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The study deals with nanofiltration for separating saccharides from phenolics and considers permeation of each individual sugar (mono- or disaccharide) from a plant hydrolysate compared to a model sugar solution. Experiments are carried out in a cross-flow flat-sheet cell (MaxiMem, Prozesstechnik GmbH) equipped with Nadir® NP030 P membrane. Nanofiltration in concentration and diafiltration mode has been investigated. It has been found that diafiltration mode ensures the appropriate conditions in the concentration polarization layer of the membrane that favors the sugar diffusion but prevents critical deposition and fouling.

The effect of the composition and pH of solutions on the transport of organic acids species in the anion exchange membrane (AEM) and adjacent diffusion layers has been investigated using voltamperomertry and chronopotentiometry. Carboxylic acids of varying number of carboxylic groups (acetic, malic and citric acid) were selected and their individual concentration in the mixture was varied to understand the influence of one molecule on the transport of other molecule in their mixture. Shape of the I-V and chronopotentiometric curves was influenced by pH and concentration. Detection of two limiting current densities (LCD) in I-V curves and inflection points in chronopotentiometric curves are due to change in species that are being transported in boundary layers and membrane. Results showed that LCD, resistance to ionic transport and concentration polarization were related to molar concentration and anionic equivalent charge calculated from Hydra-Medusa. Smaller size, higher mobility and charge density delayed the formation of concentration polarization. Electrolytes having ionic species with more anionic equivalent charge and larger Stokes radii were responsible for an early activation of overlimiting mechanisms and shorter plateau in I-V curve.

The development of novel materials with ion-selective nanochannels has introduced a new technology for harvesting salinity gradient (blue) energy, namely nanopore power generators (NPG). In this study, we perform a comprehensive analysis of the practical performance of NPG in both coupon-size and module-scale operations. We show that although NPG membrane coupons can theoretically generate ultrahigh power density under ideal conditions, the resulting power density in practical operations at a coupon scale can hardly reach 10 W·m−2 due to concentration polarization effects. For module-scale NPG operation, we estimate both the power density and specific extractable energy (i.e., extractable energy normalized by the total volume of the working solutions), and elucidate the impact of operating conditions on these two metrics based on the interplay between concentration polarization and extent of mixing of the high- and low-concentration solutions. Further, we develop a modeling framework to assess the viability of an NPG system. Our results demonstrate that, for NPG systems working with seawater and river water, the gross specific extractable energy by the NPG system is very low (~0.1 kW·h·m−3) and is further compromised by the parasitic energy consumptions in the system (notably, pumping of the seawater and river water solutions and their pretreatment). Overall, NPG systems produce very low net specific extractable energy (

Monoethylene glycol (MEG) aqueous solution was regenerated in the forward osmosis (FO) process for further use. For this purpose, a novel thin-film composite (TFC) membrane was prepared and applied. To mitigate the internal concentration polarization (ICP), a proper support with a low structural parameter and high hydrophilicity was utilized. In addition, a chlorine-tolerant polyamide layer was synthesized using trimesic acid trichloride (TMC) and 4-methyl-m-phenylenediamine (MMPD) monomers. The latter aimed to improve the chlorine resistance of the polyamide layer and increase the membrane lifespan in practical applications where oxidants are utilized for membrane cleaning. The effect of MMPD concentration and interfacial polymerization (IP) reaction time on the characteristics of the top layer was studied thoroughly. During the FO test, the TFC membrane whose polyamide layer was prepared with 2 wt. % MMPD concentration and 1.4 min reaction time exhibited the highest reverse flux selectivity at 5.71 L/g, while its water flux and MEG rejection during the regeneration of a MEG aqueous solution sampled from a gas processing plant were 35.40 LMH and 93.85%, respectively. The chlorine exposure test confirmed a significantly higher chlorine resistance for the MMPD/TMC polyamide layer compared to the conventional MPD/TMC one.

In order to solve the oxidation problem of the Ni-based solid oxide electrolysis cells (SOECs), SOECs with symmetrical electrode Sm0.5Sr0.5FeO3-δ- Gd0.1Ce0.9O2-δ (SSF-GDC) were systematically investigated, including the steam partial pressure, the working temperature, the electrolysis voltage. The reversible symmetrical cells with SSF-GDC electrode under humidified hydrogen presented good reversibility, and the maximum electrolysis current density was 1025 mA cm−2 at 800 °C with the applied voltage of 2V. In the case of direct N2 with 20% steam partial pressure as fuel, the symmetrical cells generated the maximum electrolysis current density increased from 267 to 1560 mA cm−2 at 650–800 °C. The influence of the steam partial pressure on the steam electrolysis showed that the maximum electrolysis current densities increased with the increase of the steam partial pressure from 3% to 20%, and the steam electrolysis with 3% steam partial pressure showed obvious concentration polarization due to insufficient steam partial pressure at high electrolysis current density. Finally, the short-term stability at different electrolysis voltages and long-term stability at the electrolysis voltage of 1.5V showed that there was no attenuation after 25 h operation, indicating that SSF-based symmetrical electrodes cab be an alternative to Ni-based fuel electrode materials for high-temperature steam electrolysis.

The performance of the existing forward osmosis membranes is mainly restricted by the internal concentration polarization (ICP) of solutes inside the substrate. In the current work, the poly (methyl methacrylate) (PMMA) grafted ZnO nanoparticle (ZnO@PMMA) was synthesized and introduced as a novel nanofiller to minimize the ICP effect within the polysulfone (PSf) support layer. It was revealed that the ZnO@PMMA nanoparticles could improve the characteristics of the PSf membrane substrate, including the porosity, hydrophilicity, pure water permeability (PWP) and morphology. The optimal support layer has a porosity of 82.4% and PWP of 186.5. The FO performance of modified membranes in terms of water flux (Jw, LMH) and reverse salt flux (Js, gMH) were thoroughly evaluated using a cross-flow system. Also, the water permeability (A, LMH.bar−1) and salt rejection (R, %) were measured by a dead-end RO setup. The obtained TFN-ZP.2 membrane (modified with 0.25 wt% of ZnO@PMMA) showed significantly improved FO water flux (up to 14.6 LMH) and water permeability (2.3 LMH/bar) which was about 2 times that of the bare TFC-FO membrane (5.9 LMH and 1.2 LMH/bar). Additionally, the structure parameter (S) was significantly alleviated (693 ± 85 µm) after the ZnO@PMMA incorporating, indicating reducing the unwanted ICP in TFN-FO membranes.

