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Hybrid membranes combining graphene oxide (GO) and silicon dioxide (SiO 2) were successfully developed for pervaporation desalination using porous zircon tube substrates. These GO/SiO 2 membranes were carefully designed by adjusting the amount of GO and the pH levels during the dip-coating process on the zircon tube surface. The study aimed to investigate how varying amounts of GO and pH levels affect the membranes' properties and desalination performance. The results indicate that raising the pH level decreases the membranes' hydrophilicity and enhances their stability. Conversely, increasing the amount of GO increases the membranes' hydrophilicity and reduces their pore size. Higher pH levels and GO amounts resulted in better salt rejection but lower water flux. Among the tested membranes, GS-6 (0.3 % GO/SiO 2 , pH 6) achieved the highest salt rejection rate of 99.96 % at 30 °C with a 1 % NaCl feed concentration. In contrast, GS-1 (0.1 % GO/SiO 2 , pH 4) showed the highest water flux of 8.54 kg m−2 h−1 at 60 °C with the same feed concentration. Increasing the temperature led to decreased salt rejection but increased water flux. Additionally, higher feed concentrations lowered both salt rejection and water flux. [ABSTRACT FROM AUTHOR]

AbstractThe treatment of industrial wastewater is crucial for recovering water of high purity, especially considering its significance in mitigating environmental pollution and ensuring sustainable water resources. This study focuses on the purification of industrial wastewater, emphasizing the separation of tetrahydrofuran (THF) from aqueous solutions using membrane-based techniques. Composite membranes incorporating magnetic nanomaterial (magnetite) within a sodium alginate matrix were synthesized and evaluated for their effectiveness in purifying water from THF mixtures. Both Pervaporation (PV) and Vapor Permeation (VP) processes were employed, with thorough analysis conducted on the impact of magnetite content on permeate purity. The study identified optimal magnetite content for industrial wastewater treatment and developed a new membrane composition based on these findings. The VP process’s performance was evaluated by determining the permeation flux and separation factor. The highest separation factor of 460 was obtained for an 80% wt. THF-water solution in the VP process. Using these findings, the optimal magnetite content for industrial wastewater treatment was identified, and a new membrane composition was developed. The activation energies for the permeation of THF through the NaAlg-Fe20 membrane were found to be 10.50 kcal/mol and 7 kcal/mol for the VP and PV processes, respectively. [ABSTRACT FROM AUTHOR]

This study assesses the gas and water vapor permeance of PIM-derivative thin-film composite (TFC) membranes using pervaporation and "pressure increase" methods, and provides a comparative view of "time lag" measurements of thick films obtained from our previous work. In this study, TFC membranes were prepared using PIM-1 and homopolymers that were modified with different side groups to explore their effects on gas and water vapor transport. Rigid and bulky aliphatic groups were used to increase the polymer's free volume and were evaluated for their impact on both gas and water transport. Aromatic side groups were specifically employed to assess water affinity. The permeance of CO2, H2, CH4 and water vapor through these membranes was analyzed using the 'pressure increase' method to determine the modifications' influence on transport efficiency and interaction with water molecules. Over a 20 h period, the aging and the permeance of the TFC membranes were analyzed using this method. In parallel, pervaporation experiments were conducted on samples taken independently from the same membrane roll to assess water flux, with particular attention paid to the liquid form on the feed side. The significantly higher water vapor transport rates observed in pervaporation experiments compared to those using the "pressure increase" method underline the efficiency of pervaporation. This efficiency suggests that membranes designed for pervaporation can serve as effective alternatives to conventional porous membranes used in distillation applications. Additionally, incorporating "time lag" results from a pioneering study into the comparison revealed that the trends observed in "time lag" and pervaporation results exhibited similar trends, whereas "pressure increase" data showed a different development. This discrepancy is attributed to the state of the polymer, which varies significantly depending on the operating conditions. [ABSTRACT FROM AUTHOR]

A high‐quality filler within mixed matrix membranes, coupled with uniform dispersity, endows a high‐efficiency transfer pathway for the significant improvement on separation performance. In this work, a zeolite‐typed MCM‐22 filler is reported that is doped into polydimethylsiloxane (PDMS) matrix by ultrafast photo‐curing technique. The unique structure of nanosheets assembly layer by layer endows the continuous transfer channels towards penetrate molecules because of the inter‐connective nanosheets within PDMS matrix. Furthermore, an ultrafast freezing effect produced by fast photo‐curing is used to overcome the key issue, namely filler aggregation, and further eliminates defects. When pervaporative separating a 5 wt% ethanol aqueous solution, the resulting MCM‐22/PDMS membrane exhibits an excellent membrane flux of 1486 g m−2 h−1 with an ethanol separation factor of 10.2. Considering a biobased route for ethanol production, the gas stripping and vapor permeation through this membrane also shows a great enrichment performance, and the concentrated ethanol is up to 65.6 wt%. Overall, this MCM‐22/PDMS membrane shows a high separation ability for ethanol benefited from a unique structure deign of fillers and ultrafast curing speed of PDMS, and has a great potential for bioethanol separation from cellulosic ethanol fermentation. [ABSTRACT FROM AUTHOR]

