Artículos (Ingeniería Química)

URI permanente para esta colecciónhttps://hdl.handle.net/11441/53665

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Thermoreversible oleogelation of fatty acid monoglyceride-containing sunflower oil from a rheological approach
(Elsevier, 2024-08) López González, Yolanda; Aguilar García, José Manuel; Ruiz Domínguez, Manuela; Guerrero Conejo, Antonio Francisco; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Nowadays, there is a growing concern among consumers about the impact of diet on health. In this regard, oleogelation has been proposed as a promising strategy to replace unhealthy fats, as well as to encapsulate water-insoluble bioactive compounds in food matrices. Consequently, the development of thermoreversible oleogels may play an important role in the bioavailability and biostability of functional foods and the beneficial effects associated with them. The aim of this work was to evaluate the viscoelastic behavior of oleogels using a commercial food additive (E471) composed of fatty acid monoglycerides (MG). Furthermore, the study of sol-gel transitions of these thermoreversible oleogels allowed to obtain the optimum concentration of gelling agent required. Refined sunflower oil containing 2–5 wt% of E471 were characterized by means of SAOS tests, as a function of temperature. All these systems were liquids above 48 °C, forming stable oleogels below 20 °C. An improvement of the elastic component of them was observed as gelling agent concentration was higher. Oleogels containing 4 and 5 wt% MG showed very similar viscoelastic properties and high stability at body temperature (ca. 37 °C). Conversely, systems containing 2% or 3% led to the formation of weaker gels exhibiting thermo-reversibility but only the latter was stable at body temperature. Therefore, sunflower oleogels containing MG above 3 wt% could be regarded as potential carrier food matrices for lipid-soluble active ingredients. To this end, the modulation of the oleogel network consistency should play a key role in maintaining the integrity of the active principle during gastrointestinal transit.
Assessment of the Processing Method for the Development of Hybrid Biopolymer-Based Scaffolds
(LIDSEN Publishing Inc, 2020-02-26) Alonso González, María; Rubio Valle, José Fernando; Pérez-Puyana, Víctor Manuel; Jiménez-Rosado, Mercedes; Romero García, Alberto; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economía y Competitividad (MINECO). España; European Union (UE)
The present study deals with the development of scaffolds based on gelatin (G) and/or chitosan (CH) through modifications in the central processing method. This process consists of the fabrication of a hydrogel which is, then submitted to a freeze-drying stage. To compare the effects of the different modifications, the mechanical properties of the various systems were characterized, employing both dynamic compressive strain and frequency sweep tests. In addition, their porosity as well as the structure and fiber distribution, using an analytic model and scanning electron microscopy (SEM), were also evaluated. The obtained results demonstrated a strong dependence on the properties by the scaffolds with both the modifications introduced in the processing method as well as the proportion of materials used (G and CH). Furthermore, the properties were found to improve for systems with a high chitosan content after being submitted to a heat treatment at 50 °C with agitation.
Effect of enzymatically hydrolysed brewers’ spent grain supplementation on the rheological, textural and sensory properties of muffins
(Elsevier, 2021-12) Cermeño, Maria; Dermiki, Maria; Kleekayai, Thanyaporn; Cope, Lydia; McManus, Rebecca; Ryan, Chloe; Félix Ángel, Manuel; Flynn, Cal; FitzGerald, Richard J.; Universidad de Sevilla. Departamento de Ingeniería Química; Department of Agriculture, Food and Marine. Ireland; Disruptive Technologies Innovation Fund (DTIF). Ireland; Ministerio de Ciencia e Innovación (MICIN). España
Brewers’ spent grain (BSG) is the major co-product of the brewing industry having a high content of protein and fibre. Enzymatic modification improves the properties of different ingredients when they are incorporated into confectionary products. This study characterised the rheological, textural and sensory properties of unmodified BSG (BSGA) and enzymatically modified BSG (BSGB, i.e., proteinase and carbohydrase modified BSG) when substituted at different levels (5, 10 and 15%) in a muffin ingredient mix. Rheological assessment showed a lower viscosity for the BSGB compared to the BSGA batters. Baked BSGB containing muffins had lower hardness values compared to BSGA and control without added BSG. Sensory assessment showed no significant differences in liking of the different attributes tested (overall appearance, texture, smell, colour and taste) between the 5% BSGA and BSGB supplemented muffins. Incorporation of BSGB at 10% had no negative impact on the sensory attributes in comparison to BSGA 10%. Overall, low level substitution of enzymatic modified BSG beneficially reduced batter viscosity and muffin hardness and gave comparable sensory attributes to those of unmodified BSG supplemented muffins. Therefore, prior enzymatic modification can enhance the ingredient functionality of BSG in confectionary products.
