Artículos (Ingeniería Química y Ambiental)

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

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Water‑specific toxicity factor and index for heavy metal risk assessment: application to urban lakes in Chennai, India
(Springer Nature, 2026) Rosado Alcarria, Daniel; Nambi, Indumathi; Fohrer, Nicola; Ingeniería Química y Ambiental; Deutsche Hydrologische Gesellschaft (DHG). Alemania; German Academic Exchange Service (DAAD). Alemania; Indo German Centre for Sustainability (IGCS). India
Heavy metals released into aquatic environments disrupt ecological balance. Urban lakes in the Pallikaranai catchment, Chennai, India, face pollution pressures from rapid urbanization. This study introduces a water-specific toxicity factor and toxicity index to assess toxicity risks posed by heavy metals in surface waters to aquatic life. Results revealed considerable variability in in situ water quality parameters, including pH, electrical conductivity, and dissolved oxygen. pH was mostly neutral to alkaline, with some lakes experiencing anoxia while others exceeded 10 mg/L oxygen. Pb and Cu posed the highest toxicity risks in water, with several samples reaching Class II and III in the United Nations Economic Commission for Europe (UNECE) classification, indicating potential toxicity risks. In sediments, Cr and Ni posed the highest toxicity risks, exceeding the PEC in all samples and Cu and Zn frequently exceeding sediment quality thresholds. Exceeding the TEC indicates possible toxic effects, while surpassing the PEC suggests probable toxic effects to aquatic biota. Compared to other polluted urban water bodies globally, the Pallikaranai catchment exhibited relatively low water contamination and high sediment contamination, particularly for Cr, Cu, Ni, and Zn. The newly developed water toxicity index, based on UNECE guidelines, indicated varying levels of potential ecological risk across lakes. This study highlights the need for monitoring and effective pollution mitigation strategies to protect the aquatic ecosystems of the Pallikaranai catchment. The proposed toxicity index provides a practical screening tool for assessing and prioritizing heavy metal risks in urban aquatic environments.
Autoclave curing of nanosilica-modified ultra-high-performance concrete matrix: microstructural development, mechanical performance and fracture behaviour
(Elsevier, 2026-09) Ruiz Martínez, Jaime D.; Ríos Jiménez, José David; Carrasco Carrasco, Carlos Jesús; Luna Galiano, Yolanda; Cifuentes-Bulté, Héctor; Leiva Fernández, Carlos; Ingeniería Química y Ambiental; Mecánica de Medios Continuos y Teoría de Estructuras; Ministerio de Ciencia, Innovación y Universidades (MICIU). España
This study investigates the combined effect of nanosilica incorporation and autoclave curing on the hydration behaviour, microstructural development, and mechanical performance of ultra-high-performance concrete. The investigated material corresponds to a non-fibre UHPC matrix specifically designed for subsequent fibre reinforcement applications. Mixtures containing 0–7.5 wt% NS were subjected to standard curing and autoclave curing, and were characterised by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and mercury intrusion porosimetry. XRD results show that nanosilica addition under standard curing increases the amorphous content due to accelerated clinker hydration and enhanced pozzolanic activity. In contrast, autoclave curing promotes the transformation of amorphous or weakly crystalline calcium silicate hydrate into thermodynamically stable and highly ordered tobermorite. Under autoclave curing conditions, nanosilica provides a highly reactive source of SiO₂, facilitating portlandite consumption and the crystallization of stable calcium silicate hydrates. Scanning Electron Microscopy observations corroborate these findings, revealing a transition from dense but disordered gel-like hydration products in standard curing mixtures to well-defined crystalline morphologies in autoclave treated specimens. TGA results further support the mineralogical trends identified by XRD, with nanosilica and autoclave modified mixtures exhibiting reduced mass losses associated with portlandite dihydroxylation. Porosimetry analysis indicates that moderate nanosilica dosages refine the pore structure. Overall, the synergistic use of nanosilica (3.5 wt%) and autoclave results in a refined and stabilized microstructure, which explains the observed improvement in the mechanical performance (average increases of 16% in compressive strength and 51% in tensile strength) of ultra high-performance concrete. Therefore, the reported fracture properties correspond to the matrix behaviour and do not include fibre-bridging effects typically observed in fibre-reinforced UHPC systems.
