Polymer Membrane Systems Research Articles

Predictive modeling of pH on the transport of Co(II) Ions from aqueous solutions through supported ceramic polymer membrane

Optimal pH is essential for efficient cobalt extraction from polymeric membrane systems, with D2EHPA used as an extractant for Co(II) at pH < 7, achieving 47% efficiency. The pH of piperazine as a stripping agent increases to a concentration of 0.48 M, and the extraction efficiency of Co(II) > 80%. Depending on the functional group of (C4H10N2), the optimal pH for separation was 9.8. The study revealed that pKa value was calculated to predict the ideal pH, and its value was 9.73, which is nearly to the pH, since the pH of the strip concentration and the properties of the membrane affect the extraction of cobalt at 30 °C. The partition ratio indicates the high distribution of the extract in supported ceramic polymer membrane (SCPM). The ceramic component provides mechanical strength and rigidity to the overall membrane structure, allowing it to withstand high pressures and temperatures during operation Study various factors such as the effect of pH on the ionization of the extract; effect of pH on band ionization; effect of pH on the temperature in the extract, effect of pH on the solute, effect of the band at different pH ranges and a comparison was made between the predictive model and experimental data that was proven through mathematical modeling using the MATLAB program.

Removal of Simazine from Aqueous Environment through Polymeric Membrane System

Removal of Simazine from Aqueous Environment through Polymeric Membrane System

Separation of acetochlor through polymeric membrane system

In this study, an acetochlor belonging to the herbicide group was transported using a synthesized polymer inclusion membrane (PIM). Tricapryl-methylammonium chloride (Aliquat 366) and cellulose triacetate (CTA) were used as carrier and support material, respectively, in the membrane structure. The acetochlor samples taken during the transport from the donor phase containing 0.1 M HCl to the acceptor phase containing pure water were determined by Liquid Chromatography Mass Spectrometry (LC-MS/MS). The permeability coefficient (P), rate constant (k), and material flow rate (J) values were calculated at the end of the transportation processes. The recovery factor (%) was determined to be 91.2 % at the end of 240 min of transportation time. The effects of relative amounts of the target analyte, carrier, and acid type on the donor phase were determined, as well as those of the acceptor phase pH and stirring effect. The results achieved in this study suggest that a stable and environmentally sustainable polymer inclusion membrane system might be used to effectively transport acetochlor.

The Role of Inorganic and Carbon Nanomaterials in Surface Modification to Attain Antibiofouling Polymeric Membranes for Water Treatment─A Review

Membrane biofouling is a major stumbling block in membrane technology and particularly in the water treatment industry. Biofouling, in particular, is a serious concern because it is irreversible and thus cuts the lifespan of the polymeric membranes. This review, therefore, explores the fundamentals of biofouling development and the factors that promote biofilm growth in polymeric membrane systems. In this pursuit, we discuss avenues through which antibiofouling polymeric membranes have been fabricated using inorganic and carbon-based nanomaterials as membrane nanofillers to enhance the hydrophilicity and antibiofilm properties of the resultant composite membranes without significantly compromising the membrane filtering abilities. We further elucidate the chemistry by which the membrane nanofillers mitigate or inhibit the formation and growth of the undesirable biofilms on the surface and pores of the membranes. In achieving this, recent works on polymeric membrane biofouling are reviewed, with a particular focus on the correlation between the membrane performance and the physicochemical properties of the filler nanomaterials. The merits and demerits of inorganic and carbon-based nanomaterials as fillers to confer an antibacterial effect to the membranes are presented and perspectives and opinions on the future direction of biofouling mitigation in membranes are outlined.

Method of evaluation of the transport properties in polymeric membrane systems using the Nr hybrid form of Kedem–Katchalsky–Peusner formalism

Method of evaluation of the transport properties in polymeric membrane systems using the Nr hybrid form of Kedem–Katchalsky–Peusner formalism

Quinuclidinium-piperidinium based dual hydroxide anion exchange membranes as highly conductive and stable electrolyte materials for alkaline fuel cell applications

