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On the diffusive water transport through polyelectrolyte-based membranes

JOURNAL OF MEMBRANE SCIENCE LETTERS 2025年第1期5卷

作者： Mehlis, Jannik Wessling, Matthias Rhein Westfal TH Aachen Chem Proc Engn AVT CVT Forckenbeckstr 51 D-52074 Aachen Germany DWI Leibniz Inst Interact Mat eV Forckenbeckstr 50 D-52074 Aachen Germany

This study investigates water transport behavior through polyelectrolyte membranes under varying pressure gradients using non-equilibrium molecular dynamics (NEMD) simulations. While net water transport is achieved under a pressure gradient, there is also a significant back-diffusion component, challenging the assumption of unidirectional pore flow in such systems. The auto-correlation function of water molecules reveals that water associations are transient and only occur for short periods compared to the overall residence time within the membrane. The correlation of water associations and the water dynamics inside the membrane are not affected by varying pressure differences, which also favors the assumption of a diffusive transport mechanism rather than pore flow. Furthermore, our NEMD simulations provide a detailed analysis of the diffusion-related time lag, revealing an initial transient water transport response and a constant diffusive time lag for all pressure differences. These findings enhance our understanding of water transport mechanisms in membrane systems, underlining the validity of the solution-diffusion model for dense polymeric membranes. The methodology described can be applied to shed light on the discrimination between pore flow and solution-diffusion phenomena.

关键词： Water transport mechanisms Polyelectrolyte membrane solution-diffusion model Diffusive time lag Molecular Dynamics

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Application of the solution-diffusion model for the removal of atrazine using a nanofiltration membrane

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DESALINATION AND WATER TREATMENT 2013年第10-12期51卷 2244-2252页

作者： Hidalgo, A. M. Leon, G. Gomez, M. Murcia, M. D. Barbosa, D. S. Blanco, P. Univ Murcia Dept Ingn Quim Fac Quim Murcia Spain Univ Politecn Cartagena Dept Ingn Quim & Ambiental Murcia Spain

The solution-diffusion model was used to predict the behaviour of four nanofiltration membranes, two were made of polyamide (NF-99 and NF-97) and the other two were made of polypiperazineamide (DL and DK), when used for the removal of atrazine from aqueous solutions. The mass transfer model applied is very simple and its linearization facilitates rapid calculation of the relevant parameters. The two main parameters, permeate concentration and volumetric permeate flux, are obtained from three different coefficients: water permeability, A(w), solute permeability, B-s, and osmotic pressure coefficients, Psi. Good agreement between the experimental and the predicted atrazine concentrations was obtained for the NF-99, DL and DK membranes when the concentration was low. However, only the NF-99 membrane provided accurate values for the two main parameters in the whole range of concentrations studied, which suggests that the solution-diffusion model can only be applied to this membrane.

关键词： Atrazine Membrane process Nanofiltration solution-diffusion model

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Reverse osmosis and pervaporation of organic liquids using organosilica membranes: Performance analysis and predictions

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AICHE JOURNAL 2022年第4期68卷 e17585-e17585页

作者： Dong, Guanying Zhang, Yatao Sato, Takaaki Nagasawa, Hiroki Kanezashi, Masakoto Tsuru, Toshinori Zhengzhou Univ Sch Chem Engn Zhengzhou Peoples R China Hiroshima Univ Dept Chem Engn Hiroshima Japan

This study systematically investigated and modeled the organic solvent reverse osmosis (OSRO) and pervaporation (PV) performances of bis(triethoxysiyl)acetylene (BTESA)-derived microporous organosilica membranes with different microstructures and permeation properties. BTESA membranes calcined at a low temperature of 100 degrees C exhibited great promise for utility in the challenging OSRO separation of methanol/organic azeotropes such as methanol/toluene and methanol/methyl tert-butyl ether and demonstrated ultrahigh values for both permeating flux and rejection together with good operation stability. In addition, a generalized solution-diffusion model enabled a suitable description of the permeation behaviors of organic solvent molecules through the BTESA membranes irrespective of the use of either OSRO or PV modalities, which allowed us to predict the OSRO performance via PV, and vice versa.

