Search Results (80)

This study presents a detailed energy and exergy analysis of two forward osmosis (FO) desalination systems: single-pass and regenerative configurations. Both utilize osmotic pressure from a concentrated draw solution to drive water transport through a semi-permeable membrane. The regenerative system includes extra components for draw solute recovery, which increases electrical energy consumption to 188.9 kW and slightly lowers water recovery to 54%, compared to 98 kW and 60% for the single-pass FO system. Equivalent work for desalination is 1.4 kWh/m³ for single-pass and 1.8 kWh/m³ for regenerative FO systems. Exergy analysis shows the distillation column as the largest contributor to exergy destruction in both systems, responsible for over 44% of losses. The regenerative system adds 57.9 MW of chemical exergy destruction in the regenerator. Physical exergy destruction mainly occurs in the reboiler and condenser, while chemical exergy destruction is dominant in the FO membrane unit and regenerator. These findings provide valuable insights for improving the efficiency and sustainability of FO desalination technologies. Full article

Produced water, a byproduct of oil and gas extraction, poses significant environmental challenges due to its complex composition and high salinity. Conventional treatment technologies often struggle to achieve efficient contaminant removal while maintaining long-term operational stability. Membrane-based separation processes, particularly forward osmosis (FO), offer a promising alternative due to their low hydraulic pressure requirements, high selectivity, and ability to mitigate fouling and scaling effects. This study fabricated and evaluated a novel dual-layer zwitterion-modified electrospun nanofibrous membrane for enhanced produced water (PW) treatment. The dual-layer design consists of a highly porous electrospun nanofibrous support layer for improved permeability and mechanical strength, coupled with a zwitterionic-modified selective layer to enhance antifouling properties and selective contaminant rejection. The zwitterionic surface modification imparts superior hydration capacity, reducing organic and biological fouling while improving water transport efficiency. The membranes are characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), contact angle and tensile strength measurements, and nuclear magnetic resonance (NMR) spectroscopy to assess their morphological, structural, and chemical properties. The performance evaluations demonstrated significantly higher water flux (up to 16.05 L m⁻² h⁻¹ for SPW (synthetic produced water) and 6.00 L m⁻² h⁻¹ for PW using NaBr) and excellent solid rejection (up to 96.02% for SPW and 88.90% for PW), reduced concentration polarization, and superior antifouling performance compared to conventional FO membranes. Experimental results from bench-scale trials demonstrate that this advanced membrane technology offers enhanced water recovery and contaminant removal efficiency, making it a viable solution for industrial-scale PW treatment and reuse. The findings underscore the potential of next-generation dual-layer FO membranes in promoting sustainable water resource management within the oil and gas sector while minimizing environmental impact. Full article

The growing scarcity of freshwater worldwide has increased interest in forward osmosis (FO) membranes as a promising solution for water desalination and wastewater treatment. This study investigates the enhancement of thin-film composite (TFC) FO membranes via the incorporation of carboxyl-functionalized multiwalled carbon nanotubes (COOH-MWCNTs) into the polyethersulfone (PES) support layer. The membranes were fabricated using a combination of phase inversion and interfacial polymerization techniques, with COOH-MWCNTs incorporated into the membrane support layers at different concentrations (0–0.75 wt.%). Comprehensive characterization was carried out using various analytical methods and mechanical testing to evaluate the physicochemical and structural properties of the membranes. The modified membranes demonstrated improved hydrophilicity, enhanced mechanical and thermal stability, and improved surface charge properties. Performance tests using a 1 M NaCl draw solution showed that the optimized membrane (0.5 wt.% COOH-MWCNTs) attained a 161% enhancement in water flux (7.48 LMH) compared to the unmodified membrane (2.86 LMH), while also reducing internal concentration polarization (ICP). The antifouling properties were also significantly improved, with a flux recovery rate of 91.92%, attributed to enhanced electrostatic repulsion as well as surface and microstructural modifications. Despite a moderate rise in reverse solute flux, the specific reverse solute flux (J_s/J_w) remained within acceptable limits. These findings highlight the potential of COOH-MWCNT-modified membranes in enhancing FO desalination performance, offering a promising option for next-generation water purification technologies. Full article

