Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.4
4.2
Journals
Membranes
Special Issues
Theoretical and Experimental Investigation of the Mass and Heat Transfers...
share announcement

Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Membrane Processing and Engineering".

Deadline for manuscript submissions: closed (31 May 2022) | Viewed by 59931

Special Issue Editors

Dr. Jianhua Zhang

E-Mail Website
Guest Editor
Institute for Sustainable Industries & Liveable Cities, Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia
Interests: membrane distillation; wastewater treatment; desalination; advanced oxidation; membrane filtration; NF; RO
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Ranil Wickramasinghe

E-Mail Website
Guest Editor
Ralph E Martin Department of Chemical Engineering, and Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
Interests: water treatment; biopurification; membrane; virus filtration; electrocoagulation
Special Issues, Collections and Topics in MDPI journals
Dr. Hongge Guo

E-Mail Website
Guest Editor
Qilu University of Technology, Jinan 250353, China
Interests: preparation and analysis of the structure and properties of gas transimission film; mass transfer, such as heat, oxygen, water vapor, aroma, and ethylene gas of multilayer composite film; modified atmosphere packaging and moisture-proof packaging for products

Special Issue Information

Dear Colleagues,

Membrane separation technology has been widely used in gas and liquid separation processes. It has the advantages of controllable selectivity, compact structure, and low ecological footprint. Depending on the characteristics of the membrane, it can be used to separate different phases such as solid from liquid or gas, solvent from solute, and different ions in the same phase. The selectivity or rejection of targeted components can rely on size exclusion, phase change, charge, etc. The active layer of the membrane can be a single material, composite materials or even formed during treatment, such as a membrane biological reactor. Various driving forces are involved in the mass transfer, such as the concentration gradient in forward osmosis, the electric potential difference in electrodialysis, the vapor pressure difference in the membrane distillation, and the pressure difference in filtration, reverse osmosis, and nanofiltration processes. Maximizing the mass productivity per unit driving force applied is preferred, since it will minimize the required membrane material or total footprint and energy input for the same treatment capacity. Therefore, it is critical to understand the factors or principles limiting or enhancing the transfer phenomena.

This Special Issue on “Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes” will bring together articles on studies of the mass and heat transfer phenomena/principles during membrane separation. We are requesting articles on all aspects of membrane separation processes, including manuscripts on literature reviews and research on membrane characterization, membrane fouling, membrane fabrication, and modeling for heat and mass transfer.

Dr. Jianhua Zhang
Prof. Dr. Ranil Wickramasinghe
Dr. Hongge Guo
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Membrane
  • Separation
  • Mass transfer
  • Heat transfer
  • Fouling
  • Selectivity
  • Retention

Published Papers (17 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

18 pages, 7604 KiB  
Article
Analysis and Experimental Study on Water Vapor Partial Pressure in the Membrane Distillation Process
by Zanshe Wang, Zhaoying Jia, Ran Li, Qi Gao and Zhaolin Gu
Membranes 2022, 12(8), 802; https://doi.org/10.3390/membranes12080802 - 19 Aug 2022
Cited by 4 | Viewed by 2028
Abstract
In membrane distillation, the vapor pressure difference is the driving force of mass transfer. The vapor pressure is generally assumed by the saturation pressure and calculated by the Antoine equation. However, in the actual operation process, the feed solutions usually flow in a [...] Read more.
In membrane distillation, the vapor pressure difference is the driving force of mass transfer. The vapor pressure is generally assumed by the saturation pressure and calculated by the Antoine equation. However, in the actual operation process, the feed solutions usually flow in a non-equilibrium state, which does not meet the theoretical and measurement conditions of the vapor-liquid equilibrium (VLE) state. This study tested the actual water vapor pressure of the pure water, lithium bromide (LiBr) solution, lithium chloride (LiCl) solution, and calcium chloride (CaCl2) solution under different flow conditions. The results showed that the actual water vapor pressure was lower than the saturation pressure overall, and the difference increased with temperature but decreased with the mass concentration. Therefore, in vacuum membrane distillation (VMD), air gap membrane distillation (AGMD), and sweeping gas membrane distillation (SGMD), the membrane flux calculated by water vapor saturation pressure was higher than the actual membrane flux, and the relative difference decreased and was less than 10% after 60 °C. In direct contact membrane distillation (DCMD), the water vapor pressure difference on both membrane sides was almost the same by using the saturation vapor pressure or the tested data since the pressure errors were partially offset in parallel flow or counter-flow modes. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

