Forward Osmosis Membrane Process Research Articles

Forward osmosis membrane process: A review of temperature effects on system performance and membrane parameters from experimental studies

Forward osmosis (FO) offers a promising solution for concentration and material recovery, characterized by its low energy consumption and high separation efficiency. Temperature exerts a significant influence on FO, affecting permeation performance, membrane characteristics, and solution chemistry. The review article shows that increasing temperatures enhance forward permeate flux and solvent recovery by modifying mass transfer coefficients, membrane structure, and solution properties like osmotic pressure, diffusivity, and viscosity. This helps alleviate concentration polarization, a key challenge in FO applications. However, higher temperatures can exacerbate reverse solute flux, diminish solute rejection, and amplify membrane fouling, impacting operational efficiency and effluent quality. Studies involving thermoresponsive compounds or high-solute-content solutions yield conflicting results, further complicated by thermo-osmosis in scenarios with temperature gradients between solutions. In water and wastewater treatment, a huge quantity of solutions is treated, and temperature control is difficult. Managing solution temperatures through the utilization of waste hot streams or available heat sources can offer a viable strategy for enhancing system efficiency and mitigating the detrimental impacts of temperature fluctuations, while the solution volume should be effectively reduced before the treatment. A nuanced comprehension of temperature’s impacts is imperative for refining FO systems and addressing challenges across various industrial and environmental sectors.

Investigation of multi-stage forward osmosis membrane process for concentrating high-osmotic acrylamide solution

Investigation of multi-stage forward osmosis membrane process for concentrating high-osmotic acrylamide solution

Controlled architecture of multi-defense anti-fouling forward osmosis membrane for efficient shale gas wastewater treatment

Forward osmosis (FO) membrane process facilitates effective treatment of shale gas wastewater (SGW) due to its tolerance to high salinity and exceptional separation performance. However, serious membrane fouling remains a challenge regarding the complexity of realistic SGW. To address the fouling issues, controlled block copolymer architecture was constructed on the FO membrane surface to achieve combined effect of oil-resistance, self-regenerating, and fouling mitigation. In the modification process, zwitterionic polymer with strong hydrophilicity and fluoropolymers with low surface energy were successively grafted to the membrane active layer by atom transfer radical polymerization. The outermost fluoropolymer layer with low surface energy imparts the membrane with anti-oil and self-regenerating capabilities. Meanwhile, the strong hydration effect of the zwitterionic polymer ensures that nonspecific foulants breaking through the outermost defense are kept away from the membrane surface. According to the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the modified FO membrane exhibited a significantly higher total interaction energy (ΔGTOT) compared to the pristine membrane when exposed to various types of model foulants (bovine serum albumin, humic acid, sodium alginate, mineral oil). Furthermore, the advantage of having multiple defense mechanisms was further substantiated through dynamic filtration tests with realistic SGW. In comparison to the pristine TFC membrane, the modified membrane not only experienced a much smaller decrease in water flux (reduced by 52%) during fouling but also an exceptional flux recovery after cleaning (∼97%). These findings underscore that the modified FO membranes greatly mitigated membrane fouling associated with SGW through the synergistic interplay between a zwitterionic polymer and a low surface energy material, highlighting its promising potential in SGW treatment via membrane technology.

High-Degree Concentration Organic Solvent Forward Osmosis for Pharmaceutical Pre-Concentration.

Over half of the pharmaceutical industry's capital investments are related to the purification of active pharmaceutical ingredients (APIs). Thus, a cost-effective purification process with a highly concentrated solution is urgently required. In addition, the purification process should be nonthermal because most APIs and their intermediates are temperature-sensitive. This study investigated a high-degree concentration organic solvent forward osmosis (OSFO) membrane process. A polyketone-based thin-film composite hollow fiber membrane with a polyamide selective layer on the bore surface was used as the OSFO membrane to achieve a high tolerance for organic solvents and an effective concentration. MeOH, sucrose octaacetate (SoA), and 2M polyethylene glycol 400 (PEG-400)/MeOH solution were used as the solvent, model API, and a draw solution (DS), respectively. OSFO was performed at room temperature (23 ± 3 °C). Consequently, the 11 wt% SoA/MeOH solution was concentrated to 52 wt% without any SoA leakage into the DS. To our knowledge, there are no studies in which up to a 5 wt% concentration by OSFO has been demonstrated. However, the final feed solution contained 17 wt% PEG-400. This study demonstrates the promising potential of OSFO for pharmaceutical pre-concentration and the technical problems that need to be solved for social implementation.

