Performance Of Forward Osmosis Membranes Research Articles

Controlling amine monomers via UiO-66-NH2 defect sites to enhance forward osmosis membrane performance for lithium recovery

The excessive thickness of the separation layer and the presence of cracks cause low water flux and poor lithium recovery in conventional forward osmosis (FO) membranes. According to the influence of the diffusion behavior of amine monomers in interfacial polymerization, the use of an interlayer optimizes the separation layer structure of traditional thin-film composite FO membrane. However, it is difficult to accurately control the separation layer structure by simply adjusting the amount of the interlayer material loaded. Herein, FO membranes with defect-containing metal–organic framework (MOF) interlayers were constructed. By adjusting the concentrations of competitive ligands, the MOFs showed different degrees of linker loss, which exposed the metal ions in the MOFs to different extents. The defective sites of the constructed MOFs increased the interaction between the interlayer and m-phenylenediamine (MPD), and density functional theory (DFT) simulations also revealed an increase in the binding energy of the two materials. Therefore, MPD attachment and diffusion were controlled by changing the proportion of defects in the MOFs, thereby finely regulating the separation layer structure. Additionally, tannic acid (TA) was predeposited to improve the stability of the interlayer. The prepared membrane exhibited water fluxes of 33.84 and 65.81 LMH and reverse salt fluxes of 0.58 and 2.38 gMH in the active layer facing feed solution (AL-FS) and active layer facing draw solution (AL-DS) modes, respectively. Excellent lithium ion recovery and fouling resistance was also demonstrated in battery wastewater treatment.

Effects of substrate (track-etched filter) properties on the performance of forward osmosis membranes

Highly permeable membranes can improve the validity of water treatment using forward osmosis (FO) membranes. This study aims to identify the effects of substrate (track-etched (TE) filter) properties on the permeability of FO membranes. The polyamide active layer properties of three types of TE filters with similarly-sized pore diameters (0.2 μm) were observed to be equivalent regardless of the substrate porosity (13.7%–15.8 %) and substrate thickness (10–25 μm). Under the same fabrication protocol using 1.5 wt% m-phenylenediamine (MPD) solution with 0.25 wt% sodium dodecyl sulfate (SDS) addition, the increased porosity of the TE filter increased water flux. This suggested that further reduction in thickness and increase in porosity can enhance the water flux. The addition of SDS to an MPD solution was crucial in maximizing the water flux of TE filter-based FO membranes, and the other approaches (no surfactant addition or the addition of Tween80 or hexadecyltrimethylammonium bromide) produced lower water flux. The optimized fabrication protocol presented the highest water flux of 43 L/m2h and reverse salt flux of 10 g/m2h with the draw (1.0 M NaCl) and feed (pure water) solutions. This study determined the best approach for forming a highly permeable PA active layer on TE filters.

Improving antifouling performance of FO membrane by surface immobilization of silver nanoparticles based on a tannic acid: diethylenetriamine precursor layer for municipal wastewater treatment.

In this study, a facile method for multifunctional surface modification on forward osmosis (FO) membrane was constructed by surface immobilization of AgNPs based on tannic acid (TA)/diethylenetriamine (DETA) precursor layer. The cellulose triacetate (CTA) FO membranes modified by TA and DETA with different co-deposition time (6 h, 12 h, 24 h) were investigated. Results indicated that the TA/DETA (24)-Ag CTA membrane with a TA/DETA co-deposition time of 24 h was identified to be optimal, which attained more hydrophilic. And it had the bacterial mortality of Escherichia coli and Staphylococcus aureus reaching 98.23% and 99.83% respectively and possessed excellent physical and chemical binding stability. Meanwhile, the coating layer resulted in the antifouling ability without damaging the membrane intrinsic transport characteristics. As for synthetic municipal wastewater treatment, the water flux of CTA FO membrane decreased approximately 49% of the initial flux after running for 14 days. In contrast, the flux decline rate of TA/DETA (24)-Ag CTA membrane was about 37%. Furthermore, less foulant deposition and higher recovery rate of water flux was observed for TA/DETA (24)-Ag CTA membrane, implying that the modified membrane effectively alleviated membrane fouling and processed a lower flux decline during municipal wastewater treatment. It was attributed to the enhanced surface hydrophilicity and antibacterial property of the coating layer, which improved antifouling property.