Steam gasification reactivity of potassium-doped wood chars in a fluidized bed
(American Chemical Society, 2025-10) González, William A.; Nilsson, Susanna Louise; Fuentes Cano, Diego Javier; Ronda Gálvez, Alicia; Gómez Barea, Alberto; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España
The steam gasification reactivity of potassium-doped wood chars was evaluated in a fluidized bed (FB) reactor at atmospheric pressure. The experimental conditions were selected aiming at studying the char conversion kinetics during the sorption enhanced gasification (SEG) process (systems characterized by relatively low operating temperature due to the equilibrium constraint of calcium oxide (CaO) carbonation). Therefore, the temperature range studied is between 650 and 900 °C, with special emphasis on the lower range of temperature. The fluidizing gas compositions studied presented high H2O partial pressures between 0.30 and 0.50 bar and H2 partial pressures in the range of 0–0.20 bar to assess the H2 inhibition effect. Both nth-order and Langmuir–Hinshelwood (L-H) kinetic expressions were obtained to describe the reaction rate as a function of the temperature and partial pressure of gas species. The Modified Random Pore Model (MRPM) represents well the evolution of the reaction rate with the degree of carbon conversion. The H2 inhibition effect was especially significant under the conditions of high reaction rates (high temperatures and potassium-doped char). The addition of potassium significantly increases the char gasification rate, yielding values 3–5.5 times higher than those of untreated char and allowing significant char gasification rates to be achieved at temperatures as low as 650 °C.
Calcination of Ca-Based Sorbents in the Presence of Steam for Sorption-Enhanced Gasification Applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2026-05) González, William A.; Nilsson, Susanna Louise; Fuentes Cano, Diego Javier; Ronda Gálvez, Alicia; Gómez Barea, Alberto; Ingeniería Química y Ambiental; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España
The calcination kinetics of limestone and dolomite under conditions relevant to sorption-enhanced gasification (SEG) were investigated: mild temperature (775–850 °C), low CO2 partial pressure (0.05–0.10 bar), and a steam-rich (H2O balance) atmosphere. Experiments with two Ca-based sorbents (limestone and dolomite) were conducted in a fluidized bed reactor to assess both initial calcination kinetics and multicycle deactivation during 10 cycles under SEG carbonation conditions at 650 °C. Dolomite exhibited markedly higher calcination rates than limestone, which is consistent with the structural modifications induced by MgCO3 decomposition and the presence of MgO, resulting in a slightly lower apparent activation energy (115.96 kJ mol−1 for dolomite compared to 120.27 kJ mol−1 for limestone). Both sorbents showed a strong sensitivity to the deviation from the equilibrium CO2 partial pressure, with reaction orders near 2. The presence of steam was confirmed to have a significant catalytic effect, accelerating the first-cycle calcination rate compared to dry N2 conditions. Sorbent deactivation caused by sintering was more pronounced at higher temperatures and CO2 pressures. Dolomite showed significantly less deactivation, compared to limestone, which can be attributed to the increase in structural stability due to the presence of MgO. The kinetics obtained in this work contribute to the design of stable SEG based on dual fluidized bed reactors, particularly to assist in the selection of calcination operating conditions to minimize sorbent deactivation and in the development of stable CO2-sorbents.
A Narrative Review of Dimethyl Ether Production Technologies with a Focus on Landfill Biogas Potential as Feedstock
(Multidisciplinary Digital Publishing Institute (MDPI), 2026-05) Cabrera-Gallardo, Domingo; Quintero-Quintana, María Camila; Baena-Moreno, Francisco M.; Rodríguez Galán, Mónica; Vidal Barrero, Fernando; Ingeniería Química y Ambiental
Following the rising global demand for sustainable solutions within the chemical industry, this narrative review evaluates dimethyl ether (DME) production routes focusing on both economic performance and environmental sustainability. Special focus is given to landfill biogas (LFB) as a source to obtain DME. Assessment was performed through narrative comparison of facility capacity, DME pricing, environmental impacts, and Technology Readiness Level (TRL). Studies from 2015 onwards are considered, unless well-established methods are referenced. We searched for industrial-scale studies reporting economic viability and techno-economic-environmental feasibility, including modeling plants, government reports, and conference papers in English. Two primary routes for DME synthesis are identified: the commercially proven indirect route, and an emerging, future-focused direct synthesis in a single reactor. A comparative analysis reveals that natural gas (NG) and coal are the most economical feedstocks for DME synthesis (305–485 €/t), but carry the highest environmental impacts. Biogenic feedstocks offer economic competitiveness (270–550 €/t for biomass and 350–785 €/t for biogas) with lower CO2 emissions, while renewable hydrogen and carbon capture CO2 are recognized as long-term solutions (910–2610 €/t). The timeline for their industrial realization will be determined by advancements in innovation, research, and economic incentives to bridge the price gaps existing today.
