Chemical binding of jojoba liquid wax to polyethylene

Jojoba wax was chemically bonded to polyethylene—in film or hollow fiber form—via a stable sulfonamide bond. The jojoba-bonded polyethylene was obtained by binding allyl amino jojoba derivatives to chlorosulfonated polyethylene. The amount of jojoba added to the polymer ranged from 9 to 98% (w/w), depending onthe reaction conditions. Swelling of the polymer in the reaction solvent was the major factor affecting the efficacy of the chemical binding of the jojoba amino groups to the chlorosulfonyl entities of the polymer. The double-bond regions in the bound jojoba wax were preserved, i.e., they were shown to be reactive in a bromination reaction. These modified membranes can find application in separation processes, such as metal ion separation and pervaporation.     

Pervaporation separation of water–ethanol mixtures using metal‐ion‐exchanged poly(vinyl alcohol) (PVA)/sulfosuccinic acid (SSA) membranes

Poly(vinyl alcohol)/sulfosuccinic acid (PVA/SSA) membranes in the hydrogen form were converted to monovalent metal ion forms Li⁺, Na⁺, and K⁺. The effect of exchange with metal ions was investigated by measuring the swelling of water–ethanol (10/90) mixtures at 30 °C and by the pervaporative dehydration performance test for aqueous ethanol solutions with various ethanol concentrations at 30, 40, and 50 °C. In addition, electron spectroscopy for chemical analysis (ESCA) analysis was carried out to study the quantity of metal ions in membranes. From the ESCA analysis, the lithium ion quantity in the resulting membranes is greater than that of any other metal ions in question because of the easy diffusion of a smaller metal ion into the membrane matrix. The swelling ratio was in the following order: PVA/SSA‐Li⁺ > PVA/SSA‐Na⁺ > PVA/SSA‐K⁺ membranes. For pervaporation, the PVA/SSA‐Na⁺ membrane showed the lowest flux and highest separation factor for all aqueous ethanol solutions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1867–1873, 2002     

Pervaporation separation of dimethyl carbonate/methanol mixtures with regenerated perfluoro‐ion‐exchange membranes in chlor‐alkali industry

The waste perfluoro‐ion‐exchange membranes (PFIEMs) in chlor‐alkali industry were regenerated and used to the separation of dimethyl carbonate (DMC)/methanol (MeOH) mixtures by pervaporation process. The energy‐dispersive spectrum (EDS) demonstrates that the impurities on the surfaces of waste PFIEMs can be effectively cleared by the regeneration process. The degree of swelling, sorption, and pervaporation properties of the regenerated PFIEMs with different counter ions were investigated. The results indicate that the counter ions of PFIEMs conspicuously influence the degree of swelling, sorption, and pervaporation properties for DMC/MeOH mixtures. The degree of swelling and solubility selectivity both decreases with the alkali metal counter ions in the sequence: Li⁺ > Na⁺ > K⁺ > Cs⁺. The degree of swelling increases with MeOH concentration increasing in feed liquid. The pervaporation measurements illustrate that the permeation flux decreases and the separation factor increases with the rising in ion radius of counter ions. The increase of feed concentration (MeOH) and feed temperature is advantageous to improve permeation flux while at the cost of separation factor decreasing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Pushing the limits of high performance dual‐layer hollow fiber fabricated via I2PS process in dehydration of ethanol

The immiscibility induced phase separation (I²PS) process was introduced as a novel method to fabricate hollow fibers with exceptionally high water permeance and reasonably high water/ethanol selectivity in dehydration of ethanol by pervaporation. As a continuation of the previous work, this study discloses the mechanisms to enhance the performance of hollow fibers spun via I²PS by elucidating the material selection at the inner‐layer. Moreover, it revealed the methods to reduce mass‐transport resistance by enhancing surface porosity for both inner and outer surfaces to further improve the permeation flux of the membranes. The continuous performance test demonstrates that the fibers spun from the I²PS possess a stable dehydration performance throughout the monitored period of 300 h. A comparison with pervaporation membranes in the literatures verifies the superiority of the membranes spun via I²PS process with the highest water permeation flux of 9.5 kg/m² h and the permeate water purity of 95.8 wt % at 80°C. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3006–3018, 2013     

