Artículos (Ingeniería Química y Ambiental)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/11382

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Nanosilica synergy: unveiling the strength and fracture mechanisms in advanced concrete composites
(Consejo Superior de Investigaciones Científicas (CSIC): Instituto Eduardo Torroja, 2025) Ríos Jiménez, José David; Ruiz López, Gonzalo; González Cabrera, Dorys Carmen; Cifuentes-Bulté, Héctor; Vicente Cabrera, Miguel Ángel; Yu, Rena Chengxiang; Leiva Fernández, Carlos; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; TEP972: Mecánica de Materiales y Estructuras; TEP142: Ingeniería de Residuos
This study explores how nanosilica impacts the mechanical properties and fracture behavior of ultra-high-performance concrete (UHPC). We delved into the role of nanosilica in enhancing pozzolanic reactions and its effects on UHPC’s pore structure. This was investigated using advanced techniques such as scanning electron microscopy and mercury intrusion porosimetry. We prepared UHPC samples with varying nanosilica concentrations, replacing cement by 0 to 7.5%wt, to understand its influence comprehensively. Our findings reveal that higher nanosilica content, while beneficial in some aspects, compromises the self-compacting nature of UHPC. This necessitated conducting slump tests to evaluate workability. Remarkably, the addition of nanosilica led to a reduction in both capillary and macropores, enhancing the density and strength of the concrete. Specifically, a maximum of 5%wt nanosilica addition resulted in a 13% increase in compressive strength. However, this improvement in strength comes with a trade-off. The fracture energy of UHPC decreased by 23.2%, indicating an increase in brittleness due to nanosilica. Interestingly, tensile strength saw a 10.5% increase, primarily attributed to the enhanced formation of the C-S-H gel, a key component for concrete strength. This study illuminates the dual-edged effects of nanosilica in UHPC, presenting a nuanced view of its role in concrete technology and fracture mechanics.
The Impact of Steel Fiber Length and Dosage on Microstructure and Mechanical Performance in UHPFRC: A Hybrid Approach
(Asociación Española de Ingeniería Estructural (ACHE), 2025) Ruiz Martínez, Jaime Delfino; Ríos Jiménez, José David; Pérez-Soriano, Eva María; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Ingeniería Química y Ambiental; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España
This study evaluates the effects of steel fiber length (6 and 13 mm) and dosage on the microstructural and mechanical properties of an ultra-high-performance fiber-reinforced concrete (UHPFRC). The incorporation of 6 mm fiber significantly improved the material's workability characteristics. Microscopic evidence indicates better alignment and distribution of 13 mm fibers within the concrete matrix compared to 6 mm fibers, resulting in reduced porosity and enhanced matrix-fiber interaction. Mechanical testing confirmed that the inclu-sion of 13 mm steel fibers at various dosages consistently outperformed 6 mm fibers in enhancing compressive and flexural strengths. The optimal dosage, among those tested, for compressive strength was found to be 196 kg/m³ with 13 mm fibers, while the best performance in flexural strength was observed at 226 kg/m³. To address the challenges inherent in UHPFRC—specifically the intricate metallic fiber distri-bution and limited workability prompted a comprehensive investigation into fiber mixture optimization strategies. Hybrid fiber approach was explored by substituting 10%, 20%, and 30% of the 13 mm fiber dosage (196 kg/m³) with 6 mm steel fibers. Among these, the mix containing 80% of 13 mm steel fibers and 20% of 6 mm steel fibers demonstrated the highest flexural strength, even than those with higher steel fiber content (226 kg/m3). This hybridization suggests an optimized combination of fiber lengths for enhanced flexural performance without compromising compressive strength, providing insights into effective fiber-reinforcement strategies for UHPFRC applications.