Selection, testing and validation of electrolyte candidates for Li-ion cells are discussed, based on a 10-minute target for extreme fast charge (XFC). A combination of modeling and laboratory measurements create a timely and synergistic approach to identifying candidate electrolyte formulations. Multi-solvent systems provide a balanced set of properties, wherein lower molecular-weight solvents offer reduced viscosity, increased species diffusivity, and mitigation of concentration polarization at high charge rates. Carefully selected formulations can exhibit peak conductivity and usable conductivity range of two to three times that of the baseline EC-EMC (3:7, wt.) + LiPF6. Candidates are also chosen based on stability and longevity within the cell environment. Lab testing coincides with property predictions from the Advanced Electrolyte Model (AEM) and a macro-scale cell model. Cell testing utilized coin and pouch cells having NMC532 or NMC811 cathodes with graphite electrodes. Results indicate combinations of low-molecular weight solvents are key for fast-charge electrolytes as they extend the useful conductivity range to both low and higher salt concentrations, and possess higher self-diffusivities compared to conventional solvents. This reduces impacts from concentration polarization. The choice of electrolyte also influences the tendency for lithium metal deposition at the anode, as showcased by experimental and modeling results herein.

A concise and accurate prediction method is required for membrane permeability in chemical engineering and biological fields. As a preliminary study on this topic, we propose the concentration polarization model (CPM) of the permeate flux and flow rate under dominant effects of viscosity and solute diffusion. In this model, concentration polarization is incorporated for the solution flow through a semi-permeable membrane (i.e., permeable for solvent but not for solute) in a circular pipe. The effect of the concentration polarization on the flow field in a circular pipe under a viscous-dominant condition (i.e., at a low Reynolds number) is discussed by comparing the CPM with the numerical simulation results and infinitesimal Péclet number model (IPM) for the membrane permeability, strength of the osmotic pressure, and Péclet number. The CPM and IPM are confirmed to be a reasonable extension of the model for a pure fluid, which was proposed previously. The application range of the IPM is narrow because the advection of the solute concentration is not considered, whereas the CPM demonstrates superior applicability in a wide range of parameters, including the permeability coefficient, strength of the osmotic pressure, and Péclet number. This suggests the necessity for considering concentration polarization. Although the mathematical expression of the CPM is more complex than that of the IPM, the CPM exhibits a potential to accurately predict the permeability parameters for a condition in which a large permeate flux and osmotic pressure occur.

Two-dimensional materials-based membranes continue attracting research interest due to the ultrafast permeance and effective molecular sieving. However, measuring the nanofiltration performance of an ultrafast membrane under long-term filtration remains elusive, particularly when considering the effects of concentration polarization and cake formation on the flux decline and rejection rate. To address this question, we designed an ultrafast graphene oxide (GO) membrane using small-flake graphene oxide (SFGO) on the lateral scale of ∼100 nm, which was prepared using sonication. The SFGO membrane exhibited ultrafast permeance of 720–5410 L m−2 h−1 bar−1 for several solvents (i.e., acetone, methanol, water, ethanol, and isopropyl alcohol), which could be attributed to the reduced diffusion length and increased effective membrane surface area. It was observed a drastic flux and rejection rate decline in both water and isopropyl alcohol in the filtration of several dye solutions using dead-end and cross-flow systems. This could be attributed to the concentration polarization and cake formation that occurred during the rapid accumulation of solute on the membrane surface due to the ultrafast solvent permeance.