Preparation of high‐performance zeolite NaA membranes in clear solution by adding SiO2 into Al2O3 hollow‐fiber precursor

Zeolite NaA membranes were prepared in a clear synthesis solution without the aid of nanoseeds. To improve the properties of the membranes formed in a clear solution, alumina hollow fibers were fabricated by adding silica powder to the conventional spinning slurry, resulting in hollow fibers with a mullite phase. Prior to the membrane synthesis, the hollow fibers were pretreated by dipping in an aged synthesis solution diluted with isopropanol. Dense zeolite NaA membranes on mullite‐containing alumina hollow fibers were successfully obtained at 100°C for 2 h without the aid of nanoseeds. The membranes have a good pervaporation performance with a high flux of 10.8 kg m^?2 h^?1 and a separation factor of over 10,000. The abundant mullite‐phase hydroxyl groups on the support surface promote the nucleation and growth of zeolite crystals on the support, resulting in dense membranes. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2679–2688, 2018     

Separation and extraction of some heavy and toxic metal ions from their wastes by grafted membranes

Preparation and characterization of a series of ion‐exchange membranes for the purpose of separation and extraction of some heavy and toxic metal ions from their wastes were studied. Such ion‐exchange membranes were prepared by γ‐radiation grafting of acrylonitrile (AN) and vinyl acetate (VAc) in a binary monomer mixture onto low‐density polyethylene (LDPE) using the direct technique of grafting. The reaction conditions at which the grafting process proceeds successfully were determined. Many modification treatments were attempted for the prepared membranes to improve their ion‐exchange properties. The possibility of their practical use in waste‐water treatment to remove some heavy and toxic metal ions such as Pb²⁺, Cd ²⁺, Cu²⁺, Fe³⁺, Sr²⁺, and Li⁺ were investigated. These grafted membranes showed great promise for possible use in the field of extraction and removal of some heavy and toxic metals from their wastes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 849–860, 2001     

Pervaporation of ethanol-water mixtures through poly(vinyl alcohol-g-acrylic acid) membranes prepared by use of Fenton's reagent in grafting

Ionic crosslinking of the ferric ions and the carboxylic groups in the poly(vinyl alcohol-g-acrylic acid) (poly(VA-g-AA)) membranes improves the size screening effect in the pervaporation of ethanol-water separation. In the grafting polymerization of acrylic acid monomer onto poly(vinyl alcohol) (PVA), ferric ions are remained in the polymer membranes as the Fenton's reagent(Fe²⁺-H₂O₂) is used to initiate the reaction. Completely reversed trends in terms of the degree of swelling, the pervaporation selectivity, and the flux of permeates are obtained depending on that the ferric ions are present or absent in the membranes. The degree of swelling decreases, the pervaporation selectivity increases, and the flux decreases as the grafting percentage increases for the membranes containing ferric ions. The degree of swelling and the flux of permeates increase but the pervaporation selectivity is reduced as the grafting percentage increases for the membranes which were washed with acid to remove ferric ions.     

Effect of operation conditions in the pervaporation of ethanol–water mixtures with poly(1‐trimethylsilyl‐1‐propyne) membranes

Poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) is known to show preferential permeation of ethanol in the pervaporation of ethanol–water mixture. Although this polymer presents good characteristics for the separation of organic–water solutions, operation conditions and membrane characteristics, such as thickness, affect its pervaporation performance. The effect of temperature and feed concentration on pervaporation was studied. During pervaporation of 10 wt % ethanol–water solution, the separation factor (α_H2O^EtOH) remains almost constant, whereas the permeation flux (F) increases exponentially with operation temperature. On the other hand, the separation factor decreases, whereas the permeation flux increases with ethanol content in the feed mixture. The membrane thickness also affects the performance of PTMSP polymer films: selectivity increases sharply with membrane thickness up to 50 μm, whereas it remains constant for thicker membranes. The permeation flux decreases with membrane thickness in the whole range studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94:1395–1403, 2004     

Hydrophilic hollow fiber membranes for water desalination by the pervaporation method