MRI investigation of swelling of super absorbent polymer: effects of particle size
(Springer, 2026) Tiernan, Hannah; Salestan, Saeed Khoshhal; Baena-Moreno, Francisco M.; Moghadasi, Ramin; Karlson, Tomas; Hanson, Charlotta; Bernin, Diana; Ingeniería Química y Ambiental
Superabsorbent polymers (SAP) are crucial components of hygiene products. Their method of manufacture, particle size, and the presence of ions enable the performance of SAP to be tailored towards different applications. The efficacy of their function could be attributed to the distribution of H2O molecules within the sample, e.g. transporting the liquid away from the skin. We therefore aim to further elucidate this process using magnetic resonance imaging (MRI). Here we utiliszed MRI techniques, relaxation times, diffusion coefficient measurements and 1D profiling, to investigate the distribution of H2O molecules in SAPs while varying particle size and the presence of NaCl in the solution to be absorbed. Through detailed analysis of the MRI results, factors such as the pushed height of the plunger, spatial swelling heterogeneity, and the swelling of the SAP particles could be monitored. As expected, SAP particles swelled less in saline solution. The H2O absorption appeared the most homogenous for the smallest particle size. It shows, in a comparable manner, the position of water and its state in terms of being free or strongly associated. The analytical measures and representative maps of fluid distribution were proved to shed light on fluids absorption in a bed of gelling particles. The results suggest that a homogeneous swelling and a faster H2O absorption might occur with smaller SAP particles. These findings provide valuable insights into fluid transport and mechanical response in SAPs, which are critical for optimising their application in hygiene products.
Bioremediation of Contaminated Soils with Hydrocarbons Using Industrial Wastewater Treatment Plant Effluents in a Circular Economy Model
(American Chemical Society (ACS), 2026-05) Ritoré, Emilio; Morillo Aguado, José; Arnáiz Franco, Carmen; Egea-Corbacho, Ágata; Usero García, José; Ingeniería Química y Ambiental
Soil contamination by hydrocarbons poses a persistent threat to terrestrial and aquatic ecosystems, affecting soil quality, biodiversity, and human health. Given the limitations of traditional physical–chemical techniques, bioremediation has emerged as a sustainable alternative based on microbial activity to degrade toxic compounds. This study evaluated the suitability of secondary clarifier effluent and activated sludge from refinery and chemical industry wastewater treatment plants (WWTPs) for the bioremediation of petroleum-contaminated soils, with and without the addition of NPK (Nitrogen, Phosphorus, and Potassium) nutrients. This approach aligns with circular economy principles by promoting the reuse of industrial byproducts as biostimulants and supports the objectives of the Sustainable Development Goals. Microcosm tests were conducted over 20 weeks, assessing hydrocarbon degradation by chromatography and catalase activity as an enzymatic indicator. All treatments enhanced biodegradation compared to the control, achieving 65–79% total hydrocarbon removal. Activated sludge from La Rábida refinery with NPK (AS-RF + NPK) was the most effective, showing degradation from the first weeks. Light hydrocarbons (C6–C8) were almost completely removed, whereas long-chain compounds (C21–C35) were more resistant. Aromatic hydrocarbons, including benzene, toluene, ethylbenzene, and xylenes (BTEX), reached 100% removal in all treatments, demonstrating the strong biodegradation potential of microorganisms present in industrial effluents.
Multi-Component 3D bioprinted platform with sacrificial matrix and collagen-based bioinks for skeletal muscle tissue engineering
(MDPI, 2026-05-17) Granados Carrera, Carmen M.; Calero Castro, Francisco José; Pérez-Puyana, Víctor Manuel; Jiménez-Rosado, Mercedes; Navarrete-Damián, Jaime; Portilla de Juan, Fernando de la; Romero García, Alberto; Cirugía; Ingeniería Química y Ambiental; Ingeniería y Ciencia de los Materiales y del Transporte; Ingeniería Química; MICIU/AEI/10.13039/501100011033/ERDF/EU; TEP229: Tecnología y Diseño de Productos Multicomponentes
The development of biomimetic and mechanically functional constructs remains a major challenge in skeletal muscle tissue engineering. In this study, we present a multi-component 3D bioprinted platform integrating a polycaprolactone (PCL) support for mechanical stimulation, a sacrificial gelatin (GE) matrix for controlled bioink deposition, and collagen-based bioinks laden with Rattus norvegicus L6 skeletal muscle cells. The influence of PCL architecture, GE concentration (0.75, 1.5 and 3 wt%), and bioink composition—collagen (C), collagen–Matrigel (CM), and extracellular matrix-based (ECM)—was systematically evaluated. Rheological characterization demonstrated that all bioinks exhibited shear-thinning behavior and suitable viscoelastic properties for extrusion-based bioprinting, with sufficient mechanical stability to withstand dynamic bioreactor conditions. Microstructural analysis revealed highly interconnected porous networks, particularly in ECM-based scaffolds. While no statistically significant differences were observed, the ECM-based bioinks showed the highest cell viability and improved structural organization. Overall, this work demonstrates a versatile bioprinting strategy that combines mechanical support and biomimetic environments, highlighting the potential of ECM-based bioinks for the fabrication of functional skeletal muscle constructs.