Butanol as a biofuel, can be produced by ABE (acetone-butanol-ethanol) fermentation. Pervaporation is a promising process, especially for the separation of biofuels from aqueous mixtures such as ABE mixtures which consists of 3:6:1 ratio of ABE solvents and water around 97%. In this study, ionic liquid-based membranes were developed for the recovery of butanol from aqueous mixtures. The active layer providing the selectivity was formed by using polydimethylsiloxane (PDMS) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) ionic liquid (IL). Porous polyvinylidenefluoride (PVDF) and polytetrafluoroethylene (PTFE) films were used as the support layers. Two different types of membranes were prepared, in which IL was mixed into PDMS and cast as a thin film on the support layer, and IL was impregnated into the pores of the support layers. The effects of feed concentration and temperature on separation performance were investigated. In addition, the membranes were prepared with and without IL, and the effect of IL on membrane performance was investigated. In general, an increase in flux and selectivity values ​​was observed with the addition of IL in PDMS. Butanol selectivities in pervaporation experiments with different process parameters were found between 24.7 and 61.3 when PTFE support layer was used and between 22.5 and 48.6 when PVDF support layer was used. Especially with the use of IL in the membrane, the fluxes increased 2.5-5 times, resulting in a significant increase in fluxes. As a result, it has been shown that PDMS+IL/PVDF and PDMS+IL/PTFE membranes can be used for effective butanol recovery by pervaporation. [ABSTRACT FROM AUTHOR]

Membrane osmotic distillation (OD) is applied in this work for the partial dealcoholization of beer (5.2 v/v% alcohol content) to diminish its ethanol content by around 50% giving rise to a low alcohol beer. A compromise is sought between the low alcoholic degree achieved and beer sensory properties. Moreover, the feasibility of the membrane OD process intensification is studied thanks to its combination with membrane pervaporation (PV). Two successive PV stages, one hydrophobic and the other hydrophilic, allow the production of recycled water (with less than 0.5 wt% ethanol) for the membrane OD operation and bioethanol (99% ethanol) as valuable byproduct. [ABSTRACT FROM AUTHOR]

Non-alcoholic beer is becoming more and more popular every year. Due to the high demand for such drinks, numerous breweries decided to produce non-alcoholic beer. There are various methods to create a beer with a reduced alcohol content. Among them are biological methods influencing the biochemistry of the brewing process and physical methods focused on removing ethanol from ready beer. Thus far, the most popular methods are vacuum rectification and reverse osmosis. This work evaluated another method called pervaporation for non-alcoholic beer production. During the study, low-alcohol beer (0.58 vol.%) was achieved from standard beer (3.62 vol.%) using pervaporation. The colour of the product remained unchanged at level 7 EBC. The concentration of ferulic acid decreased from 11.5 to 9.1 mg/dm3, and maltol was concentrated, reaching a concentration of 38 mg/dm3 in the final retentate during a 5 h process. [ABSTRACT FROM AUTHOR]

The effect of carbonization temperature on thin-film carbon membranes prepared by carbonization of sorbitol and intended for pervaporation desalination was investigated. Thermal properties, functional groups, phase structures, and surface morphology of the prepared carbon and membrane materials were studied by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy, x-ray diffraction and scanning electron microscope, respectively, while the membrane performance was evaluated in the pervaporation process. At 400 °C, the TGA revealed a drastic decrease in the sorbitol mass, which correlated with the loss of hydroxyl groups, leaving C–C and C=C groups as carbon materials. Regardless of the applied carbonization temperature, all carbon materials have an amorphous phase; carbonization temperature affects the surface morphology of the carbon membrane, both surface contours and layer thickness, which is directly proportional to desalination performance. The membrane performance was investigated using 1 wt.%, 3.5%, and 7% NaCl solutions at different feed temperatures. Higher carbonization temperatures produce membranes with superior separation performance. The sorbitol-derived carbon membrane carbonized at 350 °C with a concentration of 3.5% and feed solution temperature of 60 °C yielded the best desalination performance, where salt rejection was > 99.9% and water flux was 17.35 kg m−2 h−1. The carbon membrane exhibited excellent salt rejection, close to 100%. It can maintain the separation performance for up to 100 working hours, indicating that the carbon membrane from the sorbitol precursor has the potential to be utilized as a long-term pervaporating membrane. [ABSTRACT FROM AUTHOR]

Pervaporation (PV) is a promising membrane‐based technology for dehydrating alcohols and separation of close‐boiling liquids. Poly(styrene sulfonic acid‐co‐maleic acid) (PSSAMA) crosslinked sodium alginate (NaAlg) membrane was developed, and was then modified by varying the mass% of sulfonated graphite oxide (SGO). Physicochemical properties of the resulting membranes were assessed using FTIR, WXRD, TGA, DSC, and SEM. The pervaporation study was carried out to assess membrane performance in dehydrating isopropanol. The membrane with 16 mass% of SGO exhibited the highest separation factor of 6025 and flux of 14.66 × 10−2 kg m−2 h−1 at 30°C for 10 mass% of water in the feed and were able to break the water–isopropanol azeotropic point. The activation energy for water permeation (Epw) was lower than that of isopropanol permeation (EIPA), indicating the high separation ability. Activation energies for total permeation (EP) and total diffusion (ED) ranged from 12.42 to 49.13 and 12.99 to 54.42 kJ mol−1, respectively. Negative enthalpy values (ΔHs) suggested Langmuir's sorption predominance for all membranes. Highlights: The SGO incorporated crosslinked NaAlg composite membranes were prepared.The membrane containing 16 mass% of SGO showed the highest water uptake.Membrane with 16 mass% of SGO showed the highest flux and separation factor.All composite membranes showed excellent thermal and mechanical stability.Membrane with 16 mass% of SGO demonstrated excellent PV performance. [ABSTRACT FROM AUTHOR]

This study investigated the enhancement in bioethanol recovery from mixed matrix membranes (MMMs) by functionalizing zeolite framework-8 (ZIF-8) with imidazolate. This study focused on the separation of ethanol from low-concentration ethanol/water mixtures (typical post-fermentation concentrations of 5–10 wt%). Specifically, ZIF-8 was modified by the shell–ligand exchange reaction (SLER) with 5,6-dimethylbenzimidazole (DMBIM), resulting in ZIF-8-DMBIM particles with improved hydrophobicity, organophilicity, larger size, and adjustable pore size. These particles were incorporated into a PEBAX 2533 matrix to produce ZIF-8-DMBIM/PEBAX MMMs using a dilution blending method. The resulting membranes showed significant performance enhancement: 8 wt% ZIF-8-DMBIM loading achieved a total flux of 308 g/m2·h and a separation factor of 16.03, which was a 36.8% increase in flux and 176.4% increase in separation factor compared with the original PEBAX membrane. In addition, performance remained stable during a 130 h cycling test. These improvements are attributed to the enhanced compatibility and dispersion of ZIF-8-DMBIM in the PEBAX matrix. In conclusion, the evaluation of nanofiller content, feed concentration, operating temperature, and membrane stability confirmed that ZIF-8-DMBIM/PEBAX MMM is ideal for ethanol recovery in primary bioethanol concentration processes. [ABSTRACT FROM AUTHOR]