[ES] La alta cuenca del río Guadalquivir ubicada en el departamento de Tarija, Bolivia, alberga al municipio de la ciudad capital de Tarija; siendo la zona urbana más poblada del departamento. Durante las últimas décadas el departamento ha tenido grandes ingresos económicos, producto de la explotación hidrocarburífera, trayendo consigo un crecimiento poblacional e inmobiliario desproporcionado; originando un proceso de contaminación y degradación ambiental, producto de actividades antrópicas como la disposición de aguas residuales con poco o nulo proceso de tratamiento, desechos sólidos en las orillas del río, y sobreexplotación de áridos. En consecuencia, varias fuentes de abastecimiento de agua se encuentran paralizadas. Durante los últimos años, la problemática ambiental e hídrica ha sido objeto de un permanente debate, sin encontrar soluciones sostenibles en el corto plazo, ocasionando que la degradación ambiental permanezca activa con altos riesgos para la salud púbica. Siendo necesario conocer el estado actual de los recursos hídricos en la cuenca, se realizaron dos trabajos iniciales; se modeló el balance hídrico de la cuenca para establecer la disponibilidad de agua. Para este proceso se realizó una investigación de apoyo destinada a clasificar y determinar las propiedades de los suelos en la cuenca para lograr una menor incertidumbre en los resultados de la modelación hidrológica. Los resultados determinaron que existe un déficit de agua, principalmente en las épocas de estiaje. Un segundo estudio ha sido destinado a conocer la calidad del agua mediante un monitoreo de las principales fuentes de abastecimiento de agua potable. La investigación a las fuentes primarias de agua en la cuenca de estudio identificó la presencia de metales pesados tóxicos para la salud que exceden los límites permisibles para el agua potable. Se identificó plomo, manganeso y hierro presente en los embalses de San Jacinto y Huacata; mientras que el Pb excede en un 50% de lo establecido en la Normativa, el Mn y el Fe superan hasta 800% la norma actual. El trabajo estudia la ósmosis inversa (OI) para eliminar el Pb, Mn y Fe en distintas concentraciones. La principal contribución de esta investigación es el desarrollo y construcción de un modelo matemático novedoso basado en el modelo de concentración de polarización de Spiegler-Kedem. El modelo ha sido desarrollado utilizando diferentes concentraciones de Pb, Mn y Fe. La selección de las concentraciones se basa en construir un modelo que permita el diseño de instalaciones con alta conversión (>80%). Con ello será posible optimizar el proceso desde el punto de vista de eficiencia energética en futuros trabajos. El modelo incluye, además, un factor de ajuste de temperatura tipo Arrhenius que permite una predicción precisa del rendimiento del proceso. La experimentación se llevó a cabo en una planta piloto de OI utilizando una membrana compuesta de poliamida de configuración en espiral tipo ULP 2540 Marca Keensen de procedencia China. La validación del modelo se ajusta correctamente con un error relativo máximo entre los flujos experimental y teórico de 5,4%, 18% y 7.6% para el Pb, Mn y Fe respectivamente. Entre los principales beneficios del estudio, permite garantizar el rechazo de metales superior al 99%, incluso a bajas presiones, garantizando agua segura a la población de Tarija. Como un aporte final se propone un análisis de las partes interesadas en la cuenca, logrando identificar, clasificar y relacionar los diferentes actores con poder e interés en el proyecto., [CA] L'alta conca del riu Guadalquivir ubicada en el departament de Tarija, Bolívia, alberga al municipi de la ciutat capital de Tarija; sent la zona urbana més poblada del departament. Durant les últimes dècades el departament ha tingut grans ingressos econòmics, producte de l'explotació hidrocarburífera, comportant un creixement poblacional i immobiliari desproporcionat; originant un procés de contaminació i degradació ambiental, producte d'activitats antròpiques com la disposició d'aigües residuals amb poc o nul procés de tractament, rebutjos sòlids a la vora del riu, i sobreexplotació d'àrids. En conseqüència, unes quantes fonts d'abastiment d'aigua es troben paralitzades. Durant els últims anys, la problemàtica ambiental i hídrica ha sigut objecte d'un permanent debat, sense trobar solucions sostenibles en el curt termini, ocasionant que la degradació ambiental romanga activa amb alts riscos per a la salut púbica. Sent necessari conéixer l'estat actual dels recursos hídrics en la conca, es van realitzar dos treballs inicials; es va modelar el balanç hídric de la conca per a establir la disponibilitat d'aigua. Per a este procés es va realitzar una investigació de suport destinada a classificar i determinar les propietats dels sòls en la conca per a aconseguir una menor incertesa en els resultats de la modelació hidrològica. Els resultats van determinar que hi ha un dèficit d'aigua, principalment en les èpoques d'estiatge. Un segon estudi ha sigut destinat a conéixer la qualitat de l'aigua per mitjà d'un monitoreo de les principals fonts d'abastiment d'aigua potable. La investigació a les fonts primàries d'aigua en la conca d'estudi va identificar la presència de metalls pesants tòxics per a la salut que excedixen els límits permissibles per a l'aigua potable. Es va identificar plom, manganés i ferro present en els embassaments de Sant Jacinto i Huacata; mentres que el Pb excedix en un 50% del que establix la Normativa, el Mn i el Fe superen fins a 800% la norma actual. El treball estudia l'osmosi inversa (OI) per a eliminar el Pb, Mn i Fe en distintes concentracions. La principal contribució d'esta investigació és el desenrotllament i construcció d'un model matemàtic nou basat en el model de concentració de polarització de Spiegler-Kedem. El model ha sigut desenrotllat utilitzant diferents concentracions de Pb, Mn i Fe. La selecció de les concentracions es basa a construir un model que permeta el disseny d'instal·lacions amb alta conversió (>80%). Amb això serà possible optimitzar el procés des del punt de vista d'eficiència energètica en futurs treballs. El model inclou, a més, un factor d'ajust de temperatura tipus Arrhenius que permet una predicció precisa del rendiment del procés. L'experimentació es va dur a terme en una planta pilot de OI utilitzant una membrana composta de poliamida de configuració en espiral tipus ULP 2540 Marca Keensen de procedència Xina. La validació del model s'ajusta correctament amb un error relatiu màxim entre els fluxos experimental i teòric de 5,4%, 18% i 7.6% per al Pb, Mn i Fe respectivament. Entre els principals beneficis de l'estudi, permet garantir el rebuig de metalls superior al 99%, inclús a baixes pressions, garantint aigua segura a la població de Tarija. Com una aportació final es proposa una anàlisi de les parts interessades en la conca, aconseguint identificar, classificar i relacionar els diferents actors de poder i interés en el projecte., [EN] The upper basin of the Guadalquivir River located in the department of Tarija, Bolivia, houses the municipality of the capital city of Tarija; being the most populated urban area of the department. During the last decades the department has had great economic income, as a result of hydrocarbon exploitation, bringing with it a disproportionate population and real estate growth, originating a process of contamination and environmental degradation, product of anthropic activities such as the disposal of wastewater with little or no treatment process, solid waste on the banks of the river, and overexploitation of aggregates. Consequently, various sources of water supply are paralyzed. In recent years, environmental and water problems have been the subject of permanent debate, without finding sustainable solutions in the short term, causing environmental degradation to remain active with high risks to public health. Being necessary to know the current state of the water resources in the basin, two initial works were carried out; the water balance of the basin was modeled to establish the availability of water. For this process, a support investigation was carried out to classify and determine the properties of the soils in the basin to achieve less uncertainty in the results of the hydrological modeling. The results determined that there is a water deficit, mainly in the dry season. A second study has been designed to determine the quality of the water by monitoring the main sources of drinking water supply. The investigation of the primary water sources in the study basin identified the presence of toxic heavy metals for health that exceed the permissible limits for drinking water. Lead, manganese, and iron present in the San Jacinto and Huacata reservoirs were identified; while Pb exceeds by 50% what is established in the Regulation, Mn and Fe exceed up to 800% the current standard. The work studies reverse osmosis (RO) to eliminate Pb, Mn and Fe in different concentrations. The main contribution of this research is the development and construction of a novel mathematical model based on the Spiegler-Kedem concentration polarization model. The model has been developed using different concentrations of Pb, Mn and Fe. The selection of the concentrations is based on building a model that allows the design of installations with high conversion (>80%). With this it will be possible to optimize the process from the point of view of energy efficiency in future works. The model also includes an Arrhenius-type temperature adjustment factor that allows accurate prediction of process performance. The experimentation was carried out in a RO pilot plant using a ULP 2540 Keensen brand spiral configuration polyamide composite membrane from China. The model validation fits correctly with a maximum relative error between the experimental and theoretical fluxes of 5.4%, 18% and 7.6% for Pb, Mn and Fe respectively. Among the main benefits of the study, it allows to guarantee the rejection of metals higher than 99%, even at low pressures, guaranteeing safe water to the population of Tarija. As a final contribution, an analysis of the interested parties in the basin is proposed, managing to identify, classify and relate the different actors with power and interest in the project.

The forward osmosis membrane (FO membrane) is an emerging wastewater treatment technology in bioelectricity generation, organic substrate removal and wastewater reclamation. Compared with traditional membrane materials, the FO membrane has a more uniform water content distribution and internal solution concentration distribution. In the past, it was believed that one of the important factors restricting power generation was membrane fouling. This study innovatively constructed a mass transfer model of a fouling membrane. Through the analysis of the hydraulic resistance coefficient and the salt mass transfer resistance coefficient, the driving force and the tendency of reverse salt flux during membrane fouling were determined by the model. A surprising discovery was that the fouling membrane can also achieve efficient power generation. The results showed that the hydraulic resistance coefficient of the fouling membrane increased to 4.97 times the initial value, while the salt mass transfer resistance coefficient did not change significantly. Meanwhile, membrane fouling caused concentration polarization in the FO membrane, which enhanced the reverse trend of salt, and the enhancement effect was significantly higher than the impact of the water flux decline caused by membrane pollution. This will make an important contribution to research on FO membrane technology as sustainable membrane technology in wastewater treatment.

