Search Results (486)

Cyclodextrin-based nanosponges (CDNSs) are novel polymers composed of cross-linked cyclodextrin (CD) macrocyclic units, whose characteristics make them great candidates for drug delivery systems with adjustable properties for the drug release process. Examination of the molecular structure and dynamics of CDNSs is a necessary starting point in the first step toward their broad application. Spectroscopic methods are effective analytical tools for probing the structure–property relationships of polymer structures. Infrared (IR) and Raman spectroscopies provide insight into the behavior of hydrogen bond (H-bond) networks influencing the properties of CDNS polymeric networks. Scattering techniques such as inelastic neutron scattering (INS) and Brillouin light scattering (BLS) probe elastic properties, while small-angle neutron scattering (SANS) examines the structural inhomogeneities and water sorption abilities of CDNS materials. Complete evaluation is possible using nuclear magnetic resonance (NMR), which can provide data on CDNS network dynamics. This article summarizes the results of a wide examination of CDNSs with the use of spectroscopic methods and reveals the links between the microscopic behavior and macroscopic properties of CDNSs, enabling the customization of their properties for various biomedical purposes. Full article

Background/Objectives: The principal function of pharmaceutical blister packaging is to provide protection for the drug product. Moisture is regarded as a critical factor in the physical and chemical aging of drug products. The present work proposes a modeling framework to predict the performance of tablet blister materials based on the moisture uptake profile of the drug product as well as degradation characteristics of the drug substance, while the consumption of water due to degradation is included. Methods: The model incorporates three kinetic superimposed processes that define moisture uptake and drug stability. The processes of permeation, sorption and degradation are each described with a rate constant. Based on a mass balance, these rate processes are interconnected and the relative humidity in the blister cavity is predicted. Results: In a case study, the model was applied to demonstrate the feasibility of predicting the stability of blistered tablets. By establishing a correlation between the moisture uptake of the tablet and the drug stability demonstrated in the model, it was feasible to predict the drug content over shelf life. Conclusions: Modeling of the drug stability of blister-packed products enables a rational packaging which offers novel possibilities for reducing material in order to avoid overpackaging of pharmaceutical products. As some of the commonly used barrier materials are considered to not be sustainable, this model can be used to consider a rationally justified reduction or even abandonment of the barrier materials. Full article

The seed drying process is one of the most important aspects of post-harvest treatment, which determines the quality of the final product, cost accounting, and storage capacity. Sorption drying is of great scientific and practical importance due to its ability to gently remove moisture, which improves seed quality and ensures energy efficiency. In this study, wheat grains with an initial moisture content of 22% were dried to a moisture content of 13% using sorption, thermal, and natural air drying. The seed germination capacity after drying was 97%, 93%, and 95%, respectively. The effect of different drying methods on the morphological characteristics, microstructure, and moisture content of wheat grains was studied using a combination of experimental techniques. ATR-MIR and MAS NMR analysis revealed the biochemical stability of sorption-dried grains and the complete preservation of characteristic protein amide bands, indicating the absence of molecular degradation. Statistically significant differences in wheat grains after thermal and sorption drying were observed in luminescence peak intensities and standard deviation of the main spectral band’s half width. The MRI method demonstrated that sorption drying preserves optimal grain tissue microstructure while maintaining proper moisture levels and distribution prior to germination, as well as supporting natural mass transfer processes and moisture distribution evolution during dehydration. Full article

This study undertakes a thorough examination of hydrogen solubility within various metal-alloy membranes, including those based on palladium (Pd), vanadium (V), niobium (Nb), tantalum (Ta), amorphous alloys and liquid gallium (Ga). The analysis aims to outline the strengths and weaknesses of each material in terms of solubility and permeability performance. The investigation began by acknowledging the dual definitions of solubility found in literature: the “secant method”, which calculates solubility based on the hydrogen pressure corresponding to a specific sorbed hydrogen loading, and the “tangent method”, which evaluates solubility as the derivative (differential solubility) of the sorption isotherm at various square root values of hydrogen partial pressure. These distinct methodologies yield notably different outcomes. Subsequently, a compilation of experimental data for each membrane type is gathered, and these data are re-analysed to assess both solubility definitions. This enabled a clearer comparison and a deeper analysis of membrane behaviour across different conditions of temperature, pressure, and composition in terms of hydrogen solubility in the metal matrix. The re-evaluation presented in this study serves to identify the most suitable membranes for hydrogen separation or storage, as well as to pinpoint the threshold of embrittlement resulting from hydrogen accumulation within the metal lattice. Lastly, recent research has indicated that particularly promising membranes are those fashioned as “sandwich” structures using liquid gallium. These membranes demonstrate resistance to embrittlement while exhibiting superior performance characteristics. Full article

