Conventional Membrane Research Articles

Synthesis of Novel Graphene Oxide-chitosan-silicon Dioxide Nanocomposite Embedded in Polysulfone Membrane for Oily Water Treatment

Oil and gas exploration activities result in generation of large quantities of produced water. Globally, for each barrel of oil, three barrels of produced water is generated. The oil content in produced water can vary between 3 and 20% depending on the location and age of the hydrocarbon well. Due to their hydrophobic nature, conventional hydrophobic polymeric membranes struggle to effectively separate oil from produced water. In this work, an innovative strategy is suggested by employing a hydrophilic/super-oleophobic nanocomposite to develop novel polymeric membranes able to effectively separate oil content from produced water without negatively affecting the other membrane properties such as the total flux and fouling. Graphene oxide-chitosan-silicone oxide (GO-CH-SiO2) nanocomposite was synthesized by functionalizing graphene oxide (GO) with chitosan (CH) and silicon dioxide (SiO2). To improve the membrane flux, anti-fouling propensity, and oil rejection, the synthesized nanocomposites were doped in the polysulfone membranes matrix. The effect of GO-CH-SiO2 concentration, GO:CH ratio, and GO-CH:SiO2 ratio on the performances of developed membranes was experimentally assessed, and morphology of the synthesized membrane was investigated using appropriate characterization techniques. The experimental results showed that the membrane with GO:CH of 1:2 and GO-CH: SiO2 ratio of 1:6.5 showed the highest pure water permeation flux of 28.35 LMH/bar with a comparable flux recovery rate of 76% and oil rejection efficiency of 98.5%. The study’s findings underscore the potential of GO-CH-SiO2 nanocomposite membranes for oil–water separation research, presenting a promising solution for treating produced water in the oil and gas industry. Further research is needed to scale up this technology and improve membrane performance by optimizing the nanocomposite composition and conducting long-term performance tests.

Enhancing sustainability and power generation from sewage‐driven air‐cathode microbial fuel cells through innovative anti‐biofouling spacer and biomass‐derived anode

AbstractBackgroundRecently, the concept of the membrane‐less microbial fuel cell (MFC) has gained traction to avoid the high internal resistance that is created upon utilizing conventional membranes. Nevertheless, an overlooked problem arises from the ingress of oxygen from the cathode side into the anolyte solution, fostering the formation of biofilms by aerobic microorganisms on the cathode surface. This biofilm layer poses a formidable impediment, leading to cell disconnection. Moreover, low surface area of conventional anodes is another important issue behind the low power density generation. In this research, a novel approach to circumvent biofilm formation and achieve stable and high‐power‐density output from MFCs by harnessing a commercial antibacterial spacer is introduced.ResultsAir‐cathode, sewage‐driven MFCs showed continuous power generation without the need for external microorganisms. Conversely, the absence of the innovative membrane resulted in a catastrophic power breakdown after 125 h of operation due to the formation of a dense biofilm layer on the cathode. Through the utilization of the proposed membrane strategy, stable power density output of 100 ± 8, 135 ± 11 and 142 ± 10 mW m−2 with carbon cloth, carbon paper and carbon felt anodes, respectively, was achieved. Moreover, a novel anode is introduced from graphitization of grape tree branches. The proposed anode could increase the generated power to 516 ± 17 mW m−2 from the sewage‐driven air‐cathode MFC, more than three times compared to the best conventional anode, carbon felt.ConclusionThis study provides significant solutions for sustainability, low‐performance and high‐cost problems of microbial fuel cells. © 2024 Society of Chemical Industry (SCI).

