# Special Issue on Wastewater Treatment and Reuse Technologies
## 6 Synthesis and Fouling Control of Membranes for Wastewater Treatment  
Searwater desalination by reverse osmosis (RO) membrane has been widely utilized to tackle the shortage of fresh water in different regions of the world. However, a large amount of brine wastewater is produced as a by-product of desalination [23]. The treatment efficiency of thermally driven processes such as membrane distillation (MD) is less dependent on feed solution concentration, and can be regarded as a promising candidate in brine wastewater treatment [24]. However, the available MD membranes suffer from fouling/scaling and pore wetting. Pervaporation is also a thermally driven process, but the available membranes have been developed for organic solvent dehydration (containing low water content) and, thus, are not suitable for desalination where water is the major component in-feed. The article \"_Suppressing Salt Transport through Composite Peraporation Membranes for Brine Desalination_\" by [PERSON] et al. [25], explored a series of composite polyvinyl alcohol (PVA)/Polyvinylidene fluoride (PVDF) membranes to suppress salt transport through the membrane during brine treatment. By incorporating a small amount of graphene oxide into the PVA matrix, the authors further improved salt rejection during extended desalination operation. The pervaporation membranes fabricated in this study could potentially be used for brine treatment.  
As noted above, one of the concerns with respect to the full scale commercialization of the membrane distillation technique for wastewater treatment is the lack of membranes ensuring long term stable operation. To this end, [PERSON] et al. [26], in their paper, \"_Functionalization of a Hydrophilic Commercial Membrane Using Inorganic-Organic Polymers Coatings for Membrane Distillation_\", carried out surface modification of a commercially available hydrophilic polyethersulfone membrane. Through hydrophobic coating using a commercially available technique, the surface contact angle of the membrane could be increased from 27\({}^{\circ}\) up to 110\({}^{\circ}\). The stability of the coating was confirmed in a 100 h trial as a preliminary assessment.  
Low-pressure submerged microfiltration and ultrafiltration applications have become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs) for wastewater treatment. Membrane fouling is the Achilles heel of submerged membrane technologies [27; 28]. The article \"_The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review_\" by [PERSON] et al. [29] provides a comprehensive landscape of current state-of-the-art of submerged hollow fiber membrane systems. This review serves as a guide for further improvements in submerged membranes and their applications.  
This work was partially funded by seed grants from GeoQuEST research Centre and the Faculty of Engineering and Information Sciences of the University of Wollongong, Australia. Sincere thanks are due to all the authors and peer reviewers for their valuable contributions to this special issue. Finally, we place on record our gratitude to the editorial team of Applied Sciences.  
The authors declare no conflict of interest.