Salt Diffusion Research Articles

Revisiting Gradient Layer Heat Extraction in Solar Ponds Through a Realistic Approach

Abstract In this paper, the concept of heat extraction from the gradient zone (GZ) in solar ponds has been analyzed in a more realistic manner to overcome the drawbacks of previously conducted studies. For this purpose, a net heat transfer coefficient has been invoked to investigate the heat transfer occurring from the GZ to the exchanger installed in this zone, in addition to the storage zone (SZ). Analytical solutions for temperature profiles in the GZ and the corresponding exchanger have been obtained which are further used to investigate various aspects of the thermal performance of the pond. The consideration of realistic heat transfer across the GZ exchanger reveals that the ideal thickness of GZ yielding maximum power output is always under-predicted by the idealized assumption of the literature. Unlike intuitive perception, the conventional assumption of an infinite heat transfer coefficient does not affect the pond stability because, for all practical purposes, the critical salt diffusion rate predicted by it is always larger than the actual critical value required for ensuring stable pond operation. However, as expected, the rate of exergy destruction caused by the pond’s operation is found to be underestimated by the idealized assumption. This study provides a useful analytical tool to make more realistic predictions on various performance parameters of solar ponds utilizing the heat stored in their GZ.

Numerical modeling of methane hydrate accumulation with mixed sources in marine sediments: Case study of Shenhu Area, South China Sea

The natural gas hydrates detected in Shenhu Area, South China Sea are considered to have great potential for exploitation and to become a research hotspot. However, details of the dynamic accumulation and evolution processes of gas hydrate over a long time in this area remain unclear. In this study, we developed a numerical model to predict the accumulation of gas hydrates in the marine sediments by introducing the biogenic methanogenesis module to the framework of the existing simulator TOUGH+HYDRATE. A one-dimensional dynamic model was applied to reproduce the formation of gas hydrate at site SH2 in Shenhu Area. The burial of sediments and associated phenomena (e.g., evolution of temperature, sediment compaction and consequent reduction in sediment porosity and permeability, fluid expulsion) are taken into account. Modeling results indicate that with the conventional conversion coefficient (CC) of organic carbon to methane of 0.15, the amount of in-situ biogenic methane is not sufficient to form the highly saturated hydrate detected at this location and the remaining methane (91.4%) is supplied by the upward flow of fluids. The tectonic movement that took place about 1.5 Ma created pathways for the fluids to migrate vertically. The pore water and methane gas fluxes in the upward fluids were determined as 2 × 10−10 kg/s·m2 and 1 × 10−11 kg/s·m2, respectively, using the proved hydrate saturation profile and measured pore water chlorinity from recovered core samples. The distribution of hydrate in the sediments is significantly influenced by pore water salinity. The inhibitory effect of salt on hydrate formation, which shifts the pressure of three-phase (i.e., solid hydrate, methane gas and pore water) equilibrium to actual pore water pressure, could be the major reason for the appearance of a three-phase co-existence zone in the hydrate concentrated zone. Additionally, the water flux and diffusivity of salt have a profound effect on the formation of gas hydrate by affecting the salinity of pore water in the gas hydrate concentrated zone. The results of this study are of great significance for guiding marine gas hydrate exploration and resource evaluation.

Measurement of Three Transport Coefficients and the Thermodynamic Factor in Block Copolymer Electrolytes with Different Morphologies.

The design and engineering of composite materials is one strategy to satisfy the materials needs of systems with multiple orthogonal property requirements. In the case of rechargeable batteries with lithium metal anodes, the system requires a separator with fast lithium ion transport and good mechanical strength. In this work, we focus on the system polystyrene-block-poly(ethylene oxide) (SEO) with bis(trifluoromethane)sulfonimide lithium salt (LiTFSI). Ion transport occurs in the salt-containing poly(ethylene oxide)-rich domains. Mechanical rigidity arises due to the glassy nature of polystyrene (PS). If we assume that the salt does not interact with the PS-rich domains, we can describe ion transport in the electrolyte by three transport parameters (ionic conductivity, κ, salt diffusion coefficient, D, and cation transference number, t+0) and a thermodynamic factor, Tf. By systematically varying the volume fraction of the conducting phase, ϕc between 0.29 and 1.0, and chain length, N between 80 and 8000, we elucidate the role of morphology on ion transport. We find that κ is the strongest function of morphology, varying by three full orders of magnitude, while D is a weaker function of morphology. To calculate t+0 and Tf, we measure the current fraction, ρ+, and the open circuit potential, U, of concentration cells. We find that ρ+ and U follow universal trends as a function of salt concentration, regardless of chain length, morphology, or ϕc, allowing us to calculate t+0 for any SEO/LiTFSI or PEO/LiTFSI mixture when κ and D are known. The framework developed in this paper enables predicting the performance of any block copolymer electrolyte in a rechargeable battery.