Hydrophobic Modification of Cellulose Acetate and Its Application in the Field of Water Treatment: A Review

With the inherent demand for hydrophobic materials in processes such as membrane distillation and unidirectional moisture conduction, the preparation and application development of profiles such as modified cellulose acetate membranes that have both hydrophobic functions and biological properties have become a research hotspot. Compared with the petrochemical polymer materials used in conventional hydrophobic membrane preparation, cellulose acetate, as the most important cellulose derivative, exhibits many advantages, such as a high natural abundance, good film forming, and easy modification and biodegradability, and it is a promising polymer raw material for environmental purification. This paper focuses on the research progress of the hydrophobic cellulose acetate preparation process and its current application in the water-treatment and resource-utilization fields. It provides a detailed introduction and comparison of the technical characteristics, existing problems, and development trends of micro- and nanostructure and chemical functional surface construction in the hydrophobic modification of cellulose acetate. Further review was conducted and elaborated on the applications of hydrophobic cellulose acetate membranes and other profiles in oil–water separation, brine desalination, water-repellent protective materials, and other separation/filtration fields. Based on the analysis of the technological and performance advantages of profile products such as hydrophobic cellulose acetate membranes, it is noted that key issues need to be addressed and urgently resolved for the further development of hydrophobic cellulose acetate membranes. This will provide a reference basis for the expansion and application of high-performance cellulose acetate membrane products in the environmental field.

Graphene Oxide and its Composites: Advanced Membranes for Selective Water Permeation.

Graphene oxide (GO) membranes have gained significant attention as a promising material for separation by selective permeation processes due to their advantageous structural and chemical properties, including high water permeability, chemical resistance, and mechanical strength. In this study, we explore the potential applications of GO membranes in pervaporation to separate liquid mixtures. The layered structure and hydrophilic nature of GO membrane facilitate rapid and selective water transport through angstrom-scale interlayer spacings, resulting in superior performance over conventional polymeric and inorganic membranes. The unique mass transport mechanisms - slip flow and molecular alignment - enable GO membranes to selectively permeate water over organic solvents. For chemical dehydration, GO membranes are the most potential candidates. Furthermore, advancements in composite GO membranes and cross-linking techniques that improve their stability and separation performance are discussed. This study highlights the advantages of GO membranes and their potential to replace or complement existing technologies, by emphasizing their role in advancing membrane-based separation and promoting environmental sustainability. Future research is expected to optimize the fabrication techniques for GO membranes and expand their application scope.

Material Aspects of Thin-Film Composite Membranes for CO2/N2 Separation: Metal–Organic Frameworks vs. Graphene Oxides vs. Ionic Liquids

Thin-film composite (TFC) membranes containing various fillers and additives present an effective alternative to conventional dense polymer membranes, which often suffer from low permeance (flux) and the permeability–selectivity tradeoff. Alongside the development and utilization of numerous new polymers over the past few decades, diverse additives such as metal–organic frameworks (MOFs), graphene oxides (GOs), and ionic liquids (ILs) have been integrated into the polymer matrix to enhance performance. However, achieving desirable interfacial compatibility between these additives and the host polymer matrix, particularly in TFC structures, remains a significant challenge. This review discusses recent advancements in TFC membranes for CO2/N2 separation, focusing on material structure, polymer–additive interaction, interface and separation properties. Specifically, we examine membranes operating under dry conditions to clearly assess the impact of additives on membrane properties and performance. Additionally, we provide a perspective on future research directions for designing high-performance membrane materials.

Enhancing differentiation and functionality of insulin-producing cells derived from iPSCs using esterified collagen hydrogel for cell therapy in diabetes mellitus

