A survival analysis framework for predicting gypsum scaling risk in dynamically concentrating desalination systems.

Nonwoven materials, characterized by high porosity, tunable fiber architecture, robust mechanical strength, and versatile surface functionalizability, have emerged as highly promising platforms for next-generation seawater desalination. This review comprehensively examines the structural design strategies and performance-regulation mechanisms of nonwoven membranes across major desalination technologies, including reverse osmosis (RO), forward osmosis (FO), membrane distillation (MD), and solar-driven interfacial evaporation (SIE). Particular emphasis is placed on the synergistic influence of fiber diameter, orientation, porosity, and multilayer composite configurations in determining key performance metrics, including water flux, salt rejection, wetting resistance, antifouling behavior, and long-term operational stability. Furthermore, we summarize recent advances in nonwoven fabrication techniques, including melt blowing, electrospinning, and centrifugal spinning, and discuss their integration with emerging functionalization approaches such as plasma modification, nanoparticle and 2D-material incorporation, polymer blending, and sustainable bio-based materials. By aligning nonwoven material design with the physicochemical requirements of different desalination pathways, this review highlights the technological potential of nonwoven membranes to enable high-efficiency, low-carbon, and environmentally sustainable desalination systems.

Electrochemical methods for carbon capture potentially have the advantage of low cost and low energy consumption. The practical applicability of pH-swing carbon capture processes driven by proton-coupled redox-active molecules has been limited by the sensitivity of reduced molecules to oxidation by O₂. In those processes, for CO₂ capture the molecules are reduced, basifying the electrolyte; the electrolyte containing the reduced molecules is exposed to air or flue gas containing CO₂ but also containing enough O₂ to oxidize the molecules. O₂ sensitivity would not be problematic if the electrolyte that captures CO₂ contains the oxidized form of the molecule instead; this can be accomplished by switching from an electron-driven system to an ion-driven system. We report the development and performance of a two-chamber flow cell incorporating a reverse-bias bipolar membrane (BPM) and non-proton-coupled redox-active molecules for ion-driven pH-swing. When using ferri/ferrocyanide electrolytes in this cell with a BPM, the cell pH can be spatially swung with the oxidized side basified for CO₂ capture and the reduced side acidified for release. Buffering agents and cell rebalancing mediators improved the efficiency and stability of the system. This work points out an alternative way of employing redox couples for electrochemically-powered pH swings.

The technological and economic efficiency of membrane water purification installations depends largely on the quality of the medium supplied to the devices carrying out the process. For typical technological solutions of desalination and demineralization systems, consisting of reverse osmotic membranes followed by nanofiltration membranes and electrodeionization units, pre-treatment of the feed water is required to meet the requirements of osmotic membrane manufacturers. The preliminary treatment of water aims to limit the phenomenon of membrane fouling, which is mainly caused by suspended solids, colloidal substances, and natural organic matter present in the water. The paper presents the results of research conducted in the technical coagulation/flocculation with sand ballasted sedimentation system followed by ultrafiltration units, used as preliminary water purification before osmotic membranes. Standard monitoring measurements were unable to detect situations where the process parameters deviated from the values determined during jar tests. Additionally, the obtained results of the research showed that coagulation/flocculation process can be conducted according to the criterion of minimizing the pressure loss during the filtration cycle and the strategy of maximizing pre-treatment effectiveness preceding ultrafiltration membranes. The condition for ensuring such parameters is the use of appropriate tools allowing for effective operational monitoring of the process. The results of the research on the application of a simple vacuum filtration test showed that it is a particularly good tool for monitoring and controlling the operational parameters of coagulation. During the research, high correlation was shown between the filtration time values of samples and the quality of the raw water feeding the treatment system, which affected the subsequent course of ultrafiltration. Similar dependencies were observed in clarified water supplied to UF membranes.

We introduce a stimulated Raman scattering (SRS) methodology designed for rapid, real-time, and in situ monitoring of RO membrane scaling adapted for bench-scale desalination flow cells. The methodology can provide new insights into membrane scaling dynamics by offering time-resolved reflection imaging of inorganic crystal growth, coupled with chemical identification from Raman spectral data. These capabilities allow for direct local measurement of the membrane surface area covered by different scalants as well as an approximation of the scalant volume using three-dimensional, integrated Raman intensity. The 2D and 3D SRS results obtained from CaSO4 scaling experiments are compared to and are in reasonable agreement with those provided by confocal microscopy. The real-time physical and chemical characterization capabilities presented here could be extended to study combinations of inorganic, organic, and biological fouling. Overall, the SRS methodology represents an advancement in real-time sensing of membrane fouling that offers the potential for improved operation, lower cost, and more resilient RO membrane systems for sustainable water management.

