Reverse Osmosis Experiments Research Articles

Investigation of the impact of sodium dodecylbenzene sulfonate modification on the wettability of coking coal

ABSTRACT To investigate the impact of sodium dodecylbenzene sulfonate (SDBS) modification on coking coal’s wettability, our research focuses on coking coal and uses SDBS as the surfactant in the experiment. The surface tension, scanning electron microscope, FTIR, contact angle measurement, and reverse osmosis experiment are employed to measure the microscopic characteristics and wettability of raw coking coal, water-soaked coal, and coal soaked in 0.0005%, 0.005%, and 0.05% SDBS solutions. Finally, the dust reduction efficiency was determined by spray dust reduction experiments. We analyzed the effect of varying mass fractions of SDBS on coking coal’s wettability. The findings indicate that the surface of coal samples soaked in water and SDBS solution become rough. Adding clean water and SDBS solution improves the coal samples’ wettability. Among various coal samples soaked in different solutions, the one treated with 0.005% SDBS solution exhibits the smallest contact angle, significantly higher moisture absorption, and the most pronounced wetting effect. Soaking the coal samples in 0.005% SDBS solution can achieve the highest dust reduction efficiency. In summary, soaking the coal samples in no matter clean water or SDBS solution can enhance the wettability of coal dust, while soaking in 0.005% SDBS solution has a better effect.

Antiscalants for mitigating silica scaling in membrane desalination: Effects of molecular structure and membrane process

Silica scaling is a major type of mineral scaling that significantly constrains the performance and efficiency of membrane desalination. While antiscalants have been commonly used to control mineral scaling formed via crystallization, there is a lack of antiscalants for silica scaling due to its unique formation mechanism of polymerization. In this study, we performed a systematic study that investigated and compared antiscalants with different functional groups and molecular weights for mitigating silica scaling in membrane distillation (MD) and reverse osmosis (RO). The efficiencies of these antiscalants were tested in both static experiments (for hindering silicic acid polymerization) as well as crossflow, dynamic MD and RO experiments (for reducing water flux decline). Our results show that antiscalants enriched with strong H-accepters and H-donors were both able to hinder silicic acid polymerization efficiently in static experiments, with their antiscaling performance being a function of both molecular functionality and weight. Although poly(ethylene glycol) (PEG) with abundant H-accepters exhibited high antiscaling efficiencies during static experiments, it displayed limited performance of mitigating silica scaling during MD and RO. Poly (ethylene glycol) diamine (PEGD), which has a PEG backbone but is terminated by two amino groups, was efficient to both hinder silicic acid polymerization and reduce water flux decline in MD and RO. Antiscalants enriched with H-donors, such as poly(ethylenimine) (PEI) and poly(amidoamine) (PAMAM), were effective of extending the water recovery of MD but conversely facilitated water flux decline of RO in the presence of supersaturated silica. Further analyses of silica scales formed on the membrane surfaces confirmed that the antiscalants interacted with silica via hydrogen bonding and showed that the presence of antiscalants governed the silica morphology. Our work indicates that discrepancy in antiscalant efficiency exists between static experiments and dynamic membrane filtration as well as between different membrane processes associated with silica scaling, providing valuable insights on the design principle and mechanisms of antiscalants tailored to silica scaling.

Novel method for accurately estimating membrane transport properties and mass transfer coefficients in reverse osmosis

We present a simple and robust method to simultaneously characterize the water and salt permeability (A, B) of reverse osmosis (RO) membranes and mass transfer coefficient (k) in membrane modules. The proposed methodology comprises a set of RO experiments performed at different operating pressures or stages. The measured water and salt fluxes in each stage are simultaneously fitted to the RO transport equations by performing a non-linear regression, using A, B, and k as regression parameters. We first perform a systematic accuracy analysis of the proposed method across the full operational range of RO. The assessment shows that the method accuracy is substantially higher than current methods and increases with number of experimental stages and driving forces. This assessment is used to inform the design of an experimental protocol that minimizes errors in estimated A, B, and k. We then evaluate two commercial RO membranes following the new protocol. For both membranes, A and B parameters decrease by 17% and 15% from the dilute solution to seawater concentrations, whereas the k parameter remains constant. Our study demonstrates that the proposed method, informed by data-driven experimental designs, provides a new approach for accurately characterizing transport phenomenon in membrane processes with feeds of less than 100 g/L total dissolved solids.

