Binary Salt Solutions Research Articles

Selective divalent/monovalent ion partitioning in cation exchange membranes

The selective partitioning of divalent and monovalent counterions through cation exchange membranes immersed in 2:1 and 1:1 binary salt solutions remains unclear, especially at the molecular level. We present a theoretical framework that quantifies these membranes’ sorption of divalent and monovalent ions, incorporating condensed and free variants to reconcile deviations from the ideal Donnan picture observed in published experimental data. This framework explores the membranes’ global and local selective ion sorption characteristics by assessing the effects of competitive ion condensations, where these counterions compete to bind to the fixed charge groups. First, we calculate the thermodynamic property—the global partition ratio—of the membranes immersed in these binary salt solutions, quantifying the partitioning between the binary salt solutions and the membranes. Our theoretical results successfully capture the published experimental partitioning data for membranes immersed in equimolar and non-equimolar 2:1 and 1:1 binary salt solutions. Furthermore, the Donnan potential of the membranes reciprocally changes with the total concentration of 2:1 and 1:1 external salt solutions. However, for the non-equimolar systems at a constant low total concentration, varying the binary solution concentration ratio of 2:1 to 1:1 salts maintains a strong electric potential intensity due to high ionic imbalance. Second, we quantify the local partitioning of the sorbed counterions that are condensed on the crosslinked polymeric chains and those that are mobile in the interstitial solution of the membrane, a variable that is difficult to access experimentally. Accordingly, we can fractionate the sorbed ions into condensed and free states, which mutually govern the membrane’s kinetic and thermodynamic (global and local partitioning) properties.

Molecular and electrostatic origins of mixed salt partitioning phenomena in uncharged poly(ethylene oxide)-based membranes

Despite the increasing interest in membranes for water purification and resource recovery from aqueous electrolyte mixtures, few studies rigorously investigate the influence of salt solution composition (e.g., mole fraction and total salt concentration) on membrane material properties such as partition coefficients. Here, we systematically investigate the influence of solution composition on the partitioning of ionic species from binary aqueous salt solutions into crosslinked poly(ethylene glycol) diacrylate membranes at fixed ionic strength. These results are compared to partition coefficients observed for pure salt solutions. We observe large systematic deviations between the pure salt and mixed salt ion partition coefficients, indicating that the single salt partition coefficients that are often reported do not describe the more complex and realistic mixed salt scenario. Free energy calculations from molecular dynamics simulations, coupled with equilibrium thermodynamic modeling, indicate that mixed salt partitioning trends result from (i) different ions exhibiting different affinities for the membrane and (ii) the constraint of global electrical neutrality within the membrane. With this physical insight, we develop a simple approach to predicting the concentration of various ions in a membrane equilibrated with a mixed salt solution which requires no adjustable parameters.

The effect of atmospherically relevant aminium salts on water uptake

Abstract. Atmospheric new particle formation is initiated by clustering of gaseous precursors, such as small acids and bases. The hygroscopic properties of those precursors therefore affect the hygroscopic properties of aerosol particles. In this work, the water uptake of different salts consisting of atmospheric small acids and amines was studied computationally using the conductor-like screening model for real solvents (COSMO-RS). This method allows for the prediction of water activities in atmospherically relevant salts that have not been included in other thermodynamics models. Water activities are reported here for binary aqueous salt solutions, as well as ternary solutions containing proxies for organic aerosol constituents. The order of the studied cation species regarding water activities is similar in sulfate, iodate, and methylsulfonate, as well as in bisulfate and nitrate. Predicted water uptake strengths (in mole fraction) conform to the following orders: tertiary > secondary > primary amines and guanidinos > amino acids. The addition of water-soluble organic to the studied salts generally leads to weaker water uptake compared to pure salts. On the other hand, water-insoluble organic likely phase separates with aqueous salt solutions, leading to minimal effects on water uptake.

Compressibility of Lithium Hexafluorophosphate Solutions in Two Carbonate Solvents.