Anion-exchange membrane fuel cells (AEMFCs) utilizing quaternary ammonium functionalized poly(arylene ether sulfone)s have been rapidly advanced in the clean energy research arena. However, it is highly desirable to integrate the benefits of quaternary ammonium cations in the polymeric membrane systems to achieve a high-power output together with substantial stabilities that significantly reduce the material costs. Herein, we report the tethering of two different quinuclidinium and piperidinium cations separated by a flexible –(CH2)4˗ spacer as a dual hydroxide conductor in the poly(arylene ether sulfone)s copolymer membrane (QP-PES) for enhancing the structural and physical properties as well as the ionic conductivities. The results proved that the tethering of dual hydroxide conductor in the PES backbone led to show maximum hydroxide conductivity of 88 mS cm−1 at 80 °C while enabling a hydrophilic/hydrophobic micro-phase separation due to the presence of flexible alkyl spacer. We also investigated the properties of a single hydroxide conductor exclusively comprising the quinuclidinium cation (Q-PES) and compared it with that of QP-PES. Interestingly, both the Q-PES and QP-PES membranes displayed superior thermal, mechanical, and dimensional stabilities. Most importantly, the QP-PES membrane demonstrated excellent alkaline stability over the period of 1000 h due to the existence of dual hydroxide conductor together with alkyl spacer units. Furthermore, the maximum power density of a H2/O2 single cell using QP-PES (92.3 mWcm−2) is higher than that of QP-PES (70.0 mWcm−2). The results provide a greater perception to design the high performance AEM materials.

Operando Surface-Enhanced Raman-Scattering (SERS) for Probing CO2 Facilitated Transport Mechanisms of Amine-Functionalized Polymeric Membranes.

This work describes a new operando surface enhanced Raman spectroscopy (SERS) platform that we developed for use with polymeric membranes that includes (1) a method for preparing SERS-active polymer membranes and (2) a permeation cell with optical access for SERS characterization of membranes under realistic operating conditions. This technique enables the direct correlation of membrane structure to its performance under realistic operating conditions by combining in situ SERS characterization of the molecular structure of polymer membranes and simultaneous measurement of solute permeation rates on the same sample. Using the new operando SERS technique, this work aims to clarify the unknown mechanisms by which reactive amines facilitate CO2 transport across polyvinylamine (PVAm), a prototypical facilitated transport membrane for CO2 separations. We show that a small amount of plasmonic silver particles added to the PVAm solution prior to knife-casting selectively enhances the sensitivity to detection of chemical intermediates (e.g., carbamate) formed in the PVAm film due to the surface-enhanced Raman scattering effect with only minimal effect on the CO2 permeance and selectivity of the membrane. Operando SERS characterization of PVAm during exposure to humidified CO2/CH4 biogas mixtures at room temperature shows that CO2 permeates across PVAm primarily as carbamate species. This work clarifies the previously unknown mechanism of CO2 facilitated transport across PVAm and establishes a new operando SERS platform that can be used with a wide range of polymer membrane systems. This technique can be used to elucidate fundamental transport mechanisms in polymer membranes, to establish reliable structure-performance relationships, and for real-time diagnostics of membrane fouling, among other applications.

Designing the feasible membrane systems for CO2 removal from Air-fed Anion-Exchange membrane fuel cells

Highly CO2 permeable membranes with good selectivity are ideal candidates for CO2 separation. Herein, we, for the first time, designed different polymeric membrane systems for CO2 removal from the air-fed anion-exchange membrane fuel cells (AEMFCs) by UniSim simulation under different operating conditions. The results indicate that the operations with higher feed pressure and permeate vacuum degree reduce the required membrane areas but increase the power demands. In addition, the single-stage facilitated transport membrane system (CO2 permeance of 3000 GPU) with an area of<10 m2 is feasible to reach a low CO2 content of < 5 ppm for automotive AEMFCs with an air flow rate of 30 Nm3/h at 87 °C. It was also found that pursuing an extremely high CO2 removal ratio dramatically increases the required membrane area and the O2 loss, and sweep gas is more applicable for automotive vehicles. Nevertheless, highly permeable membranes should be further developed to enhance their competitiveness for CO2 removal from the air-fed AEMFCs.

