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The evolving membrane technology integrated with machine learning (ML) algorithms can significantly advance the novel membrane material design and fabrication. Although several studies have reported ML-based assistance in membrane development, none of them have offered a complete analysis of existing ML-assisted membrane fabrication methods from material design perspective. A two-way information gateway is therefore necessary to achieve the desired objective, whereby experienced researchers and data scientists from both sides need to provide valuable insights into novel membrane development process. In this work, we offer a midway platform by providing an overall view and scopes of ML uses in membrane science. This is accomplished by analyzing reported ML-assisted membrane fabrications via lensing through the overall ML development. This work culminates in identifying four crucial factors affecting ML-assisted membrane development: data mining, material functional description, selection of ML models and model interpretation. A future direction is proposed by making specific ML models and descriptors suggestions, in addition to molecular similarity analysis technique and ML-based image processing. We believe the proposed approaches and analyses through our identified lens will prove crucial for the future of ML-assisted membrane material design and development. [ABSTRACT FROM AUTHOR]

Alkaline zinc-iron flow battery (AZIFB) is promising for stationary energy storage to achieve the extensive application of renewable energies due to its features of high safety, high power density and low cost. However, the major bottlenecks such as the occurrence of short circuit, water migration and low efficiency have limited its further applications, of which an ion-conducting membrane acts as a pivotal role in addressing these issues. The benchmark Nafion series membranes or anion-exchange membranes are confronted with their low ionic conductivity or poor stability in alkaline media. Therefore, a membrane is required to possess (1) excellent stability to avert the occurrence of short circuit resulted from the destruction of zinc dendrite and degradation of membrane caused by alkaline media, (2) low area resistance and high selectivity to achieve a high efficiency in time of the charge-discharge procedure of AZIFB. In this review, we will start from a brief introduction of AZIFB and cover the categories of membranes applied in AZIFB. And then the fundamental aspects of the membrane, including ion transport mechanism, fabrication & structure design and performance optimization will be highlighted. Finally, the challenges and prospects of the membranes for AZIFB applications will be briefly proposed and discussed. [ABSTRACT FROM AUTHOR]

Membrane technology is one of reliable options for treatment of oil/water emulsion. It is highly attractive because of its effectiveness in separating fine oil droplets of 2 h bar) for PSF/PEG-0 membrane in comparison to the most optimum one of PSF/PEG-60. It corresponded to an energy saving of up to ~66%. The pumping energy could further be reduced from 27.0 to 7.6 Wh/m3 by operation under ultra-low pressure from 0.2 to 0.05 bar. Sustainable permeability could be achieved when treating 1000 ppm oil/water emulsion, but severe membrane fouling was observed when treating emulsion containing crude oils of >3000 ppm to a point of no flux.

Within the framework of the MABMEM research project, new high‐performance membranes are being developed for sustainable water management. The performance of the membranes will be evaluated in comparative and standardized fouling tests as well as in terms of the removal of trace impurities on a laboratory scale. Seven candidates are currently being tested in demonstrator trials with real‐water matrix in a waterworks for the direct treatment of dam water without prior coagulation over a period of 6 months. Subsequently, the new membrane materials will be operated with the effluent of a wastewater treatment plant. [ABSTRACT FROM AUTHOR]

This review provides a comprehensive overview on the quickly developing field of polymeric hollow fiber (HF) nanofiltration (NF), including membrane (module) and process design, operational parameters, and full-scale applications. Six different methods are currently used to produce HF NF membranes: phase inversion, interfacial polymerization, grafting, coating, polyelectrolyte multilayers (PEM) and chemistry in a spinneret. While all methods have their strengths and weaknesses, several PEM based membranes stand out because of their high chemical stability. This combination of geometry and chemical stability can make HF NF a sustainable alternative to spiral wound NF. This is especially the case for applications with a high fouling load where, in contrast to spiral wound NF, HF NF typically does not require an intensive pre-treatment. In academic settings, experiments are typically done in small modules with single-component feeds. Several studies showed that it is important, but not always straightforward, to correlate these lab scale results to full scale performance. Indeed, process design parameters such as crossflow velocity and staging partly determine energy consumption and retention and need to be taken into account. Partly based on these insights and developments, in the last five years commercial HF NF modules have rapidly become available. At least 59 pilot-scale and 26 full-scale HF NF plants are currently in operation or under construction, mostly focusing on water treatment. A comparison between these plants shows that HF NF can be applied for a broad range of applications with excellent scalability, highlighting the growth potential for HF NF in the coming years. [Display omitted] • Hollow fiber nanofiltration (HF NF) has become a mature technology. • HF NF is especially competitive for feed streams with high fouling loads. • Chemical and mechanical stability of HF NF membranes are paramount for commercial success. • HF NF is applied on full-scale worldwide. [ABSTRACT FROM AUTHOR]

