The development and optimisation of silica-cork aerogel composites, prepared with tetraethyl orthosilicate (TEOS) and vinyltrimethoxysilane (VTMS) as co-precursors and reinforced with short cut aramid fibres is herein presented. Different synthesis parameters, such as co-precursor ratio, amount of fibres, and cork granulate dimensions, were investigated using a design of experiments approach to obtain composites with lower bulk densities and thermal conductivities. The obtained materials presented densities ranged from 0.140 to 0.190 g cm−3 and thermal conductivities in the superinsulation range (16.6–19.1 mW m−1K−1). These features, combined with their flexibility and thermal stability up to 300 °C, make the produced composites promising candidates for high-end applications in the automotive, buildings, and space industry, where high-performance insulation materials are needed. Also, the produced samples present sound absorption performance which expands their applicability to double barrier purpose, for heat and sound. Moreover, the composites exhibited excellent flame resistance after a qualitative test, even achieving flame extinction, positioning them as promising candidates for applications in the building industry. By utilizing renewable cork resources and improving energy efficiency, these materials can contribute to the reduction of environmental impact of insulator materials and will promote sustainable development in multiple sectors.

Aerogels were produced exclusively from recycled plastic bottles of poly(ethylene terephthalate) (rPET) by optimising a dissolution–precipitation process at room temperature and applying a product design strategy to improve their sustainability. Using a design of experiments methodology, the systematic assessment of the influence of different factors, namely rPET concentration, co-solvent ratio, and non-solvent quantity, on the key properties of rPET aerogel, namely bulk density, thermal conductivity, and mechanical resistance, was performed. The understanding of the significance of each parameter and the optimisation of a desirability function offered reliable optimum results for the adjustment of the experimental procedure for the reduction in the volume of the most critical solvent, trifluoroacetic acid (TFA), by 42.5%. The observed bulk density values were excellent, down to 110 kg·m−3, and the thermal conductivity was in the range of conventional commercial insulators (38 mW·m−1·K−1), positioning this material as a real alternative to conventional thermal insulators. Also, to deeply understand the dissolution/precipitation phenomena, molecular dynamics simulations were conducted to support the experimental outcomes.

The growing demand for sustainable packaging has accelerated research on bio-based coatings for paper substrates, aiming to replace petroleum-derived barriers while maintaining functional performance. This review critically examines recent advances in biopolymers, nanomaterials and bionanocomposite coatings developed to improve paper's resistance to water, water vapour, oils/greases and gases. Particular attention is given to how material chemistry, coating architecture and processing conditions shape barrier functionality, supported by benchmark comparisons that place reported values within a consistent performance framework. The analysis highlights the selective strengths and persistent limitations of individual biopolymers and nanomaterials and shows how their integration into bionanocomposite structures enables broader and more balanced protection, including several formulations capable of triple- and quadruple-barrier performance. Persistent challenges, including formulation stability, drying behaviour, coating, scalability, and end-of-life performance are discussed in the context of their impact on industrial adoption. By assembling the literature into a unified barrier-performance landscape, this review provides a clear perspective on current capabilities and identifies the materials that will guide the development of robust, multifunctional coatings for next-generation paper packaging.

The exceptional properties of aerogels explain their growing applicability in different research areas. In the case of nutraceutical delivery, they hold the potential to improve the common challenges of poor bioavailability and low stability of the bioactive ingredients, thereby enhancing intestinal delivery. Starch aerogels offer additional attractive features: biocompatibility, potential cost reduction, and abundance of raw materials. This review explores the development of starch aerogels as carriers for nutraceutical delivery, and how it can be rationalized with molecular simulation. The fundamentals of starch aerogels and the existing literature on the carriers are explored, including synthesis procedure, morphology, nutraceutical loading, and characterization of the resulting delivery system. Molecular simulation is identified as a key tool for examining properties and interactions occurring at the nano- and sub-nanoscale. The current gaps in the field are critically discussed, and trending topics for future research are identified. A computational-assisted design combined with a systematic approach to production routes is needed to further develop the field of starch aerogels for nutraceutical delivery, in addition to assessing toxicity, stability during storage, and scale-up viability.

