Combining theoretical and experimental approaches is a strong and synergic strategy for further increasing the knowledge of materials. We report a combined experimental and theoretical study of a copper squarate MOF (Cu-SQ-1) synthesized via a highly sustainable route in aqueous medium at room temperature, without additives, deprotonating agents, or external energy input. The hydrated material is initially non-porous (SBET = 11 m2 g−1), but upon mild thermal treatment (≈150 °C) it undergoes a structural transition that generates a stable microporous crystalline phase within a narrow thermal window prior to decomposition. The activated material exhibits a micropore surface area around 197 m2 g−1 (SBET = 257 m2 g−1) and a pore volume of 0.16 cm3 g−1, confirming the activation of intrinsic porosity. DFT, DFPT, and Grand Canonical Monte Carlo (GCMC) simulations are consistent with the experimental results, reproducing the crystal structures, vibrational spectra (IR and Raman), and gas adsorption isotherms. In gas adsorption studies, Cu-SQ-1 shows a hydrogen uptake of 1.0 wt% at 77 K and 1 bar, reaching 1.86 wt% at 20 bar, with experimental adsorption enthalpies of ∼7 kJ mol−1 (theoretical: 8.27 kJ mol−1) and local interaction energies up to 23 kJ mol−1. For CO2, a capacity of 2.35 mmol g−1 is obtained at 273 K and 1 bar, significantly higher than for N2, indicating selectivity toward gases with higher quadrupole moments. The good correlation between experimental and theoretical results validates the proposed structural model and confirms Cu-SQ-1 as a sustainable squarate MOF with strong affinity for light gases and promising potential for selective CO2 capture and hydrogen storage.
The increasing release of rare earth elements (REEs) in aquatic ecosystems, resulting from their expanding use in emerging technologies, has raised environmental concerns and highlights the need for effective and selective adsorbents. To the best of our knowledge, this study represents the first systematic comparison of the influence of porphyrinoid macrocycle size and core structure on REE uptake by silica-supported hybrid materials, providing insights into structure–property relationships governing adsorption behavior. Four hybrid materials, SiCor, SiPor, SiPen, and SiHex, were synthesized by grafting corrole, porphyrin, pentaphyrin, and hexaphyrin macrocycles, respectively, onto an aminopropyl-functionalized silica surface hereafter referred to as SiPn. UV–Vis spectroscopy, FTIR, and BET analyses supported successful functionalization and revealed the structural/textural differences among the hybrids. Batch sorption experiments were performed at pH 6 using ultrapure water spiked with a mixed-REE solution (La, Ce, Nd, Eu, Gd and Dy; 1 μmol L−1 each) and two sorbent doses (50 and 500 mg L−1) for up to 48 h. Reference experiments with pristine silica (Si) and aminopropyl-functionalized silica (SiPn) revealed measurable REE uptake by the support itself, particularly at the higher sorbent dose. Under identical conditions, SiPor and SiPen showed limited REE removal, whereas SiHex displayed moderate uptake at 500 mg L−1 (e.g., up to 53 % for Dy). SiCor showed the highest performance at 500 mg L−1, achieving more than 90 % removal for Ce, Nd, Eu, Gd and Dy and approximately 80 % for La after 48 h, with most elements reaching high removal within 24 h. The results reveal a strong dependence of REE removal on porphyrinoid core structure and demonstrate that, although the silica support contributes to REE uptake, adsorption performance within this series is strongly influenced by the identity and electronic characteristics of the macrocyclic ligand. Among the materials investigated, corrole-functionalized silica emerges as the most promising platform for the rational design of macrocycle-based adsorbents for REE removal from water and provides a foundation for the development of optimized corrole-based sorbents for trace-level REE uptake.
Mesoporous silica nanoparticles (MSN) are widely used as drug delivery systems but the efficient loading of hydrophilic compound is still challenging. Fluorescein (FS) was chosen as a model hydrophilic compound in order to evaluate its loading ability into MSN. The MSN were synthesized using the modified Stöber method and loaded with fluorescein using an innovative co-spray drying process. The unloaded and loaded MSN were then characterized by various multiscale physico-chemical techniques to determine the morphology, composition and pore filling of the particles, as well as the conformation of the loaded particles after spray-drying. This extensive characterization provides a detailed understanding of the loading mechanism and the organization of the loaded compounds inside the porous matrix. The effect of FS/MSN mass ratio on the loading capacity was evaluated and the performance was compared to previous results on the loading of a hydrophobic compound, ibuprofen, performed with the same co-spray drying process. It was found that the loading content with the hydrophilic substance was lower for the same agent-to-carrier ratio. The hydrophilic or hydrophobic nature of the loaded compound, and consequently its interactions with the mesoporous silica surface, is a determining factor governing the loading capacity of the particles, even when the loading is performed by co-spray drying, where the forces governing the loading are, however, different from those in a conventional impregnation process.
Natural zeolites are attractive microporous materials owing to their structural stability, ion-exchange capability, and versatile surface chemistry. In this study, Zn, Fe, and Cu species were sequentially incorporated into natural clinoptilolite through a combined ion-exchange and chemical reduction strategy to obtain a multifunctional metal-modified zeolite. The structural evolution and antibacterial properties of the resulting material were systematically investigated using FTIR, XRD, SEM, and microbiological assays against Escherichia coli and Pasteurella multocida. FTIR and XRD analyses demonstrated that multi-metal incorporation preserved the characteristic aluminosilicate framework and crystalline structure of clinoptilolite while enabling the formation of metal-containing phases. SEM observations revealed homogeneous dispersion of nanoparticles on the zeolite surface with substantially reduced agglomeration compared with the unsupported metallic composite. The modified clinoptilolite exhibited enhanced antibacterial activity against E. coli, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.3 and 625 μg mL−1, respectively, corresponding to approximately two-fold greater activity than the unsupported counterpart. In contrast, pristine clinoptilolite showed no detectable antibacterial effect. Disk diffusion assays further confirmed the superior antibacterial performance of the tri-metallic system. The enhanced activity is attributed to the synergistic effects of Zn, Fe, and Cu species together with the ability of the clinoptilolite framework to promote nanoparticle dispersion, suppress aggregation, and increase accessibility of active sites. These findings demonstrate that sequential ion exchange is an effective route for engineering multifunctional metal-modified clinoptilolite while preserving the structural integrity of the zeolitic framework.
This study investigates the growth characteristics of chrysotile synthesized from a coprecipitated precursor under hydrothermal conditions at 200 °C within 6 – 672 h. Using a combination of complementary analytical techniques – including powder X-ray diffraction, low-temperature nitrogen adsorption, dynamic light scattering, and ζ-potential measurements – we established that the formation process proceeds via several distinct stages: the generation of poorly crystallized curved plate-like particles, their partial recrystallization into prototubulens, and the subsequent nucleation and active growth of nanoscrolls, followed by their progressive structural refinement. The onset of massive nanoscroll formation occurs at 24 h of hydrothermal treatment, whereas after 96 h, scroll growth predominates. For the first time, this synthesis route is accompanied by a detailed characterization of the evolution of unit-cell parameters, interplanar spacing, porous structure, and particle morphology (inner and outer diameters, and length). The obtained data were validated by transmission electron microscopy, confirming the reliability of these analytical approaches for determining the dimensional parameters of phyllosilicate particles.