Hydrophilic ion-exchange membranes based on sulfonated polyethylene hollow fibers were manufactured, and their suitability for a water pervaporation process was studied for possible application in water desalination systems. The effects of the following parameters on the average water flux were determined: membrane properties (diameter (0.4–1.8 mm) and wall thickness (0.05–0.18 mm)); charge density (0.6–1.2 meq g⁻¹); and operating conditions (brine inlet temperature (30–68°C), air sweep velocity (0–6 m s⁻¹), and salt concentration in the feed brine (0–3 M)). A water flux of 0.8–3.3 kg m⁻² h⁻¹ was obtained using this type of hollow fiber with an inlet brine temperature of 25–65°C. It was found that, for our application, the optimal specifications for the ion-exchange hollow fibers were an outside diameter of 1.2 mm, a wall thickness of 0.1 mm, and an ion-charge density of about 1.0 meq g⁻¹. This information is required as basic data for the design of a prototype water desalination system based on a pervaporation system that uses this type of ion-exchange hollow fiber membrane.     

Removal of N‐butanol from aqueous solutions by ion–exchange membranes containing organic counterions

The pervaporation of aqueous butanol solutions was investigated using thin‐film composite membranes composed of a poly(vinylidene fluoride) substrate coated with a sulfonated poly(2,6‐dimethyl‐1,4‐phenelene oxide) polymer. The polymer was ion‐exchanged with quaternary ammonium cations having aliphatic substituents of various chain lengths. The pervaporation of aqueous n‐butanol solutions using these membranes gave a permeate more concentrated in n‐butanol; therefore, they were alcohol‐selective. The separation factor increased and the permeate flux decreased as the chain lengths of the aliphatic substituents were increased. Hence, the mass‐transport properties of such membranes can be controlled or altered to yield some desired permselectivity by the introduction of a proper counterion. It was observed that the n‐butanol flux was small relative to the total flux and, therefore, the water flux dominated the total permeate flux. The degree of swelling of the membranes and its effect on membrane performance was investigated as well. As the n‐butanol content was increased, the swelling of the membranes increased greatly. High membrane swelling caused a reduction in the separation factor. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 47–58, 1999     

Synthesis and characterization of polyacrylamide‐grafted sodium alginate copolymeric membranes and their use in pervaporation separation of water and tetrahydrofuran mixtures

Polyacrylamide‐grafted sodium alginate (PAAm‐g‐Na‐Alg) copolymeric membranes have been prepared, characterized, and used in the pervaporation separation of 10–80 mass % water‐containing tetrahydrofuran mixtures. Totally three membranes were prepared: (1) neat Na‐Alg with 10 mass % of polyethylene glycol (PEG) and 5 mass % of polyvinyl alcohol (PVA), (2) 46 % grafted PAAm‐g‐Na‐Alg membrane containing 10 mass % of PEG and 5 mass % of PVA, and (3) 93 % grafted PAAm‐g‐Na‐Alg membrane containing 10 mass % of PEG and 5 mass % of PVA. Using the transport data, important parameters like permeation flux, selectivity, pervaporation separation index, swelling index, and diffusion coefficient have been calculated at 30°C. Diffusion coefficients were also calculated from sorption gravimetric data of water–tetrahydrofuran mixtures using Fick's equation. Arrhenius activation parameters for the transport processes were calculated for 10 mass % of water in the feed mixture using flux and diffusion data obtained at 30, 35, and 40°C. The separation selectivity of the membranes ranged between 216 and 591. The highest permeation flux of 0.677 kg/m² h was observed for 93% grafted membrane at 80 mass % of water in the feed mixture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 272–281, 2002     

Engineering design of outer‐selective tribore hollow fiber membranes for forward osmosis and oil‐water separation