13 pages, 4062 KiB  
Article
Comparative Study on Water Vapour Resistance of Poly(lactic acid) Films Prepared by Blending, Filling and Surface Deposit
by Shuo Wang, Qinyu Shen, Chuanyan Guo and Hongge Guo
Membranes 2021, 11(12), 915; https://doi.org/10.3390/membranes11120915 - 23 Nov 2021
Cited by 4 | Viewed by 2323
Abstract
The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object, with a focus on PLA modification by using polymers such as linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and ethylene–propylene-diene monomer grafted with glycidyl methacrylate (EPDM-g-GMA), by using fillers such [...] Read more.
The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object, with a focus on PLA modification by using polymers such as linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and ethylene–propylene-diene monomer grafted with glycidyl methacrylate (EPDM-g-GMA), by using fillers such as nano calcium carbonate and zeolite. In order to characterize the deposition effect of Al2O3 on the film surface by plasma-assisted atomic layer deposition, Bio-oriented PLA (BOPLA) with more uniform thickness than blown film was purchased for study. The mechanical properties, friction coefficient, surface contact angle and water vapour transmission rate of the modified PLA film were compared and discussed. The aim was to find out the most influencing factors of film’s water vapour resistance. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

14 pages, 1418 KiB  
Article
An Assessment of Renewable Energies in a Seawater Desalination Plant with Reverse Osmosis Membranes
by Federico Leon and Alejandro Ramos
Membranes 2021, 11(11), 883; https://doi.org/10.3390/membranes11110883 - 17 Nov 2021
Cited by 4 | Viewed by 1908
Abstract
The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it [...] Read more.
The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it is possible to greatly reduce the carbon footprint of reverse osmosis plants. The objective of this study was to add a renewable energy supply to a desalination plant that uses reverse osmosis technology. During the development of this research study, photovoltaic energy was discarded as a possible source of renewable energy due to the wind conditions in the area in which the reverse osmosis plant was located; hence, the installation of a wind turbine was considered to be the best option. As it was a large-capacity reverse osmosis plant, we decided to divide the entire desalination process into several stages for explanation purposes. The desalination process of the facility consists of several phases: First, the seawater capture process was performed by the intake tower. This water was then transported and stored, before going through a physical and chemical pre-treatment process, whereby the highest possible percentage of impurities and organic material was eliminated in order to prevent the plugging of the reverse osmosis modules. After carrying out the appraisals and calculating the amount of energy that the plant consumed, we determined that 15% of the plant’s energy supply should be renewable, corresponding to 1194 MWh/year. As there was already a wind power installation in the area, we decided to use one of the wind turbines that had already been installed—specifically, an Ecotecnia turbine (20–150) that produced an energy of 1920 MWh /year. This meant that only a single wind turbine was required for this project. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