The efficiency of membrane reactors for steam reforming of hydrocarbons depends critically on the performance and selectivity of hydrogen-permeable membranes. In this work, a strategy for controlling the catalytic and gas-transport characteristics of Pd-Ag-Ru membranes by modifying the surface and controlling the morphology of nanostructured coatings was developed. It was found that as the process temperatures approached ~200 °C and the membrane thickness decreased, a transition to limitation of the hydrogen transfer process by surface stages was observed. Surface modification with pyramidal nanoparticles resulted in a significant increase in the hydrogen flux by up to 1.5 times compared to membranes with spiked nanoparticles and up to 2 times compared to membranes with spherical nanoparticles. The maximum difference in fluxes of up to 12 times was achieved compared to uncoated membranes. The achieved result is due to a significant increase in the active surface area associated with a systematic change in the morphology of the coatings. This aspect was a key factor in improving the catalytic activity of the material, reducing the energy barrier of sorption and accelerating the stages of hydrogen transfer through the developed membranes. Thus, modification with shape-controlled nanoparticle coatings presents an effective strategy for overcoming the limitations of the permeability of palladium-based membranes under conditions of small thickness and low temperatures. The use of the developed membranes in steam reforming reactors of alcohols can provide increased energy efficiency, conversion and purity of hydrogen. Full article

Rapeseed is a valuable oilseed crop, and efficient drying plays a crucial role in preserving its quality. Because of the high moisture content in rapeseed, drying using the conventional methods may cause it to overheat. The benefit of energy-efficient sorption drying is that it allows one to carefully remove moisture from seeds without using heat, thus ensuring better quality. This study focuses on the characteristics of rapeseed drying using fine crystalline magnesium sulfate MgSO₄·nH₂O as a desiccant. The properties of the desiccant were analyzed using the SEM–EDS, XRD, ATR–MIR, and DSC-TG techniques before and after contacting rapeseed. The findings demonstrate that the desired moisture content of 7–8% can be achieved within 60–240 min, depending on the initial moisture content of rapeseed (ranging from 12% to 16%) and the desiccant-to-rapeseed ratio (1:2, 1:4, or 1:6). An analysis of crystalline hydrates after sorption drying indicates that the desiccant can be reused without intermediate regeneration during multi-stage drying of two to three rapeseed batches. The germination capacity of the seeds after sorption drying was as high as 90%, meeting the standards for elite rapeseed categories. This research demonstrates that sorption drying using magnesium sulfate is an efficient method for reducing moisture content in oilseeds, while maintaining their quality. Full article

Not all produced compost meets established quality standards, often resulting in environmental challenges. This study investigated the potential of using mature compost as a feedstock for biochar production, with a focus on evaluating the gas adsorption properties of the resulting biochars. Mature compost was utilized as a substrate, and the pyrolysis process involved heating samples within a temperature range of 400–650 °C, at 50 °C intervals, with heating rates of 10 °C·min⁻¹, 15 °C·min⁻¹, or 20 °C·min⁻¹ for a duration of 60 min. The resulting biochars were tested for their adsorption performance against a synthetic gas mixture simulating composting emissions (CO₂, CO, H₂S, NH₃, CH₄ in N₂). Our findings reveal a significant correlation between the pyrolysis temperature and the sorption characteristics of compost biochars. Specifically, biochars produced at temperatures of 550 °C, 600 °C, and 650 °C (with a heating rate of 10 °C·min⁻¹) demonstrated the highest efficacy in reducing emissions of CO₂, CH₄, and H₂S, achieving reductions of 69%, 69%, and 72%, respectively. However, these biochars exhibited lower adsorption capacity for CO and NH₃. Interestingly, biochars produced at 400 °C and 450 °C showed enhanced performance for CO adsorption. Compost biochar shows strong potential for gas adsorption, particularly for CO, CO₂, and H₂S. Due to its pronounced CH₄ sorption capacity, such biochar is better suited for mitigating emissions during composting rather than for biogas purification. Full article

