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20 pages, 3230 KiB

Open AccessArticle

Modeling of Integrated Hollow-Fiber Solar-Powered VMD Modules for Desalination for a Better Understanding and Management of Heat Flows

by Gina Alfonso, Stéphanie Laborie and Corinne Cabassud

Membranes 2024, 14(2), 50; https://doi.org/10.3390/membranes14020050 - 11 Feb 2024

Viewed by 1715

Abstract

The direct integration of membrane distillation and solar energy collection in a single module is a promising technology for autonomous seawater desalination in remote regions; however, the modeling and design of such modules are challenging because of the coupling of the radial and [...] Read more.

The direct integration of membrane distillation and solar energy collection in a single module is a promising technology for autonomous seawater desalination in remote regions; however, the modeling and design of such modules are challenging because of the coupling of the radial and longitudinal heat and mass transfers. In a previous study, we provided as a first modeling approach a hollow fiber solar collector vacuum membrane distillation (VMD) module, considering a constant temperature at the shell side and a pure water feed. Here, a full model is developed to describe the coupled effects of the solar collector and a hollow fiber VMD module operating in an outside/in mode with saline water. The model considers all the main phenomena (membrane distillation, temperature and concentration polarization, absorption of solar radiation and energy balances over the solar collector, radial and longitudinal heat and mass transfer, seawater properties, and more than 30 variables). Applied to simulate the behavior of a semi-industrial-scale module, it allows the influence of solar radiation on the performance/limits of the integrated module to be discussed based on the radial and longitudinal profiles and heat flows. The model can be used to identify key points in the module design to better utilize solar radiation and manage heat flows. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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21 pages, 5655 KiB

Open AccessArticle

Application of Machine Learning to Characterize the Permeate Quality in Pilot-Scale Vacuum-Assisted Air Gap Membrane Distillation Operation

by Isabel Requena, Juan Antonio Andrés-Mañas, Juan Diego Gil and Guillermo Zaragoza

Membranes 2023, 13(11), 857; https://doi.org/10.3390/membranes13110857 - 26 Oct 2023

Viewed by 1819

Abstract

Membrane distillation (MD) is a thermal desalination technique proposed for the valorization of residual brines that other operations such as reverse osmosis cannot treat. Previous studies have shown that vacuum-assisted air gap (V-AGMD) operation in commercial multi-envelope modules improves the performance of MD [...] Read more.

Membrane distillation (MD) is a thermal desalination technique proposed for the valorization of residual brines that other operations such as reverse osmosis cannot treat. Previous studies have shown that vacuum-assisted air gap (V-AGMD) operation in commercial multi-envelope modules improves the performance of MD noticeably. However, the permeate quality at pilot scale has not been thoroughly characterized so far. The aim of this study is, therefore, to assess and model the effect of the main operating conditions (feed flow rate, inlet temperatures, and feed salinity) on the permeate quality. Results from different steady-state experiments allowed to estimate descriptive metrics such as the salt rejection factor (SRF) and the membrane leak ratio (MLR). Given their non-linear behavior, these metrics were subsequently modeled using artificial neural networks (ANN) to estimate the permeate quality in the whole scope of operating conditions. Acceptable SRF results with MLR values lower than 0.2% confirmed the validity of MD as an operation for the treatment of concentrated brines, although the salinity of the resulting permeate does not comply in all cases with that permitted for human consumption. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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32 pages, 6517 KiB

Open AccessArticle

Review and Analysis of Heat Transfer in Spacer-Filled Channels of Membrane Distillation Systems

by Sebastian Schilling and Heike Glade

Membranes 2023, 13(10), 842; https://doi.org/10.3390/membranes13100842 - 22 Oct 2023

Cited by 1 | Viewed by 1660

Abstract

Membrane distillation (MD) is an attractive process for the concentration of seawater brines. Modelling and simulation of membrane distillation processes requires a better knowledge of the heat transfer coefficients in spacer-filled channels which are usually determined by applying empirical correlations for the Nusselt [...] Read more.