Benefiting from large tunnel structure, zero strain feature, and excellent pseudocapacitive performance, Ti2Nb10O29 was considered as a potential anode material for lithium-ion batteries (LIBs). Herein, Ti2Nb10O29 cages comprised of nanorod units were elaborately designed. The mesoscopic structure could effectively shorten the ion diffusion pathway, and the big central electrolyte reservoir relieves the concentration polarization of electrolyte. Moreover, the perforated pore feature guarantees competent contact between electrolyte and framework. As the anode of LIBs, the mesoscopic Ti2Nb10O29 cages deliver high reversible capacity (302.5 mAh/g) and rate capability (134.3 mAh/g at 30 A/g). This unique mesoscopic structure holds excellent potential for the electrode design of high-rate and long-life LIBs.

This article presents a 1D classification and analysis of mathematical models of binary salt ion transport in electromembrane systems. The various phenomena of concentration polarization occurring in these systems are studied using mathematical models, both individually and in combination with each other. In accordance with this, we have carried out the classification of these phenomena, problems and mathematical models. The article presents a hierarchy of subordination of 1D mathematical models. A brief review, comparison, and analysis of the results of the boundary value problems from the proposed hierarchy are carried out. A numerical study and comparison of some mathematical models from the proposed hierarchy are carried out. The scope of applicability and limitations for each model are defined.

Zero-dimensional carbon dots have emerged as important nanofillers for the separation membrane due to their small specific size and rich surface functional groups. This study proposed a strategy based on hydrophobic carbon dots (HCDs) to regulate water channels for an efficient forward osmosis (FO) membrane. Thin-film composite (TFC) membranes with superior FO performance are fabricated by introducing HCDs as the nanofiller in the polyacrylonitrile support layer. The introduction of HCDs promotes the formation of the support layer with coherent finger-like hierarchical channels and micro-convex structure and an integrated polyamide active layer. Compared to the original membrane, TFC-FO membrane with 10 wt% HCDs exhibits high water flux (15.47 L m−2 h−1) and low reverse salt flux (2.9 g m−2 h−1) using 1 mol/L NaCl as the draw solution. This improved FO performance is attributed to the lower structural parameters of HCDs-induced water channels and alleviated internal concentration polarization. Thus, this paper provides a feasible strategy to design the membrane structure and boost FO performance.

Vanadium redox flow battery (VRFB) is the best choice for large-scale stationary energy storage, but its low energy density affects its overall performance and restricts its development. In order to improve the performance of VRFB, a new type of spiral flow field is proposed, and a multi-physics coupling model and performance metrics evaluation system are established to explore the electrolyte distribution characteristics. The results show that the new spiral flow field can effectively improve the uniformity of electrolyte flow and alleviate the phenomenon of local concentration polarization as compared with the traditional serpentine flow field and parallel flow field. Due to the long flow channel and large pressure drop, the system efficiency is low. However, coulombic efficiency, voltage efficiency and energy efficiency are significantly better than the traditional flow fields. Therefore, the novel flow field has obvious advantages in the application of small stacks.

The desalination of water in the steady-state and pulsed modes of the supply of the voltage, the value of which corresponds to the conditions of overlimiting current, has been experimentally investigated. The dependences of the current flowing through the electrodialyzer, the water conductivity, and the content of single and double-charged cations at the outlet of the desalination chamber on the value of the applied voltage, the rate of liquid pumping through the electrodialyzer, the initial salt concentration, and the frequency are analyzed. It is shown that the pulsed mode demonstrates, in comparison with the steady-state mode, a decrease in the concentration polarization of the membranes and an increase in the mass transfer in the electrodialyzer in the entire range of used parameters. In addition to the previously proposed mechanism based on the inertia of electroosmosis of the second kind, the increase in mass transfer can be explained by changes in the electromigration mobility of ions, the turbulence of fluid in the intermembrane channel, and the emergence of a bias current and a magnetic field due to voltage pulses in an electric double layer. Considerable attention is also paid to studying the purification of water from cations with different charges. It is found that the removal of zinc cations from the desalination chamber significantly exceeds the removal of sodium cations, which is consistent with previous experimental studies for calcium and sodium cations. However, the obtained results contradict the currently existing three-ion models of competitive ion transport with predominance of the transfer of double-charged cations in the undercurrent mode and single-charged cations in the overcurrent mode. The discrepancy is explained by the dependence of the concentration polarization of the membranes and, accordingly, the transport of salt ions across the membranes on the dissociation of water in the region of space charge, which leads to competitive transport of five ions rather than three ions.

The membrane fouling is the main bottleneck hindering the wide applications of anammox-membrane bioreactor (MBR). In this study, surface-coating hydrophilic modification of the membrane using polyvinyl alcohol was applied in a granular anammox-MBR. Stable anammox performance of >77% total nitrogen removal efficiency was achieved in both original and modified MBRs, along with decreasing anammox granule size. The modified membrane exhibited superior flux performance, and the membrane foulants were reduced in the MBR operation. Specifically, the foulant formation rate (f) was 0.46 g·m-2·d-1 for the modified membrane with 100-μm coating thickness (M100) compared with 0.75 g·m-2·d-1 for the original membrane (M0). However, the fouling cycle of the modified membrane with 250-μm coating thickness (M250) was greatly shortened (5 days compared with 19 days for M0) and f increased to 1.25 g·m-2·d-1. Specially, the excess adhesion of exopolysaccharides and humic substances to the hydrophilic modified membrane changed the fouling layer structure and filtration resistance distribution, ultimately causing higher filtration resistance when coating thickness increased. Notably, the flux decline contribution of the concentration polarization was only 33.3% for M0, while it was 71.3% for M250. Finally, it was revealed that using a modified membrane increased the biological secretion rate of polysaccharide but decreased the protein bio-production rate, leading to a high PS (polysaccharide)/PN (protein) ratio in the MBR. The fouling mechanism of the hydrophilic modified membrane applied in anammox-MBR was proposed, and we highlight that the degree of hydrophilic modification is crucial to mitigating membrane fouling.

