Membrane Distillation System Research Articles

Experimental Investigation of Temperature Polarization near Membrane Surface During Air Gap Membrane Distillation Processes.

Temperature polarization is a critical factor influencing the performance of membrane distillation. The presence of temperature polarization causes the temperature of the fluid near the membrane surface to be different from that in the bulk region, reducing the effective temperature difference across the membrane and thus diminishing the transmembrane mass transfer driving force. This study investigates the monitoring of temperature polarization and its effects on the transmembrane mass transfer performance in a typical air gap membrane distillation system. A set of thermocouples within a feed module were employed to monitor and capture the development of the temperature polarization profile. The test results reveal that temperature polarization reduces the effective temperature difference across the membrane, leading to a certain difference between the theoretical estimation and experimental values of the mass transfer coefficient across the porous membrane. To address this issue, the temperature polarization factor was further analyzed as a metric to quantify the impact of temperature polarization on the transmembrane flux in membrane distillation, with a detailed discussion of its range and implications.

Performance prediction of vacuum membrane distillation system based on multi-layer perceptron neural network

Performance prediction of vacuum membrane distillation system based on multi-layer perceptron neural network

Evaluation of swirling flow phenomenon in direct contact membrane distillation

The global water crisis is growing so severe that there is a need for innovative technologies for effective desalination. The utilization of cutting-edge techniques for the treatment of seawater and saline water using membrane distillation (MD) has several advantages that are significant benefits. This study investigates how swirling flow configurations can improve the performance of Direct Contact Membrane Distillation (DCMD) modules. Swirling flow can be used to create turbulence, which lowers temperature polarization (TP) and concentration polarization (CP). This makes it easier for heat and mass to move through the system. An experimental DCMD system has been set up to study the effect of varying permeate flow rates and temperature differences on permeate flux. The results reveal that higher flow rates and temperature differences significantly enhance the overall performance, up to a limit. This study highlights the potential of swirling flow techniques to improve the efficiency and scalability of MD systems in a bid to enhance the desalination or treatment of water.

Permeate flux enhancement with dilute nanofluidic colloidal suspension in membrane distillation system

Permeate flux enhancement with dilute nanofluidic colloidal suspension in membrane distillation system

Data-driven models of a solar field used to power membrane distillation systems: A comparison study

Data-driven models of a solar field used to power membrane distillation systems: A comparison study

Global advancement of solar photovoltaic thermal technologies integrated with membrane distillation systems: a comprehensive review.

Energy is crucial to progress toward development, modernization, and economic prosperity. Energy and water are both crucial to human survival and play significant roles in the growth and development of society. The need for desalination has risen significantly as freshwater environments have declined. Membrane distillation can be used to successfully purify highly brackish water. The high energy needs of membrane distillation processes can be handled by low-grade heat sources such as solar photovoltaic thermal. In this paper, analyzing the several types of solar thermal sources, and exploring how the membrane distillation process could be configured to optimize performance on minimizing costs. This study also considered the various applications of this technology, its potential benefits, and the challenges that needs to be overcome for it to be successful. Finally, using solar photovoltaic thermal-based membrane distillation systems, to explore the membrane distillation existing implementation, as well as the challenges and potential benefits associated with it are reviewed. In this review article, both the benefits and drawbacks of desalinating water throughout the world using solar energy are analysed and a comprehensive overview of solar desalination technologies has been developed in recent years. Also, the most significant initiatives in solar desalination, including its economic and environmental impacts are reviewed in this paper.

Biomass-Derived Carbon and Carbon Nanofiber-Integrated Electrospun Janus Membranes: A New Frontier in Membrane Distillation.