BackgroundIslet transplantation is a recommended treatment for type 1 diabetes but is limited by donor organ shortage. This study introduces an innovative approach for improving the differentiation and functionality of insulin-producing cells (IPCs) from iPSCs using 3D spheroid formation and hydrogel matrix as an alternative pancreatic islet source. The extracellular matrix (ECM) is crucial for pancreatic islet functionality, but finding the ideal matrix for β-cell differentiation has been challenging. We aimed to advance IPC differentiation and maturation through an esterified collagen hydrogel, comparing its effectiveness with conventional basement membrane extract (BME) hydrogels.MethodsiPSCs were differentiated into IPCs using a small molecule-based sequential protocol, followed by spheroid formation in concave microwells. Rheological analysis, scanning electron microscopy, and proteomic profiling were used to characterize the chemical and physical properties of each matrix. IPCs, both in single-cell form and as spheroids, were embedded in either ionized collagen or BME hydrogels, which was followed by assessments of morphological changes, pancreatic islet-related gene expression, insulin secretion, and pathway activation using comprehensive analytical techniques.ResultsEsterified collagen hydrogels markedly improved the structural integrity, insulin expression, and cell-cell interactions in IPC spheroids, forming densely packed insulin-expressing clusters, in contrast to the dispersed cells observed in BME cultures. Collagen hydrogel significantly enhanced the mRNA expression of crucial endocrine markers and maturation factors, with IPC spheroids showing accelerated differentiation from day 5, suggesting a faster differentiation compared to single cells in hydrogel encapsulation. Insulin secretion in response to glucose in collagen environments, with a GSIS index of 2.46 ± 0.05, exceeded those in 2D and BME, demonstrating superior pancreatic islet functionality. Pathway analysis highlighted enhanced insulin secretion capabilities, evidenced by the upregulation of genes like Secretogranin III and Chromogranin A in collagen cultures. In vivo transplantation results showed that collagen hydrogel enhanced cluster integrity, tissue integration, and insulin secretion compared to non-embedded IPCs and BME groups.ConclusionEsterified collagen hydrogels demonstrated superior efficacy over 2D and BME in promoting IPC differentiation and maturation, possibly through upregulation of the expression of key secretion pathway genes. Our findings suggest that using collagen hydrogels presents a promising approach to enhance insulin secretion efficiency in differentiating pancreatic β-cells, advancing cell therapy in diabetes cell therapy.

Use of the droplet convergence effect of under-medium superlyophilic membranes in designing a system for on-demand separations of oil-in-water and water-in-oil emulsions

Separation using superwetting membranes that have discrepant interactions with water and oil, primarily those that display extreme liquid repellence, is a facile approach for oily wastewater treatment and purification of water-containing oil. However, these kinds of membranes suffer from size-sieving limitation. Owing to greater affinity toward dispersed droplets over liquid media, under-medium superlyophilic membranes have greater flexibility in the design of superwetting interfaces for oil–water separation. Herein, two membranes with completely opposite superwettabilities both in air and under oil/water media were utilized to create an integrated system for effective, on-demand separation of oil-in-water and water-in-oil emulsions. At superwetting interfaces, the under-medium superlyophilic membrane facilitates convergence of emulsion droplets while the other membrane intercepts converged droplets. As a result, the integrated membranes exhibit high purification capabilities of water and oil in surfactant-stabilized emulsions (e.g., > 99.97 % oil purification under gravity). The viscosity-dependent fluxes are > 550 L m−2h−1 when the viscosities of the liquid media are ≤ 1 mPa s. In contrast, an integrated system in which conventional in-air superhydrophilic membranes are utilized in place of the under-medium superlyophilic membranes does not efficiently separate the emulsions. The unique affinity profiles will endow under-medium superlyophilic membranes with a high potential for liquid–liquid separation.

Comparative Study of Polymer of Intrinsic Microporosity-Derivative Polymers in Pervaporation and Water Vapor Permeance Applications

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.

Exploring the effects of polyethylene and polyester microplastics on biofilm formation, membrane Fouling, and microbial communities in Modified Ludzack-Ettinger-Reciprocation membrane bioreactors

Microplastics (MPs) inevitably enter wastewater treatment plants (WWTPs), yet their impacts remain poorly understood. This study investigates the effects of MPs on system performance and membrane fouling in a Modified Ludzack-Ettinger (MLE)-Reciprocation Membrane Bioreactor (rMBR), an energy-efficient alternative to conventional membrane bioreactors. Additionally, the study examines changes in microbial community induced by different types and shapes of MPs—polyethylene (PE) pellets and polyester (PES) fibers— as well as biofilm formation on MPs, using next-generation sequencing. Results revealed that transmembrane pressure (TMP) increased 2–3 times faster in the presence of PE pellets, while TMP remained stable during the PES stage, implying that MP type and shape could influence biofouling behaviors. Furthermore, enhanced nitrate removal was observed in the aerobic tank due to denitrifying biofilm formation on MPs. However, PES MPs reduced nitrate removal efficiency from 99.6 ± 0.3 % to 90.9 ± 7.9 % and decreased the relative abundance of denitrifying bacteria. Numerous taxa showed affinity to PE pellets, including some pathogens, e.g., Norcadia and Mycobacterium. Notably, an uncultured phylum Candidatus Saccharibacteria dominated in membrane biofilm and MPs, reaching up to 37 % relative abundance. This study is the first to explore how different types and shapes of MPs affect membrane bioreactor systems, particularly with respect to microbial community structure and biofilm formation. The findings offer new insights into the influence of MPs on wastewater treatment processes and highlight the significance of the uncultured phylumCandidatus Saccharibacteriain membrane fouling.

