Research on Forward Osmosis Membrane Technology Still Needs Improvement in Water Recovery and Wastewater Treatment

Abstract

Forward osmosis (FO) has become an evolving membrane separation technology to recover water due to its strong retention capacity, sustainable membrane fouling, etc. Although a good deal of research has been extensively investigated in the past decades, major challenges still remain as follows: (1) the novel FO membrane material properties, which significantly influence the fouling of the FO membranes, the intolerance reverse solute flux (RSF), the high concentration polarization (CP), and the low permeate flux; (2) novel draw solution preparation and utilization; (3) salinity build-up in the FO system; (4) the successful implementation of the FO process. This work critically reviews the last five years’ literature in development of the novel FO membrane material, structure in modification, and preparation, including comparison and analysis on the traditional and novel draw solutes coupled with their effects on FO performance; application in wastewater treatment, especially hybrid system and integrated FO system; fouling mechanism; and cleaning strategy as discussed in the literature. The current barriers of the research results in each hotspot and the areas that can be improved are also analyzed in detail. The research hotspots in the research and development of the novel membrane materials in various countries and regions have been compared in recent years, and the work of variation in pop research hotspots in the past 10 years has been analyzed and the ideas that fill the blank gaps also have been proposed.

A Review of CFD Modelling and Performance Metrics for Osmotic Membrane Processes

“…Therefore, the FO process requires additional operations to continuously or effectively regenerate the draw solution. In addition, the FO process in the FO–RO hybrid system can be beneficial in terms of freshwater recovery and enhanced pollutants removal (e.g., organic matter, scaling precursors and boron) [ 129 , 130 ]. It has been demonstrated that a FO hybrid process shows potential for desalinating water; for example, a FO–RO hybrid plant built in South Korea with a capacity of 2000 m 3 /day utilised an FO step to dilute seawater from an inlet solute mass fraction ( w b,in ) of 0.034 to a range of 0.010–0.013, reducing energy consumption by up to 25% compared with traditional SWRO [ 131 ].…”

Shale Oil and Gas Produced Water Treatment: Opportunities and Barriers for Forward Osmosis

“…These membranes have shown reduce ICP and have high porosity and a strong pore structure [62]. The use of nanomaterials within the support layer of various types of FO membranes has with been proven to strengthen the membrane's structure, increase water flux, and reduce ICP [63]. Other materials are being incorporated into FO membranes, such as aquaporin (AQP).…”

“…An ideal DS would be stable, inexpensive, and accessible, provide high osmotic pressure, offer efficient recovery methods, have low toxicity, and deliver high water flux. DS can be separated into categories [63] [35,65]. Sodium chloride is the most commonly used DS since it is inexpensive, accessible, very soluble, and allows for high osmotic pressure [66].…”

“…These DSs are not typically used in PW treatment. MNPs are a DS that has become inclined to many researchers due to their high recovery rate and osmotic pressure [63]. These DSs are created by using a polyol and thermal decomposition process to create hydrophilic magnetic nanoparticles [67].…”

Forward Osmosis: A Critical Review

“…While there have been a couple of review papers in recent years concerning the basic principles of FO [21][22][23][24], draw solutions [22,[25][26][27][28][29][30][31], applications [21,25,27,[32][33][34][35][36][37][38][39], (bio)fouling [22,25,26,30,[40][41][42][43][44][45][46], membrane fabrication [19,23,30,35,39,43,47,48], or upscaling [49,50], we, for the major part of this review, discuss the challenges of FO evidences from various literatures to prove the unreliability of the existing structural parameter approaches. In addition, we will highlight that, beyond a certain water permeability, the true bottleneck is the mechanical support of the membrane instead of the selective membrane layer.…”