Predicting forward osmosis performance with synthesized polyamide-based membrane: An integrated machine learning (MATLAB and ANN) and economic analysis framework

Forward Osmosis (FO) has emerged as a highly promising membrane-based water treatment process owing to its intrinsic advantages, such as low energy requirements and the potential for high water recovery. The lab-prepared highly efficient thin film composite (TFC) FO membranes that were used in this research work. The resultant polyamide-based FO membrane showed exceptional performance, notably achieving a high-water flux of 60.94 ± 3.5 L/m2.h and a constrained solute flux of 1.52 ± 0.08 g/m2.h. Machine learning methodologies are strategically employed in this study to construct predictive models for FO membrane performance. Notably, the accuracy of the van't Hoff equation's linear assumption is significantly enhanced by introducing an osmotic pressure calculation based on water activity, considering the nuanced effects of external and internal concentration polarization. The research employs MATLAB software alongside an artificial neural network (ANN) to develop predictive models. MATLAB facilitates the creation of a comprehensive theoretical model, offering insights into forecasting water flux through FO membranes by systematically analyzing diverse membrane parameters and their impact on performance. Concurrently, the ANN model was employed to predict the permeate flux for the laboratory-scale FO membrane system, utilizing the input parameters within the network's training range (R2 > 0.91). An economic assessment is also conducted to estimate the projected membrane cost, a pivotal determinant of system viability. Collectively, these investigations yield valuable insights into the intricacies of FO membrane design and optimization, elucidating their performance dynamics in water treatment and allied applications. This research significantly contributes to the ongoing quest to develop more efficient and precise membrane processes.

Improving surface characteristics and operational parameters of polyvinyl chloride ultrafiltration membranes: How to manipulate the performance of thin film composite forward osmosis membranes?

The environmental and economic costs are pivotal aspects that should be considered before the commercialization of any membrane separation-based process. Particularly, realizing this goal relies entirely on the key role played by fabrication and operational parameters. Herein, we introduced a systematic investigation for constructing thin-film composite (TFC) - forward osmosis (FO) membranes for direct fertigation applications. To the best of our knowledge, PVC membrane was rarely used as a porous top surface substrate for TFC-FO membranes. The PVC substrate porous structure and polyamide (PA) active layer were manipulated by variating their concentrations and reaction time to optimize the FO membrane performance. All necessary characterization tools were employed to visualize the fabricated TFC membrane's surface characteristics. The influence of feed solution concentration, membrane orientation, flow rate, and draw solutes on the FO work was also methodically tested. Results demonstrated that the porous structure-substrate membrane host polymer content had imparted a significant role in tailoring the TFC-FO performance concerning permeability and back-solute flux. The water flux was improved by 44.3 % with decreasing of the PVC amount, whereas water flux was improved by 48.13 % with decreasing of the M-phenylenediamine monomer (MPD) content from 3 to 1 wt% at constant tri-mesoylchloride monomer (TMC) content of 0.1 wt% in IP reaction conditions of a thin film. This was gone hand in hand with optimal operational conditions harnessed for optimizing the FO process.

Towards enhanced performance of fertilizer-drawn forward osmosis process coupled with sludge thickening using a thin-film nanocomposite membrane interlayered with Mxene scaffolded alginate hydrogel

Forward osmosis (FO) offers the potential for sustainable wastewater reuse and enhance water resource sustainability and resiliency. However, low performance of FO membranes due to the high structural parameter and poor fouling resistance limits their widespread implementation. Structural parameter minimization of substrates and modulation of the surface structures of polyamide nanofilms are crucial to achieve enhanced FO performance. Herein, a novel thin-film nanocomposite (TFN) FO membrane supported with Mxene scaffolded alginate hydrogel interlayer is fabricated. It is found that the incorporation of the hydrophilic and high surface energy alginate hydrogel@Mxene interlayer sandwiched between polyamide nanofilms and microporous substrate minimizes the structural parameter by creating abundant tortuous paths leading to minimized internal concentration polarization. Meanwhile, the nanoconfinement effect induced by the interlayer enabled the formation of lumpy network of bubble wrap-like textured polyamide structures on the membranes. Subsequently, the resulting membranes exhibited enhanced water flux of up to 45.6 LMH in PRO mode using 1.0 M NaCl as the draw solution, while the lower surface roughness bestowed the membranes with the minimal fouling propensity which resulted in more than 80% of the water recovery. Additionally, the integration of the fertilizer-drawn forward osmosis process with sludge thickening successfully enabled the dilution of a 2 M KCl fertilizer solution by 2.4 times after 12 h operation, while simultaneously concentrating the sludge from the MLSS of 2000 mg L−1 to 5183 mg L−1. This work provides important insightful concepts to inspire the development of advanced TFN-FO membranes with good overall performance suitable for sustainable water reuse using osmotically driven membrane processes.

