Pub Date : 2022-11-01DOI: 10.1016/j.memlet.2022.100026
Jingyi Wang , Zhongwei Cao , Xuefeng Zhu , Weishen Yang
High entropy perovskites bring more space for materials design in many fields. The stability of materials in thermodynamics can be improved by increasing the mixed entropy. In this work, a series of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) based high entropy perovskite (HEBSCF) were designed to improve the stability of BSCF at intermediate temperatures. The influence of high entropy composition on the lattice parameter, microstructure and stability of HEBSCF were investigated. The results show that HEBSCF can accommodate cations with large size differences. Compared with BSCF, doping elements at A site (HEBSCF-A), B site (HEBSCF-B) or both sites (HEBSCF-AB) can improve the mixed entropy. Among the three doped BSCF, HEBSCF-AB has the highest mixed entropy and shows stable oxygen permeation flux at 750 and 800 °C up to 300 h. No phase transition was observed on HEBSCF-AB after the long-term tests at intermediate temperatures. This research indicates that the high entropy stabilization strategy is feasible to improve the permeation stability of perovskite membranes by inhibiting phase transition.
{"title":"Improving intermediate-temperature stability of BSCF by constructing high entropy perovskites","authors":"Jingyi Wang , Zhongwei Cao , Xuefeng Zhu , Weishen Yang","doi":"10.1016/j.memlet.2022.100026","DOIUrl":"https://doi.org/10.1016/j.memlet.2022.100026","url":null,"abstract":"<div><p>High entropy perovskites bring more space for materials design in many fields. The stability of materials in thermodynamics can be improved by increasing the mixed entropy. In this work, a series of Ba<sub>0.5</sub>Sr<sub>0.5</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3-δ</sub> (BSCF) based high entropy perovskite (HEBSCF) were designed to improve the stability of BSCF at intermediate temperatures. The influence of high entropy composition on the lattice parameter, microstructure and stability of HEBSCF were investigated. The results show that HEBSCF can accommodate cations with large size differences. Compared with BSCF, doping elements at A site (HEBSCF-A), B site (HEBSCF-B) or both sites (HEBSCF-AB) can improve the mixed entropy. Among the three doped BSCF, HEBSCF-AB has the highest mixed entropy and shows stable oxygen permeation flux at 750 and 800 °C up to 300 h. No phase transition was observed on HEBSCF-AB after the long-term tests at intermediate temperatures. This research indicates that the high entropy stabilization strategy is feasible to improve the permeation stability of perovskite membranes by inhibiting phase transition.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 2","pages":"Article 100026"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000149/pdfft?md5=7acb9960cbea68003cedb1525ac7bca3&pid=1-s2.0-S2772421222000149-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137007658","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}
Pub Date : 2022-11-01DOI: 10.1016/j.memlet.2022.100025
Antoine Venault, Hana Nur Aini, Tesfaye Abebe Galeta, Yung Chang
The toxicity of common solvents used in membrane fabrication threatens the environmental sustainability and questions the claim that membrane technology is a green separation technology. Therefore, there is a need for re-orienting membrane fabrication processes towards greener solutions, making use of less toxic, and possibly environmentally friendly solvents. We employed dimethyl sulfoxide (DMSO), a non-toxic solvent, to prepare casting solutions containing polyvinylidene fluoride and an antifouling random copolymer made of polystyrene and poly(ethylene glycol) methyl ether methacrylate (PS-r-PEGMA). Membranes were formed by vapor-induced phase separation (VIPS). They were shown to be homogeneous in terms of structure and surface chemistry (tested by mapping FT-IR), suggesting compatibility of the polymer/copolymer/solvent system and justifying the choice of DMSO. Membrane hydration was drastically improved after adding PS-r-PEGMA with a water contact angle falling from 140° to 47°. As a result, biofouling by Escherichia coli and whole blood was reduced by > 90% in static conditions. During several filtration cycles of a highly fouling Escherichia coli solution flux recovery ratio could be increased from 16% (pristine membrane) to 29% (PEGylated membrane). All in all, this study reveals that low-biofouling homogeneous porous membranes can be prepared by in-situ modification and the VIPS process using a greener approach than traditionally reported.