Effect of forward osmosis membrane process on biogas slurry concentration

Effect of forward osmosis membrane process on biogas slurry concentration

Selective separation of volatile fatty acids, nitrogen and phosphorus from anaerobic acidogenic fermentation via forward osmosis membrane process

Selective separation and recovery of volatile fatty acids (VFA) and other valuable resources promotes a sustainable wastewater treatment system, but its cost-effective separation approaches are poorly understood. This study investigated the feasibility of applying a forward osmosis (FO) dewatering process for the selective separation of VFA, ammonium and phosphate from anaerobic acidogenic fermentation. Limited VFA rejection of fermentation broth, i.e., less than 20 %, was observed under acidic conditions, while the rejection rate was significantly increased to ∼90 % at neutral pH. The transfer of ammonium across the membranes was remarkably impacted by the feed solution pH. Lower pH (∼4) values resulted in higher rejection rates of ammonium (∼96 %), and the rate gradually declined as pH increased. The rejection of phosphate, which remained higher than 98 %, was less sensitive to pH variations. The increase in water flux promoted the rejection of VFA, ammonium and phosphate, and the membrane orientation significantly impacted the transfer of nutrients in the FO process. The active layer facing the feed solution (AL-FS) mode exhibited higher rejection rates of VFA, ammonium and phosphate than the active layer facing the draw solution (AL-DS) mode, which was ascribed to the internal concentration polarization effect. Furthermore, approximately 80 % of water could be effectively reduced from a real acidogenic fermentation liquor during the FO process; ammonium and phosphate were 3.72-fold and 4.10-fold concentrated in feed solution, respectively, and VFA was selectively separated in draw solution. The work confirmed the feasibility of utilizing FO processes in separating and enriching VFA, ammonium and phosphate from anaerobic fermentation liquors, providing meaningful information on promoting FO-based processes in treating wastewater.

Prediction of forward osmosis membrane engineering factors using artificial intelligence approach

Currently, forward osmosis (FO) is widely studied for wastewater treatment and reuse. However, there are still challenges which need to be addressed for the application of the FO on a commercial scale. In the meantime, with a strong capability to solve the complicated nonlinear relationships and to examine of the relations between multiple variables, artificial intelligence (AI) technique could be a viable tool to improve FO system performance to make it more applicable. This study aims to develop an AI-based model for supporting early control and making decision in the FO membrane system. The results show that the artificial neural networks model is extremely suitable for prediction of water flux, membrane fouling, and removal efficiencies. The most appropriate input dataset for the model was proposed, in which organic matters, sodium ion, and calcium ion concentrations played a vital role in all predictions. The best model architecture was suggested with an optimal hidden layers (2-4 layers), and neurons (10-15 neurons). The developed models for membrane fouling show strong correlation between experimental and predicted data (with R2 values for prediction of membrane fouling porosity, thickness, roughness, and density were 0.85, 0.97, 0.97, and 0.98, respectively). The prediction of water flux presented a high R2 and low root mean square error (RMSE) of 0.92 and 0.9Lm-2.h-1, respectively. Prediction of the contaminant removal exhibits a relatively high correlation between the observed and predicted data with R2 values of 0.87 and RMSE values of below 2.7%. The developed models are expected to create a breakthrough in the control and enhancement in a novel FO membrane process used for wastewater treatment by providing us with actionable insights to produce fit-for-future systems in the context of sustainable development.

A Review on the Development of an Integer System Coupling Forward Osmosis Membrane and Ultrasound Waves for Water Desalination Processes.

This review considers the forward osmosis (FO) membrane process as one of the feasible solutions for water desalination. Different aspects related to the FO process are reviewed with an emphasis on ultrasound assisted FO membrane processes. The different types of membranes used in FO are also reviewed and discussed; thus, their configuration, structure and applications are considered. Coupling ultrasound with FO enhances water flux through the membrane under certain conditions. In addition, this review addresses questions related to implementation of an ultrasound/FO system for seawater desalination, such as the impact on fouling, flow configuration, and location of fouling. Finally, the mechanisms for the impact of ultrasound on FO membranes are discussed and future research directions are suggested.