Pervaporation is a vapor pressure-driven membrane desalination process that can desalinate water with greater total dissolved solids than conventional reverse osmosis. This review analyzes the performance (flux and permeance) of membrane materials used for pervaporation desalination. Poly(vinyl alcohol) (PVA), silica/silicate, graphene oxide (GO), and zeolite were the most frequently used materials to synthesize pervaporation desalination membranes. PVA is the most common material and it yields a relatively high permeance. Surface free energies of different materials were evaluated as well, to analyze the scaling/fouling propensity of the current common pervaporation desalination membranes. PVA is found to be more likely to experience scaling by gypsum while adding organic silica/silicate or GO has the potential to mitigate this issue. When comparing PVA and polyvinylidene fluoride, the hydrophobic polymer is more likely to experience scaling/fouling than hydrophilic polymers. These results indicate that future development in membranes for high-efficiency pervaporation desalination may benefit from emphasizing materials with higher hydrophilicity. • Pervaporation is a promising process for the desalination of high salinity waters. • Composite membranes can achieve high water permeance in pervaporation desalination. • PVA is the main polymer used to make high flux pervaporation membranes. • Integration of organic silica or graphene oxide to PVA can help mitigate scaling. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a separation process based on the vapor transport across the hydrophobic microporous membrane driven by the vapor pressure gradient across the membrane. This process can be used for various applications such as seawater desalination, wastewater treatment, separation of volatile compounds, concentration of non-volatile compounds and processing of dairy fluids. Comparing with other separation processes, the MD process possesses unique characteristics such as 100% (theoretical) rejection, mild operation conditions, insensitive to feed concentration and stable performance at high contaminant concentrations. Due to high oil prices in recent years, extensive research has been devoted to MD in the areas of membrane materials, module configurations, process applications and hybrid systems. This review aims to summarize the recent advances in MD and provide perspectives for its future R&D. [ABSTRACT FROM AUTHOR]

The use of electrically conducting polymers for membrane development is an interesting research area of membrane science and technology. Electrically conducting polymers have been identified as a promising class of materials for membrane development owing to their unique electroactive properties, reversible redox behavior, and the potential for ease of processing. In the present review, an attempt has been made to describe the advances in the use of electrically conducting polymers to membrane development and to understand their salient features and how these features can be optimized to exhibit advanced or novel functions in membrane development. This article also presents significant literature detailing the scientific interest in electrically conducting polymers for membrane development. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E189-E197, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21262 [ABSTRACT FROM AUTHOR]

Abstract: High-throughput (HT) technology has proven to be a powerful tool to rapidly and efficiently screen materials and processes. The objective of this study was to investigate the applicability of HT technology for membrane bioreactors (MBRs). For this purpose, a prototype HT-MBR consisting of six parallel filtration membrane modules was developed. The performance of the system was validated by studying its reproducibility, scalability and reliability in terms of critical flux (CF) and filtration index (FI). The tests were performed using both lab-made polysulfone membranes (PSFL) and commercial (Toray) polyvinylidene fluoride (PVDFT) membranes. The system could be used to measure the CF simultaneously in parallel operation for six different membranes. The percentage standard deviations (%σ) on the FIs were respectively 2–7%, 3–23% and 7–16% for repeated filtrations, filtrations in different module positions (interchanged positions) and filtrations with different module areas. Improved reproducibility was obtained for tests using the commercial PVDFT membrane with a %σ of 5–7% and 4–7% for repeated filtrations on single position and interchanged positions, respectively, as ascribed to more homogeneous membrane properties over different samples. The overall results prove that the developed HT-MBR can be used as an efficient tool for fouling studies, for testing and developing membranes for MBR application and for studying the overall MBR process. Also, using six replicate membrane modules allows for a level of statistical analysis that normally cannot be performed on conventional MBR testing systems due to time, energy, cost and technical limitations. [Copyright &y& Elsevier]

