Preparation and characterization of PVA thin-film composite membrane for pervaporation dehydration of ethanol solution

These days, ethanol fuel has been widely consumed worldwide to replace gasoline due to its possible environmental and long-term economic advantages. In detail, the ethanol fuel (purity ≥ 99.5 wt%) has been produced by traditional separation processes such as azeotropic distillation or molecular sieve adsorption, which excessively employs energy and capital cost. The pervaporation has already been considered as an effective alternative to conventional methods because of its high separation efficiency and low power consumption. Pervaporation separation of ethanol/water solution using hydrophilic membranes has been extensively studied owing to their superior perm-selectivity. In this present work, the polyvinyl alcohol thin-film composite membrane is prepared by casting a thin crosslinked polyvinyl alcohol (PVA) film on the polyacrylonitrile (PAN) porous substrate. The effect of PVA concentration on the pervaporation performance of the fabricated membrane is studied. The physicochemical properties of the prepared membrane are characterized using FTIR, SEM images, and contact angle measurements. The separation performance in terms of permeation flux and selectivity is simultaneously evaluated through a pervaporation dehydration of ethanol/water mixture of 80/20 wt.% at 60°C. The results show that the increase in PVA concentration leads to the decline in the hydrophilicity and the growth of the thickness and swelling degree of the membrane. Therefore, the selectivity of the membrane is found to improve significantly, while the permeation flux decreased with the PVA concentration ranging from 2.5 to 15 wt.%. Based on the results, the PVA membrane prepared from the 10 wt.% concentration is likely to provide high separation performance.

Effect of Curing Temperature on the Properties of Latex Based Membrane for Oily Wastewater Filtration

Oily wastewater pollution has always been part of the most serious worldwide environmental disaster. Thus, the treatment of oily wastewater is notably crucial. In this work, nitrile butadiene rubber/graphene oxide (NBR/GO) membranes were fabricated by latex compounding and curing method which is comparatively brand-new technique to produce membranes for wastewater treatment. Therefore, the steps in the production need to be studied to enhance the performance of the membrane. Curing temperature is an important factor in the production of the latex-based membrane. In this paper, the effect of curing temperature in the range of 90 °C – 110 °C on the morphology, tensile properties, permeation flux, and oil rejection rate performance of the membrane was studied. The curing temperature was found to affect the surface morphology and integrity of the membranes which sequentially affects the performance of the membrane in terms of strength, permeation flux, and oil rejection rate. NBR/GO membranes cured at the temperature of 100 °C exhibit the highest flux of 491.84 L/m2.hr with an oil rejection rate of 95.44 %, with the ultimate tensile strength (UTS), elongation break (EB%), and E-Modulus (E-mod) of 34.490 MPa, 1627.11 %, and 1.309 MPa, respectively.

Fabricating tritium permeation barrier for PFC with a new non-coating strategy

Tritium (T) permeation through plasma-facing component (PFC) into the coolant is a major concern of fusion reactor operation. In this work, deuterium (D) permeation through CLAM steel, CLAM/CLAM and CLAM/Fe-Cr-Al samples prepared by hot isostatic pressing (HIP) are tested in a linear plasma device. Only the downstream surfaces of the samples are oxidized with controlled atmosphere to form permeation barrier. No significant effect on D diffusion and penetration can be observed for the joining interfaces, while the dense oxide layer at the downstream side plays an important role in suppressing D permeation. The downstream surface oxidization of CLAM/Fe-Cr-Al is found to effectively reduce D permeation flux by a factor up to 1000.

Effects of Bi Substitution on the Cobalt-Free 60wt.%Ce0.9Pr0.1O2−δ-40wt.%Pr0.6Sr0.4Fe1−xBixO3−δ Oxygen Transport Membranes

The mixed ionic-electronic conducting (MIEC) oxygen transport membrane (OTM) can completely selectively penetrate oxygen theoretically and can be widely used in gas separation and oxygen-enriched combustion industries. In this paper, dual-phase MIEC OTMs doped with Bi are successfully prepared by a sol-gel method with high-temperature sintering, whose chemical formulas are 60wt.%Ce0.9Pr0.1O2−δ-40wt.%Pr0.6Sr0.4Fe1−xBixO3−δ (60CPO-40PSF1−xBxO, x = 0.01, 0.025, 0.05, 0.10, 0.15, 0.20). The dual-phase structure, element content, surface morphology, oxygen permeability, and stability are studied by XRD, EDXS, SEM, and self-built devices, respectively. The optimal Bi-doped component is 60wt.%Ce0.9Pr0.1O2−δ-40wt.%Pr0.6Sr0.4Fe0.99Bi0.01O3−δ, which can maintain 0.71 and 0.62 mL·min−1·cm−2 over 50 h under He and CO2 atmospheres, respectively. The oxygen permeation flux through these Bi-doped OTMs under air/CO2 gradient is 12.7% less than that under air/He gradient, which indicates that the Bi-doped OTMs have comparable oxygen permeability and excellent CO2 tolerance.