As a promising wastewater treatment technology, ultrafiltration membranes face challenges related to fouling and flux reduction. To enhance these membranes, various strategies have been explored. Among them, the incorporation of nano-activated carbon (nAC) powder has emerged as an effective method. In this study, composite polysulfone (PSF) ultrafiltration membranes were fabricated using nAC powder at concentrations ranging from 0 to 8 wt.%. These membranes underwent comprehensive investigation, including assessments of membrane morphology, hydrophilicity, pure water flux, equilibrium water content, porosity, average pore size, and protein separation. The addition of activated carbon improved several desirable properties. Specifically, the hydrophilicity of the PSF membranes was enhanced, with the contact angle reduced from 69° to 58° for 8 wt.% of nAC composite membranes compared to the pristine PSF membrane. Furthermore, the water flux test revealed that 6 wt.% activated carbon-based membranes exhibited the highest flux, with a nearly 3 times improvement at 2 bar. Importantly, this enhancement did not compromise the protein rejection. Additionally, the introduction of nAC had a significant effect on the membrane's pore size by improving lysozyme rejection up to 40%. Overall, these findings will guide the selection of the optimal concentration of nAC for PSF ultrafiltration membranes. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AbstractThe membrane, a core element in pervaporation technology, is of utmost importance for its advancement. Membrane modification is one of the most effective means of achieving an efficient membrane, which is crucial for the progress of this technology. High selectivity and flux can be achieved by modifying the membrane or membrane polymer by changing properties such as the surface energy, surface roughness, arrangement of polymer chains, and polymer network. Hence, recent publications on various methods for modifying polymeric membranes in the context of pervaporation applications are meticulously summarized and categorized, and aging and fouling factors have been mentioned in this review. This evaluation provided a thorough summary of the benefits and drawbacks of each method. Among the numerous techniques, mixing, crosslinking, and surface modification are commonly employed to modify polymeric membranes specifically tailored for pervaporation processes. [ABSTRACT FROM AUTHOR]

This paper mainly reviews the research status of PV technology in the separation of organic mixtures in recent years. The main research achievements of PV technology in the separation of polar/non-polar mixture, aromatic/alkane, isomeric, and removal of sulfide in gasoline are described in detail. At the same time, we look forward to the development direction of PV technology in the field of separating organic mixtures and provide a reference for the subsequent research on the separation of organic mixtures by PV technology. [ABSTRACT FROM AUTHOR]

Pervaporation has been considered a promising technique in the recovery of organic matter in low concentrations. Developing new and efficient pervaporation membrane materials remains the main challenge. In this study, the biodegradable poly (butylene adipate‐terephthalate) (PBAT) membrane was used to recover aniline by pervaporation for the first time. The PBAT membrane showed a good pervaporation performance due to its unique affinity with aniline by the surface adsorption energy calculations. When the aniline concentration in the feed solution was 0.4 wt%, the separation factor of the PBAT membrane exceeded 80. Besides, the results showed that the flux rose with the aniline concentration increasing, which was because of the incremental free volume of PBAT membrane. Moreover, the H‐bond length between aniline and PBAT (1.947 Å) was shorter than that between water and PBAT (2.091 Å) according to the density functional theory (DFT) calculations, which could account for the low diffusion coefficient of aniline from the result of molecular dynamics (MD) simulations. In addition, PBAT membranes displayed excellent stability in pervaporation experiments of more than 80 h. It is anticipated that the PBAT membrane may have great potential in pervaporation recovery of valuable chemicals from dilute aqueous solutions. Highlights: Biodegradable PBAT membrane was first used to recover aniline by pervaporation.Low diffusion coefficient of aniline was further explained combining MD and DFT.The PBAT membranes exhibited excellent performance for aniline recovery. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Preparing asymmetric pervaporation membranes is a kind of promising method to enhance pervaporation membrane flux. Hydrophobic PVDF polymer can be used to prepare asymmetric pervaporation membranes, but its separation factor is relatively low. In this work, to improve the performance of PVDF membrane pervaporation, PDMS polymer was added to the PVDF membrane, and asymmetric PDMS/PVDF permeable membranes were prepared by the non‐solvent induced phase separation (NIPS) method. The effects of mass ratios of PDMS to PVDF on the membrane structures and the membrane properties were characterized by SEM, XRD, FTIR, TGA, water contact angle and mechanical strength. The results showed that the ratios of the PDMS: PVDF affect its phase‐separation behavior. As the addition of PDMS increased, the finger‐like pores on the membrane section gradually became longer, the upper surface changed from less porous to porous structure, and the lower surface structure changed from interconnected flocculent structure to porous, and the best structure of the blend membrane was achieved when the PDMS: PVDF mass ratio was 1 : 5. Therefore, the membrane had the best separation performance in separating 15 wt. % ethanol aqueous solution with a permeate total flux of 273.65 g/(m2 h) and a separation factor of 9.09 when the mass ratio of PDMS: PVDF was 1 : 5. [ABSTRACT FROM AUTHOR]