Methodology for the design of a multilayer polymeric membrane system with potential use in hemofiltration

Chronic kidney disease is generally complicated by poor care or by ignoring it. Among the causes that influence these conditions are obesity, diabetes, smoking, or genetic inheritance. Coordinated efforts are currently being made in multiple countries to control a strong case rate. The clinical techniques of treatment rely on the efficiency of blood purification (function that´s done by kidneys in organisms). Therefore, there is great interest in the development of devices that accomplish this function. Hemofiltration through porous membranes is an efficient process, but the flow conditions in a microchannel system can be complex. Analysis of blood flow in a parameterized conduit arrangement shows streams with desired trajectories, others are held back (stagnant), and others return to the stream from which it´s separated. In addition, the friction conditions and the reduction of the area drastically reduce the movement of the fluid, promoting clogging and consequently the inhibition of filtering. Based on these simulation results, it was proposed that the membrane coupling system could be modified to eliminate extensive flow in conduits generating a new concept of separation through a threshold.

Separation of Boron from Geothermal Waters with Membrane System

This study presents the separation and recovery of boron from geothermal waters with a polymeric membrane system and suggests a transport mechanism. The optimum relative parameters of the transport were examined. The recovery value of boron was 60.46% by using polymeric membrane system from prepared aquatic solution to the acceptor phase. The membrane’s capacity and selectivity of the transport process were examined. Kinetics values were calculated for each transport parameter. The optimum kinetic values were 1.4785 × 10−6 (s−1), 7.3273 × 10−8 (m/s), 13.5691 × 10−8 (mol/m2.s), 5.8174 × 10−12 (m2/s) for constant rate, permeability coefficient, flux, and diffusion coefficient, respectively. Boron was transported selectively and successfully from geothermal waters in the presence of other metal cations with 59.85% recovery value. This study indicates the application of real samples in polymeric membrane systems, which are very practical, economic, and easy to use for large-scale applications. The chemical and physical properties of polymer inclusion membranes (PIMs) offer the opportunity to be specially designed for specific applications.

Performance of exhaust detritiation system for a fusion test device in the initial phase of the operation

Abstract The exhaust detritiation system (EDS) has been operating for the deuterium plasma experiment in large fusion test device since 2016. The EDS consists of two systems: the molecular sieves (MS) type for plasma exhaust gas, the polymer membrane (PM) type for vacuum vessel purge gas during the maintenance activity. The tritium removal performance of the EDS was evaluated for four years. As the operation results, the maximum detritiation factor (DF) of the MS system was achieved to be more than 103 even though the average tritium concentration in the process gas was less than 104 Bq/m3. On the other hand, the DF of the PM system was less than 103, because the average tritium concentration during the vacuum vessel maintenance activity was at the order of less than 103 Bq/m3. Throughout the initial phase of the deuterium plasma experiment, the tritium concentration at the outlet of EDS was maintained to be less than the order of 102 Bq/m3. Also, a failure analysis was performed to evaluate the reliability of the EDS in the initial phase of the operation. Over the four years of operation, the overall failure rate of the MS system was on the order of 10−5 events/hour.

Performance Evaluation of Tight Ultrafiltration Membrane Systems at Pilot Scale for Agave Fructans Fractionation and Purification.

Ceramic and polymeric membrane systems were compared at the pilot scale for separating agave fructans into different molecular weight fractions that help to diversify them into more specific industrial applications. The effect of the transmembrane pressure of ultrafiltration performance was evaluated through hydraulic permeability, permeate flux and rejection coefficients, using the same operating conditions such as temperature, feed concentration and the molecular weight cut-off (MWCO) of membranes. The fouling phenomenon and the global yield of the process were evaluated in concentration mode. A size distribution analysis of agave fructans is presented and grouped by molecular weight in different fractions. Great differences were found between both systems, since rejection coefficients of 68.6% and 100% for fructans with degrees of polymerization (DP) > 10, 36.3% and 99.3% for fructooligosaccharides (FOS) and 21.4% and 34.2% for mono-disaccharides were obtained for ceramic and polymeric membrane systems, respectively. Thus, ceramic membranes are better for use in the fractionation process since they reached a purity of 42.2% of FOS with a yield of 40.1% in the permeate and 78.23% for fructans with DP > 10 and a yield of 70% in the retentate. Polymeric membranes make for an efficient fructan purification process, eliminating only mono-disaccharides, and reaching a 97.7% purity (considering both fructan fractions) with a yield of 64.3% in the retentate.

