Articles publicats en revistes (Enginyeria Química i Química Analítica)

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Phosphorus recovery via vivianite precipitation in anaerobic digestion and fermentation processes: A comprehensive review
(Elsevier B.V., 2025-10-13) Aguilar-Pozo, V.B.; Tamayo, P.; Casallas-Ojeda, Miguel; Siscar, E.; Fonoll, X.; Chimenos Ribera, Josep Ma.; Astals Garcia, Sergi
Phosphorus recovery is gaining importance due to its supply risk. Wastewater treatment plants (WWTPs) are sinks of phosphorus from municipal and industrial discharges, making them ideal sites for recovery. In WWTPs, the dosage of FeCl3 favours spontaneous formation of vivianite (Fe3(PO4)2⋅8H2O). The optimal Fe:P molar ratio and pH are 2.5:1 and 7–9, respectively. These conditions can achieve phosphate recoveries as vivianite of 70–90 % after the anaerobic digestion (AD) stage. Nonetheless, excessive addition of iron ions and/or vivianite formation in AD can hinder organic matter degradation and lower biogas yields. Anaerobic fermentation (AF) and seeding have enhanced phosphorus recovery yields. The former mobilises more phosphorus and iron into the soluble fraction, while the latter promotes larger crystal sizes by reducing the supersaturation demand. Vivianite precipitation is a promising technology for phosphorus recovery due to its potential applications in industry and agriculture, all while supporting the circular economy. This literature review provides a comprehensive overview of current knowledge on vivianite precipitation in WWTPs, including detection and quantification methods. It also identifies key disadvantages of vivianite formation in WWTPs and provides valuable recommendations for future research.
Honey geographical origin characterization and authentication based on spectrophotometric assays, physicochemical parameters and LC-MS/MS polyphenolic profiling
(MDPI, 2025-11) Mostoles, Danica; de Krijger, Fleur; Mara, Andrea; Sanna, Gavino; Saurina, Javier; Sentellas, Sonia; Núñez Burcio, Oscar
Honey is a highly consumed natural sweetener produced by honeybees from the nectar of plants, secretions of living parts of plants, or insect excretions. Its high value is due to its nutritional value and multiple benefits to human health. However, due to the diversity in geographical origins, the properties of honey can vary depending on the region of production, leading to discrepancies in honey pricing. Therefore, it is essential to examine these variations by analyzing several parameters in honey from diverse regions. In this work, honeys from 8 countries were characterized by measuring several physicochemical parameters and spectrophotometric assays aiming at geographical origin authentication. In addition, the polyphenolic profile of the samples was obtained by LC-LRMS. An acceptable discrimination of the samples was obtained when considering all variables altogether, with classification errors lower than 31.9%.
Nixtamalization of maize to reduce mycotoxin exposure: a human biomonitoring intervention study in Soweto, South Africa
(MDPI, 2025-10-25) Njobeh, Patrick B.; De Saeger, Sarah; Maris, Elias; Ndlangamandla, Palesa; Adelusi, Oluwasola A.; Akinmoladun, Oluwakamisi F.; Odukoya, Julianah O.; Fagbohun, Richard T.; Oyeyinka, Samson A.; Sekhejane, Palesa; Peró Gascón, Roger; De Boevre, Marthe; Croubels, Siska
Mycotoxin contamination is a global threat to food safety and human health, especially in regions facing food insecurity, such as Sub-Saharan Africa. This intervention study evaluates the effectiveness of nixtamalization, a traditional alkaline cooking method, in reducing mycotoxin levels in maize and corresponding urinary biomarkers of exposure. Forty adult healthy volunteers from an informal settlement in Kliptown, Soweto (South Africa), were randomly assigned to consume control maize or visibly moldy maize subjected to nixtamalization. Nixtamalization achieved a reduction of fumonisin B3 and deoxynivalenol (DON) to unquantifiable or undetectable levels in maize, while reducing fumonisin B1 (FB1), fumonisin B2, and zearalenone (ZEN) by 95%, 95%, and 89%, respectively. Aflatoxin B1 was unquantifiable before and eliminated after treatment. Biomarker analysis revealed that after consumption of either control or nixtamalized maize, urinary levels of FB1, ZEN, and its metabolites α- and β-zearalenol (α- and β-ZEL) did not show significant differences between groups (p>0.05). DON and tenuazonic acid levels were not affected by the intervention (p>0.05), with urinary detection frequencies remaining above 90%. These results demonstrate nixtamalization effectively lowers mycotoxin levels in maize, resulting in exposure levels comparable to control maize, and highlight human biomonitoring as a sensitive tool for evaluating food safety interventions.