Membrane-based pervaporation (PV) for organic solvent dehydration is of great significance in the chemical and petrochemical industries. In this work, high-aluminum ZSM-5 zeolite membranes were synthesized by a fluoride-assisted secondary growth on α-alumina tubular supports using mordenite framework inverted (MFI) nanoseeds (~110 nm) and a template-free synthesis solution with a low Si/Al ratio of 10. Characterization by XRD, EDX, and SEM revealed that the prepared membrane was a pure-phase ZSM-5 zeolite membrane with a Si/Al ratio of 3.8 and a thickness of 2.8 µm. Subsequently, two categories of PV performance parameters (i.e., flux versus separation factor and permeance versus selectivity) were used to systematically examine the effects of operating conditions on the PV dehydration performance of different organic solvents (methanol, ethanol, n-propanol, and isopropanol), and their PV mechanisms were explored. Employing permeance and selectivity effectively disentangles the influence of operating conditions on PV performance, thereby elucidating the inherent contribution of membranes to separation performance. The results show that the mass transfer during PV dehydration of organic solvents was mainly dominated by the adsorption–diffusion mechanism. Furthermore, the diffusion of highly polar water and methanol molecules within membrane pores had a strong mutual slowing-down effect, resulting in significantly lower permeance than other binary systems. However, the mass transfer process for water/low-polar organic solvent (ethanol, n-propanol, and isopropanol) mixtures was mainly controlled by competitive adsorption caused by affinity differences. In addition, the high-aluminum ZSM-5 zeolite membrane exhibited superior PV dehydration performance for water/isopropanol mixtures. [ABSTRACT FROM AUTHOR]

We present a hybrid-view-based knowledge distillation framework, termed HVDistill, to guide the feature learning of a point cloud neural network with a pre-trained image network in an unsupervised manner. By exploiting the geometric relationship between RGB cameras and LiDAR sensors, the correspondence between the two modalities based on both image-plane view and bird-eye view can be established, which facilitates representation learning. Specifically, the image-plane correspondences can be simply obtained by projecting the point clouds, while the bird-eye-view correspondences can be achieved by lifting pixels to the 3D space with the predicted depths under the supervision of projected point clouds. The image teacher networks provide rich semantics from the image-plane view and meanwhile acquire geometric information from the bird-eye view. Indeed, image features from the two views naturally complement each other and together can ameliorate the learned feature representation of the point cloud student networks. Moreover, with a self-supervised pre-trained 2D network, HVDistill requires neither 2D nor 3D annotations. We pre-train our model on nuScenes dataset and transfer it to several downstream tasks on nuScenes, SemanticKITTI, and KITTI datasets for evaluation. Extensive experimental results show that our method achieves consistent improvements over the baseline trained from scratch and significantly outperforms the existing schemes. The source code is available at https://github.com/zhangsha1024/HVDistill. [ABSTRACT FROM AUTHOR]

Principal Component Analysis (PCA) serves as a valuable tool for analyzing membrane processes, offering insights into complex datasets, identifying crucial factors influencing membrane performance, aiding in design and optimization, and facilitating monitoring and fault diagnosis. In this study, PCA is applied to understand operational features affecting pervaporation desalination performance of PVA-based TFC membranes. PCA-biplot representation reveals that the first two principal components (PCs) accounted for 62.34% of the total variance, with normalized permeation with selective layer thickness (Pnorm), water permeation flux (P), and operational temperature (T) contributing significantly to PC1, while salt rejection dominates PC2. Membrane clustering indicates distinct influences, with membranes grouped based on correlation with operational factors. Excluding outliers increases total variance to 74.15%, showing altered membrane arrangements. Interestingly, the adopted strategy showed a high discrepancy between P and Pnorm, indicating the relevance of comparing between PVA membranes with specific layers and those with none. PCA results showed that Pnorm is more important than P in operational features, highlighting its significance in both research and practical applications. Our findings show that even know P remains a key performance property; Pnorm is critical for developing high-performance, efficient, and economically viable pervaporation desalination membranes. Subsequent PCA for membranes without specific layers (M1 to M6) and with specific layers (M7 to M11) highlights higher total variance and influence of variables, aiding in understanding membranes' behavior and suitability under different conditions. Overall, PCA effectively delineates performance characteristics and potential applications of PVA-based TFC membranes. This study would confirm the applicability of the PCA approach in monitoring the operational efficiency of pervaporation desalination via these membranes. [ABSTRACT FROM AUTHOR]

Today, chemistry and nanotechnology cover molecular separations in liquid and gas states by aiding in the design of new nano-sized materials. In this regard, the synthesis and application of two-dimensional (2D) nanomaterials are current fields of research in which structurally defined 2D materials are being used in membrane separation either in self-standing membranes or composites with polymer phases. For instance, pervaporation (PV), as a highly selective technology for liquid separation, benefits from using 2D materials to selectively transport water or other solvent molecules. Therefore, this review paper offers an interesting update in revising the ongoing progress of PV membranes using 2D materials in several applications, including solvent purification (the removal of water from organic systems), organics removal (the removal of organic molecules diluted in water systems), and desalination (selective water transport from seawater). In general, recent reports from the past 3 years have been discussed and analyzed. Attention has been devoted to the proposed strategies and fabrication of membranes for the inclusion of 2D materials into polymer phases. Finally, the future trends and current research gaps are declared for the scientists in the field. [ABSTRACT FROM AUTHOR]