Ultrasonic Processing and Its Impact on the Rheology and Physical Stability of Flaxseed Fiber Dispersions
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-07-25) Alfaro Rodríguez, María del Carmen; García-González, María Carmen; Muñoz García, José; Ingeniería Química
Ultrasonic homogenization is an emerging technique with significant potential to modify the structure and functionality of food ingredients. This study evaluated the effect of ultrasonic homogenization on the rheological behavior and physical stability of aqueous dispersions of flaxseed fiber. Flax mucilage, with health-promoting and techno-functional properties, is of growing interest in several industries. The samples were subjected to different ultrasonic treatments, varying in amplitude (from 40 to 100%) and duration (from 2 to 20 min), with and without preliminary rotor–stator homogenization. The rheological properties were analyzed using small-amplitude oscillatory shear (SAOS) tests and steady shear flow curves. Physical stability was assessed by multiple light scattering. The results revealed that short treatment under ultrasonic homogenization had minimal impact on the viscoelastic parameters and viscosity, regardless of the amplitude used. However, longer treatments significantly reduced both values by at least one order of magnitude or more, indicating the occurrence of microstructural degradation. The relevance of this research lies in its direct applicability to the development of functional foods, since it is concluded that control of the ultrasonic homogenization process conditions must be carefully selected to retain the desirable rheological properties and physical stability.
Techno-economic analysis of the production of n-butanol from different biomass sources
(Elsevier, 2025) Caraballo Bello, José; Rodríguez Lugo, José Luis; Baena-Moreno, Francisco M.; Vidal Barrero, Fernando; Ingeniería Química y Ambiental
This study evaluates the production of n-butanol from different biomass sources, using ethanol as an intermediate platform. The analysis considers four biomass-based production pathways: two first-generation routes, which use sugarcane and cereals (such as corn), and two second-generation routes, which utilize lignocellulosic biomass such as corn stover and wheat straw. This approach enables the comparison of different technologies in terms of efficiency and economic viability. The studied plant has a production capacity of nearly 94,000 tons of n-butanol per year, positioning it as a viable option for industrial-scale assessments. The developed models account for material and energy balances, as well as a detailed economic analysis based on indicators such as Net Present Value (NPV) and Minimum Butanol Selling Price (MBSP). Among the analyzed pathways, results show that the sugar-based pathway is the only fully profitable option under the evaluated conditions. This pathway achieves an NPV of 362 M€ and an MBSP of 954 euros per ton. Conversely, the other pathways require technological optimizations and reductions in investment costs to achieve profitability. Additionally, the sensitivity analyses conducted reveal the strong dependency of each pathway profitability on the biomass purchase price and the selling price of n-butanol itself. All in all, this study highlights the potential economic viability of n-butanol not only as a high-value-added chemical product but also as a sustainable alternative to traditional fuels, contributing to the transition towards a decarbonized economy.
Development of Acoustic Absorbent Materials Using Pine Needles
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-10-31) Ruiz Martínez, Jaime D.; Peceño, Begoña; Carrasco Carrasco, Carlos Jesús; Orejón, Daniel; Luna Galiano, Yolanda; Leiva Fernández, Carlos; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España
Acoustic absorbing materials made from waste plants or trees represent a sustainable source for noise reduction products and applications such as home acoustic insulation and/or traffic road noise reduction barriers. The primary aim of this work is hence to demonstrate the potential application of pine needle waste as the main constituent in acoustic absorbing materials while resin is used as binder. Once the samples have been manufactured, their different physical (density and porous structure), mechanical (compressive strength), and sound-insulating (sound absorption coefficient) properties are characterized. The influence of the ratio of pine needle/resin, length of the pine needle fragments, and thickness of the samples on the different properties has been explored. As the ratio of pine needles/resin increases so does the porosity, although the compressive strength decreases. To highlight this, the noise reduction coefficient is in the range of 0.67 and 0.71 (for 4 cm of thickness), which is higher than that reported for other typical sound absorption materials. An excess of resin produces a clogging phenomenon at the bottom of the samples, producing a reflective layer instead of an absorbent one, which could be used positively to increase the acoustic absorption coefficient in materials with combinations of sections with different needle/resin ratios. Owed to its low weight and high sound absorption coefficients at low frequencies (characteristic of road noise), PN finds usefulness in the manufacturing of environmentally friendly sound-absorbing materials as road insulation barriers.