{"title":"Using the dimethyl sulfoxide green solvent for the making of antifouling PEGylated membranes by the vapor-induced phase separation process","authors":"Antoine Venault, Hana Nur Aini, Tesfaye Abebe Galeta, Yung Chang","doi":"10.1016/j.memlet.2022.100025","DOIUrl":"10.1016/j.memlet.2022.100025","url":null,"abstract":"<div><p>The toxicity of common solvents used in membrane fabrication threatens the environmental sustainability and questions the claim that membrane technology is a green separation technology. Therefore, there is a need for re-orienting membrane fabrication processes towards greener solutions, making use of less toxic, and possibly environmentally friendly solvents. We employed dimethyl sulfoxide (DMSO), a non-toxic solvent, to prepare casting solutions containing polyvinylidene fluoride and an antifouling random copolymer made of polystyrene and poly(ethylene glycol) methyl ether methacrylate (PS-<em>r</em>-PEGMA). Membranes were formed by vapor-induced phase separation (VIPS). They were shown to be homogeneous in terms of structure and surface chemistry (tested by mapping FT-IR), suggesting compatibility of the polymer/copolymer/solvent system and justifying the choice of DMSO. Membrane hydration was drastically improved after adding PS-<em>r</em>-PEGMA with a water contact angle falling from 140° to 47°. As a result, biofouling by <em>Escherichia coli</em> and whole blood was reduced by > 90% in static conditions. During several filtration cycles of a highly fouling <em>Escherichia coli</em> solution flux recovery ratio could be increased from 16% (pristine membrane) to 29% (PEGylated membrane). All in all, this study reveals that low-biofouling homogeneous porous membranes can be prepared by <em>in-situ</em> modification and the VIPS process using a greener approach than traditionally reported.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 2","pages":"Article 100025"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000137/pdfft?md5=bad8639713799bd1e338b06d56f91381&pid=1-s2.0-S2772421222000137-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73332720","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}
Pub Date : 2022-11-01DOI: 10.1016/j.memlet.2022.100031
Yiming Zhang , Junyong Zhu , Jingwei Hou , Shouliang Yi , Bart Van der Bruggen , Yatao Zhang
Carbonic anhydrase (CA) based membranes with unique biological activities have been widely explored for carbon capture and storage (CCS), owing to their high efficiency, easy operation, low energy requirement, and environmental sustainability. However, limitations of CA enzymes, such as low thermal stabilities, narrow optimum pH ranges, and difficulties in recovery from reaction media, hinder its practical applications. Consequently, combining its enzymatic activity with membrane technologies for industrial uses is an attractive strategy. This current review explores a variety of immobilization approaches and summarizes the mechanistic features of enzymatic membranes in CO2 capture. Immobilized enzymes can be recycled to reduce process costs and improve the CO2 permeability and selectivity of the membranes. This makes enzymatic membranes attractive for CCS. The study also summarizes the structure, synthesis, and applications of a variety of CA analogues to demonstrate their advantages compared with natural CA. CA analogues hold promise for industrial and biomimetic applications.