Blended cellulose/chitin membranes with various mixing ratios were successfully prepared by a co-solvent method from cellulose carbamate (CC) and chitin (CT) in an alkali/urea aqueous system. The blended solutions were characterized by rheological measurements. Blending CT with CC effectively enhanced the thermal stability of the as-obtained CT solution. The prepared membranes were characterized by FTIR, 13C NMR, XRD, TG, XPS, SEM, AFM, Raman, and tensile tests. CC and CT were homogeneously distributed in the blended membranes which clearly demonstrates the compatibility between the two polymers. The blended membrane with 20 wt% CT exhibited outstanding thermal stability and mechanical properties. Furthermore, all membranes were subjected to pervaporation tests. The blended membranes demonstrated excellent separation performance in pervaporation of water (6 wt%)-butanol (94 wt%) mixtures. Among all the membranes, the blended membrane with 20 wt% CT loading demonstrated the best pervaporation performance, achieving a permeation flux of 414.4 ± 40.1 g m−3 h−1 and a separation factor of 798.9 ± 10.5. In addition, the membranes showed stable separation performance over 3 days of continuous pervaporation. Therefore, this study provides guidance and reference for the design of high-efficiency pervaporation polymer blended membranes. [ABSTRACT FROM AUTHOR]

In this study, Principal Component Analysis (PCA) was applied to discern the underlying trends for 31 distinct MFI (Mobil No. 5)-zeolite membranes of 11 textural, chemical, and operational factors related to manufacturing processes. Initially, a comprehensive PCA approach was employed for the entire dataset, revealing a moderate influence of the first two principal components (PCs), which collectively accounted for around 38% of the variance. Membrane samples exhibited close proximity, which prevented the formation of any clusters. To address this limitation, a subset acquisition strategy was followed, based on the findings of the PCA for the entire dataset. This resulted in an enhanced overall contribution and the revelation of diverse patterns among the membranes and the considered manufacturing factors (total variance between 55% and 77%). The segmentation of the data unveiled a robust correlation between silica (SiO2) concentration and pervaporation conditions. Additionally, a notable clustering of the chemical compositions of the preparation solutions underscored their significant influence on the operational efficacy of MFI zeolite membranes. On the other hand, an exclusive chemical composition of the preparation solution was noticed. This highlighted the high influence of the chemical composition on the operational efficiency of MFI zeolite membranes. The coupling of PCA with experimental results can provide a data-driven enhancement strategy for the manufacturing of MFI-type zeolite membranes used for ethanol/water separation. [ABSTRACT FROM AUTHOR]

Abstract Membrane osmotic distillation (OD) is applied in this work for the partial dealcoholization of beer (5.2 v/v% alcohol content) to diminish its ethanol content by around 50% giving rise to a low alcohol beer. A compromise is sought between the low alcoholic degree achieved and beer sensory properties. Moreover, the feasibility of the membrane OD process intensification is studied thanks to its combination with membrane pervaporation (PV). Two successive PV stages, one hydrophobic and the other hydrophilic, allow the production of recycled water (with less than 0.5 wt% ethanol) for the membrane OD operation and bioethanol (99% ethanol) as valuable byproduct.

Among the family of two-dimensional materials, the emerging MXenes materials have gained widespread popularity due to the unique properties such as ultra-thin structure, good electrical conductivity, tunable surface functionality, and excellent photothermal conversion. Improvement of a range of desalination materials with MXenes has led to the widespread application in the field of desalination. The aim of this paper is to review the recent developments in a range of desalination strategies using MXenes, and to discuss in detail the application and development of MXenes materials in the fields of capacitive deionization, solar interfacial evaporation, and pervaporation desalination. The excellent desalination capabilities of MXenes could provide a solution to the current growing freshwater crisis.

The present study harnessed a commercially available polydimethylsiloxane (PDMSTM4060) membrane designed for the selective separation of soluble benzene (C6H6) and toluene (C7H8) compounds from an aqueous solution employing pervaporation (PV). Two distinct mathematical models, namely the universal quasi-chemical (UNIQUAC) model and the conventional driving force model, were formulated to replicate the intricate transport mechanisms of both organic solvent and water across these membranes. These models were instrumental in projecting the membrane's performance across diverse operational scenarios. The anticipated results were rigorously compared with experimental data to validate the projected outcomes for non-ideal volatile organic compounds (VOCs)-water systems within the membrane. Correlations pertaining to diffusivity were derived from the model and experimental pervaporation data. Utilizing the UNIQUAC theory and derived diffusivity correlations enabled the estimation of VOCs and water permeation through the commercial membrane. Notably, for the PDMSTM4060 membrane, the established diffusivity correlations for VOCs and water were contingent upon temperature variations and the activity of VOCs. The anticipated permeation flux of VOCs and water through the membranes was prognosticated using the mass transport model in conjunction with the established diffusivity correlations. The resultant findings showcased a robust concurrence between the predictive model and the empirical data, affirming the reliability of the proposed approach.

Abstract The removal of phenolic compounds from the water was of great importance due to their high toxicity. In this study, the separation of phenol from an aqueous environment by pervaporation technique using (PVA) polyvinyl alcohol, (CA) cellulose acetate, and (PVDF) polyvinylidene fluoride membranes was tested. The effect of feed concentration up to 9000 ppm, operating temperature from 25 to 65 °C, and flow rate ranging from 2 to 6 L h−1 on the separation performance was investigated. It was found that the CA membrane possessed a higher water flux of 348.25 kg m−2 h−1 and a separation factor of 49 compared to PVDF, and PVA/SA membranes at 65 °C and a flow rate of 6 L h−1. The properties and morphology of membranes were observed using mechanical properties, contact angle, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results showed that CA has a lower contact angle of 48.3° indicating the hydrophilicity nature of the membrane, which enhances the separation process and explains the increases of water flux. Moreover, the mechanical properties test indicated that the mechanical strength of CA has a maximum tensile strength of 65.5 MPa and an % elongation of 48% compared to PVDF and PVA/SA which indicates lower roughness, manifesting its improved anti-fouling properties.

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 NEXARTM, 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 NEXARTM 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 NEXARTM PV membrane was constant at >99% for all water types. These results emphasize the robustness of PV as a process to deal with challenging saline waters.