Membrane distillation (MD) is an attractive process for the concentration of seawater brines. Modelling and simulation of membrane distillation processes requires a better knowledge of the heat transfer coefficients in spacer-filled channels which are usually determined by applying empirical correlations for the Nusselt number. In this study, first, a comprehensive literature review on heat transfer correlations was conducted. It was found that the empirical correlations often used for MD simulation result in strongly varying Nusselt numbers that differ by up to an order of magnitude at low Reynolds numbers. Then, heat transfer in spacer-filled channels was investigated experimentally in a membrane distillation system using an aluminum plate instead of a flat-sheet membrane. Numerous tests were carried out with sodium chloride solutions in a wide range of salinities, between 1 g/kg and 95 g/kg, and temperatures, between 30 °C and 80 °C, yielding high heat transfer coefficients in a range of 1500 to 8300 W/(m²K) at relatively low Reynolds numbers, between 100 and 1500, clearly showing the influence of the spacers on heat transfer. A new empirical Nusselt correlation (

N u = 0.158 {R e}^{0.652} {P r}^{0.277}

) was derived which represents the experimental data with a deviation of 10% and is valid for

100 < R e < 1500

and

2 < P r < 7

. Computational fluid dynamics simulations were performed to analyze the variations of the fluid properties across the boundary layer due to temperature differences. The simulations showed only minor deviations of the heat transfer coefficients in the hot and cold fluid channels for small driving temperature differences. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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18 pages, 2146 KiB

Open AccessEditor’s ChoiceArticle

Polymeric Inclusion Membranes Based on Ionic Liquids for Selective Separation of Metal Ions

by Adrián Hernández-Fernández, Eduardo Iniesta-López, Anahí Ginestá-Anzola, Yolanda Garrido, Antonia Pérez de los Ríos, Joaquín Quesada-Medina and Francisco José Hernández-Fernández

Membranes 2023, 13(9), 795; https://doi.org/10.3390/membranes13090795 - 13 Sep 2023

Cited by 3 | Viewed by 2063

Abstract

In this work, poly(vinyl chloride)-based polymeric ionic liquid inclusion membranes were used in the selective separation of Fe(III), Zn(II), Cd(II), and Cu(II) from hydrochloride aqueous solutions. The ionic liquids under study were 1-octyl-3-methylimidazolium hexafluorophosphate, [omim⁺][PF₆⁻] and methyl trioctyl [...] Read more.

In this work, poly(vinyl chloride)-based polymeric ionic liquid inclusion membranes were used in the selective separation of Fe(III), Zn(II), Cd(II), and Cu(II) from hydrochloride aqueous solutions. The ionic liquids under study were 1-octyl-3-methylimidazolium hexafluorophosphate, [omim⁺][PF₆⁻] and methyl trioctyl ammonium chloride, [MTOA⁺][Cl⁻]. For this purpose, stability studies of different IL/base polymer compositions against aqueous phases were carried out. Among all polymer inclusion membranes studied, [omim⁺][PF₆⁻]/PVC membranes at a ratio of 30/70 and [MTOA⁺][Cl⁻]/PVC membranes at a ratio of 70/30 were able to retain up to 82% and 48% of the weight of the initial ionic liquid, respectively, after being exposed to a solution of metal ions in 1 M HCl for 2048 h (85 days). It was found that polymer inclusion membranes based on the ionic liquid methyl trioctyl ammonium chloride allowed the selective separation of Zn(II)/Cu(II) and Zn(II)/Fe(III) mixtures with separation factors of 1996, 606 and, to a lesser extent but also satisfactorily, Cd(II)/Cu(II) mixtures, with a separation factor of 112. Therefore, selecting the appropriate ionic liquid/base polymer mixture makes it possible to create polymeric inclusion membranes capable of selectively separating target metal ions. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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14 pages, 1423 KiB

Open AccessArticle

Iron Control in Liquid Effluents: Pseudo-Emulsion Based Hollow Fiber Membrane with Strip Dispersion Technology with Pseudo-Protic Ionic Liquid (RNH₃⁺HSO₄⁻) as Mobile Carrier

by Francisco Jose Alguacil and Jose Ignacio Robla

Membranes 2023, 13(8), 723; https://doi.org/10.3390/membranes13080723 - 8 Aug 2023

Cited by 2 | Viewed by 1346

Abstract

The transport of iron(III) from aqueous solutions through pseudo-emulsion-based hollow fiber with strip dispersion (PEHFSD) was investigated using a microporous hydrophobic hollow fiber membrane module. The pseudo-protic ionic liquid RNH₃HSO₄⁻ dissolved in Solvesso 100 was used as the carrier [...] Read more.