Radiation-induced grafted ion exchange membranes based on functionalized polystyrene were tested for the first time in reverse electrodialysis (RED). Сation and anion exchange membranes based on sulfonated and quaternized/chloromethylated poly(styrene- co -divinylbenzene) grafted on UV-oxidized polymethylpentene films with different conductivity and selectivity relationships were compared with each other and with different commercial ion-exchange membranes (IEMs), FujiFim® Type 1 and Type 2 and RALEX®. The synthesized grafted membranes provided the highest power density of lab-scale stacks with a total active membrane area of 72 cm2 with the use of 0.1 М/1 М NaCl (0.67 W m−2) and 0.1 М/5 М NaCl (2.1 W m−2) solutions. The use of grafted membranes with a low resistance ~0.5 Ω cm2 (0.5 М NaCl, 25 °C) did not benefit the stack resistance; the low selectivity of such membranes resulted in a lower voltage and a high non-selective diffusion current of the RED stack. Higher power densities and current efficiencies in some model systems are observed for stacks with grafted membranes with lower conductivity and higher selectivity. • Radiation-induced grafted membranes were firstly tested in reverse electrodialysis (RED). • RED stacks with grafted membranes were compared with FujiFim® T1, T2 and RALEX® membranes. • Stacks with grafted membrane show the highest performance. • Maximal net power densities are 0.67 and 2.1 W m−2 with 0.1/1М NaCl and 0.1/5М NaCl. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to investigate the feasibility of high throughput (HT) screening techniques for pressure-driven membrane processes. For this purpose, a HT-filtration module, allowing to perform 16 pressure-driven separations simultaneously, was designed. The potential of the developed equipment and of the HT-screening concept in general was validated by demonstrating both the reproducibility of experimental flux and selectivity data, and the scalability of these data between the HT-module and a conventional dead-end filtration set-up. Data were obtained with two solvent resistant nanofiltration (SRNF) membranes: a laboratory-prepared polyimide (PI) and a commercial MPF-50 membrane. The reproducibility of the data was highly encouraging, proving that this HT-approach can be a useful tool to rapidly screen a large array of operational parameters in membrane processes and of synthesis parameters in the development of new membranes. [Copyright &y& Elsevier]

Abstract: The development of functional photosynthetic units in Rhodobacter sphaeroides was followed by near infra-red fast repetition rate (IRFRR) fluorescence measurements that were correlated to absorption spectroscopy, electron microscopy and pigment analyses. To induce the formation of intracytoplasmic membranes (ICM) (greening), cells grown aerobically both in batch culture and in a carbon-limited chemostat were transferred to semiaerobic conditions. In both aerobic cultures, a low level of photosynthetic complexes was observed, which were composed of the reaction center and the LH1 core antenna. Interestingly, in the batch cultures the reaction centers were essentially inactive in forward electron transfer and exhibited low photochemical yields FV/FM, whereas the chemostat culture displayed functional reaction centers with a rather rapid (1–2 ms) electron transfer turnover, as well as a high FV/FM of ∼0.8. In both cases, the transfer to semiaerobiosis resulted in rapid induction of bacteriochlorophyll a synthesis that was reflected by both an increase in the number of LH1–reaction center and peripheral LH2 antenna complexes. These studies establish that photosynthetic units are assembled in a sequential manner, where the appearance of the LH1–reaction center cores is followed by the activation of functional electron transfer, and finally by the accumulation of the LH2 complexes. [Copyright &y& Elsevier]