Significance of Co-ion Partitioning in Salt Transport through Polyamide Reverse Osmosis Membranes.

Salt permeability of polyamide reverse osmosis (RO) membranes has been shown to increase with increasing feed salt concentration. The dependence of salt permeability on salt concentration has been attributed to the variation of salt partitioning with feed salt concentration. However, studies using various analytical techniques revealed that the salt (total ion) partitioning coefficient decreases with increasing salt concentration, in marked contrast to the observed increase in salt permeability. Herein, we thoroughly investigate the dependence of total ion and co-ion partitioning coefficients on salt concentration and solution pH. The salt partitioning is measured using a quartz crystal microbalance (QCM), while the co-ion partitioning is calculated from the measured salt partitioning using a modified Donnan theory. Our results demonstrate that the co-ion and total ion partitioning behave entirely differently with increasing salt concentrations. Specifically, the co-ion partitioning increased fourfold, while total ion partitioning decreased by 60% as the salt (NaCl) concentration increased from 100 to 800 mM. The increase in co-ion partitioning with increasing salt concentration is in accordance with the increasing trend of salt permeability in RO experiments. We further show that the dependence of salt and co-ion partitioning on salt concentration is much more pronounced at a higher solution pH. The good co-ion exclusion (GCE) model─derived from the solution-friction model─is used to calculate the salt permeability based on the co-ion partitioning coefficients. Our results show that the GCE model predicts the salt permeabilities in RO experiments relatively well, indicating that co-ion partitioning, not salt partitioning, governs salt transport through RO membranes. Our study provides an in-depth understanding of ion partitioning in polyamide RO membranes and its relationship with salt transport.

Development of robust and high-performance polysilsesquioxane reverse osmosis membranes modified by SiO2 nanoparticles for water desalination

Robust and highly water permeable organically bridged polysilsesquioxane (PSQ) reverse osmosis (RO) membranes were prepared by introducing SiO2 nanoparticles into bis[3-(triethoxysilyl)propyl]amine (BTESPA)-based RO membrane by the sol–gel process. Nitrogen adsorption/desorption isotherm measurements revealed that BET surface areas are significantly increased by introduction of SiO2 nanoparticles. RO experiments using a 2000 ppm NaCl aqueous solution indicate that the addition of SiO2 nanoparticles improves membrane RO performance; water permeability was 1.2 × 10-12 m3/m2sPa and salt rejection was approximately 98%. It was also found that these membranes exhibited high thermal stability, i.e., after heat treatment at 95 ℃ for 180 min, the membranes showed a salt rejection decrease of less than 2.5%. In addition, the membranes manifested favorable resistance to chlorine exposure, namely, salt rejection decrease was less than 2% after 10,000 ppm⋅h NaOCl exposure.

Removal of pesticides from secondary treated urban wastewater by reverse osmosis.

The residues of pesticides that reach water resources from agricultural activities in several ways contaminate drinking water resources and threaten aquatic life. This study aimed to investigate the performance of three reverse osmosis (RO) membranes (BW30-LE, SW30-XLE, and GE-AD) in rejecting four different pesticides (tributyl phosphate, flutriafol, dicofol, and irgarol) from secondary treated urban wastewater and also to elucidate the mechanisms underlying the rejection of these pesticides. RO experiments were conducted using pesticide-spiked wastewater samples under 10 and 20bar transmembrane pressures (TMP) and membrane performances were evaluated. Overall, all the membranes tested exhibited over 95% rejection performances for all pesticides at both TMPs. The highest rejections for tributyl phosphate (99.0%) and irgarol (98.3%) were obtained with the BW30-LE membrane, while for flutriafol (99.9%) and dicofol (99.1%) with the GE-AD membrane. The increase in TMP from 10 to 20bar did not significantly affect the rejections of all pesticides. The rejection performances of RO membranes were found to be governed by projection area as well as molecular weight and hydrophobicity/hydrophilicity of pesticides. Among the membranes tested, the SW30-XLE membrane was the most prone to fouling due to the higher roughness.