Membrane distillation (MD) is an emerging desalination technique that uses low-grade energy to extract water vapor from saline solutions. In a thermally driven MD system, achieving a lower heat transfer and a higher mass transportation rate is desirable. To balance the trade-off between heat transfer and mass transportation, we developed novel dual-layered electrospun Janus nanofibrous membranes in this study, showing asymmetric wettability on each layer. The developed Janus membrane was constructed with a bottom hydrophilic layer composed of PVDF-co-HFP/biomass-derived jute carbon (JC) particles, and the top hydrophobic layer was formed using PH/carbon nanofibers (PH/CNF). The effect of distinct carbon nanoparticles on the prepared membranes was investigated by analyzing their chemical structure, morphology, water contact angle (WCA), pore size, porosity, thickness, liquid entry pressure, and mechanical and thermal stability. The hydrophobic layer of the optimized Janus membrane exhibited a WCA of 138 ± 1°, and the hydrophilic surface showed 72 ± 4°. Additionally, the optimized Janus membrane composed of a hydrophobic PH/0.5 wt % CNF layer and PH/0.5 wt % JC hydrophilic layer experienced an outstanding improvement in water flux (with 70 g L-1 of NaCl content), reaching to a value of 71.72 kg m-2 h-1 (∼162% improvement compared to the pristine PH membrane), while maintaining a salt rejection of >99.99% for 24 h of water gap membrane distillation. Notably, the optimum Janus PH-0.5CNF/PH-0.5JC membrane demonstrated an astonishing long-term stability with real seawater, exhibiting a remarkable flux of 78.42 kg m-2 h-1, which is ∼547% higher than commercially available PVDF membranes, while maintaining a salt rejection of 99.98% after 50 h. The proposed strategies provide a novel approach to fabricate an electrospun Janus membrane, and their performance highlights a strong potential candidate to be used in commercial water desalination plants.

Coupling CO2 capture process with electrochemically enhanced membrane distillation system for lithium-ion battery recovery: Reagent-Saving and environmental footprint reducing.

Coupling CO2 capture process with electrochemically enhanced membrane distillation system for lithium-ion battery recovery: Reagent-Saving and environmental footprint reducing.

Hybrid Mechanical Vapor Compression and Membrane Distillation System: Concept and Analysis.

The concept of integrating mechanical vapor compression (MVC) with direct contact membrane distillation (DCMD) is presented and analyzed. The hybrid system utilizes the DCMD to harvest the thermal energy of the MVC reject brine to preheat a portion of the seawater intake and simultaneously produce additional fresh water. Based on the operating temperature, the hybrid system requires specific energy consumption between 9.6 to 24.3 kWh/m3, which is equivalent to 25 to 37% less than the standalone MVC. Similarly, the freshwater production of the hybrid system can range between 1.03 and 1.1 kg/h, which is equivalent to a 3% and 10% increase relative to the standalone MVC when operating at brine temperatures of 50 and 90 °C, respectively. However, this enhancement is achieved at the expense of an average of 60% larger total surface area. This is partially due to the incorporation of the surface area of the MD modules and mostly to reduced temperature differences. Altering the permeate-to-feed ratio of the DCMD module led to a marginal change in the overall production without any enhancement in the compression power consumption. Increasing the MD module length by 50% resulted in a 3% enlargement in the overall production rate and a 10% reduction in power consumption. A modified hybrid structure that additionally utilizes the distillate heat is sought. A 5% increase in water production at the expense of a 45% rise in the specific compression energy of the modified structure over the original hybrid system is obtained.

Experimental Evaluation of a Direct Contact Membrane Distillation System Efficiency Under Single- and Double-Stage Cooling Modes

Experimental Evaluation of a Direct Contact Membrane Distillation System Efficiency Under Single- and Double-Stage Cooling Modes

Hydrogel‐Based Photothermal‐Catalytic Membrane for Efficient Cogeneration of Freshwater and Hydrogen in Membrane Distillation System

Abstract Photothermal‐catalytic (PTC) process is a promising way to produce freshwater and clean hydrogen by integrating solar‐driven desalination and water splitting. However, efficient solar spectrum utilization coupled with effective mass and thermal management poses key challenges in developing multifunctional PTC systems. Here, a highly stable hydrogel membrane (CdS/MX‐HM) that incorporates MXene and in‐situ generated CdS as the PTC materials into a customized vacuum membrane distillation (VMD) setup is demonstrated. The CdS/MXene composites utilize the full solar spectrum, with MXene contributing to photothermal ability and serving as a co‐catalyst to enhance photocatalytic performance, which are effectively integrated into the membrane system. These functional materials are immobilized within the hydrophilic PVA/chitosan hydrogel layer, which creates a supramolecular network that provides excellent stability and protection while offering an interface for PTC processes. Supported by the hydrophobic PTFE membrane substrate, the integrated system enables fast gas transfer to the permeate, completing the dual‐function design. Through systematic optimization of membrane structure and operational parameters, the PTC‐VMD system achieves a water flux of 1.63 kg m−2 h−¹ and a hydrogen production rate of 3099 µmol m−2 h−1 under one sun irradiation, demonstrating its potential as a sustainable solution for the water‐energy nexus challenge.

