A statistics-based forward osmosis membrane characterization method without pressurized reverse osmosis experiment

A comprehensive review of standalone and hybrid forward osmosis for water treatment: Membranes and recovery strategies of draw solutions

Revised external and internal concentration polarization models to improve flux prediction in forward osmosis process

Forward osmosis (FO) has recently emerged as a new separation platform for a range of applications that are currently not possible for other membrane processes. This review paper covers key aspects of FO development with a specific emphasis on current technical challenges for practical applications. Main hurdles in the transition of FO from a lab-scale process to large scale applications include low-performance membranes, development of suitable draw solute, inherent transport phenomena (e.g. concentration polarization and reverse solute flux), membrane fouling and subsequent membrane cleaning. Several new FO membranes have been developed with some improved performances but no membrane has yet been found convincing in all of the key performance indicators. Draw solutes have been broadly investigated but mainly at the lab-scale. There have only been very few pilot-scale studies, most of them using inorganic salts as draw solutes. Development of thermo-responsive draw solutes and TFC membranes have been reported to be most effective in reducing reverse solute flux while altering the hydrodynamic conditions and the use of ultrasonication along with exploring other viable options have been suggested to tackle external and internal concentration polarization respectively. Although membrane fouling types and mitigation strategies have been extensively explored, this review also highlights the need for further research in biofouling for long-term FO operation.

Exploring the use of cheap natural raw materials to reduce the internal concentration polarization in thin-film composite forward osmosis membranes

Toward a combined system of forward osmosis and reverse osmosis for seawater desalination

A state-of-the-art protocol to minimize the internal concentration polarization in forward osmosis membranes

Internal concentration polarization (ICP) within the forward osmosis (FO) membrane affects the reduction of driving force. The magnitude of ICP in the FO membrane was investigated experimentally by measuring water flux in both spiral wound (SW) and flat-sheet (FS) modules with different draw solutions (sodium chloride, sodium sulfate, and disodium phosphate). The FO SW module always shows inferior water flux performance to the FO FS module. The water flux in the FO SW module can be easily estimated by just changing structure parameter. The estimated structure parameter in the FO SW module is 9.1325×10−4 m, which is quite higher than 4.2×10−4 m in the FO FS module. The increase of the structure parameter is attributed to the bending of the FO membrane in the SW module. It can be concluded that a module design such like SW type is not suitable for the FO process.

Life-cycle assessment of two potable water reuse technologies: MF/RO/UV–AOP treatment and hybrid osmotic membrane bioreactors

Synthesis and characterization of thin film nanocomposite forward osmosis membranes supported by silica nanoparticle incorporated nanofibrous substrate

Effects of membrane orientation on fouling characteristics of forward osmosis membrane in concentration of microalgae culture

Concentration of brine by forward osmosis: Performance and influence of membrane structure

A thin, porous, and hydrophilic sublayer is essential in the forward osmosis (FO) process to minimize the structural parameter (S), thereby reducing internal concentration polarization (ICP). In this study, the polysulfone (PSf) sublayer of the FO membrane is modified with an amphiphilic graft copolymer, poly(sulfone)- graft -poly(2-hydroxyethyl methacrylate) (PSf-g-PHEMA). The PHEMA with terminal alkyne functional groups is synthesized via atom transfer radical polymerization (ATRP) and subsequently grafted onto azide-functionalized PSf using click reaction. Sublayers are prepared through the phase inversion process by adding different concentrations of the PSf-g-PHEMA copolymer to the PSf casting solution. Different analyses reveal substantial enhancements in the properties of the copolymer-blended sublayer, including improved hydrophilicity, porosity, pure water permeability, and optimized morphology. These improvements are attributed to the hydrophilic segments of the graft copolymer, which influence the phase inversion rate. The membrane containing 10 wt.% PSf-g-PHEMA exhibited the highest water flux in both pressure-retarded osmosis (PRO, 34.5 LMH) and FO (19.4 LMH) modes, compared to the unmodified thin-film composite (TFC) membrane (5.9 LMH). This performance is associated with a significantly reduced structural parameter (S, 478 μm), indicating effective mitigation of ICP. Overall, these findings highlight the significant potential of amphiphilic graft copolymers to enhance the performance of TFC-FO membranes. • Poly(sulfone)- graft -poly(2-hydroxyethyl methacrylate) (PSf-g-PHEMA) established as functional additive • Integration of PSf-g-PHEMA yields optimized PSf-based sublayers for polyamide thin-film composite forward osmosis (FO) membranes • Amphiphilic PSf-g-PHEMA as membrane modifier enhances FO performance by reducing the structural parameter

Membrane fouling and process performance of forward osmosis membranes on activated sludge

A support assisted by photocatalytic Fe3O4/ZnO nanocomposite for thin-film forward osmosis membrane

• Textile wastewater was treated by simultaneous forward osmosis and reverse osmosis. • FO draw solution was continuously concentrated by RO. • Chemical oxygen demand and total organic carbon were rejected above 99%. • Simultaneously, clean water was obtained as the reverse osmosis permeate. The concerning and abundant textile wastewater can be treated by forward osmosis (FO) in order to reduce its volume and simultaneously recover clean water. However, the productivity of FO depends on the concentration of the draw solution that is used. In this work, a simultaneous application of FO and reverse osmosis (RO) is proposed. The HFFO14® FO membrane (Aquaporin, Denmark) was employed to concentrate a real textile wastewater, whereas the SW30-2540 (DuPont, USA) RO membrane was employed to simultaneously regenerate the draw solution, which consisted in a 0.7 M NaCl solution, and to obtain a clean water stream. The concentration of the textile wastewater increased until 90% water recovery was achieved. The rejection values obtained for the chemical oxygen demand and total organic carbon were in the range 99 – 100%. Afterwards, the previously concentrated textile wastewater was again processed until a volume concentration factor of 16.5 was reached. Stable values of permeate flux (around 4 L/h·m 2 ) were obtained in the FO process, whereas the reverse osmosis step permitted the maintenance of a stable conductivity in the draw solution and provided clean water as permeate.