Freshwater Production Research Articles

Optimization and techno-economic-environmental assessments of a biomass-powered multi-generation plant for hydrogen and freshwater production

Optimization and techno-economic-environmental assessments of a biomass-powered multi-generation plant for hydrogen and freshwater production

Heat Re-process approach and thermally integrated renewable energy system for power, compressed hydrogen, and freshwater production; ANN boosted optimization and techno-enviro-economic analysis

Heat Re-process approach and thermally integrated renewable energy system for power, compressed hydrogen, and freshwater production; ANN boosted optimization and techno-enviro-economic analysis

Solar-driven evaporation based on regulation salt crystallization behavior for high-efficiency freshwater production and salt collection

Solar-driven evaporation based on regulation salt crystallization behavior for high-efficiency freshwater production and salt collection

Effect of wind speed on evaporation rate in air conditioner based desalination units

Due to environmental changes, ensuring access to clean water is challenging for many regions. This study examines how wind speed influences seawater evaporation rates in a desalination system. Conducted indoors, the research varied wind speeds (0.6 m/s, 0.7 m/s, and 0.8 m/s) while maintaining a consistent temperature. A modified window Air Conditioner (AC) served as the evaporation unit, with its condenser immersed in water to utilize released heat, and its evaporator used as a condenser. Water temperature was maintained at 60-70°C. Results demonstrated a significant increase in evaporation rates with higher wind speeds. The strong correlation between experimental and theoretical results underscores wind speed as a critical factor in enhancing freshwater production efficiency from seawater. These insights inform the design of more effective desalination systems, offering potential solutions to water scarcity challenges in vulnerable regions

In-depth analysis of an inclined solar desalination plant for optimal orientation by the conventional systems modification: toward low-carbon emission and sustainability

Abstract This study examines the use of computational fluid dynamics to analyze and simulate the 3D modeling of a solar desalination plant with a single slope design. It aims to optimize large-scale desalination by investigating factors like glass cover angle and fin placement. Results show that a 15° glass cover produced the most freshwater (0.2957 kg/m2·h), while a 60° angle decreased production by 8.63%. Adding fins increased freshwater production by 53.32% and improved heat transfer efficiency. These findings contribute to developing an optimized solar desalination model to enhance efficiency, reduce energy consumption, and lower carbon emissions.

Experimental Investigation on Thermo-Economic Analysis of Direct Contact Membrane Distillation for Sustainable Freshwater Production

Treatment of extremely saline water such as the brine rejected from reverse osmosis water desalination plants, and produced water from shale oil and non-conventional gas extraction, is considered a global problem. Consequently, in this work, hollow fiber membrane distillation (HFMD) is experimentally evaluated for desalinating extremely saline water of a salinity ranging from 40,000 to 130,000 ppm. For the purpose of comparison, the HFMD is also tested for desalinating brackish (3000–12,000 ppm) and sea (25,000–40,000 ppm) water. Firstly, the HFMD is tested at two values of feed water temperature (65 and 76 °C) and flow rate (600 and 850 L/h). The experimental results showed that the HFMD productivity significantly increases when the temperature of feed water increases. Increasing the feed water flow rate also has a positive effect on the productivity of HFMD. It is also concluded that the productivity of the HFMD is not significantly affected by increasing the salt concentration when brackish and sea water are used. The productivity also slightly decreases with increasing the salt concentration when extremely saline water is used. The decrement in the productivity reaches 27%, when the salt concentration increases from 40,000 to 130,000 ppm. Based on the conducted economic analysis, the HFMD shows a good potential for desalinating extremely saline water especially when the solar collector is used as a heat source. In this case, the cost per liter of freshwater is reduced by 21.7–23.1% when the evacuated tube solar collectors are used compared to the system using electrical heaters. More reduction in the cost per liter of freshwater is expected when a high capacity solar-powered HFMD plant is installed.

Energy-exergy and environ-economic (4E) analysis of heat storage-based single-slope solar stills integrated with solar air heater.

