Articles
Journal of Membrane Science (18733123)713
This study investigates the effects of various porous supports and the presence of additional gases in the feed on hydrogen permeation using an unsupported Pd82–Ag15–Y3 membrane. The pore sizes and thicknesses of metallic supports varied from 1 to 270 μm and 50–3000 μm, respectively. The membrane was unsupported, synthesized by cold-rolling, and characterized by a thickness of 38 μm. The tests were performed at 400 °C with pressures ranging from 1.4 to 3 bar. Results showed that the unsupported Pd82–Ag15–Y3 membrane reached 12 % and 267 % higher hydrogen permeation than the supported membrane by 1 μm pore size and 50 μm thick woven mesh, and 1 μm pore size and 3 mm thick of porous stainless steel (PSS), respectively. The unsupported Pd82–Ag15–Y3 membrane showed one of the highest hydrogen permeability in the literature (7.5 × 10−8 mol m−1 s−1.Pa−0.5 at 400 °C). However, the presence of porous supports used to enhance the mechanical stability of the membrane negatively affected the hydrogen permeation due to mass transfer limitation. In addition, the presence of supports induced an unreal ‘n’ value for the Pd-based membrane, where the ‘n’ value is the exponent of the driving force in the equation of hydrogen transport, varying between 0.5 and 1. In particular, for the unsupported membrane, the ‘n’ value was 0.6, but it increased to 0.7 and 0.8 when supports with 1 μm pore size and 50 μm thick and 5 μm and 80 μm thick were utilized. Binary hydrogen permeation tests were also performed in the presence of N2, CH4, CO2, and CO at 400 °C by using unsupported and supported membranes to investigate the reduction in hydrogen permeation flux due to the effect of the supports plus the effect of the presence of other gas. The results revealed that CO had the highest inhibition effect for all the unsupported and supported membranes tested due to competitive adsorption on the surface. No superficial adsorption on the membrane was observed for N2, CH4, and CO2 during permeation, and they inhibited hydrogen permeation mainly due to depletion, dilution, and concentration polarization. The PSS_1–3000 indicated the lowest hydrogen permeation between the gas mixture and the porous support, whereas the presence of 40 % of the binary gas mixture had lower hydrogen permeation than porous support except for the PSS. © 2024 Elsevier B.V.
Colloids and Surfaces A: Physicochemical and Engineering Aspects (18734359)725
The development of epoxy adhesives with superior adhesion properties has long been a critical requirement in the high-tech applications. In this study, two metal organic frameworks (MOFs), MIL-101(Cr) (MIL, Matérial Institut Lavoisier) and NH2-MIL-101(Cr), were used to enhance the adhesion characteristics. These MOFs, were characterized by different analytical techniques, and subsequently integrated into high-temperature epoxy adhesives to improve their mechanical and thermal properties as well as adhesion strength. Notably, the addition of 0.3 parts per hundred resin (phr) of MIL-101(Cr) to the epoxy matrix resulted in an impressive ∼100 % increase in tensile strength and a remarkable 24 % enhancement in lap shear strength. Furthermore, the incorporation of the amine-functionalized NH2-MIL-101(Cr) into the epoxy matrix led to even more significant improvements in mechanical strength. The addition of just 0.3 phr of NH2-MIL-101(Cr) gave rise in a striking ∼150 % increment in tensile strength compared to the pristine epoxy adhesives, while lap shear strength experienced a substantial 50 % growth. The thermal stability of the epoxy adhesive was notably enhanced in the presence of the MOFs. Differential scanning calorimetry (DSC) analysis indicated an increase in the curing enthalpy upon the incorporation of both MIL-101(Cr) and NH2-MIL-101(Cr) into the epoxy matrices. The use of amine-functionalized MOFs significantly improved the thermal and mechanical properties of the epoxy adhesives, paving the way for the development of innovative epoxy formulations. © 2025
Kaveh, A.,
Moini jazani, O.,
Asghari, S.,
Mirmohammadi, S.M.,
Ghaderi, H.,
Taghavi, M.R. Journal of Reinforced Plastics and Composites (07316844)
The enhancement of epoxy composites has emerged as a captivating area of research in recent years, particularly in addressing the critical challenge of filler debonding within the epoxy matrix. This study explores the use of chemically oxidized carbon fibers (CFs) as a reinforcing agent to significantly improve the thermal and mechanical properties of epoxy composites. The oxidation process increases the surface functional groups on CFs, facilitating better interaction during curing. Our findings reveal a remarkable 32% increase in tensile strength and a 28% increase in modulus strength when comparing molded composites of pristine and oxidized CFs. Furthermore, interlaminar shear strength analysis demonstrates a striking 92% improvement in adhesion properties, rising from 30.4 MPa for pristine CFs to 58.3 MPa for oxidized CFs. Thermal gravimetric analysis indicates a substantial enhancement in thermal stability for the epoxy/oxidized CFs composite. Notably, the fracture mode transitions from adhesive failure in pristine CFs to cohesive failure in the oxidized variants. This paper presents a straightforward and effective strategy for modifying CFs, paving the way for the development of advanced composites with superior thermal and mechanical properties. © The Author(s) 2025
BioNanoScience (21911630)15(1)
Carbon dots (CDs) are nanoparticles (NPs) used in cancer treatment for medical imaging and drug delivery. This research examines the characteristics of carbon quantum dots (CQDs) that make them suitable for medical purposes. CQDs, consisting of carbon atoms with unique properties, are less than 10 nm in size and possess biocompatibility and energy release capabilities. Recent advancements in utilizing CQDs for bioimaging and therapy, including light-based treatments and antibacterial therapies, are discussed. The study also emphasizes the importance of monitoring, self-transformation, and future advancements in biological applications to obtain regulatory approval for clinical use, such as from the FDA. The research provides a detailed analysis of CQDs’ biomedical applications, highlighting their dispersibility, compatibility, and photoluminescent properties for applications such as drug delivery, biosensing, and controlled release. Various synthetic methods for different types of CQDs, including modified versions, are explored, along with investigations into pharmacokinetics, toxicity profiles, and implications in clinical and biological settings. Overall, this study offers a comprehensive understanding of CQDs’ synthesis, modification, pharmacokinetics, toxicity, polymer composite, and future research directions for bioimaging applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