The global scarcity of freshwater, driven by population growth and the unequal distribution of water resources, has intensified the need for alternative water supply technologies. Among the most promising solutions, adsorption-based atmospheric water harvesting (AWH) systems offer the ability to extract water vapor directly from ambient air, even under low-humidity conditions. This review presents a comprehensive overview of the thermodynamic principles and material characteristics governing these systems, with particular emphasis on adsorption isotherms and their role in predicting and optimizing system performance. A generalized theoretical framework is proposed to assess the energy efficiency of thermally driven AWH devices, based on key material parameters. Recent developments in sorbent materials, especially metal–organic frameworks (MOFs) and advanced zeolites, are examined for their high-water uptake, regeneration efficiency, and potential for operation under real climatic conditions. The Dubinin–Astakhov and modified Langmuir isotherm models are reviewed for their effectiveness in describing nonlinear sorption behaviors critical to performance modeling. In addition, component-level design strategies for adsorption-based AWH systems are discussed. The integration of solar energy is also discussed, highlighting recent prototypes and design strategies that have achieved water yields ranging from 0.1 to 2.5 L m⁻²/day and specific productivities up to 2.8 L kg⁻¹ using MOF-801 at 20% RH. Despite notable progress, challenges remain, including limited productivity in non-optimized setups, thermal losses, long-term material stability, and scalability. This review concludes by identifying future directions for material development, system integration, and modeling approaches to advance the practical deployment of efficient and scalable AWH technologies. Full article

Molecularly imprinted polymers (MIPs) for silver sorption were synthesized using diethylene glycol dimethacrylate (DEGDMA) and divinylbenzene (DVB) as crosslinking agents. Synthesis was carried out using a ratio template: monomer: monomer: cross-linker = 1:2:2:8. The yield of obtained imprinting structures was 63.2% and 67.8% for MIP(DEGDMA) and MIP(DVB), respectively. The MIPs were analyzed by FTIR analysis, which showed the presence of characteristic peaks indicating the presence of monomers and crosslinkers in the MIP structure. According to the results of SEM analysis, the average cavity size for MIP(DEGDMA) is 0.81 ± 0.20 μm and for MIP(DVB) is 0.68 ± 0.23 μm in diameter. MIP(DEGDMA)’s sorption degree is 66.08%, and its sorption capacity is 3.31 g/g; MIP(DVB)’s sorption degree is 78.35%, and its sorption capacity is 3.92 g/g. The desorption degree is 69.85% for MIP(DEGDMA) and 69.52% for MIP(DVB). For analysis of sorption kinetics, the Radushkevich and Elovich kinetic models were applied. Full article

Hybrid materials based on porous organic polymers (POPs) and metal–organic frameworks (MOFs) are increasing attention for advanced separation processes due to the possibility to combine their properties. POPs provide high surface areas, chemical stability, and tunable porosity, while MOFs contribute a high variety of defined crystalline structures and enhanced separation characteristics. The combination (or hybridization) with PIMs gives rise to mixed-matrix membranes (MMMs) with improved permeability, selectivity, and long-term stability. However, interfacial compatibility remains a key limitation, often addressed through polymer functionalization or controlled dispersion of the MOF phase. MOF/COF hybrids are more used as biochemical sensors with elevated sensitivity, catalytic applications, and wastewater remediation. They are also very well known in the gas sorption and separation field, due to their tunable porosity and high electrical conductivity, which also makes them feasible for energy storage applications. Last but not less important, hybrids with other POPs, such as hyper-crosslinked polymers (HCPs), covalent triazine frameworks (CTFs), or conjugated microporous polymers (CMPs), offer enhanced functionality. MOF/HCP hybrids combine ease of synthesis and chemical robustness with tunable porosity. MOF/CTF hybrids provide superior thermal and chemical stability under harsh conditions, while MOF/CMP hybrids introduce π-conjugation for enhanced conductivity and photocatalytic activity. These and other findings confirm the potential of MOF-POP hybrids as next-generation materials for gas separation and carbon capture applications. Full article