Optimizing the monomer structure of polyhedral oligomeric silsesquioxane for ion transport in hybrid organic–inorganic block copolymers

ABSTRACTPoly(ethylene oxide)‐b‐polyhedral oligomeric silsesquioxane (PEO–POSS) mixed with lithium bis(trifluoromethanesulfonyl)imide salt is a nanostructured hybrid organic–inorganic block copolymer electrolyte that may enable lithium metal batteries. The synthesis and characteristics of three PEO–POSS block copolymer electrolytes which only differ by their POSS silica cage substituents (ethyl, isobutyl, and isooctyl) is reported. Changing the POSS monomer structure results in differences in both thermodynamics and ion transport. All three neat polymers exhibit lamellar morphologies. Adding salt results in the formation of a disordered window which closes and gives way to lamellae at higher salt concentrations. The width of disordered window decreases with increasing length of the POSS alkyl chain substituent from ethyl to isobutyl and is absent in the isooctyl sample. Rheological measurements demonstrate good mechanical rigidity when compared with similar all‐organic block copolymers. While salt diffusion coefficient and current ratio are unaffected by substituent length, ionic conductivity increases as the length of the alkyl chain substituent decreases: the ethyl substituent is optimal for ion transport. This is surprising because conventional wisdom suggests that ion transport occurs primarily in the PEO‐rich domains, that is, ion transport should be unaffected by substituent length after accounting for the minor change in conducting phase volume fraction. © 2020 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2020 © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 363–371

Cover Feature: Dynamic Ion Correlations in Solid and Liquid Electrolytes: How Do They Affect Charge and Mass Transport? (ChemElectroChem 2/2020)

The Cover Feature illustrates the types of ion correlations that are found in solid and liquid electrolytes used in lithium-based batteries. The effect of such correlations on the overall mass and change transport, e.g. the salt diffusion coefficient and the transference number of lithium, can be described by combining linear response theory and Onsager′s linear irreversible thermodynamics. In this Review, the theoretical foundation for ionic correlations in solid and liquid electrolytes is presented and applied to recent literature reports. More information can be found in the Review by N. M. Vargas-Barbosa and B. Roling on page 367 in Issue 2, 2020 (DOI: 10.1002/celc.201901627).

Electro-osmotic thermal process model for performance enhancement of forward osmosis integrated with membrane distillation

An electroosmotic membrane bioreactor (eOMBR) is employed as the feed side of a forward osmosis (FO) unit for municipal wastewater treatment. Freshwater is drawn osmotically from the feed side to the draw side by desalination brine. The diluted brine is regenerated thermally by direct contact membrane distillation (DCMD). The combined eOMBR-DCMD process, referred to as electro-osmotic thermal process (eOTP), is modeled and its performance is assessed in terms of performance indicators including osmotic water permeation (Jw), reverse salt diffusion flux (Js), and internal concentration polarization parameter (JICP). These indicators depend on operating factors such as draw inlet concentration (cd), sludge retention time in eOMBR (SRT), diffusion coefficient in draw side (Kd), draw inlet flow rate (Qd), and ICP coefficient (KICP). eOTP performance is evaluated in terms of how electric field influences the relationship between the indicators and operating factors. cd and KICP are the most influential factors. Electric field improves the beneficial effect of cd on Jw and reduces the adverse effect of KICP on Jw. Electric field also reduces the adverse effect of cd on JICP but worsens the adverse effect of KICP on JICP. Electric field does not influence the sensitivity of Js to changes in KICP. Lower current density levels improve eOTP performance. The water productivity of eOTP is also improved by higher temperature levels at the draw side when the current density is 5 A/m2. The cost of fresh water production by eOTP was estimated to be $1.90 per m3. This theoretical assessment shows that electro-thermal effects provide a potential for wastewater and brine reuse.