Determination of dyes in candies in an analytical chemistry laboratory subject
(Omnia Science, 2025) Carrera, Laura; Serraïma, Dídac; Bagán Navarro, Héctor
The use of everyday life samples in laboratory subjects enhances motivation among students and, therefore, improves their learning outcomes. Candies are a common sample in students’ everyday life, which makes their dye content an interesting analyte to determine. Food dyes are usually found in candies to increase their attractiveness by providing a bright, intense colour. Their determination is interesting due to increasing concerns in society about the use of food additives. Therefore, this learning experience aims to quantify the content of food dyes in candy samples by UV-Vis spectrometry, taking advantage of their intrinsic colour. For this determination, students need to extract the dye from the candy, take the solution to an appropriate volume and measure the absorbance. Using the external calibration curve method, students calculate the dye concentration and then use this information to compare it with the limits established by the legislation. During this practical, students have optimized the experimental procedure, addressing the different problems that appeared. Also, several points were detected as good learning opportunities to discuss important aspects of the analytical chemistry. From this practical, students learn about the UV-Vis spectrometry technique, improve their practical skills of laboratory working and enhance their critical reasoning and information searching skills. This enables students to contextualize the analysis performed by understanding the importance of a concentration value obtained to solve a real problem and makes the acquired knowledge more significant, profound and constructive.
LC-HRMS Fingerprinting and Chemometrics for the Characterization and Classification of Lotus Cultivars from Uruguay: A Study on Phenolic Composition
(Frontiers Media, 2025-08) Olivaro, Cristina; Núñez, Nerea; Basile, Patricia; Mederos, América; Reyno, Rafael; Saurina, Javier; Núñez Burcio, Oscar
Introduction: The Lotus genus, part of the legume family, comprises over 180 species distributed across diverse ecosystems worldwide. Its broad genetic diversity enables adaptation to various environmental conditions and represents a valuable resource for breeding programs targeting key agronomic traits. One of the most attractive features of Lotus species is the presence of condensed tannins in the forage, which, in ruminants, help prevent bloat, exhibit antiparasitic properties, enhance the absorption of non-ammonia nitrogen compounds, and reduce greenhouse gas emissions. Aims and methods: This study aimed to develop a UHPLC-HRMS method for classifying ten Lotus cultivars produced in Uruguay using a non-targeted metabolomic fingerprinting approach. Five cultivars belong to Lotus corniculatus, three to Lotus uliginosus, and two are interspecific hybrids. The analysis focused on phenolic compound-rich fingerprints. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used for data exploration and classification, and to identify key phenolic compounds with high discriminant potential. Finally, cultivar-specific polyphenolic compounds were tentatively identified based on chromatographic and high-resolution mass spectrometry (HRMS/MS) data obtained from all cultivars. Results: When defining four classes (L. uliginosus, L. corniculatus, and the two hybrids), the optimal PLS-DA model required six latent variables and achieved 100% classification accuracy, with both sensitivity and specificity reaching 100%. Additional PLS-DA models were developed to assess intra-species discrimination among the 3 L. uliginosus and 5 L. corniculatus cultivars, with varying degrees of separation observed. In each PLS-DA model, VIP loadings scores allowed the selection of the most discriminant phenolic compounds for each class under study. A total of 105 compounds, including phenolic acids, flavonols, flavan-3-ols, proanthocyanidins, and organic acids, were tentatively identified by analyzing all cultivars.
Acid dissociation constants in selected dipolar non-hydrogen-bond-donor solvents (IUPAC Technical Report)
(International Union of Pure and Applied Chemistry., 2025-12-01) Leito, Ivo; Kaljurand, Ivari; Piirsalu, Mare; Tshepelevitsh, Sofja; Zheng, Jonathan W.; Rosés Pascual, Martí; Gal, Jean-François
This compilation includes more than 9000 pK a values determined in seven dipolar non-hydrogen-bond-donor solvents {dimethyl sulfoxide, acetonitrile, N,N-dimethylformamide, pyridine, acetone, 4-methyl-1,3-dioxolan-2-one (propylene carbonate), oxolane (tetrahydrofuran)} for close to 5000 acids collected from around 800 original works published during the last 60 years. The data have been critically evaluated on the basis of defined quality criteria and depending on situation, kept as they were originally published, marked as doubtful/unreliable (around 2700 values) or corrected (around 2400 values). To enable automated processing and mining, the data are presented as a set of spreadsheets, together with structural codes (SMILES and InChI strings), compound class qualifiers, and comments. The document contains also comprehensive educational background information on the acid-base processes in non-aqueous media, as well as brief descriptions of the main measurement methods, with focus on the reliability of the data and sources of uncertainty. The full dataset is available at the permanent address https://doi.org/10.5281/zenodo.12608876.
