Critical Reviews in Environmental Science and Technology
2019
M. OBAID; MOHAMMAD ALI ABDELKAREEM; SEUNGHO KOOK; HAK-YONG KIM; NIDAL HILAL; NOREDDINE GHAFFOUR; S. KIM
Abstract
Research on membrane technology to provide fresh water while considering inextricably linked energy issues has resulted in remarkable accomplishments in the production of membranes, such as thin film composite (TFC) membranes, for relatively low-energy desalination and wastewater reclamation via the forward osmosis (FO) process. Exhaustive and continuous efforts in the enlargement of TFC membranes to achieve an excellent combination of flux and selectivity have revealed a considerable need to fabricate an appropriate substrate. Electrospinning, as a cheap, scalable, and simple technique, is capable of producing electrospun mats with distinctive features. These features make electrospun nanofibers (ENs) a promising substrate for TFC-FO membranes, resulting in tremendous achievements in enhancing membrane performance. Since 2011, rapid progress has been made in applying electrospinning to fabricate ENs substrates for TFC-FO membranes. This paper reviews progress in the fabrication and modification of TFC membranes supported by ENs substrates for FO applications. The theoretical background of FO, discussing the main problems associated with the use of conventional substrates, progress in applying electrospinning to overcome these problems, including breakthrough achievements in ENs substrates for FO, the synthesis and characterization of such substrates, and a comparison of energy consumption between FO and other desalination techniques were covered.
Electrospinning
The nanofibers obtained by this technique can be aligned, can be produced continuously, and have high surface-to-volume ratios (Wang et al., 2017). These advantages make the electrospinning technique highly interesting for both academic and industrial applications. A huge number of reports have been published on this technique, as shown in Figure 6b, and production on an industrial scale (i.e. 2000 m2/day capacity on one production line) has been achieved (Figure 6c) (Ding, Hou, Zhao, Zhu & Fong 2016). Furthermore, both lab- and industrial-scale electrospinning equipment is now available on the market (Figure 6d–f) (Elmarco, 2018; INOVENSO Co, 2018; LINARI NanoTech, 2018; Nadetech Innovations, 2018; NanoNC, 2018; TONG LI TECH, 2018).