Approximately 1 billion tires are discarded globally each year, a figure that is expected to continue rising over the next decade. When end‑of‑life tires (ELTs) are poorly managed, they can become a major source of environmental pollution, posing risks to both terrestrial and marine ecosystems. In this research, and for the first time, gypsum composites incorporating a recycled rubber colloidal solution were developed. Three recycled-rubber weight percentages (2.5%, 5.0%, and 7.5%) were evaluated in the form of a conventional granulate and an innovative colloidal solution. Their performance was compared through physicochemical characterization, mechanical testing, water-absorption behaviour, fire and thermal analyses. A remarkable reduction in thermal conductivity—19% (−60 mW/m·K)—was achieved for the gypsum composite compounded with 7.5 wt% of recycled-rubber colloidal solution. This composite also presented a lower bulk density (up to −8%) compared with the reference homogeneous gypsum, which exhibited values of 324.1 mW/m·K and 1083 kg/m³ , respectively. In all the gypsum composites analysed, the minimum flexural breaking load of 0.18 kN for boards was exceeded. Additionally, good performance under fire exposure was observed, with no evidence of ignition, flaming particle drop, or significant mass loss. Furthermore, high-performance thermal break strips (TBSs) made of recycled tyre rubber-silica aerogel, were tested for the first time in a lightweight steel-framed (LSF) wall prototype. The combined use of the new colloidal rubber solution-gypsum boards and the new rubber-silica aerogel TBSs resulted in a substantial increase in the LSF wall’s thermal resistance (R-value)—up to + 40.9% (+0.669 m²·K/W).

Although ZnO nanoparticles (ZnO-NPs) are promising controlled-release Zn sources, the influence of synthesis route and precursor chemistry on Zn dissolution, leaching, and bioavailability in different soils remains unclear. This study compared five laboratory-synthesised ZnO formulations to determine how formulation design affects Zn mobility and availability in sand and soils. ZnO-NPs (C-NIT-1, C-SUL, C-NIT-2, S-ACE, and S-SUL) were synthesised via co-precipitation or sol–gel routes using different precursors and hydroxide sources, yielding distinct physicochemical properties. Dissolution was assessed in aqueous media, and leaching was evaluated through column experiments with sand, acidic soil (pH 5.8), and calcareous soil (pH 8.3). Zinc in leachates was periodically quantified, and bioavailable Zn was determined using low-molecular-weight organic acids. The formulations showed marked differences in structural and surface properties, with hydrodynamic diameters of 183–603 nm and zeta potentials from − 7.4 to + 16.5 mV. SEM revealed variable aggregation, with C-NIT-2 forming aggregates up to 10 μm. Elemental analysis confirmed precursor-dependent variation in S and Zn contents. These differences resulted in contrasting Zn release patterns: in sand, C-SUL and S-ACE released Zn rapidly, whereas C-NIT-1 and S-SUL showed slower kinetics. In acidic soil, C-SUL leached 1.4 mg Zn (> 80

Many industries largely use perand polyfluoroalkyl substances (PFAS). However, their removal from process effluents has been a major concern due to their spreading and accumulation in soils and water. This work aims to investigate the adsorption of PFAS through silica-based aerogels as an alternative method for removing PFAS at high concentrations in effluents. Two silica-based aerogel adsorbents were synthesized from a combination of silanes, one having hydroxyl and methyl groups in the silica structure and the other having additional amine groups. These were used for the removal of selected PFAS, namely perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorobutane sulfonic acid (PFBS), covering different chain lengths and polar groups. The amine-modified adsorbent showed superior performance for uptake PFAS, since the amine protonation at pH 6 water allows additional electrostatic interactions with the PFAS. This aerogel effectively contributed to the removal of concentrated solutions of the long-chain PFAS. For the short-chain PFAS (PFBS), the amine-containing aerogel performed better in the lowest concentration tested (5 mg L-1). The variation of adsorbent loads (1.4-10 g L-1) did not significantly impact the removals achieved for the PFOA and PFOS with the amine-modified aerogel (93-99%). For the PFBS, the removals were around 60%, achieving a maximum of 75%. The adsorption kinetics showed a very fast adsorption of the PFAS by aerogel, reaching the equilibrium within the first few minutes of contact. Furthermore, a cumulative adsorption test showed that the amine aerogel did not reach saturation when exposed to 4 cycles of high concentration of PFOS.