Outer‐selective thin‐film composite (TFC) hollow fiber membranes offer advantages like less fiber blockage in the feed stream and high packing density for industrial applications. However, outer‐selective TFC hollow fiber membranes are rarely commercially available due to the lack of effective ways to remove residual reactants from fiber's outer surface during interfacial polymerization and form a defect‐free polyamide film. A new simplified method to fabricate outer‐selective TFC membranes on tribore hollow fiber substrates is reported. Mechanically robust tribore hollow fiber substrates containing three circular‐sector channels were first prepared by spinning a P84/ethylene glycol mixed dope solution with delayed demixing at the fiber lumen. The thin wall tribore hollow fibers have a large pure water permeability up to 300 L m^?2 h^?1 bar^?1. Outer‐selective TFC tribore hollow fiber membranes were then fabricated by interfacial polymerization with the aid of vacuum sucking to ensure the TFC layer well‐attached to the substrate. Under forward osmosis studies, the TFC tribore hollow fiber membrane exhibits a good water flux and a small flux difference between active‐to‐draw (i.e., the active layer facing the draw solution) and active‐to‐feed (i.e., the active layer facing the feed solution) modes due to the small internal concentration polarization. A hyperbranched polyglycerol was further grafted on top of the newly developed TFC tribore hollow fiber membranes for oily wastewater treatment. The membrane displays low fouling propensity and can fully recover its water flux after a simple 20‐min water wash at 0.5 bar from its lumen side, which makes the membrane preferentially suitable for oil‐water separation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4491–4501, 2015     

Preparation and pervaporation performance of chitosan‐poly(methacrylic acid) polyelectrolyte complex membranes for dehydration of 1,4‐dioxane

Polyelectrolyte complex (PEC) membranes composed of chitosan (CS) and poly(methacrylic acid) (PMAA) were prepared by mixing the polymer solutions in different ratios. The chemical interaction and crystallinity of the resulting PEC membranes were respectively analyzed by Fourier transform infrared spectroscopy (FTIR) and wide‐angle X‐ray diffraction (WAXD). Differential scanning calorimetry (DSC) was used to characterize the thermal properties of the membranes. The membranes thus obtained were subjected to pervaporation (PV) separation of water‐dioxane mixtures. Among the PEC membranes, membrane containing 30 wt% ratio of PMAA (M‐3) exhibited the highest separation selectivity of 840 with a flux of 12.07 × 10^?2 kg/m²h at 30°C at 15 wt% of water in the feed. By the incorporation of NaY zeolite into PEC up to 5 wt%, we have been able to overcome the trade‐off phenomenon existing between flux and selectivity in PV process. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The resulting activation energy values obtained for water permeation (E_pw) are much lower than those of dioxane permeation (E_po), suggesting that the developed membranes have higher separation efficiency for water‐dioxane system. Based on the heat of sorption (ΔH_s) values, the mode of sorption was discussed. POLYM. ENG. SCI., 56:715–724, 2016. © 2016 Society of Plastics Engineers     

Characterization of graft polymerization of fluoroalkyl methacrylate onto PDMS hollow‐fiber membranes and their permselectivity for volatile organic compounds

Polydimethylsiloxane (PDMS) hollow‐fiber membranes grafted with 1H,1H,9H‐hexadecafluorononyl methacrylate (HDFNMA), which is a fluoroalkyl methacrylate, using a ⁶⁰Co irradiation source, were characterized and applied to pervaporation. The PDMS hollow‐fiber membranes were filled with N₂ gas and sealed. The membranes and the HDFNMA solution were then irradiated simultaneously. In the HDFNMA solution, graft polymerization was performed. The degree of grafting of the outside surface of the hollow fiber was greater than that in the inside surface of the hollow fiber. In the grafted PDMS hollow‐fiber membranes, the best separation performance was shown due to the introduced hydrophobic polymer, poly(HDFNMA). The grafted membrane had a microphase‐separated structure, that is, a separated structure of PDMS and graft‐polymerized HDFNMA. The permeability of molecules in the poly(HDFNMA) phase was so low that the diffusion of molecules was prevented in the active layer with many poly(HDFNMA) domains, as the feed solution was introduced through the inside of the hollow fibers and the outside was vacuumed. As the feed solution was introduced through the outside of the hollow fibers and the inside was vacuumed, the diffusion of molecules was not prevented in the active layer with few poly(HDFNMA) domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1573–1580, 2003     

High‐performance PDMS membranes for pervaporative removal of VOCs from water: The role of alkyl grafting

