Potential application of the draw solution system based on trisodium α-DL-alanine diacetate in forward osmosis desalination systems

This study aimed to discover the potential application of the draw solution system based on trisodium α-DL- alanine diacetate (MGDA draw solution) in forward osmosis (FO) desalination systems through the optimization of some important operational parameters, the investigation of fouling behaviours after long-term operation and the efficiency of mitigating strategies, and the analytical of some key quality properties of the produced freshwater. Optimization results suggested that in the investigated range, inlet temperature was the main operational parameters that influence the osmosis performance of the MGDA draw solution. Under the optimized operational parameters (inlet pressure difference = 0.4 bar on the feed side, inlet temperature = 30 °C, and feed side inlet flow rate = 250 mL•min−1), the osmosis performance obtained were Jw = 9.996 ± 0.192 LMH and Rds = 0.3580 ± 0.0020 g•L−1. Furthermore, experimental results also emphasized the advantages of MGDA solution, which were low tendency of membrane fouling and the relatively ease of membrane cleaning. Finally, experiments on real brackish water samples confirmed the potential application of the MGDA draw solution in FO desalination systems, with the produced freshwater meeting key requirements as recommended in the National Technical Regulation QCVN 01-1:2018/BYT.