In this work, a straightforward method to produce aerogels from recycled poly(ethylene terephthalate) (rPET) drinking water bottles is presented. It consists of dissolving the rPET, followed by precipitation and subsequent gelation, after which the aerogel is obtained by freeze-drying. Three types of rPET aerogels, unreinforced and reinforced with organic or inorganic fibers, were prepared using this method. The obtained aerogels have a porosity between 80 and 86% and a bulk density between 150 and 210 kg/m(3). The resulting materials have good mechanical properties, with a Young's modulus between 1.5 and 3.5 MPa, and do not release particles when handled. They also show thermal insulation capability at the level of commercial thermal insulators (similar to 20-65 mW m(-1) K-1). The observed presence of macropores in the predominantly mesoporous structure can be useful for sound absorption. The developed aerogels represent a unique opportunity to value plastic waste by producing an advanced material, following the principles of circular economy.

Biogenic amines (BAs) are potentially harmful biomolecules, formed during food degradation by microorganisms, which represent an issue in the food sector. The evaluation of such molecules in foods needs to be assessed by employing simple and low-cost devices to be used in a practical way in quality control operations. This work reports a sensor platform based on a lanthanide-doped silica film that uses 4,4,4-trifluoro-1-phenyl-1,3-butanedione (BTFA), a diketone molecule, as antenna. Using paper as a sensor film substrate, cheap sensors were obtained for the detection and discrimination of numerous amines, with a special emphasis on BAs. By using BTFA as an antenna, significant and fast changes in emission colour were observed after the sensor exposure to amine vapours. The sensor displays characteristic colours for different amines, which results from significant differences in the Eu3+/Tb3+ emission intensity ratios. The obtained combined colours response, allows an accurate amine differentiation, either visual or spectroscopic. The sensor was applied to real samples to identify the degradation process of fresh fish, resulting in notable changes during the studied period.

In the synthesis of aerogels, the influence of the drying process on the nanostructure is an issue of utmost relevance for tailoring the final properties of these materials. Among the complex parameters affecting this process, the hydrophobicity of the aerogel structure plays a key role. Thus, herein, four different silica aerogel formulations based on tetraethyl orthosilicate and trimethoxymethylsilane were employed to produce aerogels with different wettability properties (from hydrophilic samples to highly hydrophobic). The synthesized gels were dried by three methods, namely freeze-drying, high-temperature supercritical drying with ethanol, and low-temperature supercritical drying with carbon dioxide, and the influence of each procedure on bulk density, porosity, pore size, and specific surface area of the resulting aerogels was analyzed in detail. The direct correlation between the surface hydrophobicity/hydrophilicity of the silica gels and the effects of each drying technique was analyzed, providing insights into a proper selection of the drying method depending on both the water affinity of the gel and the desired textural properties and structures.

Amines are ubiquitous in living organisms and play essential roles in various physiological functions, including neurotransmission, hormonal regulation, cell signalling, and metabolism. In daily life, amines are found in cosmetics, pharmaceuticals, and foods. However, biogenic amines, formed through amino acid decarboxylation during food degradation, present a significant health risk, especially when combined with nitrites and nitrates in foods. Therefore, stringent control measures are essential. Thus, the development of user-friendly sensor devices for on-site monitoring of these molecules is a crucial area of research, because limited portable and simple options for amine detection and quantification are currently available. Electrochemical sensors offer an attractive solution for reliable and sensitive on-site measurements. With these sensors it is possible to carry out measurements, without complex sample processing. This review provides an overview of advancements in electrochemical sensors for detecting and quantifying various amines, highlighting the potential of different sensor configurations, sensing elements, and underlying detection mechanisms.

Yttria‐tetragonal‐stabilized zirconia (YSZ) and alumina are common ceramics used in dental aesthetics/prosthetics. Their combination leads to composites with improved mechanical strength and toughness. In this work, different amounts of alumina are added to YSZ by mechanosynthesis to study the influence on the microstructural, mechanical, and aging properties of the blended nanocomposites. Moreover, a comparison with the properties of nanocomposites prepared by sol–gel method is also performed. For both cases, ≈3 mol% of yttria in zirconia proves to be an adequate amount to stabilize the tetragonal and cubic phases of zirconia at environmental temperature, with only low amounts of the monoclinic phase present. Vickers microhardness (HV) and scratching tests show that the nanocomposites with 3 mol% of alumina exhibit better mechanical properties, considering the aimed potential application as dental ceramics, even when the materials are subjected to low‐temperature degradation in artificial saliva. In fact, they can preserve their good toughness and HV, as well as the constituent crystalline phases under these accelerated degradation conditions.