The scalability and processability of high-performance membranes remain significant challenges in membrane technology. This work focuses on optimizing the pilot-scale production of patterned polysulfone (PSf) ultrafiltration membranes using the spray-modified non-solvent-induced phase separation (s-NIPS) method on a roll-to-roll pilot line. s-NIPS has already been studied extensively at lab-scale to prepare patterned membranes for various applications including membrane bioreactors (MBR), reverse osmosis (RO) and forward osmosis (FO). Although studied at the lab scale, membranes prepared at a larger scale can significantly differ in performance; therefore, phase inversion parameters, including polymer concentration, molecular weight, and additive type (i.e., polyethylene glycol (PEG) or polyvinylpyrolidine (PVP)) and concentration, were systematically varied when casting on a roll-to-roll, 12″ wide pilot line to identify optimal conditions for achieving defect-free, high-performance, patterned PSf membranes. The membranes were characterized for their pure water permeance, BSA rejection, casting solution viscosities, and resulting morphology. s-NIPS patterned membranes exhibit 150–350% increase in water flux as compared to their reference flat membrane, thanks to very high pattern heights up to 825 µm and formation of finger-like macrovoids. This work bridges the gap between lab-scale and pilot-scale membrane preparation, while proposing an upscaled membrane with great potential for use in water treatment. Full article

As sensitive parts of the water treatment process, reverse osmosis (RO) membranes are the most important for desalination and wastewater treatment. But the performance of RO membranes deteriorates over time due to fouling, necessitating frequent replacements. One of the environmental challenges is the disposal of End-of-Life (EoL) RO membranes, which are made of non-biodegradable polymers. The reuse of EoL membranes as a sustainable approach for waste saving and resource efficiency has recently attracted considerable attention. The present work provides a comprehensive overview of the strategies for reusing EoL RO membranes as sustainable alternatives to conventional disposal methods. Furthermore, the fundamental principles of RO technology, the primary types and impacts of membrane fouling, and advanced cleaning and regeneration techniques are discussed. The conversion of EoL membranes into nanofiltration (NF), ultrafiltration (UF), and forward osmosis (FO) membranes is also covered in this review, as well as their uses in brackish water desalination, dye/salt separation, groundwater treatment, and household wastewater reuse. Environmental and economic benefits, as well as technical, social, and regulatory challenges, are also discussed. Finally, the review highlights innovative approaches and future directions for incorporating EoL membrane reuse into circular economy models, outlining its potential to improve sustainability and reduce operational costs in water treatment systems. Full article

The efficient removal of emulsified oil and trace organic pollutants via forward osmosis (FO) technology remains challenging due to limited water flux and membrane fouling. In this study, a series of metal oxide-modified PES-based composite FO membranes were fabricated and systematically evaluated to compare the effects of ZnO, Al₂O₃, and CuO nanoparticles on membrane structure and separation performance. The results demonstrated that the membrane modified with 0.04 g of ZnO nanoparticles achieved optimal synergy in terms of hydrophilicity, surface charge, and pore structure. The pure water flux increased from 5.48 L·m⁻²·h⁻¹ for the pristine membrane to 18.5 L·m⁻²·h⁻¹ for the ZnO-modified membrane, exhibiting a 237.5% increase in pure water flux compared to the pristine PES membrane, an oil rejection rate exceeding 97%, and over 95% rejection of typical negatively charged trace organic pollutants such as ibuprofen and tetracycline. Moreover, the ZnO-modified membrane showed excellent antifouling performance and structural stability in various organic solvent systems. This study not only optimized the interfacial chemistry and microstructure of the FO membrane but also enhanced pollutant repellence and the self-cleaning capability through increased hydrophilicity and surface negative charge density. These findings highlight the significant potential of ZnO modification for enhancing the overall performance of FO membranes and provide an effective strategy for developing high-performance, broadly applicable FO membranes for complex water purification. Full article

Membrane technologies are used in the production of potable water and the treatment of wastewater in the military forces, providing the highest level of contaminant removal at an energy-efficient cost. This review examines the integration and application of membrane technologies, including reverse osmosis, nanofiltration, ultrafiltration, electrodialysis and advanced hybrid systems, in the treatment of wastewater generated at military bases, naval vessels and submarines. Special emphasis is placed on purification technologies for chemically, biologically and radiologically contaminated wastewater, as well as on the recycling and treatment of wastewater streams by mobile systems used in military applications. Given the specific requirements of complex military infrastructures, particularly in terms of energy efficiency, unit self-sufficiency and reduced dependence on logistical supply chains, this work analyses the latest advances in membrane technologies. Innovations such as nanographene membranes, biomimetic membranes, antifouling membrane systems and hybrid configurations of forward osmosis/reverse osmosis and electrodialysis/reverse electrodialysis offer unique potential for implementation in modular and mobile water treatment systems. In addition, the integration and operational use of these advanced technologies serve as a foundation for the development of autonomous military water supply strategies tailored to extreme operational conditions. The continued advancement and optimization of membrane technologies in military contexts is expected to significantly impact operational sustainability while minimizing environmental impact. Full article

