Pub Date : 2024-09-23DOI: 10.3390/membranes14090202
Luying Chen, Dooli Kim, Wiebe M de Vos
Cellulose, a sustainable raw material, holds great promise as an ideal candidate for membrane materials. In this work, we focused on establishing a low-cost route for producing cellulose microfiltration membranes by adopting a co-solvent system comprising the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) and acetone. The introduction of acetone as a co-solvent into the casting solution allowed control over the viscosity, thereby significantly enhancing the morphologies and filtration performances of the resulting cellulose membranes. Indeed, applying this co-solvent allowed the water permeability to be significantly increased, while maintaining high rejections. Furthermore, the prepared cellulose membrane demonstrated excellent fouling resistance behavior and flux recovery behavior during a challenging oil-in-water emulsion filtration. These results highlight a promising approach to fabricate high-performance cellulose membranes.
{"title":"Enhancing the Separation Performance of Cellulose Membranes Fabricated from 1-Ethyl-3-methylimidazolium Acetate by Introducing Acetone as a Co-Solvent.","authors":"Luying Chen, Dooli Kim, Wiebe M de Vos","doi":"10.3390/membranes14090202","DOIUrl":"https://doi.org/10.3390/membranes14090202","url":null,"abstract":"<p><p>Cellulose, a sustainable raw material, holds great promise as an ideal candidate for membrane materials. In this work, we focused on establishing a low-cost route for producing cellulose microfiltration membranes by adopting a co-solvent system comprising the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) and acetone. The introduction of acetone as a co-solvent into the casting solution allowed control over the viscosity, thereby significantly enhancing the morphologies and filtration performances of the resulting cellulose membranes. Indeed, applying this co-solvent allowed the water permeability to be significantly increased, while maintaining high rejections. Furthermore, the prepared cellulose membrane demonstrated excellent fouling resistance behavior and flux recovery behavior during a challenging oil-in-water emulsion filtration. These results highlight a promising approach to fabricate high-performance cellulose membranes.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11434291/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.3390/membranes14090201
Yanjun Jia, Xiaowen Huo, Lu Gao, Wei Shao, Na Chang
Optimizing the structure of the polyamide (PA) layer to improve the separation performance of PA thin-film composite (TFC) membranes has always been a hot topic in the field of membrane preparation. As novel crystalline materials with high porosity, multi-functional groups, and good compatibility with membrane substrate, metal-organic frameworks (MOFs) have been introduced in the past decade for the modification of the PA structure in order to break through the separation trade-off between permeability and selectivity. This review begins by summarizing the recent progress in the control of MOF-based thin-film nanocomposite (TFN) membrane structures. The review also covers different strategies used for preparing TFN membranes. Additionally, it discusses the mechanisms behind how these strategies regulate the structure and properties of PA. Finally, the design of a competent MOF material that is suitable to reach the requirements for the fabrication of TFN membranes is also discussed. The aim of this paper is to provide key insights into the precise control of TFN-PA structures based on MOFs.
优化聚酰胺(PA)层结构以提高 PA 薄膜复合膜(TFC)的分离性能一直是膜制备领域的热门话题。作为具有高孔隙率、多功能基团以及与膜基质良好相容性的新型晶体材料,金属有机框架(MOFs)在过去十年中被引入到聚酰胺结构的改性中,以突破渗透性和选择性之间的分离权衡。本综述首先总结了在控制基于 MOF 的薄膜纳米复合(TFN)膜结构方面的最新进展。综述还涵盖了用于制备 TFN 膜的不同策略。此外,它还讨论了这些策略如何调节 PA 结构和性能背后的机制。最后,还讨论了如何设计出适合达到 TFN 膜制造要求的 MOF 材料。本文旨在为基于 MOFs 的 TFN-PA 结构的精确控制提供重要见解。
{"title":"Controllable Design of Polyamide Composite Membrane Separation Layer Structures via Metal-Organic Frameworks: A Review.","authors":"Yanjun Jia, Xiaowen Huo, Lu Gao, Wei Shao, Na Chang","doi":"10.3390/membranes14090201","DOIUrl":"https://doi.org/10.3390/membranes14090201","url":null,"abstract":"<p><p>Optimizing the structure of the polyamide (PA) layer to improve the separation performance of PA thin-film composite (TFC) membranes has always been a hot topic in the field of membrane preparation. As novel crystalline materials with high porosity, multi-functional groups, and good compatibility with membrane substrate, metal-organic frameworks (MOFs) have been introduced in the past decade for the modification of the PA structure in order to break through the separation trade-off between permeability and selectivity. This review begins by summarizing the recent progress in the control of MOF-based thin-film nanocomposite (TFN) membrane structures. The review also covers different strategies used for preparing TFN membranes. Additionally, it discusses the mechanisms behind how these strategies regulate the structure and properties of PA. Finally, the design of a competent MOF material that is suitable to reach the requirements for the fabrication of TFN membranes is also discussed. The aim of this paper is to provide key insights into the precise control of TFN-PA structures based on MOFs.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11433959/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-21DOI: 10.3390/membranes14090200
