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Freeze desalination of samples of seawater from Umluj beach, Red Sea, in Saudi Arabia, was investigated by laboratory experiments using nondirect freezing. The influence of kinetic parameters including degree of crystallization, freezing–melting cycles, and gradual melting on the total dissolved solids (TDS) and salt rejection was examined. The mel...
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... desalination processes are based on the fact that ice crystals are made up of essentially pure water when the temperature of saline water is lowered to its freezing point and further heat is removed [10]. Typical binary phase diagram of salt water (Fig. 3) shows the temperature-composition fraction of NaCl relationships among the different phases of the salt water. For a binary solution of 4% NaCl, which is the salinity of the seawater samples in this study, water starts to transit from the liquid phase to the solid crys- tal phase when the temperature is decreased and lower than the ...
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... Jayakody et al. [85] used a combination of computational fluid dynamics simulations and experimental verification to demonstrate that gradual freezing and melting operations can reduce the salt content in ice, ultimately achieving desalination. Badawy et al. [86] experimentally examined the effects of crystallinity, the number of freeze-melt cycles, and gradual melting on total dissolved solids and salt removal efficiency, with results presented in Figure 12. After a single freeze-melt cycle, the TDS of the ice water was approximately 18,932 mg/L, significantly lower than the original seawater TDS of 40,916 mg/L. ...
... The influence of experimental parameters on desalination rate: (a) the influenc freezing melting cycles on desalination rate and freshwater loss; (b) melting time parameter; (c influence of freezing melting cycles on desalination rate and freshwater loss; (d) the influen freezing melting cycles on desalination rate and freshwater loss[86]. ...
... The influence of experimental parameters on desalination rate: (a) the influence of freezing melting cycles on desalination rate and freshwater loss; (b) melting time parameter; (c) the influence of freezing melting cycles on desalination rate and freshwater loss; (d) the influence of freezing melting cycles on desalination rate and freshwater loss[86]. ...
As global demand for freshwater grows, seawater desalination has become one of the most promising methods for obtaining freshwater. Many coastal nations have included it in their sustainable development plans and are actively advancing related technologies. Compared with traditional desalination methods, such as distillation and membrane-based desalination, seawater freezing desalination offers the benefit of producing large amounts of freshwater at lower costs. This study provides an overview of the main methods and principles of seawater freezing desalination and summarizes the latest research progress. This paper also discusses experimental and simulation studies of different principles. Current research shows that both direct and indirect seawater freezing desalination technologies have become relatively mature, laying a foundation for practical applications. Hydrate-based desalination, eutectic freezing technology, and vacuum freezing technology offer cost-reduction benefits, but existing technologies have limitations, making these areas hot topics in research. Additionally, this paper discusses the experimental progress and simulation methods associated with this, elaborates upon, and analyzes the freezing crystallization process and desalination efficiency from the perspective of the bottom layer of crystal growth, offering valuable insights for future research. It concludes by summarizing and predicting the development of these technologies, emphasizing their great potential due to their low-cost and sustainable features.
... Various heat sources such as fossil fuels, geothermal energy, solar energy, and nuclear energy can be utilized for this purpose. Examples of thermal methods include multiple-effect distillation, Freezing Desalination [20,21], Adsorption Desalination, Multi-Stage Flash, and Humidification Dehumidification [22]. On the other hand, the membrane method utilizes a membrane to separate seawater or salt water into fresh water. ...
... Thus, the water activity coefficient (α), which is defined as the ratio between the vapor pressure above saline water and that above freshwater at the same temperature, has been introduced to characterize the effect of salinity on saline lake evaporation (Salhotra et al., 1987;. Because saline water drains out salt during freezing (Badawy, 2016), we only introduced the α into the evaporation simulation of Qinghai Lake during IFP. The three models were as follows. ...