Impact of solar thermal energy and calcium looping implementation on biomass gasification for low-carbon hydrogen production
(Elsevier, 2025) Aragón García, Alejandro; Villanueva Perales, Ángel Luis; González, William A.; Fuentes Cano, Diego Javier; Alonso-Fariñas, Bernabé; Gómez Barea, Alberto; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla
In the search of low-carbon hydrogen production routes, this study evaluates four biomass gasification processes: conventional steam gasification (CSG), sorption-enhanced gasification (SEG), and their solar-assisted variants (SSG and SSEG). The comparison focuses on three key aspects: hydrogen production, overall energy efficiency (to H2 and power), and carbon capture potential (generation of a pure CO2 process stream for storage or utilization). For a realistic comparison, a pseudo-equilibrium model of a double-bed gasifier was developed based on experimental correlations of char conversion under conventional and SEG conditions. The solar processes were designed for stable year-round operation, considering seasonal weather variations by appropriately dimensioning the heliostat field and the thermal and chemical energy storage systems, whose inventory dynamics were modelled. Both the gasifier and central solar tower models were rigorously validated with published data, enhancing the reliability of the results. Solar-assisted configurations significantly outperform non-solar ones in hydrogen production, with SSEG yielding 128 kg H2/ton biomassdaf compared to 90–95 kg for non-solar options. SEG demonstrates superior carbon capture potential (76 %), while solar-assisted systems achieve higher energy efficiency (67–73 % vs. 60–63 % for non-solar). These results underscore the potential of solar-assisted gasification for sustainable hydrogen production, offering enhanced yields, improved efficiency, and substantial carbon capture capabilities. Future work will involve economic and environmental analysis to determine the best overall configuration.
Homochiral imidazolium-based dicarboxylate compounds: Structure and solution behaviour
(Elsevier, 2020-12) Caballero, Pedro; Colodrero, Rosario M.P.; Conejo Argandoña, María del Mar; Pastor Navarro, Antonio; Álvarez, Eleuterio; Montilla Ramos, Francisco Javier; Carrasco Carrasco, Carlos Jesús; Nicasio, Antonio I.; Galindo del Pozo, Agustín; Química Inorgánica; Universidad de Sevilla; Junta de Andalucía; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
Treatment of (S,S)- and (R,R)-1-(1-carboxy-2-methylpropyl)-3-(1-carboxylate-2-methylpropyl)imidazolium compounds, (S,S)-HLiPr and (R,R)-HLiPr, with the appropriate base yielded sodium, ammonium and lithium salts of the corresponding chiral anion in good yields. Compounds {Na[(S,S)-LiPr]}n (1s), {Na[(R,R)-LiPr]}n (1r), {NH4[(S,S)-LiPr]}n (2s), {NH4[(R,R)-LiPr]}n (2r), {Li[(S,S)-LiPr]}n (3s) and {Li[(R,R)-LiPr]}n (3r) were characterised by analytical and spectroscopic (IR, 1H and 13C NMR and polarimetry) methods. Specifically, 1r-3r are the first examples of homochiral compounds containing imidazolium-dicarboxylate ligands that were prepared from non-proteinogenic amino acids. In solution, NMR showed dissociation and this fact was confirmed by the good agreement found between the experimental and calculated NMR chemical shifts of the [LiPr]− anion. Interestingly, a transient carbene intermediate was proposed by DFT calculations in order to explain the solution H-D exchange observed by NMR at the C2-H atom of imidazolium ring. These compounds were also characterised by single-crystal (1s,r and 2s,r) or powder diffraction methods (3s). At the solid state, they are novel one-dimensional coordination polymers in which cations are connected via chiral 2,2′-(imidazolium-1,3-diyl)bis(3-methylbutanoate) anion. For this anion, unprecedented μ4-κ2O1, κ2O3, κ1O4 coordination mode was observed in 1s.
Synthesis of α,β-Dicarbonylhydrazones by Aerobic Manganese-Catalysed Oxidation
(Wiley, 2018-07) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Álvarez, Eleuterio; Galindo del Pozo, Agustín; Química Inorgánica; Junta de Andalucía; Universidad de Sevilla
A practical, simple, and efficient manganese-catalysed oxidation of C(sp2)−H bond in readily available β-carbonylenehydrazine under aerobic conditions has been developed. This protocol exhibits a wide range of functional group tolerance in β-carbonylenehydrazines to afford α,β-dicarbonylhydrazones. Experimental and theoretical results suggest that the reaction very likely proceeds through a radical pathway via a hydrogen-atom-transfer process promoted by a MnIII species.