Anastasios J Karabelas, Alexandra Moschona, Konstantinos Merenidis
Effective permeability KP, the ultrafiltration coefficient (KUF), the sieving coefficient (SC), and the loss/permeation of proteins (primarily albumin) are key parameters/specifications characterizing hemofilter (HF) performance. However, there are uncertainties regarding their determination. This work aims (a) to demonstrate that the co-current flow (of blood and dialysate) can lead to beneficial unidirectional filtration (from blood/plasma to dialysate) under a fairly uniform local trans-membrane pressure (TMP), unlike the presently employed counter-current flow; (b) to study the temporal evolution of key HF performance parameters under co-current flow, particularly during the important early stage of hemocatharsis (HC). Experiments with human plasma and BSA solutions in co-current flow mode (for which a fluid mechanical model is developed) show a fairly uniform local/axial TMP, which also improves the local/axial uniformity of protein membrane fouling, particularly under (currently favored) high convective flux operation. Due to incipient membrane fouling, a significant temporal variability/decline in the effective KP is observed, and, in turn, of other parameters (i.e., the Kuf, SC, and permeation/mass flux Mm for albumin and total proteins). A satisfactory correlation of the albumin/protein mass flux Mm with permeability KP is obtained, indicating strong inter-dependence. In conclusion, co-current flow, allowing for a fair local TMP axial uniformity, enables the acquisition of accurate/representative data on the evolution of HF parameters, facilitating their interpretation and correlation. The new results provide a basis for exploring the clinical application of the co-current flow.
{"title":"On the Temporal Evolution of Key Hemofilter Parameters-In Vitro Study under Co-Current Flow.","authors":"Anastasios J Karabelas, Alexandra Moschona, Konstantinos Merenidis","doi":"10.3390/membranes14090200","DOIUrl":"https://doi.org/10.3390/membranes14090200","url":null,"abstract":"<p><p>Effective permeability K<sub>P</sub>, the ultrafiltration coefficient (K<sub>UF</sub>), the sieving coefficient (SC), and the loss/permeation of proteins (primarily albumin) are key parameters/specifications characterizing hemofilter (HF) performance. However, there are uncertainties regarding their determination. This work aims (a) to demonstrate that the co-current flow (of blood and dialysate) can lead to beneficial unidirectional filtration (from blood/plasma to dialysate) under a fairly uniform local trans-membrane pressure (TMP), unlike the presently employed counter-current flow; (b) to study the temporal evolution of key HF performance parameters under co-current flow, particularly during the important early stage of hemocatharsis (HC). Experiments with human plasma and BSA solutions in co-current flow mode (for which a fluid mechanical model is developed) show a fairly uniform local/axial TMP, which also improves the local/axial uniformity of protein membrane fouling, particularly under (currently favored) high convective flux operation. Due to incipient membrane fouling, a significant temporal variability/decline in the effective K<sub>P</sub> is observed, and, in turn, of other parameters (i.e., the Kuf, SC, and permeation/mass flux M<sub>m</sub> for albumin and total proteins). A satisfactory correlation of the albumin/protein mass flux M<sub>m</sub> with permeability K<sub>P</sub> is obtained, indicating strong inter-dependence. In conclusion, co-current flow, allowing for a fair local TMP axial uniformity, enables the acquisition of accurate/representative data on the evolution of HF parameters, facilitating their interpretation and correlation. The new results provide a basis for exploring the clinical application of the co-current flow.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11434192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.3390/membranes14090199
Mohamed Echakouri, Amr Henni, Amgad Salama
This comprehensive study looks at how operational conditions affect the performance of a novel seven-channel titania ceramic ultrafiltration membrane for the treatment of produced water. A full factorial design experiment (23) was conducted to study the effect of the cross-flow operating factors on the membrane permeate flux decline and the overall permeate volume. Eleven experimental runs were performed for three important process operating variables: transmembrane pressure (TMP), crossflow velocity (CFV), and filtration time (FT). Steady final membrane fluxes and permeate volumes were recorded for each experimental run. Under the optimized conditions (1.5 bar, 1 m/s, and 2 h), the membrane performance index demonstrated an oil rejection rate of 99%, a flux of 297 L/m2·h (LMH), a 38% overall initial flux decline, and a total permeate volume of 8.14 L. The regression models used for the steady-state membrane permeate flux decline and overall permeate volume led to the highest goodness of fit to the experimental data with a correlation coefficient of 0.999. A Multiple Linear Regression method and an Artificial Neural Network approach were also employed to model the experimental membrane permeate flux decline and analyze the impact of the operating conditions on membrane performance. The predictions of the Gaussian regression and the Levenberg-Marquardt backpropagation method were validated with a determination coefficient of 99% and a Mean Square Error of 0.07.
