## 1 Introduction
Recent developments in ED membrane technology have led to promising innovations, including the incorporation of advanced materials such as metal-organic frameworks (MOFs) for enhanced efficiency and nanoparticles for improved ion selectivity. Despite these achievements, many approaches face challenges due to complex synthesis methods, high costs, and limited scalability. For instance, [PERSON] et al. developed cation exchange membranes using poly(p-phenylene terephthalamide) (PPTA) nanofibers and 2,5-diaminobenzenesulfonic acid (DSA), which demonstrated exceptional thermal stability, solvent resistance, and ion exchange capacity. However, this method required intricate fabrication processes, producing membranes with a salt removal rate of 95-99% for Na\({}_{2}\)SO\({}_{4}\) and (NH\({}_{4}\))\({}_{2}\)SO\({}_{4}\) over 220 min, at a current density of \(\sim\)32 mA/cm\({}^{2}\)[10]. Similarly, [PERSON] et al. reported anion exchange membranes fabricated with brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) and dimethylethanolamine (DMEA), achieving an impressive ion exchange capacity (1.38 mmol/g) and low resistance (1.43 \(\Omega\cdot\)cm\({}^{2}\)). Despite their effectiveness in removing 80% of conductivity after 100 min, the process involved significant complexity in chemical handling [11]. [PERSON] et al. further explored zinc MOFs combined with sulfonated polyethersulfone (sPES) to create composite membranes, achieving a 94.1% salt removal rate in 200 min and low energy consumption (1.02 kWh/kg salt removed). However, such methods also require precise material handling and multi-step synthesis [12]. [PERSON] et al. demonstrated the scalability of sulfonated poly(ether ether ketone) (SPEEK) membranes, which achieved 67.6% salt removal with notable current efficiency (78.2%) [13]. Additionally, [PERSON] et al. introduced sub-nanoporous polyethersulfone membranes with excellent ion separation selectivity (e.g., K\({}^{+}\): Na\({}^{+}\): Li\({}^{+}\): Mg\({}^{2+}\) ratios of 83:56:14:1 for 10 min under UV sensitization) [14]. However, their industrial applicability remains constrained by scalability challenges. Other studies have explored enhancing ion-exchange membranes with nanoparticles. [PERSON] et al. achieved improved antibacterial properties and desalting performance with silver nanoparticle modifications (NaCl removal ratio of 67.5%, current efficiency of 96.9%) [15]. Meanwhile, [PERSON] et al. reported nearly complete salt removal (99.1%) and high efficiency (97.4%) with graphene oxide nanocomposites [16]. [PERSON] et al. developed asymmetric cation exchange membranes, demonstrating a salinity reduction rate of 91.9% and energy efficiency of 127.5% [17]. However, in spite of these performance enhancements, the integration of nanoparticles into membranes presents challenges, including complex synthesis processes and material handling difficulties, which hinder large-scale industrial application. To address these challenges, this work focuses on the development of ion exchange membranes using simple polyethersulfone (PES) and sulfonated PES (sPES). The straightforward fabrication process involves phase inversion, avoiding the need for complex additives or multistep synthesis. This approach aims to provide cost-effective, high-performance membranes suitable for brackish water desalination applications.