18 pages, 1375 KiB  
Article
Optimization of Energy Efficiency, Operation Costs, Carbon Footprint and Ecological Footprint with Reverse Osmosis Membranes in Seawater Desalination Plants
by Federico Leon, Alejandro Ramos and Sebastian O. Perez-Baez
Membranes 2021, 11(10), 781; https://doi.org/10.3390/membranes11100781 - 12 Oct 2021
Cited by 14 | Viewed by 2973
Abstract
This article shows the optimization of the reverse osmosis process in seawater desalination plants, taking the example of the Canary Islands, where there are more than 320 units of different sizes, both private and public. The objective is to improve the energy efficiency [...] Read more.
This article shows the optimization of the reverse osmosis process in seawater desalination plants, taking the example of the Canary Islands, where there are more than 320 units of different sizes, both private and public. The objective is to improve the energy efficiency of the system in order to save on operation costs as well as reduce the carbon and ecological footprints. Reverse osmosis membranes with higher surface area have lower energy consumption, as well as energy recovery systems to recover the brine pressure and introduce it in the system. Accounting for the operation, maintenance and handling of the membranes is also important in energy savings, in order to improve the energy efficiency. The energy consumption depends on the permeate water quality required and the model of the reverse osmosis membrane installed in the seawater desalination plant, as it is shown in this study. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

11 pages, 25862 KiB  
Article
Performance Analysis of a Full-Scale Desalination Plant with Reverse Osmosis Membranes for Irrigation
by Federico Leon and Alejandro Ramos
Membranes 2021, 11(10), 774; https://doi.org/10.3390/membranes11100774 - 11 Oct 2021
Cited by 3 | Viewed by 4505
Abstract
Reverse osmosis (RO) is the most widely used technology for seawater desalination purposes. The long-term operating data of full-scale plants is key to analyse their performance under real conditions. The studied seawater reverse osmosis (SWRO) desalination plant had a production capacity of 5000 [...] Read more.
Reverse osmosis (RO) is the most widely used technology for seawater desalination purposes. The long-term operating data of full-scale plants is key to analyse their performance under real conditions. The studied seawater reverse osmosis (SWRO) desalination plant had a production capacity of 5000 m3/d for irrigation purposes. The operating data such as conductivities flows, and pressures were collected for around 27,000 h for 4 years. The plant had sand and cartridge filters without chemical dosing in the pre-treatment stage, a RO system with one stage, 56 pressure vessels, seven RO membrane elements per pressure vessel and a Pelton turbine as energy recovery device. The operating data allowed to calculate the average water and salt permeability coefficients (A and B) of the membrane as well as the specific energy consumption (SEC) along the operating period. The calculation of the average A in long-term operation allowed to fit the parameters of three different models used to predict the mentioned parameter. The results showed a 30% decrease of A, parameter B increase around 70%. The SEC was between 3.75 and 4.25 kWh/m3. The three models fitted quite well to the experimental data with standard deviations between 0.0011 and 0.0015. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

50 pages, 6942 KiB  
Article
Design and Implementation of an Electrical Characterization System for Membrane Capacitive Deionization Units for the Water Treatment
by Federico A. Leon, Alejandro Ramos-Martin and David Santana
Membranes 2021, 11(10), 773; https://doi.org/10.3390/membranes11100773 - 11 Oct 2021
Cited by 1 | Viewed by 2625
Abstract
The desalination of seawater is one of the most established techniques in the world. In the middle of the 20th century this was achieved using water evaporation systems, later with reverse osmosis membranes and nowadays with the possibility of capacitive deionization membranes. Capacitive [...] Read more.
The desalination of seawater is one of the most established techniques in the world. In the middle of the 20th century this was achieved using water evaporation systems, later with reverse osmosis membranes and nowadays with the possibility of capacitive deionization membranes. Capacitive deionization and membrane capacitive deionization are an emerging technology that make it possible to obtain drinking water with an efficiency of 95%. This technology is in the development stage and consists of porous activated carbon electrodes, which have great potential for saving energy in the water desalination process and can be used for desalination using an innovative technology called capacitive deionization (CDI), or membrane capacitive deionization (MCDI) if an anion and cation membrane exchange is used. In this paper is proposed and designed a characterization system prototype for CDI and MCDI that can operate with constant current charging and discharging (galvanostatic method). Adequate precision has been achieved, as can be seen in the results obtained. These results were obtained from the performance of typical characterization tests with electrochemical double layer capacitors (EDLC), since they are electrochemical devices that behave similarly to MCDI, from the point of view of the electrical variables of the processes that take place in MCDI. A philosophy of using free software with open-source code has been followed, with software such as the Arduino and Processing programming editors (IDE), as well as the Arduino Nano board (ATmega328), the analogical-digital converter (ADC1115) and the digital-analogical converter (MCP4725). Moreover, a low-cost system has been developed. A robust and versatile system has been designed for water treatment, and a flexible system has been obtained for the specifications established, as it is shown in the results section. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