Salt transport in polymeric pervaporation membrane

Abstract The salt transport in a PEBA membrane used in pervaporative desalination was studied. The concentration profile of salt in the membrane during pervaporation was investigated experimentally using a multilayer membrane. The salt was found to be sorbed in the membrane but was not removed during the pervaporative desalination process, and the salt concentration in the membrane varied linearly with position. High purity water was obtained as the permeate as long as the permeate side was kept dry under vacuum. The accumulated salt uptake in the membrane follows the order of MgCl2 > NaCl > Na2SO4. The solubility of salt in the membrane follows the order of MgCl2 > NaCl > Na2SO4. Both the permeability and diffusivity of salt in the membrane follow the order of NaCl > MgCl2 > Na2SO4. The permeability of salt in the membrane is not influenced by the feed salt concentration. It is mainly determined by the diffusion coefficients.

Visualization of the Self-Motion of a Free Wedge of Neutral Buoyancy in a Tank Filled with a Continuously Stratified Fluid and Calculation of Perturbations of the Fields of Physical Quantities Putting the Body in Motion

Based on the results of the space-time analysis of the equations of motion, a technique for visualizing the flow caused by the diffusion of NaCl salt near a horizontal wedge in a fluid continuously stratified in salinity is developed. A laboratory setup is created in which diffusion-induced flows on bodies of neutral buoyancy and self-motion of a horizontal wedge are visualized using various optical methods. Shadowgrams of a free self-moving wedge placed on a neutral buoyancy horizon in a continuously stratified salt solution are compared with the results of calculations.

Dynamic Ion Correlations in Solid and Liquid Electrolytes: How Do They Affect Charge and Mass Transport?

AbstractSolid and liquid electrolytes for electrochemical energy storage and conversion cells, such as batteries, supercapacitors and fuel cells, contain often high concentrations of mobile ions. Therefore, the ion dynamics in these electrolytes is characterized by pronounced directional correlations between successive ion movements, which exert a strong influence on charge and mass transport. In this manuscript, we review the relevant transport properties of (i) single‐ion conducting solid electrolytes and of (ii) liquid electrolytes with a single type of cations and a single type of anions. All transport quantities are based on Onsager's linear irreversible thermodynamics and are defined in the laboratory frame of reference, so that they can be easily related to correlations functions of the equilibrium ion dynamics by means of linear response theory. In the case of single‐cation conducting solid electrolytes, we discuss how the complex interplay between cation‐cation and cation‐lattice interactions leads to a competition between cation self‐correlations and distinct‐cation correlations. In the case of liquid electrolytes, we describe how cation‐cation, anion‐anion, and cation‐anions correlations influence the various transport quantities, such as total ionic conductivity, Haven ratio, salt diffusion coefficient and cation transference numbers. Moreover, we discuss how, in dilute liquid electrolytes, ion correlations can be governed by ion pair formation. Finally, the competition between cation/anion and cation/polymer chain interactions can lead to negative cation transference numbers in polymer electrolytes, i. e. to cations migrating towards the positive electrode. Taken together, these case studies showcase how ion correlations in electrolyte systems can strongly influence the overall efficiency of energy storage and conversion devices due to transport limitations.

On the understanding and feasibility of \u201cBreakthrough\u201d Osmosis

Osmosis is the movement of solvent across a permselective membrane induced by a solute-concentration gradient. Now in ‘Forward Osmosis’ it is empirically observed that the diffusion of the solute is counter to that of the solvent i.e. there is so-called “reverse salt diffusion”. However it has been recently suggested, in a theoretical paper, that if allowance is made for minor deviations from ideal semi-permeability then operation in an overlooked mode of “breakthrough” osmosis would be possible and importantly it would yield relatively large rates of osmosis. A consequential prediction was that in “breakthrough mode”, Pressure-Retarded Osmosis (PRO) would generate very high power densities exceeding those in the conventional mode by one order of magnitude. The practicality of this suggestion was explored and necessarily questions were then raised regarding the foundation of the Spiegler-Kedem-Katchalsky model.Arising from: Yaroshchuk, A., Sci. Rep. 7, 45168 (2017); https://doi.org/10.1038/srep45168

Research on the distribution of soil water, heat, salt and their response mechanisms under freezing conditions