... Due to the lack of accurate measurements of deep lake temperatures, energy budget closure ratios of EC observations in QHL are not given in this study. EC measurements have been widely used to quantify the E of several global lakes, including Lake Superior in North America, Great Slave Lake in Canada, Lake Geneva in Switzerland, Lake Valkea-Kotinen in Finland, and Taihu Lake, Erhai Lake, Poyang Lake, Nam Co, Selin Co, and Ngoring Lake in China (Blanken et al., 2000(Blanken et al., , 2011Vercauteren et al., 2009;Nordbo et al., 2011;Wang et al., 2014;Li et al., 2015Li et al., , 2016Liu et al., 2015;Guo et al., 2016; , 2016;. With most of the known energy budget closure ratios over 0.7, EC observations of lakes are regarded as an accurate and reliable direct measurement method of E, even in lakes over the QTP (Wang et al., 2020). ...
Saline lakes on the Qinghai–Tibet Plateau (QTP) affect the regional climate and water cycle through water loss (E, evaporation under ice-free conditions and sublimation under ice-covered conditions). Due to the observational difficulty over lakes, E and its underlying driving forces are seldom studied when targeting saline lakes on the QTP, particularly during ice-covered periods (ICP). In this study, the E of Qinghai Lake (QHL) and its influencing factors during ice-free periods (IFP) and ICP were first quantified based on 6 years of observations. Subsequently, three models were calibrated and compared in simulating E during the IFP and ICP from 2003 to 2017. The annual E sum of QHL is 768.58±28.73 mm, and the E sum during the ICP reaches 175.22±45.98 mm, accounting for 23 % of the annual E sum. E is mainly controlled by the wind speed, vapor pressure difference, and air pressure during the IFP but is driven by the net radiation, the difference between the air and lake surface temperatures, the wind speed, and the ice coverage during the ICP. The mass transfer model simulates lake E well during the IFP, and the model based on energy achieves a good simulation during the ICP. Moreover, wind speed weakening resulted in an 7.56 % decrease in E during the ICP of 2003–2017. Our results highlight the importance of E in ICP, provide new insights into saline lake E in alpine regions, and can be used as a reference to further improve hydrological models of alpine lakes.
... Phase diagram of NaCl-H 2 O highlighting the freezing point depression as NaCl concentration is increased (Retrieved from[21]). ...
Freeze desalination (FD) is an energy-efficient desalination method that shows promise over traditional thermal-based approaches. FD requires minimal energy by utilizing latent heat of fusion during the phase transition of saltwater from liquid to solid state. However, the stochastic nature of nucleation and salt trapping in the formed ice has hindered industrial implementation. This study focuses on experimental investigations of ice nucleation during the freezing of brine droplets. The effects of droplet size (3-9 μL), salinity (0-70 g/L), and freezing temperature (− 15 • C to − 40 • C) on nucleation behavior are examined. Results showed that smaller droplets exhibit faster cooling rates, reduced supercooling degrees (SD) (12.00 to 9.81 • C), and quicker nucleation onset (117.95 to 72.7 s). Higher droplet salinity leads to decreased nucleation temperatures (from − 13.89 to − 15.32 • C) while lower freezing temperatures enhance cooling rates and reduce nucleation times (from 123.6 to 48.2 s). The analytical model has accurately predicted nucleation times and temperature evolution. Simulation results suggest that freezing at extremely low temperatures, i.e., − 40 • C, yields to shorter nucleation time, i.e., 50 s for 5μL brine droplet. Varying initial temperatures (20-50 • C) showed faster precooling but delayed nucleation, while nucleation temperatures remain consistent. These insights contribute to optimizing FD for energy-efficient desalination.
... In thermal processes, the feed water ( [25][26][27]. Beyond the conventional and commercial desalination methods discussed previously, numerous alternative technologies, including Membrane Distillation (MD), are currently under research and development (refer to Fig. 1) [28,29], Humidification Dehumidification (HDH) [30,31], Capacitive Deionization (CDI) [32,33], Forward Osmosis (FO) [34,35], Freezing Desalination (FD) [36,37], Adsorption desalination (AD) [38,39], etc. Compared to thermal processes, membrane desalination processes have several advantages, including lower capital cost and energy consumption, lower footprint, higher recovery ratios, less vulnerability to scaling and corrosion due to ambient-temperature operation, and membrane rejection of microbial contamination [21]. ...