{"title":"Carbonic anhydrase membranes for carbon capture and storage","authors":"Yiming Zhang , Junyong Zhu , Jingwei Hou , Shouliang Yi , Bart Van der Bruggen , Yatao Zhang","doi":"10.1016/j.memlet.2022.100031","DOIUrl":"10.1016/j.memlet.2022.100031","url":null,"abstract":"<div><p>Carbonic anhydrase (CA) based membranes with unique biological activities have been widely explored for carbon capture and storage (CCS), owing to their high efficiency, easy operation, low energy requirement, and environmental sustainability. However, limitations of CA enzymes, such as low thermal stabilities, narrow optimum pH ranges, and difficulties in recovery from reaction media, hinder its practical applications. Consequently, combining its enzymatic activity with membrane technologies for industrial uses is an attractive strategy. This current review explores a variety of immobilization approaches and summarizes the mechanistic features of enzymatic membranes in CO<sub>2</sub> capture. Immobilized enzymes can be recycled to reduce process costs and improve the CO<sub>2</sub> permeability and selectivity of the membranes. This makes enzymatic membranes attractive for CCS. The study also summarizes the structure, synthesis, and applications of a variety of CA analogues to demonstrate their advantages compared with natural CA. CA analogues hold promise for industrial and biomimetic applications.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 2","pages":"Article 100031"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000186/pdfft?md5=6fc827623716fb068c9ecfb1374dc5ef&pid=1-s2.0-S2772421222000186-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88726509","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}
Pub Date : 2022-11-01DOI: 10.1016/j.memlet.2022.100036
Chenyue Wu, Li Long, Zhe Yang, Chuyang Y. Tang
Fouling is a critical consideration for the design of thin-film composite (TFC) nanofiltration membranes. Traditional wisdom believes that fouling propensity is primarily dictated by membrane surface properties while porous substrates play little role (on the basis on the latter have no effect on the foulant-membrane interaction). Nevertheless, porous substrates can regulate the water transport pathways, resulting in uneven water flux distribution over the membrane surface. For the first time, we experimentally investigated the micro-scale water flux distribution for nanofiltration membranes with different substrate porosities and the impact of such flux distribution pattern on fouling. With gold nanoparticles as tracers, we demonstrated more evenly distributed water flux at increasing substrate porosity. This was found to effectively alleviate membrane fouling by eliminating localized hot spots of high flux. Furthermore, higher substrate porosity also effectively enhanced the membrane water permeance due to the optimized water transport pathways. Our study reveals the fundamental relationship between the micro-scale transport behavior and the membrane fouling propensity, which provides a firm basis for the rational design of TFC membranes toward better separation performance.
{"title":"Porous substrate affects fouling propensity of thin-film composite nanofiltration membranes","authors":"Chenyue Wu, Li Long, Zhe Yang, Chuyang Y. Tang","doi":"10.1016/j.memlet.2022.100036","DOIUrl":"10.1016/j.memlet.2022.100036","url":null,"abstract":"<div><p>Fouling is a critical consideration for the design of thin-film composite (TFC) nanofiltration membranes. Traditional wisdom believes that fouling propensity is primarily dictated by membrane surface properties while porous substrates play little role (on the basis on the latter have no effect on the foulant-membrane interaction). Nevertheless, porous substrates can regulate the water transport pathways, resulting in uneven water flux distribution over the membrane surface. For the first time, we experimentally investigated the micro-scale water flux distribution for nanofiltration membranes with different substrate porosities and the impact of such flux distribution pattern on fouling. With gold nanoparticles as tracers, we demonstrated more evenly distributed water flux at increasing substrate porosity. This was found to effectively alleviate membrane fouling by eliminating localized hot spots of high flux. Furthermore, higher substrate porosity also effectively enhanced the membrane water permeance due to the optimized water transport pathways. Our study reveals the fundamental relationship between the micro-scale transport behavior and the membrane fouling propensity, which provides a firm basis for the rational design of TFC membranes toward better separation performance.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 2","pages":"Article 100036"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277242122200023X/pdfft?md5=a57c70b8568a4633a9d5756b1a50855d&pid=1-s2.0-S277242122200023X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85498773","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2022.100014
Yang Han , W.S. Winston Ho
The CO2/N2 separation performances of facilitated transport membranes (FTMs) containing aminoacid salts as mobile carriers were characterized under dilute feed gases with 0.05–20% CO2. At a reduced CO2 partial pressure, the carrier saturation in the FTMs was mitigated, which enhanced both the CO2 permeance and CO2/N2 selectivity. The best FTM containing 2-(1-piperazinyl)ethylamine sarcosinate exhibited an uprising CO2 permeance from 1968 to 3822 GPU and an improved CO2/N2 selectivity from 249 to 472 with reducing CO2 content from 1% to 0.1%. The feasibility of this FTM is exemplified by designing a two-stage enriching membrane cascade to further remove 90% of the CO2 in a residual coal flue gas containing 1.75% CO2. Techno-economic analysis indicates a low capture cost of $83.8/tonne. The marginal costs beyond 90% capture are also evaluated for a variety of residual flue gases, indicating that the FTM-based capture from the coal or cement plant residual flue gas is more cost effective than direct air capture.