Faradaic deionization (FDI) using intercalation materials with cation-blocking membranes shows promise for energy-efficient desalination. Recently, we demonstrated for the first time the use of a symmetric FDI cell comprising two nickel hexacyanoferrate electrodes separated by an anion-exchange membrane to desalination feeds with seawater salinity down to near freshwater salinity at low energy consumption (Energy Environ. Sci., 2023, 16, 3025). However, reliance on ion-exchange membranes (IEMs) greatly increases the capital cost of FDI, limiting widespread adoption and commercialization. Herein, we investigate the desalination performance of a symmetric FDI cell that uses nanofiltration membranes as separators. The dynamic salt depletion/enrichment mechanism of the cell renders a salt removal that depends on a characteristic time constant and a Damköhler number, which represents the ratio of the rate of salt depletion caused by cation intercalation to the rate of salt diffusion through the NF membrane. This theory predicts that such an IEM-free symmetric FDI cell can produce freshwater from brackish water, though not from seawater. Experimental validation demonstrates the ability of the cell to desalinate 5 g/L NaCl and 3.2 g/L of Instant OceanÒ containing multiple salts to freshwater (< 1 g/L) and drinkable water (< 0.5 g/L), respectively. The cell exhibits a volumetric specific energy consumption of 1.4 – 2.2 kWh/m3, which is comparable to brackish water reverse osmosis, electrodialysis, or membrane capacitive deionization. Controlled experiments using IEMs reveal that salt diffusion through the NF membrane consumed 35 – 50% of the total charge passed to the cell, decreasing with increasing currents, whereas 25 – 40% of the charge is lost by other processes, which increases with currents. Unexpectedly, water recovery (WR) is shown in IEM-free SFDI to increase with the amount of charge transferred during batch-type experiments, contrasting with the usual decrease of WR that accompanies using IEMs.

Creating a feasible membrane for treating stable emulsion wastewater with submicrometer-sized oil-in-water droplets is significant but constrained by low efficiency and high energy consumption. Herein, an innovative reverse beetle-like nanofibrous membrane with hybrid wettability was first constructed by a nonsolvent-induced phase separation technique. The obtained membrane consists of hydrophobic/underwater oleophilic submicrometer-sized humps and a hydrophilic/underwater oleophobic nanofibrous substrate, which endows the membrane with excellent capacity for tiny oil droplet capture and fast water permeation. Benefiting from the fascinating hybrid wettability, this membrane can effectively separate various oil-in-water emulsions with submicron-sized droplets and demonstrated a promising separation efficiency (≥99.0%) and a high permeation flux (506 L m–2 h–1) even when driven by gravity (∼1 kPa). This work provides a promising approach to develop next-generation membranes integrating high separation efficiency and low energy consumption for oil–water separation.

The demand for clean and renewable water sources continues to increase as water scarcity increases. This review explores the potential of advanced materials that add to water harvesting and treatment processes to reduce impending dangers. This review starts with assessing traditional water harvesting methods, spring development, fog collection, and desalination. The AWG system operates in three main steps: air is drawn in by solarpowered fans and filtered, water vapor is absorbed by special materials, and then solar heat converts the vapor into pure water. A mineral cartridge enriches the water with calcium and magnesium for better taste, and a large tank stores the water for future use. Sorbent materials like MOFs, silica gel, and zeolites play a key role by capturing atmospheric moisture until heated to release water all their strengths and weaknesses. This article describes newly emerging nanomaterials such as zero-valent iron nanoparticles, carbon nanotubes, and photocatalysts with increased contaminant removal and energy efficiency. Bioinspired materials from nature, such as desert spider silk and beetles, are described for innovative water harvesting. Finally, the overview compares membrane-based technologies such as reverse osmosis and membrane bioreactors according to their significance in modern-day water purification systems. By integrating recent advancements and identifying core challenges, the present review presents a broader view of how the evolution of sustainable, efficient, and scalable water treatment technologies is promoted by the use of advanced materials. In conclusion, the ability of AWH to supply SMDW (safely managed drinking water) to a billion people was demonstrated. Using Google Earth Engine 13, the evaluation presents a fictitious 1-meter-square device with a (specific yield) SY profile of 0.2 to 2.5 liters per kilowatt-hour (0.1 to 1.25 liters per kilowatt-hour for a 2-metersquare device) for 30% to 90% relative humidity. An average person's daily drinking water needs of five liters might be satisfied by such a device.