In seasonally frozen soil compartments, freezing affects hydrothermal cycles and solute transport. In order to effectively identify the variation characteristics of soil temperature, moisture and salinity during freezing and the interaction among them, a laboratory unidirectional freezing experiment was set up. During the experiment, three initial gravimetric moisture contents (N1, 18.84 %; N2, 23.43 %; N3, 28.78 %), three freezing temperatures (N4, −5°C; N5, −10°C; N6, −15°C), and three soil bulk densities (N2, 1.33 g⋅cm−3; N5, 1.45 g⋅cm−3; N7, 1.58 g⋅cm−3) were established. The spatial distribution characteristics of the temperature, moisture and salinity in the soil columns were analysed, on the basis of these results, soil water, heat, and salt response relationship functions were constructed by using three indicators, i.e., the soil temperature difference, water flux and salt flux. The study results indicated that as the moisture content increased, the water migration ability increased. In addition, as the freezing temperature decreased and the soil bulk density increased, the rapid freezing of soil inhibited water migration. Furthermore, the movement of water carried a certain amount of salt, and in the soil columns with freezing temperatures of -10 and -15°C, the total soil salt migration decreased by 10.05 and 16.41 mg·cm-2, respectively, compared with the soil column with a freezing temperature of -5°C. The response relationship among the soil water, heat, and salt improved with an increase in the soil moisture content, weakened with a decrease in the freezing temperature and an increase in the soil bulk density, simultaneously, the RMSE between the simulated and measured values of the soil water, heat, and salt response function reduced. In addition, at the spatial scale, the response relationship among soil water, heat, and salt was most significant at the critical soil freezing depth. These study results elucidate the migration and diffusion of soil water, heat, and salt in cold regions and their associated interaction mechanisms, thereby providing guidance for scientific and effective measures for soil improvement, improving the soil ecological environment and ensuring stable increases in grain production.

The Southern Caribbean upwelling system off Colombia: Water masses and mixing processes

The upwelling system off the southern Caribbean coast is probably the main source of the nutrients that support biological productivity in the oligotrophic Caribbean Sea. Subtropical underwater (SUW) that forms the subsurface salinity maximum in the Caribbean Sea is the main source of upwelled waters in this system. Profiles of salinity and temperature with depth derived from four oceanographic cruises and Argo floats showed that upwelled waters have a salinity that is ~0.11 g kg−1 lower than the SUW in the central Caribbean Sea and a seasonal variation of approximately 0.09 g kg−1 that reflects the rainy/dry seasons. In addition, the SUW is ~50 m shallower on the continental shelf slope (~100 m) compared to the depth of the SUW in the central Caribbean Sea. The origin of these modified SUW was analyzed using the Mercator numerical model, which reproduces the main vertical characteristics of the subsurface salinity maximum. The modeled data showed that SUW upwelling off of the La Guajira Peninsula and Venezuela arrive into the system via an intense Caribbean Coastal Undercurrent (CaCU, mean speed ~0.28 m s−1). This current is formed in front of the Nicaragua platform from the divergence of subsurface water flow at the salinity maximum depth. The lower salinity observed in the upwelled waters may be the result of intense vertical mixing processes that could occur when the SUW are transported by the CaCU below the Panama-Colombia Gyre (PCG) region before reaching the upwelling zones. The mixing processes—involving double diffusion and mechanical turbulence driven by vertical shear of horizontal currents—were analyzed using the Turner Angle and the Thorpe scale, respectively. Below a depth of 200 m, double diffusion by salt fingers (diffusivities > 5 x 10−5 m2 s−1) was the main process of salt diffusion, generating a downward salt flux of >2 x 10−2 g kg−1 m d−1 between the SUW and the North Atlantic Central Waters (NACW). Above a depth of 100 m, mechanical turbulent diffusion generates a salt flux towards the surface ranging 0.5–4 x 10−2 g kg−1 m d−1, where double diffusion by salt finger is not possible. The diluted SUW is subsequently transported by the CaCU, connecting—at the subsurface level—the PCG region with the upwelling zones off of Colombia and Venezuela. As well as modifying the salt content of the coastal SUW, these mixing processes may also alter the nutrient content of upwelling waters, the ecosystem effects of which are still unknown.

Revision of the cold processing phases to obtain a targeted salt reduction in typical Italian dry-cured ham

The objective of the study was to reduce the salt content of typical Italian dry-cured ham by at least 25%, to meet the “reduced salt” claim. Salt reduction needs process adjustments to maintain product safety and quality in the absence of nitrites. A way was to reduce the salt input and to shorten the salting period compared to the conventional process. The cold drying period of reduced salt (RS) hams was extended, to decrease aw below 0.97 in inner parts and obtain the same safety conditions of control hams (CS). In RS dry-cured hams the salt reduction was accomplished, the generation of biogenic amines was lower than the threshold values generating toxic effects, and color was the same as in the CS ones. However, in RS proteolysis increased, contributing to texture softening. A strengthened salt diffusion from backside rind could contribute to counteract the rise in proteolysis of biceps femoris muscle, depleted of salt during the process of RS hams.