Pervaporation is considered the most promising technology for dehydration of bioalcohols, attracting increasing attention as a renewable energy source. In this regard, the development of stable and effective membranes is required. In this study, highly efficient membranes for the enhanced pervaporation dehydration of ethanol were developed by modification of sodium alginate (SA) with a polyethylenimine (PEI) forming polyelectrolyte complex (PEC) and graphene oxide (GO). The effect of modifications with GO or/and PEI on the structure, physicochemical, and transport characteristics of dense membranes was studied. The formation of a PEC by ionic cross-linking and its interaction with GO led to changes in membrane structure, confirmed by spectroscopic and microscopic methods. The physicochemical properties of membranes were investigated by a thermogravimetric analysis, a differential scanning calorimetry, and measurements of contact angles. The theoretical consideration using computational methods showed favorable hydrogen bonding interactions between GO, PEI, and water, which caused improved membrane performance. To increase permeability, supported membranes without treatment and cross-linked were developed by the deposition of a thin dense layer from the optimal PEC/GO (2.5%) composite onto a developed porous substrate from polyacrylonitrile. The cross-linked supported membrane demonstrated more than two times increased permeation flux, higher selectivity (above 99.7 wt.% water in the permeate) and stability for separating diluted mixtures compared to the dense pristine SA membrane. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) membranes with rich functionality and a tunable pore system are promising for molecular separation. However, an inadequate pore microenvironment and low water stability may hamper the extension of their use in gas separation to liquid separation (e.g., organic solvent dehydration). In this study, we report a high‐valence Zr‐MOF membrane with high stability and tunable pore microenvironment, prepared using a mixed‐ligand strategy based on fumarate (fum) and 2‐methylfumarate (mes) ligands for the pervaporation dehydration of alcohols. The introduction of a methyl group in the ligand side chain narrowed the aperture size while balancing the hydrophilicity, thus facilitating the fast and selective permeation of water over alcohol molecules. The resulting mes/fum‐Zr‐MOF membrane with a mes content of 30% displayed excellent butanol/water separation performance with total flux of 5226 g−1·m−2·h−1, separation factor of 1281, and water content of 99.3% in the permeate, transcending the upper‐bound of state‐of‐the‐art MOF and polymer membranes, thereby exhibiting immense potential for alcohols dehydration. [ABSTRACT FROM AUTHOR]

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Synthesis and preparation of carbon membranes have been carried out and applied for desalination. Carbon is obtained from sucrose by pyrolyzing at various temperatures. Carbon membranes are made by coating alumina tubes with sucrose solution using dip-coating. The effect of carbonization temperature on the character of the membrane material and the desalination performance was investigated. This study's results indicate that the carbonization temperature modifies the characteristics of membrane material. TGA data show that solid sucrose is thermally stable up to 210°C. This result aligns with the FTIR results, which show that functional group changes occur when the carbonization temperature exceeds 200°C. The GSA data shows that the resulting adsorption isotherm is type V, indicating mesoporous material. However, the volume and pore size of the carbon membrane material is minimal. SEM results show that carbon is dense but not equitably distributed. The salt rejection reached 100%, and the water flux was greater than 10 kg.m−2.h−1 at a feed concentration of 1% and a temperature of 60°C. Salt rejection is consistent at around 100% for up to 60 h for long-term testing. The absence of significant alterations indicates the high stability of the carbon membrane. [ABSTRACT FROM AUTHOR]

Macromolecules of complex architecture find application as modifiers of commercial polymeric membrane materials. In this work, copolyimide molecular brushes (coPI) composed of polyimide backbone and poly(methacrylic acid) side chains were used to modify poly(m-phenylene iso-phthalamide) (PPA). Structure, physical, mechanical, and transport properties of dense nonporous PPA/coPI membranes containing up to 10 wt% coPI were studied. The effect of included coPI on the membrane structure was estimated using atomic force microscopy and mechanical tests. The coPI modifier contributes to the additional formation of free volume elements evenly distributed throughout the membrane. Transport properties of PPA/coPI membranes were investigated via sorption tests and pervaporation separation of methanol (MeOH) and methyl tert-butyl ether (MTBE) mixtures. The inclusion of coPI modifier in the PPA membrane leads to an increase in the total flux of the membrane. The highest separation factor was found for the PPA/coPI membrane containing 10 wt% coPI; transport properties of the best membrane were compared with the literature data on separation of the azeotropic MeOH-MTBE mixture. [ABSTRACT FROM AUTHOR]

Although carbon nanotubes possess unique characteristics to be used for separation purposes, one of the most challenging problems affecting the preparation of carbon nanotubes-incorporated-mixed matrix membranes has been ascribed to Van der Waals interactions among carbon nanotubes walls, which hinder the pristine nanotubes' ability to make good interfacial interactions within the polymer matrix. To overcome this challenge, herein, poly (styrene sulfonic acid)-grafted- multi-walled carbon nanotubes were prepared via in-situ radical polymerisation and then incorporated into poly (vinyl alcohol), resulting in enhanced pervaporation performance of poly (vinyl alcohol) membranes. The observed results indicated that poly (styrene sulfonic acid)-modified carbon nanotubes could effectively vanquish the Van der Waals forces between nanotube walls. In general, our experiments revealed that the attachment of a bulky polymer containing hydrophilic sulfonic groups could improve the pervaporation performance of a poly (vinyl alcohol) membrane. [ABSTRACT FROM AUTHOR]

Drying–wetting cycles play a crucial role in the investigation of the origin of life as processes that both concentrate and induce the supramolecular assembly and polymerization of biomolecular building blocks, such as nucleotides and amino acids. Here, we test different microfluidic devices to study the dehydration–hydration cycles of the aqueous solutions of small molecules, and to observe, by optical microscopy, the insurgence of phase transitions driven by self-assembly, exploiting water pervaporation through polydimethylsiloxane (PDMS). As a testbed, we investigate solutions of the chromonic dye Sunset Yellow (SSY), which self-assembles into face-to-face columnar aggregates and produces nematic and columnar liquid crystal (LC) phases as a function of concentration. We show that the LC temperature–concentration phase diagram of SSY can be obtained with a fair agreement with previous reports, that droplet hydration–dehydration can be reversibly controlled and automated, and that the simultaneous incubation of samples with different final water contents, corresponding to different phases, can be implemented. These methods can be further extended to study the assembly of diverse prebiotically relevant small molecules and to characterize their phase transitions. [ABSTRACT FROM AUTHOR]