The transport of iron(III) from aqueous solutions through pseudo-emulsion-based hollow fiber with strip dispersion (PEHFSD) was investigated using a microporous hydrophobic hollow fiber membrane module. The pseudo-protic ionic liquid RNH₃HSO₄⁻ dissolved in Solvesso 100 was used as the carrier phase. This pseudo-protic ionic liquid was generated by the reaction of the primary amine Primene JMT (RNH₂) with sulphuric acid. The aqueous feed phase (3000 cm³) containing iron(III) was passed through the tube side of the fiber, and the pseudo-emulsion phase of the carrier phase (400 cm³) and sulphuric acid (400 cm³) were circulated through the shell side in counter-current operational mode, using a single hollow fiber module for non-dispersive extraction and stripping. In the operation, the stripping solution (sulphuric acid) was dispersed into the organic membrane phase in a tank with a mixing arrangement (a four-blade impeller stirrer) designed to provide strip dispersion. This dispersed phase was continuously circulated from the tank to the membrane module in order to provide a constant supply of the organic solution to the fiber pores. Different hydrodynamic and chemical parameters, such as feed (75–400 cm³/min) and pseudo-emulsion phases (50–100 cm³/min) flows, sulphuric acid concentration in the feed and stripping phases (0.01–0.5 M and 0.5–3 M, respectively), metal concentration (0.01–1 g/L) in the feed phase, and PPILL concentration (0.027–0.81 M) in the carrier phase, were investigated. From the experimental data, different diffusional parameters were estimated, concluding that the resistance due to the feed phase was not the rate-controlling step of the overall iron(III) transport process. It was possible to concentrate iron(III) in the strip phase using this smart PEHFSD technology. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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29 pages, 11650 KiB

Open AccessArticle

Modeling and Optimal Operating Conditions of Hollow Fiber Membrane for CO₂/CH₄ Separation

by Dheyaa J. Jasim, Thamer J. Mohammed, Hamed N. Harharah, Ramzi H. Harharah, Abdelfattah Amari and Mohammed F. Abid

Membranes 2023, 13(6), 557; https://doi.org/10.3390/membranes13060557 - 29 May 2023

Cited by 8 | Viewed by 2610

Abstract

In this work, the capture of carbon dioxide using a dense hollow fiber membrane was studied experimentally and theoretically. The factors affecting the flux and recovery of carbon dioxide were studied using a lab-scale system. Experiments were conducted using a mixture of methane [...] Read more.

In this work, the capture of carbon dioxide using a dense hollow fiber membrane was studied experimentally and theoretically. The factors affecting the flux and recovery of carbon dioxide were studied using a lab-scale system. Experiments were conducted using a mixture of methane and carbon dioxide to simulate natural gas. The effect of changing the CO₂ concentration from 2 to 10 mol%, the feed pressure from 2.5 to 7.5 bar, and the feed temperature from 20 to 40 °C, was investigated. Depending on the solution diffusion mechanism, coupled with the Dual sorption model, a comprehensive model was implemented to predict the CO₂ flux through the membrane, based on resistance in the series model. Subsequently, a 2D axisymmetric model of a multilayer HFM was proposed to simulate the axial and radial diffusion of carbon dioxide in a membrane. In the three domains of fiber, the CFD technique was used to solve the equations for the transfer of momentum and mass transfer by using the COMSOL 5.6. Modeling results were validated with 27 experiments, and there was a good agreement between the simulation results and the experimental data. The experimental results show the effect of operational factors, such as the fact that temperature was directly on both gas diffusivity and mass transfer coefficient. Meanwhile, the effect of pressure was exactly the opposite, and the concentration of CO₂ had almost no effect on both the diffusivity and the mass transfer coefficient. In addition, the CO₂ recovery changed from 9% at a pressure equal to 2.5 bar, temperature equal to 20 °C, and a concentration of CO₂ equal to 2 mol%, to 30.3% at a pressure equal to 7.5 bar, temperature equal to 30 °C, and concentration of CO₂ equal 10 mol%; these conditions are the optimal operating point. The results also manifested that the operational factors that directly affect the flux are pressure and CO₂ concentration, while there was no clear effect of temperature. This modeling offers valuable data about the feasibility studies and economic evaluation of a gas separation unit operation as a helpful unit in the industry. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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Review