This study reported covalent organic frameworks (COFs) and their hybrid composites with two-dimensional materials, graphene oxide (GO), graphitic carbon nitride (g-C₃N₄), and boron nitride (BN), to examine their structural, textural, and gas adsorption properties. Material characterization confirmed the crystallinity of COF-1 and the preservation of framework integrity after integrating the 2D nanomaterials. FT-IR spectra exhibited pronounced vibrational fingerprints of imine linkages and validated the functional groups from the COF and the integrated nanomaterials. TEM images revealed the integration of the two components, porous, layered structures with indications of interfacial interactions between COF and 2D nanosheets. Nitrogen adsorption–desorption isotherms revealed the microporous characteristics of the COFs, with hysteresis loops evident, indicating the development of supplementary mesopores at the interface between COF-1 and the 2D materials. The BET surface area of pristine COF-1 was maximal at 437 m²/g, accompanied by significant micropore and Langmuir surface areas of 348 and 1290 m²/g, respectively, offering enhanced average pore widths and hierarchical porous strcuture. CO₂ adsorption tests were investigated showing maximum adsorption capacitiy of 1.47 mmol/g, for COF-1, closely followed by COF@BN at 1.40 mmol/g, underscoring the preserved sorption capabilities of these materials. These findings demonstrate the promise of designed COF-based hybrids for gas capture, separation, and environmental remediation applications. Full article

The aim of this work was to obtain biochar materials from plant biomass and to determine the changes occurring under the conditions of the pyrolysis process and physical activation, as well as to characterize the physicochemical characteristics of the produced products in terms of their practical use. The pyrolysis process was carried out at a temperature of 700 °C, under the flow of a protective gas, i.e., carbon dioxide, at a rate of 5.0 L/min. The pyrolysis processes were carried out in the absence and presence of an activating agent. For ecological safety, physical activation using water vapor was chosen. In the next stage of the work, biochars were produced and subjected to detailed physicochemical analysis. A scanning electron microscope with energy-dispersive SEM/EDS was used to determine the microstructure and changes in the chemical composition of the biochars. FTIR spectrophotometry was used to identify the functional groups present in the structures of biochars and to indicate changes occurring in the biomass during pyrolysis. Meanwhile, Raman spectroscopy was used to assess the ordering of the biochar structures based on the identification of spectral signals. The description of the specific surface areas of the biochars was made possible by studies conducted using a physical and chemical adsorption analyzer. Based on the obtained research results, the elementary structure, surface development, presence of functional groups on the surfaces of biochars and changes in the structure before and after activation with water vapor were determined. It was found that the biochars had functional groups, a well-developed specific surface area that increased after activation with water vapor, micropores and mesopores, as well as changes in structure under the influence of physical activation. It has been shown that the presence of functional groups influences the hydrogen sulfide sorption capacity. Full article

Air purification is a key process aimed at removing harmful impurities and providing a safe and comfortable environment for human life and work. This study presents the results of an investigation into the composition, textural, and sorption properties of a multichannel carbon filtering material developed for air purification from biological (infectious) contaminants. The filtering block has a cylindrical shape and is manufactured by extrusion of a plastic composition based on carbonized rice husk with the addition of binding agents, followed by staged thermal treatment (calcination, activation, and demineralization). The filter’s effectiveness is based on the inactivation of pathogenic microorganisms as the air passes through the porous surface of the sorbent, which is modified with broad-spectrum antiseptic agents (active against bacteria, bacilli, fungi, and protozoa). X-ray diffraction analysis revealed the presence of amorphous carbon in a tubostratic structure, with a predominance of sp- and sp²-hybridized carbon atoms not incorporated into regular graphene lattices. IR spectroscopy demonstrated the presence of reactive functional groups characteristic of the developed porous structure of the material, which is capable of selective sorption of antiseptic molecules. SEM surface analysis revealed an amorphous texture with a loose structure and elements in the form of spherical semi-ring formations formed by overlapping carbon plates. An experimental setup was also developed using cylindrical multichannel carbon blocks with a diameter of 48 mm, a length of 120 mm, and 100–120 longitudinal channels with a cross-section of 1 mm². The obtained results confirm the potential of the proposed material for use in air purification and disinfection systems under conditions of elevated biological risk. Full article

