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Volume 49 (2024)
- Issue 2 Pages 64-
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Volume 49, Issue 1
Displaying 1-10 of 10 articles from this issue
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Special Topic : Prospects of membrane technology for water treatment XIV-NF contributing to environmental-friendly industries-
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Daisuke Saeki2024 Volume 49 Issue 1 Pages 2-6
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSNanofiltration (NF) membranes have been applied to various applications such as pre–treatment of reverse osmosis (RO) membrane processes, separation and concentration of small organic molecules and multivalent ions. Polyamide membranes fabricated by interfacial polymerization are mainly used for NF membranes, because of their high water permeability and controllable separation performance. The improvement of the water permeability of NF membranes is crucial because it directly leads to energy efficiency. In this review, the recent approaches to improve the water permeability of polyamide NF membranes, including our new approach, “post–pore expansion”, are introduced. The “post–pore expansion” using methoxycarbonyl–diamine achieved the high water permeability comparable to nanomaterials-composite NF membranes.View full abstractDownload PDF (839K) -
Hiroki Nagasawa, Shun Aoyama, Taisei Makihara, Norihiro Moriyama, Masa ...2024 Volume 49 Issue 1 Pages 7-12
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSThis review discusses the application of bridged–organosilica membranes in ultra–high–pressure reverse osmosis (RO) for concentrating organic aqueous solutions, notably dimethylformamide (DMF) in wastewater. RO process offers a more energy–efficient alternative to traditional distillation, but it faces challenges such as high osmotic pressure and the need for durable membranes. The first half of this review summarizes the development of porous ceramic RO membranes with high selectivity and chemical stability, suitable for operating at high–pressure and high solvent concentration. These membranes, with their unique silica networks with organic bridging groups, demonstrate high rejection performance not only in aqueous system but also in solvent–solvent separation. The second half of this review introduces the multi–stage ultra–high pressure filtration process for concentrating organic aqueous solutions. A key innovation in the multi–stage process is to develop and combine high–rejection RO and lower–rejection nanofiltration (NF) membranes. The combination use of RO and NF enables efficient concentration at lower pressures. The simulation study indicates that a well–optimized process significantly reduces energy consumption and represents an effective solution for sustainable resource use.View full abstractDownload PDF (995K) -
Tsunenobu Katsura2024 Volume 49 Issue 1 Pages 13-18
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSContamination of portable water source with organic micropollutants (OMP) has increasingly been recognized as potential risk for the human health. Such contaminants include pesticide, herbicide, medicines, PFAS (per – and polyfluoroalkyl substance) and so on. These organic micropollutants as well as natural organic matter (NOM), humic acid in particular, which can act as trihalomethane precursor, could be removed by conventional spiral wound nanofiltration (NF) technology, however, it often requires extensive pretreatment, thus had to increase greenhouse gas emission in the entire treatment process while solving human health issue. In order to address this contradiction, hollow fiber direct nanofiltration (dNF) technology has been developed. The technology has been used for various applications all over the world, which include color and OMP removal from the surface waters. These case studies are discussed in this paper together with key features of the dNF membrane technology.View full abstractDownload PDF (1121K) -
Shigeru Aoyama, Tomoya Yoshizaki, Ryoma Miyamoto2024 Volume 49 Issue 1 Pages 19-23
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSNano–filtration (NF) membranes can selectively separate dissolved multivalent ions and monovalent ions generally. However, one downside of conventional ones is their vulnerability to highly acidic/alkaline solutions, limiting their application to solution in the neutral region. Another is insufficient selectivity for multivalent ions, hampering separation efficiency. Under these circumstances, we successfully created a highly durable & selective NF membrane. Additionally, we have developed a new membrane process utilizing this new membrane for resource recovery applications. Regarding the application to resource recovery of lithium from used lithium–ion batteries (LIBs), we are succeeded in recovering of lithium ion from mixed acidic solution with multivalent ions. If this is applied to LIB recycling system, it is expected to reduce CO2 emissions by 30% or more compared to conventional wet refining process.View full abstractDownload PDF (992K)
Special Topic : Current Status and Future Prospects of CO2 Capture by Front-Runners
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Hiroshi Machida2024 Volume 49 Issue 1 Pages 24-27