Molybdenum-catalyzed asymmetric sulfoxidation with hydrogen peroxide and subsequent kinetic resolution, using an imidazolium-based dicarboxylate compound as chiral inductor
(Elsevier, 2016-09-05) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Galindo del Pozo, Agustín; Química Inorgánica; Junta de Andalucía
A catalytic system based on simple and economic molybdenum compounds and a straightforwardly prepared imidazolium-based dicarboxylate compound, as chirality inductor, was developed for the catalytic asymmetric oxidation of sulfides with hydrogen peroxide. High yields of chiral methyl phenyl sulfoxide and good enantioselectivities (up to 40% ee) were achieved utilizing one equivalent of oxidant in 1 h. By combination of the enantioselective sulfoxidation and the concomitant kinetic resolution an 83% ee was obtained, an excellent enantioselectivity value for a molybdenum catalyst.
Oxodiperoxomolybdenum complex immobilized onto ionic liquid modified SBA-15 as an effective catalysis for sulfide oxidation to sulfoxides using hydrogen peroxide
(Elsevier, 2015-10) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Bobadilla Baladrón, Luis Francisco; Ivanova, Svetlana; Odriozola Gordón, José Antonio; Galindo del Pozo, Agustín; Química Inorgánica; Ministerio de Ciencia e Innovación; Ministerio de Economía y Competitividad (MINECO). España; Junta de Andalucía
A supported ionic-liquid-phase (SILP) was prepared by the reaction of 1-methyl-3-(3-(triethoxysilyl)propyl)-1H-imidazol-3-ium chloride with a mesoporous SBA-15 silica and then an oxodiperoxomolybdenum complex was immobilized onto the obtained SILP. The resulting material, identified as SBA-15 + ImCl + MoO5, was characterized by solid state NMR (1H, 13C and 29Si), and their textural and thermogravimetric properties were determined. The SBA-15 + ImCl + MoO5 material was investigated as catalyst for the oxidation of methylphenylsulfide, as model reaction, with aqueous hydrogen peroxide as oxidant at room temperature. The presence of the molybdenum species was crucial for achieving good conversions and methanol was selected as the best solvent (conversion of 95% and selectivity toward sulfoxide 98%). The optimized reaction conditions were applied for the oxidation of several selected sulfides. In general, good catalytic activity and selectivity to sulfoxide were obtained and, remarkably, the selectivity toward sulfoxide is higher than those observed in the study of the same process carried out in [C4min][PF6] (C4mim = 1–butyl-3-methylimidazolium) and catalyzed by a molecular molybdenum complex, under the same reaction conditions. The importance of the IL-functionalization in the SBA-15 material was evidenced by recycling experiments. The SBA-15 + ImCl + MoO5 catalyst was used for the sulfoxidation of the methylphenylsulfide substrate for ten reaction cycles without a significant change in conversion, selectivity to sulfoxide and molybdenum content.
Experimental and theoretical insights into the oxodiperoxomolybdenum-catalysed sulphide oxidation using hydrogen peroxide in ionic liquids
(Royal Society of Chemistry, 2014-07) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Álvarez, Eleuterio; Mealli, Carlo; Manca, Gabriele; Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
The oxidation of organic sulphides with aqueous hydrogen peroxide in ionic liquids (ILs) catalysed by oxodiperoxomolybdenum complexes was investigated. The selective formation of several sulfones was achieved using the 1 : 3 ratio of sulphide : H2O2 in [C4mim][PF6] (C4mim = 1-butyl-3-methylimidazolium) in a reaction catalysed by the [Mo(O)(O2)2(H2O)n] complex. Conversely, sulfoxides were produced with good selectivities using a 1 : 1 ratio in the same solvent in a 1 h reaction with [Mo(O)(O2)2(Mepz)2] (Mepz = methylpyrazol). The use of [C4mim][PF6] as the solvent was advantageous for two reasons: (i) the improved performance of the H2O2–IL combination; (ii) recycling of the catalyst/IL mixture without a significant diminution of conversion or selectivity. A DFT analysis using the [Mo(O)(O2)2(L)] catalysts (L = Mepz, a; 3,5-dimethylpyrazole, dmpz, b; and H2O, c) indicated that a Sharpless-type outer-sphere mechanism is more probable than a Thiel-type one. The highest barrier of the catalytic profile was the oxo-transfer step, in which the nucleophilic attack of sulphide onto the peroxide ligand occurred with formation of dioxoperoxo species. In order to yield the sulfoxide and the starting catalyst, the oxidation of the resulting dioxoperoxo species with H2O2 was found to be the most favourable pathway. Subsequently, the sulfoxide to sulfone oxidation was performed through a similar mechanism involving the [Mo(O)(O2)2(L)] catalyst. The comparable energies found for the successive two oxo-transfer steps were in agreement with the experimental formation of sulfone in both the reaction with an excess of the oxidant and the stoichiometric reaction in the absence of the oxidant. In the latter case, diphenylsulfone was isolated as the major product in the 1 : 1 combination of diphenylsulphide and [Mo(O)(O2)2(Mepz)2] in the ionic liquid [C4mim][PF6]. Also, the compounds [HMepz]4[Mo8O26(Mepz)2]·2H2O, 1, [Hdmpz]4[Mo8O26(dmpz)2]·2dmpz, 2, and [Hpz]4[Mo8O22(O2)4(pz)2]·3H2O, 3, were obtained by treating in water, stoichiometrically, dimethylsulfoxide and the corresponding [Mo(O)(O2)2(L)2] complex (L = Mepz; 3,5-dimethylpyrazole, dmpz; pyrazol, pz). The crystal structures of octanuclear compounds 1–3 were indirect proof of the formation of the theoretically proposed intermediates.