Speed-of-sound measurements are performed to establish how the isentropic bulk modulus K s of the electrolyte system comprising lithium hexafluorophospate (LiPF6) in blends of propylene carbonate (PC) and ethyl methyl carbonate (EMC) varies with salt molality m, mass fraction of PC in the PC:EMC cosolvent f, and temperature T. Bulk moduli are calculated by combining acoustic time-of-flight data between parallel walls of a liquid-filled cuvette with densitometric data for a sequence of binary and ternary salt solutions. Correlations are presented to yield K s (m, f, T) accurately for nine compositions spanning the range m = 0-2 mol kg-1 and f = 0-1, at temperatures T ranging from 283.15 to 313.15 K. Electrolyte compressibility varies most with solvent ratio, followed by salt content and temperature, with K s ranging from 1 to 3 GPa. Composition-dependent acoustical properties elucidate the nature of speciation and solvation states in bulk electrolytes, and could be useful to identify the features of individual phases within solution-permeated porous electrodes.

An isoporous ion exchange membrane for selective Na+ transport

Biological sodium channels have selectivity filters with extraordinary Na+ selectivity. Realizing this function in ion exchange membranes is highly desirable for technologies related to water, energy, and the environment, but it remains a challenge. Here we report a sodium selective isoporous membrane (NaSIM) derived from lyotropic liquid crystals. This membrane consists of uniform ion conductive channels lined with carboxylate groups. These negatively charged ion channels demonstrate charge-governed ion transport, pH responsiveness, and Na+ selectivity. The Na+ selectivity was 1.88 against K+ as revealed from single ion permeation experiment and approached 2.10 in binary salt solutions. The prominent Na+ selectivity may arise from specific interactions between Na+ ions and the carboxylate groups inside the channels, which regulate the energy barriers for monovalent cation transfer. The NaSIM we developed may promote high-precision separation and provides a cornerstone for designing a new generation of ion selective membranes.

Investigation of the Effect of Mixed Anion and Mixed Metal on Heavy Metal Removal from Contaminated Aqueous Solutions

Aims: To investigate the effect of variation of metals (Cu vs Zn) and anions (nitrate vs sulfate) in heavy metal remediation by charcoal and coffee waste from contaminated water.
 Study Design: Aqueous solution of single and mixed nitrate and sulfate salts of copper and zinc were respectively treated with charcoal and coffee waste for 12 hr and the residual metal concentration and percent metal removal were determined.
 Place and Duration of Study: The experiments were conducted in the Chemistry Department at Dillard University between January 2021 and November 2021
 Methodology: Coffee waste (2 grams) and charcoal (2 grams) were respectively mixed with 40 ml of 500 parts per million (ppm) of each of the following combination of metal solutions: Cu(NO3)2; CuSO4; Zn(NO3)2; ZnSO4; Cu(NO3)2 and Zn(NO3)2; CuSO4 and ZnSO4; Zn(NO3)2 and ZnSO4; Cu(NO3)2 and CuSO4; Cu(NO3)2 and ZnSO4; Zn(NO3)2 and CuSO4. Each solution was agitated for 12 hours at room temperature. The mixtures were centrifuged at 3000 rpm for 10 minutes and residual copper and zinc were analyzed. The results showed that copper was preferentially adsorbed by coffee waste compared to zinc in all binary metal (copper-zinc) solutions. Copper removal by coffee waste from CuSO4 and CuSO4-ZnSO4 were 43.9% and 65.5% respectively. Zinc removal from ZnSO4 and CuSO4-ZnSO4 by coffee waste was 34.79% and 20.3% respectively. Conversely, the zinc removal from mixed copper-zinc salt solutions, CuSO4-ZnSO4 and Cu(NO3)2-Zn(NO3)2 were 70.5% and 79.9% respectively.
 Conclusion: Metal type can affect the extent of metal removal from mixed metal solutions. In this research, the copper was 21% more effectively removed from the mixed metal solutions than from a single metal-single anion solutions. In addition, zinc removal was11-14% suppressed in binary metal salt solutions compared to its removal from single-metal-single anion salt solutions. The anion type does not influence metal removed from single metal-single anion salt solutions. However, in the mixed metal-mixed anion systems, more metals were removed when the anion is a nitrate than when it is a sulfate, especially with coffee waste as adsorbent. 9.4% more zinc was removed from CuSO4-Zn(NO3)2,79.9%) than from ZnSO4-Cu(NO3)2, 70.5%). Thus, both metal and anion type affect extent of metal removal from mixed metal mixed anion.