Structure and diffusion of molten alkali carbonate salts at the liquid-vacuum interface

The liquid-vacuum interface of molten alkali carbonate salts is studied with molecular dynamics simulations. Three salts comprised of LixNayKzCO3 near their respective eutectic concentrations are considered to understand the distribution of ions relative to a liquid-vacuum interface and their diffusivity. These simulations show that each of the cations accumulate at the interface preferentially compared to carbonate. The cation ordering is found to inversely correspond to cation radius, with K being the most likely occupant at the surface, followed by Na, Li, and then the anion. Similar to other studies, the carbonate is found to diffuse more slowly than the cations, but we do observe small differences in diffusion between compositions that present opportunities to optimize ion transport. These results hold consequences for our understanding of ion behavior in molten carbonate salts and the performance of devices employ these electrolytes.

The application of pulsed electric field as a sodium reducing strategy for meat products

This study investigated the potential of pulsed electric field (PEF) as a sodium-reduction strategy for processed meat. Beef jerky was used as a model and prepared using different levels of NaCl, viz. 2.0% (control), 1.2% (T1) and 1.2% along with PEF processing (T2). A significant (p < 0.05) effect of PEF was observed on shear force (N) and toughness (N/mm s) of the products, which was also reflected in sensory scores. No effects for PEF were observed on colour, yield (%) and oxidative and microbial stability. PEF-treated samples (T2) had significantly (p < 0.05) lower sodium content than the control, however, the sensory scores were comparable (p > 0.05) with control and >84% of the panellists preferred T2 samples over T1 for saltiness. Results suggest that PEF treatment improved saltiness by influencing the salt diffusion and sodium delivery that led to better perception during chewing. PEF could be a novel method to produce healthier reduced-sodium meat products.

Determination of Transference Number and Thermodynamic Factor By Use of Anion-Exchange Concentration Cells and Concentration Cells

A method is described for the measurement of lithium ion transference number and thermodynamic factor of a binary electrolyte by the combined use of anion-exchange concentration cell measurements and concentration cell measurements. The measurements were carried out using cells consisting of LiTFSI salt, a poly(ethylene oxide) solvent, a polydiallyldimethylammonium bis(trifluoromethanesulfonyl)imide anion-exchange layer, and lithium foil electrodes. The transference number and thermodynamic factor were fit using expansions suggested by electrolyte theory. The thermodynamic factor was measured to lie within the range of 0.3 to 6 at 80 °C. The lithium ion transference number was measured to be 0.18 at infinite dilution and decrease with increasing concentration. Under ideal operation, the anion-exchange concentration cell directly measures the difference in the chemical potential of salt at two different concentrations. The accuracy of the approximation of ideal operation was estimated, showing that the method is more accurate when the salt has low partitioning into the anion-exchange layer and when the salt diffusivity in the anion-exchange layer is lower than in the solvent. Figure 1

Lithium-Ion Transport and Cycling Characteristics of Fluorinated Electrolytes

Electrical energy is ubiquitous in the modern world, and in order to continue pushing boundaries on consumer wearables, electric vehicles, and grid storage, secondary lithium-based rechargeable batteries need to be enhanced. The performance of binary electrolytes is governed by the electrolyte thermodynamic factor and three transport properties: conductivity, salt diffusion coefficient, and transference number. Rigorous methods for measuring conductivity and the salt diffusion coefficient are well established in literature. NMR and the steady-state current method are often used to measure the transference number, but are predicated on the dilute solution assumption and do not fully consider the non-ideality of the electrolyte. Within this work, we elucidate a complete set of lithium-ion transport properties for mixtures of dimethyl carbonate terminated perfluorinated tetraethylene ether and lithium bis(fluorosulfonyl)imide (LiFSI). The steady-state current transference number is positive across all concentrations and decreases with salt concentration, while the NMR transference number is approximately 0.5 everywhere. In contrast, we find that the transference number using Newman’s concentrated solution theory is negative across all concentrations. We show that Newman’s concentrated solution theory allows for accurate potential and limiting current modeling of lithium half cells whereas the steady-state current transference number severely over-estimates the electrolyte’s limiting current. The disparity between the dilute solution theory measurements and that of Newman’s concentrated solution theory approach indicates the dominance of ion clustering. Figure 1