Synthetic subnanochannels in porous aromatic frameworks accelerate selective water permeation in membrane desalination

Creation of freeways in a membrane accelerates water transport for efficient desalination; however, the synthesis of target membrane materials is very challenging. In the present study, the molecular-design strategy is developed for the synthesis of porous aromatic framework (PAF) membranes with rigid and open networks to regulate water transport. Nitrile-based monomers in triangle shape are designed for the construction of PAF-98 and its sister frameworks, and these PAF membranes are formed through trifluoromethan-esulfonic acid catalysis. The rigidity and geometry of the monomers endow PAFs with unique structures of connected pores with edging size (4.5–6.7 Å) between water (2.8 Å) and hydrated sodium molecules (7.2 Å), enabling effective differentiation of water and salt. The fabricated membranes with high flexibility and continuity are ideal for water desalination, and reverse osmosis experiments demonstrate that the three PAF membranes are selective for permeation of water molecules over hydrated sodium cations. Unprecedented water flux of 547.1 L m−2 h−1 and high rejection degree of 90% are obtained on a representative membrane of PAF-98-E; and the desalination performance is superior to currently available membrane materials. Furthermore, PAF-98-E membrane is capable of rejecting various cations with high efficiency in real seawater, holding great promise in practical water desalination application.

A Case Study of Calcium Carbonate Crystallization during Reverse Osmosis Water Desalination in Presence of Novel Fluorescent-Tagged Antiscalants.

Calcium carbonate scaling in reverse osmosis (RO) desalination process is studied in the presence of two novel fluorescent-tagged scale inhibitors 1,8-naphthalimide-tagged polyacrylate (PAA-F1) and 1-hydroxy-7-(6-methoxy-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)heptane-1,1-diyl-bis(phosphonic acid) (HEDP-F) by fluorescent microscopy (FM) and scanning electron microscopy (SEM). Both antiscalants diminished the mean size of calcite crystals relative to the blank experiment. The behavior and localization of HEDP-F and PAA-F1 during calcite scale formation on membrane surface was found to be significantly different from the distribution in similar RO experiments with gypsum, reported earlier. In the former case, both antiscalants are concentrated exactly on the surface of calcium carbonate crystals, while in the latter one they form their own phases (Ca-HEDP-F and Ca-PAA-F1) and are not detected on gypsum scale. The difference is interpreted in terms of interplay between background calcium concentration and sparingly soluble calcium salts’ solubility. HEDP-F reveals slightly higher efficiency than PAA-F1 against calcite scale formation, while PAA-F exhibits a higher ability to change calcite morphology. It is demonstrated that there is a lack of correlation between antiscaling efficacy and ability of antiscalant to change calcium carbonate morphology in a particular case study. An application of fluorescent-tagged antiscalants in RO experiments provides a unique possibility to track the scale inhibitor molecules’ localization during calcite scale formation. Fluorescent-tagged antiscalants are presumed to become a very powerful tool in membrane scaling inhibition studies.

Development of PSQ-RO membranes with high water permeability by copolymerization of bis[3-(triethoxysilyl)propyl]amine and triethoxy(3-glycidyloxypropyl)silane

Epoxy-based reverse osmosis (RO) membranes with an organically bridged polysilsesquioxane (PSQ) skeleton were prepared by a sol-gel process that involved the copolymerization of bis[3-(triethoxysilyl)propyl]amine (BTESPA) and triethoxy(3-glycidyloxypropyl)silane (TEGPS). RO experiments using 2000 ppm NaCl aqueous solution indicated that the use of epoxy-containing monomer TEGPS significantly improved performance, yielding water permeability of 1 × 10 −12 m 3 /m 2 sPa and salt rejection of 98%, approximately. This is likely because of the ring opening of the epoxy units, which leads to the formation of hydroxy (C–OH) groups during sol formation. Some C–OH groups underwent condensation with silanol to generate C–O–Si bonds in the gelation process. Immersion of the resultant membrane in water resulted in the hydrolysis of C–O–Si bonds to re-generate C–OH units. This increased membrane hydrophilicity and further improved permeability, although salt rejection slightly decreased. It was also found that membranes derived from TEGPS showed high resistance to chlorine and thermal stability. • New polysilsesquioxane (PSQ)-based RO membranes were prepared. • The use of epoxy-containing monomer significantly improved performance. • Water permeance of 9.6 × 10 −13 m 3 /m 2 sPa and salt rejection of 97.5% were obtained. • The present membranes showed high chlorine resistance and thermal stability.