关键词： methanol organic solvent reverse osmosis organosilica membranes pervaporation solution-diffusion model

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Nitrate removal studies on polyurea membrane using nanofiltration system - membrane characterization and model development

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CHEMICAL PRODUCT AND PROCESS modelING 2022年第1期17卷 81-99页

作者： Kancherla, Ravichand Kumar, Vadeghar Ramesh Reddy, Ginuga Prabhaker Sridhar, Sundergopal Indian Inst Chem Technol IICT Chem Engn Div Membrane Separat Grp Hyderabad 500007 India Osmania Univ Univ Coll Technol UCT Hyderabad 500007 India

Desalination of nitrates from brackish water is prominent in the coastal areas due to excessive disposal of pesticides by agricultural industries. Nowadays, membrane processes are growing tremendously for the desalination of brackish water. In this context, polyurea (PU) could be a useful membrane material for the treatment of brackish water. The present work deals with the removal of nitrates from synthetic water using PU membranes by nanofiltration (NF) process. Polyurea thin film composite (PU-TFC) membranes were prepared by interfacial polymerization followed by thermal crosslinking and characterized using Fourier transformed infrared spectral (FTIR), X-ray diffraction (XRD), scanning electron microscopy- energy dispersion X-ray spectroscopy (SEM-EDS), Atomic force microscopy (AFM), thermogravimetric (TGA), and universal testing machine (UTM) for structural analysis, crystallinity, morphological, compositional, thermal and mechanical properties, respectively. Experimental studies were conducted on an NF pilot plant by varying operating pressure from 2 to 10 bar and feed nitrate concentration from 60 to 200 mg/L for evaluating PU membrane performance. Experimental observations revealed a maximum water flux of 30.6 L/m(2) h and nitrate rejection of 97.2% at a pressure of 10 bar for feed containing 140 mg/L of nitrate. A mass transfer model was developed on the basis of solution-diffusion mechanism for a semi-batch NF process by considering cake enhanced concentration polarization model, for laminar flow with feed recycle, using a plate and frame membrane module. A generic semi-batch NF process model was integrated taking into account concentration polarization and fouling layer resistance. The integrated model was successfully compared with existing data in literature and could be used for process scale-up. Due to the merits of hydrophilicity, negative charge, high thermal and mechanical resistance, the PU membrane can be termed as a low cost, commercially viable

关键词： cake enhanced concentration polarization desalination nanofiltration process nitrate removal polyurea membrane solution-diffusion model

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Prediction of Flux and Rejection Coefficients in the Removal of Emerging Pollutants Using a Nanofiltration Membrane

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MEMBRANES 2023年第11期13卷 868-868页

作者： Hidalgo, Asuncion M. Gomez, Maria Murcia, Maria D. Gomez, Elisa Leon, Gerardo Alfaro, Irene Lee, Kueir-Rarn Univ Murcia Chem Engn Dept Campus Univ Espinardo Murcia 30100 Spain Polytech Univ Cartagena Chem & Environm Engn Dept Cartegena 30206 Spain

The removal of three emerging pollutants: carbamazepine, ketoprofen, and bisphenol A, has been studied using the nanofiltration flat sheet membrane NF99HF. The removal efficiencies of the membrane have been evaluated by two system characteristic parameters: permeate flux and rejection coefficient. The influence of two operating variables has been analysed: operating pressure and feed concentration. Before and after the tests with emerging pollutants, the membrane has been characterized by determining its water permeability coefficient and its magnesium chloride rejection coefficient to find out if the removal of emerging pollutants causes membrane fouling. The results show that operating pressure has significant separation effects, obtaining the highest efficiencies at a pressure of 20 bar for pollutant concentrations between 5 and 25 mg/L. Moreover, rejection of ketoprofen was found to be dependent on electrostatic repulsion, while rejection of bisphenol A was significantly affected by adsorption onto the membrane. Finally, the experimental data have been fitted to the solution diffusion model and to the simplified model of Spiegler-Kedem-Katchalsky to predict the behaviour of the nanofiltration membrane in the removal of the tested pollutants. Good agreement between the experimental and predicted carbamazepine and bisphenol A data has been obtained with each model, respectively.

关键词： nanofiltration membranes emerging pollutants carbamazepine ketoprofen bisphenol A solution-diffusion model Spiegler-Kedem-Katchalsky model

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Understanding butanol recovery and coupling effects in pervaporation of Acetone-Butanol-Ethanol (ABE) solutions: A modelling and experimental study

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JOURNAL OF MEMBRANE SCIENCE 2022年 658卷

作者： Mutto, Abeer Mahawer, Ketan Shukla, Anupam Gupta, Sharad Kumar Indian Inst Technol Delhi Dept Chem Engn Delhi 110016 India