Influence of plasticizers on the properties of soy-based bioplastic matrices for controlled release of iron
(Elsevier, 2026) Castro Criado, Daniel; Jiménez Rosado, Mercedes; Granados Carrera, Carmen M.; Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Ingeniería Química; Ingeniería Química y Ambiental; Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Union (UE); Ministerio de Hacienda y Función Pública; Junta de Andalucía; Consejería de Universidad, Investigación e Innovación
The global increase in horticultural production, driven by population growth and the resulting high food demand, has promoted the adoption of intensive cultivation systems that require large amounts of fertilizer. However, the low efficiency of conventional practices and their environmental impacts have driven the development of alternative strategies, such as controlled-release fertilizers. Soy protein isolate (SPI) bioplastics were developed, and the influence of plasticizers on their properties was analyzed. Bioplastic matrices were processed by compression molding at 300 bar using this by-product combined with different concentrations of water and glycerol (5, 10, and 15 wt%) as plasticizers and 5 wt% of iron sulphate heptahydrate as a micronutrient. Thus, physicochemical, mechanical, morphological and functional properties were assessed. Moreover, crop analyses were conducted to assess the potential biofortification effects of these systems. The results show that both plasticizers led to systems with similar elastic modulus (6.22 and 6.03 for systems 10/0 and 0/10, respectively). When glycerol is used, the systems exhibit greater instability than water-plasticized systems, as reflected by steeper slopes of the elastic moduli (70 and 120 for systems 10/0 and 0/10, respectively). Overall, these products demonstrated high potential for horticultural applications. They enabled optimal micronutrient assimilation by plants, which is reflected in increased biomass and crop weight, showing values from 33.3 to 41.5 g, matching or exceeding the positive control values (30.8 ± 5.3 g), while positively contributing to the soil, by-product valorization and nutrient delivery to soils within a circular-economy context.
Testing the ability to reduce the leaching of pesticides in soil amended with agro-industrial and composted waste
(Elsevier, 2026) Rojas, Raquel; Morillo Aguado, José; Usero García, José; Álvarez Herrera, Consuelo; Repetto, Guillermo; Ingeniería Química y Ambiental; Junta de Andalucía; Universidad Pablo de Olavide
The retention potential of composted sewage sludge, orujillo (a solid residue from olive oil production), sawdust and sunflower seed shell to prevent soil leaching of atrazine, chlorfenvinphos, and chlorpyrifos was studied in open systems using fixed-bed adsorption columns. The columns were constructed from soil and the soil was amended with 10% of the organic waste cited. Pesticides were applied, and columns were subjected to simulated rainfall. Breakthrough and cumulative curves were built from pesticides detected each day in leachates, as % of applied. Our analysis reveals that the effectiveness of these amendments is not universal; it depends critically on the molecular structure of the pesticides and how it interacts with the physicochemical properties of the amendments and the soil. Orujillo emerged as the most broadly effective amendment, reducing elution peaks by up to 7.6-fold for chlorfenvinphos and significantly delaying atrazine breakthrough via lignin partitioning. Exploratory multiparametric and LASSO regression analyses identified oxygen content (%) and calcium (%) as the most influential properties controlling distribution coefficients and cumulative leaching. Furthermore, we found that amended soils require significantly greater irrigation volumes to reach equilibrium, providing a “resilience factor” against extreme rainfall events. Discrepancies between batch and column results highlight that laboratory-derived constants often fail to predict leaching under dynamic flow conditions.