Molybdenum-catalysed oxidation of cyclohexene with hydrogen peroxide in the presence of alcohols and X-ray structures of octamolybdate [C(4)mim](4)[Mo8O26] and tetraperoxodimolybdate [Htmpy](2)[{MoO(O-2)(2)}(2)(mu-O)] complexes
(Elsevier, 2013-04) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Álvarez, Eleuterio; Herbert, Matthew; Galindo del Pozo, Agustín; Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
The direct formation of a β-alcoxyalcohol from the corresponding olefin was investigated through the study of the oxidation of cyclohexene with hydrogen peroxide, as test reaction, catalysed by commercially available MoO3 in the presence of alcohols. The formation of the corresponding β-alcoxycyclohexanol was favourable in the order Me > Et > iPr > tBu, reaching approximately no yield for tBuOH. In this reaction, the lack of selectivity was due to the simultaneous formation of cyclohexane-1,2-diol by epoxide hydrolysis, a reaction that it is competitive with respect to the epoxide ring-opening reaction by the alcohol. In order to decrease the cyclohexane-1,2-diol yield, by preventing the hydrolysis reaction, several strategies were analysed and discussed. In particular, 2-methoxycyclohexanol was obtained with high yields and 99% selectivity by using as catalyst the [C4mim]4[Mo8O26] complex (C4mim = 1-butyl-3-methylimidazolium). The structure of the latter octamolybdate and also that of the tetraperoxodimolybdate [Htmpy]2[{MoO(O2)2}2(μ-O)] (tmpy = 2,4,6-trimethylpyridine) complex were determined by X-ray crystallography. The latter complex shows a μ2-oxygen bridging atom and two μ2-κ2–κ1-peroxo bridging ligands. This overall coordination assembly is unprecedented for binuclear molybdenum complexes.
Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis to improve teaching of the chemical and environmental engineering department in master's studies
(Elsevier, 2025) Ronda Gálvez, Alicia; Portillo Estévez, Esmeralda; Gallego Fernández, Luz Marina; Arnáiz Franco, Carmen; Luna Galiano, Yolanda; Rodríguez Galán, Mónica; Fernández Baco, Custodia; Villegas Sánchez, Rosario; Vega Borrero, Fernando; Leiva Fernández, Carlos; Arroyo Torralvo, Fátima; Ingeniería Química y Ambiental
University teaching must be continuously evaluated to identify weaknesses and propose the improvement actions to avoid the lack of motivation by the students and to encouraged them to participate into the learning process. The analysis is not always carried out efficiently due to its complexity. For this reason, this study evaluates the application of a SWOT analysis in the teaching of the Environmental Engineering Master (EEM) and Chemical Engineering Master (CEM) at the University of Seville (US). The SWOT methodology consisted of identifying weaknesses and suggesting ways to improve, which were implemented through various teaching innovation projects. Several weaknesses were identified such as difficulties with the initial adaptation process, high academic workload and poor academic performance. A portfolio of improvement actions was designed and applied in the CEM and EEM. It was observed that the duration of studies decreased 0.85 and 0.13 years for EEM and CEM, respectively and that the number of students presenting their Master's theses in the same year of enrolment increased by 27 %. The main results were the high level of student satisfaction - 4.21/5.00 in the last survey and the significant improvement of key learning aspects such as interdisciplinarity, learning outcomes and student/professor engagement.