18 pages, 5410 KiB  
Article
Facile Fabrication of Multi-Hydrogen Bond Self-Assembly Poly(MAAc-co-MAAm) Hydrogel Modified PVDF Ultrafiltration Membrane to Enhance Anti-Fouling Property
by Weigui Fu, Guoxia Li, Gaowei Zhai, Yunji Xie, Meixiu Sun, Patrick Théato, Yiping Zhao and Li Chen
Membranes 2021, 11(10), 761; https://doi.org/10.3390/membranes11100761 - 30 Sep 2021
Cited by 3 | Viewed by 2365
Abstract
In this work, a facile preparation method was proposed to reduce natural organics fouling of hydrophobic membrane via UV grafting polymerization with methacrylic acid (MAAc) and methyl acrylamide (MAAm) as hydrophilic monomers, followed by multihydrogen bond self-assembly. The resulting poly(vinylidene fluoride)-membranes were characterized [...] Read more.
In this work, a facile preparation method was proposed to reduce natural organics fouling of hydrophobic membrane via UV grafting polymerization with methacrylic acid (MAAc) and methyl acrylamide (MAAm) as hydrophilic monomers, followed by multihydrogen bond self-assembly. The resulting poly(vinylidene fluoride)-membranes were characterized with respect to monomer ratio, chemical structure and morphology, surface potential, and water contact angle, as well as water flux and organic foulants ultrafiltration property. The results indicated that the optimal membrane modified with a poly(MAAc-co-MAAm) polymer gel layer derived from a 1:1 monomer ratio exhibited superior hydrophilicity and excellent gel layer stability, even after ultrasonic treatment or soaking in acid or alkaline aqueous solution. The initial water contact angle of modified membranes was only 36.6° ± 2.9, and dropped to 0° within 13 s. Moreover, flux recovery rates (FRR) of modified membranes tested by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA) solution, respectively, were all above 90% after one-cycle filtration (2 h), significantly higher than that of the pure membrane (70–76%). The total fouling rates (Rt) of the pure membrane for three foulants were as high as 47.8–56.2%, while the Rt values for modified membranes were less than 30.8%. Where Rt of BSA dynamic filtration was merely 10.7%. The membrane designed through grafting a thin-layer hydrophilic hydrogel possessed a robust antifouling property and stability, which offers new insights for applications in pure water treatment or protein purification. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

11 pages, 13778 KiB  
Article
Impact of the Recovery on Concentrating Acetic Acid with Low-Pressure Reverse-Osmosis Membranes
by Giorgio Pratofiorito, Harald Horn and Florencia Saravia
Membranes 2021, 11(10), 742; https://doi.org/10.3390/membranes11100742 - 28 Sep 2021
Cited by 5 | Viewed by 2371
Abstract
This work deals with the optimization of the concentration of volatile fatty acids (VFAs) using low-pressure reverse osmosis (LPRO) membranes. Membrane filtration of a synthetic solution simulating the product of biomass hydrolysis was performed. Experiments were run on two flat-sheet XLE membranes under [...] Read more.
This work deals with the optimization of the concentration of volatile fatty acids (VFAs) using low-pressure reverse osmosis (LPRO) membranes. Membrane filtration of a synthetic solution simulating the product of biomass hydrolysis was performed. Experiments were run on two flat-sheet XLE membranes under 22 and 25 bar in continuous operation mode. Separation efficiency was evaluated for different recoveries. A correlation between the osmotic pressure of the concentrate and the parameter Rc, representative of the separation efficiency, was found. Under the conditions of the present study and taking into consideration the rejection properties of the applied membrane, a recovery of 33% and 44% is recommendable to maximize the ratio between the concentration of acetate in the concentrate and permeate and thus increase the total reclaim of acetic acid. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

