Osmotically Driven Membrane Processes - Approach, Development and Current Status (original) (raw)
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Forward Osmosis Process: State-Of-The-Art of Membranes
Separation & Purification Reviews, 2019
Forward osmosis (FO) is a membrane-based process that explores the osmotic pressure difference between a feed solution and a draw solution to induce water transport across a semipermeable membrane. Water transport results in the dilution of the draw solution which is reconcentrated using a recovery process. Different from the reverse osmosis process, FO requires lower grade energy and has other advantages, namely, a wide range of applications and a reversible fouling phenomenon of FO membranes. In spite of its many advantages, the FO process is facing drawbacks among which the lack of high-performance membranes. Today, the development of improved FO membranes, capable of achieving a high water flux with a very low reverse salt flux is one of the biggest concerns of membrane scientists. This paper summarizes the basic principle of the FO process, some modern applications, and the main challenges related to membranes. It also describes the progresses in FO membrane development, particularly regarding the membrane manufacturing techniques, commercially available, and R&D membranes.
Forward Osmosis Membrane: Review of Fabrication, Modification, Challenges and Potential
Membranes, 2023
Forward osmosis (FO) is a low-energy treatment process driven by osmosis to induce the separation of water from dissolved solutes/foulants through the membrane in hydraulic pressure absence while retaining all of these materials on the other side. All these advantages make it an alternative process to reduce the disadvantages of traditional desalination processes. However, several critical fundamentals still require more attention for understanding them, most notably the synthesis of novel membranes that offer a support layer with high flux and an active layer with high water permeability and solute rejection from both solutions at the same time, and a novel draw solution which provides low solute flux, high water flux, and easy regeneration. This work reviews the fundamentals controlling the FO process performance such as the role of the active layer and substrate and advances in the modification of FO membranes utilizing nanomaterials. Then, other aspects that affect the performance of FO are further summarized, including types of draw solutions and the role of operating conditions. Finally, challenges associated with the FO process, such as concentration polarization (CP), membrane fouling, and reverse solute diffusion (RSD) were analyzed by defining their causes and how to mitigate them. Moreover, factors affecting the energy consumption of the FO system were discussed and compared with reverse osmosis (RO). This review will provide in-depth details about FO technology, the issues it faces, and potential solutions to those issues to help the scientific researcher facilitate a full understanding of FO technology.
Forward osmosis membranes and processes: A comprehensive review of research trends and future outlook, 2020
Recently, Forward Osmosis (FO) desalination process has been widely investigated as a potential technology that could minimize the drawbacks of traditional desalination processes. To review the past, current, and future research scope of the FO desalination process, a statistical analysis that gives insights on the FO topics of interest is needed to assist researchers in the development of the FO technology. The main objective of this work is to conduct a survey highlighting the general and specific research trends in FO technology topics. The level of research interest is quantified based on the number of publications in each area collected from Science Direct and Scopus databases from 1999 to 2020. This survey indicated an increasing number of publications on the FO processes and membranes technology. The topics of interest are fouling phenomenon, draw solutions, membrane fabrication and modification. Some potential research areas highlighted in this review to help researchers to further advance the FO technology. This review reveals that recycling the draw solution and energy consumption are the most important research areas that have shown growth in the number of publications over the last eight years. An increase of publications was also found in the treatment of the organic matter over the last decade. To further promote FO process in industry, developing FO membranes, optimizing the energy consumption, and establishing an effective recovery system are the most essential topics. Thus, the interest in this process is expected to be continued in the future.
The forward osmosis process has obtained renewed interest nowadays and it might become an alternative solution for many industrial applications to meet the current and future requirements for potable water. The FO process depends on the osmotic pressure gradient between a high salinity draw solute and low salinity feed solution across a semi-permeable membrane to extract pure water. Despite the potential advantages of FO, there are some technical drawbacks that hinder FO application for water desalination. One of the most significant critical challenges is the need for membrane compatible with the FO process. To improve FO desalination feasibility, membrane development is required to obtain maximum water permeability and minimum reverse solute flux over long-term operations. Therefore, this review starts by demonstrating the fundamentals and membrane development over the years. Fabrication modifications for the support layer of FO membranes and the crucial challenges of the FO process are summarized. Recent trends of the chemical modifications of the bulk and substrate are discussed. The advantages and disadvantages of the modifications on the FO membrane productivity are also addressed. Finally, concluding with future perspectives.
DESALINATION AND WATER TREATMENT, 2018
Generally, forward osmosis (FO) membrane performance is defined based on its intrinsic parameters, namely the water permeability (A), solute permeability (B), and structural parameter (S). This study was conducted to examine the performance of the commercial membrane NF2 in an FO system and to validate and compare the intrinsic value of A, B, and S obtained by single stage-stage and two-stage methods. The NF2 membrane was unable to demonstrate a good configuration for an FO membrane due to its membrane structure. Comparing the two different orientations in the single-stage method, it appears that both orientations display distinct sets of intrinsic values for the same membrane type. A comparison on the two-stage methods between the pressure-retarded osmosis-FO and reverse osmosis (RO)-FO methods reveals a new standard for the two-stage methods where higher fluxes must be produced from the first stage in order to attain an accurate value of S at the second stage. Additionally, the RO-FO methods were found to be not relevant for testing the ability of a membrane for FO application due to the hydraulic pressure involved during the compaction procedure. The two-stage method with proposed new standards can be the ideal testing procedure for the membrane in FO applications. This is because all the intrinsic values can be separately determined considering all the possible concentration polarization that might occur with both orientations compared with the attempts of fitting all possible values in the generated equations, as in single-stage methods.