Cp2TiCl is a useful reagent to teach multidisciplinary chemistry
(National Autonomous University of Mexico, Faculty of Chemistry, 2021-10-04) Rosales Martínez, Antonio; Universidad de Sevilla. Departamento de Ingeniería Química; Junta de Andalucía
Cp2TiCl is a single electron transfer reagent which has contributed to several field of scientific knowledge, such as organic, inorganic, green and analytical chemistry. In this article the main reviews and some primary chemical literature is converted to a brief manuscript that serves to illustrate how a reagent can be used to teach multidisciplinary chemistry to undergraduate chemists and chemical engineers.
Comparative Effect of Antioxidant and Antibacterial Potential of Zinc Oxide Nanoparticles from Aqueous Extract of Nepeta nepetella through Different Precursor Concentrations
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Fodil, Nouzha; Serra, Djaaboub; Abdullah, Johar Amin Ahmed; Domínguez Robles, Juan; Romero García, Alberto; Abdelilah, Amrouche; Universidad de Sevilla. Departamento de Farmacia y Tecnología Farmacéutica; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia e Innovación (MICIN). España
Antibiotic resistance is a global health crisis caused by the overuse and misuse of antibiotics. Accordingly, bacteria have developed mechanisms to resist antibiotics. This crisis endangers public health systems and medical procedures, underscoring the urgent need for novel antimicrobial agents. This study focuses on the green synthesis of ZnO nanoparticles (NPs) using aqueous extracts from Nepeta nepetella subps. amethystine leaves and stems, employing different zinc sulfate concentrations (0.5, 1, and 2 M). NP characterization included transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD), along with Fourier transform infrared spectroscopy (FTIR) analysis. This study aimed to assess the efficacy of ZnO NPs, prepared at varying concentrations of zinc sulfate, for their capacity to inhibit both Gram-positive and Gram-negative bacteria, as well as their antioxidant potential using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. SEM and TEM results showed predominantly spherical NPs. The smallest size (18.5 ± 1.3 nm for leaves and 18.1 ± 1.3 nm for stems) occurred with the 0.5 M precursor concentration. These NPs also exhibited remarkable antibacterial activity against both Gram-positive and Gram-negative bacteria at 10 µg/mL, as well as the highest antioxidant activity, with an IC50 (the concentration of NPs that scavenge 50% of the initial DPPH radicals) of 62 ± 0.8 (µg/mL) for the leaves and 35 ± 0.6 (µg/mL) for the stems. NPs and precursor concentrations were modeled to assess their impact on bacteria using a 2D polynomial equation. Response surface plots identified optimal concentration conditions for antibacterial effectiveness against each species, promising in combating antibiotic resistance.
Wine lees: From waste to O/W emulsion stabilizer
(Elsevier, 2021-12) Félix Ángel, Manuel; García Martínez, Inmaculada; Sayago, Ana; Fernández Recamales, Maria Ángeles; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla; Junta de Andalucía
Wine lees are the major waste from wine production, containing a noticeable amount of biomass (yeast, stalks, and peels), they could be used for the stabilization of dispersed systems such as emulsions. This work is focused on the determination of techno-functional properties of whine less produced from white grapes and industrial-grade blueberries. The interfacial characterisation was carried out by means of dilatational and interfacial shear rheology, whereas the characterisation of emulsion microstructure was assessed by droplet size distribution, rheological characterisation and backscattering measurements. The results obtained indicated that a high amount of polyphenols were present in wine less obtained from grape fermentation with industrial-grade blueberries as an additive, moreover, their presence also caused better interfacial properties (reducing the interfacial tension up to ca. 15 mN/m). However, the comparison of dilatational and interfacial-shear rheology determined that the interfacial response was caused by a densely packed structure. Fairly low droplet sizes (⁓ 320 nm) were obtained after ultraturrax® homogenization and further passing through the Microfluidizer® device, where the emulsions were stable only in presence of xanthan gum (0.06, 0.12 and 0.25 wt%). However, the suitable amount of XG gum was 0.06 and 0.12 wt% since no phase separation was observed in the emulsions generated over storage time, although flocculation phenomena took place. The results obtained exhibited emulsions with a suitable texture for the preparation of milk-shakes and brewages products, evidencing the potential of wine lees for these products.