{"title":"Mitigated carrier saturation of facilitated transport membranes for decarbonizing dilute CO2 sources: An experimental and techno-economic study","authors":"Yang Han , W.S. Winston Ho","doi":"10.1016/j.memlet.2022.100014","DOIUrl":"10.1016/j.memlet.2022.100014","url":null,"abstract":"<div><p>The CO<sub>2</sub>/N<sub>2</sub> separation performances of facilitated transport membranes (FTMs) containing aminoacid salts as mobile carriers were characterized under dilute feed gases with 0.05–20% CO<sub>2</sub>. At a reduced CO<sub>2</sub> partial pressure, the carrier saturation in the FTMs was mitigated, which enhanced both the CO<sub>2</sub> permeance and CO<sub>2</sub>/N<sub>2</sub> selectivity. The best FTM containing 2-(1-piperazinyl)ethylamine sarcosinate exhibited an uprising CO<sub>2</sub> permeance from 1968 to 3822 GPU and an improved CO<sub>2</sub>/N<sub>2</sub> selectivity from 249 to 472 with reducing CO<sub>2</sub> content from 1% to 0.1%. The feasibility of this FTM is exemplified by designing a two-stage enriching membrane cascade to further remove 90% of the CO<sub>2</sub> in a residual coal flue gas containing 1.75% CO<sub>2</sub>. Techno-economic analysis indicates a low capture cost of $83.8/tonne. The marginal costs beyond 90% capture are also evaluated for a variety of residual flue gases, indicating that the FTM-based capture from the coal or cement plant residual flue gas is more cost effective than direct air capture.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100014"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000022/pdfft?md5=bc23429ddfd6e399497e81a45c762e84&pid=1-s2.0-S2772421222000022-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79170267","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2022.100024
Ekanem E. Ekanem , Ainur Sabirova , Ciarán Callaghan , Janet L. Scott , Karen J. Edler , Suzana P. Nunes , Davide Mattia
The production of sub-10 µm cellulose microbeads via membrane emulsification using isoporous membranes is reported here for the first time. Poly(ethylene terephthalate) membranes, with defined interpore distances, pore diameters and straight-through pores were fabricated via photolithography. A dispersed phase of 8 wt% cellulose solution was extruded through the membrane pores, forming, due to shear provided by an overhead stirrer, cellulose solution droplets dispersed in a continuous phase composed of 2 wt% and 5 wt% Span in sunflower oil. Upon phase inversion with ethanol, sub-10 µm microbeads with a coefficient of variation (CV) < 45 % were produced by exploring the Weber number (Wed) - Capillary number (Cac) emulsion generation space.
These results show that sub-10 µm cellulose microbeads can be produced using isoporous polymer membranes fabricated via photolithography, for use in a wide range of applications in the personal care, food and drug industries.