Показано закономірності сумісного розряду двох іонів для різних умов поляризації електрода: концентраційної, змішаної (концентраційно-кінетичної) та кінетичного контролю у випадку сповільненого розряду обох іонів. Показано, як незалежні процеси розряду іонів стають залежними при сумісному розряді. Отримано рівняння поляризаційної кривої для електрохімічного синтезу у випадку концентраційної поляризації електрода (розглянуто сумісний розряд двох іонів та подальша сповільнена гетерогенна хімічна реакція синтезу). При цьому зсув перенапруги залежить від величини заряду іонів, що розряджаються, густини струмів розряду та густини струму обміну хімічної реакції синтезу, різниці величин стандартних потенціалів. The mechanisms of simultaneous discharge of two ions for different conditions of electrode polarization [concentration polarization, mixed (concentration-kinetics) polarization, and kinetic control in the case of delayed discharge of both ions] are shown. We show how the independent processes of discharge of ions become dependent at the simultaneous discharge. The equation of polarization curve for the electrochemical synthesis in the case of concentration polarization of the electrode is derived (we consider the simultaneous discharge of two ions and the proceeding delayed heterogeneous chemical reaction of synthesis). The overvoltage shift depends on the charge of ions discharged, density of discharge currents, density of exchange current of the chemical reaction of synthesis, and difference in the standard potentials.

A method is developed for calculating the values of concentration polarization during the separation of an aqueous solution containing anionic surfactants for ultrafiltration membranes with ideal and non-ideal rejection coefficients in a wide range of changes in the values of the diffusion Peclet number.

The paper discusses experimental data on the mutual effect of concentrations of NaCl and MgCl2 salts during their transport across a Vontron VNF2-1812 nanofiltration membrane at low specific loads of the feed stream, which imply the occurrence of concentration polarization near the membrane surface. Separation is run at a minimum difference between the operating pressure maintained in the forcing channel (0.3 MPa) and the calculated osmotic pressure (0.25 MPa for all individual and mixed solutions used). It is shown that, under the studied conditions, the water flux is almost independent of the ratio of salt concentrations in the solution in the separation chamber; with an increase in the specific load of the feed stream on the membrane, the water flux exhibits a tendency to achieving a limiting value. It is found that, for conditionally isopiestic NaCl and MgCl2 solutions, the dependence of the salt flux on the molar fraction of the respective salt is nonlinear. This finding can be attributed to the nonlinear relationship between the absolute and relative concentrations of salts in the feed stream and the dependence of their interdiffusion coefficients in mixed solutions on composition. Techniques to improve the efficiency of the nanofiltration separation of differently charged cations are described.

The aim of this research is to investigate the removal behavior of iron and manganese that naturally exist as divalent ions in groundwater by using nanofiltration membranes. The main focus of this study is to better understand the effect of applied pressures during the rejection of these metallic ions from synthetic groundwater in order to achieve drinking water standard. Polyamide and polypiperazine amide nanofiltration membranes denoted as PA-NF and PPA-NF were selected to investigate the iron and manganese rejection at low applied pressures (1-5 bar). In single solute solution with feed concentration at 10 mg/L and initial pH of 6.8 ± 0.5, the rejection of iron was ≥96% by PA-NF membrane at applied pressure of 2 bar. However, the rejection percentage by PPA-NF was 86.6% whereby this membrane unable to remove iron to the allowable drinking water standard. The rejection of manganese with single solute at concentration of 1 mg/L with initial pH of 6.8 ± 0.5 by using the PA-NF membrane was ≥98% and almost all of dissolved manganese were rejected at 5 bar. However, manganese removal by PPA-NF membrane was found less than 70% for all of the applied pressures. Findings from this work showed that the removal of iron and manganese were dependent on the applied pressures. PA-NF membrane able to remove both metallic ions that comply with the drinking water standard. The increased of applied pressure contributed to concentration polarization effect on the membrane surfaces leading to a decrease in solute rejection by decreasing the charge effect mainly for the iron removal from synthetic groundwater.

The practical application of lithium (Li) metal anode has been hindered by the fast Li depletion and shallow cycling conditions. Herein, a universal and scalable approach for current collectors combining an enhanced lithiophilic surface and a conductive inner core enables a promising pathway for high−performance Li metal battery (LMB). The interface between anode and electrolyte accelerates Li ions self−concentration and enhances the electrokinetic surface conduction with suppressed Li concentration polarization. With Cu@Cu3N as an example, a fast Li plating/stripping at 20 mA cm−2 for 10,000 cycles and a stable full cell under the near realistic conditions with a high active material loading (19.1 mg cm−2), a low electrolyte/active materials ratio (2.3), and a limited Li resource (10.24 mAh cm−2: equivalent to 50 µm Li foil) are achieved for broadening the commercialization of LMB.

In view of the disadvantages of concentration polarization and trade-off effects in the application of membrane in desalination field, oxide-nano graphene oxide/polyamide (O-NGO/PA) loose intermediate layer and PA ultra-thin dense layer were introduced to fabricate PA/O-NGO/polyphenylene sulfide composite membrane with sandwich structure via multi-step interfacial polymerization (MS-IP) method. The selective permeation mechanism of ultrathin layer produced by different aqueous monomers (PIP and MPD) was studied, the effect of its physicochemical structure on the relief of concentration polarization phenomenon and the breakthrough of trade-off effect was analyzed. The ultra-thin and dense PA layer mainly played the role of interception and shortened the water molecular penetration path. In the retention test of metal salt solution, compared with the rough surface, it was found that the smooth surface was more conducive to the diffusion of intercepted metal ions into the feed solution, thus alleviating the concentration polarization phenomenon.

Membrane reactors are a potential tool to produce high purity hydrogen on-site but sufferfrom immense losses in hydrogen recovery under reaction conditions. For high-temperature operations, these losses mostly occur due to the presence of lesser permeable gases in the reformate that develop into a concentration polarization barrier around the membrane. Based on our previous findings, a multi-pass design was manifested to alleviate hydrogen losses through the membrane tested with synthetic gas mixtures. The same design is currently employed to establish improvement in hydrogen recovery under reaction conditions. Having a catalyst and membrane integrated into a single unit termed as a membrane reactor, its performance is optimized with varying membrane assembly and catalyst bed configurations. This study shows that a packed bed multi-pass membrane reactor is an optimal design to target high hydrogen recovery. Further, multi-pass membrane reactor design also improves the hydrogen recovery in fluidized bed operations which opens immense scope for future studies.

Based on a hybrid Eulerian-Lagrangian approach, erosion characteristic of membrane tubes in a membrane-assisted fluidized bed reactor is numerically evaluated. The erosion rate of Pd-based membrane is integrated. The influence of hydrogen separation on gas-solid hydrodynamics and erosion characteristics is discussed. The relationship between concentration polarization and membrane tube erosion is examined. The results demonstrate that the maximum wear of Pd-based membrane occurs at the normal angle. The hydrogen separation weakens membrane tube erosion in a fluidized bed. The arrangement of membrane tube locations plays a very important role in tube erosion. The non-uniform hydrogen concentration strengthens the maximum membrane tube wear, especially for the bottom of the fluidized bed reactor.