Electrochemically activated layered manganese oxide for selective removal of calcium and magnesium ions in hybrid capacitive deionization

Selective removal of ions is a promising new venture with tremendous upsides for resource recovery and sustainability. Traditional methods such as membrane filtration, electrodialysis or ion-exchange resins are either non-selective or too expensive. To fulfil the gap in technology, a hybrid capacitive deionization (HCDI) device utilizing an electrochemically activated layered MnO2 cathode was proposed. The cathode was infused with structural water and can effectively screen strong electrostatic repulsions from Mn atoms within the MnO2 layers, enabling preferential intercalation of divalent cations Ca2+ and Mg2+. Comparative ion removal experiments showed a high selectivity of Ca2+ over K+ (SD/M = 18.0) and Mg2+ over K+ (SD/M = 17.5) at a discharge current of 10 mA g−1 in equimolar binary salt solutions. Preferential divalent cation removal was even maintained in solutions where the ionic strength of monovalent cations was equivalent to divalent cations. In-situ Raman spectroscopy furthered showed that the intercalation of cations resulted in the replacement of water molecules which consequently altered the intensities of v1 and v2 bands of MnO2. The extent of water replacement was characterized by a change in the ratio of v2to v1 intensity and higher divalent cation selectivities were observed to follow smaller changes in intensity ratio.

LiNi0.5Mn1.5O4-based hybrid capacitive deionization for highly selective adsorption of lithium from brine

In recent years, the demands for lithium are increasing sharply with the fast development of electrical vehicles, new green energy and portable electronic devices. To meet the demands, selective recovery of lithium from brine/seawater has attracted extensive attention. LiMn2O4 (LMO) is a good redox material for lithium recovery. However, the dissolution of Mn is inevitable during the redox process which can lead to severe capacity decay and poor cycle performance. In this paper, LiNi0.5Mn1.5O4 (LNMO) nanoparticles were prepared through one-step solid-state sintering and applied as a positive electrode in the hybrid capacitive deionization cell for lithium recovery. Cyclic voltammetry (CV) scan of the LNMO electrode in LiCl aqueous solution presented clear redox peaks, illustrating the reversible intercalation/de-intercalation of Li+ into/from LNMO; while the Na+, K+, Mg2+ and Ca2+ cations had negligible intercalation. Combined with an activated carbon (AC) negative electrode, the hybrid capacitive deionization cell (LNMO||AC) was assembled to selectively adsorb lithium, arriving at the adsorption amount of ~260 µmol/g, almost three times higher than that of the symmetric AC cell (AC||AC). Even in the Mg2+ and Li+ mixed binary salt solution at a high CMg2+/CLi+ ratio of 30, LNMO remained high selectivity to Li+ with the separation factor of ~104 achieved. In the synthetic brine water containing various salts, the LNMO||AC cell kept excellent selectivity to Li+ with the adsorption amount still remaining ~230 µmol/g. And the cell can preserve a retention of ~86% after 100 cycles, much higher than the LMO||AC cell (~50%). Meanwhile, neither Mn2+ nor Ni2+ were found in the cycling solution of LNMO||AC cell. Nevertheless, the LMO||AC cell deteriorated gradually with the dissolution loss ratio of Mn in LMO close to 40%. Such excellent selectivity and high stability of LNMO enable it applicable for practical lithium recovery application, superior to LMO.

Determination of densities, apparent molar volume and apparent molar volume of transfer of some R4NI salt solutions in NMF-DMSO mixtures using magnetic float densitometer and then to study of ionic Interaction at 303.15 K

Binary solvent mixtures of different (%) compositions have been prepared at 303.15 K using tetra alkyl ammonium iodides (R 4 NI) of 0.02 M to 0.14 M to investigate inter ionic interaction, ion-ion and ion solvent interactions in NMF-DMSO solvent mixture containing large cations of tetra alkyl ammonium iodides (R 4 NI). The densities (ρ 0 ) of binary solvent mixtures and salt solutions have been measured by magnetic float densitometer. The apparent molar volume at infinite dilution ф v 0 , in the solvent mixtures, have been utilized to estimate the apparent molar volumes of transfer ∆ф v 0 (tr), for various tetra alkyl ammonium iodide salts (R 4 NI) from NMF-DMSO mixtures. The observed trend and variations of dielectric constant and density with different (%) composition of NMF – DMSO provide useful information about the structural interactions.