An FIA-MS Method for Rapid Coffee Adulteration Detection: A Comparative Study with a Non-Targeted LC-MS Approach
(MDPI, 2025-08) Núñez Burcio, Oscar; Núñez, Nerea; Saurina, Javier
Coffee adulteration is a growing concern in the food industry due to economic and quality implications. This study evaluates a rapid, non-targeted fingerprinting method based on flow injection analysis–mass spectrometry (FIA-MS) for detecting common coffee adulterants. A total of 119 samples were analyzed, including 43 coffee samples and 76 samples of common coffee adulterants (16 chicory, 10 barley, and 50 flour samples). FIA-MS combined with chemometric analysis allowed for the classification of pure and adulterated coffee samples with over 95% accuracy. Compared to LC-MS, the FIA-MS method showed a similar performance while offering significantly faster analysis and lower solvent consumption, making it a practical and sustainable option for high-throughput screening. For PLS regression studies, calibration and prediction errors were consistently below 0.91% and 11.7%, respectively. Furthermore, the methodology was compared with a non-targeted LC-MS approach, showing an excellent performance.
Cobalt ferrite magnetic nanoparticles as stirring actuators to improve UV–Vis spectroelectrochemical measurements in normal reflection mode.
(Springer Verlag, 2025-08-01) Cutillo‑Foraster, Alessandra; Özbek, Nurhayat; Otero‑de-Muller, Lluís; Bastos-Arrieta, Julio; Serrano i Plana, Núria; Díaz Cruz, José Manuel
Spectroelectrochemical (SEC) measurements using UV–Vis radiation in normal reflection mode (or normal configuration)are less sensitive than parallel approaches, since the volume of sample monitored has a much lower proportion of the diffusionlayer created by the electrochemical processes, i.e., the region where relevant optical changes take place. In contrast,the normal configuration is more robust and reproducible and, as of today, is the only commercially available. This workpresents a strategy to enhance normal reflection SEC measurements of Fe(III)/(II)-orthophenanthroline system using ascreen-printed carbon electrode (SPCE), improving competitiveness with parallel designs. This method required the designof a new measuring cell based on the geometry of the commercial one, but replacing the eight magnets by a non-magneticclosing system. The developed approach involves adding cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) to theanalyte solution and coupling the SEC cell to a conventional magnetic stirrer. The resulting nanostirring, driven by MNPsmovement, enhances mass transport toward the electrode. This accelerates diffusion layer renewal, leading to a noticeableincrease of both electrochemical and optical signals.
Selective molecular probes for G-quadruplex and G-quadruplex–duplex junctions: Cyanine dye interactions and structural insight
(Elsevier B.V., 2025-09-01) Vasilev, Aleksey; Cheshmedzhieva, Diana; Ahmed, Hamzah; Raset Vidal, Ona; Borgonovo, Gigliola; Mazzini, Stefania; Artali, Roberto; Zuccolo, Marco; Gargallo Gómez, Raimundo
There is growing interest in hybrid DNA structures, particularly G-quadruplex–duplex junctions, as potential ligand binding sites. In this work, we investigate the interaction of two cyanine dyes (R9 and 3b), which differ in hydrophilicity, with various DNA structures, including duplex DNA, parallel and antiparallel G-quadruplexes, and a G-quadruplex-duplex junction. We employed molecular spectroscopic techniques (UV–visible absorption, circular dichroism, fluorescence), nuclear magnetic resonance (NMR) spectroscopy, multivariate analysis, and molecular docking studies. UV–visible absorption and circular dichroism provided insights into dye aggregation and the overall interaction modes, while NMR and docking yielded structural details. The results reveal that the two dyes exhibit distinct interactions with the studied DNA structures due to their differing behaviors in aqueous solution. The less polar 3b dye is aggregation-prone and prefers π-stacking with the terminal tetrads in the parallel G-quadruplex structure, leading to strong induced circular dichroism in the visible region and fluorescence responses toward parallel G-quadruplex. The more polar R9 dye forms defined non-stacking complexes, especially at structured duplex or G-quadruplex-duplex junction sites, showing selective fluorescence enhancement. NMR and molecular docking support the idea that R9 binds selectively and without aggregation, while 3b binds strongly and non-specifically, often resulting in precipitation.