Mathematical and experimental study of the direct contact membrane distillation method for desalination using a hydrophobic electrospun nanofibers membrane

This paper examines the performance of a Direct Contact Membrane Distillation (DCMD) system experimentally and theoretically. The system uses a super hydrophobic electrospun nanofiber membrane to desalinate water. Investigations were carried out into how the feed concentration, feed flow rate, and feed temperature affected permeate flux. as system operating parameters to aid in comprehending the factors impacting the DCMD process. The application of DOE and Taguchi methods achieved statistical optimization of the DCMD process's performance. In addition, the study of mass and heat transport in DCMD was described by a theoretical model. While the feed concentration (0- 210 g/L) significantly affected flux, the feed's temperature (35-55 °C) and flow rate (0.2-0.6 L/min) mostly dominated the impact on system performance. The created model numerically solved the DCMD process using MATLAB software, describing it as a system of nonlinear equations. Various operating conditions were used to investigate the efficiency of the superhydrophobic electrospun nanofiber membrane in treating 210 g/L NaCl salt water. Changing the feed temperature and concentration affected the hypothetically suggested path across the membrane, according to the simulation results presented in this paper. Excellent agreement was observed between the experiment results and the constructed model's predicted results. Every instance maintained a high salt rejection rate (over 99.9%). The DCMD produced a gain output ratio (GOR) of 0.87 and a temperature polarization coefficient of 0.78 to 0.91. The system achieved a maximum thermal efficiency of 73.5%. The optimal parameters, which are 70 g/L, 0.6 L/min, and 55°C.

Modeling and experimental validation of nanophotonics-enhanced solar membrane distillation technology for treating reverse osmosis brine

A novel, cost-efficient Nanophotonic Enhanced Solar Membrane Distillation (NESMD) system, a solar-driven water desalination technology, was studied. The system features a photothermal membrane acting as a solar collector for water distillation, thus eliminating the need for an external condenser. To address the system’s vulnerability to thermal losses, a comprehensive mathematical model was developed and validated against real-world experimental data. This model represents intricately coupled heat and mass transfer within a sweeping-air NESMD system, incorporating heat loss considerations. The modeling strategy involved dividing the NESMD module into sub-cells and implementing a finite difference method for detailed analysis. This led to a series of nonlinear simultaneous equations, which were resolved via computational code using MATLAB software. The developed NESMD model exhibited commendable conformity to experimental data, exhibiting a relative percentage error of less than 10% for average permeate flux and identifying thermal losses as high as 63%. Depending on the operating conditions, heat transferred to the surroundings takes the lead among the heat loss contributors at higher feed rates (up to 25%), whereas heat conduction across the membrane dominates (up to 42%) thermal losses at low feed rates. The study established an exponential correlation between permeate production and solar energy, with a heat transfer coefficient ranging from 9.5 to 30 W m−2 K−1 and a coefficient of determination of 0.96. An integral part of this work includes calculating solar energy utilization and clarifying the system’s performance. Furthermore, this study examines the influence of diverse operational and geometric parameters, providing insights into enhancing production rates. Hence, an increase in feed layer thickness enhances freshwater production by 7%. Due to the intensification of solar irradiance, freshwater production increased ninefold, and specific energy consumption decreased by 134 kW hr m−3. This research underscores the potential of NESMD for sustainable desalination, providing a validated model that lays the groundwork for future advancements in membrane distillation technology.

The optimum location of vapor compressor in multistage vacuum membrane distillation system

The optimum location of vapor compressor in multistage vacuum membrane distillation system

System Dynamics Modeling of Scale Formation in Membrane Distillation Systems for Seawater and RO Brine Treatment.

To overcome the limitations of traditional Reverse Osmosis (RO) desalination, Membrane Distillation (MD) has gained attention as an effective solution for improving the treatment of seawater and RO brine. Despite its potential, the formation of inorganic scales, particularly calcium sulfate (CaSO4), continues to pose a major challenge. This research aims to explore the scaling mechanisms in MD systems through a combination of experimental analysis and dynamic modeling. Using real seawater and RO brine as feed sources, the scaling behavior was examined under various operational conditions, such as temperature and feed concentration. Optical Coherence Tomography (OCT) was utilized to monitor the real-time development of fouling layers, offering valuable insights into surface crystal formation processes. A System Dynamics Model (SDM) was created based on the experimental data to predict flux decline trends with precision. The model correlated well with experimental observations, highlighting key factors that drive scaling severity. This integrated approach deepens our understanding of scaling dynamics and provides actionable strategies to mitigate fouling in MD systems, thereby enhancing the efficiency and stability of MD desalination operations. Ultimately, this study underscores the potential of combining OCT with system dynamics modeling as a powerful approach for visualizing and validating scaling processes, offering a practical framework for optimizing MD performance and contributing to more sustainable desalination practices.