Chitosan–Type-A-Gelatin Hydrogels Used as Potential Platforms in Tissue Engineering for Drug Delivery
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-07) Mehdi-Sefiani, Hanaa; Granados-Carrera, Carmen María; Romero García, Alberto; Chicardi Augusto, Ernesto; Domínguez Robles, Juan; Pérez-Puyana, Víctor Manuel; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Universidad de Sevilla. Departamento de Farmacia y Tecnología Farmacéutica; Universidad de Sevilla; European Union (UE); Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes; Universidad de Sevilla. TEP973: Tecnología de Polvos y Corrosión; Universidad de Sevilla. CTS547: Caracterización y Optimización Estadística de Medicamentos
Hydrogels are materials made of crosslinked 3D networks of hydrophilic polymer chains that can absorb and retain significant amounts of water due to their hydrophilic structure without being dissolved. In relation to alternative biomaterials, hydrogels offer increased biocompatibility and biodegradability, giving them distinct advantages. Thus, hydrogel platforms are considered to have the potential for the development of biomedical applications. In this study, the main objective was the development of hybrid hydrogels to act as a drug delivery platform. These hydrogels were made from chitosan (CH) and type A gelatin (G), two natural polymers that provide a supportive environment for cellular attachment, viability, and growth, thanks to their unique properties. Particularly, the use of gelatins for drug delivery systems provides biodegradability, biocompatibility, and non-toxicity, which are excellent properties to be used in the human body. However, gelatins have some limitations, such as thermal instability and poor mechanical properties. In order to improve those properties, the aim of this work was the development and characterization of hybrid hydrogels with different ratios of CH–G (100–0, 75–25, 50–50, 25–75, 0–100). Hydrogels were characterized through multiple techniques, including Fourier transform infrared (FTIR) spectroscopy, rheological and microstructural studies, among others. Moreover, a model hydrophilic drug molecule (tetracycline) was incorporated to evaluate the feasibility of this platform to sustain the release of hydrophilic drugs, by being tested in a solution of Phosphate Buffer Solution at a pH of 7.2 and at 37 °C. The results revealed that the synergy between chitosan and type A gelatin improved the mechanical properties as well as the thermal stability of it, revealing that the best ratios of the biopolymers are 50–50 CH–G and 75–25 CH–G. Thereby, these systems were evaluated in a controlled release of tetracycline, showing a controlled drug delivery of 6 h and highlighting their promising application as a platform for controlled drug release.
Extraction and Characterization of Carboxymethylcellulose from Cocoa Pod Husk
(Springer, 2024-08) Cevallos, Andrea; Bengoechea Ruiz, Carlos; Aguilar García, José Manuel; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Cocoa pod husk (70-75 wt.% of the fruit) is a waste that can be used containing cellulose (c.a. 35.4%). The present work evaluates the valorization of cocoa pod husk as a potential source of cellulose to obtain carboxymethylcellu-lose. A yield of 21.9% of extracted cellulose was obtained with respect to the cocoa husk flour used. Different procedures were applied to obtain carbox-ymethylcellulose (CMC), followed by a purification process, achieving a yield of 64.3%. The physical characterization of the CMC obtained was carried out using FTIR spectroscopy, and its molecular weight (183628.89 g/mol) was de-termined by its intrinsic viscosity. The CMC dispersions were tested using small amplitude oscillatory shear (SAOS) for concentrations 3-7%, finding an evolu-tion in the rheological behavior of the systems studied.