A general model for prediction of BaSO4 and SrSO4 solubility in aqueous electrolyte solutions over a wide range of temperatures and pressures

The aqueous solubility of BaSO4 and SrSO4 in salt-containing solutions plays a crucial role in process industries and oilfield operations. Small variations in thermodynamic conditions result in precipitation and co-precipitation of these salts, mainly owing to their limited solubility in aqueous solutions. Understanding the environmental chemistry of BaSO4 and SrSO4 requires accurate knowledge of their solubility and thermodynamic behaviors. In this study, a general solubility prediction model based on a least square support vector machine and differential evolution algorithm was developed that is able to handle solubility predictions for BaSO4 in single salt solutions containing NaCl, CaCl2, MgCl2, KCl, KBr, Na2SO4, and Na2B4O7, and for SrSO4 solubility, it can handle predictions for single, binary, and ternary salt solutions containing NaCl, CaCl2, and MgCl2 over a wide range of temperatures and pressures. Model predictions agree excellently with experimental measurements, yielding an overall correlation coefficient (R2) of 0.9911 and an Average Absolute Error of 6.24%. A comparison of the general solubility prediction model with the Pitzer ion-interaction model revealed that both the models perform well in single salt solutions, while the Pitzer model fails to produce accurate solubility predictions when the aqueous system is extended to binary and ternary electrolyte mixtures.

Effects of Divalent Salts on the Interfacial Activity of the Mixed Surfactants at the Water/Model Oil Interface

AbstractIn our previous report, the mixed cationic/anionic surfactant system consisting of N‐dodecyl‐N‐methylpyrrolidinium bromide (L12) and sodium dodecyl sulfate (SDS) showed good interfacial tension (IFT) reduction of water/model oil (Vtoluene:V n‐decane = 1:1). In the present study, the effects of divalent salts (MgCl2 or CaCl2) on the interfacial activity were systematically evaluated. The additional Mg2+ ions greatly reduced the IFT to an ultralow value, whereas Ca2+ ions caused the generation of the precipitates and resulted in increased IFT values. The precipitates disappeared in binary divalent salt solutions, and the IFT values remained at a low level. Based on the valence, polarizability, and hydrated radius of the ions, we proposed a model to explain the abnormal changes. The effects of NaCl and temperature were investigated to further verify our proposed mechanism. Moreover, the additional divalent salts obviously enhanced the stability of L12/SDS stabilized emulsions.

Studies on change of strain developed in different wood samples due to change in relative humidity

In this paper the dimensional change of different varieties of wood blocks due to change in relative humidity (RH) is presented. The dimensional change of wood due to variation of RH is measured in terms of strain. For this purpose, a strain measuring system is developed in the laboratory. The developed system is used to measure temperature, RH and strain of wood samples due to change in RH. Seventeen wood blocks of different thickness and different orientations are studied. Out of these, strain sensitivity of three samples covering the measured range of values is presented in this paper. The strain variation of the wood samples is tested in different humidity levels generated by the method of binary salt solutions at constant temperature 25 °C. The results obtained show different levels of strain developed in different species of wood. The change of strain is found to depend on the types of wood, thickness of the samples and orientations.

Study of the Influence of Alkyl Chain Cation Solvent Interactions on the Slope of ϕv v/s √C Curves in 1, 3-Butanediol-DMF Solvent Mixtures by Apparent Molar Volume Measurements

The concept of Frank's hypothesis (that is the effect of large tetra alkyl ammonium ions on the solvent structure, especially water, in the ion-ion and ion-solvent interactions) was found to be not applicable when water was replaced by one of the organic solvents e.g. Dimethyl formamide (DMF), in the solvent mixture, that is, if the study involves ion-ion and ion- solvent interactions in 1,5-pentane diol - DMF solvent mixture containing large cations of tetraalkyl ammonium iodides. The densities of binary solvent mixtures and salt solutions have been measured at 298.15 K by magnetic float densitometer. The apparent molar volumes at infinite dilution, ФV 0 , determined by ФV -values in the solvent mixtures, have been utilized to estimate the partial molar volumes of transfer, ΔФV 0 (tr), for various tetraalkyl ammonium iodide salts from DMF to 1,5-Pentane diol.