Wastewater Primary Treatment Using Forward Osmosis Introduces Inhibition to Achieve Stable Mainstream Partial Nitrification.

Achieving stable long-term mainstream nitrite oxidizing bacteria (NOB) suppression is the bottleneck for the novel partial nitrification (PN) process toward energy- and carbon-efficient wastewater treatment. However, long-term PN stability remains a challenge due to NOB adaptation. This study proposed and demonstrated a novel strategy for achieving NOB suppression by the primary treatment of mainstream wastewater with a forward osmosis (FO) membrane process, which facilitated two external NOB inhibition factors (salinity and free nitrous acid, FNA). To evaluate the proposed strategy, a lab-scale sequencing batch reactor was operated for 200 days. A stable PN operation was achieved with a nitrite accumulation ratio of 97.7 ± 2.8%. NOB were suppressed under the combined inhibition effect of NaCl (7.9 ± 0.2 g/L, as introduced by the FO direct filtration) and FNA (0.11 ± 0.02 mg of HNO2-N/L, formed as a result of the increased NH4+-N concentration after the FO process). The two inhibition factors worked in synergy to achieve a more stable PN operation. The microbial analysis showed that the elevated salinity and accumulation of FNA reshaped the microbial community and selectively eliminated NOB. Finally, an economic and feasibility analysis was conducted, which suggests that the integration of an FO unit into PN/A is a feasible and economically viable wastewater treatment process.

Selective Separation of Volatile Fatty Acids, Nitrogen and Phosphorus from Anaerobic Acidogenic Fermentation Via Forward Osmosis Membrane Process

Selective Separation of Volatile Fatty Acids, Nitrogen and Phosphorus from Anaerobic Acidogenic Fermentation Via Forward Osmosis Membrane Process

Role of organic fouling layers on the transport of micropollutants in forward osmosis membrane processes

In this study, the impact of organic fouling layers on the transport of micropollutants (MPs) during the operation of the forward osmosis (FO) process was investigated. The rejection of MPs after the formation of organic fouling layers with three model foulants (bovine serum albumin (BSA), sodium alginate (SA), and humic acids (HA)) showed that the electrostatic and hydrophobic interactions governed the transport of MPs. The negatively charged functional groups in the organic fouling layers increased the rejection of negatively charged MPs, while the rejection of positively charged and neutral MPs with high Kow was significantly decreased in the presence of an organic fouling layer. The adsorption analysis showed that the positively charged and hydrophobic MPs were preferably adsorbed into the organic fouling layers, and the elevated concentration of MPs in the organic foulant layer accelerated the diffusional transport of adsorbed MPs across the FO membranes. The SA showed higher adsorption capacities of MPs than HA or BSA, and thus a dramatic decrease in the rejection of MPs was observed. Our findings indicate that the rejection efficiencies of MPs might be overestimated when experiments are conducted without organic fouling layers. The rejection of MPs thus should be carried out in the presence of foulants in the FO process.

Enhancing the applicability of forward osmosis membrane process utilizing food additives as draw solutes

Food additives as draw solutes were investigated to improve the feasibility of forward osmosis (FO) for concentration of liquid food products. Three widely used food additives were selected: monosodium glutamate (MSG), sodium saccharine, and trisodium citrate. The osmotic pressures generated by food additives were measured to be similar or even higher than that of NaCl. However, the water flux produced by FO using food additives was 70–78% lower than that of NaCl. This observation was mainly attributed to severe internal concentration polarization (ICP). Conversely, the reverse solute flux (RSF) of food additives in the FO process was low at only 3–9% of that of NaCl, suggesting they pose a low contamination. The FO process using MSG draw solutions yielded a 15% solid content of whey. To further improve FO concentration, pressure-assisted osmosis (PAO) was adopted for dewatering whey and lactose solutions. The PAO process applying a pressure of 10 bar to feed solution increased the water flux by 36% (whey) and 49% (lactose) with a 2 M MSG draw solution, thus demonstrating the potential of the developed FO/PAO with food additive draws for the food industry.