Correction: Theoretical Investigation into the Dynamic Performance of a Solar-Powered Multistage Water Gap Membrane Distillation System

Correction: Theoretical Investigation into the Dynamic Performance of a Solar-Powered Multistage Water Gap Membrane Distillation System

Sustainable desalination through hybrid photovoltaic/thermal membrane distillation: Development of an off-grid prototype

Global freshwater scarcity is a critical challenge, particularly severe in remote Australian communities where seawater intrusion and aquifer salinisation exacerbate the need for alternative water resources. Conventional desalination technologies are energy-intensive and unsuitable for rural areas. This study introduces a novel, off-grid, sustainable desalination solution utilising solar-integrated membrane distillation (MD) technology. An innovative, stand-alone prototype combining a hybrid photovoltaic/thermal (PV/T) system with direct contact MD (DCMD) has been designed and developed. This fully integrated PV/T collector efficiently supplies the thermal and electrical energy required for the MD process. The photovoltaic panel generates the necessary electrical energy, while the heat from the PV panel warms the MD system’s feed solution, enhancing overall efficiency through the solar cell cooling effect. In addition, an innovative fan-cooled radiator equipped with two DC fans with a low power consumption rating was designed and customized to be applied as MD system cooling medium within the outdoor setting. The concept development and feasibility of the system are explored in detail through a comprehensive experimental investigation employing an innovative and practical approach to design and examine the integrated hybrid solar MD unit. This unique system was designed, constructed, and tested under dynamic outdoor conditions, during the summer season in Melbourne, to assess the integration strategy and evaluate its long-term operational performance. The performance of the integrated PV/T-MD system was evaluated using two commercial hydrophobic membranes with different pore sizes under various outdoor conditions and PV/T fluid flow rates. Key performance metrics analysed include solar irradiance intensity, temperature profiles of the PV/T panel and MD module, power, current and voltage profiles of the unit components, permeate flux, specific water productivity (SWP) and the thermal (ηthermPV/T) and electrical (ηelecPV/T) efficiencies, along with the gained output ratio (GOR). Comprehensive experimental assessments in indoor and outdoor settings were undertaken to confirm the technical viability of the system. The study demonstrates the feasibility of such systems through real-world trials and addresses key challenges in energy efficiency and internal heat recovery. The experimental trials demonstrated permeate flux values ranging between 8–16 kg/m2h outdoors, compared to 22–30 kg/m2h indoors, reflecting the impact of fluctuating environmental conditions. The system’s power consumption was measured 130–140 W, about one-third of the PV/T power rating. The maximum power generation reached 280 W in battery charging mode. achieving a maximum ηthermPV/T of 20 % and an ηelecPV/T of 18 %. Additionally, the cooling effect of the PV/T panel resulted in a 1.5–2 °C temperature reduction, improving electrical power output by 0.8–1.2 %. The findings highlight the significant potential of the system in providing reliable and efficient freshwater production in remote, off-grid communities, offering a scalable solution to address global water scarcity challenges.

Solar-Driven ThinAir Gap Membrane Distillation witha Slippery Condensing Surface

Membrane-based desalination is essential for mitigatingglobalwater scarcity; yet, the process is energy-intensive and heavily relianton fossil fuels, resulting in substantial carbon emissions. To addressthe challenges of treating seawater, produced water, brackish groundwater,and wastewater, we have developed a thin air gap membrane distillation(AGMD) system featuring a novel slippery condensing surface. The quasi-liquidslippery surface facilitates efficient condensate water droplet removal,allowing for the implementation of a 1 mm thin air gap. This advancementhas led to a 2-fold increase in permeate flux without lowering thethermal efficiency while preventing permeate flooding. Furthermore,the thin AGMD system, employing a cost-effective zirconium nitride/poly(vinylidenefluoride) (ZrN-PVDF) composite membrane, has been demonstrated forsolar-driven desalination. Experimental results indicate that reducingthe air gap from 2 to 1 mm enhances the permeate flux by 150%.

Development of membrane distillation powered by engine exhaust for water desalination

Development of membrane distillation powered by engine exhaust for water desalination

Innovative solar-assisted direct contact membrane distillation system: Dynamic modeling and performance analysis

Innovative solar-assisted direct contact membrane distillation system: Dynamic modeling and performance analysis