Key emerging contaminants and their implications for water quality: A critical review of occurrence, regulation, and treatment performance
(Elsevier, 2026-06) Rodríguez, Rocío; Arteaga-Naranjo, Miguel Oswaldo; Arellano, Juana María; Albendín, María Gemma; Coello, Dolores; Egea-Corbacho, Ágata; Ingeniería Química y Ambiental; European Union (UE); Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla
Emerging contaminants (ECs) have gained increasing scientific and societal attention in recent decades due to their environmental persistence, potential toxicity, and limited regulatory control. This review synthesizes current knowledge on their occurrence in aquatic systems, the evolving legislative framework, and the effectiveness of available removal technologies. Unlike previous papers that typically isolate specific pollutant classes, the novelty of this review lies in providing a unified framework that simultaneously integrates the environmental occurrence, regulatory evolution, and treatment performance of seven representative substances (diclofenac, azithromycin, 17β-estradiol, bisphenol-A, glyphosate, imidacloprid, and thiamethoxam). Analysis of 92 scientific publications and regulatory documents revealed a marked rise in research activity between 2012 and 2025 confirming alarming concentrations across aquatic systems. A critical challenge identified is the widespread absence of binding concentration limits despite recent legislative progress (e.g., Directive (EU) 2024/3019), which severely hinders effective risk management. Another major challenge is the persistent failure of conventional wastewater treatments, coupled with significant knowledge gaps regarding full-scale removal of specific compounds like glyphosate. Spain's Royal Decree 1085/2024 requires monitoring of emerging contaminants in reclaimed water, but it does not establish binding concentration limits for many substances. High levels of these contaminants have been reported in surface water, wastewater, and groundwater. Twenty‑two removal technologies were identified, with multibarrier systems, ozonation combined with activated carbon, membrane bioreactors, and biochar adsorption achieving the highest efficiencies (typically >80%, and in some cases >90%). Conversely, conventional treatments such as activated sludge showed limited performance, and a significant knowledge gap regarding glyphosate removal under full-scale conditions and standardized monitoring frameworks. Ultimately, this review concludes that mitigating the threat of ECs will require the progressive adoption of quaternary treatments, supported by the development of harmonized and legally binding environmental thresholds.
Continuous supercritical water gasification of orange peel, sewage sludge, and dairy waste model compounds
(Elsevier, 2026-03) López-Guirao, Francisco; Gutiérrez Ortiz, Francisco Javier; Ingeniería Química y Ambiental; Junta de Andalucía
An experimental study of the supercritical water gasification (SCWG) of six model compounds (glucose, fructose, xylose, phenol, lactose, and glycine) was carried out individually and in different mixtures in a continuous tubular reactor without using a catalyst to produce hydrogen. Experiments were conducted at 240 bar, temperatures of 600 °C, 700 °C, and 800 °C, and feed concentrations of 5 or 7.5 wt% using a flow rate of 1 L/h. The dry gas produced primarily consisted of H2, CO2, CH4, and CO. The effects of key operating parameters, such as temperature, organic feed concentration, on gas composition and yields were experimentally studied and compared with thermodynamic equilibrium calculations performed by AspenPlus™, using the PSRK equation of state. The experimental results provide new insights, especially for diverse mixtures of model compounds representing high-moisture waste, such as orange peel, sewage sludge, and dairy waste. While numerous SCWG studies focus on individual model compounds, experimental research on multicomponent mixtures in continuous reactors remains extremely limited, particularly with respect to interaction effects among chemically diverse species. Real biomass and waste streams consist of interacting carbohydrates, phenolics, and nitrogen-containing compounds whose combined behavior cannot be inferred from single-compound experiments. This study fills that gap by experimentally demonstrating non-additive behavior and interaction effects in SCWG of representative mixtures, supported by integrated gas- and liquid-phase analysis and mechanistic interpretation consistent with hydrothermal chemistry.
A review on high-pressure heterogeneous catalytic processes for gas-phase CO2 valorization
(Elsevier, 2024-01-01) Villora Picó, Juan J.; González Arias, Judith; Pastor Pérez, Laura; Odriozola Gordón, José Antonio; Ramírez Reina, Tomás; Química Inorgánica; Ingeniería Química y Ambiental; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Junta de Andalucía
This review discusses the importance of mitigating CO2 emissions by valorizing CO2 through high-pressure catalytic processes. It focuses on various key processes, including CO2 methanation, reverse water-gas shift, methane dry reforming, methanol, and dimethyl ether synthesis, emphasizing pros and cons of high-pressure operation. CO2 methanation, methanol synthesis, and dimethyl ether synthesis reactions are thermodynamically favored under high- pressure conditions. However, in the case of methane dry reforming and reverse water-gas shift, applying high pressure, results in decreased selectivity toward desired products and an increase in coke production, which can be detrimental to both the catalyst and the reaction system. Nevertheless, high-pressure utilization proves industrially advantageous for cost reduction when these processes are integrated with Fischer-Tropsch or methanol synthesis units. This review also compiles recent advances in heterogeneous catalysts design for high-pressure applications. By examining the impact of pressure on CO2 valorization and the state of the art, this work contributes to improving scientific understanding and optimizing these processes for sustainable CO2 management, as well as addressing challenges in high-pressure CO2 valorization that are crucial for industrial scaling-up. This includes the development of cost-effective and robust reactor materials and the development of low-cost catalysts that yield improved selectivity and long-term stability under realistic working environments.