{"title":"Production of sub-10 micrometre cellulose microbeads using isoporous membranes","authors":"Ekanem E. Ekanem , Ainur Sabirova , Ciarán Callaghan , Janet L. Scott , Karen J. Edler , Suzana P. Nunes , Davide Mattia","doi":"10.1016/j.memlet.2022.100024","DOIUrl":"https://doi.org/10.1016/j.memlet.2022.100024","url":null,"abstract":"<div><p>The production of sub-10 µm cellulose microbeads via membrane emulsification using isoporous membranes is reported here for the first time. Poly(ethylene terephthalate) membranes, with defined interpore distances, pore diameters and straight-through pores were fabricated via photolithography. A dispersed phase of 8 wt% cellulose solution was extruded through the membrane pores, forming, due to shear provided by an overhead stirrer, cellulose solution droplets dispersed in a continuous phase composed of 2 wt% and 5 wt% Span in sunflower oil. Upon phase inversion with ethanol, sub-10 µm microbeads with a coefficient of variation (CV) < 45 % were produced by exploring the Weber number (<em>We<sub>d</sub></em>) - Capillary number (<em>Ca<sub>c</sub></em>) emulsion generation space.</p><p>These results show that sub-10 µm cellulose microbeads can be produced using isoporous polymer membranes fabricated via photolithography, for use in a wide range of applications in the personal care, food and drug industries.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100024"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000125/pdfft?md5=a836311ad3b698ebd8427c4ebe27a759&pid=1-s2.0-S2772421222000125-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137290593","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2022.100018
Andrew L. Zydney
The pore constriction (or standard blocking) model is widely used to describe the filtration behavior for a wide range of suspensions/solutions even though the underlying assumption of a uniform reduction in the radius of non-interconnected cylindrical pores is unlikely to be valid in almost any system. This short communication presents an alternative blocking model based on a description of the effective permeability of a fouled membrane accounting for the flow around and under the deposited foulant through the interconnected pore structure of the membrane. The resulting filtration equation gives linear fouling relationships that are very similar to those for the classical pore constriction model, including the slope on a derivative plot, providing a possible justification for the successful use of the pore constriction formalism in describing the flux decline behavior in many membrane systems. In addition, this new blocking model is readily extended to the case where the deposited foulant is permeable to flow. This new composite media blocking model not only provides useful expressions for the rate of flux decline during constant pressure filtration, it also provides insights into the underlying physical mechanisms controlling fouling in membrane systems.
{"title":"Development of a new blocking model for membrane fouling based on a composite media model","authors":"Andrew L. Zydney","doi":"10.1016/j.memlet.2022.100018","DOIUrl":"10.1016/j.memlet.2022.100018","url":null,"abstract":"<div><p>The pore constriction (or standard blocking) model is widely used to describe the filtration behavior for a wide range of suspensions/solutions even though the underlying assumption of a uniform reduction in the radius of non-interconnected cylindrical pores is unlikely to be valid in almost any system. This short communication presents an alternative blocking model based on a description of the effective permeability of a fouled membrane accounting for the flow around and under the deposited foulant through the interconnected pore structure of the membrane. The resulting filtration equation gives linear fouling relationships that are very similar to those for the classical pore constriction model, including the slope on a derivative plot, providing a possible justification for the successful use of the pore constriction formalism in describing the flux decline behavior in many membrane systems. In addition, this new blocking model is readily extended to the case where the deposited foulant is permeable to flow. This new composite media blocking model not only provides useful expressions for the rate of flux decline during constant pressure filtration, it also provides insights into the underlying physical mechanisms controlling fouling in membrane systems.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100018"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277242122200006X/pdfft?md5=188498cf425e22cb1a32cb11b7bedc18&pid=1-s2.0-S277242122200006X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74446120","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2021.100011
Maryam Irani, Nicholas León, Zhongyun Liu, William J. Koros
Gas separation membranes based on glassy polymers often show complex responses to feed compositions, membrane morphologies, and operating conditions. The well-known dual mode sorption and transport models are discussed here as tools to assess plasticization and competition effects in asymmetric morphologies. A framework is illustrated based on these models using polyimide asymmetric hollow fibers. This framework can also be applied to emerging polymer families such as thermally rearranged (TR) and polymers of intrinsic microporosity (PIM), to identify opportunities connected to their innate glassy natures.