Bioaggregachromism of Asymmetric Monomethine CyanineDyes as Noncovalent Binders for Nucleic Acids
(MDPI, 2025-03-14) Ilieva, Sonia; Petkov, Nikolay; Gargallo Gómez, Raimundo; Novakov, Christo; Ragelow, Miroslav; Todorova, Nadezhda; Vasilev, Aleksey; Chesmedzhieva, Diana
Two new asymmetric monomethine cyanine dyes, featuring dimethoxy quinoliniumor methyl quinolinium end groups and benzothiazole or methyl benzothiazole endgroups were synthesized. The chemical structures of the two dyes—(E)-6,7-dimethoxy-1-methyl-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium iodide (3a) and(E)-4-((3,5-dimethylbenzo[d]thiazol-2(3H)-ylidene)methyl)-1,2-dimethylquinolin-1-ium iodide(3b)—were confirmed through NMR spectroscopy and MALDI-TOF mass spectrometry.A new methodology was developed to study monocationic dyes in the absence of amatrix and cationizing compounds in MALDI-TOF mass experiments. The newly synthesizeddyes contain hydrophobic functional groups attached to the chromophore, enhancingtheir affinity for the hydrophobic regions of nucleic acids within the biological matrix. Thedyes’ photophysical properties were investigated in aqueous solutions and DMSO, as wellas in the presence of nucleic acids. The dyes exhibit notable aggregachromism in both pureaqueous and buffered solutions. The observed aggregation phenomena were further elucidatedusing computational methods. Fluorescence titration experiments revealed that uponcontact with nucleic acids, the dyes exhibit bioaggregachromism–aggregachromism on thesurfaces of the respective biomolecular matrix (RNA or DNA). This bioaggregachromismwas further confirmed by CD spectroscopy. Given the pronounced aggregachromismdetected, we conclude that the dyes investigated in this study are highly suitable for useas fluorogenic probes in biomolecular recognition techniques. The unique absorption andfluorescence spectra of these dyes make them promising fluorogenic markers for variousbioanalytical methods related to biomolecular recognition.
Assessing sorption of fluoroquinolone antibiotics in soils from a Kdcompilation based on pure organic and mineral components
(Elsevier, 2024-05-30) Fabregat-Palau, Joel; Rigol Parera, Anna; Grathwohl, Peter; Vidal Espinar, Miquel
The presence of fluoroquinolone (FQ) antibiotics in soils may cause a threat to human health due to overexposure and the generation of antibiotic resistance genes. Understanding their sorption behavior in soils is important to predict subsequent FQ (bio) availability. Here, FQ sorption in pure soil organic (i.e., humic substances) and mineral (i.e., metal oxides; phyllosilicates) components is evaluated through a solid-liquid distribution coefficient (Kd (FQ)) dataset consisting of 243 entries originated from 80 different studies, to elucidate their respective contribution to the overall Kd (FQ) in bulk soils. First, different factors affecting FQ sorption and desorption in each of these soil phases are critically discussed. The strong role of pH in Kd (FQ), due to the simultaneous effect on both FQ speciation and surface charge changes, encouraged the derivation of normalized sorption coefficients for the cationic, zwitterionic and anionic FQ species in humic substances and in different phyllosilicates. Kd (FQ) in metal oxides revealed a key role of metal nature and material specific surface area due to complexation sorption mechanisms at neutral pH. Cumulative distribution functions (CDF) were applied to each dataset to establish a sorption affinity range for each phase and to derive best estimate Kd (FQ) values for those materials where normalized sorption coefficients to FQ species were unavailable. The data analysis conducted in the different soil phases set the basis for a Kd (FQ) prediction model, which combined the respective sorption affinity of each phase for FQ and phase abundance in soil to estimate Kd (FQ) in bulk soils. The model was subsequently validated with sorption data in well characterized soils compiled from the literature.