Recent Progresses of Forward Osmosis Membranes Formulation and Design for Wastewater Treatment
Water, 2019
Production of potable water or reclaimed water with higher quality are in demand to address water scarcity issues as well as to meet the expectation of stringent water quality standards. Forward osmosis (FO) provides a highly promising platform for energy-efficient membrane-based separation technology. This emerging technology has been recognized as a potential and cost-competitive alternative for many conventional wastewater treatment technologies. Motivated by its advantages over existing wastewater treatment technologies, the interest of applying FO technology for wastewater treatment has increased significantly in recent years. This article focuses on the recent developments and innovations in FO for wastewater treatment. An overview of the potential of FO in various wastewater treatment application will be first presented. The contemporary strategies used in membrane designs and fabrications as well as the efforts made to address membrane fouling are comprehensively reviewed. F...
Strategies in Forward Osmosis Membrane Substrate Fabrication and Modification: A Review
Membranes, 2020
Forward osmosis (FO) has been recognized as the preferred alternative membrane-based separation technology for conventional water treatment technologies due to its high energy efficiency and promising separation performances. FO has been widely explored in the fields of wastewater treatment, desalination, food industry and bio-products, and energy generation. The substrate of the typically used FO thin film composite membranes serves as a support for selective layer formation and can significantly affect the structural and physicochemical properties of the resultant selective layer. This signifies the importance of substrate exploration to fine-tune proper fabrication and modification in obtaining optimized substrate structure with regards to thickness, tortuosity, and porosity on the two sides. The ultimate goal of substrate modification is to obtain a thin and highly selective membrane with enhanced hydrophilicity, antifouling propensity, as well as long duration stability. This r...
Desalination, 2020
The main reason for the lower water flux, than expected, in the forward osmosis (FO) process, is the internal concentration polarization (DICP). Usually, the structural parameter (S) is used as an indicator of the intensity of DICP. Small S value is desirable for the FO membrane due to the low DICP. However, due to design and construction problems, structural parameter reduction has some drawbacks. In this work, DICP reduction in FO membranes will be investigated using an approach other than structural parameter reduction. Accordingly, during the FO process, the feed solution (FS) valve is opened and closed at a constant period of time (feed valve timing (FVT)). Four types of FO membranes with different S parameters were used. The effects of the implementation of the proposed protocol on the water flux (J w), reverse salt flux (J s), specific reverse solute flux (J s /J w) and effective driving force were investigated. The effects of the S parameter and draw solution (DS) concentration also investigated separately. The results showed that the proposed protocol significantly increased J w. Also, the values of J s /J w decreased with increasing the FVT values and reached the lowest level in the practical recovery time (PRT).
DESALINATION AND WATER TREATMENT, 2017
Forward osmosis (FO) is a membrane process that makes use of the osmosis phenomenon for the transport of water from a feed solution to a draw solution across a highly selective membrane under a driving force provided by the osmotic pressure difference between the two solutions. Based on energy consumption, this technology has got an edge over others. However, limited advancement on theoretical modeling for prediction of performance, lack of an ideal FO draw solution, concentration polarization and lack of economic feasibility have made this technology to proceed through further research with an objective of commercialization from 1970 to 2016. Although the technology has many potential applications, like wastewater treatment, membrane bioreactor, oil and gas, pharmaceutical, food and beverage etc., it still faces considerable limitations, including concentration polarization, membrane development and characterization, reverse solute diffusion, development of draw solution and their recovery. In order to address these issues more research is required. This paper presents a state-of-art review on FO technology covering types of membrane, draw solute, their characteristics, concentration polarization, identification of parameters, dynamic modeling of separation, novel membrane and hybrid systems from 103 literatures.
Jurnal Teknologi, 2017
Osmotically-driven forward osmosis (FO) has gained significant attention in the last decade due to its potential application in various disciplines. Draw solution serves as the driving force in FO process for inducing water transport across the membrane. FO technology can be used to reject or concentrate high valuable products in the chemical and bioprocess industries which often encounter great challenge in terms of dilute product formation. In this study, commercial cellulose triacetate (CTA) flat sheet FO membrane was investigated using several types of inorganic draw solute. Pure water fluxes ranged from 5.20 to 6.30 L.m-2 .h-1 were achieved for selected draw solutes. The reverse solute leakage was shown by the increment of conductivity in the feed solution. Among the draw solutes, NaCl demonstrated highest reverse solute leakage (72.45 µS cm-1) attributed to its relatively smaller molecular size. The water fluxes at feed to draw solution volume ratios of 1:2 and 1:3 were found to be slightly lower than that to the volume ratios of 1:0.6 and 1:1. With respect to sodium succinate feed solution, MgCl2 was capable of generating higher osmotic pressure and thus higher water flux was observed compared to NaCl draw solute. Overall, the selected inorganic draw solutes demonstrated encouraging FO performances and could be used for concentrating sodium succinate solution.