{"title":"Overlooked glassy polymer attributes illustrated by asymmetric polyimide hollow fibers","authors":"Maryam Irani, Nicholas León, Zhongyun Liu, William J. Koros","doi":"10.1016/j.memlet.2021.100011","DOIUrl":"10.1016/j.memlet.2021.100011","url":null,"abstract":"<div><p>Gas separation membranes based on glassy polymers often show complex responses to feed compositions, membrane morphologies, and operating conditions. The well-known dual mode sorption and transport models are discussed here as tools to assess plasticization and competition effects in asymmetric morphologies. A framework is illustrated based on these models using polyimide asymmetric hollow fibers. This framework can also be applied to emerging polymer families such as thermally rearranged (TR) and polymers of intrinsic microporosity (PIM), to identify opportunities connected to their innate glassy natures.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100011"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421221000118/pdfft?md5=5dc7368d1a44eac957b5158da9bfb6b1&pid=1-s2.0-S2772421221000118-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79375190","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2022.100023
Anh Q. Nguyen, Luong N. Nguyen, Md Abu Hasan Johir, Huu Hao Ngo, Long D. Nghiem
This study examined membrane fouling and associated microbial taxa in a membrane bioreactor operating at a sub-critical flux condition using next-generation amplicon sequencing. The membrane was operated at a sub-critical flux, thus, fouling was not observed until endogenous decay. The observed fouling could be attributed to endogenous decay which was driven by nutrient deficiency at high sludge age and low food-to-microorganisms ratio (decreasing from 0.15 to 0.09 gBOD/gMLVSS.d). Endogenous decay resulted in a sharp decrease of the number of species and evenness between different species (49.7 and 58.9% compared to the inoculum, respectively). The release of dissolved organic matters and cell debris from endogenous decay as well as the excessive growth of filamentous bacteria, e.g. Thiotrichales were the main contributors to membrane fouling. The relative abundance of Thiotrichales significantly correlated with TMP (Pearson R = 0.996, p-value <0.001), indicating this order's contribution to membrane fouling. Other dominant orders in the mixed liquor after endogenous decay such as Rhizobiales, Burkholderiales, Rhodospirillales and Myxococcales, Flavobacteriales can produce extracellular polymeric substances and aggravating membrane fouling. Fouling layers possess highly similar microbial composition with the mixed liquor, with some filamentous microbial orders, e.g. Corynebacteriales and Oligoflexales showing increased relative abundance by 6.83 and 5.64 folds, respectively.
本研究利用新一代扩增子测序技术检测了在亚临界通量条件下运行的膜生物反应器中的膜污染和相关的微生物类群。膜在亚临界通量下运行,因此,直到内源性衰变才观察到污染。在高污泥龄和低食物微生物比(从0.15 gBOD/gMLVSS.d降至0.09 gBOD/gMLVSS.d)条件下,由于营养缺乏导致内源性腐烂。内源腐烂导致种数和种间均匀度急剧下降(分别为接种量的49.7%和58.9%)。内源性腐烂释放的溶解有机物和细胞碎片以及丝状细菌(如硫代三氯甲烷)的过度生长是膜污染的主要原因。Thiotrichales的相对丰度与TMP显著相关(Pearson R = 0.996, p值<0.001),表明该目对膜污染有贡献。混合液中其他优势目根瘤菌属(Rhizobiales)、Burkholderiales、红螺旋菌属(Rhodospirillales)、黏液球菌属(Myxococcales)、黄杆菌属(Flavobacteriales)等经内源腐烂后可产生胞外聚合物质,加重膜污染。污染层的微生物组成与混合液高度相似,部分丝状菌目如棒状菌目和寡链菌目的相对丰度分别增加了6.83倍和5.64倍。