In the present work, optimized ultrafiltration conditions, using a ceramic multi tubular titania membrane (150 KDa), were investigated for the treatment of tuna cooking juice, for water reuse in the industrial process. The interactive effects of the volume concentrating factor (VCF) (1.03–4.25), feed temperature (T) (20–60 °C), and applied transmembrane pressure (ΔP) (2–5 bar) on protein removal (R protein) and permeate flux (J) were determined. A Box–Behnken experimental design (BBD) with the response surface methodology (RSM) was used for statistical analysis, modeling, and optimization of the operating conditions. The analysis of variance (ANOVA) results proved that the protein removal and permeate flux were significant and represented good correlation coefficients of 0.9859 and 0.9294, respectively. Mathematical modeling showed that the best conditions were VCF = 1.5 and a feed temperature of 60 °C, under a transmembrane pressure of 5 bar. The fouling mechanism was checked by applying a polarization concentration model. Determination of the gel concentration confirmed the results found in the mass balance calculation and proved that the VCF must not exceed 1.5. The membrane regeneration efficiency was proven by determining the water permeability after the chemical cleaning process.

In many membrane-based water treatment methods, because of consistent salt fouling on the membranes of the narrow feed channel, studying methods of improving the fluid flow and mass transfer of the membrane element is vitally important. Providing a slippery situation for the fluid adjacent to the membrane can result in concentrated fluid movement and system operation improvement. In this research, the effects of various magnitude of slip velocities on the important parameters of membrane feed channel operation at the wide range of Reynolds numbers have been investigated. To this end, CFD has been implemented and the continuity, Navier–Stokes, and mass transfer equations in a 2D narrow channel have been solved. Two cases with and without slip velocity have been compared comprehensively in the wide range of Reynolds numbers from 100 to 2100. Also, the influence of fluid properties variations with the salt concentration on output results has been studied. Due to the induced slip velocity, the results demonstrate a decline of about 5–12% in concentration polarization, an increase of 20–60% in Sherwood number, a decrease of 5–13% in friction factor, and an increase of 0.5–1.5% in permeation flux.

This paper provides a mathematical simulation model for the reverse osmosis (RO) process with series elements. A mathematical simulation model was developed based on the mass, material and energy balances considering the concentration polarization. The simulation model is open-source and easy to couple with other computational tools like optimization algorithms and SCADA1 applications. An RO laboratory pilot was also set up in the Hydraulic Lab of Shahid Chamran University of Ahvaz to validate the simulation results. Comparing the results of the simulation model with the experiments and ROSA commercial software, the proposed simulation model functions well and is reliable. The comparisons indicate that the simulation results are over 96% close to ROSA and over 80% close to experimental results.

The core of this study was fabrication of novel cellulose acetate/pluronic F-127 (CA/PF-127) composite membranes for forward osmosis (FO) applications. Performance and structure of the FO membranes under the influence of different applicator clearance gaps (ACGs) along with PF-127 wt.% contents were examined during the non-solvent phase separation (NIPS) method. Scanning electron microscopy, water contact angle, atomic force microscopy and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis were used to characterize the membrane properties. The best performance was attributed to the lower thickness and the higher porosity. The lower structural parameter, which reduces the internal concentration polarization (ICP), led to the highest water flux. The values of 10.58 (L/m2.h) and 0.39 (g/L) were obtained as water flux and specific reverse salt flux (SRSF) of the optimal FO membrane, which was synthesized by 20 wt.% of CA, 79.00 wt.% of N-methyl-2-pyrrolidone (NMP), 1.0 wt.% of PF-127 and 100 µm of ACG, respectively.

The electrochemical performance of an electrode supported protonic ceramic electrochemical cell (PCEC) often suffers from high mass transport resistances, especially at high current densities. Here, we report our findings in the structure tailoring of the electrode substrate to facilitate mass transport via a modified phase inversion technique, ultimately resulting in lower polarization resistances and higher outputs. A Ni–BaZr0.1Ce0.7Y0.1Yb0.1O3 (BZCYYb) substrate, with straight and open finger-like pores (∼30–80 μm in diameter; ∼500 μm in length), has been successfully fabricated via tape casting and phase inversion of a graphite layer and a substrate layer sequentially. Single cells with such a unique microstructure demonstrate better electrochemical performance when compared with dry-pressed cells under the same conditions. For example, when operated in a fuel cell mode, a peak power density of 1.389 W cm−2 and a polarization resistance of ∼0.039 Ω cm2 at 700 °C (vs. 0.929 W cm−2 and 0.113 Ω cm2 for dry-pressed cells) have been achieved when using hydrogen (with 3% H2O) as the fuel and ambient air as the oxidant. Furthermore, a current density of ∼−2.066 A cm−2 has been achieved at 1.3 V when the cell is operated in an electrolysis mode (3% steam in air) at 700 °C, much higher than that for dry pressed cells (only ∼−1.615 A cm−2 at 1.3 V). Since the air electrode and electrolyte are kept the same, the performance improvement can be attributed to the facilitated mass transport within the electrode substrate. It is concluded that the presence of finger-like pores facilitates the mass transportation in the substrate, thereby reducing the concentration polarization.

Volume expansion and “dead Li” accumulation in the Li anode forbid the development of practical pouch-cell type Li metal batteries (pLMBs). Thus, development of highly reversible and long-life Li metal anodes is of great importance in this area. Herein, a facile thermally initiated conversion method is proposed to fabricate a Li/graphene composite anode (Li@G) by a heating induced local reaction among Li powder, graphene and PVDF. Using simple mixing–coating–drying–heating procedures, a large-area Li@G anode can be prepared in a roll-to-roll way with a film casting machine. The detailed morphology and functions of the LiC6 skeleton in this composite anode on alleviating “dead Li” accumulation are confirmed. Failure analysis and morphology characterization demonstrate the improvement in reducing cell resistance and concentration polarization by using this novel Li anode. As a result, a 0.55 A h pLMB (Li@G/NCM811) strictly following practical conditions can cycle stably 140 times due to the improved reversibility of Li stripping/plating. Moreover, a 2.6 A h pLMB (Li@G/NCM811) delivers a high energy density of 356 W h kg−1 (based on the whole cell) with a high capacity retention of 70% for 100 cycles. The scalable preparation method of the advanced Li@G anode presented in this paper makes promising progress in design and fabrication of Li composite anodes for practical pLMBs.

