Advancing electrodialysis: Harnessing the potential of spiral-wound membrane stacks for improved desalination-efficiency and cost-efficiency

Membrane separation technology encompasses a variety of processes, of which electrodialysis (ED) has become one of the irreplaceable technologies due to its high concentration factor and energy saving. Currently, the main membrane stacks of ED technology on the market are plate-and-frame membrane (PFM) stacks, while there are almost no spiral-wound membrane (SWM) stacks. The SWM stacks have many advantages, such as higher mass transfer efficiency, higher packing density, etc. Inspired by its advantages, we have designed and assembled a SWM for ED. In this study, the PFM and SWM stacks in the efficacy of the two processes were compared using the Finite Element Method to simulate the distribution of fluid and electric fields within the stacks. The desalination efficiency of SWM has been improved compared with that of PFM. In particular, when the voltage is 36 V, the single path desalination rate is 98.7 %. The effective area of the membrane stack has been increased from 63.6 % to 88.9 % since the components of the SWM stack are more efficient and easy to assemble. Due to its low cost, excellent performance and partial fluid simulation, it is believed that this work can provide an inspiration for the assembly of membrane stacks.