The energy-exergy and environ-economic (4E) analysis was conducted on a solar still with and without a hybrid thermal energy storage system (TESS) and a solar air heater. The proposed solar still was modified by integrating a rectangular aluminium box filled with paraffin wax and black gravel as the TESS and coupled with a solar air heater. Paraffin wax was selected due to its widespread availability and proven effectiveness in accelerating desalination, improving process uniformity, and maintaining optimal temperature levels. Throughout the experiments, meticulous data on mass loss, air velocity, and temperature were recorded for both conditions. The daily energy efficiency varies from 40.80% to 31.72%, showing a reduction rate with increased water depth. Estimates were made on the average exergy efficiency, losses, outflow, and inflow for the solar still. These were done for both setups. The analysis revealed that CO2 mitigation and credit were more favorable with the TESS. Furthermore, the Energy Payback Time (EPBT) for the hybrid heat storage-based single-slope solar still coupled with a solar air heater is 1.87 years. On the other hand, EPBT values for the hybrid heat storage single-slope solar still and the conventional single-slope solar still were 1.65 years and 0.95 years, respectively. Integrating a thermal energy storage system and solar air heater significantly improved the performance and sustainability of the solar still for desalination, making it a more efficient and environmentally friendly option for freshwater production.

Bioinspired Photo‐Thermal Catalytic System using Covalent Organic Framework‐based Aerogel for Synchronous Seawater Desalination and H2O2 Production

Efficient utilization of solar energy is widely regarded as a crucial solution to addressing the energy crisis and reducing reliance on fossil fuels. Coupling photothermal and photochemical conversion can effectively improve solar energy utilization yet remains challenging. Here, inspired by the photosynthesis system in green plants, we report herein an artificial solar energy converter (ASEC) composed of light‐harvesting units as solar collector and oriented ionic hydrophilic channels as reactors and transporters. Based on such architecture, the obtained ASEC (namely ASEC‐NJFU‐1) can efficiently realize parallel production of freshwater and H2O2 from natural seawater under natural light. The total solar energy conversion (SEC) of ASEC‐NJFU‐1 reaches up to 8047 kJ m‐2 h‐1, corresponding to production rates of freshwater and H2O2 are 3.56 kg m‐2 h‐1 and 19 mM m‐2 h‐1, respectively, which is a record‐high value among all photothermal‐photocatalytic systems reported to date. Mechanism investigation of combining spectrum and experimental studies indicated that the high SEC performance for ASEC‐NJFU‐1 was attributed to the presence of plant bioinspired architecture with carbon nanotubes as solar‐harvestor and COF‐based oriented aerogel as reactors and transporters. Our work thus establishes a novel artificial photosynthesis system for highly efficient solar energy utilization.

Bioinspired Photo-Thermal Catalytic System Using Covalent Organic Framework-Based Aerogel for Synchronous Seawater Desalination and H2O2 Production.

Efficient utilization of solar energy is widely regarded as a crucial solution to addressing the energy crisis and reducing reliance on fossil fuels. Coupling photothermal and photochemical conversion can effectively improve solar energy utilization yet remains challenging. Here, inspired by the photosynthesis system in green plants, we report herein an artificial solar energy converter (ASEC) composed of light-harvesting units as solar collector and oriented ionic hydrophilic channels as reactors and transporters. Based on such architecture, the obtained ASEC (namely ASEC-NJFU-1) can efficiently realize parallel production of freshwater and H2O2 from natural seawater under natural light. The total solar energy conversion (SEC) of ASEC-NJFU-1 reaches up to 8047 kJ m-2 h-1, corresponding to production rates of freshwater and H2O2 are 3.56 kg m-2-1 h-1 and 19 mM m-2 h-1, respectively, which is a record-high value among all photothermal-photocatalytic systems reported to date. Mechanism investigation of combining spectrum and experimental studies indicated that the high SEC performance for ASEC-NJFU-1 was attributed to the presence of plant bioinspired architecture with carbon nanotubes as solar-harvestor and COF-based oriented aerogel as reactors and transporters. Our work thus establishes a novel artificial photosynthesis system for highly efficient solar energy utilization.