{"title":"A Novel Modeling Optimization Approach for a Seven-Channel Titania Ceramic Membrane in an Oily Wastewater Filtration System Based on Experimentation, Full Factorial Design, and Machine Learning.","authors":"Mohamed Echakouri, Amr Henni, Amgad Salama","doi":"10.3390/membranes14090199","DOIUrl":"https://doi.org/10.3390/membranes14090199","url":null,"abstract":"<p><p>This comprehensive study looks at how operational conditions affect the performance of a novel seven-channel titania ceramic ultrafiltration membrane for the treatment of produced water. A full factorial design experiment (2<sup>3</sup>) was conducted to study the effect of the cross-flow operating factors on the membrane permeate flux decline and the overall permeate volume. Eleven experimental runs were performed for three important process operating variables: transmembrane pressure (TMP), crossflow velocity (CFV), and filtration time (FT). Steady final membrane fluxes and permeate volumes were recorded for each experimental run. Under the optimized conditions (1.5 bar, 1 m/s, and 2 h), the membrane performance index demonstrated an oil rejection rate of 99%, a flux of 297 L/m<sup>2</sup>·h (LMH), a 38% overall initial flux decline, and a total permeate volume of 8.14 L. The regression models used for the steady-state membrane permeate flux decline and overall permeate volume led to the highest goodness of fit to the experimental data with a correlation coefficient of 0.999. A Multiple Linear Regression method and an Artificial Neural Network approach were also employed to model the experimental membrane permeate flux decline and analyze the impact of the operating conditions on membrane performance. The predictions of the Gaussian regression and the Levenberg-Marquardt backpropagation method were validated with a determination coefficient of 99% and a Mean Square Error of 0.07.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11433700/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.3390/membranes14090198
Temitope Q Aminu, Hamid Fattahi Juybari, David M Warsinger, David F Bahr
Filtration membranes coated in metals such as copper have dramatically improved biofouling resistance and pathogen destruction. However, existing coating methods on polymer membranes impair membrane performance, lack uniformity, and may detach from their substrate, thus contaminating the permeate. To solve these challenges, we developed the first electroless deposition protocol to immobilize copper nanoparticles on electrospun polyacrylonitrile (PAN) fibers for the design of antimicrobial membranes. The deposition was facilitated by prior silver seeding. Distinct mats with average fiber diameters of 232 ± 36 nm, 727 ± 148 nm and 1017 ± 80 nm were evaluated for filtration performance. Well-dispersed copper nanoparticles were conformal to the fibers, preserving the open-cell architecture of the membranes. The copper particle sizes ranged from 20 to 140 nm. Infrared spectroscopy revealed the PAN fiber mats' relative chemical stability/resistance to the copper metallization process. In addition, the classical cyclization of the cyano functional group in PAN was observed. For model polystyrene beads with average sizes of 3 μm, Cu NP-PAN fiber mats had high water flux and separation efficiency with negligible loss of Cu NP from the fibers during flow testing. Fiber size increased flux and somewhat decreased separation efficiency, though the efficiency values were still high.