The inclusion of different fillers in silica aerogels reinforced by a reticulated polyurethane skeleton, allows for the development of a strategy to obtain composites with superior characteristics. Different fillers (TiO2, GO, SiC) and contents (0.2, 0.5 and 1.0 wt.%) were explored, analyzing their effects on the porous structures, mechanical stiffness and thermal conductivity of the composites. These exhibited low densities, reduced shrinkage, and high specific surface areas of approximately 550 m2/g. The incorporated fillers were homogeneously dispersed, leading to a general decrease in the mean pore size. Despite observing a slight reduction in the elastic modulus with respect to the non-doped composite, the benefits of this strategy are twofold; the composites can withstand strains above 80 % without breaking, significantly improving the mechanical stability when compared to non-reinforced silica aerogels, and while achieving high resilience. Additionally, enhanced thermal insulating performance was found for some materials. After analyzing the heat transfer contributions, the optimum particle contents for an improved thermal insulation were identified (1.0 wt.% TiO2 and 0.2 wt.% SiC), leading to an effective reduction of the radiation term and reaching overall reductions of 10 and 6.5 % at 100 °C. Therefore, the silica aerogel-based composites herein produced represent a step forward in their usability and versatility for cutting-edge applications.

Aerogels are exceptionally lightweight materials characterized by their high open porosity and remarkable specific surface area, currently used across a wide array of industrial sectors from construction to energy storage and have great potential for expanding their applicability and unlocking new market opportunities. Driven by global economic growth and an intensifying environmental crisis, there is a growing demand for engineering innovations that prioritize sustainability. Aerogels are well-positioned to support these sustainability efforts. Their unique properties make them ideal for energy-saving solutions, environmental remediation, and more efficient use of resources. As the demand for eco-conscious technologies rises, aerogels are poised to contribute significantly to the development of greener, more efficient products and processes across multiple industries. The sustainability of aerogel technology is crucial for the mid-to-long-term future, yet its current status has been scarcely reviewed in the literature. This Perspective explores and critically reviews significant advances on organic and hybrid aerogels in the current socioeconomic scenario, with selected case studies endorsing their contribution to the UN Sustainable Development Goals. It also identifies research gaps while proposing innovative strategies to enhance the sustainability of aerogel production through the application of circular economy principles. Key strategies discussed involve the fabrication of aerogels using eco-friendly sources, such as biopolymers derived from biorefinery processes or from waste materials. Additionally, this Perspective examines the development of methods for the reuse, recycling, and end-of-life management of aerogels, along with the implementation of more efficient processing routes. Ultimately, this work highlights the need for comprehensive assessments of aerogel sustainability through life cycle assessment (LCA) and evaluations of safety and toxicity. By addressing these critical aspects, the potential of aerogels to contribute to a more sustainable future appears highly favorable from both commercial and research perspectives, paving the way for a circular aerogel economy and providing a lasting impact to the society in which we live.

Strength properties of paper with lignin-containing microfibrillated cellulose (LMFC) were investigated under industrial conditions. To achieve this, a conical refiner was used to fibrillate unbleached eucalyptus kraft pulp fibers with low lignin content (LYP) and with high lignin content (HYP). Additionally, industrial white-water samples collected at the beginning and at the end of a paper production run were used in refining and handsheet preparation processes. Comparing the two types of pulp, HYP exhibited superior internal bond strength properties than LYP, attributed to the increased relative bonded area due to the presence of lignin. The introduction of LMFC (at 5 and 10% w/w) derived from both LYP and HYP resulted in significant enhancements in the tensile index, with increases of 34% and 52%, and 26% and 39%, respectively, when tested in demineralized water. Furthermore, it was observed that the white-water with a high cationic demand diminished paper strength, while the white-water with lower fine content enhanced these properties. Notably, the type of water used had a more significant impact on strength properties than the presence of microfibrillated cellulose, although the addition of microfibrillated cellulose improved tensile strength consistently. Alongside strength characteristics, the influence on other paper properties such as structure, oil and water barrier, and optical properties were also examined.