Removal of sulfamethoxazole in an algal-bacterial membrane aerated biofilm reactor: Microbial responses and antibiotic resistance genes

Antibiotics are frequently detected in wastewater, but often are poorly removed in conventional wastewater treatment processes. Combining microalgal and nitrifying bacterial processes may provide synergistic removal of antibiotics and ammonium. In this research, we studied the removal of the antibiotic sulfamethoxazole (SMX) in two different reactors: a conventional nitrifying bacterial membrane aerated biofilm reactor (bMABR) and algal-bacterial membrane aerated biofilm reactor (abMABR) systems. We investigated the synergistic removal of antibiotics and ammonium, antioxidant activity, microbial communities, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and their potential hosts. Our findings show that the abMABR maintained a high sulfamethoxazole (SMX) removal efficiency, with a minimum of 44.6 % and a maximum of 75.8 %, despite SMX inhibition, it maintained a consistent 25.0 % ammonium removal efficiency compared to the bMABR. Through a production of extracellular polymeric substances (EPS) with increased proteins/polysaccharides (PN/PS), the abMABR possibly allowed the microalgae-bacteria consortium to protect the bacteria from SMX inactivation. The activity of antioxidant enzymes caused by SMX was reduced by 62.1–98.5 % in the abMABR compared to the bMABR. Metagenomic analysis revealed that the relative abundance of Methylophilus, Pseudoxanthomonas, and Acidovorax in the abMABR exhibited a significant positive correlation with SMX exposure and reduced nitrate concentrations and SMX removal. Sulfonamide ARGs (sul1 and sul2) appeared to be primarily responsible for defense against SMX stress, and Hyphomicrobium and Nitrosomonas were the key carriers of ARGs. This study demonstrated that the abMABR system has great potential for removing SMX and reducing the environmental risks of ARGs.

Nacre-inspired graphene oxide/polyethyleneimine-based ultra-thin heterogeneous superwetting membrane for highly stable separation of oil-in-water emulsions

Since the massive discharge of oily wastewater seriously affects both humans and natural development, the performance of conventional membrane materials in terms of interfacial stability and antifouling in the treatment of surfactant-containing emulsified oily wastewater is a major challenge. In this work, a novel nacre-inspired graphene oxide/polyethyleneimine-based ultra-thin chemically heterogeneous superwetting membrane was fabricated through vacuum-assisted self-assembly and post-modification methods for oil-in-water emulsion separation. The nacre-inspired heterogeneous membrane exhibited superhydrophilicity, underwater superoleophobicity (underwater oil contact angle was 157.7°), excellent crude oil adhesion resistance, high acid/alkaline stability, outstanding salt resistance, and good mechanical properties (Young’s modulus 1391.7 MPa). The heterogeneous membranes showed separation efficiencies of more than 99.9 % for a range of oil-in-water emulsions. The high-value membranes could achieve the permeances of 917–1256 L m−2h−1 bar−1 for pure water and 339.7–577 L m−2h−1 bar−1 for emulsion through a dead-end filter device, with the optimal long-term stable permeance only decreasing by 30.0 % compared to the initial value. After six test cycles, the membrane’s antifouling and self-cleaning properties were enhanced by constructing heterogeneous superwetting properties, and the flux recovery rate remained at 96.5 %. All of these results indicated that this method provides new ideas for the design and fabrication of highly stable and antifouling membrane materials.