{"title":"Linking endogenous decay and sludge bulking in the microbial community to membrane fouling at sub-critical flux","authors":"Anh Q. Nguyen, Luong N. Nguyen, Md Abu Hasan Johir, Huu Hao Ngo, Long D. Nghiem","doi":"10.1016/j.memlet.2022.100023","DOIUrl":"10.1016/j.memlet.2022.100023","url":null,"abstract":"<div><p>This study examined membrane fouling and associated microbial taxa in a membrane bioreactor operating at a sub-critical flux condition using next-generation amplicon sequencing. The membrane was operated at a sub-critical flux, thus, fouling was not observed until endogenous decay. The observed fouling could be attributed to endogenous decay which was driven by nutrient deficiency at high sludge age and low food-to-microorganisms ratio (decreasing from 0.15 to 0.09 gBOD/gMLVSS.d). Endogenous decay resulted in a sharp decrease of the number of species and evenness between different species (49.7 and 58.9% compared to the inoculum, respectively). The release of dissolved organic matters and cell debris from endogenous decay as well as the excessive growth of filamentous bacteria, e.g. <em>Thiotrichales</em> were the main contributors to membrane fouling. The relative abundance of <em>Thiotrichales</em> significantly correlated with TMP (Pearson R = 0.996, <em>p</em>-value <0.001), indicating this order's contribution to membrane fouling. Other dominant orders in the mixed liquor after endogenous decay such as <em>Rhizobiales, Burkholderiales, Rhodospirillales</em> and <em>Myxococcales, Flavobacteriales</em> can produce extracellular polymeric substances and aggravating membrane fouling. Fouling layers possess highly similar microbial composition with the mixed liquor, with some filamentous microbial orders, e.g. <em>Corynebacteriales</em> and <em>Oligoflexales</em> showing increased relative abundance by 6.83 and 5.64 folds, respectively.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100023"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000113/pdfft?md5=b8a964da11461eef8665ce601239f1e5&pid=1-s2.0-S2772421222000113-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87428180","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}
Pub Date : 2022-05-01DOI: 10.1016/j.memlet.2022.100021
Yunfei Xing, Yunlong Xue, Dujian Qin, Pengbo Zhao, Pei Li
Although pervaporation (PV) membranes based on crosslinked polyvinyl alcohol (PVA) exhibit high desalination performance, the thermal crosslinking process often takes several hours. Here, we report a microwave assisted method to reduce the crosslinking duration. Moreover, to the PVA crosslinking system, a MOF particle, UIO-66, was added to increase the microwave absorbing efficiency and improve the desalination property. As a result, the PVA crosslinking time decreased to 2 min and the water flux increased by 67% compared with the plain crosslinked PVA membrane.
{"title":"Microwave-induced ultrafast crosslinking of Poly (vinyl alcohol) blended with nanoparticles as wave absorber for pervaporation desalination","authors":"Yunfei Xing, Yunlong Xue, Dujian Qin, Pengbo Zhao, Pei Li","doi":"10.1016/j.memlet.2022.100021","DOIUrl":"10.1016/j.memlet.2022.100021","url":null,"abstract":"<div><p>Although pervaporation (PV) membranes based on crosslinked polyvinyl alcohol (PVA) exhibit high desalination performance, the thermal crosslinking process often takes several hours. Here, we report a microwave assisted method to reduce the crosslinking duration. Moreover, to the PVA crosslinking system, a MOF particle, UIO-66, was added to increase the microwave absorbing efficiency and improve the desalination property. As a result, the PVA crosslinking time decreased to 2 min and the water flux increased by 67% compared with the plain crosslinked PVA membrane.</p></div>","PeriodicalId":100805,"journal":{"name":"Journal of Membrane Science Letters","volume":"2 1","pages":"Article 100021"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772421222000095/pdfft?md5=93f3085409a2bcd177baa3b033d87c3b&pid=1-s2.0-S2772421222000095-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87479614","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}