Forward osmosis membranes for desalination and wastewater treatment: Review of recent advances in electrospun nanofiber-based substrates, challenges, and future research recommendations

Forward osmosis (FO) technology has great potential for water purification applications but has not been commercialized on a large scale due to the lack of a specific membrane structure. The main problem with FO technology is the internal concentration polarization (ICP) that occurs within membrane substrates. Electrospun nanofiber (ESNF) based membrane substrates are considered a promising class of materials for thin-film composite (TFC) membranes for FO for water and wastewater treatment applications due to their unique properties, such as high porosity with interconnected pore structure. The main objective of this work is to review recent developments in the fabrication of ESNF-based substrates using different methods to develop TFC-FO membranes. Some potential fabrication methods are highlighted in this review to help researchers scale up FO membrane technology. To further advance the use of ESNF-based TFC-FO membranes in various water treatment applications such as desalination, heavy metal ion removal, and bacteria removal, some important challenges such as ICP, fouling, lack of mechanical strength, etc. need to be solved. Therefore, it is expected that interest in this process will continue to increase with the help of advanced nanotechnologies such as hybrid membranes, surface modification, cross-linking, layer-by-layer deposition of polyelectrolytes, etc.