Enhancing water productivity of solar still using thermal energy storage material and flat plate solar collector

In this research, the impact of integrating solar still with thermal energy storage material and flat plate solar collector (FPSC) on the freshwater productivity was experimentally investigated. The experiments were conducted on three types of similar-sized solar stills under climate conditions of Saudi Arabia. The first type was a conventional solar still (CSS), without any modifications. The second type was a modified solar still (MSS-1), CSS integrated with natural stones in the still basin. The third type was a modified solar still (MSS-2), CSS integrated with both natural stones and FPSC. Three types of natural stones with same quantity were selected and individually tested in the MSS-1 and MSS-2 simultaneously (each stone type on one day). The corresponding experimental results of MSS-1 showed a 11–32% increase in the daily freshwater yield, compared to CSS, indicating a minimal effect of natural stones utilization on the freshwater productivity. The MSS-2 showed a 155–183% increase in the daily freshwater yield, compared to CSS, indicating a significant effect of basin water heating on the freshwater productivity. The total dissolved solids (TDS) level was measured at 112 ppm, which complies with the permissible limits for drinking water quality standards. The economic analysis revealed that the cost to produce one liter of freshwater is 0.028, 0.022, and 0.027 $ from CSS, MSS-1, and MSS-2, respectively. Additionally, the benefit–cost ratio (BCR) analysis demonstrated the economic feasibility of the constructed solar still, with a BCR value of 2.1.

Preliminary experimental studies on coalescer efficiency for liquid-liquid separation

Abstract The international organizations have identified both water demand and accessibility as critical challenges with both current and future implications for human well-being. In reason of that due to the growing demand, it is essential to advance the technologies used in freshwater production, focusing on sustainability while maintaining operational efficiency. Within the HORIZON 2020 program, it was thought to integrate the desalination processes with Renewable Energy Sources (RES). The desalination process is based on Forward Osmosis (FO), which uses a membrane to split pure water from seawater by exploiting the osmotic pressure difference between the feed solution (i.e., seawater) and the draw solution (i.e., permeate side). For the process to be effective, a low-cost method for regenerating the diluted draw solution is necessary. Hence, a viable alternative is to deploy a thermo-responsive polymeric draw agent that can be regenerated by the heat power rejected from a CO2 power cycle integrated with a Concentrated Solar Power. To perform the separation, a liquid-liquid separator (i.e., coalescer), mostly deployed in the oil and gas sector, is proposed to split the fresh-water from the polymeric draw solution. Hence, the aim of this work is to preliminarily assess the performances of the coalescer, aiming at the formulation of an experimental efficiency expression. Expression that is function of: (1) temperature at which the regeneration is performed, (2) residence time, and (3) draw concentration in the initial solution. The draw agent used in the experimental campaign is the PAGB2000, a thermo-responsive co-polymer that has a Lower Critical Solution Temperature (LCST) above which the fluid splits in two distinct phases: a polymer-rich (more concentrated), and a polymer-poor (more diluted). From the analysis it results that the coalescer performances strongly increase with both temperature and residence time, indeed efficiency achieves values near to 100%. On the other hand, the performances slightly worsen with increasing the initial draw concentration. Eventually, having an efficiency formulation can both help the design process of the desalination plant and provide an understanding on how much this technology can be applied in context far from the ones it was developed for.

Exergoeconomic analysis and machine learning-based optimization for a near-zero CO2 emission multi-generation system with freshwater production

Exergoeconomic analysis and machine learning-based optimization for a near-zero CO2 emission multi-generation system with freshwater production

The place of natural resources in the model of transition to a green economy in Azerbaijan

The article explores the role of natural resources in the model of transition to a green economy in Azerbaijan, emphasizing the importance of rational resource use and the implementation of new technologies. A key component of the green economy index is the “natural resources group” sub-index, which includes 10 sub-indicators: volumes of fresh water, water consumption, oil and gas production, land fund structure, fishing, and forest areas. The author also highlights methodological issues that arise in comparative studies, including the dependence of some indicators' absolute values on the size of the country and geographical location. To provide a more accurate assessment of the state of natural resources, the article uses the volume of renewable freshwater per capita, which better reflects the potential for transitioning to a green economy. In conclusion, the article proposes refined indicators for assessing the “natural resources group” based on more reliable data, such as the share of hydrocarbon revenues in GDP, allowing for a deeper understanding of the impact of natural resources on sustainable development in Azerbaijan.

