This study effectively demonstrates the importance of high-molecular-weight TiO2 and PEG additives in significantly improving the overall performance of PSf MMMs.
Membranes of nanofibrous hydrogel structure possess high specific surface areas and are well-suited for use as drug delivery systems. Continuous electrospinning creates multilayer membranes, expanding the diffusion paths, thus delaying drug release, a beneficial feature for prolonged wound management. A layered membrane structure of PVA/gelatin/PVA was created by electrospinning, utilizing PVA and gelatin as membrane substrates while manipulating both the drug concentration and the duration of the electrospinning process. Employing citric-acid-crosslinked PVA membranes loaded with gentamicin as the exterior layers and a curcumin-loaded gelatin membrane in the middle layer, this study investigated the release characteristics, antibacterial activity, and biocompatibility. In vitro release assays showed the multilayer membrane releasing curcumin more slowly, with a 55% lower amount compared to the single-layer membrane within four days. Immersion of the majority of prepared membranes resulted in no discernible degradation, while the phosphonate-buffered saline absorption rate of the multilayer membrane was approximately five to six times its mass. The gentamicin-integrated multilayer membrane effectively inhibited Staphylococcus aureus and Escherichia coli, as determined by the antibacterial test. The layer-by-layer assembled membrane demonstrated non-cytotoxicity but negatively affected cell adhesion, regardless of the gentamicin concentration used. Applying this feature as a wound dressing during dressing changes can help reduce the risk of secondary wound damage. Employing this multilayer wound dressing in future wound care could potentially decrease the risk of bacterial infections and encourage healing.
This research focuses on the cytotoxic effects of novel conjugates—ursolic, oleanolic, maslinic, and corosolic acids conjugated with the penetrating cation F16—on cancer cells (lung adenocarcinoma A549 and H1299, breast cancer cell lines MCF-7 and BT474) and human non-tumor fibroblasts. The results unequivocally show that conjugated compounds display a considerably higher toxicity towards tumor-derived cells than their corresponding native acid forms, while also exhibiting selectivity against certain cancerous cell types. Cells exposed to conjugates exhibit an increased generation of reactive oxygen species (ROS), a consequence of the conjugates' effect on mitochondrial function, resulting in toxicity. Isolated rat liver mitochondria exhibited dysfunctional responses to the conjugates, including reduced oxidative phosphorylation, diminished membrane potential, and elevated ROS production. biocontrol agent The paper investigates if the observed toxicity of the conjugates is related to their dual effect on membranes and mitochondria.
Concentrating the sodium chloride (NaCl) from seawater reverse osmosis (SWRO) brine for direct chlor-alkali industry use is proposed in this paper, with monovalent selective electrodialysis as the method. To achieve heightened monovalent ion selectivity, a selective polyamide layer was created on commercial ion exchange membranes (IEMs) employing the interfacial polymerization of piperazine (PIP) and 13,5-Benzenetricarbonyl chloride (TMC). With a range of techniques, the impact of IP modification on the chemical structure, morphology, and surface charge of the IEMs was investigated. Ion chromatography (IC) analysis quantified the divalent rejection rate for IP-modified IEMs at more than 90%, representing a considerable improvement over the divalent rejection rate of less than 65% for commercial IEMs. Analysis of electrodialysis results revealed a successful concentration of the SWRO brine to 149 grams of NaCl per liter, requiring a power consumption of 3041 kilowatt-hours per kilogram. This highlights the effectiveness of the IP-modified ion exchange membranes. IP-modified IEMs, incorporated into a monovalent selective electrodialysis technology, potentially offer a sustainable means of directly employing sodium chloride in the chlor-alkali manufacturing process.
The organic pollutant aniline is highly toxic, demonstrating carcinogenic, teratogenic, and mutagenic characteristics. This paper proposes a membrane distillation and crystallization (MDCr) process to accomplish zero liquid discharge (ZLD) of aniline wastewater streams. learn more During the membrane distillation (MD) process, hydrophobic PVDF membranes served as the separation medium. A comprehensive analysis was performed on the effects of feed solution temperature and flow rate on MD performance. The outcomes of the study indicated that the flux of the membrane distillation process attained a peak of 20 Lm⁻²h⁻¹, coupled with salt rejection exceeding 99%, under a feed temperature of 60°C and a flow rate of 500 mL/min. Pretreatment with Fenton oxidation, in aniline wastewater, was examined to determine its impact on aniline removal efficiency. The possibility of zero liquid discharge (ZLD) for aniline wastewater within the MDCr process was likewise verified.