Using Reverse Osmosis Membrane at High Temperature for Water Recovery and Regeneration from Thermo-Responsive Ionic Liquid-Based Draw Solution for Efficient Forward Osmosis.

Forward osmosis (FO) membrane process is expected to realize energy-saving seawater desalination. To this end, energy-saving water recovery from a draw solution (DS) and effective DS regeneration are essential. Recently, thermo-responsive DSs have been developed to realize energy-saving water recovery and DS regeneration. We previously reported that high-temperature reverse osmosis (RO) treatment was effective in recovering water from a thermo-responsive ionic liquid (IL)-based DS. In this study, to confirm the advantages of the high-temperature RO operation, thermo-sensitive IL-based DS was treated by an RO membrane at temperatures higher than the lower critical solution temperature (LCST) of the DS. Tetrabutylammonium 2,4,6-trimethylbenznenesulfonate ([N4444][TMBS]) with an LCST of 58 °C was used as the DS. The high-temperature RO treatment was conducted at 60 °C above the LCST using the [N4444][TMBS]-based DS-lean phase after phase separation. Because the [N4444][TMBS]-based DS has a significantly temperature-dependent osmotic pressure, the DS-lean phase can be concentrated to an osmotic pressure higher than that of seawater at room temperature (20 °C). In addition, water can be effectively recovered from the DS-lean phase until the DS concentration increased to 40 wt%, and the final DS concentration reached 70 wt%. From the results, the advantages of RO treatment of the thermo-responsive DS at temperatures higher than the LCST were confirmed.

Dynamic feed spacer for fouling minimization in forward osmosis process

In this study, a dynamic feed spacer is used to minimize the fouling problem of forward osmosis (FO) membrane process. The conceptual design of the spacer consists of a series of microturbines assembled in ladder type filament cells and termed as turbospacer. It exploits the kinetic energy of the flowing feed solution to rotate the turbines and creates high flow turbulence in the feed channel to prevent the accumulation of foulants and related performance decline. This proof of concept study employed a 3D printed prototype of the proposed spacer in a lab-scale FO experimental setup to compare their performances with a symmetric non-woven spacer of the same thickness under the same operating condition as a reference. Primary effluent from municipal wastewater treatment plant was used as feed solution for a short term (6 days) fouling experiment in this study. Outcomes of the FO fouling experiment revealed that the turbospacer resulted in (i) a factor 2 lower spacer channel pressure drop built-up, and (ii) a 15% reduction in flux decline compared to the reference symmetric spacer. Almost 2.5 times lower foulant resistance was obtained by using the turbospacer at the end of the fouling experiment. In addition, the analysis of the foulant layer growth over a particular position of the membrane surface captured by an optical coherence tomography (OCT) device at different stages of the experiment exhibited that the turbospacer produced a thinner foulant layer. In summary, the turbospacer demonstrated better fouling prevention and control in the FO process.

Comprehensive review of osmotic dilution/concentration using FO membranes for practical applications

Forward osmosis (FO) has attracted growing attention in the field of membrane-based separation technology over the last two decades. Despite recent advancements in various osmosis-assisted processes, few studies have succeeded in commercialization. This paper reviews the state-of-the-art developments of FO membrane, limitation analysis, and commercial proper applications. First, the development of FO technology in terms of FO membranes, FO draw solution (DS), and FO systems is reviewed. Based on a literature database survey spanning 1965–2020, current limitations of FO, particularly in terms of DS regeneration, energy consumption, and scale-up implementation, are identified to overcome the obstacles to commercialization. The key applications of the FO membrane process in commercial sectors are further classified into three configurations (i.e., osmotic dilution, osmotic concentration, and simultaneous osmotic dilution and concentration), and their successful applications are discussed. Since industrial demonstrations of simultaneous osmotic dilution and concentration are in progress, we believe that FO technology with no need for DS regeneration will be commercialized soon in the future.

