Journal of Membrane Science Letters最新文献

{"title":"The solution-diffusion model: “Rumors of my death have been exaggerated”","authors":"","doi":"10.1016/j.memlet.2024.100084","DOIUrl":"10.1016/j.memlet.2024.100084","url":null,"abstract":"<div><p>The solution-diffusion (SD) model has been instrumental in the advancement of membrane science, due to its simplicity, transparency, and utility in process engineering. However, some doubts have recently been raised, concerning the fundamental validity of SD. These have largely been based on apparent discrepancies between molecular dynamics simulations and several features, deemed inherent to SD, that appeared in early reports — namely, the exact nature of the pressure and concentration distributions within the membrane. Herein, we re-visit the underlying physics of SD in the context of composite membranes, making no a-priori assumptions and, particularly, highlighting the role of polymer thermodynamics and the mechanics of a loaded, swollen film, supported by a porous substrate. The analysis provides a coherent view, linking the solvent concentration profile within the film and the resultant flux-pressure relations with the polymer rigidity and, importantly, the way in which the film is supported. It is shown that, although the flux may generally vary non-linearly with the feed pressure and depend on the film-support geometry, for rigid films – most common in real operations – SD predicts a linear behavior, virtually independent of specific geometry and pressure distribution. Moving forward, we stress the importance and need for further refinements of the SD model, driven by insight from molecular dynamics, thermodynamics and mechanics, while maintaining its applicability to process design.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000187/pdfft?md5=3aef864909003eb19f6cf1bca2828a98&pid=1-s2.0-S2772421224000187-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incorporation of polyzwitterions in superabsorbent network membranes for enhanced saltwater absorption and retention","authors":"","doi":"10.1016/j.memlet.2024.100083","DOIUrl":"10.1016/j.memlet.2024.100083","url":null,"abstract":"<div><h3>Background</h3><p>Superabsorbent polymers (SAPs) have a remarkable ability to absorb significant quantities of water. However, their absorption capacity is significantly reduced when exposed to saline solutions, such as urine, due to the polyelectrolyte effect and charge screening.</p></div><div><h3>Methods</h3><p>In this study, we demonstrate a zwitterionic superabsorbent polymer (ZSAP) with excellent salt-water absorption and retention capacities. ZSAP was synthesized by grafting a copolymer of p(sulfobetaine methacrylate-<em>co</em>-2-hydroxyethyl methacrylate) (p(SBMA-<em>co</em>-HEMA)) onto an acrylic acid (AA)-based hydrogel via free-radical polymerization. The introduction of zwitterionic SBMA significantly enhances the hydrophilicity of the polymer, particularly in a saline solution due to the anti-polyelectrolyte effect, thereby accelerating the rate of salt absorption. Additionally, the hydroxyl groups from HEMA facilitate the formation of covalent bonds with the AA network membrane through esterification, effectively mitigating polymer leaching. The hydration/dehydration behaviors of linear polymers were measured using the dynamic vapor sorption (DVS) method. Moreover, the salt-water absorption capacity, centrifuge retention capacity (CRC), and absorbency under load (AUL) of ZSAP with various SBMA moieties and copolymer dosages were comprehensively evaluated in a 0.9 wt% sodium chloride solution. Additionally, the water retention under different temperatures and polymer leaching of ZSAP were investigated.</p></div><div><h3>Significant Findings</h3><p>The copolymer p(SBMA-<em>co</em>-HEMA) not only demonstrates a high salt-water absorption rate at 90% RH in a 0.9 wt% NaCl solution but also exhibits superior water retention at 0% RH compared to the AA polymer. Moreover, the ZSAP exhibits superior salt-water absorption capacity and AUL in a 0.9 wt% NaCl solution compared to conventional AA-based SAP. Additionally, the introduction of the hydroxyl moiety from the p(SBMA-<em>co</em>-HEMA) copolymer reduces free polymer leaching from ZSAP. This work presents an approach for the development of new SAP with high salt-water absorption and retention.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000175/pdfft?md5=8a876de88c228d5090fcc58cd47e9949&pid=1-s2.0-S2772421224000175-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142128482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polyvinylidene fluoride-alkali lignin blend: A new candidate for membranes development","authors":"","doi":"10.1016/j.memlet.2024.100081","DOIUrl":"10.1016/j.memlet.2024.100081","url":null,"abstract":"<div><p>New blend membranes consisting of a tuned ratio of polyvinylidene fluoride (PVDF) and alkali lignin (AL) were studied. Through the use of a green solvent like dimethyl sulfoxide, effective mixing between PVDF and AL was achieved, leading to the development of highly hydrophilic membranes with robust mechanical stability. Characterization methods confirmed the suitability of the blend for membrane preparation and its hydrophilic nature.