To improve the pervaporation performance of PDMS membrane, alkyl groups with different chain length were grafted into PDMS matrix. The prepared membranes were characterized by ATR‐IR, DSC, TGA, PALS, and tensile testing. The effects of alkyl grafting on pervaporation performance of PDMS membrane were investigated in separation of ethyl acetate/water mixture. Experimental results show that the separation factor of PDMS membrane is largely improved by alkyl grafting because of the enhanced preferential sorption of ethyl acetate, and this improvement depends on alkyl grafting ratio and alkyl chain length. The total flux of PDMS membrane reduces after alkyl grafting owing to the decreased free volume. When grafting ratio is above 6.9%, membrane grafted with shorter alkyl groups is preferred for pervaporation. The best pervaporation performance is achieved by 9% octyl grafted PDMS membranes with a separation factor of 592 and a total flux of 188 gm^?2 h^?1 in separation of 1% ethyl acetate/water mixture at 40 °C. Moreover, this octyl grafted PDMS membrane also exhibits excellent separation performance in removal of butyl acetate, methyl‐tert‐butyl ether, and n‐butanol from water. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43700.     

Preparation of PFSA‐PVA/PSf hollow fiber membrane for IPA/H2O pervaporation process

Using Na⁺ form of perfluorosulfonic acid (PFSA) and poly(vinyl alcohol) (PVA) as coating materials, polysulfone (PSf) hollow fiber ultrafiltration membrane as a substrate membrane, PFSA‐PVA/PSf hollow fiber composite membrane was fabricated by dip‐coating method. The membranes were post‐treated by two methods of heat treatment and by both heat treatment and chemical crosslinking. Maleic anhydride (MAC) aqueous solution was used as chemical crosslinking agent using 0.5 wt % H₂SO₄ as a catalyst. PFSA‐PVA/PSf hollow fiber composite membranes were used for the pervaporation (PV) separation of isopropanol (IPA)/H₂O mixture. Based on the experimental results, PFSA‐PVA/PSf hollow fiber composite membrane is suitable for the PV dehydration of IPA/H₂O solution. With the increment of heat treatment temperature, the separation factor increased and the total permeation flux decreased. The addition of PVA in PFSA‐PVA coating solution was favorable for the improvement of the separation factor of the composite membranes post‐treated by heat treatment. Compared with the membranes by heat treatment, the separation factors of the composite membranes post‐treated by both heat treatment and chemical crosslinking were evidently improved and reached to be about 520 for 95/5 IPA/water. The membranes post‐treated by heat had some cracks which disappeared after chemical crosslinking for a proper time. Effects of feed temperature on PV performance had some differences for the membranes with different composition of coating layer. The composite membranes with the higher mass fraction of PVA in PFSA‐PVA coating solution were more sensitive to temperature. It was concluded that the proper preparation conditions for the composite membranes were as follows: firstly, heated at 160°C for 1 h, then chemical crosslinking at 40°C for 3 h in 4% MAC aqueous solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Three‐component mixed matrix organic/inorganic hybrid membranes for pervaporation separation of ethanol–water mixture

Mixed matrix membranes (MMMs) were made by incorporating vinyltrimethoxysilane (VTMS)‐modified Silicalite‐1 zeolite nanoparticles (V‐Silicalite‐1 NPs) into fluorinated polybenzoxazine (F‐PBZ) modified polydimethylsiloxane (PDMS) polymer through in situ polymerization method. The membrane morphology, surface wettability, and pervaporation performance were systematically investigated. The addition of F‐PBZ into PDMS membranes resulted in substantially improved flux and marginal increase of separation factor, which is the result of higher free volume and higher hydrophobicity caused by the addition of F‐PBZ. The modification of Silicalite‐1 NPs improved the interfacial contact between zeolite crystals and polymer phase. The incorporation of hydrophobic V‐Silicalite‐1 zeolite NPs into the PDMS membranes led to much higher separation factor but reduced flux, which is the result of increased hydrophobicity and reduced free volume. The three‐component MMMs with V‐Silicalite‐1 zeolite NPs in the F‐PBZ fluorinated PDMS exhibited separation factor of 28.7 and flux of 0.207 kg m^?2 h^?1 for 5 wt % ethanol aqueous solution at 50 °C, while the pure PDMS membranes only had separation factor of 4.8 and flux of 0.088 kg m^?2 h^?1. The substantial increase of both flux and separation factor were attributed to the higher hydrophobicity and free volume caused by the incorporation of both hydrophobic zeolite crystals and F‐PBZ polymer into the PDMS membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44753.     

Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes for pervaporation separation of ethanol/water solution

Polysulfone (PSF) hollow fiber membranes were spun by phase‐inversion method from 29 wt % solids of 29 : 65 : 6 PSF/NMP/glycerol and 29 : 64 : 7 PSF/DMAc/glycol using 93.5 : 6.5 NMP/water and 94.5 : 5.5 DMAc/water as bore fluids, respectively, while the external coagulant was water. Polyvinyl alcohol/polysulfone (PVA/PSF) hollow fiber composite membranes were prepared after PSF hollow fiber membranes were coated using different PVA aqueous solutions, which were composed of PVA, fatty alcohol polyoxyethylene ether (AEO₉), maleic acid (MAC), and water. Two coating methods (dip coating and vacuum coating) and different heat treatments were discussed. The effects of hollow fiber membrane treatment methods, membrane structures, ethanol solution temperatures, and MAC/PVA ratios on the pervaporation performance of 95 wt % ethanol/water solution were studied. Using the vacuum‐coating method, the suitable MAC/PVA ratio was 0.3 for the preparation of PVA/PSF hollow fiber composite membrane with the sponge‐like membrane structure. Its pervaporation performance was as follows: separation factor (α) was 185 while permeation flux (J) was 30g/m²·h at 50°C. Based on the experimental results, it was found that separation factor (α) of PVA/PSF composite membrane with single finger‐void membrane structure was higher than that with the sponge‐like membrane structure. Therefore, single finger‐void membrane structure as the supported membrane was more suitable than sponge‐like membrane structure for the preparation of PVA/PSF hollow fiber composite membrane. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 247–254, 2005     

Preparation of carboxylated graphene oxide nanosheets/polysulphone hollow fibre separation membranes with improved separation and dye adsorption properties

Novel hollow fibre polysulphone (PSF) separation membranes were prepared via the incorporation of carboxylated graphene oxide (cGO) in membrane matrix during the dry‐wet spinning process to improve the membrane performance of water flux and dye adsorption. The surface composition and morphology of the prepared cGO‐incorporated hollow fibre membranes were characterised by means of Fourier Transform–infrared spectra and scanning electron microscopy. The effects of different cGO contents on membrane surface hydrophilicity, separation performance, anti‐compaction and adsorption properties were investigated through measurements of the water contact angle, cross‐flow filtration and methylene blue (MB) adsorption experiments. The results demonstrated that the cGO‐incorporated membranes had more hydrophilic surfaces, higher permeation flux, better anti‐compaction properties and a higher adsorption rate of MB than that of the PSF control membrane. When cGO content was 0.45 wt.%, the pure water flux of the modified membrane increased from 90.56 to 148.26 l m^?2 h^?1 at 0.1 MPa; also, rejections of bovine serum albumin and polyethylene glycol (PEG‐20000) maintained relatively high values of 98.81 and 93.89%, respectively. The incorporation of cGO nanosheets could effectively improve membrane anti‐compaction properties and the adsorption rate of MB.     

Ion-“distillation” for isolating lithium from lake brine

Lithium demands increase dramatically and make it highly attractive to develop advanced ion separation technology/material. However, high Mg²⁺/Li⁺ ratio impedes the extraction due to the difficulties in separation of the two ions. Here, we propose an ion-“distillation” technology based on electro-membrane stacking for the extraction of Li⁺ from lake brine (Mg²⁺/Li⁺ ratio: 31.58). This technology employs commercially available monovalent ion-selective membranes, and ions are driven by electric. Using the four-stage ion-“distillation” technology, selectivity values of 26,177 and 27,000 are achieved between Li⁺ and Mg²⁺ and between Cl⁻ and SO₄²⁻, respectively. The electro-stripping mechanism when monovalent ion migrating across the membranes probably magnitude the Li⁺ selectivity, which is higher than the other reported values in the literature for membrane processes, and the purity of the final LiCl product is greater than battery grade (99.95%). The proposed process can potentially be applied in efficient ion fractionation and special separations.