Synergistic impact of Fe–Zr in novel hybrid aminoclay catalytic TFC membrane for ultrafast emerging pollutant remediation

Finding new class of materials to overcome limitation in conventional membranes is a challenging task. Use of naturally stable and sustainable alternative materials stock is an emerging task. In this direction, a novel iron-zirconium hybrid aminoclay (FZ-AC) has emerged as a promising catalyst effectively employed to alleviate fouling concerns within the framework of a biopolymer-based thin film composite (TFC), constructed on a cellulose acetate (CA) support. Notably, FZ-AC exhibits remarkable catalytic activity in the degradation of foulants through potential free radicals generated from Fe and Zr active centres in synergy with oxidising agent. The optimised catalytic membrane (FZ-TFC-1) exhibited an ultrafast degradation of congo red (CR), eriochrome black-T (EBT), crystal violet (CV), methylene blue (MB), red-brown dye (RBn), bisphenol-A (BPA), azithromycin (AZC), and Cr(VI) within 4 min. The cooperative action of redox centres of Fe and Zr metal ions synergistically accelerated the swift production of reactive species and facilitated the efficient degradation of pollutants within a notably short timeframe. Furthermore, >95% of above dyes rejection was achieved with >67 L m−2.h−1 of flux. The results of a long-term study demonstrated that FZ-TFC membranes exhibit exceptional stability, retaining their performance for a duration up to 150 h. This extended period of stability underscores the superiority of these membranes over alternative counterparts, suggesting their robustness and reliability for sustained operation in various applications. This strategic utilization of FZ-AC representing a promising avenue for enhancing the efficacy and longevity of nanofiltration membranes, thereby advancing the frontier of membrane-based separation technologies.

Supramolecular-Coordinated Nanofiltration Membranes with Quaternary-Ammonium Cyclen for Efficient Lithium Extraction from High Magnesium/Lithium Ratio Brine

Ion-selective membranes (ISM) with sub-nanosized pore channels hold significant potential for applications in saline wastewater treatment and resource recovery. Herein, novel synergistic ion channels featuring bi-periodic structures were constructed through the coordination of functional Cyclen (quaternary_1,4,7,10-tetraazacyclododecane, Q_Cyclen) and Cu2+-m-Phenylenediamine (Cu2+-MPD) to develop supramolecular membranes for lithium extraction. The exterior quaternary ammonium-rich sites exhibit a significant Donnan exclusion effect, resulting in tremendous mono/divalent (Li+/Mg2+) ion selectivity; while the interior regular-confined channels of Cyclen yield a fast vehicular pathway, facilitating water molecules and Li+ ion-selective transport. The optimized membrane exhibited an increased water permeance of 19.2 L·m-2·h-1·bar-1 and simultaneously promoted Li+/Mg2+ selectivity (achieving a selectivity of 18.5 under a Mg2+/Li+ mass ratio of 30), surpassing the trade-off limit of conventional nanofiltration membranes. Due to the acquired excellent Li+/Mg2+ selectivity, lithium extraction from simulated salt-lake brines was successfully achieved through a two-stage nanofiltration process, reducing the Mg2+/Li+ mass ratio from 40 to 1.1. This work validates the applicability of macrocyclic with intrinsic sub-nanosized channels and desired multifunctionality for developing high-performance ISM for efficient lithium separation and beyond.

Carbon-encapsulated silicon ordered nanofiber membranes as high-performance anode material for lithium-ion batteries

Silicon have attracted much attention as a promising anode material for lithium-ion batteries due to the extremely high theoretical capacity. However, its practical application is limited by the huge volume expansion during the cycling process. To address this issue, carbon-encapsulated silicon ordered nanofiber membranes were designed through a modified electrospinning technology with a strong magnetic field. Compared with the conventional nanofiber membranes, the optimized M1200 Gs anode exhibited a high discharge capacity of 1603.1 mAh·g−1 at 0.1 A·g−1, a superior rate performance, and a robust cycling stability with a reversible capacity of 658.1 mAh·g−1 at 1 A·g−1 after 100 cycles. The improved electrochemical performance was confirmed to be highly correlated with the parallel structure of nanofibers, which help to facilitate the diffusion and transport of electrons and ions, realize the stress distribution and buffer the volume changes. This work provides unique insights into designing silicon-based anodes with novel structures for lithium-ion batteries.