涂有铜等金属的过滤膜大大提高了抗生物污染和病原体破坏的能力。然而,现有的聚合物膜涂覆方法会损害膜的性能,缺乏均匀性,而且可能会从基材上脱落,从而污染渗透液。为了解决这些难题,我们开发了首个无电解沉积方案,将纳米铜粒子固定在电纺聚丙烯腈(PAN)纤维上,用于设计抗菌膜。沉积过程通过事先播种银来实现。对平均纤维直径为 232 ± 36 nm、727 ± 148 nm 和 1017 ± 80 nm 的不同纤维毡进行了过滤性能评估。分散良好的纳米铜粒子与纤维贴合,保持了膜的开孔结构。铜颗粒的大小在 20 纳米到 140 纳米之间。红外光谱显示了 PAN 纤维毡对铜金属化过程的相对化学稳定性/耐受性。此外,还观察到 PAN 中氰基官能团的经典环化现象。对于平均尺寸为 3 μm 的模型聚苯乙烯珠,Cu NP-PAN 纤维毡具有较高的水通量和分离效率,在流动测试过程中,纤维中 Cu NP 的损失可以忽略不计。纤维尺寸增加了通量,在一定程度上降低了分离效率,尽管效率值仍然很高。
{"title":"Electroless Deposition for Robust and Uniform Copper Nanoparticles on Electrospun Polyacrylonitrile (PAN) Microfiltration Membranes.","authors":"Temitope Q Aminu, Hamid Fattahi Juybari, David M Warsinger, David F Bahr","doi":"10.3390/membranes14090198","DOIUrl":"https://doi.org/10.3390/membranes14090198","url":null,"abstract":"<p><p>Filtration membranes coated in metals such as copper have dramatically improved biofouling resistance and pathogen destruction. However, existing coating methods on polymer membranes impair membrane performance, lack uniformity, and may detach from their substrate, thus contaminating the permeate. To solve these challenges, we developed the first electroless deposition protocol to immobilize copper nanoparticles on electrospun polyacrylonitrile (PAN) fibers for the design of antimicrobial membranes. The deposition was facilitated by prior silver seeding. Distinct mats with average fiber diameters of 232 ± 36 nm, 727 ± 148 nm and 1017 ± 80 nm were evaluated for filtration performance. Well-dispersed copper nanoparticles were conformal to the fibers, preserving the open-cell architecture of the membranes. The copper particle sizes ranged from 20 to 140 nm. Infrared spectroscopy revealed the PAN fiber mats' relative chemical stability/resistance to the copper metallization process. In addition, the classical cyclization of the cyano functional group in PAN was observed. For model polystyrene beads with average sizes of 3 μm, Cu NP-PAN fiber mats had high water flux and separation efficiency with negligible loss of Cu NP from the fibers during flow testing. Fiber size increased flux and somewhat decreased separation efficiency, though the efficiency values were still high.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11434320/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the impact of compression force on stack performance and the effect of testing conditions on sensitivity of stack performance. It explores the variation of assembly force on the pressure distribution at different positions in a 1 kW proton exchange membrane fuel cell stack. Polarization curves and high-frequency resistance (HFR) changes of the stack were measured under different assembly forces, and the optimal assembly force of the stack was determined using the average single-cell voltage (HFR-free). The sensitivity of testing conditions was optimized, and the optimum test parameters at different current densities were identified within the selected range. Stack stability was tested at different current densities using the optimized test conditions, and the sensitivity of test conditions was verified by the fluctuation amplitude of single cell voltage and internal impedance.
{"title":"Sensitivity and Stability Study of Test Conditions for a 1 kW Proton Exchange Membrane Fuel Cell Stack.","authors":"Peng Xu, Yingmin Yi, Weijie Wang, Meng Xie, Yiwei Yuan","doi":"10.3390/membranes14090197","DOIUrl":"https://doi.org/10.3390/membranes14090197","url":null,"abstract":"<p><p>This study investigates the impact of compression force on stack performance and the effect of testing conditions on sensitivity of stack performance. It explores the variation of assembly force on the pressure distribution at different positions in a 1 kW proton exchange membrane fuel cell stack. Polarization curves and high-frequency resistance (HFR) changes of the stack were measured under different assembly forces, and the optimal assembly force of the stack was determined using the average single-cell voltage (HFR-free). The sensitivity of testing conditions was optimized, and the optimum test parameters at different current densities were identified within the selected range. Stack stability was tested at different current densities using the optimized test conditions, and the sensitivity of test conditions was verified by the fluctuation amplitude of single cell voltage and internal impedance.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11433875/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wastewater treatment plants produce high quantities of excess sludge. However, traditional sludge dewatering technology has high energy consumption and occupies a large area. Dead-end forward osmosis (DEFO) is an efficient and energy-saving deep dewatering technology for sludge. In this study, the reverse osmosis of salt ions in the draw solution was used to change the sludge cake structure and further reduce its moisture content in cake by releasing the bound water in cell. Three salts, NaCl, KCl, and CaCl2, were added to the excess sludge feed solution to explore the roles of the reverse osmosis of draw solutes in DEFO. When the added quantities of NaCl and CaCl2 were 15 and 10 mM, respectively, the moisture content of the sludge after dewatering decreased from 98.1% to 79.7% and 67.3%, respectively. However, KCl did not improve the sludge dewatering performance because of the "high K and low Na" phenomenon in biological cells. The water flux increased significantly for the binary draw solute involving NaCl and CaCl2 compared to the single draw solute. The extracellular polymer substances in the sludge changed the structure of the filter cake to improve the formation of water channels and decrease osmosis resistance, resulting in an increase in sludge dewatering efficiency. These findings provide support for improving the sludge dewatering performance of DEFO.