Cleaning Strategies and Cost Modelling of Experimental Membrane-based Desalination Plants

In Project WASTEC, an experimental Reverse Osmosis (RO) desalination system was developed. It serves as a platform for testing new technologies. For this system, we solved two problems, which are described in this paper. Firstly, we developed and investigated strategies for scheduling chemical enhanced backwashing and chemical cleaning and secondly, due to the experimental nature of the project, several new technological developments with respect to materials and methods were integrated into the system and requires tools for evaluating the economic viability of the new technologies. In this task, the economics of membrane-based desalination will be investigated. Baseline systems of reverse osmosis and pretreatment systems (microfiltration and ultrafiltration) will be economically examined and compared for their investments and operational costs. Sensitivity of the different plant and membrane parameters to the cost will be studied. Results show that with respect to costs, for a 200m3/hr design capacity plant, a volume of water is produced by a MF process at a cost of $0.494 and at a cost of $0.486 by an ultrafiltration process microfiltration. The reverse osmosis process cannot be compared directly, but it required $ 0.49 / m3 for a plant with 56 m3/hour design capacity. The values are in line with the costs reported in literature for membrane-based filtration.

Experimental synthesis and performance comparison analysis of high-efficiency wetting enhancers for coal seam water injection

To improve the wettability effect of coal seam water injection, and reduce dust production from the source, this paper proposes the preparation of three kinds of high-efficiency wetting enhancers. In this study, 2-acrylamide-2-methylpropionic sulfonic acid and itaconic acid were introduced into the polymer chain of sodium alginate in different combinations. Anionic surfactant sodium dodecyl sulfate and nonionic surfactant aliphatic alcohol polyoxyethylene ether were added in different proportions to obtain three kinds of enhancers. The three kinds of enhancers have good viscosity and fluidity, and the optimal emulsifier additive is determined by a surface tension test. The hydrophilic hydroxyl, carboxyl or sulfonic groups of enhancers were obtained by a Fourier-transform infrared experiment, which was beneficial to water absorption. The contact effect of different solutions on coal block was studied by a scanning electron microscopy experiment. An energy dispersive spectrometry experiment proved that the solution was well dispersed. Through reverse osmosis experiment and contact angle analysis, the wettability of different solutions was compared, and the best enhancers was obtained. The molecular dynamics simulation was used to verify the relationship between them, and finally the mechanism of action was deduced. It was proved that AMPS-IA/SA+SDS/AEO had better wettability. Thus, AMPS-IA/SA+SDS/AEO is an ideal enhancer for coal seam water injection.

Geochemical modeling of chromium release in natural waters and treatment by RO/NF membrane processes

In this work, a geochemical approach was used as strong-scientific tool for pre-selection of suitable remediation systems to treat Cr-contaminated groundwaters. The geochemical characterization allowed to select Nanofiltration (NF) and Reverse Osmosis (RO) as suitable remediation processes, whereas through a new geochemical modeling, the evolution of water chemistry during the water-rock interaction was also studied. The new reaction path modelling was performed re-evaluating the role of Fe as main oxidant in the system and the analytic concentrations of relevant solutes, including Cr(VI), were reproduced. The spring with the highest Cr(VI) content was treated to lower its concentration below the threshold values. A laboratory-scale set-up was used to carry out both NF and RO experiments. The experiments were conducted on different commercial membranes varying the operating pressures. The results showed high Cr(VI) rejections (around 95%) for all tested membranes, leading to Cr(VI) concentrations below the threshold limits. The high flux, obtained already at lower operating pressures, combined with high selectivity towards Cr(VI) makes NF a favorable remediation option.

Minimizing the energy requirements for the production of maple syrup

Sucrose solutions were used as an analogue for maple sap in a series of reverse osmosis (RO) experiments. Based on the RO results, a model was developed to minimize the energy consumption and energy cost for concentrating maple sap at 2% sugar content up to 68% sugar content using both RO and evaporation processes. The RO model parameters were regressed from experiments performed on a bench scale RO membrane at an operating pressure of up to 50 bar and sucrose concentrations up to 33.6%. At the operating pressure of 50 bar, a cross flow velocity of 0.56 m s−1, and a temperature of 30 °C, the flux varied from 41 g m−2s−1 for deionized water down to 1.6 g m−2s−1 for a sucrose concentration of 33.6%. Upon simulation, it was found that an operating pressure of 50 bar was the most efficient to concentrate the sap to 36% to minimize energy consumption and 32% to minimize the energy cost. A sensitivity analysis showed that for 10% perturbations of process variables, the minimum energy and minimum energy cost would only deviate by up to a maximum of 6% and 7%, respectively. The maximum deviations where caused by the evaporator efficiency (minimum energy) and by reducing the cost of electrical energy (minimum energy cost).