Theoretical Prediction of the Electronic Properties of Bidentate Ligands (HEP2) and Synthesis of Bis(N-heterocyclic carbene) Silver and Palladium Complexes
(American Chemical Society (ACS), 2025-07) Carrasco Carrasco, Carlos Jesús; Montilla Ramos, Francisco Javier; Álvarez, Eleuterio; Galindo del Pozo, Agustín; Química Inorgánica; Universidad de Sevilla
A theoretical approach based on density functional theory (DFT) was developed to determine the electronic Huynh parameter for bidentate ligands (HEP2). The 13C chemical shift of the carbene carbon atom in the 1,3-diisopropylbenzimidazolin-2-ylidene ligand (iPr2-bimy) was calculated within the model complexes [PdBr(L2)(iPr2-bimy)]+, where L2 represents a bidentate ligand. Strong correlations were observed between the calculated and experimental chemical shifts for both N-donor and C-donor L2 ligands, with R2 values of 0.9699 and 0.9926, respectively. This DFT approach demonstrates the potential for estimating the HEP2 parameter of bidentate ligands of these types. This method was applied to estimate the HEP2 values for three bis(N-heterocyclic carbene) ligands containing carboxylate groups, (diNHCR)2–, which are explored as ligands in this study. These NHC ligands were derived from three precursor compounds: 1-(carboxymethyl)-3-((3-(carboxymethyl)-1H-imidazol-3-ium-1-yl)methyl)-1H-imidazol-3-ium bromide (1a), 1-(1-carboxyethyl)-3-((3-(1-carboxyethyl)-1H-imidazol-3-ium-1-yl) methyl)-1H-imidazol-3-ium bromide (1b), and 2-(1-(2-(1-(carboxymethyl)-1H-imidazol-3-ium-3-yl)ethyl)-1H-imidazol-3-ium-3-yl)acetate bromide (1c). They were synthesized and characterized using IR, NMR, and single-crystal X-ray crystallography (for 1a and 1c). The interaction of 1a and 1c with Ag2O in the presence of aqueous sodium hydroxide produced the complexes [Na2(H2O)8][Ag2(diCH2NHCH)2] (2a) and [Na2(H2O)8][Ag2(diC2H4NHCH)2] (2c), respectively. Complex 2a was structurally characterized, revealing a binuclear structure in which the bis-carbene ligand adopts a bridging μ-κ1(C),κ1(C′) coordination. Furthermore, 2a exhibited reactivity in transmetalation, allowing the synthesis of complex [Na2(H2O)10][Pd(diCH2NHCH)2] (3a) through a reaction with palladium acetate. Complex 3a, which was also structurally characterized, consists of a mononuclear tetracarbene species where each bis-carbene ligand coordinates in a bidentate κ2(C,C′) fashion.
Dynamic life cycle assessment of climate change impacts of hydrogen production from energy crops
(Elsevier, 2025-11) Romero Piñeiro, Laura; Villanueva Perales, Ángel Luis; Alonso-Fariñas, Bernabé; García Haro, Pedro; Ingeniería Química y Ambiental; European Union (UE); Junta de Andalucía; Ministerio de Ciencia e Innovación (MICIN). España
Life Cycle Assessments (LCAs) are predominantly conducted using a static approach, which aggregates emissions over time without considering emissions timing. Additionally, LCAs often assume biogenic carbon neutrality, neglecting site-specific forest carbon fluxes and temporal trade-offs. This study applies both static and dynamic LCA and incorporates biogenic carbon to evaluate the climate change impact of hydrogen production. It focuses on gasification of eucalyptus woodchips cultivated on former marginal grasslands (BIO system), which avoids competition with land used for food production. A case study is presented in western Andalusia (Spain) with the aim to replace hydrogen produced via the conventional steam methane reforming (SMR) pathway (BAU system) at La Rábida refinery. The CO2FIX model was used to simulate biogenic carbon fluxes, providing insights into carbon sequestration dynamics, and it was found that the inclusion of biogenic carbon flows from eucalyptus plantations dramatically reduced CO₂ equivalent emissions (176 % in the static approach and 369 % in the dynamic approach) primarily due to soil and belowground biomass carbon sequestration. The dynamic LCA showed significantly lower CO₂ emissions than the static LCA (106 % reduction), shifting emissions from −1.79 kg CO₂/kg H₂ in the static approach to −3.69 kg CO₂/kg H₂ in the dynamic approach. These findings highlight the need to integrate emission dynamics and biogenic carbon flows into LCA methodologies to support informed decision-making and the development of more effective environmental policies.