Jump to: Research

21 pages, 1633 KiB

Open AccessEditor’s ChoiceReview

Simultaneous Wastewater Treatment and Resources Recovery by Forward Osmosis Coupled with Microbial Fuel Cell: A Review

by Hengliang Zhang, Liang Duan, Shilong Li, Qiusheng Gao, Mingyue Li, Fei Xing and Yang Zhao

Membranes 2024, 14(2), 29; https://doi.org/10.3390/membranes14020029 - 23 Jan 2024

Cited by 6 | Viewed by 2598

Abstract

Osmotic microbial fuel cells (OsMFCs) with the abilities to simultaneously treat wastewater, produce clean water, and electricity provided a novel approach for the application of microbial fuel cell (MFC) and forward osmosis (FO). This synergistic merging of functions significantly improved the performances of [...] Read more.

Osmotic microbial fuel cells (OsMFCs) with the abilities to simultaneously treat wastewater, produce clean water, and electricity provided a novel approach for the application of microbial fuel cell (MFC) and forward osmosis (FO). This synergistic merging of functions significantly improved the performances of OsMFCs. Nonetheless, despite their promising potential, OsMFCs currently receive inadequate attention in wastewater treatment, water reclamation, and energy recovery. In this review, we delved into the cooperation mechanisms between the MFC and the FO. MFC facilitates the FO process by promoting water flux, reducing reverse solute flux (RSF), and degrading contaminants in the feed solution (FS). Moreover, the water flux based on the FO principle contributed to MFC’s electricity generation capability. Furthermore, we summarized the potential roles of OsMFCs in resource recovery, including nutrient, energy, and water recovery, and identified the key factors, such as configurations, FO membranes, and draw solutions (DS). We prospected the practical applications of OsMFCs in the future, including their capabilities to remove emerging pollutants. Finally, we also highlighted the existing challenges in membrane fouling, system expansion, and RSF. We hope this review serves as a useful guide for the practical implementation of OsMFCs. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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27 pages, 5353 KiB

Open AccessEditor’s ChoiceReview

Membrane-Based Technologies for Post-Combustion CO₂ Capture from Flue Gases: Recent Progress in Commonly Employed Membrane Materials

by Petros Gkotsis, Efrosini Peleka and Anastasios Zouboulis

Membranes 2023, 13(12), 898; https://doi.org/10.3390/membranes13120898 - 2 Dec 2023

Cited by 12 | Viewed by 10928

Abstract

Carbon dioxide (CO₂), which results from fossil fuel combustion and industrial processes, accounts for a substantial part of the total anthropogenic greenhouse gases (GHGs). As a result, several carbon capture, utilization and storage (CCUS) technologies have been developed during the last [...] Read more.

Carbon dioxide (CO₂), which results from fossil fuel combustion and industrial processes, accounts for a substantial part of the total anthropogenic greenhouse gases (GHGs). As a result, several carbon capture, utilization and storage (CCUS) technologies have been developed during the last decade. Chemical absorption, adsorption, cryogenic separation and membrane separation are the most widely used post-combustion CO₂ capture technologies. This study reviews post-combustion CO₂ capture technologies and the latest progress in membrane processes for CO₂ separation. More specifically, the objective of the present work is to present the state of the art of membrane-based technologies for CO₂ capture from flue gases and focuses mainly on recent advancements in commonly employed membrane materials. These materials are utilized for the fabrication and application of novel composite membranes or mixed-matrix membranes (MMMs), which present improved intrinsic and surface characteristics and, thus, can achieve high selectivity and permeability. Recent progress is described regarding the utilization of metal–organic frameworks (MOFs), carbon molecular sieves (CMSs), nanocomposite membranes, ionic liquid (IL)-based membranes and facilitated transport membranes (FTMs), which comprise MMMs. The most significant challenges and future prospects of implementing membrane technologies for CO₂ capture are also presented. Full article

(This article belongs to the Special Issue Advances in Modeling, Control, and Optimization of Membrane Distillation and Membrane Separation Processes)

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