污水处理厂会产生大量过剩污泥。然而,传统的污泥脱水技术能耗高、占地面积大。死端正向渗透(DEFO)是一种高效节能的污泥深度脱水技术。本研究利用汲取液中盐离子的反渗透作用改变污泥饼结构,通过释放细胞中的结合水进一步降低污泥饼中的含水率。在过量的污泥进料溶液中加入 NaCl、KCl 和 CaCl2 三种盐,以探讨汲取溶质反渗透在 DEFO 中的作用。当 NaCl 和 CaCl2 的添加量分别为 15 mM 和 10 mM 时,脱水后污泥的含水率分别从 98.1% 降至 79.7% 和 67.3%。然而,由于生物细胞中存在 "高 K 低 Na "现象,KCl 并没有改善污泥脱水性能。与单一汲取溶质相比,NaCl 和 CaCl2 的二元汲取溶质的水通量明显增加。污泥中的细胞外高分子物质改变了滤饼的结构,改善了水通道的形成,降低了渗透阻力,从而提高了污泥脱水效率。这些发现为提高 DEFO 的污泥脱水性能提供了支持。
{"title":"Reverse Solute Diffusion Enhances Sludge Dewatering in Dead-End Forward Osmosis.","authors":"Da-Qi Cao, Shi-Cheng Lei, Hui Liu, Yan Jin, Yun-Feng Wu, Yuehua Cui, Rongling Wu","doi":"10.3390/membranes14090196","DOIUrl":"https://doi.org/10.3390/membranes14090196","url":null,"abstract":"<p><p>Wastewater treatment plants produce high quantities of excess sludge. However, traditional sludge dewatering technology has high energy consumption and occupies a large area. Dead-end forward osmosis (DEFO) is an efficient and energy-saving deep dewatering technology for sludge. In this study, the reverse osmosis of salt ions in the draw solution was used to change the sludge cake structure and further reduce its moisture content in cake by releasing the bound water in cell. Three salts, NaCl, KCl, and CaCl<sub>2</sub>, were added to the excess sludge feed solution to explore the roles of the reverse osmosis of draw solutes in DEFO. When the added quantities of NaCl and CaCl<sub>2</sub> were 15 and 10 mM, respectively, the moisture content of the sludge after dewatering decreased from 98.1% to 79.7% and 67.3%, respectively. However, KCl did not improve the sludge dewatering performance because of the \"high K and low Na\" phenomenon in biological cells. The water flux increased significantly for the binary draw solute involving NaCl and CaCl<sub>2</sub> compared to the single draw solute. The extracellular polymer substances in the sludge changed the structure of the filter cake to improve the formation of water channels and decrease osmosis resistance, resulting in an increase in sludge dewatering efficiency. These findings provide support for improving the sludge dewatering performance of DEFO.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11433884/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.3390/membranes14090195
Xiancan Yuan, Zhongrui Lu, Xiaoyang Jia, Zhuoran Yang, Jian Wang, Xiong Wang, Jun Lin, Shaojian He
Phosphotungstic acid (HPW) can retain water in proton exchange membranes to increase proton conductivity; however, its water-soluble nature limits further application. In this work, we combined HPW and graphitic carbon nitride (g-C3N4) via sintering to prepare water-insoluble hybrids (HWN), where HPW was chemically linked to g-C3N4 to fix HPW. Then, HWN fillers were added to a sulfonated polyether ether ketone (SPEEK) matrix to prepare composite membranes. The conductivity of the composite membrane with 10 wt% HWN is up to 0.066 S cm-1 at room temperature, which is 53% higher than that of the SPEEK control membrane (0.043 S cm-1). The composite membrane also showed stable proton conductivity after being immersed in water for 2000 h. Therefore, our study demonstrates that preparing water-insoluble nanofillers containing HPW components through sintering is a promising approach.