The demand for the large‐scale biofuels production is very high. The use of ethanol and butanol in flex‐fuel vehicles have already been achieved, but still need improvement to decrease the gasoline‐dependence. In addition to it, the preparation of ethanol and butanol by eco‐friendly routes are still a challenge. The use of ABE route, in which acetone, butanol, and ethanol are prepared by fermentation of 5 or 6 carbon sugars, requires higher yields and better separation performance. The goal of this work was to evaluate the use of pervaporation through asymmetric activated carbon (AC) dispersed polymethylsiloxane membranes for the separation of ABE aqueous solution with 1 wt% total organics. The amount of the filler was varied from 0 to 3 wt%. Membranes were characterized by scanning electronic microscopy, Fourier transformed infrared spectroscopy, swelling in solvents, thermogravimetric analysis, and differential scanning calorimetry. Membrane with 1 wt% of AC membrane showed different behaviors both in thermal resistance, which was increased, and also in pervaporation separation index (PSI). In this condition, membrane total flux, separation factor, and PSI for ethanol were 13.2, 2.6, and 19.9 g m−2 h−1, so that sorption behavior and diffusion rates were changed. Thus, it was possible to modulate membrane properties. [ABSTRACT FROM AUTHOR]

The removal of phenolic compounds from the water was of great importance due to their high toxicity. In this study, the separation of phenol from an aqueous environment by pervaporation technique using (PVA) polyvinyl alcohol, (CA) cellulose acetate, and (PVDF) polyvinylidene fluoride membranes was tested. The effect of feed concentration up to 9000 ppm, operating temperature from 25 to 65 °C, and flow rate ranging from 2 to 6 L h−1 on the separation performance was investigated. It was found that the CA membrane possessed a higher water flux of 348.25 kg m−2 h−1 and a separation factor of 49 compared to PVDF, and PVA/SA membranes at 65 °C and a flow rate of 6 L h−1. The properties and morphology of membranes were observed using mechanical properties, contact angle, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results showed that CA has a lower contact angle of 48.3° indicating the hydrophilicity nature of the membrane, which enhances the separation process and explains the increases of water flux. Moreover, the mechanical properties test indicated that the mechanical strength of CA has a maximum tensile strength of 65.5 MPa and an % elongation of 48% compared to PVDF and PVA/SA which indicates lower roughness, manifesting its improved anti-fouling properties. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bioethanol is considered a highly promising alternative to fossil fuels due to its derivation from renewable sources. Reducing the disadvantages of conventional fermentation requires removing the product from the fermentation broth after its formation. Therefore, coupling the membrane separation with a biological process in a single unit leads a reduction of substrate and product inhibitions. RESULTS: In this work, bioethanol production was investigated in a membrane bioreactor (MBR) with sugarcane bagasse (lignocellulose waste) as a renewable source by the sulfuric acid hydrolysis process. Firstly, the optimum conditions to produce the maximum amount of sugar by acid hydrolysis were determined. Second, the membrane bioreactor and pervaporation unit equipped with poly(dimethyl siloxane) carbon nanotube/Tetrazole membrane (PDMS‐CNT/Tetrazole) was fabricated. Third, bioethanol production in a conventional batch reactor (CBR) and the novel MBR was implemented. The outcomes of the two kinds of reactors were then compared. The results illustrated that the optimum conditions for acid hydrolysis are at a temperature of 199.4 °C, an operation time of 30.77 min, and an acid concentration of 1.12%. The obtained data shows that the ethanol production in MBR was increased by 103.6% over conventional fermentation. Furthermore, the pervaporated ethanol concentration was higher than that of the broth because of the high membrane selectivity, where a maximum ethanol concentration of 165.7 g L−1 in the cold trap was achieved. CONCLUSION: Finally, the results illustrate that the MBR can decrease the cell density growth rate and dominate any substrate and product inhibitions, while keeping process productivity for ethanol quite high. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Composite membranes with a polyvinyl alcohol (PVA) selective layer composed of well-dispersed hydrophilic kaolinite particles coated on a polyvinylidene fluoride (PVDF) support were developed. They were applied to the pervaporation dehydration of the industrially important epichlorohydrin (ECH)/isopropanol (IPA)/water ternary mixture. In comparison with raw kaolinite (RK), hydrophilic kaolinite (HK) enhanced the mechanical properties, hydrophilicity, and thermal stability of the PVA selective layer, as confirmed by universal testing, the contact angle, and TGA analyses, respectively. The pervaporation results revealed that the addition of HK particles significantly enhanced the separation factor (3-fold). Only a marginal reduction in flux was observed with ECH/IPA/water, 50/30/20 (w/w %) at 40 °C. An HK particle concentration of 4 wt.% with respect to PVA delivered the highest flux performance of 0.86 kg/m2h and achieved a separation factor of 116. The PVA–kaolinite composite membrane exhibited pronounced resistance to the ECH-containing feed, demonstrating a sustained flux and separation factor throughout an extended pervaporation stability test lasting 250 h. [ABSTRACT FROM AUTHOR]

