristic frequency range between 1200 cm–1 (8.3 μm) and 1090 cm–1 (9.2 μm) and is associated with the anomalously small Si–OH bond lengths in these ionised species. In infrared observations such high frequency Si–O stretching modes are usually associated with a pure bulk silica component of silicate cosmic dust. The presence of SixOyH2+ clusters in low silica astrophysical environments could thus potentially be detected via their signature Si−O band using the James Webb space telescope.
Coupling wastewater treatment with fuel cells and hydrogen technology
(Elsevier B.V., 2024-04-25) Alcaide Fernández de Vega, Fernando; Sirés Sadornil, Ignacio; Brillas, Enric; Cabot Julià, Pere-Lluís
Fuel cells (FCs) and hydrogen technologies are emerging renewable energy sources with promising results when applied to wastewater treatment (WWT). These devices serve not only for power generation, but some specific FCs can also be employed for degradation of pollutants and synthesis of intermediates needed in WWT. Microbial FCs are potent devices for WWT, even containing refractory pollutants. Despite being a nascent technology with high capital expenses, the use of cost-effective materials, reduction of operational cost, and increased generation of energy and value-added chemicals such as hydrogen will facilitate the market penetration through selected niches and hybridization with alternative WWT technologies.
Stable 1,3,2-Benzodithiazolyl Radicals: Modification ofReactivity, Crystal Packing, and Solid State MagneticProperties by Fluorination
(Wiley-VCH Verlag, 2026-02-26) Buravlev, Alexander A.; Makarov, Alexander Yu.; Ribas Ariño, Jordi; Carvajal Barba, M. Àngels; Deumal i Solé, Mercè; Balmohammadi, Yaser; Grabowsky, Simon; Shundrina, Inna K.; Zakharov, Boris A.; Irtegova, Irina G.; Uvarov, Mikhail N.; Bogomyakov, Artem S; Bagryanskaya, Irina Yu.; Shundrin, Leonid A.; Zibarev, Andrey V.
Impact of fluorination on crystal and molecular structure, heteroatom reactivity, and solid-state magnetic properties of thermally-stable π-radicals is studied experimentally and computationally with 1,3,2-benzodithiazolyl 1· and its 4,7-difluoro, 4,5,6,7-tetra-fluoro, and 4,7-difluoro-5,6-(hexafluoropropane-1,3-diyl) derivatives 2-4, respectively. Radicals 2 -4 are isolated by vacuum thermolysis of their unusual covalent 2:1 adducts with 7,7,8,8-tetracyanoquinodimethane. The impact of fluorination on reactivity is evidenced by transformation of 2-4 and 2 +-4 + into corresponding 2H-1-oxo-1,3,2-benzodithiazoles under the influence of air’s or solvents’ moisture; back transformation into the cations under the action of protic acids; and formation of a paramagnetic molecular complex between 3 and naphthalene, whereas 1 and octafluoronaphthalene do not exhibit complexation. The crystal structures of 3 and 4 reveal a novel packing motif featuring radical pairs linked by four-center interactions that stack into offset π-columns, forming a unique zip-π-stack synthon that incorporates head-over-tail π-pairs of radicals. Despite the formation of π-pairs, polycrystalline 3 and 4 display a nonzero effective magnetic moment that rises with temperature above 200 K, although the values remain significantly lower than those of the high-temperature polymorphs of magnetically-bistable 1 and 2·. This behavior can be rationalized by different magnetic topologies and values of spin exchange between the radicals.
Engineered SnO 2/BiOI fibers via electrospinning for robust visible-light/peroxymonosulfate -driven multipollutant mineralization
(Elsevier B.V., 2026-03-01) Huidobro, Laura; Allés, Miquel; Abid, Mahmoud; Bechelany, Mikhael; Sousa Romero, Carmen; Gómez, Elvira; Serrà i Ramos, Albert
Engineered photocatalysts capable of operating under visible light and realistic water matrices are needed to address emerging pharmaceutical contaminants. Here, we fabricate SnO2/BiOI fibrous heterostructures by electrospinning SnO2 nanofibers decorated with solvothermally synthesized BiOI followed by calcination. The electrospun fibers provide a mechanically robust, high-surface-area scaffold, while BiOI incorporation enhances visible-light absorption and creates SnO2/BiOI heterointerfaces. Textural, optical, and spectroscopic analyses reveal progressive surface decoration, increased surface area, and defect-rich Bi environments as BiOI loading increases. Using tetracycline (TC) as a model contaminant at neutral pH, SnO2/BiOI composites markedly outperform pristine SnO2 under visible light and/or peroxymonosulfate (PMS), with an optimal BiOI content (SBO2) under single-stimulus conditions and near-complete TC mineralization for the highest loading (SBO3) in the PMS + visible-light system. Radical scavenging indicates that SO4•− and •OH are the dominant reactive species, with O2•−, h+ and e− playing secondary roles. A multipollutant mixture (TC, sulfamethoxazole, levofloxacin, lansoprazole) is mineralized by >80% in both Milli-Q and tap water, and SBO3 retains high activity over nine cycles with Bi and I leaching below 0.05% after 48 h. Density functional theory calculations, combined with XPS, support an S-scheme SnO2/BiOI heterojunction, enabling spatial separation of strongly reducing electrons in BiOI and oxidizing holes in SnO2. Although high PMS loadings can partially mask intrinsic catalyst differences, these results outline a practical design platform for heterogeneous (slurry), visible-responsive, PMS-assisted photocatalysts for pharmaceutical-laden effluents.
Roadmap for animate matter
(ART AMB B, 2025-08-13) Guix Noguera, Maria
Humanity has long sought inspiration from nature to innovate materials and devices. As science advances, nature-inspired materials are becoming part of our lives. Animate materials, characterized by their activity, adaptability, and autonomy, emulate properties of living systems. While only biological materials fully embody these principles, artificial versions are advancing rapidly, promising transformative impacts in the circular economy, health and climate resilience within a generation. This roadmap presents authoritative perspectives on animate materials across different disciplines and scales, highlighting their interdisciplinary nature and potential applications in diverse fields including nanotechnology, robotics and the built environment. It underscores the need for concerted efforts to address shared challenges such as complexity management, scalability, evolvability, interdisciplinary collaboration, and ethical and environmental considerations. The framework defined by classifying materials based on their level of animacy can guide this emerging field to encourage cooperation and responsible development. By unravelling the mysteries of living matter and leveraging its principles, we can design materials and systems that will transform our world in a more sustainable manner.
Understanding the Chemical Bond in Semiconductor/MXene Composites: TiO2 Clusters Anchored on the Ti2C MXene Surface
(Wiley-VCH, 2024-02-22) García-Romeral, Néstor; Keyhanian, Masoomeh; Morales García, Ángel; Viñes Solana, Francesc; Illas i Riera, Francesc
First-principles calculations on titania clusters (TiO2)n (n=5 and 10) supported on the pristine Ti2C (0001) surface were carried out to understand the properties of semiconductor/MXene composites with implications in (photo)-catalysis. The reported results reveal a high exothermic interaction accompanied by a substantial charge transfer with a concomitant, notorious, deformation of the titania nanoclusters. The analysis of the density of states analysis of the composite systems evidences a metallic character with titania related states crossing the Fermi level. The picture of the chemical bonds is completed by the analysis of X-Ray Photoelectron Spectra (XPS) features, evidencing clear shifts of the C(1s) and O(1s) related peaks relative to the isolated systems that have a quite complex origin. This detailed analysis provides insights to experimentalists interested in the design and synthesis of these systems with possible applications in catalys
Superhydrophobic FeNi3/Al2O3 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.

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