In this study, oleic acid was used to functionalize carbon nanotubes (CNTs), successfully. Then, a novel composite membrane was fabricated by coating of polyvinylidene fluoride (PVDF) solution containing oleic acid-functionalized CNTs on polytetrafluoroethylene (PTFE) support membrane for use in vacuum membrane distillation (VMD) process. The coating process was performed using vacuum filtration method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic force microscopy (AFM) analysis and water contact angle (WCA) measurement were used to characterize the functionalized CNTs and the fabricated membranes. Effects of the functionalized CNTs loading on membrane performance were investigated. It was found that compared to the PTFE/carboxylated CNTs composite membrane, the PTFE/oleic acid-functionalized CNTs composite membrane with WCA of about 133.2° shows better performance (higher permeation flux and salt rejection), in lower CNTs loading. Taguchi method was applied to design a minimum number of experiments to investigate the effects of some operating parameters including feed temperature, feed concentration and feed flow rate on the membrane performance. The optimum conditions were obtained as: temperature of 70 °C, concentration of 10,000 ppm and flow rate of 150 LPH. This work demonstrated that the fabricated PTFE/oleic acid-functionalized CNTs composite membrane is a suitable candidate to achieve high water flux (89 LMH) and salt rejection (99.45% which is 30% higher than unmodified PTFE membrane) in the VMD process. Unlabelled Image • Oleic acid was used to functionalize carbon nanotubes (CNTs), successfully. • A novel PTFE/oleic acid-functionalized CNTs composite membrane was fabricated. • Desalination was performed via vacuum membrane distillation (VMD) process. • Taguchi method was applied to investigate the effects of operating parameters. • High water flux (111.25 LMH/bar) and salt rejection (99.45%) were achieved. [ABSTRACT FROM AUTHOR]

Membrane technology is one of reliable options for treatment of oil/water emulsion. It is highly attractive because of its effectiveness in separating fine oil droplets of <2 µm sizes, which is highly challenging for other processes. However, the progress for its widespread implementations is still highly restricted by membrane fouling. Most of the earlier studies have demonstrated the promise of achieving more sustained filtration via membrane material developments. This study addresses issues beyond membrane development by assessing the impact of membrane material (blend of polysulfone, PSF and polyethylene glycol, PEG), operational pressure, and crude oil concentration on the filtration performance of oil/water emulsion. The filtration data were then used to project the pumping energy for a full-scale system. Results show that fouling resistant membrane offered high oil/water emulsion permeability, which translated into a low energy consumption. The oil/water emulsion permeability was improved by three-fold from 45 ± 0 to 139 ± 1 L/(m2 h bar) for PSF/PEG-0 membrane in comparison to the most optimum one of PSF/PEG-60. It corresponded to an energy saving of up to ~66%. The pumping energy could further be reduced from 27.0 to 7.6 Wh/m3 by operation under ultra-low pressure from 0.2 to 0.05 bar. Sustainable permeability could be achieved when treating 1000 ppm oil/water emulsion, but severe membrane fouling was observed when treating emulsion containing crude oils of >3000 ppm to a point of no flux. [ABSTRACT FROM AUTHOR]

A role for the peripheral (B800-850) light-harvesting complex in vesicularization of the Rhodobacter sphaeroides intracytoplasmic membrane (ICM), suggested from studies in mutant strains lacking one or more of the pigment-protein complexes, was examined further in the wild-type strain NCIB 8253 grown at high (∼1000 W m), moderate (∼300 W m), and low (∼100 W m) light intensities. The resulting ICM vesicles (chromatophores) had B800-850 levels related inversely to irradiance and banded in rate-zone sedimentation at ∼1.10, 1.09, and 1.07 g ml, respectively. Equilibrium centrifugation on iso-osmotic gradients indicated that this distinct sedimentation behavior resulted solely from differences in hydrodynamic radii. These size differences were confirmed by gel-exclusion chromatography and in electron micrographs of thin-sectioned cells. A pulse-chase study of ICM growth following a tenfold reduction in light intensity showed a relatively slow equilibration of membrane proteins during adaptation, and that new protein was incorporated largely into additional ICM formed at the lowered illumination level, giving rise to chromatophores of reduced size and elevated B800-850 content. These results provide further evidence for a model in which the B800-850 complex both drives development of vesicular ICM in Rba. sphaeroides and determines the size of resulting vesicles. [ABSTRACT FROM AUTHOR]