Measurement and modelling of water activity of aqueous poly (ethylene glycol) or poly (propylene glycol) + sodium potassium tartrate and corresponding binary salt solutions

Water activity values of ternary aqueous sodium potassium tartrate (Na–K Tar)+poly (ethylene glycol) or poly (propylene glycol) solutions were measured using the isopiestic method at T=298.15K. Also the water activity for corresponding binary aqueous sodium potassium tartrate (Na–K Tar) solutions was measured at T=(298.15, 308.15, 318.15)K. The obtained water activity values for binary aqueous sodium potassium tartrate (Na–K Tar) system were successfully fitted with the local composition and Pitzer models. The mean activity coefficients for the studied binary salt solutions have been calculated. The thermodynamic behaviour of aqueous {(Na–K Tar)+poly (ethylene glycol) or poly (propylene glycol)} solutions was discussed on basis of water, polymer and salt interactions.

Measurements of the density, speed of sound, viscosity and derived thermodynamic properties of geothermal fluids from south Russia Geothermal Field. Part II

Density, (ρ), speed of sound, (W), and viscosity, (η) of natural geothermal fluids from south Russia Geothermal Fields (Dagestan, Caspian seashore) have been measured over the temperature range from (277–353) K at atmospheric pressure. The measurements were made using the Anton Paar DMA4500 densimeter and Stabinger SVM3000 viscodensimeter for four geothermal fluid samples from the various hot-wells Izberbas (No. 68 and 129), Ternair (No. 27T and No. 38T). A sound-speed analyzer (Anton Paar DSA 5000) was used for simultaneously measurement of the speed of sound and density of the same geothermal fluid samples. The average differences between the measured geothermal fluids densities and viscosities and pure water values (IAPWS formulation) are within (0.1–1.77) % and (0.13–2.1) %, respectively, which are considerably higher than their experimental uncertainties. This differences are caused by the high concentrations of some type of ion species, such as (Na+: 7.7 g/l (#38T); Cl−1:7.7 g/l (#38T); SO4−2: 0.75 g/l (#68); S+: 0.24 g/l (#68); K+:0.15 g/l (# 27T); Ca+2: 0.074 g/l (#27T); B+:0.06 g/l (#38T); and Mg +2: 0.033 g/l (#38T)), in the geothermal fluids, which strongly effect on salt concentration dependence of the measured properties. Measured values of density and speed of sound were used to calculate other derived thermodynamic properties such as adiabatic coefficient of bulk compressibility (βS), coefficient of thermal expansion (αP), thermal pressure coefficient (γV), isothermal coefficient of bulk compressibility (βT), isochoric heat capacity (CV), isobaric heat capacity (CP), enthalpy difference (ΔH), partial pressure derivative of enthalpy (∂H∂P)T, and partial derivatives of internal energy (internal pressure) (∂U∂V)T, of the geothermal fluid samples. Measured values of density, viscosity, and speed of sound were used to develop correlation models for the temperature and ion species concentration dependences, which reproduced the measured values within 0.03% (density), 2.47% (viscosity), and 0.20% (speed of sound). To confirm the accuracy and predictive capability of the developed correlation models for density, speed of sound, and viscosity, we have applied the models to well-studied binary aqueous salt solutions (H2O + NaCl). The prediction of the density and viscosity of aqueous sodium chloride solutions based on the developed models were very close to their experimental uncertainties (within 0.03% for density and 1.56% for viscosity). The measured properties at atmospheric pressure have been used as a reference data for prediction of the high-pressure thermodynamic behavior. The predictive capability of the model has been checked on reliable experimental data for binary aqueous NaCl solutions at high pressures reported by Kestin and Shankland (1984) and Rogers and Pitzer (1982). The prediction for density and viscosity is within 0.03% and 1.57%, respectively.

Selective separation of chloride and sulfate by nanofiltration for high saline wastewater recycling

Abstract In order to effectively separate chloride (such as NaCl) and sulfate (such as Na2SO4) for high saline wastewater recycling, one commercial NF membrane (named Desal-DL) was employed in the permeation of the single and binary salt solutions of NaCl and Na2SO4 with a lab-scale cross-flow batch module, where the salt concentration ranged from 4 to 96 g L−1 and the operating pressures varied from 0.6 to 2.4 MPa as well as the temperature was kept under room temperature. The experimental results showed that the Desal-DL NF membrane had a low rejection to NaCl and a high rejection to Na2SO4 for single salt solutions. While for binary salt solutions, the membrane presented a bit higher rejection to SO42− and much lower rejection to Cl−, even special negative rejection to Cl− was observed when the concentration of Na2SO4 was high. This implies that NF is suitable to be used for the separation of Na2SO4 and NaCl from their binary solution, where Na2SO4 could be retained by the NF membrane and concentrated to high concentration while NaCl could pass through the membrane and might be diluted to low concentration with a diafiltration operation mode. Finally the selective separation of Na2SO4 and NaCl by NF diafiltration was simulated for the binary salt solution containing 23.4 g L−1 NaCl and 8.76 g L−1 Na2SO4. A highly concentrated solution of Na2SO4 (71.74 g L−1) and a relatively pure solution of NaCl (20.79 g L−1) were obtained, which favored the post-treatment of high saline wastewater for inorganic salts recycling.