Following on from a circular economy in water, membrane technologies can play a role in resource recovery and high-quality water production but should also consider membrane industry circularity. Anaerobic membrane bioreactors (AnMBRs) are being used for advanced wastewater treatment, and their applications are growing due to advantages like lower sludge volume, better permeate quality, and the generation of biogas. High-Rejection (HR) AnMBRs retain a higher fraction of dissolved and particulate components to further promote resource recovery and obtain improved effluent quality. With the development of membrane technologies, end-of-life (EOL) membrane recycling is emerging for various applications. The feasibility of transforming EOL Reverse Osmosis (RO) membranes into ultrafiltration (UF)- and nanofiltration (NF)-like membranes and applying these membranes to submerged HR-AnMBR applications was evaluated. A small pilot AnMBR with granular biomass was operated with EOL RO membranes converted to submerged UF- and NF-like membranes and compared to commercial microfiltration (MF) membranes. UF- and NF-like plates were constructed, characterized, and introduced step-by-step into the AnMBR by the substitution of MF plates. A chemical oxygen demand (COD) removal study showed that while 77% removal of COD was possible with MF membranes, improved COD removal (i.e., 81.40% and 88.39%) was achieved using UF-like and NF-like membranes, respectively. Because of the higher retention of salts of the NF-like membrane, the salinity in the membrane bioreactor increased from 1300 to 1680 µS·cm−1 but stabilized quickly and without a negative impact on system performance. Even without cleaning, minimal fouling and flux decline were observed for all tested configurations thanks to the use of granular biomass and low permeation flux. Permeate flux in the case of the NF-like membrane was slightly lower due to the required higher pressure. The present study demonstrated that the EOL-RO membranes may find applications in HR-AnMBRs to achieve superior permeate quality and move toward circular membrane processes.

This study serves as a proof of concept for the evaluation of two membrane technologies, reverse osmosis combined with membrane distillation, for the recovery of N-methylmorpholine N-oxide (NMMO) and water from generated wastewater by the textile manufacturing “Lyocell process”. This method utilizes NMMO to dissolve cellulose for the production of cellulosic yarn, resulting in wastewater that contains 1–2 %w/w NMMO. After an initial pretreatment to remove suspended solids, followed by a mixed ion-exchange resin, the stream was fed into a reverse osmosis membrane unit, concentrating the solution to approximately 10 %w/w NMMO. Following this step, the RO concentrate was introduced to a DCMD setup equipped with a PTFE microporous membrane, achieving a final concentration of a 70.5 %w/w NMMO aqueous solution, which is considered suitable for reuse. The main contribution of the present study is to establish, in principle, that the newly proposed method can be a modular and scalable alternative to the dominant multi-stage evaporation technologies.

Oily wastewater, a major byproduct of petroleum oil and gas production, poses serious environmental risks if not effectively treated. This review analyses the composition of oily wastewater, assesses current treatment methods, and explores strategies to improve efficiency while reducing capital and operational costs. Data corroborated from this work suggests that integrated treatment systems are more effective than single-method approach. Membrane-based technologies such as reverse osmosis (RO), forward osmosis (FO), and membrane distillation (MD) show promise in improving pollutant removal and energy efficiency. However, persistent challenges such as membrane fouling, high capital and operational costs, and membrane stability necessitate further innovation in materials development and hybrid system design. This review highlights the potential of well-designed hybrid systems for offshore oily wastewater treatment. Such systems can significantly enhance contaminant removal while minimising energy consumption and operational costs. Overcoming technical challenges and advancing membrane technologies will be essential for more sustainable and cost-effective oily wastewater treatment.

