Desalination Research Articles

Thermodynamic properties of lower critical solution temperature (LCST) mixtures for application in energy-water systems.

Mixtures that possess a lower critical solution temperature (LCST) phase behavior are homogeneous at temperatures below the LCST and separate into two phases above the LCST. These materials have recently received interest for use in various applications, including refrigeration, dehumidification, desalination, and atmospheric water harvesting. However, proof-of-concept demonstrations of cycles employing these materials have shown poor performance, due to the thermodynamic properties of existing LCST mixtures. This work develops a theoretical framework to evaluate the thermodynamic properties (chemical potential, partial molar enthalpy, and partial molar entropy) required for a mixture to exhibit LCST behavior and meet the application-specific property targets. Our analysis reveals that a hypothetical LCST mixture that would outperform existing ones would need a more negative partial molar enthalpy (to achieve lower chemical potentials), but it would also need a more negative partial molar entropy (to preserve LCST behavior). Specifically, LCST refrigeration and dehumidification would require a partial molar enthalpy and entropy of water that are an order of magnitude greater than existing LCST mixtures, while LCST-based desalination requires properties 2.5× greater than existing mixtures. We show that improved LCST mixtures with lower chemical potentials would necessarily need more heat to induce phase separation, and we derive an expression to predict the enthalpy of separation using water activity data. Finally, we demonstrate that the addition of a hygroscopic additive (e.g., LiCl) to an LCST mixture does not increase the chemical potential difference between the two phases. Overall, this work lays out the thermodynamic framework and target properties that new LCST mixtures must possess and discusses implications for system performance.

Synergistic optimization of membrane distillation-reverse electrodialysis for sustainable desalination and salinity gradient power generation

Synergistic optimization of membrane distillation-reverse electrodialysis for sustainable desalination and salinity gradient power generation

Techno-economic assessment of distributed wellhead RO water treatment for nitrate removal and salinity reduction: A field study in small disadvantaged communities.

Techno-economic assessment of distributed wellhead RO water treatment for nitrate removal and salinity reduction: A field study in small disadvantaged communities.

Advanced Multi-functional polyurethane sponge with excellent salt Resistant, Antifouling and Oil-Water separation capabilities for highly efficient and Persistent solar desalination

Advanced Multi-functional polyurethane sponge with excellent salt Resistant, Antifouling and Oil-Water separation capabilities for highly efficient and Persistent solar desalination

Harnessing halophytes to mitigate the environmental impact of membrane desalination brine.

Harnessing halophytes to mitigate the environmental impact of membrane desalination brine.

Highly efficient solar water desalination systems based on plasmonic Ni nanoparticles embedded in mesoporous TiO2 scaffold as the photothermal material

Highly efficient solar water desalination systems based on plasmonic Ni nanoparticles embedded in mesoporous TiO2 scaffold as the photothermal material

A novel and sustainable invasive plant wood-based solar interfacial evaporator for efficient brackish water desalination

A novel and sustainable invasive plant wood-based solar interfacial evaporator for efficient brackish water desalination

Polystyrene waste-derived ion-exchange resins for water desalination

Polystyrene waste-derived ion-exchange resins for water desalination

Efficient high-rate brackish water desalination via solid-electrolyte-assisted flow-electrode capacitive deionization

Efficient high-rate brackish water desalination via solid-electrolyte-assisted flow-electrode capacitive deionization

Incorporation of transition metal-oxide on 3D porous carbon network for electrochemical water desalination and heavy-metals removal.

Incorporation of transition metal-oxide on 3D porous carbon network for electrochemical water desalination and heavy-metals removal.

Multifunctional carbon nanotubes based hydrogel integrates photothermal water desalination, photothermal power generation, sensing, and flame retardancy, with a multi purpose and adjustable thermoelectric effect.

Multifunctional carbon nanotubes based hydrogel integrates photothermal water desalination, photothermal power generation, sensing, and flame retardancy, with a multi purpose and adjustable thermoelectric effect.

Impact of surfactant modified-MoS2 induced defects on the performance of thin-film nanocomposite (TFN) membranes: Application in brackish water desalination

Impact of surfactant modified-MoS2 induced defects on the performance of thin-film nanocomposite (TFN) membranes: Application in brackish water desalination

Zwitterion functionalized graphene oxide thin film nanocomposite membrane for brackish water desalination and natural organic matter removal

Zwitterion functionalized graphene oxide thin film nanocomposite membrane for brackish water desalination and natural organic matter removal

High-performance 3D Hydrogels-based evaporator with multidirectional hierarchical pore structure for efficient salt-resistance in continuous water desalination

High-performance 3D Hydrogels-based evaporator with multidirectional hierarchical pore structure for efficient salt-resistance in continuous water desalination

Air-cathode desalination cells for simultaneous wastewater treatment, brackish water desalination, and power generation

Air-cathode desalination cells for simultaneous wastewater treatment, brackish water desalination, and power generation

Thermodynamic and economic analysis of a novel solar-driven integrated cooling, heating, power, and desalination unit for vertical farming system

Thermodynamic and economic analysis of a novel solar-driven integrated cooling, heating, power, and desalination unit for vertical farming system