Advances in research project IBUMECO2: project and process description, methodology, and goals expected
(Society of Chemical Industry and John Wiley & Sons Ltd., 2023) Gallego Fernández, Luz Marina; Portillo Estévez, Esmeralda; Baena Moreno, Francisco Manuel; Vilches Arenas, Luis Francisco; Navarrete Rubia, Benito; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; TEP135: Ingeniería Ambiental y de Procesos
In this work, the research project IBUMECO 2 is presented for the first time. This project risesas a need to implement negative emissions technologies and circular economy approaches in ourcurrent energy production system. The overall goal of the project is the integration of CO 2 capture andutilization in biogas upgrading plants in combination with membrane technology for solventregeneration. The integration of CO2 capture and utilization in biogas upgrading plants is pivotal for twomain reasons: (1) it allows to obtain biomethane, a potential substitute of natural gas; (2) the utilizationof the CO2 contained in biogas makes the idea a negative emission technology. The implementation ofmembrane technology for solvent regeneration makes the process affordable and includes it in acircular economy framework. In this paper, the project and the process are deeply described, includingpotential technological improvements identified by a state-of-the-art, the methodology and goalsexpected.
Implementation of a continuous assessment system through the creation of a problem book using DOCTUS in general chemistry subjects
(Elsevier, 2025) Leiva Fernández, Carlos; Arroyo Torralvo, Fátima; Luna Galiano, Yolanda; Ronda Gálvez, Alicia; Muñoz de la Peña Sequedo, David; Ingeniería Química y Ambiental; Ingeniería de Sistemas y Automática
A continuous evaluation system, integrating both formative and summative assessments has been implemented in a Chemistry subject with a high number of students. This system employs a personalized problem notebook developed through an application (DOCTUS), enabling the generation of individualized complex problem statements, easy correction, and multiple submission opportunities. This approach facilitates effective feedback, promotes autonomous and cooperative learning, accelerates the learning process, and enhances activity achievement levels. The experience has been carried out with a group of 91 students enrolled per year in the subject 'Chemistry' corresponding to the first academic year in degree of Chemical Engineering at the Higher Technical School of Engineering (University of Seville), although only 71 have participated in the activity. The platform used, which offers free access, was utilized to create personalized problem notebooks for each student. It assigns identical problems with personalized data and corrects submissions via Excel files in under 10 s. An improvement in the results has been observed; since the students have obtained a numerical grade for their work instantly after delivery of the problem, and they can redo it at a short time (hours), when the students still have the problem in their mind, where they want and with the material that they consider, and without a large increase in the amount of time spent by the teacher. The final qualification was on average 1.2 points higher than previous years. Compared to other subjects in the same academic year, Chemistry had a lower percentage of students who did not participated in the subject (22 % compared to 30–54 % in other subjects from the same course). The number of approved students has increased, reflected in the number of repeaters, which decreased in the next year from 42 % to 29 %.
Evaluation of Spent Catalyst from Fluid Catalytic Cracking in Fly Ash and Blast Furnace Slag Based Alkali Activated Materials
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Luna Galiano, Yolanda; Cabrera Gallardo, Domingo; Rodríguez Galán, Mónica; Novais, Rui M.; Labrincha, J.A.; Leiva Fernández, Carlos; Ingeniería Química y Ambiental
The objective of this work is to evaluate how spent catalyst from fluid catalytic cracking (SCFCC) affects the physical, mechanical and durability properties of fly ash (FA) and blast furnace slag (BFS)-based alkali-activated materials (AAMs). Recycling of SCFCC by integrating it in a AAM matrix offers several advantages: valorization of the material, reducing its disposal in landfills and the landfill cost, and minimizing the environmental impact. Mineralogical, physical and mechanical characterization were carried out. The durability of the specimens was studied by performing acid attack and thermal stability tests. Mass variation, compressive strength and porosity parameters were determined to assess the durability. BFS- and FA-based AAMs have a different chemical composition, which contribute to variations in microstructure and physical and mechanical properties. Acid neutralization capacity was also determined to analyse the acid attack results. Porosity, including the pore size distribution, and the acid neutralization capacity are crucial in explaining the resistance of the AAMs to sulfuric acid attack and thermal degradation. Herein, a novel route was explored, the use of SCFCC to enhance the durability of AAMs under harsh operating conditions since results show that the compositions containing SCFCC showed lower strength decay due to the lower macroporosity proportions in these compositions.