15 pages, 4837 KiB  
Article
A Novel Composite Material UiO-66@HNT/Pebax Mixed Matrix Membranes for Enhanced CO2/N2 Separation
by Fei Guo, Bingzhang Li, Rui Ding, Dongsheng Li, Xiaobin Jiang, Gaohong He and Wu Xiao
Membranes 2021, 11(9), 693; https://doi.org/10.3390/membranes11090693 - 07 Sep 2021
Cited by 16 | Viewed by 3122
Abstract
Mixing a polymer matrix and nanofiller to prepare a mixed matrix membrane (MMM) is an effective method for enhancing gas separation performance. In this work, a unique UiO-66-decorated halloysite nanotubes composite material (UiO-66@HNT) was successfully synthesized via a solvothermal method and dispersed into [...] Read more.
Mixing a polymer matrix and nanofiller to prepare a mixed matrix membrane (MMM) is an effective method for enhancing gas separation performance. In this work, a unique UiO-66-decorated halloysite nanotubes composite material (UiO-66@HNT) was successfully synthesized via a solvothermal method and dispersed into the Pebax-1657 matrix to prepare MMMs for CO2/N2 separation. A remarkable characteristic of this MMM was that the HNT lumen provided the highway for CO2 diffusion due to the unique affinity of UiO-66 for CO2. Simultaneously, the close connection of the UiO-66 layer on the external surface of HNTs created relatively continuous pathways for gas permeation. A suite of microscopy, diffraction, and thermal techniques was used to characterize the morphology and structure of UiO-66@HNT and the membranes. As expected, the embedding UiO-66@HNT composite materials significantly improved the separation performances of the membranes. Impressively, the as-obtained membrane acquired a high CO2 permeability of 119.08 Barrer and CO2/N2 selectivity of 76.26. Additionally, the presence of UiO-66@HNT conferred good long-term stability and excellent interfacial compatibility on the MMMs. The results demonstrated that the composite filler with fast transport pathways designed in this study was an effective strategy to enhance gas separation performance of MMMs, verifying its application potential in the gas purification industry. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

13 pages, 6420 KiB  
Article
Effects of Processing Conditions and Plasticizing-Reinforcing Modification on the Crystallization and Physical Properties of PLA Films
by Shuo Wang, Baodong Liu, Yingying Qin and Hongge Guo
Membranes 2021, 11(8), 640; https://doi.org/10.3390/membranes11080640 - 20 Aug 2021
Cited by 11 | Viewed by 3154
Abstract
The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object. Epoxy soybean oil (ESO) and zeolite (3A molecular sieve) were used as plasticizer and reinforcing filler, respectively, for PLA blend modification. The mixture was granulated in an extruder and then [...] Read more.
The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object. Epoxy soybean oil (ESO) and zeolite (3A molecular sieve) were used as plasticizer and reinforcing filler, respectively, for PLA blend modification. The mixture was granulated in an extruder and then blown to obtain films under different conditions to determine the optimum processing temperatures and screw rotation. Then, the thermal behaviour, crystallinity, optical transparency, micro phase structure and physical properties of the film were investigated. The results showed that with increasing zeolite content, the crystallization behaviour of PLA changed, and the haze of the film increased from 5% to 40% compared to the pure PLA film. Zeolite and ESO dispersed in the PLA matrix played a role in toughening and strengthening. The PLA/8 wt% zeolite/3 wt% ESO film had the highest longitudinal tensile strength at 77 MPa. The PLA/2 wt% zeolite/3 wt% ESO film had the highest longitudinal elongation at 13%. The physical properties depended heavily on the dispersion of zeolite and ESO in the matrix. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Graphical abstract