... Providing clean water to everyone in the world is one of the challenges of this century, while the availability of fresh water is only ∼2.50% of the total global water (Soliman et al., 2021), while on the other hand, the amount of seawater is abundant and unlimited. However, seawater cannot be consumed directly by humans because of its very high salinity or salt content of ± 35,000 ppm, while the maximum salt content that humans can consume is 500 ppm (Badawy, 2016). Additional water treatment is needed to reduce the salinity of seawater and make it fit for human consumption. ...
Thin film composite membranes of macroporous nylon substrates, graphene oxide (GO) sheets, and polyvinyl alcohol (PVA) with Zn2+ (c) ions as cross-linkers have been successfully prepared. This study aims to obtain the membrane composition with the highest desalination efficiency and the best membrane permeability and stability. Membrane performance in desalination applications was evaluated by measurement of water flux and salt rejection. GO was successfully synthesized using a modified Hummers method, and the membrane was prepared by vacuum filtration with various volumes of PVAy ( y = 1 mL, 5 mL, and 10 mL). c-GO-PVA membranes were characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), water contact angle, and scanning electron microscopy (SEM). The experimental results show that adding a crosslinker increases the membrane’s stability, and adding PVA increases the hydrophilicity. The desalination test showed that pure GO membrane had high flux but the lowest salt rejection. The c-GO PVA5 nylon membrane has a high water flux of 20.68 kg m−2 h−1 and high salt rejection (close to 100.0%), so it is recommended as a pervaporation membrane.
... At a high ice formation rate, the ice is still heavily contaminated. Hence, for ice with high contamination levels, it is necessary to further improve the ice purity by melting (Badawy, 2016). The ice used in the ice melt experiments was formed by freezing real compressed leachate. ...
A small amount of leachate with complex composition will be produced during the compressing of municipal solid waste in refuse transfer stations. In this study, the freeze-melt method, a green and efficient wastewater treatment technology, was used to treat the compressed leachate. The effects of freezing temperature, freezing duration, and ice melting method on the removal rates of contaminants were investigated. The results showed that the freeze-melt method was not selective for the removal of chemical oxygen demand (COD), total organic carbon (TOC), ammonia-nitrogen (NH3-N) and total phosphorus (TP). The removal rate of contaminants was positively correlated with freezing temperature and negatively correlated with freezing duration, and the slower the growth rate of ice, the higher the purity of ice. When the compressed leachate was frozen at -15 °C for 42 h, the removal rates of COD, TOC, NH3-N and TP were 60.00%, 58.40%, 56.89% and 55.34%, respectively. Contaminants trapped in ice were removed during the melting process, especially in the early stages of melting. The divided melting method was more beneficial than the natural melting method in removing contaminants during the initial stage of melting, which contributes to the reduction of produced water losses. This study provides a new idea for the treatment of small amounts of highly concentrated leachate generated by compression facilities distributed in various corners of the city.
... The crystalized ice is collected, washed, and melted to obtain lower salinity brine for the next round of freeze desalination. As shown in Figs. 5 and 6 , multiple stages of freezing/melting need to be carried out to reach the standard of potable water (1 g/L) according to the experimental work by the authors [44] and Badawy [45] . In the previous work of authors [44] , as shown in Fig. 6 , 35 g/L saline water was desalinated through 6 freezing/melting stages with 60% crystallization fraction at each stage to obtain the portable water (1 g/L) as shown in Fig. 6 . ...
... Finally, the last stage was carried out with 35% crystallization fraction to obtain potable water (1 g/L). Similarly, according to the work by Badawy [45] , 8 stages were used for the desalination of seawater with a salinity of 41 g/L to obtain the portable water (0.61 g/L) with 87% crystallization fraction at each stage. The number of freezing/melting stages depends on the cooling conditions as well as the initial salinity of the brine. ...