Anaerobic Digestion as an Alternative to Improve the Industrial Production of MnP Economically and Environmentally Using Olive Mill Solid Waste as the Substrate
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Araneda, Michael; Pinto Ibieta, Fernanda; Alonso-Fariñas, Bernabé; Fermoso, Fernando G.; Ciudad, Gustavo; Ingeniería Química y Ambiental; Agencia Nacional de Investigación y Desarrollo (ANID). Chile
Manganese peroxidase (MnP) is widely studied for its potential in bioremediation, although its production typically relies on costly synthetic culture media (SCM). This study evaluates olive mill solid waste (OMSW) as a sustainable substrate for MnP production. Three alternatives were evaluated: (1) using SCM; (2) using OMSW; and (3) using OMSW, followed by anaerobic digestion (AD). The alternatives were evaluated by both an economic and life cycle assessment (LCA). The economic analysis considered indicators such as net present value (NPV), internal rate of return (IRR), and payback period. The LCA methodology was conducted according to ISO 14040/44 standards, with a cradle-to-gate system boundary, using SimaPro v9.4 software. Replacing SCM with OMSW improved economic performance, though environmental impacts showed no significant improvement and, in some cases, worsened. In contrast, combining OMSW with anaerobic digestion enhanced both dimensions: Alternative 3 reached the highest NPV (USD 984,464), a 20.9% IRR, and a 4.1-year payback, while reducing impacts by 275% (Stratospheric ozone depletion), 89% (terrestrial ecotoxicity), 78% (freshwater ecotoxicity), and 50% (marine eutrophication) compared to Alternative 1. Finally, the use of OMSW combined with AD reduces economic costs and environmental impact, contributing to the field of sustainable enzyme production.
Numerical and experimental study of the optimal specimen geometry for direct tension strength tests in high tensile strength fiber reinforced concrete
(Nature Research, 2025-03-28) Vicente Cabrera, Miguel Ángel; Mena Alonso, Álvaro; González Cabrera, Dorys Carmen; Ruiz López, Gonzalo; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Yu, Rena C.; Mínguez Algarra, Jesús; Mecánica de Medios Continuos y Teoría de Estructuras; Ingeniería Química y Ambiental; Ministerio de Economía y Competitividad (MINECO). España; TEP972: Mecánica de Materiales y Estructuras; TEP142: Ingeniería de Residuos
The accurate determination of the tensile strength of concrete is a topic of growing interest, especially driven by the new ultra-high tensile strength fiber-reinforced concretes. However, this is a complex task, as traditional methods provide inconsistent results (both splitting tensile test and 3-point bending test). The most robust method is the direct tensile test. However, in concrete, it poses a technical challenge that has not yet been satisfactorily solved. The aim of this study is the design of a test specimen that maximizes the percentage of successful failure and also allows a viable anchorage solution to the load application equipment, especially for high and ultra-high tensile strength concretes. An optimized geometry of a bone-shaped specimen that maximizes the probability of collapse occurring at the central neck is presented. First, a mathematical function of the generatrix of the bone-shape specimen is presented. The behavior of the solution is also analyzed numerically and statistically, comparing it with other commonly used solutions for direct tensile tests. Additionally, the design, fabrication, and calibration of a tailored cardan joint for load centering, thus minimizing its eccentricity and the dispersion of the results. Finally, the results of a static test campaign carried out on six carbon-fiber reinforced high tensile strength concrete specimens. The proposed bone-shaped specimen shows a much higher percentage of successful failures than the other specimen geometries commonly used for tensile testing, which improves the quality of tensile characterization test campaigns for high and ultra-high tensile strength concretes.

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