Comparative mathematical and data-driven models for simulating the performance of forward osmosis membrane under different draw solutions

Mathematical models have frequently been used to simulate system performance, including forward osmosis (FO)-related processes. More recently, Industry 4.0 has increased in importance, and artificial intelligence (AI) technology has proven to be effective at assisting decision-making across a range of industries, including membrane processes. This study, for the first time, proposes a comparison of the accuracy of predictions for water permeability under various types of draw solutions using conventional models and AI-based models. The results showed that the AI-based models, including artificial neural networks (NN) (2 layers; 10 neurons) and adaptive neuro-fuzzy inference system (NFIS) (with grid partition; membership functions = 5) performed significantly better than the conventional mathematical intermediate blocking (CIB) model, with the coefficient values (R) of 0.974, 0.994, and 0.963, respectively. The corresponding errors of these simulations were 0.04, 0.70, and 0.97 LMH, indicating that the AI technique was better suited than the mathematical CIB model for simulating FO-related system performance. Additionally, using AI to forecast system performance is timely (i.e., considerably quicker than developing a sophisticated mathematical model) and cost-effective (i.e., reducing the expense for analysis of environmental factors for CIB model construction). The authors also successfully constructed an application for end-users for better and simpler experiences with modeling and simulation, even for those with varying knowledge in the field.

Synergistic effects of microplastics and organic foulants on the performance of forward osmosis membranes

Microplastics (MPs) are emerging contaminants that are abundantly present in the influent and effluent of wastewater treatment plants (WWTPs). Forward osmosis (FO) is an advanced treatment technology with potential applications in WWTPs. The presence of MPs in WWTP effluents can contribute to FO fouling and performance deterioration. This study focuses on FO membrane fouling by MPs of different sizes, and the interactional impacts of MPs and Humic acid (HA) (as the most common organic foulant in WWTPs) on FO membrane performance. The synergistic effect of combined MPs and HA fouling is shown to cause higher flux decline for FO membranes than that of HA or MPs alone. Reverse salt flux increased in the presence of MPs, and decreased when HA was present. Further, full flux recovery was obtained for all fouled membranes after hydraulic cleaning. This indicates the efficiency of FO systems for treating wastewater with high fouling potential. This study highlights the necessity of considering MPs in studying fouling behaviour, and for mitigation strategies of membranes used in WWT. The fundamentals created here can be further extended to other membrane-assisted separation processes.

Improved Forward Osmosis Performance of Thin Film Composite Membranes with Graphene Quantum Dots Derived from Eucalyptus Tree Leaves.

The major challenges in forward osmosis (FO) are low water flux, high specific reverse solute flux (SRSF), and membrane fouling. The present work addresses these problems by the incorporation of graphene quantum dots (GQDs) in the polyamide (PA) layer of thin-film composite (TFC) membranes, as well as by using an innovative polyethersulfone nanofiber support for the TFC membrane. The GQDs were prepared from eucalyptus leaves using a facile hydrothermal method that requires only deionized water, without the need for any organic solvents or reducing agents. The nanofiber support of the TFC membranes was prepared using solution blow spinning (SBS). The polyamide layer with GQDs was deposited on top of the nanofiber support through interfacial polymerization. This is the first study that reports the fouling resistance of the SBS-nanofiber-supported TFC membranes. The effect of various GQD loadings on the TFC FO membrane performance, its long-term FO testing, cleaning efficiency, and organic fouling resistance were analyzed. It was noted that the FO separation performance of the TFC membranes was improved with the incorporation of 0.05 wt.% GQDs. This study confirmed that the newly developed thin-film nanocomposite membranes demonstrated increased water flux and salt rejection, reduced SRSF, and good antifouling performance in the FO process.