</p><p>A key aspect of the strategy involved hydrophilizing PVDF during the preparation process by blending it with AL in the pot. This approach aimed to streamline production by reducing the number of steps compared to post-treatment methods such as grafting or coating. The presence of hydrophobic/hydrophilic groups in the AL structure addressed the challenge of compatibility between PVDF and conventional hydrophilic polymers, enhancing interaction between the components.</p><p>The resulting hydrophilic material exhibited improved pure water permeance and demonstrated resistance to irreversible fouling. The membrane's ability to process wastewater streams and its resistance to fouling was demonstrated by separating stable and uniform submicron oil-in-water emulsions with high rejection (&gt;99.9 %) up to a volume reduction factor (VRF) of 7.7.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000151/pdfft?md5=aa92dbc31fdee0cb574b9097a0a31edf&pid=1-s2.0-S2772421224000151-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conquering surfactant-induced partial wetting of commercial membrane in membrane distillation through in-situ water flushing","authors":"","doi":"10.1016/j.memlet.2024.100082","DOIUrl":"10.1016/j.memlet.2024.100082","url":null,"abstract":"<div><p>Surfactant-induced wetting impedes the practical implementation of membrane distillation (MD). Addressing this issue demands the development of an effective membrane cleaning strategy that can eliminate surfactants adhering to the membrane surface and restore the membrane hydrophobicity. However, current cleaning methods, such as direct drying and pressurized air backwashing, encounter challenges in thoroughly removing surfactants trapped within the pores while preserving the structural integrity of the membrane. This work presents a refined approach to conquer surfactant-induced wetting in MD by water flushing. Utilizing ultrasonic time domain reflectometry and optical coherence tomography techniques, we identified a critical cleaning depth and showed that the hydrophobicity of a partially wetted membrane can be fully recovered by water flushing when the wetting depth is below the critical threshold. Theoretical models evidenced that in instances of low water temperature and low flow rate conditions, relatively high critical cleaning depths can be realized, thereby expanding the operational scope for achieving complete hydrophobicity recovery. Our results demonstrated the applicability of water flushing to commercial membrane modules without necessitating any modification, emphasizing its substantial potential for advancing MD applications.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000163/pdfft?md5=f72a2ab796c7a5c91f6e295161719faa&pid=1-s2.0-S2772421224000163-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Desalination of complex saline waters: sulfonated pentablock copolymer pervaporation membranes do not fail when exposed to scalants and surfactants","authors":"","doi":"10.1016/j.memlet.2024.100080","DOIUrl":"10.1016/j.memlet.2024.100080","url":null,"abstract":"<div><p>As a vapor pressure-driven process, pervaporation (PV) shares several of the advantages of membrane distillation (MD), such as the ability to tackle high salinity waters and the possibility of integrating low grade heat sources to reduce energy consumption. Membrane scaling and pore wetting remain strong limitations to the implementation of MD desalination. In comparison, dense, non-porous PV membranes are considered. In this study, PV membranes made from NEXAR^TM, a sulfonated pentablock copolymer, were evaluated and compared to polytetrafluoroethylene (PTFE) MD membranes in a vacuum configuration. The membranes were tested using three solutions: 32 g L^-1 sodium chloride (NaCl), a brackish water (8.4 g L^-1) of high scaling potential, and 5.5 g L^-1 NaCl with 1 mM sodium dodecyl sulfate. The NEXAR^TM membrane achieved a permeance of 93.1±44.6 kg m^-2 h^-1 bar^-1 for the 32 g L^-1 brine, which was almost 20% higher than the PTFE MD membrane. This permeance decreased in the presence of foulants; however, in contrast with the MD membrane, where scaling and surfactants induced pore wetting, the salt rejection for the NEXAR^TM PV membrane was constant at &gt;99% for all water types. These results emphasize the robustness of PV as a process to deal with challenging saline waters.