Quantitative evaluation of concentration polarization under different operating conditions for forward osmosis process

This paper was aimed to study the efficiency of forward osmosis (FO) process as a new application for the treatment of wastewater from textile effluent and the factors affecting the performance of forward osmosis process.The draw solutions used were magnesium chloride (MgCl2), and aluminum sulphate (Al2 ( SO4)3 .18 H2O), and the feed solutions used were reactive red, and disperse blue dyes.Experimental work were includes operating the forward osmosis process using thin film composite (TFC) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), feed solutions concentration (5 – 30 mg/l), draw solutions flow rate (10 – 50 l/hr), feed solutions flow rate (20-60 l/hr), constant pressure and temperature were maintained at 0.5 bar and 30ºC respectively. And includes operating the forward osmosis process using cellulose triacetate (CTA) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), and feed solutions concentration (5 – 30 mg/l), constant temperature at 30ºC. It was found that water flux increases with increasing draw solution concentration, and feed solution flow rate and decreases with increasing draw solution flow rate and feed solution concentration for TFC and CTA. It was found MgCl2 given water flux larger than Alum. And also found that reactive red given water flux larger than disperse blue.The experiments also show that CTA membrane gives higher water flux than TFC membrane for forward osmosis operation. The increase in water flux for CTA is about 12.85% than TFC.

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

Numerical analysis of spacer impacts on forward osmosis membrane process using concentration polarization index

Concentrating molasses distillery wastewater using biomimetic forward osmosis (FO) membranes

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

Forward osmosis processes are an emerging set of technologies that show promise in the treatment of complex and impaired water streams (e.g., those encountered in industrial wastewater treatment and the extraction of unconventional oil resources). The effective operation of these systems requires that the operating conditions be chosen wisely based on the membrane to be used and the streams to be treated. In this work, to aid in the design of these systems, an analytical model was developed that describes the module-level performance (i.e., water recovery rate and separation factors of the feed and draw solutes) for cocurrent and countercurrent forward osmosis systems in the thermodynamic limit of osmotic equilibrium. In the limit of osmotic equilibrium, the model expresses the recovery rate and separation factors in terms of the operating conditions (e.g., the flow rates and concentrations of the feed and draw solutions) and the characteristic membrane transport properties (e.g., the hydraulic and solute permeability coefficients). The model was validated by comparing its predictions with numerical simulations of the full system of governing equations: strong agreement between the model predictions and numerical simulations was observed. Analysis of the model demonstrates that the reverse flux selectivity, the ratio of the forward water flux to the reverse draw solute flux, is a key parameter in the design of forward osmosis systems that controls the maximum solute rejection that the systems can achieve at osmotic equilibrium. Further analysis shows that the flow ratio, the ratio of the inlet flow rate of the draw solution to the inlet flow rate of the feed solution, is an important design parameter. Specifically, in countercurrent operation, a critical value of the flow ratio that maximizes the recovery rate was identified.

Integration of Forward Osmosis Membrane Bioreactor (FO-MBR) and Membrane Distillation (MD) units for water reclamation and regeneration of draw solutions

Modeling of a forward osmosis and a pressure-retarded osmosis spiral wound module using the Spiegler-Kedem model and experimental validation

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.

ABSTRACTIn this study, we fabricated a nanofibrous composite (NFC) membrane as a substrate to produce forward osmosis (FO) membranes, and we also assessed the use of liquid fertilizer as a draw solution for the FO process in order to produce agricultural irrigation water. Commercial cellulose triacetate (CTA) and thin-film composite (TFC) FO membranes were included in this study. Under FO tests, the NFC, CTA, and TFC membranes achieved initial osmotic water flux values of 35.31, 6.85, and 3.31 L/m2·h and final osmotic water flux values of 12.62, 6.31, and 3.85 L/m2 h, respectively. The reason for the high osmotic water flux of the NFC membrane is because its nanofiber layer has low tortuosity, high porosity, and a low thickness, resulting in a reduction in the internal concentration polarization phenomenon. When liquid fertilizer was used as the draw solution, the water flux values in the FO experiments for the NFC, CTA, and TFC membranes were 15.54, 5.46, and 2.54 L/m2 h. Finally, our results revealed that the FO process using liquid fertilizer as a draw solution can be applied to produce agricultural irrigation water from brackish water and the newly fabricated NFC membrane can be applied to the FO process.

Exploration of food preservatives as draw solutes in the forward osmosis process for juice concentration

Factors affecting flux performance of forward osmosis systems

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

Forward osmosis for oily wastewater reclamation: Multi-charged oxalic acid complexes as draw solutes

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