UiO-66-NH2 nanocomposites incorporated cellulose acetate for forward osmosis membranes of high desalination performance

ABSTRACT In this paper, the hydrophilic UiO-66-NH2 nanomaterial was synthesized by the solvent-thermal method and characterized. Then, UiO-66-NH2 was introduced into the casting membrane solution of cellulose acetate (CA) forward osmosis (FO) membrane, and CA/UiO-66-NH2 forward osmosis membrane was prepared by the phase inversion method. The optimum preparation conditions of CA/UiO-66-NH2 mixed matrix membranes were determined as follows: the content of UiO-66-NH2 was 0.4 wt%, the coagulation bath temperature was 35°C, the mixing temperature was 50°C and the heat treatment temperature was 50°C. FTIR, SEM, water contact angle and AFM were carried out on CA/UiO-66-NH2 forward osmosis membrane prepared under the best preparation conditions. Compared to the CA forward osmosis membrane, the permeability and selectivity of the CA/UiO-66-NH2 membrane were improved. The water flux and reverse salt flux of the CA/UiO-66-NH2 forward osmosis membrane reached 52.32 L/(m2·h) and 2.43 g/(m2·h), respectively. The permeability selectivity of CA membranes and CA/UiO-66-NH2 membranes did not change much during 180 min, indicating that the two membranes had good long-term stability. This study shows a potential advantage of UiO-66-NH2 as additives for improvement in the desalination performance of forward osmosis membranes.

Synergistic effect of highly porous microstructured support and co-solvent assisted interfacial polymerization on the performance of thin-film composite FO membranes

Internal concentration polarization (ICP) in a dense support layer is one of the main reasons holding back forward osmosis (FO) process. In this regard, a highly porous microstructured support (HPμS) featuring a quasi-sponge-free sublayer pore structure can be considered a suitable alternative to develop high-performance FO membranes. However, it has not been tested for its effects on FO. This study demonstrates that a TFC membrane prepared using the HPμS works out for FO by inducing 3.35 times higher water flux without compromising a reverse salt flux (Js) compared to a control TFC membrane prepared without support adjustment. The performance improvement could be achieved by HPμS's almost no sponge-like region and lateral walls, which were desirable to minimize ICP. Furthermore, we verified that it is possible to leverage co-solvent assisted interfacial polymerization (CAIP) to further improve FO membrane performances by creating a more permeable active layer. The in-house TFC membrane optimized by the HPμS and CAIP displayed 5.3 times higher FO water flux than the control membrane, while keeping comparable Js. We expect that this research could contribute to kicking the FO membrane performance up a notch by providing a practical example of simultaneous optimization of both support and active layers.

Preparation and characterization of double-skinned FO membranes: Comparative performance between nanofiber and phase conversion membranes as supporting layers

To address the internal concentration polarization (ICP) effect and membrane fouling problems of forward osmosis technology in pressure retarded osmosis (PRO) mode, another highly selective polyamide (PA) layer was introduced on the other side of the single-skinned forward osmosis (FO) membrane. Recently, a new symmetrical nanofiber support layer has shown excellent performance. For better proof, the nanofiber support layer and the phase inversion support layer were prepared separately in this study, respectively, and two double-skinned FO membranes were obtained via interfacial polymerization. By comparing various surface physicochemical properties of the nanofiber support layer and the phase inversion support layer, it can be seen that the double-skinned PA layer formed on the surface of the nanofiber support layer had better performance. The nanofiber double-skinned FO membrane showed water flux of 19.99 LMH when using 2 M NaCl and DI water as the draw and feed solution, much higher than that of the phase inversion double-skinned FO membrane. Furthermore, the anti-fouling performance of the nanofiber double-skinned FO membrane was also better than that of the phase inversion double-skinned FO membrane. This study pointed out a new direction for a double-skinned FO membrane with high permeability selectivity and provided a promising method for anti-membrane fouling.