• PEI-crosslinked PVDF membranes showed pH-responsive charge-switchable property. • Patterned membranes enhanced the biofilm formation. • pH = 7 was the optimal pH for biofilm formation on PEI-crosslinked PVDF membrane. • pH above 9 was best for microalgal harvesting on PEI-crosslinked membrane. • PEI-crosslinked PVDF membrane showed a positively charged surface below pH 8. Harvesting efficiency is one of the key issues restricting the further commercialization of microalgae. Traditional biofilm studies only tend to focus on enhancing biofilm formation, while neglecting the subsequent harvesting of the biofilm. In this study, a win–win strategy for high-density microalgal cultivation and low-cost harvesting through biofilm cultivation on a pH-responsive, charge-switchable, patterned membrane was investigated using a polyethylenimine (PEI)-crosslinked polyvinylidene fluoride (PVDF) membrane. The patterned membranes were prepared by spray-modified non-solvent induced phase inversion, and the effect of pattern height on biofilm formation and microalgal harvesting was investigated. The PEI-crosslinked PVDF membrane surface was positively charged below pH 8 and negatively charged above pH 9, resulting in a higher attractive energy below pH 8 and a repulsive energy above pH 9 according to the extended Derjaguin, Landau, Verwey, Overbeek model. Patterning of these membranes increased the active area for microalgal attachment, and created a low-shear area in the valleys that prevents early detachment of microalgal cells. Membranes with a higher pattern height resulted in faster biofilm development and increased final biomass accumulation. Low-energy membrane vibration was applied to enhance cell detachment. pH = 7 was found to be the optimal pH for enhanced microalgal biofilm formation on PEI-crosslinked patterned membranes, and a switch to pH = 10 was best for microalgal harvesting. [ABSTRACT FROM AUTHOR]

Forward osmosis is an emerging osmosis-driven membrane process, which has benefits of low energy consumption, low operational pressure, easy equipment, and low fouling. This review paper summarized the recent advances of forward osmosis technology based on the publications collected from Science Direct since 1996. Through the statistical analysis of 9345 articles, it was concluded that the research of forward osmosis mainly focused on the draw solution, membrane development, membrane fouling, and energy consumption. In this review, the most significant influencing factors of forward osmosis technology were analyzed, including membrane development, draw solution, and the operating conditions; then the existing problems were discussed in detail, including concentration polarization, membrane fouling, and reverse solute diffusion, which are closely related to each other; finally, the innovations and bottlenecks of forward osmosis technology were summarized, and the future perspectives were discussed. More attention should be paid to developing new membrane materials, designing effective draw solutions, minimizing the energy consumption, and creating energy-efficient recovery processes, to expand its commercial application. This review will deepen the understanding to forward osmosis technology, and provide comprehensive information for the scientific researcher and application engineers to facilitate the research and development of forward osmosis technology. Image 1 • The recent advances of FO process in water treatment were analyzed and summarized. • The influencing factors, membrane, draw solution, operating condition were discussed. • The main regeneration methods of draw solution were introduced and compared. • The future direction of forward osmosis technology development was discussed. [ABSTRACT FROM AUTHOR]

• Membrane charge and patterning significantly improve the membrane performance. • Critical pressures of all sPSf blend patterned membranes were higher than 2.5 bar. • Membrane with wave patterns showed the highest CWP and membrane flux. • sPSf blend patterned membranes showed the lowest interaction energy. • A higher velocity and wall shear were found on the pattern apexes. Membranes have a lot of potential for harvesting microalgae, but membrane fouling is hampering their breakthrough. In this study, the effects of charge and corrugated surface on membrane filtration performance were investigated. The clean water permeance (CWP), the microalgae harvesting efficiency and the membrane flux for a microalgal broth were determined using patterned polysulfone (PSf) membranes with different shapes of the surface patterns and containing different charge densities by blending sulfonated polysulfone (sPSf). The flow behavior near the patterned membrane surface, as well as the interaction energy between membrane and microalgae were investigated using computational fluid dynamics (CFD) simulation and the improved extended "Derjaguin, Landau, Verwey, Overbeek" (XDLVO) theory, respectively. Membrane charge and pattern shape significantly improve the membrane performance. The critical pressures of all sPSf blend patterned membranes were higher than 2.5 bar. A 4.5w% sPSf blend patterned membranes with wave patterns showed the highest CWP (2300 L/m2 h bar) and membrane flux in the microalgal broth (1000 L/m2 h bar) with 100% harvesting efficiency. XDLVO analysis showed that sPSf blend patterned membranes prepared obtained the lowest interaction energy and highest energy barrier for microalgal attachment. CFD simulation showed a higher velocity and wall shear on the pattern apexes. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m−2·h−1·bar−1). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane. [ABSTRACT FROM AUTHOR]