Probing the water adsorption and stability under steam flow of Zr-based metal-organic frameworks using 91Zr solid-state NMR spectroscopy.

The stability of metal-organic frameworks (MOFs) in the presence of water is crucial for a wide range of applications, including the production of freshwater, desiccation, humidity control, heat pumps/chillers and capture and separation of gases. In particular, their stability under steam flow is essential since most industrial streams contain water vapor. Nevertheless, to the best of our knowledge, the stability under steam flow of Zr-based MOFs, which are among the most widely studied MOFs, has not been investigated so far. We explore it herein for three UiO-like Zr-based MOFs built from the same Zr cluster but distinct organic linkers at temperature ranging from 80 to 200 °C. We demonstrate the possibility of acquiring their 91Zr NMR spectra using high magnetic field (18.8 T) and low temperature (140 K) and of interpreting them by comparing experimental data with NMR parameters calculated by DFT. NMR observation of this challenging isotope combined with more conventional techniques, such as N2 adsorption, X-ray diffraction, IR, and 1H and 13C solid-state NMR spectroscopies, provides information not only on the possible collapse of the MOF framework but also on the adsorption of molecules into the pores. We notably show that UiO-66(Zr) and UiO-66-Fum(Zr) built from terephthalate and fumarate linkers, respectively, are stable over 24 h (and even over 7 days for UiO-66(Zr)) under steam flow at all investigated temperatures, whereas UiO-67-NH2 containing a 2-amino-[1,1'-biphenyl]-4,4'-dicarboxylate linker degrades under steam flow at temperatures ranging from 80 to 150 °C but is preserved at 200 °C. The lower stability of UiO-67-NH2 stems from its larger pores and its weaker Zr-O coordination bonds, whereas its preservation at 200 °C results from a more limited condensation of water in the pores.

A new adsorption desalination-cooling system with four beds and two evaporators to enhance freshwater production

A new adsorption desalination-cooling system with four beds and two evaporators to enhance freshwater production

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.

Optimization Study on the Freshwater Production Ratio from the Freezing and Thawing Process of Saline Water with Varied Qualities

Freezing saline water irrigation is an effective technique for leaching soil salts. However, the coupling effects between initial salinity, sodium adsorption ratio (SAR), and freezing temperature of saline water have not been systematically studied. Therefore, a three-factor and five-level quadratic general rotation combination design was adopted, employing indoor simulated freeze–thaw experiments to investigate the influence of these three factors on the freshwater production ratio. The results indicated the following: (1) Within the range of the set experimental factor levels, the freshwater production ratio after the freezing of saline water ranged from 23.34% to 81.11%. (2) The significant negative effect of the main factor on the freshwater production ratio was descending order: initial salinity > freezing temperature. Although the impact of saline water SAR on the freshwater production ratio is insignificant, the interaction between saline water SAR and the freezing temperature has a highly significant negative effect on the freshwater production ratio. (3) At least 83% of the salt content was leached out in the first 16 h when the ice was thawed at 6 °C. These findings are beneficial for selecting appropriate irrigation times based on irrigation water quality in the actual field application of saline water freezing irrigation, with the aim of more efficiently reducing soil salt content.

Photovoltaic-Driven Battery Deionization System for Efficient and Sustainable Seawater Desalination.