Silicene nanosheets as support fillers for thin film composite forward osmosis membranes

Development of membranes with enhanced separation and transport properties remains crucial for the advancement of forward osmosis (FO). Herein, a novel thin film composite (TFC) FO membrane with silicene-loaded polysulfone support (SN) is reported. Silicene loading was varied to obtain different SNs grown with polyamide (PA) layers to afford TFC-SN FO membranes. Characterization results reveal that optimal silicene loading (0.25 wt%) produced the most porous and most hydrophilic SN0.25 with finger-like pore structures. Low silicene loading showed minimal impact, whereas, excessive addition resulted in aggregation which diminished its effect in SN. Meanwhile, silicene had no influence on PA layer formation as all TFC-SNs registered similar solute permeability coefficient B = 0.14–0.16 LMH. On the other hand, TFC-SN0.25 achieved the highest water permeability coefficient A = 1.56 LMH bar−1 attributable to the favorable properties of SN0.25. TFC-SN0.25 also exhibited the lowest structural parameter S = 334 μm, which explains its superior FO performance relative to other TFC-SNs. Results from FO runs indicate that internal concentration polarization was reduced by 27.5–33% in TFC-SN0.25 compared with the control (TFC-SN0). FO runs in simulated low salinity water and seawater feed highlight the potential of TFC-SN0.25 for desalination. The developed TFC-SN0.25 can be repeatedly used and deliver consistent Jv values. Overall findings demonstrate the benefits of silicene for improved performance of TFC FO membranes.

Effects of Different Draw Solutions on Biogas Slurry Concentration in Forward Osmosis Membrane: Performance and Membrane Fouling.

Biogas slurry poses a severe challenge to the sustainable management of livestock farms. The technology of the forward osmosis (FO) membrane has a good application prospect in the field of biogas slurry concentration. Further research is needed to verify the effects of different draw solutions on FO membranes in biogas slurry treatment and the related membrane fouling characteristics. In this study, three different draw solutions were selected to evaluate the performance of FO membranes for biogas slurry concentration. Membrane fouling was investigated by characterization after FO membrane treatment to identify fouling contaminants. The result showed that FO membrane treatment can realize the concentration of biogas slurry and MgCl2 as the draw solution has the best effect on the concentration of biogas slurry. The different draw solutions all contributed to the efficient retention of most organics and TP while each treatment was ineffective at retaining nitrogen. The cake layer that appeared after the biogas slurry was concentrated covered the surface of the FO membrane. Some functional groups were detected on the surface after membrane fouling, such as C–O and C=C. Moreover, the C element accounts for 57% of the main components of the cake layer after the membrane fouling. Membrane fouling is caused by both organic fouling and inorganic fouling, of which organic fouling is the main reason. This study provides a technical reference for the high-value utilization of biogas slurry.

MIL-53(Fe)@γ-Al2O3 nanocomposites incorporated cellulose acetate for forward osmosis membranes of high desalination performance

Forward osmosis (FO) membrane is a promising membrane technique. However, its application in desalination is limited. Thus, we synthesized MIL-53(Fe)@γ-Al2O3 via solvent-thermal method to fabricate MIL-53(Fe)@γ-Al2O3/cellulose acetate (CA) composite membranes of high desalination performance. MIL-53(Fe)@γ-Al2O3 and MIL-53(Fe) particles were studied using XRD, FITR, SEM, N2 adsorption-desorption isotherms, and AFM. The structural features of MIL-53(Fe)@γ-Al2O3/CA membrane and MIL-53(Fe)/CA membrane were analyzed using SEM, AFM and water contact angle. The reverse salt flux and water flux of the MIL-53(Fe)@γ-Al2O3/CA membrane reached 1.78 g m-2 h-1 and 37.1 L m-2 h-1, respectively, when the deionized water and 1 M NaCl solution were the feed solution and traction solution, respectively. Compared to the MIL-53(Fe)/CA membrane, the MIL-53(Fe)@γ-Al2O3/CA membrane demonstrated better perviousness and selectivity properties of the membrane. This study shows a potential advantage of MOF composites as additives for improvement in the desalination performance of forward osmosis membranes.