The sustainable downstream recovery of bio-butanol from multicomponent fermentation broths through organophilic pervaporation is still challenged, in part, by a limited knowledge on the effect of by-products ethanol and acetone on final butanol recovery. This study therefore involves an experimental and theoretical inquisition on extraction of butanol and coupling effects involved between the various components. A commercial polydimethylsiloxane membrane was used for pervaporation of binary and ternary model solutions. Modified solution-diffusion based models were then customized to emulate temperature and concentration dependence of permeation. Membrane performance and coupling were found to be functions of the concentration of both organic components involved as well as temperature of the feed. The membrane was observed to be most intrinsically selective towards butanol in all systems. In ternary mixtures, the presence of second organic component positively enhanced coupling effects in favor of butanol recovery but lead to a decreased membrane plasticization by butanol itself. Ultimately permeance based coupling factors revealed that membrane permselectivity towards butanol was best benefited by coupling at lower butanol to ethanol/acetone concentration ratios in feed. In contrast, minimal coupling was experienced at equimolar conditions and multicomponent pervaporation in such cases could be satisfactorily modelled as binary mixture separation.

关键词： Pervaporation Acetone-butanol-ethanol (ABE) Coupling effects Plasticization coefficients solution-diffusion model

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Investigation of mass transport processes in a microstructured membrane reactor for the direct synthesis of hydrogen peroxide

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CHEMICAL ENGINEERING SCIENCE 2022年第PartB期248卷 117145-117145页

作者： Trinkies, Laura L. Duell, Andrea Zhang, Jinju Urban, Sebastian Deschner, Benedikt J. Kraut, Manfred Ladewig, Bradley P. Weltin, Andreas Kieninger, Jochen Dittmeyer, Roland Karlsruhe Inst Technol Inst Micro Proc Engn IMVT D-76344 Eggenstein Leopoldshafen Germany Univ Freiburg IMTEK Lab Sensors Dept Microsyst Engn D-79110 Freiburg Germany Karlsruhe Inst Technol Inst Catalysis Res & Technol IKFT D-76344 Eggenstein Leopoldshafen Germany Inst Chem Technol & Polymer Chem ITCP D-76131 Karlsruhe Germany

Microstructured membrane reactors present a promising approach to master the productivity and safety challenges during the direct synthesis of hydrogen peroxide. However, various mass transport processes occur in this complex system. In order to gain a deeper understanding of these processes, the saturation and desaturation behaviour of the liquid reaction medium with the gaseous reactants is investigated experimentally to examine possible cross-contamination. Moreover, the employed PDMS membrane's permeances to hydrogen and oxygen are researched at different pressures, by using a variable-pres sure/constant-volume setup for the behaviour at ambient pressure and a constant-pressure/variable-vo lume setup for the behaviour at elevated pressures. A mathematical model in MATLAB is applied to simulate the results. It is shown that a certain desaturation of the gasses through the membrane occurs, and the results are underlined by the modelled ones using a solution-diffusion model in MATLAB. Thus a constant flushing of the gas channels of the reactor is required for safety reasons. Moreover, the measured permeance values indicate that the species transport is mainly limited by the diffusion in the liquid phase and not the membrane resistance. CO 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://***/licenses/by/4.0/).

关键词： Membrane permeance PDMS Cross-contamination solution-diffusion model Microreactor

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Supercritical CO2 permeation through dense commercial polymeric membranes: Permeability measurements and influence of pressure

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JOURNAL OF SUPERCRITICAL FLUIDS 2022年第0期188卷

作者： Chabni, Dihia Karakache, Sabrina Condoret, Jean-Stephane Camy, Severine Remigy, Jean-Christophe Univ Toulouse Lab Genie Chim CNRS INPTUPS Toulouse France

In the food industry, supercritical CO2 (sc-CO2) is widely used as an extraction solvent, particularly for the extraction of lipids from seeds. After the extraction, the decompression is usually used to recover the products. Afterwards, the recompression for CO2 recycling is highly energy consuming and this handicaps industrial development when medium to low added-value post-extraction products are considered. Recovery of solutes using membrane technology is an interesting alternative for the regeneration of CO2 loaded with oil. The suitable membrane must have a high permeability towards CO2 as reasonable filtration area is needed. In this work, we have studied the CO2 membrane permeability of two different dense polymeric membranes, AG aromatic polyamide reverse osmosis membrane and PuraMem (TM) silicone nanofiltration membrane. It was considered that the pure sc-CO2 permeation is governed by the solution-diffusion model, which explain the observed permeability changes as a function of CO2 viscosity and fugacity (i.e. pressure) and the polymer properties as chemical composition and structure. Indeed, it was observed that the permeability increased with pressure to reach a maximum value at a permeate pressure of 180 bar (17.3 +/- 0.9 kg/(h.m(2).bar)), and then decreased in the case of a crosslinked polymer (AG membrane). While, for a slightly crosslinked polymer (PuraMem (TM) membrane), the permeability was found much higher and it is about 751.6 +/- 26.4 kg/(h.m(2).bar) at a permeate pressure of 160 bar.