Nanoconfined Catalytic Membranes for EfOM Fouling Mitigation: An Intelligent “Pore-Centric” Cleaning Strategy

This study investigated the effectiveness of the nanoconfined catalytic membrane (NCCM), fabricated by nitrogen-doped carbon nanotubes (NCNT) incorporated with graphene oxide membrane (NCNT@GO-M), in mitigating fouling caused by effluent organic matter (EfOM). Compared to conventional catalytic membranes (NRCM) that lack precise spatial design and prepared with only NCNT, NCCM exhibits a unique advantage by preferentially retaining and adsorbing protein-like substances in EfOM during the fouling formation process, forming a cake layer that effectively mitigates pore blockage from irreversible foulants. Furthermore, the ordered nanoconfined structure of NCCM facilitates an intelligent “pore-centric” hierarchical degradation strategy based on the molecular size of EfOM, preferentially removing irreversible foulants caused by fulvic acid-like and low molecular weight protein-like substances. The results demonstrated effective preservation of catalytic sites by the NCCM’s advanced nanoconfined configuration and a 1.6-fold increase in the mass transfer rate of peroxymonosulfate (PMS) compared to NRCM, synergistically promoting hydroxyl radical (•OH) enrichment, resulting in rapid EfOM degradation kinetics. Additionally, chemical cleaning almost completely eliminated irreversible fouling, restoring the NCCM to near its original flux. Overall, this study sheds light on the fouling mitigation mechanisms of NCCM, aiding their tailored design and application in targeted wastewater treatment.

Sustainable control of microplastics in wastewater using the electrochemically enhanced living membrane bioreactor

Wastewater treatment plant (WWTP) discharges are major contributors to the release of microplastics (MPs) into the environment. This research work aimed to assess the performance of the novel living membrane bioreactor (LMBR), which utilizes a biological layer as a membrane filter for the removal of polyethylene (PE) MPs from wastewater. The impact of an intermittently applied low current density (0.5 mA/cm2) on the reduction of MPs in the electrochemically enhanced LMBR (e-LMBR) has also been examined. The reactors were also compared to a conventional membrane bioreactor (MBR) and an electro-MBR (e-MBR). 1H nuclear magnetic resonance spectroscopy (1H NMR) was implemented for the MPs detection and quantification in terms of mass per volume of sample.The LMBR and MBR achieved comparable mean PE MPs reduction at 95% and 96%, respectively. The MPs mass reduction in the e-LMBR slightly decreased by 2% compared to that achieved in the LMBR. This potentially indicated the partial breakdown of the MPs due to electrochemical processes. Decreasing and inconsistent NH4-N and PO4-P removal efficiencies were observed over time due to the addition of PE MPs in the MBR and LMBR. In contrast, the integration of electric field in the e-MBR and e-LMBR resulted in consistently high values of conventional contaminant removals of COD (99.72–99.77 %), NH4-N (97.96–98.67%), and PO4-P (98.44–100.00%), despite the MPs accumulation.Integrating electrochemical processes in the e-LMBR led to the development of a stable living membrane (LM) layer, as manifested in the consistently low effluent turbidity 0.49 ± 0.33 NTU. Despite the increasing MPs concentration in the mixed liquor, applying electrochemical processes reduced the fouling rates in the e-LMBR. The e-LMBR achieved comparable efficiencies in contaminant reductions as those observed in the e-MBR, while using a low-cost membrane material.

Thermal seawater desalination for irrigation purposes in a water-stressed region: Emerging value tensions in full-scale implementation

Water scarcity in arid regions has driven the spread of desalination. These systems contribute to water access but come at an intensive energy cost, and lead to brine discharge and associated environmental impacts. This work aims to investigate emerging societal issues and tensions when developing and implementing a thermal desalination system to produce irrigation water in the South of Spain. This has been done in a demonstration system for solar desalination able to recover water and salts from desalination brine. For this purpose, a context-sensitive design exercise has been implemented. First, tensions between social values expressed by diverse stakeholders have been identified. Then, a set of technical scenarios for the full-scale implementation of the system were designed and evaluated, comparing them to conventional membrane desalination. The analysis indicates high economic and energy costs to avoid the environmental impacts of increasing water production.