Seawater desalination via electrochemical battery deionization (BDI) has shown significant potential for freshwater production. However, its widespread application has been limited by the high energy costs involved. To facilitate the commercialization of BDI technology, it is crucial to develop innovative integrated BDI systems that utilize sustainable energy sources and assess their practical performance for desalination of natural seawater. In this study, we construct the first photovoltaic-driven battery deionization system, termed PV-BDI, capable of continuously and simultaneously removing multiple ions from natural seawater. The system successfully produced freshwater with a total dissolved solids (TDS) level of 704 mg L-1, meeting the maximum acceptable TDS limits recommended by the World Health Organization (WHO) for drinking water standards, which specify a maximum TDS limit of 1000 mg L-1. The mass-specific energy consumption for salt removal to obtain drinking water from natural seawater via this system has been reduced to 0.036 kW·h kg-1, surpassing the performance of other state-of-the-art PV-driven electrochemical-based desalination technologies such as electrodialysis and capacitive deionization (0.068-2.100 kW·h kg-1). This work presents a pioneering proof-of-concept integrated PV-BDI system and demonstrates its practical performance for desalinating natural seawater, thereby laying the foundation for expanding BDI systems in the near future for environmentally friendly and sustainable industrial-scale seawater desalination.

Polyanionic Electrolyte Ionization Desalination Empowers Continuous Solar Evaporation Performance.

Solar evaporation contributes to sustainable and environmentally friendly production of fresh water from seawater and wastewater. However, poor salt resistance and high degree of corrosion of traditional evaporators in brine make their implementation in real applications scarce. To overcome such deficiency, a polyanionic electrolyte functionalization strategy empowering excellent uniform desalination performance over extended periods of time is exploited. This 3D superhydrophilic graphene oxide solar evaporator design ensures stable water supply by the enhanced self-driving liquid capillarity and absorption at the evaporation interface as well as efficient vapor diffusion. Meanwhile, the polyanionic electrolyte functionalization implemented via layer-by-layer static deposition of polystyrene sodium sulfonate effectively regulates/minimizes the flux of salt ions by exploiting the Donnan equilibrium effect, which eventually hinders local salt crystallization during long-term operation. Stable evaporation rates in line with the literature of up to 1.68kg m-2 h-1 are achieved for up to 10 days in brine (15‰ salinity) and for up to 3 days in seawater from Hangzhou Bay in the East China Sea (9‰ salinity); while, maintaining evaporation efficiencies of ≈90%. This work demonstrates the excellent benefits of polyanionic electrolyte functionalization as salt resistance strategy for the development of high-performance solar powered seawater desalination technology and others.

High-Performance Silicone Sponge Evaporators with Low Thermal Conductivity for Long-Term Solar Interfacial Evaporation and Freshwater Harvesting.

Solar interfacial evaporation (SIE) has emerged as a highly promising approach for sustainable freshwater harvesting. However, maintaining a stable evaporation rate and achieving a high freshwater yield in high-salinity brines remain a significant challenge. In this study, we present the development of silicone sponge-based evaporators with a "free-salt" structure, designed to enhance the efficiency of SIE and freshwater collection. These evaporators, designated as PSS@Fe3O4/CNTs, were fabricated by grafting durable silicone onto a silicone sponge framework, followed by the incorporation of Fe3O4 nanoparticles and carbon nanotubes. The unique combination of exceptional photothermal properties and a controlled yolk-shell structure with low thermal conductivity enabled the PSS@Fe3O4/CNT evaporators to sustain a stable evaporation rate of 1.87 kg m-2 h-1 in real seawater over 200 h of continuous operation under 1 sun illumination. Importantly, no salt accumulation was observed on the evaporator surfaces, even when exposed to highly concentrated brines. In a closed system equipped with a condenser, these evaporators achieved freshwater production rates of 14.5 and 11.8 kg m-2 over 10 h from 10 and 20 wt % NaCl solutions, respectively, under 1 sun illumination. These values correspond to normalized production rates of 1.45 and 1.18 kg m-2 h-1, showcasing the consistent and efficient performance of the evaporators across varying salinity levels. Beyond salt rejection, the PSS@Fe3O4/CNT evaporators also demonstrated the ability to effectively remove various heavy metal ions (e.g., Cu2+ and Zn2+) and organic pollutants from contaminated water. This work provides valuable insights into innovative evaporator designs for efficient freshwater production from seawater and wastewater.