The permeability–selectivity trade‐off of membrane is a major challenge limiting the development of pervaporation (PV) technology. Rational design of high‐performance mixed matrix membranes (MMMs) has the potential to break off the trade‐off. Herein, a solvent‐assisted linker exchange‐based strategy is reported to introduce fluoroalkyl into metal–organic framework‐808 (MOF‐808). The pore size of fluorinated MOF‐808 can be adjusted with fluoroalkyl of different chain length (like trifluoromethyl and pentafluoropropyl). Then, the fluorinated MOF‐808/polyether block amide (PEBA) MMMs are prepared for the PV of n‐butanol/water. Compared with pristine PEBA membrane, 20 wt% 3F‐MOF‐808(P)/PEBA MMMs (3F = ‐CF3 group; P = postmodification method) exhibit 69% increase in permeation flux and 33% increase in separation factor in the PV of 2.5 wt% n‐butanol aqueous solutions at 70 °C. Based on Grand Canonical Monte Carlo and molecular dynamics simulations, fluorinated MOF‐808 shows better butanol affinity (pull effect) and stronger water repulsion ability (push effect). And the "push–pull effect" between fluorinated MOF‐808 with butanol/water is helpful to enhance the PV performance of MMMs. The application of "push–pull effect" provides a new strategy for the rational design of high‐performance MMMs, which is of great significance for the in‐depth research and application of PV technology. [ABSTRACT FROM AUTHOR]

The feasibility and process advantages of pervaporation process for the concentration and reduction of desulfurization wastewater were discussed ・ The results showed that the membrane permeation flux can reach 13. 8 L/(m2 ・ h), and the membrane permeation flux reaches 7.4 L/(m2 ・ h) when the water recovery rate exceeds 70% ・ The water quality of pervaporation effluent is stable, and the effluent conductivity is < 50 |mS/cm, COD < 20 mg/L・ At the same time, the inhibition effect of scale inhibitors on membrane fouling was investigated・ The use of scale inhibitors before 50% water recovery increased the average membrane permeation flux by 22・ 5%. [ABSTRACT FROM AUTHOR]

Pervaporation-based membrane technology have gained increasing interest due to their energy efficiency and environmental sustainability. Polydimethylsiloxane (PDMS) thin-film composite membranes (TFCMs) have emerged as promising candidates for alcohol permselective applications. Compared to the development of pervaporation membrane for water purification, the optimization progress with the ethanol recovery membrane has been fairly slow and fails to meet requirements of bio-alcohol production. Despite the continuous efforts on membrane materials, the role of structural, physicochemical properties for the forming progress of selective layer on substrate is not a well-attended topic. This paper summarized the design and construction considerations of PDMS composite membranes for pervaporation from the viewpoint of the transport resistance model, including the effect of selective layer, support layer, and intermediate layer, to deeply understand and precisely regulate the preparation process. We high light the key role of crosslinking and spreading of PDMS on porous support layer in membrane fabrication. The structure-activity relationship between the separation performance of transport structure with the membrane solution properties, substrate pore structure, and the fabrication methods was discussed in detail. It was indicated that the challenges for the TFCMs applied on a pilot or industrial scale include the thickness control, coating and curing time optimization, and solvent issue. Finally, it was expected for further research to optimize the membrane fabrication process, develop novel advanced membrane materials and to explore complex and potential applications the new requirements in industry.

Composite polymer membranes were obtained using the so-called dry phase inversion and were used for desalination of diluted saline water solutions by pervaporation (PV) method. The tests used a two-layer backing, porous, ultrafiltration commercial membrane (PS20), which consisted of a supporting polyester layer and an active polysulfone layer. The active layer of PV membranes was obtained in an aqueous environment, in the presence of a surfactant, by cross-linking a 5 wt.% aqueous solution of polyvinyl alcohol (PVA)—using various amounts of cross-linking substances: 50 wt.% aqueous solutions of glutaraldehyde (GA) or citric acid (CA) or a 40 wt.% aqueous solution of glyoxal. An ethylene glycol oligomer (PEG 200) was also used to prepare active layers on PV membranes. Witch its help a chemically cross-linked hydrogel with PVA and cross-linking reagents (CA or GA) was formed and used as an active layer. The manufactured PV membranes (PVA/PSf/PES) were used in the desalination of water with a salinity of 35‰, which corresponds to the average salinity of oceans. The pervaporation method was used to examine the efficiency (productivity and selectivity) of the desalination process. The PV was carried at a temperature of 60 °C and a feed flow rate of 60 dm3/h while the membrane area was 0.005 m2. The following characteristic parameters of the membranes were determined: thickness, hydrophilicity (based on contact angle measurements), density, degree of swelling and cross-linking density and compared with the analogous properties of the initial PS20 backing membrane. The physical microstructure of the cross-section of the membranes was analyzed using scanning electron microscopy (SEM) method.

This study assesses the gas and water vapor permeance of PIM-derivative thin-film composite (TFC) membranes using pervaporation and “pressure increase” methods, and provides a comparative view of “time lag” measurements of thick films obtained from our previous work. In this study, TFC membranes were prepared using PIM-1 and homopolymers that were modified with different side groups to explore their effects on gas and water vapor transport. Rigid and bulky aliphatic groups were used to increase the polymer’s free volume and were evaluated for their impact on both gas and water transport. Aromatic side groups were specifically employed to assess water affinity. The permeance of CO2, H2, CH4 and water vapor through these membranes was analyzed using the ‘pressure increase’ method to determine the modifications’ influence on transport efficiency and interaction with water molecules. Over a 20 h period, the aging and the permeance of the TFC membranes were analyzed using this method. In parallel, pervaporation experiments were conducted on samples taken independently from the same membrane roll to assess water flux, with particular attention paid to the liquid form on the feed side. The significantly higher water vapor transport rates observed in pervaporation experiments compared to those using the “pressure increase” method underline the efficiency of pervaporation. This efficiency suggests that membranes designed for pervaporation can serve as effective alternatives to conventional porous membranes used in distillation applications. Additionally, incorporating “time lag” results from a pioneering study into the comparison revealed that the trends observed in “time lag” and pervaporation results exhibited similar trends, whereas “pressure increase” data showed a different development. This discrepancy is attributed to the state of the polymer, which varies significantly depending on the operating conditions.