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSWe propose an energy–efficient carbon dioxide (CO2) capture system for Carbon Capture and Utilization (CCU). In our approach, CO2 reacts with hydrogen (H2) derived from renewable energy sources to produce methane. The gas mixture used in the reactor consists of CO2 and renewable–origin H2. When hydrogen is introduced into the CO2 desorption section of the separation process, the partial pressure of CO2 decreases, leading to an accelerated CO2 desorption. This acceleration significantly contributes to energy savings across various technologies, including absorption liquid, adsorbent, or membrane separation methods.View full abstractDownload PDF (705K) -
Eiji Kamio2024 Volume 49 Issue 1 Pages 28-33
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSA facilitated transport membrane (FTM) is a functional membrane with high permeability and excellent permselectivity. An FTM containing a chemical compound with a CO2–reactive amino group is a promising CO2 separation membrane. Especially, the FTMs have a unique property that the CO2 permeance increases with the decrease in the CO2 partial pressure. Therefore, FTMs are an effective CO2 separation membrane for direct CO2 capture from the air with extremely low CO2 concentration (Direct Air Capture: DAC). Among the FTMs for CO2 separation, those containing an amino–functionalized ionic liquid as the CO2 carrier can permeate CO2 faster than conventional FTMs even under low humidity conditions. In this paper, we investigate the applicability of a membrane module equipped with an amino acid ionic liquid–based FTM to a DAC process by conducting a process simulation. In the process simulation, we took into account the variation of the CO2 permeability of the FTM along with the changes in the composition of the feed gas in the CO2 separation membrane module.View full abstractDownload PDF (1246K) -
Satoshi Kodama2024 Volume 49 Issue 1 Pages 34-40
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSMembrane separation is a promising method for CO2 separation from flue gases with low cost and energy consumption. This process comprises membrane modules, blowers, compressors, and heat exchangers. Cost estimation of the equipment is required to compare the performance of the process with other separation processes, such as the chemical absorption process or adsorption process. This paper explains process design and cost estimation methods for CO2 separation by considering fixed and direct costs.View full abstractDownload PDF (1049K)
Special Topic : Membrane Award for Young Scientists (2023)
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Motomu Sakai, Masahiko Matsukata2024 Volume 49 Issue 1 Pages 41-45
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSThe effect of membrane structure on permeation and separation properties for hydrocarbons through silicalite–1 membranes were investigated. Two kinds of silicalite–1 membranes were synthesized by different preparation procedures. These effective pore sizes, micropore volumes, and permeation properties were evaluated using nano– permporometry, adsorption test, and vapor permeation test. These results showed that narrowness and obstruction of micropores could occur at the grain boundaries of silicalite–1 crystals. It was suggested that reducing grain boundaries and improve pore–connectivity by the controlling crystal–stacking structure was important to obtain a highly permeable membrane.View full abstractDownload PDF (917K)
Special Topic : Review Article : Engineering Subjects of Gas Separation Membranes Part 1: Design of Membrane Modules
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Kenji Haraya2024 Volume 49 Issue 1 Pages 46-56
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSThe basic mathematical equations required to analyze the performance of gas separation membranes are introduced, and the design methods for membrane modules are explained for four flow models: perfect mixing, co–current flow, cross flow, and counter–current flow. As specific calculations, the results of three cases of biomethane enrichment, N2 and O2 enrichment by air separation, and H2 and CO2 separation from reformed gas are presented, and the subjects and prospects are discussed. In addition, the paper introduces a high–efficiency process that improves separation performance and provides examples of calculations for efficiency comparisons.View full abstractDownload PDF (1150K)
Products Spotlight
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Yoshihide Kaiya2024 Volume 49 Issue 1 Pages 57-61
Published: 2024
Released on J-STAGE: January 29, 2024
JOURNAL RESTRICTED ACCESSWhen designing membrane filtration equipment, it is important to select membrane filtration flux and chemical cleaning frequency. This paper introduced the design support tool L–Valley®Rev.1 for membrane filtration process and explained its elemental technologies, the fouling potential (FP) and binary apparent cake blocking model (BACB model). Organic FP and coagulation FP are indicators that directly quantify membrane fouling matters such as biopolymers and aluminum nanoparticles as membrane filtration resistance. The four constants of the BACB model are derived from FP, and this model can be used to predict the increase in trans–membrane pressure in a coagulation–membrane filtration system.View full abstractDownload PDF (735K)
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