Integration of reverse osmosis and membrane distillation for fluoride removal from groundwater aiming at a zero-waste discharge process

Desalination plays a critical role in addressing global water scarcity, yet brine disposal remains a significant environmental challenge. This study evaluates a minimal liquid discharge (MLD) membrane-based system integrating high-pressure reverse osmosis (HPRO) and membrane distillation (MD) for brine treatment, with a focus on the Eastern Mediterranean. A techno-economic assessment (TEA) was conducted to analyze the system’s feasibility, water recovery performance, energy consumption, and cost-effectiveness. The results indicate that the hybrid HPRO-MD system achieves a high water recovery rate of 78.65%, with 39.65 m3/day recovered from MD and 39 m3/day from HPRO. The specific energy consumption is 23.2 kWh/m3, with MD accounting for 89% of the demand. The system’s cost is USD 0.99/m3, generating daily revenues of USD 228 in Cyprus and USD 157 in Greece. Compared to conventional brine disposal methods, MLD proves more cost-effective, particularly when considering evaporation ponds. While MLD offers a sustainable alternative for brine management, challenges remain regarding energy consumption and the disposal of concentrated waste streams. Future research should focus on renewable energy integration, advanced membrane technologies, and resource recovery through brine mining. The findings highlight the HPRO-MD MLD system as a promising approach for sustainable desalination and circular water resource management.

ObjectiveThis study primarily aimed to investigate human papillomavirus (HPV) infection in males and to evaluate its effect on semen parameters, fertility and partner HPV infection status.MethodsA total of 624 men who visited the West China Second Hospital of Sichuan University between October 1, 2019, and September 30, 2023, were included. HPV DNA was detected in exfoliated cells from the male genitalia using polymerase chain reaction (PCR) and reverse membrane hybridization to analyze the relationship between HPV infection and semen parameters. Furthermore, we retrospectively reviewed medical records of the participants and their partners to collect data on HPV infection and fertility outcomes.ResultsThe overall prevalence of HPV infection was 43.8% (273/624), with single-genotype infections accounting for a significantly higher proportion (59.3%, 162/273) than multiple-genotype infections (40.7%, 111/273). The five most prevalent HPV genotypes were HPV52, HPV16, HPV51, HPV58, and HPV42. High-risk (HR) genotypes accounted for most infections (79.5%, 217/273). Among 377 men who underwent semen analysis, HPV-positive individuals exhibited significantly reduced sperm motility and normal morphology compared to HPV-negative individuals (p<0.001). Furthermore, HPV infection was associated with increased sperm DNA fragmentation (p=0.007). Males co-infected with Ureaplasma urealyticum and Chlamydia trachomatis showed significantly lower total sperm counts (×106) (p=0.025) and DFI values (p=0.038) than those without co-infection. Partner data were available for 416 of the 624 men. In these couples, female HPV infection was significantly associated with male HPV status (p=0.038), particularly for HR-HPV (p=0.049). Male HPV-negative status was associated with a higher rate of normal fertility (p<0.001).ConclusionOur findings indicate that male genital HPV infection is common and may adversely affect semen quality, fertility, and increase the risk of HPV transmission to sexual partners.

Ion-exchange membranes (IEMs) that separate cation-intercalation electrodes in symmetric Faradaic deionization (SFDI) increase the capital cost of desalination. We experimentally test SFDI cells that use nanofiltration (NF) membranes instead. Theory is first used to contrast the rate-dependent salt depletion in IEM-free SFDI with IEM-based SFDI. Theory reveals that salt removal scales directly with the intercalation-induced cation-depletion rate relative to the membrane's cation diffusion flux by including the following effects: a current efficiency λ for parasitic electrode processes and a permeance Pm,+ and transference number tm,+ for membrane cation transport. Fitting to experiments indicates that bulk-electrolyte ion transport in the NF membrane's support layer (250 μm) dominates over active-layer ion transport (∼100 nm). An IEM-free SFDI flow cell using embedded, microinterdigitated flow fields was shown to desalinate feeds using 85 mM NaCl or 3.2 g/L of Instant Ocean synthetic salt. The cell produced either freshwater or drinkable water using 1.4-2.2 kWh/m3 at parity with reverse osmosis, electrodialysis, and membrane capacitive deionization. Water recovery was shown in IEM-free SFDI to increase with the charge transferred during batch-type experiments, contrasting its usual decrease with IEMs. Theory further suggests that NF membranes minimize concentration polarization relative to IEMs, decreasing mineral-scaling potential.

Global problems related to scarcity of clean water and water pollution have created an urgent need for effective solutions. Rapid urbanization and inexorable population growth have exacerbated this situation, increasing demand for clean water while decreasing its availability. In responding to this challenge, desalination technologies such as reverse osmosis (RO) and membrane processes have been considered as promising solutions although they are still faced with technological obstacles and large capital investments. In addition, concerns about water pollution by organic pollutants and bacteria have encouraged the development of effective wastewater treatment methods, including the use of conventional ozonation with membrane contactors and UV light. This research aims to explore new approaches to water treatment, including the use of membrane technology, conventional ozonation, and innovative disinfection methods such as UV light, with the hope of contributing to solving global problems related to clean water and water pollution. Through a series of comprehensive methodological steps, this research highlights the potential of these technologies to improve water quality and reduce contamination in a variety of application contexts.