Treatment of Tannery Wastewater with Vibratory Shear-Enhanced Processing Membrane Filtration

The performance of a vibratory shear-enhanced process (VSEP) combined with an appropriate membrane unit for the treatment of simulated or industrial tannery wastewaters was investigated. The fundamental operational and pollution parameters were evaluated, i.e., the membrane type, the applied vibration amplitude, as well as the removal rates (%) of tannins, chemical oxygen demand (COD), Ntotal, turbidity and color. Regarding the system’s treatment efficiency, specific emphasis was given towards the removal of organics (expressed as COD values), suspended solids (SS), conductivity (as an index of dissolved solids’ presence) and total nitrogen. The removal of organic matter in terms of COD exceeded 75% for all the examined cases. The quality of treated wastewater was affected not only by the membrane specific type (i.e., the respective pore diameters), but also by the applied vibration amplitude. Furthermore, an average 50% removal rate, regarding the aforementioned parameters, was observed both for the simulated and the industrial tannery wastewaters during the microfiltration (MF) experiments. That removal rate was further increased up to 85%, when ultrafiltration (UF) was applied, and up to 99% during the Reverse Osmosis (RO) experiments, considering the maximum applied vibration amplitude (31.75 mm).

High-flux thin film nanocomposite forward osmosis membrane incorporated with blue lemon polyoxometalate based open-framework

In this study a novel type of polyoxometalate based open-frameworks (POM-OFs) by using blue lemon (BL) as POM and tetrabutylammonium bromide (TBAB) as organic cationic coordinating agent successfully synthesized (BL.TBA-OFs) and incorporated in polyamide active layer via interfacial polymerization (IP) to fabricate hydrophilic and high water permeable thin-film nanocomposite (TFN) membranes. The prepared POM-OFs and TFN membranes were fully characterized using physicochemical techniques and the effect of POM-OFs incorporation on TFN membranes performance was investigated using reverse osmosis (RO) and forward osmosis (FO) experiments with regard to the water permeability, salt rejection, and selectivity. The enhancement in hydrophilicity of TFN membranes was confirmed by contact angle measurements, which attributed to the presence of superhydrophilic BL.POM. Water flux of the TFN-BL.TBA-4 membrane (with 400 ppm BL.TBA-OFs incorporation) increased from 18.1 to 28.6 LMH in FO mode, and 23.1 to 36.3 LMH in PRO mode, in comparison with unmodified TFC membrane. Enhancement in separation performance of the modified TFN membranes was attributed to the incorporation of nanopores BL.POM, which create short water pathways. By using sodium alginate as a foulant model the novel modified membrane showed better anti-fouling propensity than the TFC one. This report opens up a new modification route in the achieving of high efficient TFN membranes for FO process.

Diethylenedioxane-bridged microporous organosilica membrane for gas and water separation

Abstract A new dioxane-bridged alkoxysilane, 2,5-bis[2-(triethoxysilyl)ethyl]-1,4-dioxane (BTES-ED), was synthesized as a precursor of organically bridged silica membrane to investigate the effects of the 1,4-dioxane ring as a rigid and polar spacer. The monomer was polymerized by the sol-gel process to give the gels in film, powder, and membrane forms. Nitrogen adsorption measurement of the gel powder showed the type-I adsorption/desorption isotherm, suggesting that the gel possessed a microporous structure with pore size distribution ranging from approximately 0.8 to 1.6 nm. Reflecting microporosity, the membrane exhibited selective gas permeation properties (H2/SF6 permeance ratio = ca. 1900) based on molecular sieving effects. Reverse osmosis experiments were conducted using a 2000 ppm NaCl aqueous solution at an operation pressure of 1.0 MPa, revealing water desalination properties with the water permeance of 1.84 × 10−13 m3/m2·s·Pa and the NaCl rejection of 98.5%. These results are discussed in comparison with the results of other bridged silica membranes reported previously. The 2,5-diethylene-1,4-dioxane bridging unit is rigid and polar, thereby contributing to improving gas and water separation performance.