UV/H2O2-assisted forward osmosis system for extended filtration, alleviated fouling, and low-strength landfill leachate concentrate

The forward osmosis (FO) membrane process is a good option for treating complex wastewater, such as landfill leachate, owing to its high rejection. However, organic membrane fouling and the generation of high-strength concentrate hamper efficient and environmentally friendly operation. To overcome these limitations, an integrated FO system combined with UV/H2O2 oxidation is proposed in this paper. Changes in the heterogeneous organic composition of the leachate were tracked along the treatment processes via size exclusion chromatography and excitation emission matrix combined with parallel factor analysis, which allowed us to pinpoint the organic fractions responsible for FO membrane fouling and evaluate their removal efficiency. Three fluorescent components, including tryptophan-like (C1), fulvic-like (C2), and humic-like (C3) components, were identified in the landfill leachate. A separate UV/H2O2 oxidation system led to selective removal of the organic leachate fractions, causing membrane fouling by ~80% along with the overall removal of bulk leachate by ~45%. Compared to traditional FO, the integrated system resulted in improved filtered volume (by 40%), decreased overall membrane resistance (by 30%), complete flux recovery after physical cleaning, and 50% reduction of organic carbon in the membrane concentrate. Moreover, the concentrate from the integrated FO system was characterized by a much lower abundance of large molecules, which is beneficial for the reclamation of concentrate due to its high biodegradability. This study demonstrated the effectiveness of UV/H2O2 oxidation as an integrated option for an FO system used for extended filtration, membrane fouling mitigation, and the production of low-strength landfill leachate concentrate.

Recovery of protein and carbohydrate from dairy wastewater using ultrafiltration and forward osmosis processes

The presence of protein, carbohydrate, and lipids in dairy wastewater reduces its biological treatment efficiency. However, separating these compounds before wastewater treatment will have economic benefits for the dairy industry, (i) protein and carbohydrate could be used as an alternative nutrition source of farm animals, and (ii) the efficiency of the existing wastewater treatment facilities will be improved. Membrane technology (ultrafiltration UF, nanofiltration NF, and reverse osmosis RO) in combination (UF-NF or UF-RO) has been used for the treatment of dairy wastewater. However, these technologies are pressure driven and energy intensive, further the presence of protein and carbohydrate results into fouling in NF and RO. The present study reports the application of UF and forward osmosis (FO) membrane processes. FO is a concentration driven membrane process which involves migration of water through a semi permeable membrane from low osmotic pressure (feed solution) to high osmotic pressure (draw solution). It results into less fouling than NF or RO. The present study involves an integrated treatment process with UF followed by FO, it has resulted into 65% of carbohydrate retention and 98% of protein retention.

Characterizations of Thermo-Responsive Alkyl Imidazolium Perchlorates for Forward Osmosis Membrane Process

Characterizations of Thermo-Responsive Alkyl Imidazolium Perchlorates for Forward Osmosis Membrane Process

Effect of Surfactant Properties on the Performance of Forward Osmosis Membrane Process

Effect of Surfactant Properties on the Performance of Forward Osmosis Membrane Process

A novel empirical method for predicting concentration polarization in forward osmosis for single and multicomponent draw solutions

Concentration polarization is one of the inherent problems in forward osmosis membrane process. A quantitative evaluation of concentration polarization is therefore vital to understand its impact on the performance of the forward osmosis. Limited data in the literature exists for the diffusion coefficient of mixed electrolyte or multicomponent solutions, which makes the calculation of mass transfer coefficient and solute resistance to diffusion in forward osmosis complicated. Therefore, an empirical method based on a limited set of well-defined experiments for evaluating and predicting the concentration polarization, water flux, and reverse solute flux is presented for single and mixed, or multi-ions draw solutions. The proposed method does not rely on the hydrodynamic conditions and flow regime in the system and provides an approach to measure and predict concentration polarization, water flux, and reverse salt flux when the diffusion coefficient of a feed solution (FS) or draw solution (DS) is challenging to determine. The developed numerical method is two steps method to measure internal and external concentration polarization using different concentrations of the draw and feed solutions. Experimental work was carried out with a single, and highly soluble sodium chloride (NaCl) DS and a mixture of NaCl and magnesium sulphate (MgSO4) were used as a selected multicomponent DS. The results showed a 95% to 99% agreement with the experimental data.