35 pages, 7848 KiB  
Article
Silica Fouling in Reverse Osmosis Systems–Operando Small-Angle Neutron Scattering Studies
by Vitaliy Pipich, Thomas Starc, Johan Buitenhuis, Roni Kasher, Winfried Petry, Yoram Oren and Dietmar Schwahn
Membranes 2021, 11(6), 413; https://doi.org/10.3390/membranes11060413 - 30 May 2021
Cited by 3 | Viewed by 2682
Abstract
We present operando small-angle neutron scattering (SANS) experiments on silica fouling at two reverse osmose (RO) membranes under almost realistic conditions of practiced RO desalination technique. To its realization, two cells were designed for pressure fields and tangential feed cross-flows up to 50 [...] Read more.
We present operando small-angle neutron scattering (SANS) experiments on silica fouling at two reverse osmose (RO) membranes under almost realistic conditions of practiced RO desalination technique. To its realization, two cells were designed for pressure fields and tangential feed cross-flows up to 50 bar and 36 L/h, one cell equipped with the membrane and the other one as an empty cell to measure the feed solution in parallel far from the membrane. We studied several aqueous silica dispersions combining the parameters of colloidal radius, volume fraction, and ionic strength. A relevant result is the observation of Bragg diffraction as part of the SANS scattering pattern, representing a crystalline cake layer of simple cubic lattice structure. Other relevant parameters are silica colloidal size and volume fraction far from and above the membrane, as well as the lattice parameter of the silica cake layer, its volume fraction, thickness, and porosity in comparison with the corresponding permeate flux. The experiments show that the formation of cake layer depends to a large extent on colloidal size, ionic strength and cross-flow. Cake layer formation proved to be a reversible process, which could be dissolved at larger cross-flow. Only in one case we observed an irreversible cake layer formation showing the characteristics of an unstable phase transition. We likewise observed enhanced silica concentration and/or cake formation above the membrane, giving indication of a first order liquid–solid phase transformation. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Graphical abstract

17 pages, 5446 KiB  
Article
Cu(I/II) Metal–Organic Frameworks Incorporated Nanofiltration Membranes for Organic Solvent Separation
by Lakshmeesha Upadhyaya, Yu-Hsuan Chiao, S. Ranil Wickramasinghe and Xianghong Qian
Membranes 2020, 10(11), 313; https://doi.org/10.3390/membranes10110313 - 29 Oct 2020
Cited by 11 | Viewed by 2909
Abstract
Copper-based metal–organic frameworks (MOFs) with different oxidation states and near-uniform particle sizes have been successfully synthesized. Mixed-matrix polyimide membranes incorporating 0.1–7 wt% of Cu(II) benzene-1,2,5-tricarboxylic acid (Cu(II)BTC), Cu(I/II)BTC and Cu(I) 1,2-ethanedisulfonic acid (EDS) (Cu(I)EDS) MOFs were fabricated via non-solvent-induced phase inversion process. These [...] Read more.
Copper-based metal–organic frameworks (MOFs) with different oxidation states and near-uniform particle sizes have been successfully synthesized. Mixed-matrix polyimide membranes incorporating 0.1–7 wt% of Cu(II) benzene-1,2,5-tricarboxylic acid (Cu(II)BTC), Cu(I/II)BTC and Cu(I) 1,2-ethanedisulfonic acid (EDS) (Cu(I)EDS) MOFs were fabricated via non-solvent-induced phase inversion process. These membranes are found to be solvent resistant and mechanically stable. Liquid phase nanofiltration experiments were performed to separate toluene from n-heptane at room temperature. These membranes demonstrate preferential adsorption and permeation of the aromatic toluene over aliphatic n-heptane. The amount of MOF particles incorporated, the oxidation state of the Cu ion and membrane, and barrier layer thickness have a significant impact on the separation factor. Toluene/heptane separation factor at 1.47, 1.67 and 1.79 can be obtained for membranes incorporating 7 wt% Cu(II)BTC, Cu(I/II)BTC and Cu(I)EDS respectively at room temperature. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Graphical abstract