Monitoring of volatile fatty acids during anaerobic digestion of olive pomace by means of a hand held near infrared spectrometer
(Elsevier, 2024-12) Jiménez Páez, Elena; Ding, F.; González Fermoso, Fernando; García-Martín, Juan Francisco; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Economia, Industria y Competitividad (MINECO). España
The accumulation of volatile fatty acids (VFAs) over anaerobic digestion (AD) leads to malfunctioning of industrial reactors, hence decreasing biogas production. Real-time monitoring of VFAs is a challenge due to the complexity and high cost of current methods for their quantification. For this reason, this research evaluated the application of near infrared (NIR) spectroscopy to quantify volatile fatty acids as a tool for AD reactors monitoring. To do that, 129 samples from various AD reactors fed with olive oil pomace were taken and their NIR spectra were acquired with a hand-held spectrometer. After performing grid search, three spectral variable selection methods, namely competitive adaptive reweighted sampling, uninformative variable elimination (UVE) and successive projections algorithm, were assayed before developing PLRS models to correlate the NIR light transmittance through the samples at the wavelengths selected by those methods with their VFAs concentrations. UVE led to the best performance for all the VFAs assayed. Thus, R2 of validation of UVE-PLSR models for acetic, propionic, butyric, valeric and total VFAs were 0.895, 0.622, 0.866, 0.898 and 0.871, respectively. The predictive model for total VFAs achieved the highest accuracy (RMSEV = 539.5 mg/L), explained by the correlation between the light absorption at the wavelengths selected by UVE and the chemical characteristics of VFAs. All in all, the prediction errors achieved suggest that a portable near infrared spectrometer can be used for monitoring VFAs in AD processes.
Modelling of drying kinetics and comparison of two processes: Forced convection drying and microwave drying of celery leaves (Apium graveolens L.)
(Galati University Press, 2019) Mouhoubi, Khokha; Boulekbache-Makhlouf, Lila; Guendouze-Bouchefa, Naima; Freidja, Mohamed Lamine; Romero García, Alberto; Madani, Khodir; Universidad de Sevilla. Departamento de Ingeniería Química; Ministry of Higher Education and Scientific Research of Algeria
The purpose of this work is to compare two processes: forced convection drying and microwave drying of celery leaves (Apium graveolens L.). This comparison is based on kinetical parameters, moisture diffusivity, variation of the drying rate and energy consumption calculation of both processes. The drying experiments were carried out at different air temperatures(40-120 °C) and at different microwave powers (100-1000 W).Twenty-two empirical models were used to simulate the thin-layer drying kinetics of celery leaves and the best models were selected using three statistical criteria (R2, χ2 and RMSE). Sledz’s model proved to be the best for celery leaves drying kinetics description with 0.9962 ≤ R2 ≤ 0.9992, 0.000065 ≤ χ2 ≤ 0.000284 and 0.007979 ≤ RMSE ≤ 0.016683 for all the studied temperatures and 0.9971 ≤ R2 ≤ 0.9989, 0.000124 ≤ χ2 ≤ 0.000291 and 0.010910 ≤ RMSE ≤ 0.016914 for all the used powers. Moisture effective diffusivity ranges from 2.22×10-12 to 6.40×10-11 for convective drying and from 1.18×10-11 to 3.13×10-10 m2/s for microwave drying. While in the same order, the activation energies were 36.09 kJ/mol and 77.3 W/g. Regarding the energy consumption, the Specific Electrical Energy Consumption decreased with decreasing temperature or power levels, whereas the opposite was observed with Energy Efficiency. It is clear that many advantages are attributed to microwave drying, including reduced drying time, high drying rate and high moisture diffusivity, low energy consumption and significant drying efficiency, especially when power levels are high.
Unveiling the Impact of Gelation Temperature on the Rheological and Microstructural Properties of Type A Gelatin Hydrogels
(MDPI, 2024) Mehdi-Sefiani, Hanaa; Chicardi Augusto, Ernesto; Romero García, Alberto; Pérez-Puyana, Víctor Manuel; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. Departamento de Ingeniería y Ciencia de los Materiales y del Transporte; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla
Gelatin-based hydrogels have garnered significant attention in the fields of drug delivery systems and tissue engineering owing to their biodegradability, biocompatibility, elasticity, flexibility and nontoxic nature. However, there is a lack of information regarding type-A-gelatin-based hydrogels. In this sense, the main aim of this work was the evaluation of the properties of type-A-gelatin-based hydrogel achieved using two different gelation temperatures (4 °C and 20 °C). Thus, the main novelty of this study lies in the analysis of the impact of gelation time on the rheological and microstructural properties of type-A-gelatin-based hydrogels. Moreover, the addition of a drug was also analyzed in order to evaluate the hydrogels’ behavior as a drug delivery system. For this purpose, rheological (strain, frequency sweep tests and flow curves) and microstructural (SEM) characterizations were carried out. The results demonstrated that lowering the gelation temperature improved the rheological properties of the systems, obtaining hydrogels with an elastic modulus of 20 kPa when processing at 4 °C. On the other hand, the increase in the gelation temperature improved the critical strain of the systems at low temperatures. In conclusion, this work showed the feasibility of producing hydrogels with potential application in drug delivery with different properties, varying the testing temperature and incorporating tetracycline into their formulation.
