PES/DBR membranes are known to exhibit instability when exposed to strong alkaline conditions, primarily due to the leaching of additives and the degradation of polyphenolic compounds. The study explores the effect of Fe3+ concentration on the properties and performance of PES/DBR-Fe membranes. Five types of membranes were prepared with varying concentrations of Fe3+ from 0 – 0,05 M in the coagulation bath. Membranes were subjected to evaluation considering their characteristics, performance, and chemical stability under strong alkaline solution (NaOH 0,01 N for 48 h). The results indicate that increasing the Fe3+ concentration had minimal effects on contact angle, water uptake, and membrane functional groups. However, it notably influenced the cross-sectional structure and porosity of the membrane. Higher Fe3+ concentrations led to a decrease in pure permeability but maintained a satisfactory rejection rate of >95%. Of all the concentrations investigated, the membrane with a 0.05 M exhibits the smallest increase in flux ratio, thus demonstrating the highest stability. This study explores strategies to enhance the chemical stability of membrane, focusing on the incorporation of novel coordinated covalent compounds between anthocyanin and Fe3+.