磷钨酸(HPW)可以在质子交换膜中保留水分,从而提高质子传导性;然而,其水溶性限制了进一步的应用。在这项工作中,我们通过烧结将磷钨酸和石墨氮化碳(g-C3N4)结合起来,制备了水不溶性杂化物(HWN),其中磷钨酸与 g-C3N4 通过化学连接固定了磷钨酸。然后,将 HWN 填料添加到磺化聚醚醚酮(SPEEK)基质中,制备出复合膜。含有 10 wt% HWN 的复合膜在室温下的电导率高达 0.066 S cm-1,比 SPEEK 对照膜(0.043 S cm-1)高出 53%。因此,我们的研究表明,通过烧结制备含有 HPW 成分的水不溶性纳米填料是一种很有前景的方法。
{"title":"Utilization of Water-Insoluble Carbon Nitride-Phosphotungstic Acid Hybrids in Composite Proton Exchange Membranes.","authors":"Xiancan Yuan, Zhongrui Lu, Xiaoyang Jia, Zhuoran Yang, Jian Wang, Xiong Wang, Jun Lin, Shaojian He","doi":"10.3390/membranes14090195","DOIUrl":"https://doi.org/10.3390/membranes14090195","url":null,"abstract":"<p><p>Phosphotungstic acid (HPW) can retain water in proton exchange membranes to increase proton conductivity; however, its water-soluble nature limits further application. In this work, we combined HPW and graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>) via sintering to prepare water-insoluble hybrids (HWN), where HPW was chemically linked to g-C<sub>3</sub>N<sub>4</sub> to fix HPW. Then, HWN fillers were added to a sulfonated polyether ether ketone (SPEEK) matrix to prepare composite membranes. The conductivity of the composite membrane with 10 wt% HWN is up to 0.066 S cm<sup>-1</sup> at room temperature, which is 53% higher than that of the SPEEK control membrane (0.043 S cm<sup>-1</sup>). The composite membrane also showed stable proton conductivity after being immersed in water for 2000 h. Therefore, our study demonstrates that preparing water-insoluble nanofillers containing HPW components through sintering is a promising approach.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11433968/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.3390/membranes14090194
Deepraj Sarmah, Scott M Husson
Adeno-associated viral vectors (AAVs) are the predominant viral vectors used for gene therapy applications. A significant challenge in obtaining effective doses is removing non-therapeutic empty viral capsids lacking DNA cargo. Current methods for separating full (gene-containing) and empty capsids are challenging to scale, produce low product yields, are slow, and are difficult to operationalize for continuous biomanufacturing. This communication demonstrates the feasibility of separating full and empty capsids by ultrafiltration. Separation performance was quantified by measuring the sieving coefficients for full and empty capsids using ELISA, qPCR, and an infectivity assay based on the live cell imaging of green fluorescent protein expression. We demonstrated that polycarbonate track-etched membranes with a pore size of 30 nm selectively permeated empty capsids to full capsids, with a high recovery yield (89%) for full capsids. The average sieving coefficients of full and empty capsids obtained through ELISA/qPCR were calculated as 0.25 and 0.49, indicating that empty capsids were about twice as permeable as full capsids. Establishing ultrafiltration as a viable unit operation for separating full and empty AAV capsids has implications for developing the scale-free continuous purification of AAVs.