A review of recent advances on the path towards a greener methanol industry
(Elsevier, 2026) Cabrera-Gallardo, Domingo; Baena-Moreno, Francisco M.; Rodríguez Galán, Mónica; Vidal Barrero, Fernando; Ingeniería Química y Ambiental; Centro para el Desarrollo Tecnológico y la Innovación (CDTI). España; TEP135: Ingeniería Ambiental y de Procesos
Methanol, traditionally synthesized through natural gas and coal gasification, is studied as a versatile energy carrier with applications in transport and industrial sectors. Green methanol production has already been acknowledged to play a pivotal role in future energy systems. Furthermore, it offers an alternative to hydrogen-centered energy strategies. However, renewable routes face economic challenges, including high electrolysis costs, energy-intensive CO2 capture, and overall system inefficiencies. This review comprehensively examines the methanol production routes, detailing plant configurations, recent technological advancements, optimal operating conditions, techno-economic analysis and life cycle assessments. We found that methanol selling prize is approximately 100-300 €/t for fossil methanol, 350-1050 €/t for biomethanol, and 500-950 €/t for e-methanol. This significant cost gap is because carbon emissions are not currently reflected in market prices. Regarding environmental analysis, methanol from green and renewable sources has less impacts considering cradle-to-gate emissions than fossil methanol. Overall, the study provides actionable insights to advance green methanol viability in a decarbonized economy.
Chitosan-alginate hybrid hydrogels: Prospects for sustainable horticulture
(Elsevier, 2026-06) Granados Carrera, Carmen M.; Pérez-Puyana, Víctor Manuel; Castro Criado, Daniel; Romero García, Alberto; Ingeniería Química y Ambiental; Ingeniería y Ciencia de los Materiales y del Transporte; Ingeniería Química; TEP229: Tecnología y Diseño de Productos Multicomponentes
New materials are needed to mitigate the eutrophication and soil degradation promoted by fertilizer overuse, highlighting biopolymer-based hydrogels due to their contribution to sustainable agriculture. In this regard, two notable biopolymers emerge: chitosan (CH) and sodium alginate (ALG). Chitosan possesses excellent mechanical properties and has been explored for controlled-release applications, while sodium alginate is known for its water-retention capacity, a critical factor in addressing drought under intensifying climate change. Thus, the objective of this article is the synthesis of hybrid hydrogels combining both biopolymers and characterizing their physicochemical, thermal, mechanical, morphological and functional properties. In this context, 3 distinct formulations were engineered, varying the polymer ratios (100–0, 50–50 and 0–100 CH-ALG). Hence, the synthesis process showed that gelation was enhanced in the case of chitosan due to ionic reinforcement promoted by calcium ions (an increase of 572% in the elastic modulus). The results indicate the formation of hard, stable gels with tan(δ) values below 0.2 and elastic moduli above 10 MPa in some formulations, in combination with thermal stability up to 40 °C (an extreme soil temperature). However, clear trends can be observed: the 50–50 CH-ALG hydrogels exhibited adequate water retention for horticultural applications (4000–6000%, depending on immersion time), highlighting enhanced water absorption compared to commercial formulations that incorporate gelatin. These findings underscore the potential of biopolymer-based hydrogels as a sustainable alternative to traditional fertilizers as well as a vital tool in restoring ecological balance and ensuring food sustainability.