Application of electro-membrane bioreactor in the treatment of pharmaceutical wastewater

In the present study, the integrated process of an electro-membrane bioreactor (EMBR) with conventional membrane bioreactor (MBR) was used for wastewater treatment. The removal rates of chemical oxygen demand (COD), phosphate (PO43-), turbidity, diclofenac (DCF), and UV254 were investigated in both reactors, which operated with a sludge retention time (SRT) of 60 d and a hydraulic retention time (HRT) of 24 h. The assessment of the current density effect on DCF removal in an electrocoagulation reactor indicated that 0.5 mA/cm² was an appropriate current for the operation of the EMBR. The results of conventional pollutant removal showed that applying an electric current to the MBR approximately increased COD removal by 1.1 times, PO43- removal by 1.56 times, UV254 removal by 1.26 times, and turbidity removal by 1.11 times compared to the conventional MBR. The DCF removal efficiency increased from 43.90 % in the MBR process to 76.46 % in the EMBR. Membrane fouling was investigated through transmembrane pressure (TMP) monitoring, and the findings showed an increase in membrane usage time in EMBR compared to conventional MBR. Finally, the results explained that the application of current to MBR improves the removal of contaminants, mitigates membrane fouling, and reduces the residual DCF concentration.

Thin microporous polydimethylsiloxane membrane prepared by phase separation and its applications for cell culture

Animal experiments are often required for biological studies. However, in vitro cell culture models, such as cell-culture inserts and microphysiological systems, can provide a suitable alternative, making them essential tools in cell biology research, including the simulation of an organ environments closely related to the human body. Cell-culture inserts with porous membranes assist in recreating in vivo cell culture environments to study and process cell-culture assays. However, conventional cell culture membranes typically made of polyethylene terephthalate or polycarbonate cannot accommodate cell types that require deformable substrates. As such, this paper introduced a novel approach using spin-casting-assisted polymer-blend phase separation to create thin, flexible, and highly porous membranes for cell culture applications. Polydimethylsiloxane (PDMS) was selected as the material for the porous membrane, and polystyrene (PS) was used as a counter pair to induce phase separation with PDMS. PDMS facilitated the necessary reversible deformations during cell culture owing to its low elastic modulus. The thickness of the membrane and connectivity of the phase-separated PS domains can be adjusted, facilitating the fine-tuning of the pore size and density to improve the membrane performance. Therefore, this study successfully fabricated thin microporous PDMS membranes with improved performance over standard membranes for cell-culture inserts, namely a higher porosity, flexibility, and softness. The results of this study can enhance cell culture methodologies and contribute to a deeper understanding of cellular processes.

Exploring the impacts of steroid estrogens load and aeration intensity on the performance, membrane fouling characteristics, and bacterial community structure of the anoxic-oxic membrane bioreactor

Steroid estrogens (SEs) are typical endocrine-disrupting compounds, and they are inadequately eliminated in most wastewater treatment plants (WWTPs), contributing significantly to their environmental prevalence. In an effort to optimize the performance of membrane bioreactor (MBR) in mitigating SEs alike micropollutants, this study investigated the influences of influent loads of three typical SEs (estrone (E1), 17β-estradiol (E2), and 17α-ethynyestradiol (EE2)) and the aeration intensity on the pollutants removal performance, membrane fouling characteristics, and bacterial community structure in a lab-scale anoxic/oxic-MBR (A/O-MBR) process. The presence of SEs shed minimal impacts on the performance of A/O-MBR process as indicated by conventional water quality parameters due to gradual microbial acclimation. However, the presence and the rising input of SEs accelerated membrane fouling as a result of the enhanced EPS excretion and PN/PS ratio and the reduced floc size. The moderate aeration intensity was preferred from the perspectives of conventional pollutants removal, SEs biodegradation, biomass accumulation, and membrane fouling mitigation. Evolution of bacterial community structure and predominant genera were identified at different SEs loads and aeration intensities, with Candidatus Competibacter and Ferruginibacter detected as the predominant genera at different SEs input loads and Thiothrix, Azospira, and Saprospiraceae_norank at different aeration intensities with identical SEs input. The results demonstrated the potential of A/O-MBR as a promising barrier against SEs alike micropollutants through the regulation and control of aeration intensity.