Influence of ion interaction on lead removal by a polyamide nanofiltration membrane

Retention of lead(II) ions on a polyamide nanofiltration membrane was investigated. Effects of different factors including operating pressure, lead ion concentration, anion nature, pH and composition of feed on the lead ion rejection were studied. The solutions used consisted of Pb(NO3)2, PbCl2 and PbSO4 in the single-salt solution system and Pb(NO3)2, Cu(NO3)2, Zn(NO3)2, Cd(NO3)2, NaNO3 and NH4NO3 in the binary-salt solution system. The influence of divalent and monovalent cations including cadmium, copper, zinc, sodium and ammonium on the rejection of lead ion was examined. The transmembrane pressure and lead ion concentration varied between 10 and 40bar and 20 and 400mg Pb2+/L, respectively. It was observed that increasing the pressure and initial feed concentration resulted in a higher lead ion rejection. By replacing NO3− with Cl− andSO42−, the rejection of lead ion increased about 2% and 9%, respectively. Applying anions with higher valences resulted in a higher lead ion rejection and lower permeate flux. Maximum permeate flux and minimum lead ion rejection was observed at pH5.6. In the binary salt solutions, the rejection of lead did not change significantly in the presence of monovalent cations. However, the presence of divalent cations caused a substantial reduction in the lead ion rejection.

Design and Characterisation of a Temperature Compensated Relative Humidity Measurement System with On Line Data Logging Feature

A method of relative humidity (RH) measurement with on line temperature correction and data logging feature is described here. The RH sensor is a thermoset polymer capacitive type with on chip conditioning. Output voltage of RH to voltage converter is digitised using a 12-bit A/D converter and it is interfaced with an 8-bit microcontroller. Temperature correction of RH in real time is done using a temperature to digital converter interfaced with the microcontroller. The corrected data is displayed in a liquid crystal display and transmitted for on line monitoring and logging via RS232C. Calibration of the system is performed using standard saturated binary salt solutions. Accuracy and precision are found out. Hysteresis and ageing effect is discussed. The system performance is also compared with a dry/wet bulb psychrometer at different ambient conditions. The performance of the system in an industrial environment is presented.

Development of an Online Heat Index Measurement System for Thermal Comfort Determination

This paper presents the development of a reliable heat index (HI) measurement system for evaluating the thermal comfort of a particular building or a particular area. The HI is an index that combines air temperature and relative humidity (RH) to determine the human-perceived equivalent temperature. To measure the air temperature and RH, temperature to digital converter and RH to voltage converter is used. HI is calculated online with the help of embedded firmware of the microcontroller. This calculated value is then transferred to the computer through standard RS 232 serial port. The same sensor node is tested with the RS 485 network standard by changing the transceiver of the node. The system is calibrated using four standard saturated binary salt solutions.

Development of nanofiltration membrane separation prediction system for binary salt solutions

The previous studies on nanofiltration (NF) mainly focused on the work to update the existing predictive models to enhance its application in order to optimize the separation prediction. There is still lack of research which successfully creates a user-friendly system for separation process prediction optimization. In this study, a MATLAB®-based NF prediction system (NF-BIN) utilizing Donnan Steric Pore model with application of m-file programming and graphical user interface was developed specifically for binary salt solutions treatment. Prior to the prediction, locally fabricated polyethersulfone membranes with three different polymer concentrations, 19, 21, and 23%, were characterized in terms of pore radius, rp ratio of membrane thickness to porosity, Δx/Ak and effective charge density, Xd using uncharged, and charged solutes rejection data. Further the rejection prediction performance was carried out to predict the percentage contribution of ion transport mechanism of three transport modes: diffusion, electromigration, and convection as described in Extended Nernst–Planck equation. The results obtained from this study indicated that NF/BIN has a good potential as an ideal predictor of NF membrane separation behavior.