Water-soluble silver nanoparticles stabilized by amino acid-derived N-heterocyclic carbenes: synthesis, properties and theoretical study of the nucleation process
(Royal Socciety of Chemistry, 2026-03) Carrasco Carrasco, Carlos Jesús; Ayala Espinar, Regla; Garrido, Sara; Montilla Ramos, Francisco Javier; Galindo del Pozo, Agustín; Química Inorgánica; Ingeniería Química y Ambiental; Universidad de Sevilla
Silver nanoparticles stabilized by amino acid-derived N-heterocyclic carbenes, denoted as Ag(NHCR)-NPs (R = H, 3a; Me, 3b; iPr, 3c; and iBu, 3d), were synthesized by reducing the parent complexes Na3[Ag (NHCR)2] (2a–d) with NaBH4 under appropriate reaction conditions. The stability of the aqueous AgNP solutions was found to depend strongly on the presence of the NHC ligand, the solution concentration, and the nature of the R substituent. In particular, the stability of the nanoparticles decreases as the steric bulk of R increases. Among the series, 3a (R = H) exhibits remarkable stability in water and can be isolated by ultracentrifugation and lyophilization. Notably, solid Ag(NHCH)-NPs (3a) can be redissolved in water to regenerate a stable AgNP solution. The Ag(NHCR)-NPs were characterized by infrared (IR) and ultraviolet-visible (UV-Vis) spectroscopies, polarimetry, dynamic light scattering (DLS), and transmission electron microscopy (TEM). 3a behaves as an active and versatile nanocatalyst in water, efficiently promoting both the model reduction of 4-nitrophenol to 4-aminophenol and the catalytic hydrolysis of NaBH4 to generate H2 under basic conditions. From a theoretical perspective, the nucleation and growth of the Ag(NHCR)-NPs were modelled using density functional theory (DFT) at the PBE-D3/def2-TZVP level, considering systems of the type [Agn(NHCR)]2− (with R=H,MeandiPrand n=2, 3, 4, 20, 30). The Quantum Theoryof Atoms in Molecules (QTAIM) was employed to analyze the bonding characteristics within the nanoparticles, with particular attention to the Ag–Ag and Ag–C(carbene) interactions. It is noteworthy that the bond dissociation energy (BDE) of the Ag–C(carbene) bond decreases with increasing steric bulk of R, consistent with the experimental observations. Based on experimental data, the Ag:NHC ratio is approximately 30:1 and the calculated IR spectrum of [Ag30(NHCH)]2− model (corresponding to 3a) provides a satisfactory match with the experimental spectrum.
Optimizing biogas methanation over nickel supported on ceria-alumina catalyst: Towards CO
(Elsevier, 2024) González Arias, Judith; Torres Sempere, Guillermo; Arroyo Torralvo, Fátima; Ramírez Reina, Tomás; Odriozola Gordón, José Antonio; Ingeniería Química y Ambiental; Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España
Biogas methanation emerges as a prominent technology for converting biogas into biomethane in a single step. Furthermore, this technology can be implemented at biogas plant locations, supporting local economies and reducing dependence on large energy producers. However, there is a lack of comprehensive studies on biogas methanation, particularly regarding the technical optimization of operational parameters and the profitability analysis of the overall process. To address this gap, our study represents a seminal work on the technical optimization of biogas methanation obtaining an empirical model to predict the performance of biogas methanation. We investigate the influence of operational parameters, such as reaction temperature, H2/CO2 ratio, space velocity, and CO2 share in the biogas stream through an experimental design. Based on previous research we selected a nickel supported on ceria-alumina catalyst; being nickel a benchmark system for methanation process such selection permits a reliable data extrapolation to commercial units. We showcase the remarkable impact of studied key operation parameters, being the temperature, the most critical factor affecting the reaction performance (ca. 2 to 5 times higher than the second most influencing parameter). The impact of the H2/CO2 ratio is also noticeable. The response surfaces and contour maps suggest that a temperature between 350 and 450 °C and an H2/CO2 ratio between 2.5 and 3.2 optimize the reaction performance. Further experimental tests were performed for model validation and optimization leading to a reliable predictive model. Overall, this study provides validated equations for technology scaling-up and techno-economic analysis, thus representing a step ahead towards real-world applications for bio-methane production.
A profitability study for catalytic ammonia production from renewable landfill biogas: Charting a route for the next generation of green ammonia
(Elsevier, 2024) González Arias, Judith; Nawaz, Muhammad Asif; Vidal Barrero, Fernando; Ramírez Reina, Tomás; Ingeniería Química y Ambiental; Química Inorgánica; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España
This study introduces a novel techno-economic approach to renewable ammonia production using landfill biogas. The proposed process involves bio-hydrogen generation from landfill biogas, nitrogen production via air separation, and the Haber-Bosch process. Building on our prior research, which demonstrated the economic competitiveness of renewable hydrogen production from landfill gas, we extend our investigation to analyze the feasibility of producing renewable ammonia from biogas-derived bio-hydrogen. However, the economic analysis for the baseline scenario reveals the current lack of profitability (net present value of −18.3 M€), with ammonia prices needing to quadruple to achieve profitability. Major costs, including investment, maintenance, overhead expenses, and electricity, collectively account for over 70%, suggesting the potential efficacy of investment subsidies as a political tool. Only cases with subsidies exceeding 50% of total investment costs, under current ammonia market prices, would render the green ammonia route profitable. Our findings underscore the significant techno-economic challenges in realizing renewable ammonia production, emphasizing the need for innovation in process engineering and catalytic technologies to enable competitive and scalable green ammonia production.