With the explosive growth in global lithium demand driven by the new energy industry, traditional lithium extraction methods face critical challenges such as resource scarcity, environmental pressure, and high energy consumption, necessitating sustainable alternatives. Under such circumstances, geothermal brine has emerged as a critical lithium resource, attracting significant attention due to advancements in efficient extraction technologies. This review establishes a comprehensive framework for analyzing geothermal lithium extraction technologies, with the following key contributions: an in-depth analysis of resource characteristics and development advantages, an innovative technical evaluation and performance comparison, and strategic pathways for technological synergy and industrial integration. This article reviews the global distribution and characteristics of lithium resources, analyzes the advantages and primary methods of geothermal lithium extraction, and examines key challenges such as high energy consumption and environmental impacts. Furthermore, future development directions are outlined. Currently, applicable technologies for geothermal lithium extraction include evaporation–crystallization, chemical precipitation, adsorption, solvent extraction, electrochemical methods, and membrane separation. Among these, membrane separation, particularly forward osmosis (FO), is identified as a pivotal research focus. The industrialization of geothermal lithium extraction and its integration with other industries are expected to shape future trends. This review not only provides critical insights and optimization strategies for geothermal lithium resource development, but also establishes a theoretical foundation for the green transition and sustainable utilization of resources in the global new energy industry. Full article

Energy-efficient and cost-effective water desalination systems can significantly replenish freshwater reserves without further stressing limited energy resources. Currently, the majority of the desalination systems are operated by non-renewable energy sources such as fossil fuel power plants. The viability of any desalination process depends primarily on the type and amount of energy it utilizes and on the product recovery. In recent years, membrane distillation (MD) and forward osmosis (FO) have drawn the attention of the scientific community because of FO’s low energy demand and the potential of MD operation with low-grade heat or a renewable source like geothermal, wind, or solar energy. Despite the numerous potential advantages of MD and FO, there are still some limitations that negatively affect their performance associated with the water–energy nexus. This critical review focuses on the hybrid forward osmosis–membrane distillation (FO-MD) processes, emphasizing energy demand and product quality. It starts with exploring the limitations of MD and FO as standalone processes and their performance. Based on this, the importance of combining these technologies into an FO-MD hybrid process and the resulting strengths of it will be demonstrated. The promising applications of this hybrid process and their advantages will be also explored. Furthermore, the performance of FO-MD processes will be compared with other hybrid processes like FO–nanofiltration (FO-NF) and FO–reverse osmosis (FO-RO). It will be outlined how the FO-MD hybrid process could outperform other hybrid processes when utilizing a low-grade heat source. In conclusion, it will be shown that the FO-MD hybrid process can offer a sustainable solution to address water scarcity and efficiently manage the water–energy nexus. Full article

As the demand for sustainable water and wastewater management continues to rise in both desalination and industrial sectors, there is been notable progress in developing Zero Liquid Discharge (ZLD) and Minimal Liquid Discharge (MLD) systems. Membrane technologies have become a key component of these systems, providing effective solutions for removing contaminants and enabling the recovery of both water and valuable resources. This article explores recent advancements in the design and operation of ZLD and MLD systems, discussing their benefits, challenges, and how they fit into larger treatment processes. Emphasis is given to membrane-based processes, such as reverse osmosis (RO), membrane distillation (MD), and forward osmosis (FO), as well as hybrid configurations, and innovative membrane materials. These advancements are designed to address critical challenges like fouling, scaling, high energy demands, and high brine production. The article also explores exciting research directions aimed at enhancing the efficiency and durability of membrane technologies in ZLD and MLD systems, paving the way for new innovations in sustainable water management across various industries. Full article

Water scarcity necessitates desalination technologies, yet their high energy demands and brine disposal challenges hinder sustainability. This research study evaluates the energy footprint and carbon emissions of thermal- and membrane-based desalination technologies, alongside Minimal/Zero Liquid Discharge (MLD/ZLD) frameworks, with a focus on renewable energy source (RES) integration. Data revealed stark contrasts: thermal-based technologies like osmotic evaporation (OE) and brine crystallizers (BCr) exhibit energy intensities of 80–100 kWh/m³ and 52–70 kWh/m³, respectively, with coal-powered carbon footprints reaching 72–100 kg CO₂/m³. Membrane-based technologies, such as reverse osmosis (RO) (2–6 kWh/m³) and forward osmosis (FO) (0.8–13 kWh/m³), demonstrate lower emissions (1.8–11.7 kg CO₂/m³ under coal). Transitioning to RES reduces emissions by 90–95%, exemplified by renewable energy-powered RO (0.1–0.3 kg CO₂/m³). However, scalability barriers persist, including high capital costs, RES intermittency, and technological immaturity in emerging systems like osmotically assisted RO (OARO) and membrane distillation (MD). This research highlights RES-driven MLD/ZLD systems as pivotal for aligning desalination with global climate targets, urging innovations in energy storage, material robustness, and circular economy models to secure water resource resilience. Full article