Thermodynamic and Thermoeconomic Analysis of a Multigeneration System Based on Solar Energy Using Nanofluid for Power, Fresh Water, Hydrogen, Heating and Cooling Production

In this study, the thermodynamic and thermoeconomic analysis of a multigeneration system which produces power, cooling, domestic heating, hydrogen and freshwater has been carried out. The main source of energy for this system is a solar parabolic trough collector (PTC). The working fluid applied for this solar collector is Al2O3-Therminol VP1 nanofluid. The subsystems of this multigeneration system are a steam Rankine cycle for power production, an organic Rankine cycle for power production, a double-effect absorption refrigeration system for cooling production, a domestic water heater for hot water production, a PEM electrolyzer for hydrogen production and a RO desalination unit for freshwater production. In the ORC cycle a TEG unit is applied instead of the condenser for extra power production. The system is analyzed by using the EES software. The effects of different parameters as well as the effects of nanoparticles on the performance of the proposed system were investigated. According to the results, the energy and exergy efficiency of the system are 33.81 % and 23.59 %, respectively. Among the studied working fluids in the ORC cycle, n-pentane shows the best performance. The energy and exergy efficiency of the system increases by the nanoparticle volume concentration and the solar radiation increase. Moreover, the collector inlet temperature has a negative effect on the hydrogen and freshwater production rates. Finally, it is proved that the PTC collector has the highest amount of exergy destruction rate in the studied system.

Membrane-Based Processes for Water Treatment and Desalination: A Comprehensive Review

Membrane-Based Processes for Water Treatment and Desalination: A Comprehensive Review

Evaluation of the efficiency of the processing of sodium chloride solutions by electrodialysis in a three-chamber electrolyzer using a high-basic anionite

The desalination process of highly mineralized waters is a rather multifactorial process that depends on a number of technical, economic and environmental aspects. This is an important stage for obtaining fresh water for its further use in various areas: from drinking water supply to industry. Processing of reverse osmosis water desalination concentrates is a relevant area of research not only in terms of waste disposal, but also in the development of low-waste resource-efficient production, which requires the implementation of innovative solutions and obtaining secondary useful products. One of the promising approaches to the implementation of processes for processing sodium chloride solutions is the use of electrochemical methods of chloride oxidation to obtain sodium hypochlorite and other products of oxidized chlorine - effective reagents for water disinfection, bleaching of fibrous materials, disinfection of various environments. The aim of the article is to study the processes of electrochemical processing of sodium chloride solutions - waste from the processes of desalination of water containing chlorides in three-chamber electrolyzers with the production of oxidized chlorine compounds and alkali solutions, determining the efficiency of capturing active chlorine in the anode chamber using a highly basic anion exchanger. To achieve the set goal, the following tasks were solved: - The parameters of the process of effective purification of solutions from sodium chloride in the working chamber of a three-chamber electrolyzer were determined depending on the concentration of sodium chloride and the anode density of the steam. - The efficiency of capturing active chlorine in the anode region by a highly basic anion exchanger was studied depending on the parameters of the electrolysis process. The processes of processing sodium chloride solutions, close in composition to the concentrates of reverse osmosis water desalination by electrodialysis in a three-chamber electrolyzer using a cationic membrane MA-40 and anionic membrane MA-41, were studied. The cathode chamber is filled with an alkali solution with a concentration of 50 mg-eq/dm3, the anode chamber is filled with a sodium chloride solution and highly basic anion exchanger AB-17-8, the working chamber is filled with a sodium chloride solution. During electrolysis, alkalinity was determined at equal intervals in the cathode region; in the working chamber, the concentration of chlorides and alkalinity or acidity; in the anode chamber, the concentration of chlorides, active chlorine, and acidity were determined. Also, during the electrolysis process, the exchange capacity of the anion exchanger for active chlorine was determined. For this, a certain volume of the anion exchanger was placed in a flask and filled with a sodium sulfite solution of a certain concentration. The flask was hermetically sealed and left for a day. The next day, the residual amount of active in the solution was determined by the iodometric method. It has been shown that the efficiency of chloride oxidation increases with increasing their concentration and increasing the electrolysis time. The electrolysis process proceeds with the formation of active chlorine and hypochlorite. In addition to these substances, the formation of chlorite, chlorate and chlorine dioxide is possible. Degassing of active chlorine and chlorine dioxide leads to significant losses of oxidized chlorine compounds and to a decrease in the current yield of these products. The process is accompanied by significant acidification of the anolyte, which contributes to the acceleration of degassing of active chlorine, a decrease in its current yield, and a decrease in the intensity of chloride diffusion from the working chamber to the anode zone. The use of a highly basic anion exchanger that adsorbs hypochlorite anions, as well as, in the case of formation, chlorite and chlorate anions, contributes to the reduction of losses of oxidized chlorine compounds.

Desalination of Hyper-Concentrated Brines via Microwave Irradiation Mechanism: Case Studies. A Simultaneous Integration of Thermal Desalination, Steam Turbines, and Brine Mining into a Desalination Plant Design

A new and novel approach to thermal desalination is being developed