关键词： Supercritical CO2 Polymeric commercial membranes solution-diffusion model Permeability

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Advanced methods for analysis of mixed gas diffusion in polymeric membranes

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JOURNAL OF MEMBRANE SCIENCE 2022年第0期648卷 120356-120356页

作者： Monteleone, Marcello Fuoco, Alessio Esposito, Elisa Rose, Ian Chen, Jie Comesana-Gandara, Bibiana Bezzu, C. Grazia Carta, Mariolino McKeown, Neil G. Shalygin, Maxim V. Teplyakov, Vladimir Jansen, Johannes Carolus Natl Res Council Italy CNR ITM Inst Membrane Technol Via P Bucci 17-C I-87036 Arcavacata Di Rende CS Italy Univ Edinburgh Sch Chem EaStCHEM Joseph Black BldgDavid Brewster Rd Edinburgh EH9 3FJ Midlothian Scotland Cardiff Univ Sch Chem Cardiff CF10 3AT Wales Swansea Univ Coll Sci Dept Chem Swansea SA2 8PP W Glam Wales Russian Acad Sci TIPS RAS AV Topchiev Inst Petrochem Synth Leninsky Prospect 29 Moscow 119991 Russia

The rapid advancement of membrane gas separation processes has spurred the development of new and more efficient membrane materials, including polymers of intrinsic microporosity. The full exploitation of such materials requires thorough understanding of their transport properties, which in turn necessitates the use of powerful and reliable characterization methods. Most methods focus on the permeability, diffusivity and solubility of single gases or only the permeability of mixed gases, while studies reporting the diffusion and solubility of gas mixtures are extremely rare. In this paper we report the use of a mass-spectrometric residual gas analyser to follow the transient phase of mixed gas transport through a benzotriptycene-based ultrapermeable polymer of intrinsic microporosity (PIM-DTFM-BTrip) and a polydimethylsiloxane (PDMS) membrane for comparison, via the continuous online analysis of the permeate. Computational analysis of the entire permeation curve allows the calculation of the mixed gas diffusion coefficients for all individual gases present in the mixture and the identification of non-Fickian diffusion or other anomalous behaviour. The mixed gas transport parameters were analysed by three different approaches (integral, differential and pulse signal), and compared with the results of the 'classical' time lag method for single gases. PDMS shows very similar results in all cases, while the transport in the PIM gives different results depending on the specific method and instrument used. This comparative study provides deep insight into the strengths and limitations of the different instruments and data elaboration methods to characterize the transport in rubbery and high free volume glassy membranes with fundamentally different properties and will be of help in the development of novel membrane materials.

关键词： Gas separation membrane solution-diffusion model Mixed gas diffusion Time lag Transport properties Mathematics of diffusion

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Fast surface crosslinking ceramic hollow fiber pervaporation composite membrane with outstanding separation performance for isopropanol dehydration

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SEPARATION AND PURIFICATION TECHNOLOGY 2020年 234卷 116116-000页

作者： Zhang, Xin Li, Meng-Ping Huang, Zhi-Hao Zhang, Hao Liu, Wei-Liang Xu, Xin-Ru Ma, Xiao-Hua Xu, Zhen-Liang East China Univ Sci & Technol Chem Engn Res Ctr Membrane Sci & Engn R&D Lab Shanghai Key Lab Multiphase Mat Chem Engn 130 Meilong Rd Shanghai 200237 Peoples R China

A facile fast surface crosslinking method was adopted to fabricate ceramic hollow fiber composite membranes with a thin separation layer for outstanding pervaporation (PV) performance. The morphologies, surface chemical compositions and hydrophilicity of the chitosan (CS)/ceramic hollow fiber composite membranes were characterized by field emission scanning electron microscopy (SEM), X-ray photoelectron analysis (XPS), and water contact angle (CA), respectively. The influences of CS concentration, feed composition and temperature on the membrane performances were investigated systematically. The operation time of the surface crosslinking process was several minutes (i.e., 4 min). The thickness of the separation layer of the obtained composite membranes ranged from 322 to 1414 nm, exhibiting excellent separation performance. The Arrhenius active energy (E-J and E-D) and the diffusion coefficient (D-w and D-IPA) were calculated to theoretically analyze the membrane separation process. The highest PV separation index (PSI) value was 8.2 x 10(6), indicating that the obtained membranes possessed enormous potential in IPA dehydration.

关键词： Fast surface crosslinking Hollow fiber composite membrane lsopropanol dehydration Arrhenius equation solution-diffusion model

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