The relevance application of dye cannot be overemphasized in our vicinity today, ranging from paintings, textiles, artistic purposes. Also, several other industrial applications including the cosmetics, leather, paper and even food industry. Notwithstanding its wide application, research has shown that the production of waste water containing synthetic dyes are deleterious to the environment and the ecosystem and therefore needs to be removed for the safety of the ecosystem. Several techniques like reverse osmosis, membrane filtration and coagulation can be used for removal of dyes. Some of these methods, despite their efficiency in wastewater treatment, they are expensive and sometimes complex to set up, therefore there is need for cheaper, affordable and simple method of wastewater treatment. Adsorption, mostly with waste biomass has proven to be a good and inexpensive method of dye removal from waste water. Therefore, this article reviewed adsorption of methylene blue dye unto sandbox seed biosorbent in a fixed bed continuous adsorption column. This review shows that there is still more to be done in terms of combining two or more different approaches in predicting and modelling adsorption of methylene blue removal from effluent water in order to obtain optimum result from treated water.

Elevated fluoride levels in drinking water pose a significant health risk for communities relying on groundwater in the Ethiopian Central Rift Valley. This study aims at characterizing real groundwater samples from the Ethiopian Central Rift Valley and evaluating the performance of an integrated membrane process based on reverse osmosis (RO) and membrane crystallization (MCr) for fluoride removal and its recovery as mixed fluoride salts. Groundwater analysis revealed fluoride concentrations of 20.8 mgL−1 at the Meki-01 site and 22.7 mgL−1 at the Meki-02 site, both exceeding the WHO guideline of 1.5 mgL−1. In addition, total dissolved solids exceeded 1000 mgL−1 at both sites, classifying the water as brackish. A commercial RO membrane demonstrated excellent fluoride and ion rejection, with fluoride removal rates exceeding 99%. The total dissolved solids (TDS) removal efficiency reached 89%. The mean water permeability of the membrane was 4.52 Lm−2h−1bar−1. The retentate produced in the RO unit reached a concentration of 70 mgL−1, which was then treated using osmotic membrane distillation–crystallization (OMD-Cr) and/or vacuum membrane crystallization (VM-Cr). This process facilitated the recovery of mixed salts while achieving an almost zero-liquid discharge. The study confirms the successful removal of fluoride and its recovery as mixed salt, along with the recovery of water in an environmentally friendly and manageable way.

This study explores the compaction behavior of thin-film composite reverse osmosis (TFC RO) membranes for different combinations of transmembrane pressure (TMP) and transmembrane water flux. Operating a crossflow system at constant feed pressure (60 bar) but different feed solution osmotic pressures enabled adjusting the TMP─the difference between hydraulic and osmotic pressure─and water flux. The extent of membrane compaction increases as TMP (and flux) increases. Both commercial and hand-cast TFC RO membranes showed substantial compaction at high TMP (up to 30% compaction at 50 bar TMP) compared to less than 10% at 10 bar TMP. Scanning electron microscope (SEM) images reveal a direct relationship between TMP and polysulfone (PSU) support layer compaction, while molecular dynamics (MD) simulations confirmed decreased porosity and reduced thickness in the polyamide (PA) active layer as TMP increases. Combined findings from wet-testing and MD simulations confirm a hydraulic pressure drop occurs across both the PA active layer and the meso-to-macro-porous support layer; higher TMP exacerbates compaction in both layers resulting in lower water permeability but higher water flux, observed salt rejection, and salt permeability. Transitioning from high TMP to low TMP or vice versa did not notably alter the extent of membrane compaction. This observation is attributed to the highly cross-linked PA active layer's ability to recover after pressure is released, whereas the compaction in the PSU support layer is largely irreversible. While TMP dictates the overall pressure gradient, our findings suggest that flux-induced frictional forces play a crucial role in compaction dynamics. Specifically, higher flux generates additional drag forces on the polymer matrix of both the PSU support layer and the PA selective layer, intensifying structural deformation. Overall, our findings offer critical insights into the mechanisms of membrane compaction, providing a foundation for optimizing RO membrane performance and advancing next-generation membrane technologies.

Experimental investigation of the performance of a seawater Reverse Osmosis spiral wound membrane under variable feed water temperature