Preparation of bridged silica RO membranes from copolymerization of bis(triethoxysilyl)ethene/(hydroxymethyl)triethoxysilane. Effects of ethenylene-bridge enhancing water permeability

Copolymerization of bis(triethoxysilyl)ethene (BTESE2) and hydroxymethyl(triethoxy)silane (HMTES) was carried out to prepare new bridged silica membranes containing C-O-Si linkages. The membranes were examined for reverse osmosis (RO) to evaluate the water desalination properties. It was found that the hydrolysis of C–O–Si bonds occurred during the RO experiments to generate hydrophilic alcohol (C-OH) and silanol (Si-OH) units, thereby increasing the water permeability of the bridged silica membranes. Similar phenomenon was already reported for copolymer membranes prepared from bis(triethoxysilyl)ethane (BTESE1) and HMTES. However, the present membranes showed improved performance with higher water permeance by 4–14 times when compared to the previous BTESE1/HMTES-based membranes, although NaCl rejection was slightly lowered.

Double filtration as an effective system for removal of arsenate and arsenite from drinking water through reverse osmosis

Arsenic is one of the most dangerous inorganic pollutants present in drinking water, which is released both from certain human activities and naturally from the Earth’s crust. Arsenic is usually present in water in two oxidation states, as arsenite (As(III)) or arsenate (As(V)). Arsenate is usually easier to remove than arsenite. Therefore, the goal of this study is to check the potential use of double filtration for improving As(III) removal and to investigate if something happens with membrane, with arsenic solution, or both, after first filtration of As(III). With this objective, reverse osmosis experiments under specific conditions were conducted to get information about As(III) and As(V) removal efficiencies. Concretely, it was studied the effect of double filtration of arsenic on membrane surface and solution. Moreover, it was investigated the possible competitiveness between arsenic species as well as the occurrence of oxidation and aging effects. Results confirmed that double filtration is an efficient method to treat water that contains arsenite since filtration process might cause permanent changes on the physical structure of this specie, which led to an improvement of As(III) removal efficiency after 2nd filtration (removal efficiencies around 95%). Finally, total arsenic content of the treated water after 2nd filtration fulfilled with the maximum legislated level for drinking water (10 μg L−1).

Reverse Osmosis Shifts Chloramine Speciation Causing Re-Formation of NDMA during Potable Reuse of Wastewater.

UV-based advanced oxidation processes (AOPs) effectively degrade N-nitrosodimethylamine (NDMA) passing through reverse osmosis (RO) units within advanced treatment trains for the potable reuse of municipal wastewater. However, certain utilities have observed the re-formation of NDMA after the AOP from reactions between residual chloramines and NDMA precursors in the AOP product water. Using kinetic modeling and bench-scale RO experiments, we demonstrate that the low pH in the RO permeate (∼5.5) coupled with the effective rejection of NH4+ promotes conversion of the residual monochloramine (NH2Cl) in the permeate to dichloramine (NHCl2) via the reaction: 2 NH2Cl + H+ ↔ NHCl2 + NH4+. Dichloramine is the chloramine species known to react with NDMA precursors to form NDMA. After UV/AOP, utilities generally use lime or other techniques to increase the pH of the finished water to prevent distribution system corrosion. Modeling indicated that, while the increase in pH halts dichloramine formation, it converts amine-based NDMA precursors to their more reactive, neutral forms. With modeling, and experiments at both bench-scale and field-scale, we demonstrate that reducing the time interval between RO treatment and final pH adjustment can significantly reduce NDMA re-formation by minimizing the amount of dichloramine formed prior to reaching the final target pH.

Preparation of Bridged Polysilsesquioxane Membranes from Bis[3-(triethoxysilyl)propyl]amine for Water Desalination

Abstract Bridged polysilsesquioxane membranes containing amine units were prepared from bis[3-(triethoxysilyl)propyl]amine (BTESPA) by a sol-gel process, which consisted of sol formation by hydrolysis/condensation polymerization of BTESPA under neutral conditions and calcination of cast films of the sols on sulfonated polyethersulfone support membrane. A similar treatment of BTESPA, including sol formation under acidic conditions, afforded membrane with ammonium units. Thus-obtained porous BTESPA-based membrane was subjected to reverse osmosis (RO) experiments using 2000 ppm aqueous NaCl solution to examine its water desalination properties. Maximal liquid permeance (1.2 × 10−13 m3/m2·Pa·s) and NaCl rejection (97%) were achieved using the ammonium-containing membrane.