Laser-Induced Surface Vitrification for the Sustainable Stabilization of Copper Tailings
(MDPI, 2025-06-20) Sáez-Navarrete, César; Baraza, Xavier; Ramos-Grez, Jorge; Sans Mazón, Carme; Arauzo, Claudia; Coca, Yoandy
This study introduces CO2 laser surface vitrification as an innovative method for managing copper mining tailings, offering a sustainable solution to critical challenges in mineral processing. This technique transforms tailings into a stable and impermeable layer, immobilizing hazardous metals contained within them. By achieving vitrification at the surface level and operating at temperatures around 1200 °C, the process significantly reduces energy consumption compared to traditional vitrification methods, making it suitable for large-scale applications in remote mining sites. Detailed geochemical and mechanical analyses confirmed the formation of a dense vitreous matrix with high hardness (7.19–7.48 GPa) and reduced permeability, ensuring compliance with stringent environmental regulations. However, the brittle nature of the vitrified layer underscores the need for further research to enhance mechanical resilience. This work positions CO2 laser vitrification as a transformative approach for integrating energy-efficient technologies into mineral processing, addressing key environmental concerns while advancing the sustainable management of mining waste.
Meat authentication based on animal species and other quality meat attributes (protected geographical indication, organic production, and Halal and Kosher products) by HPLC-UV fingerprinting and chemometrics
(Springer Science + Business Media, 2025-06-11) Santomá Martí, Alexandra; Aijon, Nil; Núñez Burcio, Oscar
A simple and economic high-performance liquid chromatography with UV-vis detection (HPLC-UV) metabolomic fingerprinting methodology was developed and applied after a water extraction procedure to obtain sample chemical descriptors suitable for meat authentication by chemometrics. 300 meat samples involving different species (lamb, beef, pork, rabbit, quail, chicken, turkey, and duck) as well as different non-genetic attributes (protected geographical indications, organic production, and Halal and Kosher meats) were analyzed, and the obtained HPLC-UV fingerprints subjected to PCA and PLS-DA for classification and authentication. Excellent PLS-DA discrimination and classification performance was accomplished for calibration and cross-validation, with sensitivity and specificity values higher than 100% and 99.3%, respectively, and classification errors below 0.4%, when meat species were considered. The prediction capability when employing a classification decision tree consisting on consecutive dual PLS-DA models built using a hierarchical model builder was of 100% accuracy when 48 meat samples were subjected to the model as unknown samples. Multiclass PLS-DA classification performances when addressing meat geographical origin, organic productions and Halal and Kosher products were also very acceptable, with overall sensitivity and specificity values higher than 91.2%, and classification errors below 6.9%. Finally, fraudulent meat adulteration cases involving PGI, organic and Halal and Kosher adulterated meats were evaluated by partial least squares (PLS) regression, allowing the detection and quantitation of adulteration levels within the range from 15-85% with prediction errors below 6.6%, demonstrating the suitability of the proposed methodology to assess meat authenticity.
Determination of chromium(VI) with screen-printed ex-situ bismuth film electrodes by adsorptive stripping voltammetry
(Wiley-VCH, 2025-01-01) Triviño, Juan José; Esteban i Cortada, Miquel; Díaz Cruz, José Manuel; Serrano i Plana, Núria; Alvarez-Lueje, Alejandro; Arancibia, Verónica
This work presents a fast and sensitive method, with an ex–situ bismuth film screen-printed carbon electrode (ex–situ Bi–SPCE), for the determination of Cr(VI) through adsorptive stripping voltammetry (AdSV) using Pyrogallol Red (PGR) ascomplexing agent. The method is based on the oxidation of PGR by Cr(VI) and posterior complexation with Cr(III). To obtaina sensitive and selective method, the effects of various parameters such as pH, ligand concentration of PGR (CPGR),accumulation potential, and accumulation time (Eacc, tacc) were optimized. The optimal conditions using Bi–SPCE preparedex–situ were pH 4.5 (0.01 molL^-1 acetic acid/acetate buffer), CPGR: 2.6 μmolL^-1, Eacc: - 0.70 V and tacc: 60 s. Peak current isproportional to Cr(VI) concentration over the range 0.23–12.0 μgL^-1, with a 3σ detection limit of 0.97 μgL^-1. The method wasvalidated by determining Cr(VI) in tap water spiked with Cr(VI) and Cr(III).