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277242122400014X/pdfft?md5=536fe3e31ef071d80e71b4c2f2148846&pid=1-s2.0-S277242122400014X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141979324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt partitioning and transport in polyamide reverse osmosis membranes at ultrahigh pressures","authors":"","doi":"10.1016/j.memlet.2024.100079","DOIUrl":"10.1016/j.memlet.2024.100079","url":null,"abstract":"<div><p>Understanding salt and water transport mechanisms in reverse osmosis (RO) under high pressures and salinities is critical to advancing RO-based brine management technologies. In this study, we investigate the dependence of salt permeance and partitioning on feed salinity and applied pressure. Salt partitioning coefficients were determined using a novel high-pressure quartz crystal microbalance (QCM), and salt permeances were collected using a lab-scale high-pressure dead-end cell. Our results show that salt permeance decreases with respect to feed concentration, in contrast to conventional theories for charged RO membranes. We further show salt partitioning coefficients do not change with applied hydrostatic pressure but are dependent on feed salt concentration. We use non-equilibrium molecular dynamics simulations to show that these trends are explained by salinity and pressure-induced changes to the structure of the polyamide layer, namely osmotic deswelling and compaction. Changes in the polyamide layer thickness and pore size alter the frictional interactions of ions, affecting membrane performance at larger salinities and pressures. These results provide new insights on how structure-performance relationships affect salt transport at higher pressures.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000138/pdfft?md5=826dd12271ae7855aa58311f2c09b7ac&pid=1-s2.0-S2772421224000138-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141622910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Charge-patterned nanofiltration membranes with polystyrene sulfonate particles and polyethyleneimine in cross-linked polyvinyl alcohol","authors":"","doi":"10.1016/j.memlet.2024.100078","DOIUrl":"10.1016/j.memlet.2024.100078","url":null,"abstract":"<div><p>Removing salinity has always been a challenge for wastewater treatment. Utilizing nanofiltration (NF) membranes is a promising approach. However, currently available NF membranes are less effective in monovalent salt removal. In this study, work toward the initial aim of fabricating charge mosaic membranes led to charge-patterned NF-selective films on polyether sulfone (PES) or polyacrylonitrile (PAN) support membranes, with similar rejection for mono- and divalent salts. The membranes were fabricated by a two-step layer assembly of first negatively charged polystyrene sulfonate (PSS) particles immobilized in a polyvinyl alcohol (PVA) layer, followed by coating a positively charged polyethyleneimine (PEI) layer. Both PVA and PEI were crosslinked using glutaraldehyde that had initially been impregnated into the support membrane. The type of support membrane, nanoparticle, PVA, and PEI concentrations during fabrication, as well as feed pH and salt concentration, play significant roles in separation performance of obtained composite membranes. Charge-patterned NF membranes fabricated using 0.5 wt.% PVA and 0.05 wt.% PSS for assembly of the first layer followed by coating 0.5 wt.% PEI solution had even somewhat higher rejection for monovalent salt (NaCl; ∼82%) compared to multivalent salts (Na₂SO₄, MgSO₄, and MgCl₂; ∼74%), at a permeance of 5.5 LMH/bar on the PES and 3.1 LMH/bar on the PAN support membrane.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000126/pdfft?md5=fe4f38456e65fab7493e29dffa1f4c18&pid=1-s2.0-S2772421224000126-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141629790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of surfactant properties on pore wetting of membrane distillation","authors":"Connor Coolidge ,&nbsp;Azal Mohammed Hassan Alhadidi ,&nbsp;Wei Wang ,&nbsp;Tiezheng Tong","doi":"10.1016/j.memlet.2024.100077","DOIUrl":"https://doi.org/10.1016/j.memlet.2024.100077","url":null,"abstract":"<div><p>Pore wetting is a major constraint to the performance of membrane distillation (MD) for hypersaline brine treatment. Despite the existence of surfactants with diverse properties, an explicit relationship between the properties of surfactants and their capabilities of inducing pore wetting has yet to be established. In this study, we perform a comparative analysis of the wetting behaviors of various surfactants with different charges and molecular weights in MD desalination. The induction time of surfactants to initiate pore wetting was correlated to the apparent contact angle and surface tension of the feedwater. Our results show that different surfactants resulting in similar feedwater surface tensions can lead to drastically different