In this study, a two-dimensional, two-phase, non-isothermal and steady-state modified model of proton exchange membrane fuel cells is developed. The Forchheimer's effect (Non-Darcy effect) is coupled in the model, and its impact on liquid water removing process in flow channels with baffles having different shapes is discussed. Simulation results show that the liquid water is able to be removed more at the regions around baffles. At the same time, the baffle shapes reform the liquid water distribution. When using the baffles having larger dimensions (e.g. using rectangular baffles or trapezoidal baffles), the flow spaces around baffles decrease more and the liquid water is removed more because of the increase in local flow velocity. As a result, the concentration polarization is weakened and cell performance is improved more. Moreover, a streamline baffled flow channel that is designed for the purpose of both increasing the cell performance and avoiding excessive increase in pressure drops is discussed. Simulation results show that this flow channel design can both avoid too much increase in pressure drop and facilitate the liquid water removing out from the fuel cell.

High water flux and salt selectivity have been the most demanding goals for osmosis-based membranes. Osmotic pressure differences across membranes are particularly important in emerging forward osmosis and pressure retarded osmosis applications, and they are strongly dependent on internal concentration polarization (ICP) and water permeability. Here, we have studied the influence of hydrophobic straight pores perpendicular to the membrane plane and super-hydrophilic metal–organic frameworks (MOFs) on membrane performance. We found that straightening the pores in the supporting layer significantly reduced flow resistance. While water can pass through the hydrophobic supporting layer with minimal interaction, the hydrophilic MOF in the active layer effectively attracts water to the membrane, synergistically augmenting water permeability without considerable reduction of salt rejection. The low tortuosity by straightening the pores in the supporting layer clearly shows the benefit of increasing water permeability compared with a membrane whose pores are more tortuous. We also corroborated the effectiveness of MOF inclusion by varying its concentration, showing outstanding performance in water permeability compared with those of conventional and advanced thin-film composite membranes with high salt selectivity. This work presents a promising membrane configuration for further improving osmotic pressure by increasing the water flux.

On the way to achieve a practical lithium (Li) metal anode for next-generation batteries, the formation and accumulation of inactive “Dead Li” is an unavoidable issue. The accumulation of “Dead Li” leads to increased internal mass-transfer resistance which seriously deteriorates the performance of Li metal batteries during long-term cycling. In this study, by accommodating Li metal into a copper oxide coated carbon scroll host with a vertically aligned framework which possesses a unique low-tortuosity structure, the cycling stability of the Li anode can be significantly improved. It is demonstrated that the mass-transfer resistance and the concentration polarization near the Li metal surface can be greatly alleviated by using this low-tortuosity anode structure design. “Dead Li” that is formed on the electrode surface can automatically fall into the inner tunnel of the carbon host, endowing the anode with the capability of “Dead Li” self-cleaning. As a result, our new Li electrode can remain electrochemically active even after 1000 h in a symmetric cell measurement from 1 mA cm−2 to 1 mA h for 500 cycles. The as-reported structure design of the Li anode in this work is compatible with most of the modification technologies that have been applied to conventional Li foil electrodes, providing this new Li anode with a great potential to be applied in subsequent Li anode studies.

The separation process of oily water using membranes has attracted the attention of researchers and engineers. The greater problem in the use of membrane separation process is the reduction in permeate flux due to clogged pores by oil deposition inside the membrane or by the effect of the concentration polarization. For this purpose, a theoretical study of a water/oil separation module was performed. This device consists of a tubular ceramic membrane provided with a rectangular inlet section. Numerical simulations were performed using Ansys CFX software to solve the mass and momentum conservation equations in the fluid and porous domains. Here was adopted the RNG k-e turbulence model. The effect of the membrane porosity and the inlet velocity of the fluid mixture on the two-phase flow behavior inside the separation module were evaluated. Results of the volumetric fraction, velocity and pressure fields of the oil and water phases are presented and analyzed. The results indicate a higher oil concentration within the membrane for the cases of higher porosity, and that the inlet fluid mixture velocity does not substantially affect the velocity profile within the separation module. It is found that the maximum separation efficiency of the module was obtained with feed velocity of 40 m/s and membrane porosity of 0.44.

The article presents the results of a study of mass transfer in the process of electrochemical extraction of iron, magnesium and manganese ions from technological solutions. Mathematical expressions are obtained, and numerical values of empirical coefficients are determined for theoretical calculation of specific outflow, retention coefficient, and average mass transfer coefficients of the electrochemical membrane process of separation of technological solutions. The dependence of concentration polarization on solution flow rate, pressure gradient, and concentration is analyzed.

Purification by using membrane technology has been recently considered as an alternative method to the conventional purification of crude vegetable oil. Although there are studies regarding the application of membrane technology on the purification of crude vegetable oil, the research on the separation process performance by considering transport models is scarce. Therefore, in this work, an investigation on the performance of organic solvent nanofiltration (OSN) for palm oil and solvent mixtures was carried out. In order to describe and predict the membrane separation performance, the integration of membrane transport model with experimental data is required. Parameter estimation of transport model parameters was conducted to correlate a chosen transport model to the experimental data. In this research, the effect of concentration polarization was also included in the mass transfer of triglycerides, whereby a combined film theory/ solution diffusion transport model was employed. The results revealed that the permeation flux of palm oil and acetone mixtures in SolSep NF 030,306 nanofiltration membrane increased with increasing stirring speed but decreased with increasing feed viscosity. The rejection of triglyceride, on the other hand, increased with increasing feed concentration, however, the rejection did not show any significant trending with the change in operating pressure. This study served as the first attempt to investigate the performance of organic solvent nanofiltration of palm oil by using a solvent resistant membrane through both experiments and membrane transport modeling.

Bipolar membranes (BPMs) have the potential to become critical components in electrochemical devices for a variety of electrolysis and electrosynthesis applications. Because they can operate under large pH gradients, BPMs enable favorable environments for electrocatalysis at the individual electrodes. Critical to the implementation of BPMs in these devices is understanding the kinetics of water dissociation that occurs within the BPM as well as the co- and counter-ion crossover through the BPM, which both present significant obstacles to developing efficient and stable BPM-electrolyzers. In this study, a continuum model of multi-ion transport in a BPM is developed and fit to experimental data. Specifically, concentration profiles are determined for all ionic species, and the importance of a water-dissociation catalyst is demonstrated. The model describes internal concentration polarization and co- and counter-ion crossover in BPMs, determining the mode of transport for ions within the BPM and revealing the significance of salt-ion crossover when operated with pH gradients relevant to electrolysis and electrosynthesis. Finally, a sensitivity analysis reveals that the performance and lifetime of BPMs can be improved substantially by using of thinner dissociation catalysts, managing water transport, modulating the thickness of the individual layers in the BPM to control salt-ion crossover, and increasing the ion-exchange capacity of the ion-exchange layers in order to amplify the water-dissociation kinetics at the interface.