Comparative Mathematical and Data-Driven Models for Simulating the Performance of Forward Osmosis Membrane Under Various Types of Draw Solutions

Comparative Mathematical and Data-Driven Models for Simulating the Performance of Forward Osmosis Membrane Under Various Types of Draw Solutions

Synergistic Effects of Microplastics and Organic Foulants on the Performance of Forward Osmosis Membranes ​

Synergistic Effects of Microplastics and Organic Foulants on the Performance of Forward Osmosis Membranes ​

Insights into the impact of polydopamine modification on permeability and anti-fouling performance of forward osmosis membrane

Forward osmosis (FO) has drawn wide attention as a promising method to address world-wide water crisis due to the advantages of low-energy consumption and easy separation operation. Unfortunately, the trade-off between permeability and selectivity as well as membrane fouling hindered the application of forward osmosis. Surface modification is a feasible method to address these issues. However, there is a lack of systematic evaluation about the effect of modification position on FO performance due to the asymmetric structure of thin film composite (TFC) FO membrane. To provide new insights into the design of FO membrane with satisfied permeability and fouling resistance, novel TFC FO membranes were fabricated by introducing polydopamine (PDA) on the support layer (TFC-I) or active layer (TFC-S), respectively. The surface morphology, chemical composition and wettability of the fabricated membrane were studied. It was found that the surface wettability of the modified membrane was improved greatly compared to pristine TFC membrane (TFC-C). Moreover, TFC-S membrane displayed a rougher surface than that of TFC-I membrane. As a result, a superior TFC-S membrane with a water flux of 60.95 ± 3.15 L m−2h−1 in AL-DS mode was obtained, which was 72.61% and 17.87% higher than that of TFC-C and TFC-I membrane, respectively. In addition, the TFC-S membrane also presented an excellent fouling resistance and membrane regeneration performance during the three organic fouling cycle experiments. The results indicated that the introduction of PDA as a surface coating for TFC membranes modification guaranteed the high-performance and fouling resistance. Especially, the PDA coating on the support layer surface resulted in an enhancement in permeability, while both the permeability and anti-fouling performance were significantly improved with the PDA coating on the polyamide active layer surface. This study provides new insights into the development of modification TFC-FO membranes for practical applications in water treatment.

Developing a Thin Film Composite Membrane with Hydrophilic Sulfonated Substrate on Nonwoven Backing Fabric Support for Forward Osmosis.

This study describes the fabrication of sulfonated polyethersulfone (SPES) as a super-hydrophilic substrate for developing a composite forward osmosis (FO) membrane on a nonwoven backing fabric support. SPES was prepared through an indirect sulfonation procedure and then blended with PES at a certain ratio. Applying SPES as the substrate affected membrane properties, such as porosity, total thickness, morphology, and hydrophilicity. The PES-based FO membrane with a finger-like structure had lower performance in comparison with the SPES based FO membrane having a sponge-like structure. The finger-like morphology changed to a sponge-like morphology with the increase in the SPES concentration. The FO membrane based on a more hydrophilic substrate via sulfonation had a sponge morphology and showed better water flux results. Water flux of 26.1 L m−2 h−1 and specific reverse solute flux of 0.66 g L−1 were attained at a SPES blend ratio of 50 wt % when 3 M NaCl was used as the draw solution and DI water as feed solution under the FO mode. This work offers significant insights into understanding the factors affecting FO membrane performance, such as porosity and functionality.

Inorganic scaling in the treatment of shale gas wastewater by fertilizer drawn forward osmosis process

In this study, fertilizer drawn forward osmosis (FDFO) process was applied for the treatment of shale gas wastewater. The forward osmosis (FO) experiments with simulated shale gas wastewater and real shale gas wastewater were carried out, respectively. The effects of reverse salt diffusion on the inorganic fouling to the membrane surface was systematically investigated. Two commercial FO membranes were selected and the optimized operating conditions were evaluated. It was found that calcium sulfate scaling can be alleviated by optimizing the operating parameters, including increasing flow rate and decreasing temperature. Furthermore, the Aquaporin FO membrane, which has lower reverse salt flux and less surface charge potential, exhibited lower fouling tendency. Under the optimal operating conditions, the effects of reverse salt diffusion on the barium sulfate scaling were also analyzed. The presence of calcium ions can alleviate barium sulfate scaling, while sodium chloride will aggravate the barium sulfate scaling. In addition, the scaling behavior of real shale gas wastewater was further explored. Inorganic scaling phenomenon seriously affected the FO membrane performance and lower pH had beneficial effect on recycling the real shale gas wastewater. The present study provided both theoretical fundamentals and industry applicable practices for implementing FO technology in the treatment and resource recovery of shale gas wastewater.