(Invited) Predicting the Performance of Lithium Metal Electrodes Stabilized By Polymer Electrolytes

It is now commonplace to report the data obtained during cycling of symmetric lithium-electrolyte-lithium cells with solid polymer electrolytes. The parameter that is usually the focus is the number of cycles prior to cell failure. Quantitative prediction of cell failure is a daunting task. As a step toward that aim, we seek to predict the potential needed to cycle such cells at a function of the applied current density. We show that such predictions cannot be made on the basis of conductivity alone. The importance of complete characterization of polymer electrolytes will be discussed. This includes determination of the thermodynamic factor, salt diffusion coefficient and transference number using Newman’s concentrated solution theory. The connection between these parameters and dendrite growth is being explored. If new results are obtained, I will present them at the meeting.

Measurements of Transport Properties of Lithium Salt in Block Copolymer Electrolyte

High charging rate of batteries is an important technical challenge to improve performance of electric vehicles. The battery charging is a function of the redox reactions at the electrode surfaces and transport of ions in the electrolyte. Limiting current density in a battery, the maximum current density at steady state, determines the charging rate. It is a function of the transference number and the diffusion coefficient. The measurement of the transference number and the diffusion coefficient of solid electrolytes has been restricted because of the complexity of experiments. Pulsed-field gradient nuclear magnetic resonance is a powerful method to measure the self-diffusion coefficients of the ions, which can be used to calculate the salt diffusion coefficient and the transference number, but it is only valid for dilute solutions.1, 2 Accurate measurement of the transport parameters for concentrated electrolyte has been conducted combining restricted diffusion, concentration cell and constant current experiments.3 The limitations of this approach are inherently large error from the independent measurements and long experiment time. In this study, the diffusion coefficient and transference number of lithium salt in polystyrene-poly(ethylene oxide) (SEO) electrolyte has been measured by spectroscopic and electrochemical methods with a simple experimental setup. A one-dimensional numerical diffusion model was used to determine the salt diffusion coefficient as a function of concentration. A non-monotonic concentration dependence was observed, initially decreasing with increasing salt concentration, then increasing after a minimum at 1.3 M. The transference number was obtained by measuring the concentration change near the electrodes after an applied current. This concentration change can be determined using calibrated cell potential measurements or custom spectroelectroscopic measurements. A steady-state current experiment was also conducted for comparison. This is a conventional measurement of the transference number in dilute limit.4 Deviations between these two measurements are an indication of non-ideality that can be the result of interactions between the ions and the EO segments and/or the existence of ion pairs and multiplets, which are expected in concentrated systems. The spectroelectroscopic experiment would provide more accurate measurement of the transport properties for concentrated solid electrolyte with reduced errors and practical information for the improvement of battery performance. References Pesko, D. M.; Timachova, K.; Bhattacharya, R.; Smith, M. C.; Villaluenga, I.; Newman, J.; Balsara, N. P., Negative Transference Numbers in Poly(ethylene oxide)-Based Electrolytes. 2017; Vol. 164, pp E3569-E3575.Timachova, K.; Watanabe, H.; Balsara, N. P. Macromolecules 2015, 48, (21), 7882-7888.Ma, Y. P.; Doyle, M.; Fuller, T. F.; Doeff, M. M.; Dejonghe, L. C.; Newman, J. Journal of the Electrochemical Society 1995, 142, (6), 1859-1868.Bruce, P. G.; Vincent, C. A. Journal of electroanalytical chemistry and interfacial electrochemistry 1987, 225, (1-2), 1-17.

Challenges and potentials of forward osmosis process in the treatment of wastewater

An emerging osmotically driven membrane process, forward osmosis has attracted growing attention in the field of desalination and wastewater treatment. The present study provides a critical review of the forward osmosis process for wastewater treatment focusing on most recent studies. Forward osmosis is one of the technologies that has been widely studied for the treatment of a wide range of wastewater because of its low fouling and energy consumption compared to conventional techniques for wastewater treatment. To date, forward osmosis has limited applications in the field of wastewater treatment due to several technical and economic concerns. Although membrane cost is one of the critical issues that limit the commercial application of forward osmosis, there are other obstacles such as membrane fouling, finding an ideal draw solution that can easily be recycled, concentration polarization and reverse salt diffusion. Innovative technologies for in-situ real-time fouling monitoring can give us new insights into fouling mechanisms and fouling control strategies in forward osmosis. This study evaluated recent advancements in forward osmosis technology for wastewater treatment and the main challenges that need to be addressed in future research work.