In this work, a potentiometric sensor for the detection of biogenic amines (BAs) in food samples was developed and characterised. The sensor employs a home-fabricated electrode incorporating a cucurbit[6]uril-modified polyvinyl chloride membrane as the sensing element. The working principle, system behaviour, and optimal operational conditions for BA monitoring were systematically investigated. The developed sensor demonstrated excellent analytical performance, showing a linear response in the concentration range of 3.0 × 10−5 to 1.0 × 10−2 mol L−1, with a low limit of detection of 2.4 × 10−5 mol L−1. Among the tested analytes, the sensor exhibited the highest sensitivity toward tyramine. These results highlight the potential of the proposed cucurbit[6]uril-based potentiometric sensor as an effective and reliable tool for monitoring BAs in complex food matrices, contributing to improved food safety, quality control, and spoilage prevention in the food industry, while also demonstrating its new application as a low-cost, easily constructed platform for rapid tyramine screening in food products.

Safe water supply has become one of the main concerns of our society due to the intense industrial activities generating hazardous waste. Among the water pollutants, copper ions are known for potential diseases caused by accumulation of this metal. Therefore, different adsorbents have been produced for this purpose, highlighting aerogels for their effective adsorption owing to their high surface areas and porosity. Herein the synthesis of a novel silica aerogel-based composite for copper removal is described. It was produced by the sol-gel technique, synthesizing the silica aerogel into a reticulated-polyurethane foam that acted as a macrocellular skeleton, preventing a strong shrinkage of the aerogel during the ambient pressure drying. The produced aerogels and composites were characterized in terms of density, textural properties, hydrophobicity, and copper removal efficiency. Isotherm studies revealed a significantly improved adsorption capacity in comparison with the monolithic aerogel, reaching a maximum value of 46.13 mg g- 1. The predominant adsorption mechanism was Langmuir- Freundlich adsorption. The adsorption kinetics were also evaluated by different models, as well as the ability to function as filtration medium. Therefore, this work provides a promising strategy for copper uptake avoiding tedious filtration steps to separate the adsorbent, thus reducing time and costs.

In this study, an electrochemical method is presented for the direct determination of tyramine in beer samples. A multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) was developed for the detection and quantification of tyramine at a low potential of 0.53 V. The electrochemical process and sensor parameters were thoroughly investigated to establish optimal analysis conditions. The method demonstrated a linear response range from 3 to 9 µM, with a limit of detection (LOD) of 0.34 µM and a limit of quantification (LOQ) of 1 µM. The developed sensor was successfully applied to commercial beer samples for tyramine analysis. The results were compared with those obtained using the standard high-performance liquid chromatography (HPLC) technique, highlighting the sensor’s potential for tyramine determination in aqueous food samples without the need for complex sample preparation.

Lignin-containing microfibrillated cellulose (LMFC) has shown great potential for improving paper strength; however, its application under industrial conditions remains underexplored. This study investigates the effect of mechanically produced LMFC on paper properties in the presence of industrial white-water and examines how varying chitosan amounts can modify white-water properties to further improve these properties. The addition of 3

In recent years, there has been a challenging interest in developing low-cost biopolymeric materials for wastewater treatment. In the present work, new adsorbents, based on different types of chitosan (commercial, commercial chitin-derived chitosan and chitosan synthesized from shrimp shell waste) and inorganic–organic composites have been evaluated for copper ions removal. The efficacy of the synthesis of chitosan-based composite beads has been determined by studying various characteristics using several techniques, including FTIR spectroscopy, X-ray diffraction, porosimetry (N2 adsorption), and scanning electron microscopy (SEM). Adsorption kinetics was performed using different adsorption models to determine the adsorption behavior of the materials in the aqueous media. For all composite beads, regardless of the type of chitosan used, good capacity to remove copper ions from simulated waters was observed (up to 17 mg/g), which proves that the new materials hold potential for heavy metal retention. However, the adsorption efficiency was influenced by the type of chitosan used. Thus, for the series where commercial chitosan (CC) was used, the removal efficiency was approximately 29%; for the series with chitosan obtained from commercial chitin (SC), the removal efficiency was approximately 34%; for the series with chitosan enriched with CaCO3 (SH), the removal efficiency was approximately 52%.