Pure oxygen separation from air using dual-phase SDC-SCFZ disc membrane: A modelling approach

Novel Ce0.8Sm0.2O1.9-SrCo0.4Fe0.55Zr0.05O3-δ (SDC-SCFZ) disc membranes consist of 25 wt.% SDC fluorite ionic conducting phase and 75 wt.% SCFZ perovskite mixed conducting phase, which is more promising than perovskite oxide SCFZ single-phase membrane in terms of the oxygen permeation flux. This work features a modelling approach to simulate the oxygen permeation fluxes of the SDC-SCFZ membrane. Simplified model equations from the Zhu model and Xu-Thomson model based on the limiting cases of surface exchange reactions and bulk diffusion are compared. The Zhu model is found to be more applicable for the membranes with overall good correlation and low sum of squared error. Furthermore, modelling studies revealed that the oxygen transport is limited by surface exchange reactions from 700 to 850 °C and a mixture of both limiting cases above 850 up to 950 °C. It is concluded that the membranes exhibit high oxygen permeation flux of up to 2×10−6 mol s−1 cm−2 at 950 °C with Pair of 5 atm and Po 2 of 0.005 atm. The optimum range of operating conditions of the membrane are found to be at 950 °C with minimum Pair of 1 atm and P11 2 lower than 0.025 atm.

Development and Characterization of Biocompatible Membranes from Natural Chitosan and Gelatin for Pervaporative Separation of Water–Isopropanol Mixture

Natural polymers have attracted a lot of interest in researchers of late as they are environmentally friendly, biocompatible, and possess excellent characters. Membranes forming natural polymers have provided a whole new dimension to the separation technology. In this work, chitosan-gelatin blend membranes were fabricated using chitosan as the base and varying the amount of gelatin. Transport, mechanical, and surface characteristics of the fabricated membranes were examined in detail by means of the characterizing techniques such as Fourier transform infrared spectroscopy, differential scanning colorimetry, wide angle X-ray diffraction, scanning electron microscope, and thermogravimetric analysis. In order to analyze the water affinity of the developed blend chitosan-gelatin membranes, the percentage degree of swelling was examined. Out of the fabricated membranes, the membrane loaded with 15 mass% of gelatin exhibited the better pervaporation performance with a pervaporation separation index value of 266 at 30 °C for the solution containing 10% in terms of the mass of water, which is the highest among the contemporary membranes. All the fabricated membranes were stable during the pervaporation experiments, and permeation flux of water for the fabricated membranes was dominant in the overall total permeation flux, signifying that the developed membranes could be chosen for efficient separation of water–isopropanol mixture on a larger scale.

Development of Methanol Permselective FAU-Type Zeolite Membranes and Their Permeation and Separation Performances

The separation of non-aqueous mixtures is important for chemical production, and zeolite membranes have great potential for energy-efficient separation. In this study, the influence of the framework structure and composition of zeolites on the permeation and separation performance of methanol through zeolite membranes were investigated to develop a methanol permselective zeolite membrane. As a result, the FAU-type zeolite membrane prepared using a solution with a composition of 10 SiO2:1 Al2O3:17 Na2O:1000 H2O showed the highest permeation flux of 86,600 μmol m−2 s−1 and a separation factor of 6020 for a 10 wt% methanol/methyl hexanoate mixture at 353 K. The membrane showed a molecular sieving effect, reducing the single permeation flux of alcohol with molecular size for single-component alcohols. Moreover, the permeation flux of methanol and the separation factor increased with an increase in the carbon number of the alcohols and methyl esters containing 10 wt% methanol. In this study, the permeation behavior of FAU-type zeolite membranes was also discussed based on permeation data. These results suggest that the FAU-type zeolite membrane has the potential to separate organic solvent mixtures, such as solvent recycling and membrane reactors.

Experimental Design Based Optimization and Ex Vivo Permeation of Desmopressin Acetate Loaded Elastic Liposomes Using Rat Skin

The study aimed to develop elastic-liposome-based transdermal delivery of desmopressin acetate for enhanced permeation to control enuresis, central diabetes insipidus, and traumatic injury. Elastic liposomes (ELs)-loaded desmopressin acetate was prepared, optimized, and evaluated for improved transdermal permeation profiles using rat skin. Full factorial design with independent factors (X1 for lipid and X2 for surfactant) at three levels was used against four responses (Y1, Y2, Y3, and Y4) (dependent variables). Formulations were characterized for vesicle size, polydispersity index (PDI), zeta potential, % entrapment efficiency (% EE), in vitro drug release, in vitro hemolysis potential, ex vivo drug permeation and drug deposition (DD), and ex vivo vesicle–skin interaction using scanning electron microscopy studies. The optimized formulation ODEL1 based on desirability function was found to have vesicle size, % EE, % DR, and permeation flux values of 118.7 nm, 78.9%, 75.1%, and 5.3 µg/h·cm2, respectively, which were close to predicted values. In vitro release profiles indicated slow and sustained delivery. Permeation flux values of ODEL1 and ODEL2 were 5.3 and 3.1 µg/h·cm2, respectively, which are 7.5- and 4.4-fold higher as compared to DS (0.71 µg/h·cm2). The obtained flux was relatively higher than the clinical target value of the drug for therapeutic efficacy. Moreover, the DD value of ODEL1 was significantly higher than ODEL2 and DS. Hemocompatibility study confirmed safety concerns. Finally, vesicle–skin interaction corroborated mechanistic views of permeation through rat skin. Conclusively, the transdermal delivery may be a suitable alternative to oral and nasal delivery to treat nocturnal enuresis, central diabetes insipidus, hemophilia A and von Willebrand’s disease, and any traumatic injuries.