Seaweed as Basis of Eco-Sustainable Plastic Materials: Focus on Alginate
(MDPI, 2024) Santana, Ismael; Félix Ángel, Manuel; Bengoechea Ruiz, Carlos; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia e Innovación (MICIN). España
Seaweed, a diverse and abundant marine resource, holds promise as a renewable feedstock for bioplastics due to its polysaccharide-rich composition. This review explores different methods for extracting and processing seaweed polysaccharides, focusing on the production of alginate plastic materials. Seaweed emerges as a promising solution, due to its abundance, minimal environmental impact, and diverse industrial applications, such as feed and food, plant and soil nutrition, nutraceutical hydrocolloids, personal care, and bioplastics. Various manufacturing techniques, such as solvent casting, injection moulding, and extrusion, are discussed for producing seaweed-based bioplastics. Alginate, obtained mainly from brown seaweed, is particularly known for its gel-forming properties and presents versatile applications in many sectors (food, pharmaceutical, agriculture). This review further examines the current state of the bioplastics market, highlighting the growing demand for sustainable alternatives to conventional plastics. The integration of seaweed-derived bioplastics into mainstream markets presents opportunities for reducing plastic pollution and promoting sustainability in material production.
Rice Bran Valorization through the Fabrication of Nanofibrous Membranes by Electrospinning
(MDPI, 2024) Alonso González, María; Félix Ángel, Manuel; Romero García, Alberto; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla
The high production rate of fossil-based plastics, coupled with their accumulation and low degradability, is causing severe environmental problems. As a result, there is a growing interest in the use of renewable and natural sources in the polymer industry. Specifically, rice bran is a highly abundant by-product of the agro-food industry, with variable amounts of protein and starch within its composition, which are usually employed for bioplastic development. This study aims to valorize rice bran through the production of nanofiber membranes processed via electrospinning. Due to its low solubility, the co-electrospinning processing of rice bran with potato starch, known for its ability to form nanofibers through this technique, was chosen. Several fiber membranes were fabricated with modifications in solution conditions and electrospinning parameters to analyze their effects on the synthesized fiber morphology. This analysis involved obtaining micrographs of the fibers through scanning electron microscopy (SEM) and fiber diameter analysis. Potato starch membranes were initially investigated, and once optimal electrospinning conditions were identified, the co-electrospinning of rice bran and potato starch was conducted. Attempts were made to correlate the physical properties of the solutions, such as conductivity and density, with the characteristics of the resulting electrospun fibers. The results presented in this study demonstrate the potential valorization of a rice by-product for the development of bio-based nanofibrous membranes. This not only offers a solution to combat current plastic waste accumulation but also opens up a wide range of applications from filtration to biomedical devices (i.e., in tissue engineering).
Development of rice bran-based bioplastics via injection molding: Influence of particle size and glycerol ratio
(Elsevier, 2024) Alonso González, María; Félix Ángel, Manuel; Romero García, Alberto; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia e Innovación (MICIN). España; Universidad de Sevilla
Plastics play a vital role in modern society but their non-biodegradable nature has led to environmental concerns. Biomass-derived biodegradable bioplastics offer an eco-friendly alternative and protein and starch-based bioplastics, sourced from agro-food residues, are gaining prominence due to their renewability. However, many bio-based materials face challenges and developing efficient processing methods is crucial for their industrial viability. Optimizing particle size and plasticizer proportion is vital to tailor the properties of bioplastics. This study evaluates rice bran-based bioplastics, produced via injection molding, considering particle size and the impact of glycerol ratio. Smaller particle sizes enhance interactions during processing and, the conditions achieved during mixing determined the relevance of biopolymer–plasticizer and biopolymer–biopolymer interactions, leading to different behaviors depending on their balance. The processability and final properties of the materials developed were also affected by the glycerol ratio, with higher rice bran proportion leading to better rheological and mechanical properties.