Modelling of mass transport and insulin secretion of a membrane-based encapsulation device of pancreatic islets

Widespread application of islet transplantation as a cure for type 1 Diabetes Mellitus patients is limited mainly due to the need for life-long immunosuppression associated with serious side effects. Immunoisolation by encapsulation of islets in semi-permeable membranes may overcome this issue as it allows for transplantation potentially obviating the need for immunosuppressive drug therapy.This work focuses on the development and validation of a model of the mass transfer and secretion kinetics of insulin – the major regulator of glucose homeostasis – in a new microwell membrane based encapsulation device for pancreatic islets. Due to the high number and complexity of parameters that determine the effectiveness of the device, the implementation of a reliable numerical model is of critical importance for optimization of the micro-confined bioengineered environment. The simultaneous solution of mass transfer and uptake/production reactions occurring through the polymeric membrane system and within the islets allows detailed description of the spatial distribution profiles of insulin, glucose, and oxygen with the aim to assure an adequate insulin dynamics. The simulation tool, experimentally validated, is used to improve the scaffold geometry with the aim to assure adequate responsiveness and function over time for future clinical implementation of the device.

Non-ideal modelling of polymeric hollow-fibre membrane systems: Pre-combustion CO2 capture case study

Some membrane gas separation applications operate at high temperature and pressure. However, the majority of membrane gas separation models employ simplifying assumptions which are not realistic under these conditions. In this study, a rigorous model is developed for polymeric hollow-fibre membrane modules incorporating non-isothermal separation (the Joule-Thomson effect), real gas behavior and concentration polarization. The model also accounts for temperature-dependent permeability, friction-based pressure loss on both feed and permeate sides and variable physical and transport properties. The rigorous model is applied for pre-combustion CO2 capture, i.e. CO2/H2 separation, and compared with a simplistic model for various polymeric membranes through changing temperature-independent activation energy of permeation and pre-exponential factor. Two types of H2- and CO2-selective membranes are then chosen for further analysis. As feed conditions change, the deviation between the rigorous and simplistic models ranges approximately from 2 to 12% for stage-cut and 2–20% for the permeate composition. The difference is mostly because of real gas behavior at low stage-cuts, while the Joule-Thomson effect adds to this behavior at high stage-cuts (≥40%) resulting in the greater deviation. The influence of concentration polarization, however, is found negligible even at high stage-cuts.

Synthetic organelles

One approach towards the creation of bottom-up synthetic biological systems of higher complexity relies on the subcompartmentalization of synthetic cell structures using artificially generated organelles - roughly mimicking the architecture of eukaryotic cells. Organelles create dedicated chemical environments for specific synthesis tasks - they separate incompatible processes from each other and help to create or maintain chemical gradients that drive other chemical processes. Artificial organelles have been used to compartmentalize enzyme reactions, to generate chemical fuels via photosynthesis and oxidative phosphorylation, and they have been utilized to spatially organize cell-free gene expression reactions. In this short review article, we provide an overview of recent developments in this field, which involve a wide variety of compartmentalization strategies ranging from lipid and polymer membrane systems to membraneless compartmentalization via coacervation.

Design and Synthesis of Imidazolium-Mediated Tröger's Base-Containing Ionene Polymers for Advanced CO2 Separation Membranes.

It is highly desirable to integrate the CO2 solubility benefits of ionic liquids (ILs) in polymeric membrane systems for effective CO2 separations. Herein, we are exclusively exploring a series of four novel imidazolium-mediated Tröger’s base (TB)-containing ionene polymers for enhanced CO2 separation. The two diimidazole-functionalized Tröger’s base monomers synthesized from “ortho”- and “para”-substituted imidazole anilines were polymerized with equimolar amounts of two different aromatic and aliphatic comonomers (α,α′-dichloro-p-xylene and 1,10-dibromodecane, respectively) via Menshutkin reactions to obtain four respective ionene polymers ([Im-TB(o&p)-Xy][Cl] and ([Im-TB(o&p)-C10][Br], respectively). The resulting ionene polymers having halide anions were exchanged with [Tf2N]− anions, yielding a novel Tröger’s base material [Im-TB(x)-R][Tf2N] or “Im-TB-Ionenes”. The structural and physical properties as well as the gas separation behaviors of the copolymers of aromatic and aliphatic Im-TB-Ionenes have been extensively investigated with respect to the regiochemistry of imidazolium groups at the ortho and para positions of the TB unit. The imidazolium-mediated TB-Ionenes showed high CO2 solubility and hence an excellent CO2/CH4 permselectivity of 82.5. The Im-TB-Ionenes also displayed good thermal and mechanical stabilities.