wetting potential, suggesting that both charge of the head group and molecular weight of surfactants have a significant influence on membrane pore wetting. Further, we demonstrate that parameters that have been commonly used to indicate wetting potential, including apparent contact angle and solution surface tension, are not reliable in predicting the wetting behavior of MD membranes, which is intricately linked with surfactant properties such as charge and molecular size. We envision that our results not only improve our fundamental understanding of surfactant-induced wetting but also provide valuable insights that necessitate thorough consideration of surfactant properties in evaluating wetting potential and membrane wetting resistance for MD desalination.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000114/pdfft?md5=3e6d124a373ac90da221d14e03d54437&pid=1-s2.0-S2772421224000114-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141291758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigating phase changes in the gas-phase that disrupt CO2 capture in membrane contactors: CO2-NH3-H2O as a model ternary system","authors":"B.A. Luqmani ,&nbsp;V. Nayak ,&nbsp;A. Brookes ,&nbsp;A. Moore ,&nbsp;P. Vale ,&nbsp;M. Pidou ,&nbsp;E.J. McAdam","doi":"10.1016/j.memlet.2024.100076","DOIUrl":"https://doi.org/10.1016/j.memlet.2024.100076","url":null,"abstract":"<div><p>Solid and liquid products can form in the gas phase of membrane contactors applied to reactive ternary systems for CO₂ absorption, which poses a critical barrier for carbon capture applications. The mechanism initiating these unwanted phase changes in the gas phase is unclear. This study therefore systematically characterises CO₂ absorption in distinct regions of the vapour-liquid equilibrium (VLE) within an illustrative ternary system (CO₂-NH₃-H₂O), to provide an explanation for the formation and mitigation of these solid and liquid products in the gas-phase. Unstable CO₂ absorption and increased pressure drop indicated product formation within the gas-phase, which occurred at high CO₂ capture ratios. Temporal analysis of gas-phase composition enabled gas-phase products to be related to the relative ternary composition. This was subsequently correlated to distinct regions of the VLE. Consequently, mitigation strategies can be developed with recognition for where products are least likely to form. Pressurisation was proposed to modify the relative gas-phase ammonia composition to reposition conditions within the VLE. The commensurate increase of CO₂ into the solvent shifts the ammonia-ammonium equilibrium towards ammonium to indirectly reduce vapour pressure. This synergistic strategy allows sustained operation of membrane contactors for CO₂ separation within reactive ternary systems which are critical to delivering carbon capture economically at scale.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000102/pdfft?md5=a3fd87a26bef61679123f37cbda615e2&pid=1-s2.0-S2772421224000102-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141240021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-cost automated flat-sheet membrane casting: An open-source, advanced manufacturing approach","authors":"Nathan Mullins,&nbsp;Irina Babamova,&nbsp;Charles-François de Lannoy,&nbsp;David R. Latulippe","doi":"10.1016/j.memlet.2024.100075","DOIUrl":"10.1016/j.memlet.2024.100075","url":null,"abstract":"<div><p>Novel membrane materials developed in research labs struggle to gain widespread industrial adoption due in part to insufficient reproducibility and unreliable performance data. Open-source hardware approaches, especially 3D printing, enable the democratization of automation within a laboratory setting, and in the context of membranes, can minimize the inherent variability associated with manual methods of membrane casting. In this study, the native hardware and firmware of an inexpensive, conventional 3D printer was extensively modified for the purpose of flat-sheet membrane casting. Replicate poly (ether-ether ketone) (PEEK) membranes were cast with a thickness coefficient of variation of ∼10 % using the modified device. Cast membranes were used to assess the importance of controlling shear rate by characterizing both intra- and inter-film variability. Statistical differences in pure water permeability were observed across tested shear rates, with distinct morphological changes occurring to the membrane substructure. Overall, the technology developed in this study is shown to be an extremely useful approach for improving the process of developing membranes at the bench-scale.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421224000096/pdfft?md5=0d3606fe070e4aee871a825dd4437df6&pid=1-s2.0-S2772421224000096-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141052940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}