Membrane filters were produced by utilizing a CO2-assisted polymer compression method, using polyethylene terephthalate nonwoven fabrics exhibiting an average fiber diameter of 8 micrometers. To evaluate the tortuosity, pore size distribution, and percentage of open pores, the filters were first subjected to a liquid permeability test, and subsequently an X-ray computed tomography structural analysis was performed. The porosity was proposed as a variable governing the tortuosity filter, as indicated by the results. There was a notable concordance between pore size estimations from permeability tests and those from X-ray computed tomography. A porosity of 0.21 still exhibited a ratio of open pores to all pores of as much as 985%. The depletion of trapped high-pressure CO2 following the molding process might account for this. In filter applications, the effectiveness is heightened by a high open-pore ratio, which ensures a large number of pores participate in fluid conveyance. A CO2-assisted polymer compression technique was deemed appropriate for the fabrication of porous filter media.
Successful operation of proton exchange membrane fuel cells (PEMFCs) is fundamentally linked to the effective management of water within the gas diffusion layer (GDL). Efficient water management facilitates the transport of reactive gases, ensuring the proton exchange membrane remains consistently wet for optimal proton conduction. To examine liquid water movement within the GDL, a two-dimensional pseudo-potential multiphase lattice Boltzmann model is developed in this paper. We investigate the flow of liquid water from the gas diffusion layer towards the gas channel, specifically evaluating the consequences of fiber anisotropy and compression on the water management. The results reveal a decrease in liquid water saturation levels within the GDL, as the fiber orientation is approximately perpendicular to the rib. Substantial changes to the GDL's microstructure, especially beneath the ribs, are observed under compression, enabling the development of liquid water transport routes beneath the gas channel; a higher compression ratio correlates with a lower liquid water saturation. The microstructure analysis and pore-scale two-phase behavior simulation study offer a promising approach to optimizing liquid water transport in the GDL.
An experimental and theoretical investigation of carbon dioxide capture using a dense hollow fiber membrane is presented in this work. To investigate the factors affecting carbon dioxide flux and recovery, a lab-scale system was employed. To model natural gas, experiments employed a mixture of methane and carbon dioxide. The influence of CO2 concentration (2-10 mol%), feed pressure (25-75 bar), and feed temperature (20-40 degrees Celsius) on the system was examined. The solution diffusion mechanism, integrated with the dual sorption model, allowed for the development of a comprehensive model predicting CO2 flux through the membrane, calculated using the series resistance model. A 2D axisymmetric model of a multilayer HFM was subsequently developed to represent the diffusion of carbon dioxide in the membrane, both radially and axially. The COMSOL 56 CFD method was applied to solve the momentum and mass transfer equations spanning three distinct fiber domains. HPV infection The modeling results were verified through 27 experimental runs, highlighting a positive relationship between the simulation outcomes and the empirical data. The experimental findings illustrate how operational factors, specifically temperature's influence on gas diffusivity and mass transfer coefficient, manifest. The pressure's effect was diametrically opposed; the carbon dioxide concentration had practically no effect on the diffusivity or mass transfer coefficient. The CO2 recovery rate exhibited a significant shift, increasing from 9% at a pressure of 25 bar, a temperature of 20 degrees Celsius, and a CO2 concentration of 2 mol% to an impressive 303% at an elevated pressure of 75 bar, a temperature of 30 degrees Celsius, and a concentration of 10 mol% CO2; these circumstances constitute the optimal operational parameters. Pressure and CO2 concentration emerged from the results as the operational factors that directly influenced the flux, with temperature having no clear effect in this regard. A gas separation unit's operation, a helpful industrial unit, provides valuable data for feasibility studies and economic evaluations through this modeling.
Wastewater treatment often utilizes membrane dialysis, a type of membrane contactor. The dialysis rate of a traditional dialyzer module is limited because solute movement is restricted to diffusion, with the concentration difference between the retentate and dialysate solutions serving as the driving force for mass transfer. A theoretical mathematical model, two-dimensional, of the concentric tubular dialysis-and-ultrafiltration module was developed for this study.