Tutorial on modelling chromatographic surrogation of biological processes
(El Sevier, 2024-11-01) Fuguet i Jordà, Elisabet; Rosés Pascual, Martí
The accurate emulation of biological partition systems through physicochemical models is crucial in pharmacology,
toxicology, and environmental science for understanding the ADMET profiles of substances. Direct
experimentation on biological systems can be long, expensive, and ethically and practically challenging, so
developing reliable physicochemical models is essential. These models help predict compound behaviour in
organisms, reduce animal testing, and streamline drug discovery and risk assessment. Chromatographic systems
are of particular interest to mimic biological or environmental processes because of its versatility, as they provide
a large number of different partition systems only by changing the nature of the mobile and stationary or
pseudostationary phases. The effectiveness of any physicochemical system in emulating biological processes is
usually evaluated through empirical correlation with biological data. However, the characterization of physicochemical
and biological systems using a common model, such as Abraham’s solvation model, allows to identify
the best physicochemical systems to surrogate particular biological or environmental processes, only by comparison
of the system constants of the models. This tutorial demonstrates how to compare, predict, and improve
the efficiency of physicochemical systems to surrogate biological or environmental ones without the need for
previous empirical correlations. Skin permeation is presented as example of chromatographic surrogation and
case study.
Voltammetric determination of salbutamol, sulfamethoxazole, and trimethoprim as anthropogenic impact indicators using commercial screen-printed electrodes
(MDPI, 2025-05-09) Huang, Jing; Bastos-Arrieta, Julio; Serrano i Plana, Núria; Díaz Cruz, José Manuel
A voltammetric method based on the use of screen-printed carbon electrodes (SPCEs) is presented for the simultaneous determination of salbutamol (SAL), sulfamethoxazole (SMX), and trimethoprim (TMP), with high sensitivity, fast response, and excellent repeatability and reproducibility. Under the optimal voltammetric conditions, the simultaneous analysis showed linear ranges of 0.3–2.5 mg L−1, 0.3–11.1 mg L−1, and 0.5–9.0 mg L−1 for SAL, SMX, and TMP, respectively, and detection limits of 83.8 μg L−1, 88.7 μg L−1, and 139.2 μg L−1, respectively. Additionally, the developed method was successfully validated by the analysis of a spiked river water sample with satisfactory recovery values in the range of 97.0–98.8%. The added value of the presented method relays in combining cost-effective disposable SPCEs with rapid analysis (<30 s), providing portable electrochemical tools for the on-site monitoring of pharmaceutical residues, which is critical for addressing contamination linked to anthropogenic activity.
Estimation of the critical micelle concentration of sodium taurocholate inintestine-relevant conditions using complimentary techniques
(Elsevier B.V., 2025-05-13) Amézqueta, Susana; Casdanova, Unai; Fuguet i Jordà, Elisabet; Ràfols Llach, Clara
Bile salts such as sodium taurocholate (NaTc) play an important role in drugs’ bioavailability due to their capacityto form micelles. These aggregates can host a wide range of drugs and enhance their solubility in biologicalfluids. The micellization process and the types of micelles formed not only depend on the surfactant, butalso on the environment (solvent, temperature, presence of other compounds, etc.). Therefore, when solubilityassays are performed it is key to ensure that micelles are present. In this work, the critical micelle concentration(CMC) of NaTc has been evaluated using three different techniques (conductometry, fluorescence and calorimetry)in water and in different biorelevant conditions (intestinal biorelevant aqueous buffers, FaSSIF-v2 andFeSSIF-v2). While conductometry is not adequate for CMC determination of bile salts, fluorescence and calorimetryoffer complementary information. CMC experiments have shown that ion strength and the presence ofmixed micelles (formed by NaTc, phosphatidylcholine and lipids) favor the micellization process and wouldimpact on the drugs bioavailability.
Natural Pyrolusite-Catalyzed Ozonation for Nanoplastics Degradation
(MDPI, 2025-05-21) Mello, Victor; Nieto-Sandoval, Julia; Dezotti, Márcia; Sans Mazón, Carme
The increasing prevalence of polystyrene nanoplastics (PSNPs) in aquatic environments poses significant risks due to their persistence and potential toxicity. Conventional water treatment methods have proven ineffective in removing these emerging pollutants, highlighting the urgent need for sustainable and efficient treatment. This study investigates the application of catalytic ozonation using natural pyrolusite (n-MnO2) and oxalic acid (OA) as a co-catalyst for the environmentally friendly degradation of PSNPs. Key operational parameters, including pH, applied ozone dose, pyrolusite dosage, and OA concentration, were systematically evaluated. Results demonstrate that the MnO2 + OA + O3 system enhances the generation of reactive oxygen species (ROS), leading to improved PSNP removal while maintaining the applied ozone dose compared to the single ozonation reaction. The highest TOC removal of 75% was achieved within 30 min of treatment under optimal conditions (pH = 4, [MnO2] = 0.5 g L−1, [OA] = 10 mg L−1, and ozone dose of 37.5 mg min−1), with significant turbidity reduction, indicating both chemical and physical degradation of PSNPs. Catalyst reusability after three consecutive cycles confirmed minimal loss in activity, reinforcing its potential as a sustainable catalytic system. These findings highlight natural MnO2-driven catalytic ozonation as a green and effective strategy for nanoplastic removal in water treatment applications.
