Synthesis and Corrosion Protection of 3:1 MgAl Layered Double Hydroxides: Metals Concentration Study via Coprecipitation

This study investigates the effect of metal ion concentration on the formation and properties of Mg-Al Layered Double Hydroxides (LDHs) with a fixed Mg²⁺/Al³⁺ molar ratio of 3:1. While previous studies often report this ratio, the influence of concentration on LDH purity and structure remains less explored. LDH samples synthesized through coprecipitation method at varying concentrations were characterized using PXRD, TGA, FTIR, FESEM, BET surface area analysis, and elemental analysis techniques. The findings confirm the successful formation of nitrate-intercalated LDHs across all concentrations, with consistent structural and morphological features. Although metal concentration influenced the crystallinity and surface characteristics, the highest metal concentration LDH (S3) was observed to efficiently inhibit the corrosion of mild steel in neutral NaCl solution through ion-exchange process. HIGHLIGHTS Nitrate-intercalated LDHs were successfully obtained at all concentrations with consistent layered structures. Higher metal ion concentration enhanced LDH crystallinity and surface properties. The LDH prepared at the highest concentration (S3) showed superior corrosion inhibition of mild steel in NaCl solution through the ion-exchange mechanism. GRAPHICAL ABSTRACT