9 pages, 597 KiB  
Article
Direct Measurements of Electroviscous Phenomena in Nafion Membranes
by David Nicolas Østedgaard-Munck, Jacopo Catalano and Anders Bentien
Membranes 2020, 10(11), 304; https://doi.org/10.3390/membranes10110304 - 25 Oct 2020
Viewed by 1754
Abstract
Investigation of electroviscous effects is of interest to technologies that exploit transport of ions through ion exchange membranes, charged capillaries, and porous media. When ions move through such media due to a hydrostatic pressure difference, they interact with the fixed charges, leading to [...] Read more.
Investigation of electroviscous effects is of interest to technologies that exploit transport of ions through ion exchange membranes, charged capillaries, and porous media. When ions move through such media due to a hydrostatic pressure difference, they interact with the fixed charges, leading to an increased hydraulic resistance. Experimentally this is observed as an apparent increase in the viscosity of the solution. Electroviscous effects are present in all electrochemical membrane-based processes ranging from nanofiltration to fuel-cells and redox flow batteries. Direct measurements of electroviscous effects varying the applied ionic current through Nafion membranes have, to the best of the authors’ knowledge, not yet been reported in literature. In the current study, electroviscous phenomena in different Nafion ion exchange membranes are measured directly with a method where the volume permeation is measured under constant trans-membrane pressure difference while varying the ion current density in the membrane. The direct measurement of the electroviscous effect is compared to the one calculated from the phenomenological transport equations and measured transport coefficients. Within the experimental uncertainty, there is a good agreement between the two values for all membranes tested. We report here an electroviscous effect for all Nafion membranes tested to be κH?κH−1=1.15−0.052+0.035. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Graphical abstract

Review

Jump to: Research

17 pages, 2673 KiB  
Review
Progress in the Degradability of Biodegradable Film Materials for Packaging
by Chuanyan Guo and Hongge Guo
Membranes 2022, 12(5), 500; https://doi.org/10.3390/membranes12050500 - 06 May 2022
Cited by 24 | Viewed by 4168
Abstract
In today’s world, the problem of “white pollution” is becoming more and more serious, and many countries have paid special attention to this problem, and it has become one of the most important tasks to reduce polymer waste and to protect the environment. [...] Read more.
In today’s world, the problem of “white pollution” is becoming more and more serious, and many countries have paid special attention to this problem, and it has become one of the most important tasks to reduce polymer waste and to protect the environment. Due to the degradability, safety, economy and practicality of biodegradable packaging film materials, biodegradable packaging film materials have become a major trend in the packaging industry to replace traditional packaging film materials, provided that the packaging performance requirements are met. This paper reviews the degradation mechanisms and performance characteristics of biodegradable packaging film materials, such as photodegradation, hydrodegradation, thermo-oxidative degradation and biodegradation, focuses on the research progress of the modification of biodegradable packaging film materials, and summarizes some challenges and bottlenecks of current biodegradable packaging film materials. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

13 pages, 2603 KiB  
Review
Research Progress of Polyvinyl Alcohol Water-Resistant Film Materials
by Baodong Liu, Jianhua Zhang and Hongge Guo
Membranes 2022, 12(3), 347; https://doi.org/10.3390/membranes12030347 - 20 Mar 2022
Cited by 45 | Viewed by 9416
Abstract
Polyvinyl alcohol (PVA) is one of the few biodegradable synthetic resins from petroleum-based sources that can alleviate white pollution in the environment. PVA film materials have excellent properties, such as high barrier, high transparency, high toughness, biocompatibility, and adjustable water solubility. However, due [...] Read more.
Polyvinyl alcohol (PVA) is one of the few biodegradable synthetic resins from petroleum-based sources that can alleviate white pollution in the environment. PVA film materials have excellent properties, such as high barrier, high transparency, high toughness, biocompatibility, and adjustable water solubility. However, due to the presence of hydrophilic hydroxyl groups in the side chain of PVA resin, when PVA film is placed in a humid or water environment, swelling or even dissolution will occur, which greatly limits its application. Therefore, it is necessary to modify PVA resin to improve water resistance without reducing other properties and can also impart various functionalities to it, thereby widening the application range. This paper reviews the water-resistant modification methods of polyvinyl alcohol and the application of water-resistant films and provides an outlook on the development trend of PVA water-resistant films. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