Adsorption of benzophenone-3 and octocrylene UV filters on polyethylene:analysis by HPLC-MS/MS and voltammetry with screen-printed electrodes
(Elsevier B.V., 2025-05-15) Contreras Llin, Albert; Palape Oxa, Mariana; Díaz Cruz, José Manuel; Serrano i Plana, Núria; Díaz Cruz, Silvia
Microplastics (MPs) are persistent pollutants that can adsorb contaminants, facilitating their accumulation inaquatic ecosystems. The presence of UV filters (UVFs) such as benzophenone-3 (BP3) and octocrylene (OC),exacerbates this issue, particularly in coastal areas. This study presents an innovative dual-method approachcombining high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and differentialpulse adsorptive stripping voltammetry (DPAdSV) to assess the adsorption of UVFs on polyethylene (PE), awidely found polymer in aquatic environments. Adsorption kinetics were analysed using pseudo-first-order(PFOM) and pseudo-second-order (PSOM) models, revealing a higher equilibrium sorption capacity for OCdue to its stronger hydrophobic interactions with PE. A central composite design (CCD) was employed to enhanceresources efficiency in experimentation and controlled experiments exposed the materials to both pure freshwater and synthetic seawater. The results indicate a higher adsorption affinity of OC on PE than BP3, attributedto its high octanol-water partition coefficient (log Kow 6.88) and stronger hydrophobic interactions. Exposuretime was the most influential variable across both media, while pH and temperature had a significant effect onBP3 adsorption in synthetic seawater. Hydrophobic partitioning, aided by van der Waals forces, was identified asthe dominant interaction mechanism for both UVFs, with π–π and electrostatic interactions playing minimal rolesdue to the nature of the polymer. The study provides new insights into how polymer–pollutant interactions varyacross environmental conditions and offers a novel voltammetric alternative for in-situ UVFs monitoring.
Influence of Ionization and the Addition of Cyclodextrins andHydrophilic Excipients on the Solubility of Benzthiazide,Isoxicam, and Piroxicam
(MDPI, 2025-04-25) Lucero Borja, Diego Sebastián; Ruiz, Rebeca; Fuguet i Jordà, Elisabet; Ràfols Llach, Clara
Background: The bioavailability of a drug depends, among other parameters,on solubility. One of the strategies used to enhance the solubility of sparingly solubledrugs is the use of excipients. Excipients can interact with the drug by increasing its solubilityand/or stabilizing supersaturated solutions. Some of the most common excipientsare cyclodextrins and hydrophilic polymers. Objectives: The effect of two cyclodextrins(captisol and cavasol) and three hydrophilic polymers (klucel, kollidon and plasdoneS630) on the solubility of three ionizable drugs (benzthiazide, isoxicam, and piroxicam) isevaluated at biorelevant pH values, using two complementary techniques. Methods: Thesolubility enhancement was evaluated by the comparison of the solubility with and withoutthe presence of excipients through the shake-flask and CheqSol methodology. Results:Captisol and cavasol slightly increase the concentration of the neutral species of the drugsin the solution before precipitation begins, although they do not enhance the supersaturationduration nor the thermodynamic solubility of the drugs. The increase in solubilityin the presence of cyclodextrins is mainly caused by the ionization state of the drug. Hydrophilicpolymers not only improve thermodynamic solubility but also the extent andthe duration of the supersaturation. Some metastable forms are observed for benzthiazideand isoxicam in the presence of kollidon and plasdone S630. Conclusions: The shake-flaskmethod enabled the evaluation of thermodynamic solubility both in the absence and presenceof excipients. Meanwhile, the CheqSol method provided insights into the presenceof supersaturated solutions. Different behavior is observed depending on the nature ofthe excipient.

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