Modeling copper leaching from non-pulverized printed circuit boards at high concentrations of bioregenerated ferric sulfate
(Elsevier, 2024-10) Ramírez del Amo, Pablo; Iglesias González, María Nieves; Dorado, Antonio D.; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. TEP186: Biohidrometalurgia
This work studies the leaching of copper contained in waste printed circuit boards (PCB) with ferric sulfate, with the aim of improving the results found in the literature for an industrial application of the process. For this purpose, temperatures and concentrations of ferric ion higher than those of previous works (up to 60 °C and 40 g/L) are used. Furthermore, ferric sulfate can be continuously regenerated by ferro-oxidizing bacteria immobilized in a bioreactor, avoiding physical contact between waste and microorganisms to optimize independently operation conditions. A kinetic model was developed for the interpretation of the experimental results validated at different conditions. The model was based on a shrinking core model limited by mass transfer inside the PCB where the geometry and structure of the PCB has been considered and an excellent fit of the model to the experimental data was obtained. The connection with the bioreactor for biooxidation of the generated ferrous ion allows maintaining high concentrations of ferric when operating at high solid concentrations (5–10 %). In all the cases studied, more than 99 % of the copper contained in the non-pulverized PCB parts was dissolved in less than 24 h, with an average copper extraction rate of 0.6 g/L·h higher than those found in previous works.
From a Hazardous Waste to a Commercial Product: Learning Circular Economy in the Chemistry Lab
(American Chemical Society, 2024-07-30) Iglesias González, María Nieves; Ramírez del Amo, Pablo; Lorenzo Tallafigo, Juan; Universidad de Sevilla. Departamento de Ingeniería Química
We are currently facing a change in the production model, moving from the traditional linear model to a model based on circular economy. This new paradigm implies minimization of waste. In this context, this work presents a laboratory practice focused on introducing the concept of circular economy and waste valorization to undergraduate students. The experimental procedure is a simpler adaptation of earlier work by the research group in which metals were recovered from electric arc furnace dust (EAFD) and it is composed of four stages: acid leaching to dissolve the zinc, selective precipitation to eliminate dissolved iron, cementation to recover metals more noble than zinc, and finally obtaining basic zinc carbonate by precipitation. In this way, students can convert a residue into a valuable product while cleaning it, so that it can be reintroduced into the steel-producing process. Fourth year students of the Materials Engineering Degree at the University of Seville (Spain) have successfully performed this laboratory experiment since the 2015–16 academic year. In addition, to evaluate the achievement of the pedagogical objectives, pre- and postlaboratory questionnaires have been carried out in the past two academic years showing that more than 75% of the students improve their answers after performing the laboratory practices.
Characterization of emulgels formulated with phycocyanin and diutan gum as a novel approach for biocompatible delivery systems
(Elsevier, 2024-05) Tello, Patricia; Santos García, Jenifer; Pérez-Puyana, Víctor Manuel; Romero García, Alberto; Trujillo-Cayado, Luis Alfonso; Universidad de Sevilla. Departamento de Ingeniería Química; Ministerio de Ciencia e Innovación (MICIN). España
Phycocyanin (PC), a protein derived from algae, is non-toxic and biocompatible. Due to its environmental and sustainable properties, it has been studied as an alternative stabilizer for food emulsions. In this sense, the main objective of this work is to evaluate the effectiveness of PC and its use in combination with diutan gum (DG), a biological macromolecule, to prepare emulgels formulated with avocado oil. Z-potential measurements show that the optimum pH for working with PC is 2.5. Furthermore, the system exhibited a structured interface at this pH. The surface tension did not decrease further above 1.5 wt% PC. Interestingly, emulsions formulated with >1.5 wt% PC showed recoalescence immediately after preparation. Although 1.5 wt% had the smallest droplet size, this emulsion underwent creaming due to the low viscosity of the system. DG was used in combination with PC to increase viscosity and reduce creaming. As little as 0.1 wt% DG was sufficient to form an emulgel when incorporated into the previous emulsion, which exhibited pseudoplastic behaviour and viscoelastic properties with very low creaming rates. However, the use of PC in combination with DG resulted in a non-aggregated and stable emulgel with 1.5 wt% PC and 0.1 wt% DG.