Clean, drinkable water is essential for human health and well-being. However, access to clean water is becoming a global problem due to climate change and over exploitation of natural water resources. Desalination is widely accepted as a solution to meet water demands in areas with access to seawater. However, remote areas such as small islands far from the mainland pose a special challenge as they lack the infrastructure to meet electricity and water demands. This paper investigates the deployment of freeze desalination (FD) coupled with thermoacoustic engine and refrigerator (TAE/R) to provide freshwater to small settlements in remote locations like small islands. It presents an economic feasibility assessment of deployment of waste energy to satisfy the freshwater requirements, as an alternative to using conventional techniques such as reverse osmosis (RO) and thermal distillation (TD) that are energy intensive. Different scenarios are presented comparing the economic feasibility of FD vs. RO. The analysis is done based on the net present value (NPV), internal rate of return (IRR), selling price, and payback period using cashflow diagrams. Compared with the RO, FD powered by TAE/R turns out to be the most favorable option to produce freshwater from seawater for a small community on an isolated island due to high NPV and IRR, and low selling price and payback period.
... Crystallization, separation, surface cleaning, and freezing of the crystals are all involved in these processes. Gravity drainage, centrifugal, filtration, and wash columns can all be used to separate ice crystals [15][16][17]. ...
... Previous research has investigated the FM technique using non-direct contact freezing for fluoride removal [32][33][34], seawater desalination [5,17], synthetic brackish and saline water [35], and nitrate removal [36]. These studies concluded that solar-assisted solutions might have a lot of potential in this instance. ...
Although the freezing-melting process is not widely used commercially, perhaps the most significant potential advantage of desalination by freezing is the very low energy required compared with other desalination processes. Five seawater samples of 3,000 mL each were collected from different locations at the Gaza Strip beach. The physicochemical characteristics of the raw seawater samples were tested. The seawater samples were poured into an identical flask connected directly to an external stainless steel single-phase freezer (thermally protected-Sichuan Dandy Co. Ltd. 220 Volt, 50 Hz) with an energy consumption of 0.1 kW/h to be crystallized by direct freezing (at −20°C). Then the physicochemical analysis was undertaken on the water produced from three repeated freezing-melting (FM) cycles for each seawater sample. The average water mineral reduction percentages ranged from 39.0% to 45.5%, (49.7%-52.8%), and (56.0%-59.0%) for the 1st, 2nd, and 3rd FM cycles, respectively. The overall average removal percentage of dissolved minerals and constituents after the 3rd FM cycle for North Gaza, Gaza, Middle area, Khan Younis, and Rafah seawater samples was 84.7%, 85.6%, 87.3%, 86.4%, and 87.6%, respectively. The time of crystallization in the 1st, 2nd, and 3rd freezing cycles was 80, 50, and 30 min, respectively. The consumed energy for produced water after the three cycles of freezing was 0.018, 0.022, 0.018, 0.023, and 0.021 kW/L for the North Gaza, Gaza, Middle Area, Khan Younis, and Rafah seawater samples, respectively. The FM technique could be used as a pretreatment method for other methods of desalination.
... Therefore, different process designs have been adapted to reach a lower water salinity. Badawy [13] experimented with different F/M cycles, crystallization degrees, and gradual melting. The authors of [14] conducted the process by modifying the stirring speed, freezing time, and subcooling. ...
Given the high human demand for freshwater and its consequent scarcity, desalination processing seems to be a key solution, given the vast amount of seawater on the planet. Currently, desalination plants provide about 95 million m3/day freshwater in 177 countries worldwide. However, desalination is an energy-intensive, demanding technique that generally uses fossil fuels and contributes to global warming via greenhouse gas emissions. Freezing/melting desalination (F/M) uses about 70% less thermal energy than the boiling process. Unfortunately, this technique is rarely used, mainly because of salt separation problems at low temperatures close to 0 °C. Most models have determined their results assuming a saline concentration value of the retained liquid; however, there is a significant disagreement in this value. This study proposes a unidimensional model based on thermal and mass diffusion evolution. The model predicts the successful separation of salt-free ice to avoid salt diffusion before encapsulation; the process depends on temperature, saline gradients, and time. The calculations in this paper are based on the salt concentration in the liquid-solid interface, which has been extensively studied, achieving an accurate performance of the proposed model.