27 pages, 1658 KiB  
Review
Review of Transport Phenomena and Popular Modelling Approaches in Membrane Distillation
by Yan Dong, Xiaodong Dai, Lianyu Zhao, Li Gao, Zongli Xie and Jianhua Zhang
Membranes 2021, 11(2), 122; https://doi.org/10.3390/membranes11020122 - 08 Feb 2021
Cited by 35 | Viewed by 4261
Abstract
In this paper, the transport phenomena in four common membrane distillation (MD) configurations and three popular modelling approaches are introduced. The mechanism of heat transfer on the feed side of all configurations are the same but are distinctive from each other from the [...] Read more.
In this paper, the transport phenomena in four common membrane distillation (MD) configurations and three popular modelling approaches are introduced. The mechanism of heat transfer on the feed side of all configurations are the same but are distinctive from each other from the membrane interface to the bulk permeate in each configuration. Based on the features of MD configurations, the mechanisms of mass and heat transfers for four configurations are reviewed together from the bulk feed to the membrane interface on the permeate but reviewed separately from the interface to the bulk permeate. Since the temperature polarisation coefficient cannot be used to quantify the driving force polarisation in Sweeping Gas MD and Vacuum MD, the rate of driving force polarisation is proposed in this paper. The three popular modelling approaches introduced are modelling by conventional methods, computational fluid dynamics (CFD) and response surface methodology (RSM), which are based on classic transport mechanism, computer science and mathematical statistics, respectively. The default assumptions, area for applications, advantages and disadvantages of those modelling approaches are summarised. Assessment and comparison were also conducted based on the review. Since there are only a couple of full-scale plants operating worldwide, the modelling of operational cost of MD was only briefly reviewed. Gaps and future studies were also proposed based on the current research trends, such as the emergence of new membranes, which possess the characteristics of selectivity, anti-wetting, multilayer and incorporation of inorganic particles. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Graphical abstract

18 pages, 2272 KiB  
Review
A Review on Current Development of Membranes for Oil Removal from Wastewaters
by Brian Bolto, Jianhua Zhang, Xing Wu and Zongli Xie
Membranes 2020, 10(4), 65; https://doi.org/10.3390/membranes10040065 - 07 Apr 2020
Cited by 55 | Viewed by 5653
Abstract
The current situation with the problems associated with the removal of oil from wastewaters by membranes is being explored. Many types of membranes have been investigated—organic polymers, inorganic or ceramic species and hybrids of the two. Polymeric membranes can be designed to facilitate [...] Read more.
The current situation with the problems associated with the removal of oil from wastewaters by membranes is being explored. Many types of membranes have been investigated—organic polymers, inorganic or ceramic species and hybrids of the two. Polymeric membranes can be designed to facilitate the passage of oil, but the more successful approach is with hydrophilic types that encourage the passage of water. Ceramic membranes have an advantage here as they are less often irreversibly fouled and give a higher recovery of oil, with a lower flux decline. Furthermore, they can be cleaned up by a simple heating procedure. More attention should be given to understanding the mechanism of fouling so that operating conditions can be optimised to further reduce fouling and further decrease the flux decline, as well as assisting in the design of antifouling membranes. Another obstacle to ceramic membrane use is the high cost of manufacture. Cheaper starting materials such as clays have been surveyed. Full article
(This article belongs to the Special Issue Theoretical and Experimental Investigation of the Mass and Heat Transfers in Membrane Separation Processes)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-17
Back to TopTop