Investigation into the temperature effect on NOM fouling and cleaning in submerged polymeric membrane systems

Investigation into the temperature effect on NOM fouling and cleaning in submerged polymeric membrane systems

The effects of medium salinity on the delivery of carbon dioxide to microalgae from capture solvents using a polymeric membrane system

Efficient provision of carbon dioxide to microalgae is one of the major challenges to cost-effective large-scale cultivation. Previously, we have demonstrated the effectiveness of a novel membrane system in delivering CO2 to a marine strain of Chlorella sp. from CO2-loaded solvents. In this approach, the solvent is pumped through a non-porous hollow fibre membrane immersed in a microalgae medium, allowing passive transfer of CO2 that is utilised by the microalgae to enhance their growth, while simultaneously regenerating the solvent. In this article, we compare the growth of both fresh water and marine strains of algae using this membrane delivery system. While the fresh water medium has less pH buffering capacity and can dissolve less CO2, it proves similarly effective in delivering CO2 to the growing algae. Both the freshwater and marine species of Chlorella have slightly higher growth rates than the other species tested—Dunaliella tertiolecta and Haematococcus pluvialis. However, due to the lower osmotic pressure of the fresh water medium, more water is drawn through the membrane into the solvent than when the salt water medium is used. In conclusion, while CO2 delivery through the membrane system is effective for both salt and fresh water media, better performance is obtained for the salt water medium.

Dissipative Particle Dynamics Simulation for Clarifying Mechanism of Water Permeation in Polymeric Membranes

Polymeric membranes are widely used in engineering fields such as fuel cells and heat storage materials. The polymeric membrane has two properties, which are selective permeability and barrier. The selective permeation mean to let only certain substances pass through porimeric membrane. For example, it is used for fuel cells. The polymeric membrane used in fuel cells allow protons to pass through, but does not water and oxygen. Next, barrier is to not permeate anything. This is used for a microcapsule of a heat storage material and so on. The microcapsule is made of polymers and designed as substances in capsules are not discharged from it. In future, It will be used as CO2 separation technology or seawater desalination, which will be anticipated to solve global issues. However, the prediction and control of penetration into a membrane are still challenging subjects. In this research, we aimed to elucidate the mechanism of the water permeation. because water permeation is most basic. We performed molecular simulations of water transport through a polymeric membrane to clarify the key factors that dominate water permeation. We employed the dissipative particle dynamics (DPD) method. DPD method is a powerful mesoscopic simulation tool which enables the simulation of events occurring in millisecond timescales and on micrometre length scales. Since its introduction a decade ago, this method has been used to model various membrane cell systems, including the self-assembly of amphiphilic molecules interaction with rigid nanoparticles, and the effect of ligands and receptors in the membrane. Therefore, this method is suitable to simulate polymeric membrane system. we used model of actual molecules (COP (membrane polymer), sodium acetate (additive) and water). To determine the interaction parameters of the simulation models, we used the J-OCTA simulation software. We first computed the time-averaged mean square displacement (MSD) of water molecules to evaluate water permeability into a polymeric membrane. Then, MSD was also calculated for the additive system. Comparing of the systems, it was found that the water permeability decrease by adding additives (figure). The results were also reproduced in experiments and we get qualitatively same results. We found that additives enable the reduction of the water permeability into a polymeric membrane. In addition, we discussed polymer synthesis guideline decreasing water permeability. Figure 1

The transition from incoherent to coherent random laser in defect waveguide based on organic/inorganic hybrid laser dye

Abstract This paper systematically demonstrated a variety of experimental phenomena of random lasers (RLs) of N,N′-di-(3-(isobutyl polyhedral oligomeric silsesquioxanes)propyl) perylene diimide (DPP) organic/inorganic hybrid laser dye, which is composed of perylene diimide (PDI) as gain media and polyhedral oligomeric silsesquioxanes (POSS) as scattering media at a mole ratio of 1:2. In this work, we observe the transition from incoherent RL in the DPP-doped solutions and polymer membrane systems using dip-coating method to coherent RL in the polymer membrane system with defect waveguide using semi-polymerization (SP) coating method. Meanwhile, we found that the hybrid dye-DPP has a long lasing lifetime compared with the traditional laser dyes, which indicates that the POSS group can suppress the photo-bleaching effect to extend the working life of laser dyes.