Solution-Diffusion–Electro-Migration model and its uses for analysis of nanofiltration, pressure-retarded osmosis and forward osmosis in multi-ionic solutions

Predicting the Rejection of Major Seawater Ions by Spiral-Wound Nanofiltration Membranes

“…Overall, these simulation results indicate that the Nernst− Planck equation, that is, the ENP equation without the convection term, also known as Solution-Diffusion-Electromigration, 19,25 is sufficient for modeling seawater nanofiltration. The electromigration was shown to be important for this system, the extent of its effect varying with changes in the feed composition.…”

“…Yet, Yaroshchuk showed in some cases, for example, a combination of a dominant salt with a trace ion leading to a nonlinear dependence, all ionic permeabilities could be deduced and constant permeabilities can produce a reasonably accurate description. 18,19 The present model considers the five major seawater ions, that is, Na + , Cl − , Ca 2+ , Mg 2+ , and SO 4 2− . Since Na + and Cl − rejections by NF membranes are typically low, especially at seawater salinity, it can be concluded that the membrane permeability for these ions is much higher than for the divalent ions.…”

Mixed draw solutions for improved forward osmosis performance

“…The reason for the reduced RSF and relatively constant water flux using seawater as a DS compared to NaCl was not explained by Coday et al; however, there have been several studies on coupled solute flux in FO [15,20,21,25] and preliminary modeling on the hindered transport of monovalent ions for mixed salt solutions [29] that provide insight into the mechanisms behind these results. Hancock et al [15,20] and Phillip et al [25] examined the coupled transport of ions across FO membranes between the feed stream and the concentrated DS using an array of solutes in each stream.…”

“…In a transport modeling effort, Yaroshchuk et al [29] included electrostatic interactions to the solution-diffusion model to determine if the diffusion of small monovalent ions would be hindered in the presence of divalent ions that are well rejected by the membrane. Results from the modeling effort illustrated that solute flux of sodium and chloride could be hindered in the presence of minor concentrations of divalent ions due to spontaneously arising electric fields.…”

Lab scale assessment of power generation using pressure retarded osmosis from wastewater treatment plants in the state of Kuwait

“…Recent studies have focused on the details of water and salt transportation through PRO membranes [18,19], new membrane materials and structures that can enhance water permeability and energy density [20][21][22], the effects of fouling on PRO membranes [23][24][25][26], and the viability of desalination plants hybridized with PRO systems [27][28][29][30][31]. Researchers have also investigated new membrane module designs such as the modified spiral-wound membrane or optimized hollow-fibre designs [32,33].…”