From alternative protein to functional emulsifier: Ultrasound-engineered emulsions and emulgels stabilized by cricket protein for pumpkin seed oil delivery
(Elsevier, 2026-07) Sánchez-García, Rosa M.; Rodríguez Luna, Azahara María; Santos García, Jenifer; Trujillo-Cayado, Luis Alfonso; Ingeniería Química; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; TEP943: Reología Aplicada. Tecnología de Coloides
Global demand for sustainable, nutrient-dense foods is accelerating the search for alternative proteins with techno-functional value. Here, we developed oil-in-water submicron emulsions using cricket flour protein (Acheta domesticus) as a natural emulsifier and pumpkin seed oil as the lipid phase, and optimized ultrasonic emulsification conditions using response surface methodology. The smallest droplets within the tested domain were obtained at high energy input, 90% amplitude, 20 minutues sonication and 7:3 pulse, reaching submicron sizes (d₃,₂ ≈ 0.55 μm) but with increased polydispersity, consistent with a breakup–recoalescence competition under emulsifier-limited interfacial coverage. To enhance long-term physical stability through continuous-phase structuring and to convert the emulsions into viscoelastic emulgels, advanced performance xanthan gum (APXG) and diutan gum (DG) were added (0.125–0.5 wt%). Both gums induced strong shear-thinning behaviour and increased viscoelasticity; DG generated higher zero-shear viscosity and a more elastic network, whereas APXG provided superior resistance to destabilization during storage as quantified by Turbiscan Stability Index (TSI), achieving minimal changes of TSI at 0.5 wt%, reaching values as low as 2.36 after 60 days at room temperature. These results demonstrate a scalable ultrasound-based route to formulate sustainable submicron emulsions from insect-derived protein and plant oil, and highlight how tailored continuous-phase structuring can decouple texture enhancement from long-term colloidal stability.
A Novel Toxicity Index for Assessing Heavy Metal Risks in Freshwater Sediments: Application to Inle Lake, Myanmar (Indo-Burma biodiversity hotspot)
(Springer, 2026-01) Rosado Alcarria, Daniel; Peters, Kristin; Phyo, Ei Wai; Kyi, Cho Cho Thin; Zin, Win Win; Fohrer, Nicola; Ingeniería Química y Ambiental
Metals in water and sediments of aquatic ecosystems pose significant ecological risks. However, existing methods to integrate and effectively communicate the overall toxicity risks of multiple metals are limited. This study introduces a toxicity factor (Tf) and toxicity index (TI) to comprehensively evaluate and communicate sediment metal pollution and associated risks to biota in a single figure. Furthermore, they are applied to Inle Lake, Myanmar, a crucial component of the Indo-Burma biodiversity hotspot, impacted by untreated sewage, uncontrolled waste disposal, agriculture, and artisanal mining. Sediment metal concentrations (mg/kg) decreased in the order Al (mean: 16,049) > Fe (11,191) > Mn (411) > Cr (34.7) > Zn (33.2) > Pb (22.4) > Ni (14.9) > As (9.69) > Cu (8.17) > Se (1.83). Contamination factor analysis indicated very high pollution by Al (6.99), considerable pollution by Cr (5.26), Pb (4.85), Ni (4.50), Cu (3.64), and Fe (3.09), and moderate pollution by Zn, Se, Mn, and As. The pollution load index (PLI) was highest (7.26) downstream of textile-weaving industries (site S1). Tf analysis identified possible toxicity risks for As, Cr, Ni, and Pb at points S1 and S5, while TI values (S1: 0.99; S5: 0.90) suggested these points were close to the threshold of possible toxicity. Acid-extractable fractions according to BCR-701 protocol revealed lower bioavailability of Cr despite its elevated total concentration, suggesting a primarily lithogenic source. Metal uptake by water hyacinth exhibited no direct correlation with sediment levels, emphasizing variability in metal bioavailability within the lake ecosystem.

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