This review focuses on the use of membrane techniques to recover nutrients from the liquid fraction of digestate (LFD) and emphasizes their role in promoting the principles of the circular economy. A range of membrane separation processes are examined, including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO), membrane distillation (MD) and new tools and techniques such as membrane contactors (MCs) with gas-permeable membranes (GPMs) and electrodialysis (ED). Key aspects that are analyzed include the nutrient concentration efficiency, integration with biological processes and strategies to mitigate challenges such as fouling, high energy requirements and scalability. In addition, innovative hybrid systems and pretreatment techniques are examined for their potential to improve the recovery rates and sustainability. The review also addresses the economic and technical barriers to the full-scale application of these technologies and identifies future research directions, such as improving the membrane materials and reducing the energy consumption. The comprehensive assessment of these processes highlights their contribution to sustainable nutrient management and bio-based fertilizer production. Full article

Microalgae have attracted wide attention due to their extensive application potential. Dewatering is a necessary work for the application of microalgae, especially in biofuel production, where forward osmosis (FO) research is relatively advanced but still faces technical bottlenecks hindering large-scale commercialization. Based on the current research in recent years, the research progress in the causes and control of membrane fouling, the development of membrane materials and optimization of membrane structure, and the energy saving and efficiency of the process are reviewed in this paper. We found that different species of algae have direct effects on membrane fouling. Chlorella vulgaris has a low membrane fouling trend, but the mechanisms of fouling need further investigation. The material development and structure optimization of membranes are the main research methods to reduce membrane fouling, but there are still some defects, such as complicated preparation and low water flux, which are difficult to apply on a large scale. The research progress of reducing costs by using seawater, urine, fertilizer, etc. as new draw solutions (DS) is reviewed. At present, many aspects of FO microalgae dewatering technology are still not well understood, and future research should focus on scaling up the existing technologies. Full article

This work develops a comprehensive review of the main conventional and emerging desalination processes. It presents the state of knowledge of the most known and investigated techniques, highlights their advantages and drawbacks, and draws appropriate conclusions on their respective performances from various angles including their energy consumption and efficiency, environmental impacts, reliability, and flexibility in operations. This review reveals the recent large dominance and deployment of the reverse osmosis technology in the Gulf countries, mainly in Saudi Arabia; the importance of hybridization; and the slow penetration of promising processes including membrane distillation and forward osmosis into the industrial desalination market. In addition, this work aims to develop some comparison exercises between these processes using specific criteria. A cross approach allowing an easier comparison between various desalination processes could help identify the advantages and drawbacks of each technology and select the appropriate process. Therefore, various criteria allowing a clear picture to be drawn of the performance and capabilities of the main conventional and emerging desalination processes have been proposed in the frame of sustainable development. As an illustration of this general approach from sustainability prospects and considering specific weights for each proposed criterion for the case of Saudi Arabia, a comparison exercise reveals that the superiority of reverse osmosis (RO) is confirmed. Multiple effect distillation (MED) and membrane distillation (MD) processes are potentially competitive to RO while multi-stage flash (MSF) comes last due to several drawbacks. Full article

Forward osmosis (FO) technology, known for its minimal energy requirements, excellent resistance to fouling, and significant commercial potential, shows enormous promise in the development of sustainable technologies, especially with regard to seawater desalination and wastewater. In this study, we improved the performance of the FO membrane in terms of its mechanical strength and hydrophilic properties. Generally, the water flux (J_w) of polyisophenylbenzamide (PMIA) thin-film composite (TFC)-FO membranes is still inadequate for industrial applications. Here, hydrophilic polydopamine (PDA)@ zeolitic imidazolate frameworks-8 (ZIF-8) nanomaterials and their integration into PMIA membranes using the interfacial polymerization (IP) method were investigated. The impact of PDA@ZIF-8 on membrane performance in both pressure-retarded osmosis (PRO) and forward osmosis (FO) modes was analyzed. The durability and fouling resistance of these membranes were evaluated over the long term. When the amount of ZIF-8@PDA incorporated in the membrane reached 0.05 wt% in the aqueous phase in the IP reaction, the J_w values for the PRO mode and FO mode were 12.09 LMH and 11.10 LMH, respectively. The reverse salt flux (J_s)/J_w values for both modes decreased from 0.75 and 0.80 to 0.33 and 0.35, respectively. At the same time, the PRO and FO modes’ properties were stable in a 15 h test. The incorporation of PDA@ZIF-8 facilitated the formation of water channels within the nanoparticle pores. Furthermore, the J_s/J_w ratio decreased significantly, and the FO membranes containing PDA@ZIF-8 exhibited high flux recovery rates and superior resistance to membrane fouling. Therefore, PDA@ZIF-8-modified FO membranes have the potential for use in industrial applications in seawater desalination. Full article