Large-scale synthesis of 2D-silica (SiOₓ) nanosheets using graphene oxide (GO) as a template material
(Royal Society Chemistry, 2023-08) Birdsong, Björn K.; Hoogendoorn, Billy W.; Nilsson, Fritjof; Andersson, Richard L.; Capezza, Antonio J.; Hedenqvist, Mikael S.; Farris, Stefano; Guerrero Conejo, Antonio Francisco; Olsson, Richard T.; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla. TEP229: Tecnología y Diseño de Productos Multicomponentes
Graphene oxide (GO) was used in this study as a template to successfully synthesize silicon oxide (SiOₓ) based 2D-nanomaterials, adapting the same morphological features as the GO sheets. By performing a controlled condensation reaction using low concentrations of GO (<0.5 wt%), the study shows how to obtain 2D-nanoflakes, consisting of GO-flakes coated with a silica precursor that were ca. 500 nm in lateral diameter and ca. 1.5 nm in thickness. XPS revealed that the silanes had linked covalently with the GO sheets at the expense of the oxygen groups present on the GO surface. The GO template was shown to be fully removable through thermal treatment without affecting the nanoflake morphology of the pure SiOₓ-material, providing a methodology for large-scale preparation of SiOx-based 2D nanosheets with nearly identical dimensions as the GO template. The formation of SiOₓ sheets using a GO template was investigated for two different silane precursors, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS), showing that both precursors were capable of accurately templating the graphene oxide template. Molecular modeling revealed that the choice of silane affected the number of layers coated on the GO sheets. Furthermore, rheological measurements showed that the relative viscosity was significantly affected by the specific surface area of the synthesized particles. The protocol used showed the ability to synthesize these types of nanoparticles using a common aqueous alcohol solvent, and yield larger amounts (∼1 g) of SiOₓ sheets than what has been previously reported.
Large-scale synthesis of 2D-silica (SiOx) nanosheets using graphene oxide (GO) as a template material
(Royal Society of Chemistry, 2023-07-26) Birdsong, Björn K.; Hoogendoorn, Billy W.; Nilsson, Fritjof; Andersson, Richard L.; Capezza, Antonio J.; Hedenqvist, Mikael S.; Guerrero Conejo, Antonio Francisco; Olsson, Richard T.; Universidad de Sevilla. Departamento de Zoología
Graphene oxide (GO) was used in this study as a template to successfully synthesize silicon oxide (SiOx) based 2D-nanomaterials, adapting the same morphological features as the GO sheets. By performing a controlled condensation reaction using low concentrations of GO (<0.5 wt%), the study shows how to obtain 2D-nanoflakes, consisting of GO-flakes coated with a silica precursor that were ca. 500 nm in lateral diameter and ca. 1.5 nm in thickness. XPS revealed that the silanes had linked covalently with the GO sheets at the expense of the oxygen groups present on the GO surface. The GO template was shown to be fully removable through thermal treatment without affecting the nanoflake morphology of the pure SiOx-material, providing a methodology for large-scale preparation of SiOx-based 2D nanosheets with nearly identical dimensions as the GO template. The formation of SiOx sheets using a GO template was investigated for two different silane precursors, (3-aminopropyl) triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS), showing that both precursors were capable of accurately templating the graphene oxide template. Molecular modeling revealed that the choice of silane affected the number of layers coated on the GO sheets. Furthermore, rheological measurements showed that the relative viscosity was significantly affected by the specific surface area of the synthesized particles. The protocol used showed the ability to synthesize these types of nanoparticles using a common aqueous alcohol solvent, and yield larger amounts (∼1 g) of SiOx-sheets than what has been previously reported.
Cp₂TiCl is a useful reagent to teach multidisciplinary chemistry
(Universidad Nacional Autónoma de México (UNAM), 2021-10-04) Rosales Martínez, Antonio; Universidad de Sevilla. Departamento de Ingeniería Química; Universidad de Sevilla; Universidad de Sevilla. RNM932: Química e Ingeniería Sostenibles
Cp₂TiCl es un único reactivo de transferencia de electrones que ha contribuido en varios campos del conocimiento científico, como la química orgánica, inorgánica, ecológica y analítica. En este artículo, las revisiones principales y parte de la literatura química primaria se convierten en un breve manuscrito que sirve para ilustrar cómo se puede usar un reactivo para enseñar química multidisciplinaria a químicos e ingenieros químicos de pregrado.

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