Membrane technology has been gradually used as an alternative to the conventional separation and purification method in various industries. In recent years, solvent-stable nanofiltration or organic solvent nanofiltration has becoming practicable through the development of solvent-stable commercial polymeric membranes. Organic solvent nanofiltration has a great potential to replace the conventional energy-demanding process such as distillation due to its ability of separating organic solvents and solutes on a molecular level without phase change and operation at relatively mild temperature. Predicting the performance of such membrane separations is crucial in the process design. Important performance indicator such as the permeate flux and the rejections are strongly related to the fluid dynamics, mass transfer and solute-solvent-membrane interactions. The aim of this paper is to review and assess the transport models of solute and solvent transport relevant to organic solvent nanofiltration. The link between concentration polarization and the hydrodynamics in various configurations are discussed. The effects of process variables on membrane performance and solute-solvent membrane interactions are also reviewed.

Forward osmosis (FO) was investigated for treating an acid gold-mining effluent. Draw solution reconcentration by reverse osmosis (RO) was simulated and the FO-RO system economically evaluated. FO ...

This paper presents a novel approach using sulfonated polyethersulfone/zeolitic imidazolate framework (SPES/ZIF-8) porous nanocomposite substrate to enhance the salt rejection and water flux of forward osmosis (FO) membrane. The effect of SPES/ZIF-8 substrate on FO membrane properties containing morphologies, hydrophilicity, water permeability and salt rejection were investigated and completely discussed. Based on the obtained results, the selectivity and permeability of thin-film nanocomposite (TFN) FO membranes can be improved simultaneously through adjusting the both hydrophilic and hydrophobic characteristics. But these two results, is achieved in two different processes and with reverse impacts. After the sulfonation process and using the more hydrophilic polymer (SPES) instead of the neat PES, the porosity and consequently the water flux was increased. Because of more hydrophilicity of SPES which reduces the cross-linking degree of the corresponding polyamide (PA) layer, the salt rejection was reduced. In contrast, after the incorporation of ZIF-8 into the SPES substrate, the salt rejection was increased due to the hydrophobic nature of these nanoparticles (NPs). In terms of both salt rejection and water flux, the sulfonated TFN membrane with 0.5% ZIF-8 NPs (TFN-S0.5 membrane) showed the improved results comparing with the bare Thin-film composite (TFC) membrane. Furthermore, the best result for the ratio of reverse salt flux to water flux (Js/Jw) as the selectivity parameter, was about 0.16 g/L using 10 mM and 2 M NaCl solutions as the feed solution (FS) and the draw solution (DS), respectively, in the FO experiment. Also, the structural parameter (S) which is believed to have a strong relationship with the internal concentration polarization (ICP), was decreased to 0.39 nm as the best result, after modification of FO membrane.

Colloid-enhanced ultrafiltration (CEUF), i.e., micellar-enhanced ultrafiltration (MEUF) and polymer-enhanced ultrafiltration (PEUF), was investigated to remove sulfate ions from aqueous solution in batch experiments, using cetyltrimethylammonium (CTAB) and poly(diallydimethylammonium chloride) (PDADMAC) as colloids, respectively. Ultrafiltration performance was evaluated under different initial concentrations of sulfate (0–20 mM) and CTAB/PDADMAC (0–100 mM). The highest retention rate (> 99%) was found in dilute sulfate solutions. At high sulfate concentrations (e.g., 10 mM), a dosage of 50 mM CTAB or PDADMAC can retain approximately 90% of sulfate ions. Though concentration polarization behavior was observed, membrane characterization indicated that the fouling was reversible and membranes can be reused. Furthermore, adsorption equilibrium and kinetics studies show that Freundlich isotherm and pseudo-second-order kinetics can describe the sulfate-colloid interaction, indicating that the surface of absorbents are heterogeneous and the rate-controlling step is chemisorption. Both MEUF and PEUF show potential as effective separation techniques in removing sulfate from aqueous solutions. Under the same conditions examined, PEUF shows advantages over MEUF in its higher retention at lower polymer-to-sulfate ratios, cleaner effluent, and higher adsorption capacity, but compromises on severer flux decline and a tendency of membrane fouling. To overcome this disadvantage, membranes with higher molecular weight cut-off can be used.

The incorporation of inorganic nanoparticles into thin film composite forward osmosis (TFC FO) membranes is an effective method to alleviate internal concentration polarization (ICP) and enhance the flux performance of the FO membrane. In this paper, synthetic hydrophilic rod-like porous nano-hydroxyapatites (PNHAs) were doped into polysulfone (PSf) casting solution to form support layer by phase inversion; further interfacial polymerization was carried out to prepare a high performance TFC FO membrane. The results showed that the incorporation of PNHAs not only improved the thickness, porosity, hydrophilicity, and connectivity of the support layer, but also enhanced the roughness of the active layer. The measured mass transfer parameters prove that these improvements were beneficial. Further FO experiments showed that when using deionized water as the feed solution and 1mol/L NaCl as the draw solution, TFN 0.75 showed higher water flux than TFC FO membrane in both AL-FS (18.5 vs 7.16 L/m2·h) and AL-DS (33.26 vs 9.93 L/m2·h) modes. Reverse salt flux had not increased significantly. At the same time, TFN 0.75 (697 μm vs 1,960 μm) showed the smallest structural parameter. This study shows that PNHA is a suitable nanomaterial for mitigating the ICP effect of FO membranes.

A model of the S-entropy production in a system with a membrane which separates non-electrolyte aqueous solutions was presented. The differences between fluxes in non-homogeneous and homogeneous conditions for volume and solute fluxes, respectively, are non-linear functions of the glucose osmotic pressure difference (OPD) in ranges dependent on the initial ethanol OPD. A decrease of ethanol OPD causes a shift of this range into the lower values of glucose OPD; this shift is also observed for negative values of glucose and ethanol OPDs. The coefficient of concentration polarization of the membrane as a function of glucose OPD has a sigmoidal shape. For suitably great negative values of glucose OPD this coefficient is very small, while for suitably high positive glucose OPD this coefficient is equal to 0.5. An increase of ethanol OPD at the initial moment causes a shift of this curve towards the direction of positive values of glucose OPD. In turn the S-entropy production in non-homogeneous conditions has low values for negative values of glucose OPD (convective range) while for suitably high positive glucose OPD it has greater values (diffusive and convective range). A change of ethanol OPD at the initial moment causes a shift of this curve along the horizontal axis.