Background/Objectives: Airborne viral diseases pose a health risk, due to which there is a growing interest in developing filter materials capable of capturing fine particles containing virions from the air and that also have a virucidal effect. Nanofiber membranes made of poly(vinylidene fluoride) dissolved in N,N-dimethylacetamide and functionalized with copper, silver, and zinc nanoclusters were fabricated via electrospinning. This study aims to evaluate and compare the virucidal effects of nanofibers functionalized with metal nanoclusters against the human influenza A virus A/WSN/1933 (H1N1) and SARS-CoV-2. Methods: A comprehensive characterization of materials, including X-ray diffraction, scanning electron microscopy, microwave plasma atomic emission spectroscopy, thermogravimetric analysis, contact angle measurements, nitrogen sorption analysis, mercury intrusion porosimetry, filtration efficiency, and virucidal tests, was used to understand the interdependence of the materials’ physical characteristics and biological effects, as well as to determine their suitability for application as antiviral materials in air filtration systems. Results: All the filter materials tested demonstrated very high particle filtration efficiency (≥98.0%). The material embedded with copper nanoclusters showed strong virucidal efficacy against the SARS-CoV-2 alpha variant, achieving an approximately 1000-fold reduction in infectious virions within 12 h. The fibrous nanowire polymer functionalized with zinc nanoclusters was the most effective material against the human influenza A virus strain A/WSN/1933 (H1N1). Conclusions: The materials with Cu nanoclusters can be used with high efficiency to passivate and kill the SARS-CoV-2 alpha variant virions, and Zn nanoclusters modified activated porous membranes for killing human influenza A virus A7WSN/1933 (H1N1) virions. Full article

Heat treatment is a widely employed method for modifying solid wood and has also been extended to veneer-type woods. Owing to the thinness and ease of handling of veneers, the regulation of protective media in heat treatment has not been highly regarded by the industry and is scarcely reported in research. In light of this, in this paper, rubber wood (Hevea brasiliensis) veneer is taken as the research subject to investigate the influences of heat treatment with hot air (HTHA) and heat treatment with superheated steam (HTSS) at different temperatures on the chemical properties, longitudinal tensile strength, color values, hygroscopicity, thermal degradation performance and microstructure of the wood. The results show that heat treatment alters the chemical properties of wood. Both heat treatments reduce the content of hemicellulose and other components in the veneer, and the characteristic peak of lignin in HTSS is slightly enhanced. The crystallinity of the veneer slightly increases after heat treatment, and the increase in HTSS is greater than that in HTHA. Through scanning electron microscopy, it is observed that heat treatment can effectively remove starch granules in rubber wood veneer, with HTSS being superior to HTHA, and the removal effect increases with the rise in temperature. The longitudinal tensile strength of the veneer decreased by 0.69%, 3.87%, and 24.98% respectively at 135~155 °C HTHA, and by 3.25%, 7.00%, and 18.47% respectively at 135~155 °C HTSS. Both heat treatments reduced the lightness of the veneer and increased the chroma index. At 155 °C, the color difference value of the veneer treated by HTSS was smaller than that treated by HTHA. The effects of heat treatment on the moisture absorption performance of the veneer were different. The equilibrium moisture content of the veneer treated at 135 °C HTHA and 135~155 °C HTSS was lower than that of the untreated material, indicating an improvement in moisture absorption stability. The maximum moisture sorption hysteresis of untreated material is 3.39%. The maximum moisture sorption hysteresis of 135 °C HTHA is not much different from that of untreated material. The values of 145 °C and 155 °C HTHA increase by 8.85% and 9.14% respectively. The values of 135 °C, 145 °C, and 155 °C HTSS increase by 22.42%, 25.37%, and 19.47% respectively. The moisture absorption hysteresis of the veneer increases after heat treatment, and the effect of HTSS improvement is more significant. From the TG and DTG curves, it can be seen that the residual mass percentage of the veneer after heat treatment is higher than that of the untreated material. The residual mass percentage of HTHA at 135 °C, 145 °C, and 155 °C increased by 3.13%, 3.07%, and 2.06% respectively, and that of HTSS increased by 5.14%, 7.21%, and 6.08% respectively. Full article