{"title":"A Novel Method for Separating Full and Empty Adeno-Associated Viral Capsids Using Ultrafiltration.","authors":"Deepraj Sarmah, Scott M Husson","doi":"10.3390/membranes14090194","DOIUrl":"https://doi.org/10.3390/membranes14090194","url":null,"abstract":"<p><p>Adeno-associated viral vectors (AAVs) are the predominant viral vectors used for gene therapy applications. A significant challenge in obtaining effective doses is removing non-therapeutic empty viral capsids lacking DNA cargo. Current methods for separating full (gene-containing) and empty capsids are challenging to scale, produce low product yields, are slow, and are difficult to operationalize for continuous biomanufacturing. This communication demonstrates the feasibility of separating full and empty capsids by ultrafiltration. Separation performance was quantified by measuring the sieving coefficients for full and empty capsids using ELISA, qPCR, and an infectivity assay based on the live cell imaging of green fluorescent protein expression. We demonstrated that polycarbonate track-etched membranes with a pore size of 30 nm selectively permeated empty capsids to full capsids, with a high recovery yield (89%) for full capsids. The average sieving coefficients of full and empty capsids obtained through ELISA/qPCR were calculated as 0.25 and 0.49, indicating that empty capsids were about twice as permeable as full capsids. Establishing ultrafiltration as a viable unit operation for separating full and empty AAV capsids has implications for developing the scale-free continuous purification of AAVs.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11434191/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.3390/membranes14090193
Alexandra Papuc, Simion Bran, Marioara Moldovan, Ondine Lucaciu, Gabriel Armencea, Grigore Baciut, Cristian Dinu, Florin Onișor, Winfried Kretschmer, Mihaela Baciut
The aim of this study was to analyze published works that investigate the in vivo bone regeneration capacity of polymeric membranes loaded with active substances and growth factors. This scoping review's purpose was to highlight the histological and radiological interpretation of the locally produced effects of the polymer membranes studied so far. For the selection of the articles, a search was made in the PubMed and ScienceDirect databases, according to the PRISMA algorithm, for research/clinical trial type studies. The search strategy was represented by the formula "((biodegradable scaffolds AND critical bone defect) OR (polymers AND mechanical properties) OR (3Dmaterials AND cytotoxicity) AND bone tissue regeneration)" for the PubMed database and "((biodegradable scaffolds AND polymers) OR (polymers AND critical bone defects) OR (biodegradable scaffolds AND mechanical properties) AND bone tissue regeneration)" for the ScienceDirect database. Ethical approval was not required. Eligibility criteria included eight clinical studies published between 2018 and 2023. Our analysis showed that polymer membranes that met most histopathological criteria also produced the most remarkable results observed radiologically. The top effective scaffolds were those containing active macromolecules released conditionally and staged. The PLGA and polycaprolactone scaffolds were found in this category; they granted a marked increase in bone density and improvement of osteoinduction. But, regardless of the membrane composition, all membranes implanted in created bone defects induced an inflammatory response in the first phase.
{"title":"How Is Bone Regeneration Influenced by Polymer Membranes? Insight into the Histological and Radiological Point of View in the Literature.","authors":"Alexandra Papuc, Simion Bran, Marioara Moldovan, Ondine Lucaciu, Gabriel Armencea, Grigore Baciut, Cristian Dinu, Florin Onișor, Winfried Kretschmer, Mihaela Baciut","doi":"10.3390/membranes14090193","DOIUrl":"https://doi.org/10.3390/membranes14090193","url":null,"abstract":"<p><p>The aim of this study was to analyze published works that investigate the in vivo bone regeneration capacity of polymeric membranes loaded with active substances and growth factors. This scoping review's purpose was to highlight the histological and radiological interpretation of the locally produced effects of the polymer membranes studied so far. For the selection of the articles, a search was made in the PubMed and ScienceDirect databases, according to the PRISMA algorithm, for research/clinical trial type studies. The search strategy was represented by the formula \"((biodegradable scaffolds AND critical bone defect) OR (polymers AND mechanical properties) OR (3Dmaterials AND cytotoxicity) AND bone tissue regeneration)\" for the PubMed database and \"((biodegradable scaffolds AND polymers) OR (polymers AND critical bone defects) OR (biodegradable scaffolds AND mechanical properties) AND bone tissue regeneration)\" for the ScienceDirect database. Ethical approval was not required. Eligibility criteria included eight clinical studies published between 2018 and 2023. Our analysis showed that polymer membranes that met most histopathological criteria also produced the most remarkable results observed radiologically. The top effective scaffolds were those containing active macromolecules released conditionally and staged. The PLGA and polycaprolactone scaffolds were found in this category; they granted a marked increase in bone density and improvement of osteoinduction. But, regardless of the membrane composition, all membranes implanted in created bone defects induced an inflammatory response in the first phase.</p>","PeriodicalId":18410,"journal":{"name":"Membranes","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11434093/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142336465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}