## 1 Introduction  
Water scarcity is a critical challenge for human society. Besides surface water and fresh groundwater, brackish groundwater is another crucial source of water supply. However, it is necessary to remove salt from brackish groundwater or other saline water to make it drinkable. Desalination, especially from brackish water sources, plays a vital role in augmenting freshwater supplies. While reverse osmosis (RO) dominates the desalination industry, electrodialysis (ED) has garnered increasing attention due to its faster kinetics, solute-solute selectivity, and ability to recover valuable ions from diverse feed streams like brackish water [1]. These merits make ED particularly suitable for resource recovery and specialized desalination applications. Recent studies further highlight the growing interest in ED for its distinct advantages over RO. For instance, ED offers the ability to recover valuable ions directly during desalination, making it highly efficient in processes such as brine management and metal recovery. [PERSON] et al. (2021) demonstrated how optimal operational profiles in ED units can enable efficient ion recovery, especially for applications requiring high-value material recovery [2]. Additionally, [PERSON] et al. (2022) reviewed ED's capabilities for selective removal and recovery of metals, underscoring its potential in wastewater treatment and industrial process streams [3]. This feature not only contributes to resource recovery but also reduces the environmental impact of desalination by minimizing waste. Moreover, ED systems are characterized by faster desalination kinetics compared to pressure-driven processes like RO. The direct migration of ions under an electric field significantly reduces energy requirements for brackish water desalination [4]. Unlike RO, which relies on high-pressure membranes, ED can operate at lower pressures and is less prone to fouling and scaling. This reduces maintenance requirements and operational costs, particularly in industrial applications with varying water quality. Furthermore, the selective ion transport capability of ED enables it to separate specific ions, which is advantageous for specialized desalination needs or the production of tailored water compositions. To enable efficient ion transport and separation in electrodialysis (ED), a variety of ion exchange membranes (IEMs) based on different materials have been developed, each offering distinct advantages and limitations. Sulfonated poly(ether ether ketone) (SPEEK) membranes are widely utilized due to their high thermal stability, chemical resistance, and tunable ion exchange capacity. These properties make them suitable for harsh desalination conditions, as demonstrated by their improved proton exchange performance when doped with ionic liquids, enhancing conductivity and selectivity [5]. Polyethersulfone (PES) membranes, particularly when sulfonated, exhibit good mechanical strength and chemical durability, making them a common choice for cost-effective ED applications [6]. Similarly, polyvinylidene fluoride (PVDF) has garnered attention as a robust base material, offering excellent chemical resistance and stability. PVDF membranes, when modified to include cation exchange functionalities, have shown improved performance in ED by optimizing crystallinity and mitigating co-ion leakage [7]. Polystyrene-based membranes, functionalized with sulfonic or quaternary ammonium groups, are another prevalent material due to their high ion exchange capacity and ease of fabrication. However, their performance can be enhanced further with radiation-induced grafting, as demonstrated by [PERSON] et al., who achieved superior performance for reverse electrodialysis applications [8]. Additionally, polyamide-based membranes are emerging as promising alternatives for cation-selective transport. These membranes, traditionally used in reverse osmosis, have demonstrated high selectivity and durability in electrodialysis, enabling efficient ion transport while maintaining chemical stability [9].